壳聚糖改性钠基膨润土稳定剂对重金属污染底泥的处理  

Treatment of heavy metal polluted sediment with chitosan modified Nabentonite stabilizer

作　　者：刘丁玮 王春荣[1] 赵明川 韩璐瑞 韩善萌 柯述 韩港胜 董滨[2] 李攀 LIU Dingwei;WANG Chunrong;ZHAO Mingchuan;HAN Lurui;HAN Shanmeng;KE Shu;HAN Gangsheng;DONG Bin;LI Pan(School of Chemical and Environmental Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;College of Environmental Science and Engineering,Tongji University,Shanghai 200082,China)

机构地区：[1]中国矿业大学(北京)化学与环境工程学院,北京100083 [2]同济大学环境科学与工程学院,上海200082

出　　处：《环境工程学报》2022年第12期3906-3915,共10页Chinese Journal of Environmental Engineering

基　　金：国家重点研发计划项目(2020YFC1908703-02)。

摘　　要：为有效处理重金属污染的疏浚底泥并验证重金属稳定剂的稳定性,采用重金属稳定化的方法,以Cu^(2+)、Zn^(2+)、Cd^(2+)单一和复合重金属污染的疏浚底泥为研究对象,以壳聚糖改性后的钠基膨润土为稳定剂,在不同稳定剂投加量、pH和液固比的条件下,对污染底泥进行稳定化处理,并采用毒性特征沥滤方法(TCLP)和BCR连续提取法对稳定化效果进行分析与评价。结果表明:经过壳聚糖改性后的钠基膨润土稳定重金属的能力显著提高,在投加量为5%时,对Cu^(2+)、Zn^(2+)、Cd^(2+)单一重金属污染底泥便可达到较高的稳定化率;聚糖改性钠基膨润土稳定剂(NaBent-CTS)处理Cu^(2+)、Zn^(2+)、Cd^(2+)单一重金属污染底泥的最佳投加量为5%~7%,pH为6~7,液固比为1.3:1~1.7:1;NaBent-CTS处理Cu^(2+)、Zn^(2+)、Cd^(2+)复合重金属污染底泥的最佳投加量为5%、pH为7、液固比为1.5:1,稳定化率分别达到75.95%、73.71%和59.00%;NaBent-CTS处理复合重金属污染底泥时重金属存在竞争吸附,由强到弱排列顺序为Cu^(2+)>Zn^(2+)>Cd^(2+);经NaBent-CTS稳定化处理14 d后,可氧化态和残渣态占比显著提高,稳定性能佳。NaBent-CTS对Cu^(2+)、Zn^(2+)、Cd^(2+)单一和复合重金属污染底泥具有较好的稳定效果。该研究结果可为重金属污染疏浚底泥的稳定化处理提供相关参考。In order to effectively treat the dredged sediment polluted by heavy metals and verify the stability of heavy metal stabilizer,a type of heavy metal stabilization method with the stabilizer of the Na-bentonite modified by chitosan was adopted,the dredged sediment polluted by single and complex heavy metals Cu^(2+),Zn^(2+)and Cd^(2+)was taken as the research object to perform the stabilizing treatment under the conditions of different stabilizer dosage,pH and liquid-solid ratio.Toxicity characteristic leaching method(TCLP)and BCR continuous extraction method were used to analyze and evaluate the stabilization effect.The results showed that the ability of Na-bentonite modified by chitosan to stabilize heavy metals increased significantly.When the dosage of sodium bentonite modified by chitosan was 5%,the sediment contaminated by single heavy metal of Cu^(2+),Zn^(2+)or Cd^(2+)could reach a high stabilization rate.The optimal dosage of Na-bentonite stabilizer(NaBentCTS)treating contaminated sediments by Cu^(2+),Zn^(2+)and Cd^(2+)alone was 5%~7%,pH was 6~7 and the liquid-tosolid ratio was 1.3:1~1.7:1.The optimal dosage of NaBent-CTS treating contaminated sediment by Cu^(2+),Zn^(2+)and Cd^(2+)composite heavy metals was 5%,pH was 7 and liquid-to-solid ratio was 1.5:1,and the stabilization rates were 75.95%,73.71%and 59.00%,respectively.The competitive adsorption of heavy metals occurred in NaBent-CTS treatment process,and the corresponding competitive order from strong to weak was Cu^(2+)>Zn^(2+)>Cd^(2+).After 14 days of NaBent-CTS stabilization treatment,the proportions of oxidizable state and residue state for heavy metals increased significantly,and heavy metal stability was good.NaBent-CTS has good stabilization effects on sediment polluted by single and complex heavy metals of Cu^(2+),Zn^(2+)and Cd^(2+).The results can provide a relevant reference for the stabilization treatment of dredged sediment polluted by heavy metals.

关 键 词：壳聚糖 钠基膨润土 稳定剂 重金属 底泥 

分 类 号：X524[环境科学与工程—环境工程]