固体浓度对污染底泥中重金属生物沥浸去除效果的影响  

Effect of Total Solids Concentration on Heavy Metals Bioleaching from Contaminated Sediment

作　　者：赵亮[1,2] 方迪[1,2] 单红仙[1,2] 贾永刚[1,2] 

机构地区：[1]中国海洋大学海洋环境与生态教育部重点实验室,青岛266100 [2]中国海洋大学环境科学与工程学院,青岛266100

出　　处：《环境科学》2009年第8期2347-2352,共6页Environmental Science

基　　金：国家自然科学基金项目(20707024)

摘　　要：采用序批式摇床,研究了固体浓度为3%-13%的底泥浓度对生物沥浸法去除污染底泥中重金属（Zn、Cu和Cr）的影响.结果表明,随着固体浓度增加,底泥pH值下降和ORP上升速率减缓,重金属的沥浸去除速率相应降低;沥浸过程中,当底泥pH值由5.0降至2.0,ORP由200 mV升至520 mV时,重金属的去除率增加最为迅速;不同浓度的处理,沥浸12 d,Zn、Cu和Cr的去除率分别为60%-85%、65%-100%和17%-35%.试验发现,底泥沥浸中pH值随时间的变化符合Boltzmann方程,此方程可估算底泥酸化进程.连续提取法对脱毒（沥浸）底泥中残留Zn、Cu和Cr的形态分级显示,底泥中未沥浸去除的重金属绝大部分以残渣态存在,环境风险较低.从经济角度考虑,固体浓度10%在底泥沥浸的实际应用中较为合适.The effect of total solids concentration on heavy metals bioleaching from contaminated sediment was investigated in shake flasks. The results demonstrated that an increase in total solids concentration reduced the rates of sediment pH reduction, ORP increase and metal removal. During this bioleaching process, the removal of Zn, Cu, and Cr rapidly enhanced and then gradually approached the maximum removal efficiency when sediment pH decreased from 5.0 to 2.0 and the ORP increased from 200 mV to 520 mV. After 12 days of bioleaching, about 60%-85% of Zn, 65%-100% of Cu, and 17%-35% of Cr could be removed from various sediments of 3%-13% solids content, respectively. It was found that the variation of sediment pH in this bioleaching process could be estimated by a modified Boltzmann model. The analysis of speciation distribution of metals indicated that the unremoved Cu, Zn, and Cr in the bioleached sediment mainly existed in residual fraction, and that the percentages of Cu, Zn, and Cr bound to this fraction were 76.2%, 81.2%, and 82.7%, respectively. From economical consideration, the recommended total solids concentration for the bioleaehing of metals from the sediment is 10% .

关 键 词：污染底泥 生物沥浸 硫氧化细菌 重金属 固体浓度 

分 类 号：X705[环境科学与工程—环境工程]