载铈凝胶型离子交换树脂/H_(2)O_(2)体系去除水中As(Ⅲ)特性  

Efficient removal of As(Ⅲ) from water by a nanocomposite of nanoceria confined in a gel-type anion exchanger in the presence of H_(2)O_(2)

作　　者：黄宇豪 单超[1,2] 张炜铭[1,2] 潘丙才[1,2] HUANG YuHao;SHAN Chao;ZHANG WeiMing;PAN BingCai(State Key Laboratory of Pollution Control and Resource Reuse,School of Environment,Nanjing University,Nanjing 210023,China;Research Center for Environmental Nanotechnology(ReCENT),Nanjing University,Nanjing 210023,China)

机构地区：[1]南京大学环境学院,污染控制与资源化研究国家重点实验室,南京210023 [2]南京大学环境纳米技术研究中心,南京210023

出　　处：《中国科学：技术科学》2021年第12期1530-1540,共11页Scientia Sinica(Technologica)

基　　金：国家自然科学基金(批准号:51878332);中央高校基本科研业务费专项资金(编号:14380177);江苏省自然科学基金(编号:BK20160653)资助项目。

摘　　要：地下水砷污染是重要的全球性环境问题.As(Ⅲ)是地下水中砷的主要价态,通常以电中性分子形式存在,难以通过常规水处理工艺有效去除.将As(Ⅲ)预氧化为As(V)再进一步吸附处理是高效除砷的有效策略.本文通过前体导入-原位沉淀法制备了兼具催化H_(2)O_(2)氧化和吸附功能的载铈凝胶型阴离子交换树脂纳米复合材料Ce-201×4,探究了Ce-201×4/H_(2)O_(2)体系去除As(Ⅲ)的特性和过程.XRD和SEM-EDS等表征表明,Ce-201×4负载的纳米铈氧化物主要为无定形,呈环状立体分布,负载后树脂的比表面积和孔容均增加了约33倍.静态批次实验表明,Ce-201×4/H_(2)O_(2)体系去除As(Ⅲ)吸附容量为121.4 mg/g,相较无H_(2)O_(2)的单一吸附体系提高了5.1倍,且Ce-201×4在有/无H_(2)O_(2)体系中吸附量均高于载铈大孔型离子交换树脂纳米复合材料Ce-D201.Ce-201×4/H_(2)O_(2)体系去除As(Ⅲ)效率随pH上升而提高,与H_(2)O_(2)在碱性条件下直接氧化As(Ⅲ)效率提高有关.Ce-201×4/H_(2)O_(2)体系除As(Ⅲ)抗硅酸盐干扰性能略优于Ce-D201/H_(2)O_(2)体系.静态再生实验表明,Ce-201×4/H_(2)O_(2)除As(Ⅲ)后材料再生性能良好,适宜长期循环使用.XPS分析表明,Ce-201×4/H_(2)O_(2)体系去除As(Ⅲ)的机理主要包括纳米氧化铈催化H_(2)O_(2)将As(Ⅲ)氧化为As(V)并通过离子交换和专属吸附等作用从水中进一步去除的过程.Arsenic(As) pollution of groundwater is a serious environmental problem worldwide.As is usually present as As(Ⅲ) in groundwater.Conventional methods of removal of As(Ⅲ) are usually inefficient because of the charge neutrality and the high mobility of H_(3)AsO_(3).Pre-oxidizing As(Ⅲ) into As(V) has been regarded as an effective strategy for As(Ⅲ) removal.In this study,a millimeter-sized nanocomposite Ce-201×4 was fabricated by employing a gel-type anion exchanger 201×4 as a host through precursor loading followed by in-situ precipitation.The performance of Ce-201×4 in removing As(Ⅲ) was studied in both the absence and the presence of H_(2)O_(2).The characterization results,including XRD and SEM-EDS,indicated that the nanoceria immobilized in Ce-201×4 was mainly amorphous and showed a peripheral shell-like distribution within the composite bead.The specific surface area and pore volume of the nanocomposite increased by 33 times relative to the host.Batch experiments revealed the adsorption capacity of Ce-201×4/H_(2)O_(2) for As(Ⅲ) to be 121.4 mg/g,5.1 times higher than that in the absence of H_(2)O_(2).Furthermore,both in the absence and presence of H_(2)O_(2),the adsorption capacity of Ce-201×4 for As(Ⅲ) was larger than was that of Ce-D201,which was prepared with the macroporous counterpart as the host.As(Ⅲ) removal by Ce-201×4/H_(2)O_(2) was promoted by the increase of pH,which could be attributed to increased reactivity of As(Ⅲ) oxidation by H_(2)O_(2) under alkaline conditions.The As(Ⅲ) removal performance of Ce-201×4/H_(2)O_(2) was slightly higher than was that of Ce-D201/H_(2)O_(2) in the presence of silicate.A static regeneration experiment revealed that Ce-201×4 had potential for long-term recycling in the presence of H_(2)O_(2).XPS analysis showed that the removal of As(Ⅲ) by Ce-201×4/H_(2)O_(2) mainly included the catalytic oxidation of As(Ⅲ) by H_(2)O_(2) over nanoceria and the further removal of the resultant As(V)through ion-exchange and specific adsorption.

关 键 词：地下水除砷 纳米复合材料 耦合型功能材料 催化氧化 吸附 

分 类 号：X523[环境科学与工程—环境工程]