摘要
采用新型固化剂对重金属Pb、Cd、Cu复合污染土进行固化/稳定化处理。为探究其机理,该文对固化土的重金属形态、浸出毒性及微观结构进行了检测。结果表明,随着固化剂掺量的增加,重金属的浸出浓度降低,固化剂掺量为10%时,Pb、Cd、Cu的浸出浓度均低于《危险废物鉴别标准浸出毒性鉴别》(GB 5085.3-2007)限值,固化/稳定化后重金属污染土的无侧限抗压强度达4.1 MPa,可用作路基填料。经固化/稳定化处理后,重金属的存在形态从弱酸提取态向更加稳定的残渣态转化。固化/稳定化过程中生成水化硅酸钙和钙矾石,对固化土内部结构起填充作用,可改善固化土强度。通过物理包裹、沉淀、吸附及离子置换作用,新型固化剂对重金属离子产生固化/稳定化作用,该技术可用于实际重金属复合污染土的处理。
Pb, Cd and Cu compound contaminated soil was solidified by the new curing agent. In order to explore its mechanism, the heavy metal form, leaching toxicity and microstructure of the solidified soil were tested. The results showed that the leaching concentration of heavy metals decreased with the increasing of the curing agent dosage. When the curing agent dosage is 10%, the leaching concentrations of Pb, Cd and Cu are all lower than the Identification Standard for Hazardous Wastes-Identification for Extraction Toxicity(GB 5085.3-2007) limit. The unconfined compressive strength of heavy metal contaminated soil after solidification reach 4.1 MPa, which can be used as roadbed filler. After the solidification treatment, the existence of heavy metals change from the weak acid extraction state to the residue state. During the solidification process, calcium silicate hydrate and ettringite are generated, which fill the internal structure of the solidified soil and improve the strength of the solidified soil. Through physical package, precipitation, adsorption and ion replacement, the heavy metal ions are solidified by the new curing agent. This technology can be used to solidify the actual heavy metal compound contaminated soil.
作者
程爱华
程岩
刘伟
李昊
李晓军
CHENG Aihua;CHENG Yan;LIU Wei;LI Hao;LI Xiaojun(College of Geology and Environment,Xi'an University of Science and Technology,Xi’an 710054,China;Shaanxi Provincial Land Engineering Construction Group Co.,Ltd,Xi’an 710075,China)
出处
《环境科学与技术》
CAS
CSCD
北大核心
2021年第10期83-88,共6页
Environmental Science & Technology
基金
陕西省教育厅服务地方专项科学研究计划(20JC026)
陕西省土地工程建设集团有限责任公司内部科研项目(DJNY2020-11)。
关键词
重金属复合污染土
固化/稳定化
浸出浓度
重金属形态
机理
heavy metal compound contaminated soil
solidification/stabilization
leaching concentration
heavy metal forms
mechanism
作者简介
程爱华(1977-),女,副教授,博士,主要从事环境污染治理研究,(电子信箱)cah_cheng@126.com。
