海藻酸钠负载硫化零价铁对水体中Cr(Ⅵ)的还原去除  

Sodium Alginate Loading of Zero-Valent Iron Sulfide for the Reduction of Cr(Ⅵ)in Water

作　　者：王旭[1] 杨欣楠 黄币娟 刘壮 牟诗萌 程敏[1] 谢燕华[1,2] WANG Xu;YANG Xin-nan;HUANG Bi-juan;LIU Zhuang;MU Shi-meng;CHENG Min;XIE Yan-hua(College of Ecology and Environment,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]成都理工大学生态环境学院,成都610059 [2]成都理工大学地质灾害防治与地质环境保护国家重点实验室,成都610059

出　　处：《环境科学》2021年第6期2908-2916,共9页Environmental Science

基　　金：国家自然科学基金项目(41977170);四川省科技厅重大科技专项(2018SZDZX0020)。

摘　　要：本研究以微米零价铁(ZVI)为核心,对ZVI进行硫化改性和海藻酸钠(SA)负载,成功制备一种高效去除Cr(Ⅵ)的功能性材料(SZVI-SA).考察了材料制备过程中螯合剂种类、质量分数、S/Fe等参数对Cr(Ⅵ)去除的影响.采用SEM-EDS、TEM、XRD和XPS等对材料进行表征分析,讨论去除机制.实验结果表明,选择7%的Fe^(3+)为海藻酸钠螯合剂,S/Fe=3.5、干燥温度70℃作为材料制备的较优条件;SZVI-SA对Cr(Ⅵ)的去除过程符合准二级动力学模型,吸附速率主要受Cr(Ⅵ)与SZVI-SA结合位点之间的化学反应速率控制.表征结果表明,SZVI-SA有效成分为Fe S,比表面积较大为97.83 m^(2)·g^(-1),以微孔为主,孔隙较多.SZVI-SA对Cr(Ⅵ)的还原去除率可达92%,同时能有效地去除反应后溶液中的Cr(Ⅲ)和Fe(Ⅲ).SZVI-SA与Cr(Ⅵ)的反应机制主要为氧化还原反应,主要还原活性物质为Fe^(2+)、S_(2)-和S_(2)^(2-);反应后生成的Fe(Ⅲ)和Cr(Ⅲ)最终以Fe(OH)_(3)、Cr(OH)_(3)和Cr2O_(3)的形式沉淀分离.In this study,the functional material SZVI-SA is successfully prepared to efficiently remove Cr(Ⅵ)from water.This composite,with micron zero-valent iron(ZVI)as its core,is sulfurized and loaded by sodium alginate(SA).Some parameters affecting the Cr(Ⅵ)removal are also tested,including the type and mass fraction of chelating agents as well as S/Fe.SEM-EDS,TEM,XRD,and XPS are used to characterize and analyze the material.The results show that 7%Fe^(3+)is most suitable as the chelating agent for sodium alginate,and a S/Fe ratio of 3.5 and drying temperature of 70℃are the ideal formation conditions.The effect of SZVI-SA on the removal of Cr(Ⅵ)is in line with the secondary adsorption rate model,mainly affected by the availability of binding sites.The active ingredient was identified as Fe S,and the specific surface area can reach 97.83 m^(2)·g^(-1).Many pores,especially micropores,are present in this material and in addition to Cr(Ⅵ),SZVI-SA was found to effectively remove Cr(Ⅲ)and Fe(Ⅲ)from the test solution.Overall,the Cr(Ⅵ)-removal efficiency was 92%;the removal mechanism is mainly via redox reactions;and the main reducing active substances are Fe^(2+),S_(2)-,and S_(2)2-.Following the reaction of Fe(Ⅲ)and Cr(Ⅲ),Fe(OH)_(3) and Cr(OH)_(3) are formed and Cr2O_(3) precipitation separation occurs.

关 键 词：六价铬[Cr(Ⅵ)] 海藻酸钠 硫化零价铁 还原 机制 

分 类 号：X703.1[环境科学与工程—环境工程]