摘要
土壤Cd污染已成为我国的主要环境问题,严重威胁着农业的可持续发展,因此,亟需探索经济、有效的土壤修复技术.采用共沉淀法制备超顺磁性纳米Fe_(3)O_(4)@SiO_(2)功能化材料(MFS),以此为修复剂并磁选回收去除土壤中的Cd,考察了MFS投加量、修复时间、土壤pH、土壤Cd含量和土壤有机质含量对MFS修复Cd污染土壤的影响,并探讨了有机酸活化联合MFS修复对实际农田土壤中Cd的去除效果.结果表明,对于总Cd含量为2.348 mg·kg^(-1)的土壤,随着MFS投加量的增加,土壤总Cd和有效态Cd含量均呈下降趋势;当MFS投加量为1.5%(材料∶土壤,质量比)时,土壤总Cd和有效态Cd含量分别下降23.21%和31.59%.土壤总Cd和有效态Cd含量均随修复时间的延长而降低,修复30 d时土壤总Cd和有效态Cd含量分别下降24.07%和35.94%;投加MFS可以显著降低土壤酸溶态和还原态Cd含量,氧化态Cd含量也有一定程度下降.土壤pH对去除土壤Cd有较大影响,在酸性土壤中Cd去除率较高.随着土壤Cd污染程度的加重,MFS对Cd去除率逐渐升高并趋于稳定;当土壤总Cd含量为0.882、1.267、1.653、2.348、3.717和5.751 mg·kg^(-1)时,Cd去除率分别为16.27%、17.58%、19.62%、22.47%、21.63%和21.52%;土壤有机质含量增加会抑制材料对Cd的去除.有机酸活化联合MFS修复能够显著提高土壤总Cd和有效态Cd的去除效果,其中,柠檬酸活化的效果略好于酒石酸.MFS去除土壤Cd的主要机制包括配位反应和磁力作用.
Soil Cd pollution has become a major environmental problem in China,which poses a serious threat to the sustainable development of agriculture,and it is urgent to explore economic and effective soil remediation technology.In this work,a superparamagnetic Fe_(3)O_(4)@SiO_(2) functionalized material(MFS)was prepared by coprecipitation method,which was used as a remediator to remove Cd from the soil by magnetic selection recycling,and the effects of MFS dosage,remediation time,soil pH,soil Cd content and soil organic matter content on the remediation of Cd-contaminated soil were examined,and the removal efficiency of Cd in actual farmland soil was also investigated by organic acid activation combining with MFS remediation.For the soil with total Cd content of 2.348 mg·kg^(-1),soil total Cd and available Cd contents showed a decreasing trend with the increase of MFS dosage,and they decreased by 23.21%and 31.59%when MFS dosage was 1.5%(material:soil),respectively.Moreover,soil total Cd and available Cd contents decreased with the extension of remediation time,they decreased by 24.07%and 35.94%for 30 d remediation,respectively.MFS addition could significantly lower soil acid-soluble and reduced Cd contents,and also decrease soil oxidized Cd content to some extent.Soil pH had a great influence on the removal of Cd in soil,and high removal efficiency could be obtained in acidic soil.With the aggravation of soil Cd pollution,the removal efficiency of Cd by MFS increased gradually and then tended to be stable.For the soils with total Cd content of 0.882,1.267,1.653,2.348,3.717 and 5.751 mg·kg^(-1),the removal efficiencies of Cd were 16.27%,17.58%,19.62%,22.47%,21.63%and 21.52%,respectively.In addition,increased soil organic matter content could inhibit Cd removal by the material.Especially,organic acid activation combined with MFS remediation could significantly improve the removal of soil total Cd and available Cd,and citrate acid activation was found to be better than tartaric acid activation.The removal mechanisms of soil Cd by MFS may include coordination reaction and magnetic action.
作者
孙圆鹏
易平
张立志
方丹丹
黎洁
王强
SUN Yuanpeng;YI Ping;ZHANG Lizhi;FANG Dandan;LI Jie;WANG Qiang(College of Resources and Environment,Southwest University,Chongqing 400716;Chongqing Key Laboratory of Agricultural Resources and Environment Research,Chongqing 400716;Chongqing Wanzhou District Communications Bureau,Chongqing 404100)
出处
《环境科学学报》
CAS
CSCD
北大核心
2022年第6期386-397,共12页
Acta Scientiae Circumstantiae
基金
国家重点研发计划项目(No.2017YFD0801005)。
