REMOVAL OF CADMIUM AND LEAD IN WATER BY MAGNETIC CARBON PREPARED FROM ACTIVATED SLUDGE WITH HYDROTHERMAL CARBONIZATION
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摘要: 以含有FeSO4的活性污泥为原料,采用水热碳化法,在220℃,4 h条件下,制备得到磁性炭(Fe-SSBC),并实现污泥减量。以Cd2+和Pb2+为模型污染物,探究了Fe-SSBC的投加量、起始酸碱度对Cd2+和Pb2+吸附的影响以及吸附机理。采用元素分析(EA)、X射线能谱分析(EDS)、傅里叶红外光谱分析(FTIR)、比表面积(BET)、X射线光电子能谱分析(XPS)、磁滞回线对样品进行表征。研究结果表明:在投加量为0.2 g,pH为5的条件下,Fe-SSBC对Cd2+的吸附效果最好,在10 h后去除率接近100%;投加量为0.3 g,pH为6时,对Pb2+的吸附效果最佳,在8.5 h后Pb2+去除率接近100%。Fe-SSBC对Cd2+和Pb2+的吸附动力学拟合结果更符合准二级动力学模型,Langmuir吸附等温线模型能够更好地反映Cd2+和Pb2+在Fe-SSBC上的单分子层吸附,化学吸附为控制吸附过程,同时存在物理吸附。制备磁性炭在实现污泥减量的同时,具有有效去除水中Cd2+和Pb2+的作用。Abstract: Magnetic biochar (Fe-SSBC) was prepared from activated sludge containing ferrous sulfate by hydrothermal carbonization at 220℃ for 4 h, achieving sludge reduction at the same time. Using Cd2+ and Pb2+ as the model pollutants, the effect of the Fe-SSBC dosage and the initial pH on the adsorption of Cd2+ and Pb2+ were studied, then the adsorption mechanism was investigated by adsorption kinetics and adsorption isotherm experiments. The samples were characterized by elemental analysis (EA), X ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), specific surface area (BET), X ray photoelectron spectroscopy (XPS) and hysteresis loop. The results showed that optimal condition for the best Cd2+ adsorption by Fe-SSBC was dosage of 0.2 g under pH=5, after 10 h, and the removal rate was close to 100%; while that for Pb2+ adsorption was dosage of 0.3 g under pH=6, after 8.5 h, and the removal rate was close to 100%. The adsorption kinetics of Cd2+ and Pb2+ by Fe-SSBC fitted the second-order kinetic model. The adsorption isotherm model of Langmuir could better fit the monolayer adsorption of Cd2+ and Pb2+ on Fe-SSBC. Chemisorption controlled the rate of adsorption process, and there was physical adsorption at the same time. In this study, sludge reduction was achieved by hydrothermal carbonization, meanwhile, a adsorbent was prepared to remove Cd2+ and Pb2+ effectively from water.
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Key words:
- magnetic biochar /
- cadiumion /
- leadion /
- adsorption /
- water treatment
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YUAN Y, YUAN T, WANG D M, et al. Sewage sludge biochar as an efficient catalyst for oxygen reduction reaction in an microbial fuel cell[J]. Bioresource Technology, 2013, 144:115-120. HWANG I H, OUCHI Y, MATSUTO T. Characteristics of leachate from pyrolysis residue of sewage sludge[J]. Chemosphere, 2007, 68(10):1913-1919. LU H L, ZHANG W H, YANG Y X, et al. Relative distribution of Pb2+ sorption mechanisms by sludge-derived biochar[J]. Water Research, 2012, 46(3):854-862. ZHAI Y B, LIU X M, ZHU Y, et al. Hydrothermal carbonization of sewage sludge:the effect of feed-water pH on fate and risk of heavy metals in hydrochars[J]. Bioresource Technology, 2016, 218:183-188. LENG L J, YUAN X Z, HUANG H J, et al. Bio-char derived from sewage sludge by liquefaction:characterization and application for dye adsorption[J]. Applied Surface Science, 2015, 346:223-231. KIM D, LEE K, PARK K Y. Hydrothermal carbonization of anaerobically digested sludge for solid fuel production and energy recovery[J]. Fuel, 2014, 130:120-125. SHAO Y C, LONG Y Y, WANG H Y, et al. Hydrochar derived from green waste by microwave hydrothermal carbonization[J]. Renewable Energy, 2019, 135:1327-1334. KHAN SARDAR, CHAO C, WAQAS M, et al. Sewage sludge biochar influence upon rice (Oryza sativa L) yield, metal bioaccumulation and greenhouse gas emissions from acidic paddy soil[J]. Environmental Science & Technology, 2013, 47(15):8624-8632. HUANG R X, TANG Y Z. Speciation dynamics of phosphorus during (Hydro) thermal treatments of sewage sludge[J]. Environmental Science & Technology, 2015, 49(24):14466-14474. ERDOGAN E, ATILA B, MUMME J, et al. Characterization of products from hydrothermal carbonization of orange pomace including anaerobic digestibility of process liquor[J]. Bioresource Technology, 2015, 196(7):35-42. LIBRA J A, RO K S, KAMMANN C, et al. Hydrothermal carbonization of biomass residuals:a comparative review of the chemistry, processes and applications of wet and dry pyrolysis[J]. Biofuels, 2011, 2(1):71-106. IFTHIKAR J, WANG J, WANG Q, et al. Highly efficient lead distribution by magnetic sewage sludge biochar:sorption mechanisms and bench applications[J]. Bioresource Technology, 2017, 238:399-406. LU H L, ZHANG W H, YANG Y X, et al. Relative distribution of Pb2+ sorption mechanisms by sludge-derived biochar[J]. Water Research, 2012, 46(3):854-862. PEGGY A O, DIMITRI V, ROOT R, et al. The influence of sulfur and iron on dissolved arsenic concentrations in the shallow subsurface under changing redox conditions[J]. Proceedings of the National Academy of Sciences of the United States of America, 2004, 101(38):13703-13708. ZHANG F, WANG X, JI X H, et al. Efficient arsenate removal by magnetite-modified water hyacinth biochar[J]. Environmental Pollution, 2016, 216:575-583. HUANG D L, XUE W J, ZENG G M, et al. Immobilization of Cd in river sediments by sodium alginate modified nanoscale zero-valent iron:impact on enzyme activities and microbial community diversity[J]. Water Research, 2016, 106:15-25. CHEN T, ZHOU Z Y, HAN R, et al. Adsorption of cadmium by biochar derived from municipal sewage sludge:impact factors and adsorption mechanism[J]. Chemosphere, 2015, 134:286-293. KIM E J, LEE C S, CHANG Y Y, et al. Hierarchically structured manganese oxide-coated magnetic nanocomposites for the efficient removal of heavy metal ions from aqueous systems[J]. American Chemical Society, 2013, 5(19):9628-9634. ZHANG W, LO I M, TSANG D C. EDTA-enhanced washing for remediation of Pb-and/or Zn-contaminated soils[J]. Journal Environmental Engineering, 2006, 132:1282-1288. WANG P F, CAO M H, WANG C, et al. Kinetics and thermodynamics of adsorption of methylene blue by a magnetic graphene-carbon nanotube composite[J]. Applied Surface Science, 2014, 290:116-124. TANG L, YANG G D, ZENG G M, et al. Synergistic effect of iron doped ordered mesoporous carbon on adsorption-coupled reduction of hexavalent chromium and the relative mechanism study[J]. Chemical Engineering Journal, 2014, 239:114-122.
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