EFFECT OF PYROLYSIS TIME ON CHARACTERISTICS AND HEAVY METAL ECOLOGICAL RISKS IN BIOCHAR MADE FROM WASTEWATER SLUDGE
-
摘要: 研究了热解时间(1,2,4 h)对污泥炭理化性质、结构和重金属总量的影响,并对污泥炭中重金属的生态风险进行了评价。结果表明:随着热解时间逐渐延长(1~4 h),污泥炭产率和H/C均有不同程度的下降,而其灰分含量和比表面积都显著增加,污泥炭芳香化程度也明显提高。与原污泥相比,热解后污泥炭中各重金属(Cu、Zn、Pb、Cr、Mn、Ni)风险系数均显著降低。当热解时间为2 h时,污泥炭中除Zn之外,其余5种重金属都呈低风险或无风险状态,该结果可为污泥无害化处理和资源化利用提供了参考。Abstract: Pyrolysis is one of the promising technologies for wastewater sludge treatment, in which pyrolysis residence time is one of the primary factors affecting the properties of sludge biochar. This experiment studied the effects of different pyrolysis residence time (1 h, 2 h and 4 h) on physico-chemical properties, structure and total content of heavy metals in sludge biochar. In addition, the ecological risk of heavy metals in sludge biochar was also assessed. Results showed that with increase of the pyrolysis time (1~4 hours), the yield and H/C ratio of the sludge biochar were reduced to some extent, while the ash content and the specific surface area were increased accordingly, as well as the aromaticity. Compared with the raw sludge, the risk index of heavy metals, i.e. Cu, Zn, Pb, Cr, Mn, Ni in the sludge biochar was lowered significantly (p<0.05). When the pyrolysis residence time was set at 2 h, Cu, Pb, Cr, Mn, Ni, except Zn in the sludge biochar, were of lower risk, or at a risk-free status. The results could provide a theoretical basis for hazard-free treatment and resource reuse for the sludge.
-
Key words:
- sludge pyrolysis /
- sludge charcoal /
- pyrolysis residence time /
- heavy metals /
- risk assessment
-
程伟凤, 李慧, 杨艳琴, 等. 城市污泥厌氧发酵残渣热解制备生物炭及其氮磷吸附研究[J]. 化工学报, 2016, 67(4):1541-1548. JIN J W, LI Y A, ZHANG J Y, et al. Influence of pyrolysis temperature on properties and environmental safety of heavy metals in biochars derived from municipal sewage sludge[J]. Journal of Hazardous Materials, 2016, 320:417-426. JIN J W, WANG M Y, CAO Y C, et al. Cumulative effects of bamboo sawdust addition on pyrolysis of sewage sludge:biochar properties and environmental risk from metals[J]. Bioresource Technology, 2017, 228:218-226. 汤斯奇, 王经臣, JAEHAC K. 不同热解终温和保留时间下污泥生物质炭孔隙结构特征[J]. 北京大学学报(自然科学版), 2017, 53(5):890-898. 张清怡, 周琳敏, 杨燕梅, 等. 停留时间对污泥基生物炭中部分重金属的影响[J]. 福建轻纺, 2018(6):24-26. 刁韩杰, 张进, 王敏艳, 等. 高温热解对污泥炭特性及其重金属形态变化的影响[J]. 环境工程, 2019, 37(3):29-34. 葛丽炜, 夏颖, 刘书悦, 等. 热解温度和时间对马弗炉制备生物炭的影响[J]. 沈阳农业大学学报, 2018, 49(1):95-100. SINGH K P, MOHAN D, SINGH V K, et al. Studies on distribution and fractionation of heavy metals in Gomtiriver sediments:a tributary of the Ganges, India[J]. Journal of Hydrology, 2005, 312(1/2/3/4):14-27. 王圣伟, 刘刚, 冯娟, 等. 农业用地土壤重金属综合评价方法[J]. 江苏大学学报(自然科学版), 2014, 35(4):408-415. 董丽华, 李亚男, 常素云, 等. 沉积物中重金属的形态分析及风险评价[J]. 天津大学学报, 2009, 42(12):1112-1117. PENG X, YE L L, WANG C H, et al. Temperature and duration-dependent rice straw-derived biochar:characteristics and its effects on soil properties of an Ultisol in southern China[J]. Soil and Tillage Research, 2011, 112(2):159-166. 沈伯雄, 张增辉, 李力, 等. 热解终温对污泥热解残渣特性的影响[J]. 环境污染与防治, 2011, 33(2):22-26. 高凯芳, 简敏菲, 余厚平, 等. 裂解温度对稻秆与稻壳制备生物炭表面官能团的影响[J]. 环境化学, 2016, 35(8):1663-1669. YUAN H R, TAO L, HUANG H Y, et al. Influence of pyrolysis temperature on physical and chemical properties of biochar made from sewage sludge[J]. Journal of Analytical and Applied Pyrolysis, 2015, 112:284-289. SONJA S, BRUNO G. One step forward toward characterization:some important material properties to distinguish biochars[J]. Journal of Environmental Quality, 2012, 41(4):1001-1013. 王定美,王跃强,余震等. 污泥与稻秆共热解对生物炭中碳氮固定的协同作用[J]. 环境科学学报, 2015, 35(7):2202-2209. 吕丰锦, 刘俊新. 我国南北方城市污水处理厂污泥性质比较分析[J]. 给水排水, 2016, 42(增刊1):63-65. LU H L, ZHANG W H, WANG S Z, et al. Characterization of sewage sludge-derived biochars from different feedstocks and pyrolysis temperatures[J]. Journal of Analytical and Applied Pyrolysis, 2013, 102:137-143. LU T, YUAN H R, ZHOU S G, et al. On the Pyrolysis of Sewage Sludge:the Influence of Pyrolysis Temperature on Biochar, Liquid and Gas Fractions[M]. Switzerland:Trans Tech-Publ, 2012:3412-3420. AREEPRASERT C, ZHAO P, MA D. Alternative solid fuel production from paper sludge employing hydrothermal treatment[J]. Energy & Fuels, 2014, 28(2):1198-1206. QZCIMEN D, ERSOY-MERIBOYU A. Characterization of biochar and bio-oil samples obtained from carbonization of various biomass materials[J]. Renewable Energy, 2010, 35(6):1319-1324. HE C, GIANNIS A, WANG J Y. Conversion of sewage sludge to clean solid fuel using hydrothermal carbonization:hydrochar fuel characteristics and combustion behavior[J]. Applied Energy, 2013, 111:257-266. ZHOU G L, WU J J, MIAO Z Y, et al. Effects of process parameters on pore structure of semi-coke prepared by solid heat carrier with dry distillation[J]. International Journal of Mining Science and Technology, 2013, 23(3):423-427. PAZ-FERREIRO J, GASCÓ G, GUTIÉRREZ B, et al. Soil biochemical activities and the geometric mean of enzyme activities after application of sewage sludge and sewage sludge biochar to soil[J]. Biology and Fertility of Soils, 2011, 48(5):511-517. WAQAS M, LI G, KHAN S, et al. Application of sewage sludge and sewage sludge biochar to reduce polycyclic aromatic hydrocarbons(PAH) and potentially toxic elements (PTE) accumulation in tomato[J]. Environmental Science and Pollution Research International, 2015, 22(16):12114-12123. DEVI P, SAROHA A K. Effect of pyrolysis temperature on polycyclic aromatic hydrocarbons toxicity and sorption behaviour of biochars prepared by pyrolysis of paper mill effluent treatment plant sludge[J]. Bioresource Technology, 2015, 192,312-320. 陈宝梁, 周丹丹, 朱利中,等. 生物碳质吸附剂对水中有机污染物的吸附作用及机理[J]. 中国科学(B辑:化学), 2008,38(6):530-537. 王兴栋, 张斌, 余广炜,等.不同粒径污泥热解制备生物炭及其特性分析[J]. 化工学报, 2016, 67(11):4808-4816. 杨招艺, 陶家林, 王瑞露, 等.热解温度对污泥碳基材料表面性质及吸附性能的影响[J].环境工程学报,2019,13(11):2711-2721. 郑凯琪, 王俊超, 刘姝彤, 等. 不同热解温度污泥生物炭对Pb2+、Cd2+的吸附特性[J]. 环境工程学报, 2016, 10(12):7277-7282. HOSSAIN M K, STREZOV V, CHAN K Y, et al. Influence of pyrolysis temperature on production and nutrient properties of wastewater sludge biochar[J]. Journal of Environmental Management, 2011, 92:223-228. ZIELIN'SKA A, OLESZCZUK P. The conversion of sewage sludge into biochar reduces polycyclic aromatic hydrocarbon content and ecotoxicity but increases trace metal content[J]. Biomass and Bioenergy, 2015, 75:235-244. VAN WESENBEECK S, PRINS W, RONSSE F, et al. Sewage sludge carbonization for biochar applications:fate of heavy metals[J]. Energy & Fuels, 2014, 28(8):5318-5326. TYTLAK A, OLESZCZUK P, DOBROWOLSKI R. Sorption and desorption of Cr (Ⅵ) ions from water by biochars in different environmental conditions[J]. Environmental Science and Pollution Research International, 2015, 22(8):5985-5994. 于晓庆, 董滨, 何群彪, 等. 污水污泥和消化污泥热解过程中重金属迁移转化行为对比分析[J]. 净水技术, 2017, 36(12):27-32. SHI W S, LIU C G, DING D H, et al. Immobilization of heavy metals in sewage sludge by using subcritical water technology[J]. Bioresource Technology, 2013, 137:18-24.
点击查看大图
计量
- 文章访问数: 175
- HTML全文浏览量: 22
- PDF下载量: 11
- 被引次数: 0