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2020 Vol. 38, No. 1
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2020, 38(1): 1-12,36.
doi: 10.13205/j.hjgc.202001001
Abstract:
Rare earth materials are widely used in the field of air pollution control due to their rich hydroxyl groups, surface lattice defects and high-temperature stability, combined with their strong VOCs affinity and excellent oxygen storage and release capabilities. Recent studies have found that some rare earth-based materials are better than noble metal catalysts in the treatment of organic waste gases, and have explored in a wide range of prospects in practical engineering applications. Based on the literature and engineering investigations, the current status of rare earth-based materials in the fields of catalysis, adsorption, and practical engineering at home and abroad is reviewed. The advantages of rare earth materials and the problems they are currently facing are analyzed. The development trends of rare earth materials at home and abroad are analyzed and predicted from the perspective of adsorption, catalysis, etc. At the same time, the key issues and solutions in development are pointed out in accordance with China's current national conditions, in order to provide references for the future development of rare earth materials in the field of organic waste gas treatment.
Rare earth materials are widely used in the field of air pollution control due to their rich hydroxyl groups, surface lattice defects and high-temperature stability, combined with their strong VOCs affinity and excellent oxygen storage and release capabilities. Recent studies have found that some rare earth-based materials are better than noble metal catalysts in the treatment of organic waste gases, and have explored in a wide range of prospects in practical engineering applications. Based on the literature and engineering investigations, the current status of rare earth-based materials in the fields of catalysis, adsorption, and practical engineering at home and abroad is reviewed. The advantages of rare earth materials and the problems they are currently facing are analyzed. The development trends of rare earth materials at home and abroad are analyzed and predicted from the perspective of adsorption, catalysis, etc. At the same time, the key issues and solutions in development are pointed out in accordance with China's current national conditions, in order to provide references for the future development of rare earth materials in the field of organic waste gas treatment.
2020, 38(1): 13-20.
doi: 10.13205/j.hjgc.202001002
Abstract:
Volatile organic compounds (VOCs) is one of the major contributors to air pollution. In particular, catalytic oxidation is generally considered as the most efficient way to entirely decompose the wide range of VOCs into harmless products of CO2 and H2O. This review summarizes recent progress of researches into various catalysts for the catalytic destruction of VOCs, and emphatically highlights the scientific understanding in the catalyst design and reaction mechanism of light-driven thermocatalysis/photo-thermocatalysis, based on the traditional thermal catalysis with high energy consumption and the photocatalysis with low quantum efficiency in VOCs purification. Since the direct conversion of renewable clean solar energy into thermal and chemical energy to drive catalytic reaction is highly desirable, this review also presents a broad perspective on the state of strategy research for light-driven photo-thermocatalysis and prospects for strategy research in the future.
Volatile organic compounds (VOCs) is one of the major contributors to air pollution. In particular, catalytic oxidation is generally considered as the most efficient way to entirely decompose the wide range of VOCs into harmless products of CO2 and H2O. This review summarizes recent progress of researches into various catalysts for the catalytic destruction of VOCs, and emphatically highlights the scientific understanding in the catalyst design and reaction mechanism of light-driven thermocatalysis/photo-thermocatalysis, based on the traditional thermal catalysis with high energy consumption and the photocatalysis with low quantum efficiency in VOCs purification. Since the direct conversion of renewable clean solar energy into thermal and chemical energy to drive catalytic reaction is highly desirable, this review also presents a broad perspective on the state of strategy research for light-driven photo-thermocatalysis and prospects for strategy research in the future.
2020, 38(1): 21-27.
doi: 10.13205/j.hjgc.202001003
Abstract:
Volatile organic compounds (VOCs) were concerned by the whole society. As a mainstream terminal technology for the removal of VOCs, the absorption method had advantages including simple process, high adaptability, less secondary pollutants, low investment and operation cost. The absorbent and absorption devices were two key factors that constrain the removal efficiency of VOCs by absorption. Based on introducing the harms and common treatment technologies of VOCs, this paper briefly presented recent research results of four kinds of common absorbents (organic solvent, surfactant, micro emulsion and ionic liquid) and two common absorption devices (packed column and high-gravity rotating packed bed) for purifying VOCs containing waste gas globally, and summarized the methods of regeneration and reuse of the absorbents for the removal of VOCs. Lastly, aiming at the existing problems of the absorption method for the removal of VOCs, the key research directions in the future were proposed.
Volatile organic compounds (VOCs) were concerned by the whole society. As a mainstream terminal technology for the removal of VOCs, the absorption method had advantages including simple process, high adaptability, less secondary pollutants, low investment and operation cost. The absorbent and absorption devices were two key factors that constrain the removal efficiency of VOCs by absorption. Based on introducing the harms and common treatment technologies of VOCs, this paper briefly presented recent research results of four kinds of common absorbents (organic solvent, surfactant, micro emulsion and ionic liquid) and two common absorption devices (packed column and high-gravity rotating packed bed) for purifying VOCs containing waste gas globally, and summarized the methods of regeneration and reuse of the absorbents for the removal of VOCs. Lastly, aiming at the existing problems of the absorption method for the removal of VOCs, the key research directions in the future were proposed.
2020, 38(1): 28-36.
doi: 10.13205/j.hjgc.202001004
Abstract:
Volatile organic compounds (VOCs) have brought obvious harms. VOCs treatment has become a hot research issue. Photocatalytic degradation of VOCs had been widely studied due to its advantages such as low cost, no secondary pollution, energy saving, and high mineralization rate. Studies on photocatalysts such as TiO2, Bi2WO6, MOF and quantum dots had been applied to the degradation of VOCs. Based on this, a new type of organic-inorganic composite photocatalyst was constructed. In the process of constructing the organic-inorganic composite photocatalyst, organic and inorganic components of the composite catalyst, structure of the catalyst, and control of photo-generated electrons were reviewed to improve the photocatalytic activity of the catalyst, and to prepare an innovation path for organic-inorganic composite photodegradation catalyst for VOCs removal.
Volatile organic compounds (VOCs) have brought obvious harms. VOCs treatment has become a hot research issue. Photocatalytic degradation of VOCs had been widely studied due to its advantages such as low cost, no secondary pollution, energy saving, and high mineralization rate. Studies on photocatalysts such as TiO2, Bi2WO6, MOF and quantum dots had been applied to the degradation of VOCs. Based on this, a new type of organic-inorganic composite photocatalyst was constructed. In the process of constructing the organic-inorganic composite photocatalyst, organic and inorganic components of the composite catalyst, structure of the catalyst, and control of photo-generated electrons were reviewed to improve the photocatalytic activity of the catalyst, and to prepare an innovation path for organic-inorganic composite photodegradation catalyst for VOCs removal.
2020, 38(1): 37-41,20.
doi: 10.13205/j.hjgc.202001005
Abstract:
Cooking fume not only has multiple environmental impact on the atmospheric quality, but also endangers health and living space of human beings. Firstly, we analyzed the emission characteristics and chemical properties of cooking fume, aiming at the problem of cooking fume pollution. Secondly, we discussed the traditional cooking fume purification and VOCs control technologies, summarized their advantages and disadvantages, and introduced the technical prospects which featured combining traditional fume purification technologies together with VOCs control technologies. Finally, we put forward suggestions on the emission reduction of cooking fume, based on the actual laws and emission standards in China.
Cooking fume not only has multiple environmental impact on the atmospheric quality, but also endangers health and living space of human beings. Firstly, we analyzed the emission characteristics and chemical properties of cooking fume, aiming at the problem of cooking fume pollution. Secondly, we discussed the traditional cooking fume purification and VOCs control technologies, summarized their advantages and disadvantages, and introduced the technical prospects which featured combining traditional fume purification technologies together with VOCs control technologies. Finally, we put forward suggestions on the emission reduction of cooking fume, based on the actual laws and emission standards in China.
2020, 38(1): 42-47,92.
doi: 10.13205/j.hjgc.202001006
Abstract:
The pollution characteristics of PM2.5, O3, and volatile organic compound (VOCs) were analyzed in the Pearl River Delta, China. The sensitive components with greater influence on the formation of secondary organic aerosol (SOA) and O3 were also screened. The results indicated that there was obvious difference in seasonal variation of PM2.5 and O3 concentrations in the Pearl River Delta. The concentrations were the highest in January and October for PM2.5 and O3, respectively. The VOCs was dominated with alkane, accounting for 64.2% of the total VOCs mass content, followed by aromatics and alkene. The components with the highest content were butane, isopentane, isobutane and cyclohexane. The SOA generation potential was mainly contributed by aromatics, accounting for 78.5% of the total generation potential. The components with the highest SOA generation potential were toluene, m, p-xylene and ethylbenzene. The O3 generation potential was mainly contributed by alkene, accounting for 42.3% of the total generation potential, followed by aromatics (34.2%) and alkane (23.5%). The components with higher O3 generation potential were propylene, isopentadiene and 1-butene. It was suggested that priority control should be given to the sensitive components of VOCs emitted from vehicle exhaust, solvent volatilization, paint usage, and petrochemical industry to alleviate the PM2.5 and O3 pollution effectively in the Pearl River Delta.
The pollution characteristics of PM2.5, O3, and volatile organic compound (VOCs) were analyzed in the Pearl River Delta, China. The sensitive components with greater influence on the formation of secondary organic aerosol (SOA) and O3 were also screened. The results indicated that there was obvious difference in seasonal variation of PM2.5 and O3 concentrations in the Pearl River Delta. The concentrations were the highest in January and October for PM2.5 and O3, respectively. The VOCs was dominated with alkane, accounting for 64.2% of the total VOCs mass content, followed by aromatics and alkene. The components with the highest content were butane, isopentane, isobutane and cyclohexane. The SOA generation potential was mainly contributed by aromatics, accounting for 78.5% of the total generation potential. The components with the highest SOA generation potential were toluene, m, p-xylene and ethylbenzene. The O3 generation potential was mainly contributed by alkene, accounting for 42.3% of the total generation potential, followed by aromatics (34.2%) and alkane (23.5%). The components with higher O3 generation potential were propylene, isopentadiene and 1-butene. It was suggested that priority control should be given to the sensitive components of VOCs emitted from vehicle exhaust, solvent volatilization, paint usage, and petrochemical industry to alleviate the PM2.5 and O3 pollution effectively in the Pearl River Delta.
2020, 38(1): 48-53.
doi: 10.13205/j.hjgc.202001007
Abstract:
Manganese-cerium composite oxides catalyst was prepared with zeolite as the carrier. The binary catalytic performance of the catalyst for industrial typical VOCs was investigated, and the catalyst was characterized by BET, XRD and SEM. Results showed that the addition of the cerium promoted the dispersion of the manganese and improved the activity of the composite oxide catalyst.The catalytic performance of MnCeOx/zeolite was the best with n(Mn)∶n(Ce) of 1∶1, loading ratio of 20% and calcination temperature of 500 ℃, with initial and complete combustion temperatures of toluene at 155 ℃ and 255 ℃, respectively. In the single component experiment, the catalysts for three organics all showed higher activity, and the temperature of conversion of 90% was below 275 ℃; the catalytic performance decreased in the order of ethyl acetate, toluene and acetone, which was mainly affected by the level of the activation energy as well as their polarity of molecule. In the binary catalytic experiment, T50 and T90 of three organics increased respectively by 8~13 ℃ and 14~38 ℃ than that in the single component experiment, due to the competitive adsorption.
Manganese-cerium composite oxides catalyst was prepared with zeolite as the carrier. The binary catalytic performance of the catalyst for industrial typical VOCs was investigated, and the catalyst was characterized by BET, XRD and SEM. Results showed that the addition of the cerium promoted the dispersion of the manganese and improved the activity of the composite oxide catalyst.The catalytic performance of MnCeOx/zeolite was the best with n(Mn)∶n(Ce) of 1∶1, loading ratio of 20% and calcination temperature of 500 ℃, with initial and complete combustion temperatures of toluene at 155 ℃ and 255 ℃, respectively. In the single component experiment, the catalysts for three organics all showed higher activity, and the temperature of conversion of 90% was below 275 ℃; the catalytic performance decreased in the order of ethyl acetate, toluene and acetone, which was mainly affected by the level of the activation energy as well as their polarity of molecule. In the binary catalytic experiment, T50 and T90 of three organics increased respectively by 8~13 ℃ and 14~38 ℃ than that in the single component experiment, due to the competitive adsorption.
2020, 38(1): 54-59.
doi: 10.13205/j.hjgc.202001008
Abstract:
The application of different technologies was analyzed based on 398 sets of exhaust gas treatment systems in 213 key industry enterprises in typical cities of the Yangtze River Delta, including adsorption, absorption, condensation, photolysis/photocatalysis, low temperature plasma, combustion and biological treatment methods. This study analyzed the application of different combinations of the above treatment technologies and the actual purification effect of VOCs in different key industries. Results showed that the adsorption technology with broad spectrum was the most commonly used with the application propotion of 47.49%, and the purification efficiency could be as high as 90% above, when adsorption regeneration combined with end-treatment technologies such as combustion and condensation, and the amount of waste adsorbent was reduced by 90% at least, achieving the resource and energy reuse of VOCs containing waste gas. The treatment process had certain selectivity and preference, such as absorption, condensation, photolysis/photocatalysis, low temperature plasma and biological technology. The reasonable selection of technologies combination could take advantage of different processing technologies to ensure the efficiency and stability.
The application of different technologies was analyzed based on 398 sets of exhaust gas treatment systems in 213 key industry enterprises in typical cities of the Yangtze River Delta, including adsorption, absorption, condensation, photolysis/photocatalysis, low temperature plasma, combustion and biological treatment methods. This study analyzed the application of different combinations of the above treatment technologies and the actual purification effect of VOCs in different key industries. Results showed that the adsorption technology with broad spectrum was the most commonly used with the application propotion of 47.49%, and the purification efficiency could be as high as 90% above, when adsorption regeneration combined with end-treatment technologies such as combustion and condensation, and the amount of waste adsorbent was reduced by 90% at least, achieving the resource and energy reuse of VOCs containing waste gas. The treatment process had certain selectivity and preference, such as absorption, condensation, photolysis/photocatalysis, low temperature plasma and biological technology. The reasonable selection of technologies combination could take advantage of different processing technologies to ensure the efficiency and stability.
2020, 38(1): 60-64,74.
doi: 10.13205/j.hjgc.202001009
Abstract:
In this study, a new type of bola surfactant was synthesized and used as the template to prepare ZSM-5 molecular sieve (H-ZSM-5) with nano lamellar structure. The ethyl orthosilicate and sodium metaaluminate were used as silicon source and aluminum source, respectively. The H-ZSM-5 was prepared by hydrothermal method, and the mole ratio was 30 NaOH∶2.5 NaAlO2∶120 SiO2∶5 SDA∶4800 H2O. The prepared ZSM-5 molecular sieves were characterized by scanning electron microscopy, transmission electron microscopy, X-ray and nitrogen adsorption, thermogravimetric analysis, etc. The static adsorption experiments of formaldehyde on the traditional ZSM-5 and H-ZSM-5 were carried out. It was found that the adsorption capacity of H-ZSM-5 molecular sieve was significantly higher than that of the traditional microporous ZSM-5. The evaluation of adsorption performance by using toluene vapor molecule with larger molecular diameter showed that the nano-sheet H-ZSM-5 zeolite had the ability to adsorb VOCs molecules with larger molecular structure and the applying potential in indoor air purification.
In this study, a new type of bola surfactant was synthesized and used as the template to prepare ZSM-5 molecular sieve (H-ZSM-5) with nano lamellar structure. The ethyl orthosilicate and sodium metaaluminate were used as silicon source and aluminum source, respectively. The H-ZSM-5 was prepared by hydrothermal method, and the mole ratio was 30 NaOH∶2.5 NaAlO2∶120 SiO2∶5 SDA∶4800 H2O. The prepared ZSM-5 molecular sieves were characterized by scanning electron microscopy, transmission electron microscopy, X-ray and nitrogen adsorption, thermogravimetric analysis, etc. The static adsorption experiments of formaldehyde on the traditional ZSM-5 and H-ZSM-5 were carried out. It was found that the adsorption capacity of H-ZSM-5 molecular sieve was significantly higher than that of the traditional microporous ZSM-5. The evaluation of adsorption performance by using toluene vapor molecule with larger molecular diameter showed that the nano-sheet H-ZSM-5 zeolite had the ability to adsorb VOCs molecules with larger molecular structure and the applying potential in indoor air purification.
2020, 38(1): 75-79,86.
doi: 10.13205/j.hjgc.202001011
Abstract:
The p-arsanilic acid adsorbent MFB-MCs was prepared by co-precipitation method with vinasse, manganese sulfate monohydrate (MnSO4·H2O) and ferric chloride hexahydrate (FeCl3·6H2O) as the raw materials. The SEM and TEM analysis and characterization of MFB-MCs were carried out. The effects of initial solution pH, adsorption dose, temperature and time on the adsorption of p-arsanilic acid were investigated. The results showed that MFB-MCs could effectively remove the p-arsanilic acid in aqueous solution; the influences of initial pH on adsorption process of MFB-MCs to p-arsanilic acid in water was greater. With the condition of temperature of 25 ℃, initial solution pH of 2.0, the adsorption dose of 1 g/L, after 1440 minutes adsorption, the removal rate of p-arsanilic acid with initial concentration of 20 mg/L reached 82.27%; the adsorption process of MFB-MCs on p-arsanilic acid conformed to the pseudo-second-order kinetic model, so it was mainly controlled by chemical adsorption. At the same time, the adsorption process conformed to the Freundlich isotherm model, which belonged to multi-layer adsorption process.
The p-arsanilic acid adsorbent MFB-MCs was prepared by co-precipitation method with vinasse, manganese sulfate monohydrate (MnSO4·H2O) and ferric chloride hexahydrate (FeCl3·6H2O) as the raw materials. The SEM and TEM analysis and characterization of MFB-MCs were carried out. The effects of initial solution pH, adsorption dose, temperature and time on the adsorption of p-arsanilic acid were investigated. The results showed that MFB-MCs could effectively remove the p-arsanilic acid in aqueous solution; the influences of initial pH on adsorption process of MFB-MCs to p-arsanilic acid in water was greater. With the condition of temperature of 25 ℃, initial solution pH of 2.0, the adsorption dose of 1 g/L, after 1440 minutes adsorption, the removal rate of p-arsanilic acid with initial concentration of 20 mg/L reached 82.27%; the adsorption process of MFB-MCs on p-arsanilic acid conformed to the pseudo-second-order kinetic model, so it was mainly controlled by chemical adsorption. At the same time, the adsorption process conformed to the Freundlich isotherm model, which belonged to multi-layer adsorption process.
2020, 38(1): 80-86.
doi: 10.13205/j.hjgc.202001012
Abstract:
In municipal wastewater treatment plants, wastewater treatment facilities are usually covered by a great amount of algae. To solve this problem, in this study, quaternary ammonium compound (QAC)/epoxy composite coatings were prepared by blending QAC into epoxy paint. Effects of QAC dosage on the physicochemical properties and anti-algal adhesion/growth behaviors of the composite coatings were investigated. The results showed that QAC was successfully present on the modified coating and more quaternary ammonium groups (R4N+) were loaded on the surface with the increase of QAC dosage. No significant differences in hydrophobicity and water stabilities were observed between epoxy coating and the modified ones. Compared to the original coating, zeta potential of composite coatings was shifted towards less negative potential and roughness was slightly lower as the result of QAC dosing. The inhibition properties of algae of the coatings were evaluated using Chlorella vulgaris as the model algae. Less Chlorella vulgaris were adhered on QAC/epoxy composite coatings than epoxy coating and better anti-algae performance was obtained with higher QAC concentration.
In municipal wastewater treatment plants, wastewater treatment facilities are usually covered by a great amount of algae. To solve this problem, in this study, quaternary ammonium compound (QAC)/epoxy composite coatings were prepared by blending QAC into epoxy paint. Effects of QAC dosage on the physicochemical properties and anti-algal adhesion/growth behaviors of the composite coatings were investigated. The results showed that QAC was successfully present on the modified coating and more quaternary ammonium groups (R4N+) were loaded on the surface with the increase of QAC dosage. No significant differences in hydrophobicity and water stabilities were observed between epoxy coating and the modified ones. Compared to the original coating, zeta potential of composite coatings was shifted towards less negative potential and roughness was slightly lower as the result of QAC dosing. The inhibition properties of algae of the coatings were evaluated using Chlorella vulgaris as the model algae. Less Chlorella vulgaris were adhered on QAC/epoxy composite coatings than epoxy coating and better anti-algae performance was obtained with higher QAC concentration.
2020, 38(1): 87-92.
doi: 10.13205/j.hjgc.202001013
Abstract:
The effect of suspended carriers addition on COD removal characteristics, sludge mixed liquor properties and membrane fouling in a separated anaerobic membrane bioreactor(AnMBR) were studied. The results showed when the organic load was 2.09 kg/(m3·d), the sludge load was 0.54 kg/(kg·d), the hydraulic retention time(HRT) was 48 h, and the temperature was (35±2) ℃, compared with the stage that suspended carriers was not added, the COD removal rate of the AnMBR increased from 96.6% to 97.9%, and methane yield increased by 16%. Meanwhile, the average sludge particle size of the AnMBR mixture increased, the cake resistance, total filtration resistance, the proportion of cake resistance in total resistance were reduced by 7.8%, 6.5% and 1.3%, the concentration of soluble extracellular polymeric substances (SEPS) and bound extracellular polymeric substances (BEPS) decreased by 20.5% and 29.4%, the linear growth rate of the transmembrane pressure(TMP) was reduced, and the membrane fouling cycle was slowed down significantly, after the suspended carriers was added. Without extra energy consumption, the addition of suspended carriers could improve the properties of the sludge mixture of AnMBR, also strengthen the treatment effect and control the membrane fouling.
The effect of suspended carriers addition on COD removal characteristics, sludge mixed liquor properties and membrane fouling in a separated anaerobic membrane bioreactor(AnMBR) were studied. The results showed when the organic load was 2.09 kg/(m3·d), the sludge load was 0.54 kg/(kg·d), the hydraulic retention time(HRT) was 48 h, and the temperature was (35±2) ℃, compared with the stage that suspended carriers was not added, the COD removal rate of the AnMBR increased from 96.6% to 97.9%, and methane yield increased by 16%. Meanwhile, the average sludge particle size of the AnMBR mixture increased, the cake resistance, total filtration resistance, the proportion of cake resistance in total resistance were reduced by 7.8%, 6.5% and 1.3%, the concentration of soluble extracellular polymeric substances (SEPS) and bound extracellular polymeric substances (BEPS) decreased by 20.5% and 29.4%, the linear growth rate of the transmembrane pressure(TMP) was reduced, and the membrane fouling cycle was slowed down significantly, after the suspended carriers was added. Without extra energy consumption, the addition of suspended carriers could improve the properties of the sludge mixture of AnMBR, also strengthen the treatment effect and control the membrane fouling.
2020, 38(1): 93-98,104.
doi: 10.13205/j.hjgc.202001014
Abstract:
Two different mixed sludge, anaerobic granular sludge (R1), and anaerobic granular sludge with mature anaerobic ammonium oxidation (ANAMMOX) sludge (R2) were used as the inocula in two up-flow reactors to enrich anaerobic ammonia-oxidizing bacteria (AnAOB), respectively. The total nitrogen removal rate of R1 reached 74% in 99 days, while R2 remained above 70% in only 48 days. The content of extracellular polymeric substance (EPS) in the sludge was found to increase with the increase of the influent nitrogen loading, which might attribute to the sludge granulation. It was interesting to notice that the dominant AnAOB genera in two systems were different, i.e. Candidatus Kuenenia (7.92%) in R1, and Candidatus Brocadia (15.64%) in R2. Candidatus Kuenenia also existed in R2, accounting for 3.02%. R1 maintained considerable denitrification efficiency in the case of lower anaerobic ammonium oxidizing bacteria abundance and might have more potential for long-term culture.
Two different mixed sludge, anaerobic granular sludge (R1), and anaerobic granular sludge with mature anaerobic ammonium oxidation (ANAMMOX) sludge (R2) were used as the inocula in two up-flow reactors to enrich anaerobic ammonia-oxidizing bacteria (AnAOB), respectively. The total nitrogen removal rate of R1 reached 74% in 99 days, while R2 remained above 70% in only 48 days. The content of extracellular polymeric substance (EPS) in the sludge was found to increase with the increase of the influent nitrogen loading, which might attribute to the sludge granulation. It was interesting to notice that the dominant AnAOB genera in two systems were different, i.e. Candidatus Kuenenia (7.92%) in R1, and Candidatus Brocadia (15.64%) in R2. Candidatus Kuenenia also existed in R2, accounting for 3.02%. R1 maintained considerable denitrification efficiency in the case of lower anaerobic ammonium oxidizing bacteria abundance and might have more potential for long-term culture.
2020, 38(1): 99-104.
doi: 10.13205/j.hjgc.202001015
Abstract:
A photosynthetic bacteria R1 with nitrogen and phosphorus removal ability was isolated from the landfill leachate and identified as Rhodopseudomonas palustris. R1 was added to a SBR system to study the effect of strengthening the treatment of landfill leachate and analyze the composition of the bacteria community in the reactor. The results showed that the removal rates of COD, NH4+-N and TP were 76.895%, 65.964% and 94.036%, respectively, in the SBR reactor with photosynthetic bacteria in the experimental group, and the sludge yield was significantly lower than that of the control group. The results of high-throughput sequencing showed that Proteobacteria, Chlorobacteria, Firmicutes, Acidobacteria and Bacteroidetes were the dominant bacteria. Under the combined action of Caldilineaceae, Acinetobacter, Pseudomonas, etc., R1 could not only stably exist in the activated sludge, but also effectively improve the microbial community structure in the activated sludge and improve its nitrogen and phosphorus removal performance.
A photosynthetic bacteria R1 with nitrogen and phosphorus removal ability was isolated from the landfill leachate and identified as Rhodopseudomonas palustris. R1 was added to a SBR system to study the effect of strengthening the treatment of landfill leachate and analyze the composition of the bacteria community in the reactor. The results showed that the removal rates of COD, NH4+-N and TP were 76.895%, 65.964% and 94.036%, respectively, in the SBR reactor with photosynthetic bacteria in the experimental group, and the sludge yield was significantly lower than that of the control group. The results of high-throughput sequencing showed that Proteobacteria, Chlorobacteria, Firmicutes, Acidobacteria and Bacteroidetes were the dominant bacteria. Under the combined action of Caldilineaceae, Acinetobacter, Pseudomonas, etc., R1 could not only stably exist in the activated sludge, but also effectively improve the microbial community structure in the activated sludge and improve its nitrogen and phosphorus removal performance.
2020, 38(1): 105-111,134.
doi: 10.13205/j.hjgc.202001016
Abstract:
La2O3 nanoparticles, using cetrimonium bromide(CTMAB) as the surfactant, were prepared by co-precipitation method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and N2 adsorption-desorption isotherms(BET). A series of batch experiments were carried out to study the effects of solution pH, coexisting anions and ionic strength on the adsorption of As(Ⅲ) by La2O3 nanoparticles. Adsorption kinetics and adsorption isotherm models were used to simulate the adsorption process and explore the adsorption mechanism. The results showed that La2O3 prepared with 0.2% CTMAB had a higher adsorption capacity on As(Ⅲ). The optimum pH range of As(Ⅲ) adsorption was 5~9. The effect of SO2-4 and CO2-3 on the adsorption of As(Ⅲ) was insignificant, while the efficiencies of As(Ⅲ) adsorption were separately decreased to 39.14% and 25.36%, when the concentrations of SiO2-3 and PO43- were increased to 10 mmol/L. The negligible influence of ionic strength on the adsorption indicated that the adsorption was an inner layer adsorption; the adsorption of As(Ⅲ) by La2O3 nanoparticles fitted with the pseudo-secondary reaction kinetics and the Langmuir adsorption isotherm model, demonstrating that the adsorption was a monolayer adsorption. The theoretical maximum adsorption capacity of La2O3 nanoparticles was 45.5 mg/g. The mechanism for As(Ⅲ) adsorption was as follows: the hydroxyl group La—OH formed by hydroxylation of La2O3 reacted with As(Ⅲ) and generated a monodentate or bidentate complex, which removed As(Ⅲ) from aqueous solution.
La2O3 nanoparticles, using cetrimonium bromide(CTMAB) as the surfactant, were prepared by co-precipitation method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and N2 adsorption-desorption isotherms(BET). A series of batch experiments were carried out to study the effects of solution pH, coexisting anions and ionic strength on the adsorption of As(Ⅲ) by La2O3 nanoparticles. Adsorption kinetics and adsorption isotherm models were used to simulate the adsorption process and explore the adsorption mechanism. The results showed that La2O3 prepared with 0.2% CTMAB had a higher adsorption capacity on As(Ⅲ). The optimum pH range of As(Ⅲ) adsorption was 5~9. The effect of SO2-4 and CO2-3 on the adsorption of As(Ⅲ) was insignificant, while the efficiencies of As(Ⅲ) adsorption were separately decreased to 39.14% and 25.36%, when the concentrations of SiO2-3 and PO43- were increased to 10 mmol/L. The negligible influence of ionic strength on the adsorption indicated that the adsorption was an inner layer adsorption; the adsorption of As(Ⅲ) by La2O3 nanoparticles fitted with the pseudo-secondary reaction kinetics and the Langmuir adsorption isotherm model, demonstrating that the adsorption was a monolayer adsorption. The theoretical maximum adsorption capacity of La2O3 nanoparticles was 45.5 mg/g. The mechanism for As(Ⅲ) adsorption was as follows: the hydroxyl group La—OH formed by hydroxylation of La2O3 reacted with As(Ⅲ) and generated a monodentate or bidentate complex, which removed As(Ⅲ) from aqueous solution.
2020, 38(1): 112-116,145.
doi: 10.13205/j.hjgc.202001017
Abstract:
This paper described an optimal zero-emission process for high-salt wastewater. Through redesign of the post-treatment process of the conventional wastewater zero-emission process, with the aim of optimizing the method and maximizing the economic benefits, various methods of the important steps in the process were demonstrated and screened, and the actual process was established as chemical softening-tube microfiltration-nanofiltration-reverse osmosis (RO)-dish-tube reverse osmosis (DTRO). The combined route of the evaporative crystallization system (for salt nitrate production) was applied to recover Na2SO4 and NaCl sequentially. Multiple detection methods was used on the generated NaCl through crystallization, and the quality of sodium chloride product was proved to reach the superior grade of Industrial Salt (GB/T 5462—2015), and the external sales were realized. Zero pollution and discharge were truly achieved by the total recycling of wastewater.
This paper described an optimal zero-emission process for high-salt wastewater. Through redesign of the post-treatment process of the conventional wastewater zero-emission process, with the aim of optimizing the method and maximizing the economic benefits, various methods of the important steps in the process were demonstrated and screened, and the actual process was established as chemical softening-tube microfiltration-nanofiltration-reverse osmosis (RO)-dish-tube reverse osmosis (DTRO). The combined route of the evaporative crystallization system (for salt nitrate production) was applied to recover Na2SO4 and NaCl sequentially. Multiple detection methods was used on the generated NaCl through crystallization, and the quality of sodium chloride product was proved to reach the superior grade of Industrial Salt (GB/T 5462—2015), and the external sales were realized. Zero pollution and discharge were truly achieved by the total recycling of wastewater.
2020, 38(1): 117-121.
doi: 10.13205/j.hjgc.202001018
Abstract:
Focusing on the environmental risks of heavy metals contained in discarded LCD panels, the contents of nine major toxic and harmful metals in three typical LCD panels, desktop computer display, notebooks and liquid crystal television were analyzed. Furthermore, the occurrence forms, ecological risks and leaching toxicity of metals were analyzed and evaluated by BCR sequential extraction method, individual contamination factors method (ICF) and TCLP standard toxicity leaching method respectively. The results showed that As had the highest concentration in LCD panel in the experimental range, which was 1.8×103 mg/kg, followed by Zn, Cr, Sn, Ni, In, Cu and Cd, with their concentration ranging from 26.20~413.00 mg/kg, and Pb was not detected. In LCD panels, As, Cd, Sn, Cr, Ni and Zn mainly existed in residual form, with a lower ecological risk level. In and Cu took the reducible state as their main existing form, with higher ecological risk level. As, Ni and Zn had certain leaching toxicity risks, in which the leaching concentration of As and Ni exceeded the limit of toxicological index of Rank Ⅲ of Groundwater Quality Standard (GB/T 14848—2017), and the leaching concentration of Zn exceeded the limit of general chemical index of rank Ⅲ of GB/T 14848—2017.
Focusing on the environmental risks of heavy metals contained in discarded LCD panels, the contents of nine major toxic and harmful metals in three typical LCD panels, desktop computer display, notebooks and liquid crystal television were analyzed. Furthermore, the occurrence forms, ecological risks and leaching toxicity of metals were analyzed and evaluated by BCR sequential extraction method, individual contamination factors method (ICF) and TCLP standard toxicity leaching method respectively. The results showed that As had the highest concentration in LCD panel in the experimental range, which was 1.8×103 mg/kg, followed by Zn, Cr, Sn, Ni, In, Cu and Cd, with their concentration ranging from 26.20~413.00 mg/kg, and Pb was not detected. In LCD panels, As, Cd, Sn, Cr, Ni and Zn mainly existed in residual form, with a lower ecological risk level. In and Cu took the reducible state as their main existing form, with higher ecological risk level. As, Ni and Zn had certain leaching toxicity risks, in which the leaching concentration of As and Ni exceeded the limit of toxicological index of Rank Ⅲ of Groundwater Quality Standard (GB/T 14848—2017), and the leaching concentration of Zn exceeded the limit of general chemical index of rank Ⅲ of GB/T 14848—2017.
2020, 38(1): 122-127.
doi: 10.13205/j.hjgc.202001019
Abstract:
Construction and Demolition Waste (C&DW) recycling has not yet been a common practice in China. One of the key obstacles was the improper location of the recycling plants, which led to high cost of C&DW recycling. Therefore, it was of great significance to reduce the collection and transportation cost of bulk C&DW through information integration and accurate matching of supply and demand information. A multi criterial location optimization scheme was put forward, with transportation cost as the main objective. Taking Chongqing metropolis as a case study, the study was conducted on the basis of reasonable prediction, combining grey model with exponential smoothing method to estimate the annual output of C&DW. The optimization model of site selection of C&DW recycling plant based on GIS was proposed, and the optimization scheme of site selection C&DW recycling plant was formed.
Construction and Demolition Waste (C&DW) recycling has not yet been a common practice in China. One of the key obstacles was the improper location of the recycling plants, which led to high cost of C&DW recycling. Therefore, it was of great significance to reduce the collection and transportation cost of bulk C&DW through information integration and accurate matching of supply and demand information. A multi criterial location optimization scheme was put forward, with transportation cost as the main objective. Taking Chongqing metropolis as a case study, the study was conducted on the basis of reasonable prediction, combining grey model with exponential smoothing method to estimate the annual output of C&DW. The optimization model of site selection of C&DW recycling plant based on GIS was proposed, and the optimization scheme of site selection C&DW recycling plant was formed.
2020, 38(1): 128-134.
doi: 10.13205/j.hjgc.202001020
Abstract:
High-value carboxylate synthesis during organic waste treatment via anaerobic fermentation technology has become more and more mature. Especially, as one of the final products, caproic acid gained much more attentions, because of its high added-value, easy separation and wide utilization. As the electron donors and acceptors were both required for caproic acid synthesis by microorganisms, in this paper, we firstly introduced the mechanism of caproic acid biosynthesis (the reverse β-oxidation pathway) with using ethanol and acetic acid as the electron donor and acceptor, respectively. Moreover, metabolic substrates and fermentation influencing factors (temperature, pH, HRT, competitive pathways, hydrogen partial pressure, substrates ratio and nitrogen sources) were summarized. Currently, caproic acid production by Clostridium kluyveri with using ethanol as the electron donor was quite mature. Further, we explored the metabolic mechanism of caproic acid synthesis with using lactic acid as electron donor, and developing the fermentation technology of caproic acid production from lactic acid were considered as a promising direction in the future.
High-value carboxylate synthesis during organic waste treatment via anaerobic fermentation technology has become more and more mature. Especially, as one of the final products, caproic acid gained much more attentions, because of its high added-value, easy separation and wide utilization. As the electron donors and acceptors were both required for caproic acid synthesis by microorganisms, in this paper, we firstly introduced the mechanism of caproic acid biosynthesis (the reverse β-oxidation pathway) with using ethanol and acetic acid as the electron donor and acceptor, respectively. Moreover, metabolic substrates and fermentation influencing factors (temperature, pH, HRT, competitive pathways, hydrogen partial pressure, substrates ratio and nitrogen sources) were summarized. Currently, caproic acid production by Clostridium kluyveri with using ethanol as the electron donor was quite mature. Further, we explored the metabolic mechanism of caproic acid synthesis with using lactic acid as electron donor, and developing the fermentation technology of caproic acid production from lactic acid were considered as a promising direction in the future.
2020, 38(1): 135-140.
doi: 10.13205/j.hjgc.202001021
Abstract:
Rice husk and polyvinyl chloride (PVC) pyrolysis experiments were carried out in a thermogravimetric analyzer and corresponding kinetic analysis was carried out. It was found that the temperature of the first pyrolysis peak of rice husk in co-pyrolysis was significantly lower than that of mono-pyrolysis of rice husk, from 350℃ to 300℃, indicating that the adding of PVC elevated the pyrolysis of rice husk. When the heating rate was 20℃/min and the ratio of rice husk to PVC was 2∶1, the rate of co-pyrolysis was the highest. Three kinetic analysis methods were more powerful in explaining the existence of the phenomenon of co-pyrolysis. The Coats-Redfern method demonstrated that the co-pyrolysis activation energy was generally lower than that of mono-pyrolysis. The Ozawa method displayed that, in the pyrolysis conversion from 20% to 60%, the average activation energy of the co-pyrolysis was 37.60 kJ/mol, lower than that of mono-pyrolysis of rice husk, 41.45 kJ/mol. In the Friedman method, the activation energy of co-pyrolysis at the corresponding conversion rate was lower than that of mono-pyrolysis of rice husk. The result showed that co-pyrolysis performed as a reaction kinetic control process.
Rice husk and polyvinyl chloride (PVC) pyrolysis experiments were carried out in a thermogravimetric analyzer and corresponding kinetic analysis was carried out. It was found that the temperature of the first pyrolysis peak of rice husk in co-pyrolysis was significantly lower than that of mono-pyrolysis of rice husk, from 350℃ to 300℃, indicating that the adding of PVC elevated the pyrolysis of rice husk. When the heating rate was 20℃/min and the ratio of rice husk to PVC was 2∶1, the rate of co-pyrolysis was the highest. Three kinetic analysis methods were more powerful in explaining the existence of the phenomenon of co-pyrolysis. The Coats-Redfern method demonstrated that the co-pyrolysis activation energy was generally lower than that of mono-pyrolysis. The Ozawa method displayed that, in the pyrolysis conversion from 20% to 60%, the average activation energy of the co-pyrolysis was 37.60 kJ/mol, lower than that of mono-pyrolysis of rice husk, 41.45 kJ/mol. In the Friedman method, the activation energy of co-pyrolysis at the corresponding conversion rate was lower than that of mono-pyrolysis of rice husk. The result showed that co-pyrolysis performed as a reaction kinetic control process.
2020, 38(1): 141-145.
doi: 10.13205/j.hjgc.202001022
Abstract:
High temperature aerobic biological drying technology is effective in solving the problem of high water content, high organic matter existing in domestic waste drying in China, while the micro mechanism and influencing factors of high temperature aerobic biological drying process were very complex. On the basis of the experiments of high temperature aerobic biological drying of garbage, the important factors on biological drying were:organic matter content, microbial species, ventilation air volume, bin structure, oxygen concentration, particle size and bin insulation; the suitable range of main influence factors of high temperature aerobic biological drying was preliminarily determined as follows: the content of organic matter in garbage should be more than 15%, and suitable high temperature aerobic microbial bacteria should be inoculated (living bacteria dosage of 106~1010 CFU/mL, and the inoculation amount was about 1.5 L/t), the particle size of garbage was controlled at 95% ＜160 mm, and the ventilation air volume should meet the demand of O2 and dehumidification in the process of organic matter decomposition. The results could prouide data reference for researches on the process mechanism of high temperature aerobic biological drying technology of domestic waste.
High temperature aerobic biological drying technology is effective in solving the problem of high water content, high organic matter existing in domestic waste drying in China, while the micro mechanism and influencing factors of high temperature aerobic biological drying process were very complex. On the basis of the experiments of high temperature aerobic biological drying of garbage, the important factors on biological drying were:organic matter content, microbial species, ventilation air volume, bin structure, oxygen concentration, particle size and bin insulation; the suitable range of main influence factors of high temperature aerobic biological drying was preliminarily determined as follows: the content of organic matter in garbage should be more than 15%, and suitable high temperature aerobic microbial bacteria should be inoculated (living bacteria dosage of 106~1010 CFU/mL, and the inoculation amount was about 1.5 L/t), the particle size of garbage was controlled at 95% ＜160 mm, and the ventilation air volume should meet the demand of O2 and dehumidification in the process of organic matter decomposition. The results could prouide data reference for researches on the process mechanism of high temperature aerobic biological drying technology of domestic waste.
2020, 38(1): 146-150.
doi: 10.13205/j.hjgc.202001023
Abstract:
This paper proposed a method for detecting leakage in domestic waste landfill based on traveling wave ELM method. The new coaxial cables were laid in parallel and evenly spaced in the soil layer under the HDPE film. Due to the corrosion effect of the landfill leachate, the physical properties of the insulating protective layer and the dielectric layer of the coaxial cable were changed, thereby resulting in a solid conductor layer and the metal shield was short-circuited at the leaking plot and then generated a transient traveling wave. The main components of the traveling wave spectrum were extracted from the transient current traveling wave for preliminary leakage positioning. The regression characteristics of the ELM were used to reduce the detection error caused by the variation of distributed inductance and distributed capacitance in the cable in the leakage zone. The experimental results showed that the signal energy transmission of coaxial cable was concentrated, the positioning accuracy of traveling wave frequency method was not affected by the leakage distance, and the maximum error of leakage positioning after ELM optimization was 0.535%.
This paper proposed a method for detecting leakage in domestic waste landfill based on traveling wave ELM method. The new coaxial cables were laid in parallel and evenly spaced in the soil layer under the HDPE film. Due to the corrosion effect of the landfill leachate, the physical properties of the insulating protective layer and the dielectric layer of the coaxial cable were changed, thereby resulting in a solid conductor layer and the metal shield was short-circuited at the leaking plot and then generated a transient traveling wave. The main components of the traveling wave spectrum were extracted from the transient current traveling wave for preliminary leakage positioning. The regression characteristics of the ELM were used to reduce the detection error caused by the variation of distributed inductance and distributed capacitance in the cable in the leakage zone. The experimental results showed that the signal energy transmission of coaxial cable was concentrated, the positioning accuracy of traveling wave frequency method was not affected by the leakage distance, and the maximum error of leakage positioning after ELM optimization was 0.535%.
2020, 38(1): 151-156,161.
doi: 10.13205/j.hjgc.202001024
Abstract:
Metabolomics method based on gas chromatography-mass spectrometry (GC-MS) was used to analyze the intracellular metabolites of Cupriavidus necator to obtain potential metabolic biomarkers and reveal the mechanism of poly-3-hydroxybutyrate (PHB) accumulation. The metabolite levels of bacteria under different pH conditions such as 6, 7, 8 and 9 were investigated. The metabolites data was analyzed by partial least-squares discrimination analysis (PLS-DA), which presented distinct difference between the samples of four different conditions. As the pH changes, 11 substances showed significant differences, including ornithine, fumarate, β-D-glucose, glutaric acid, inositol, butyric acid, glycine, L-asparagine, d-glucose, L-threonine and valine. According to PLS-DA and metabolic pathway analysis, glycine, ornithine, threonine, sparagine and fumaric acid were potential metabolic biomarkers. These metabolites influenced PHB production through the metabolic pathways of TCA cycle pathway, amino acid anabolism and pyruvate synthesis degradation.
Metabolomics method based on gas chromatography-mass spectrometry (GC-MS) was used to analyze the intracellular metabolites of Cupriavidus necator to obtain potential metabolic biomarkers and reveal the mechanism of poly-3-hydroxybutyrate (PHB) accumulation. The metabolite levels of bacteria under different pH conditions such as 6, 7, 8 and 9 were investigated. The metabolites data was analyzed by partial least-squares discrimination analysis (PLS-DA), which presented distinct difference between the samples of four different conditions. As the pH changes, 11 substances showed significant differences, including ornithine, fumarate, β-D-glucose, glutaric acid, inositol, butyric acid, glycine, L-asparagine, d-glucose, L-threonine and valine. According to PLS-DA and metabolic pathway analysis, glycine, ornithine, threonine, sparagine and fumaric acid were potential metabolic biomarkers. These metabolites influenced PHB production through the metabolic pathways of TCA cycle pathway, amino acid anabolism and pyruvate synthesis degradation.
2020, 38(1): 157-161.
doi: 10.13205/j.hjgc.202001025
Abstract:
In this paper, a compound was made from copper tailing and polishing mud to replace fly ash and then add the cement, lime, gypsum and other materials to prepare the autoclaved aerated concrete. The influence of particle fineness, dosage and technological parameters on the compressive strength and dry density of autoclaved aerated concrete block was studied. The microscopic mechanism was studied by XRD and SEM. The experimental results showed that when copper tailing and ceramic polishing mud were grinding for 20 min, the surface area of copper tailing and ceramic polishing mad were 244.5 m2/kg and 350.4 m2/kg. With the mixing ratio of raw materials for copper tailings was polishing mud∶cement∶lime∶gypsum=45∶20∶10∶22∶3, the maximum compressive strength of the block reached 5.1 MPa, the average compressive strength reached 4.7 MPa, and the dry density was less than 625 kg/m3, complete complied with the requirements of autoclaved aerated concrete block of A3.5 B06. Tobermorite, C-S-H(B) and other hydration products in the block was closely interposed with unreacted quartz, which made the microcosmic pore structure of the block more compacter and the compressive strength higher.
In this paper, a compound was made from copper tailing and polishing mud to replace fly ash and then add the cement, lime, gypsum and other materials to prepare the autoclaved aerated concrete. The influence of particle fineness, dosage and technological parameters on the compressive strength and dry density of autoclaved aerated concrete block was studied. The microscopic mechanism was studied by XRD and SEM. The experimental results showed that when copper tailing and ceramic polishing mud were grinding for 20 min, the surface area of copper tailing and ceramic polishing mad were 244.5 m2/kg and 350.4 m2/kg. With the mixing ratio of raw materials for copper tailings was polishing mud∶cement∶lime∶gypsum=45∶20∶10∶22∶3, the maximum compressive strength of the block reached 5.1 MPa, the average compressive strength reached 4.7 MPa, and the dry density was less than 625 kg/m3, complete complied with the requirements of autoclaved aerated concrete block of A3.5 B06. Tobermorite, C-S-H(B) and other hydration products in the block was closely interposed with unreacted quartz, which made the microcosmic pore structure of the block more compacter and the compressive strength higher.
2020, 38(1): 162-166,127.
doi: 10.13205/j.hjgc.202001026
Abstract:
This paper summarized and commented on the influencing factors of livestock manure vermicomposting, including the species of earthworm, temperature and moisture, C/N ratio, livestock manure type and maturity extent, and compositing density. And the addition of effective microorganism in the vermicomposting and the potential application of vermicompost in agriculture were summarized. It was recommended that the vermicompost and organic fertilizer could be used together for present situation. On this basis, the prospect of livestock manure vermicomposting was put forward, which could provide reference for the promotion and application of vermicomposting in the future.
This paper summarized and commented on the influencing factors of livestock manure vermicomposting, including the species of earthworm, temperature and moisture, C/N ratio, livestock manure type and maturity extent, and compositing density. And the addition of effective microorganism in the vermicomposting and the potential application of vermicompost in agriculture were summarized. It was recommended that the vermicompost and organic fertilizer could be used together for present situation. On this basis, the prospect of livestock manure vermicomposting was put forward, which could provide reference for the promotion and application of vermicomposting in the future.
2020, 38(1): 167-171.
doi: 10.13205/j.hjgc.202001027
Abstract:
In order to study the surface soil of old town of Shenyang City,10 soil samples were collected in five major urban areas.The content of Zn, Cr, Ni, Pb, Cu, As and Cd in soil samples was determined by flame atomic absorption spectrometry and atomic fluorescence spectrometry,and their distribution characteristics were analyzed.The single factor pollution index method, potential ecological risk and human exposure risk assessment were used to analyze environmental risk and human exposure risk.The results showed that the average content of six heavy metals except As in old town was higher than that of Shenyang background values, among which the average content of Zn, Cd and Pb reached 3.45, 3.03 and 2.67 times of the background values; The single factor pollution index method result showed that As was in a clean state, but all the other elements had different levels of pollution, especially Zn and Cd reached heavy pollution level.The potential ecological risk result showed that Cd reached strong harm and other elements belong to slight level, and the total potential ecological risk index of the city, RI=44.28, belong to medium level of risk.Human exposure risk assessment result showed that children’s daily average exposure and non-carcinogenic risk were higher than that of adults, but the total non-carcinogenic risk of the studied heavy metals was less than 1, and the risk of carcinogenic heavy metals was also low.
In order to study the surface soil of old town of Shenyang City,10 soil samples were collected in five major urban areas.The content of Zn, Cr, Ni, Pb, Cu, As and Cd in soil samples was determined by flame atomic absorption spectrometry and atomic fluorescence spectrometry,and their distribution characteristics were analyzed.The single factor pollution index method, potential ecological risk and human exposure risk assessment were used to analyze environmental risk and human exposure risk.The results showed that the average content of six heavy metals except As in old town was higher than that of Shenyang background values, among which the average content of Zn, Cd and Pb reached 3.45, 3.03 and 2.67 times of the background values; The single factor pollution index method result showed that As was in a clean state, but all the other elements had different levels of pollution, especially Zn and Cd reached heavy pollution level.The potential ecological risk result showed that Cd reached strong harm and other elements belong to slight level, and the total potential ecological risk index of the city, RI=44.28, belong to medium level of risk.Human exposure risk assessment result showed that children’s daily average exposure and non-carcinogenic risk were higher than that of adults, but the total non-carcinogenic risk of the studied heavy metals was less than 1, and the risk of carcinogenic heavy metals was also low.
2020, 38(1): 172-177,27.
doi: 10.13205/j.hjgc.202001028
Abstract:
To better understand phthalate esters (PAEs) pollution in key areas of drinking water sources in Guiyang, water samples were collected for content analysis, quantitative analysis of organic pollutants of PAEs in Aha Reservoir, Hongfeng Lake and Baihua Lake Waters by triple quadrupole mass spectrometry (GC/MSMS). Results showed that the PAEs in the water of the study area were mainly DEP,DBP, DIBP, DEHP. PAEs were unstable in the wet season, the flat water period and the dry season; the carcinogenic and non-carcinogenic risk values of PAEs in the water source of the study area were lower than the acceptable reference values; the health risk value calculated by Method I was much lower than the recommended values of the USEPA, ICRP and Swedish EPA, etc. The health risk values calculated by Method II was close to the recommended values of the above-mentioned organizations.The PAEs in the drinking water sources of Guiyang did not pose health risks or cancer risk. The content of PAEs in water was basically at the same level as that of some domestic drinking water sources.
To better understand phthalate esters (PAEs) pollution in key areas of drinking water sources in Guiyang, water samples were collected for content analysis, quantitative analysis of organic pollutants of PAEs in Aha Reservoir, Hongfeng Lake and Baihua Lake Waters by triple quadrupole mass spectrometry (GC/MSMS). Results showed that the PAEs in the water of the study area were mainly DEP,DBP, DIBP, DEHP. PAEs were unstable in the wet season, the flat water period and the dry season; the carcinogenic and non-carcinogenic risk values of PAEs in the water source of the study area were lower than the acceptable reference values; the health risk value calculated by Method I was much lower than the recommended values of the USEPA, ICRP and Swedish EPA, etc. The health risk values calculated by Method II was close to the recommended values of the above-mentioned organizations.The PAEs in the drinking water sources of Guiyang did not pose health risks or cancer risk. The content of PAEs in water was basically at the same level as that of some domestic drinking water sources.
2020, 38(1): 178-182.
doi: 10.13205/j.hjgc.202001029
Abstract:
Taking the real case of diesel leakage in an electroplating enterprise in Zhuhai, Guangdong Province as the example, the ectopic repair extraction technology was used to treat the contaminated groundwater, and the surface leaching process was used to treat the contaminated soil. In this study, nine nozzles were set up in the excavation area of the leaking point, with the sprinkling water rate of 1.3 m3/h, and the spraying duration of 2 h/d. There were 5 nozzles in the western green belt of the leakage point, with the sprinkling water rate of 0.7 m3/h, and spraying duration of 9 h/d. The leaching water entered the groundwater and was then pumped to the sewage treatment plant for later treatment. After 9 months, treatment, the final concentration of petroleum in groundwater was lower than 0.3 mg/L, reaching the limit of petroleum in the Sanitary Standard for Drinking Water (GB 5749—2006).
Taking the real case of diesel leakage in an electroplating enterprise in Zhuhai, Guangdong Province as the example, the ectopic repair extraction technology was used to treat the contaminated groundwater, and the surface leaching process was used to treat the contaminated soil. In this study, nine nozzles were set up in the excavation area of the leaking point, with the sprinkling water rate of 1.3 m3/h, and the spraying duration of 2 h/d. There were 5 nozzles in the western green belt of the leakage point, with the sprinkling water rate of 0.7 m3/h, and spraying duration of 9 h/d. The leaching water entered the groundwater and was then pumped to the sewage treatment plant for later treatment. After 9 months, treatment, the final concentration of petroleum in groundwater was lower than 0.3 mg/L, reaching the limit of petroleum in the Sanitary Standard for Drinking Water (GB 5749—2006).
