蒙脱石黏土矿物环境材料构建的研究进展

Research Progress in Construction of MontmorilloniteEnvironmental Mineral Materials

蒙脱石是一种黏土矿物,具有纳微米级粒径、大比表面积、特殊的纳米层间域、层间离子可交换性等物化性质,且分布广泛、储量丰富、价格低廉,可作为一种良好的环境材料用于对污水中各类污染物的吸附去除。蒙脱石对重金属、放射性核素,以及磷酸根等离子有较好的吸附能力。由于其表面极强的亲水性,蒙脱石矿物对弱极性和非极性有机污染物的吸附性能较差,限制了其应用范围。大量研究者选取适当的表面活性剂、硅烷偶联剂,通过插层、嫁接及柱撑等表面改性和结构改型处理,不仅大大提高其对无机离子的吸附能力,还可将蒙脱石亲水性表面变为疏水亲油表面,改变其表面张力与接触角,极大提升其对有机污染物的吸附性能。目前,对蒙脱石黏土矿物表面反应性的研究(包括黏土矿物的表面改性、层间域改造)已引起广泛关注,研究者通过不断寻求新技术、新方法,以扩展蒙脱石环境材料应用的广度和深度。利用离子交换、插层、柱撑、层间聚合等各种处理方法,把其他离子或化合物引入蒙脱石层间域,对其进行结构与表面性质的调控,使其表-界面物理化学性质发生相应的变化,制得具有不同功能性质的新型材料,可作为污染物的吸附剂、催化剂、混凝剂等广泛应用于环境污染修复领域。本文综述了近年来一些主要的蒙脱石矿物环境材料的构建方法及进展,探讨其微观结构对吸附性能的影响,阐述黏土矿物结构与吸附性能之间的构效关系,为开发新型高效环保的黏土矿物环境材料提供借鉴。

Montmorillonite(Mnt)is a clay mineral with excellent physical and chemical properties such as nano-micron particle size,large specific surface area,special nano-layer interlayer space,and exchangeability of cations in the interlayer.It is widely distributed,abundant in reserves and low in price.Mnt is thus a good environmental material that can be used for the adsorption and removal of various pollutants in the sewage.Such as heavy metals,radionuclides,and phosphate ions,Mnt has good adsorption capacity for them.However,Mnt has poor adsorption pro-perties for weakly polar and non-polar organic pollutants due to its extremely strong hydrophilic nature,which limits its application range.A large number of researchers modified the surface properties of Mnt by intercalating,grafting and/or pillaring Mnt using suitable surfactants,silane coupling agents.These treatments not only greatly improved the adsorption capacity of Mnt for inorganic ions,but also converted its hydrophilic surface into a hydrophobic surface and changed the surface tension and contact angle.Therefore,surface modification of Mnt greatly improving its adsorption performance for organic pollutants.At present,the studies on the surface reactivity of Mnt,including surface and interlayer modification,have attracted wide attention.Researchers are continually creating new technologies and methods to expand the breadth and depth of the Mnt environmental material application.Cation exchange,intercalation,pillaring,interlayer polymerization and other treatments are used to introduce other ions or compounds into the Mnt interlayer.The modification of the structure and surface properties of Mnt change the surface and interface physical and chemical properties accordingly.The prepared new materials with different functional properties can be widely used in the field of environmental pollution repair as adsorbents,catalysts and coagulants for pollutants.This paper reviews the construction methods and progress of some major Mnt environmental mineral materials in recent years.We aim to discuss the effect of microstructure on adsorption performance,and to describe the structure-activity relationship between clay mineral structure and its adsorption performance with the hope of providing reference for the development of new and efficient environmentally friendly clay mineral environmental materials.