摘要
垃圾焚烧飞灰中的重金属浸出能力强、毒性大,属于危险废物,若处置不当将会对环境造成严重污染。采用酸洗-电沉积联用技术,考察硝酸浓度、液固比和酸洗时间对重金属去除率的影响,研究电沉积电压和时间对酸洗废液中重金属回收率的影响,同时评估处理后飞灰的浸出毒性。结果表明,在浓度为2 mol·L^(-1)、液固比为25的硝酸中浸渍洗涤60 min条件下,酸洗能成功去除飞灰中95.26%的Zn、83.06%的Pb、72.62%的Cu和97.85%的Cd;在电压为14 V,电沉积4 h的条件下可回收酸洗废液中95.80%的Zn、99.04%的Pb、79.95%的Cu和90.37%的Cd。对Zn、Pb、Cu、Cd的连续提取和浸出毒性测试表明,处理后飞灰易浸出组分占比降低,残余态物质占比提高,重金属浸出质量浓度符合《生活垃圾填埋场污染控制标准》(GB 16889-2008)要求,可直接进行填埋或作为非危废固体进行资源化利用。本研究结果可为飞灰中重金属脱除和回收利用提供参考。
The municipal solid waste incineration fly ash is classified as hazardous waste and will cause serious pollution to the environment if disposed improperly,owing to its strong leaching ability and high toxicity of heavy metals.Herein,the combined acid washing and electrodeposition technology was used to study the effects of the nitric acid concentration,liquid-solid mass ratio,acid washing time on the removal rate of heavy metals,and the effects of electrodeposition voltage and time on the recovery rate of the heavy metals from the acid washing waste solution,as well as to evaluate the leaching toxicity of the treated fly ash.The results showed that 95.26%of Zn,83.06%of Pb,72.62%of Cu and 97.85%of Cd were successfully removed from fly ash after immersing and washing for 60 min in nitric acid with concentration of 2 mol·L^(−1)and liquid-to-solid ratio of 25.Meanwhile,95.80%of Zn,99.04%of Pb,79.95%of Cu and 90.37%of Cd in the acid washing waste solution were recovered at a voltage of 14 V and 4 h of electrodeposition.The continuous extraction and leaching toxicity tests of Zn,Pb,Cu and Cd demonstrated that the content of easily leachable components of the washed fly ash decreased,the proportion of residual state materials increased,and the leaching mass concentration of heavy metals met the requirements of“Pollution Control Standards for Domestic Waste Landfills”(GB 16889-2008),as thus,the acid washed fly ash can be directly landfilled or used as a non-hazardous waste solid for resource utilization.This study can provide a reference for the removal and recovery of heavy metals from fly ash.
作者
刘嘉豪
马红钦
谷星朋
LIU Jiahao;MA Hongqin;GU Xingpeng(School of Chemical Engineering and Technology,Tianjin University,Tianjin 300072,China;Tianjin Key Laboratory of Chemical Process Safety and Equipment Technology,Tianjin 300072,China)
出处
《环境工程学报》
CAS
CSCD
北大核心
2023年第5期1580-1588,共9页
Chinese Journal of Environmental Engineering
关键词
垃圾焚烧飞灰
酸洗
电沉积
危险废物
重金属
municipal solid waste incineration fly ash
acid washing
electrodeposition
hazardous waste
heavy metals
