铁氧化物-硅酸盐复合物的形成、性质及其对砷的固定  

Formation,properties and the fixation in arsenic of iron(hydr)oxide-phyllosilicate complexes

作　　者：杨忠兰 曾希柏[1] 孙本华[2] 苏世鸣[1] 王亚男[1] 张楠 张洋 吴翠霞[1] YANG Zhong-lan;ZENG Xi-bai;SUN Ben-hua;SU Shi-ming;WANG Ya-nan;ZHANG Nan;ZHANG Yang;WU Cui-xia(Institute of Environment and Sustainable Development in Agriculture,Chinese Academy of Agriculture Sciences,Key Laboratory of Agro-Environment of Ministry of Agriculture and Rural Affairs,Beijing 100081,China;College of Natural Resources and Environment,Northwest A&F University,Yangling,Shaanxi 712100,China)

机构地区：[1]中国农业科学院农业环境与可持续发展研究所/农业农村部农业环境重点实验室,北京100081 [2]西北农林科技大学资源环境学院,陕西杨凌712100

出　　处：《农业现代化研究》2021年第2期294-301,共8页Research of Agricultural Modernization

基　　金：国家自然科学基金区域创新发展联合基金项目(U19A2048);中国农业科学院科技创新工程专项(CAAS-ASTIP-2016-IEDA)。

摘　　要：铁氧化物与硅酸盐矿物是土壤中最重要、最活跃的固相组分,它们之间的交互作用直接影响土壤物理化学特性,可有效地调控土壤(类)重金属的迁移、转化。本文以铁氧化物和硅酸盐矿物胶结过程中的一些表观特征变化为出发点,从宏观、表观到微观综述了二者交互作用的界面特性和机理、交互作用前后对土壤砷的固定与释放机制等内容。本文阐明层状硅酸盐与铁氧化物通过多种化学作用而发生表面复合,其中静电作用是作用力之一,带负电荷的硅酸盐与带正电荷的铁氧化物在静电引力的作用下迅速结合,在胶体表面双电层上形成二元团聚体;形成的二元团聚体可改变土壤矿物的表面积和孔性结构、表面电化学特性和物理性质。同时,铁氧化物-硅酸盐复合物表面的活性基团可以通过内层络合共氧的方式将土壤中AsO_(4)^(2-)络合,形成单核或双核表面络合物而固定砷。复合物对AsO_(4)^(2-)的吸附能力介于铁氧化物和硅酸盐矿物之间,并更接近铁氧化物的表面吸附特性。本文旨在为土壤砷的原位固定提供理论支撑。Iron(hydr)oxides and phyllosilicate minerals are the most important and active solid phase components in the soil.The interaction between them directly affects the physico-chemical properties of soil,which can effectively control the migration and transformation of heavy metals(submetals)in soil.The review is started with the changes of iron oxide and phyllosilicate minerals in the apparent characteristics during the cementation process,followed by a review of the interaction mechanisms and interfacial characteristics between the two components from macroscopic,apparent to microscopic level,with the discussion of arsenic fixation and release mechanism in soil before and after the interaction.This article clarifies the fact that phyllosilicate minerals and iron oxide undergo surface complex through a variety of chemical interactions.Electrostatic interaction,as one of the key mechanisms for the above-mentioned interaction,involves the rapid combination of the negatively charged phyllosilicate minerals and the positively charged iron(hydr)oxides under the electrostatic attraction,forming a binary agglomerate on the double layer of the colloid surface.The formed binary agglomerate can change the surface area,pore structure surface electrochemical properties and physical properties of soil minerals.At the same time,the active groups on the surface of the iron(hydr)oxidephyllosilicate complexes can fix the AsO_(4)^(2-)in the soil through the formation of inner layer complexes by sharing oxygen atoms,which means the formation of mononuclear or binuclear surface complex with the fixed arsenic.The adsorption capacity for AsO_(4)^(2-)of the iron(hydr)oxide-phyllosilicate complex is between iron(hydr)oxides and phyllosilicate minerals,while the surface adsorption characteristics of the complex are similar to that of iron(hydr)oxide.This article aims to provide theoretical support for the in-situ fixation of arsenic in soil.

关 键 词：铁氧化物 层状硅酸盐矿物 交互作用 复合物 砷 吸附 共沉淀 

分 类 号：X53[环境科学与工程—环境工程]