面向弱酸环境的硼吸附剂设计与制备基础研究

Adsorption process using an anion chelate resin is a promising technique for boron removal and recovery from aqueous solutions, however, the widely used N-methylglucamine-based chelate resin can only show better performace in the alkaline solutions with pH around 10. The fact that inferior performace of the chelate resin in acidic solution restricts its broad application in the field of chemical and enviromental industries. It is very necessary to develop a novel boron-selective sorbents for weak acidic solution. Organic-inorganic hybrid materials are of type of sorbents with their structures, compositions and properties adjustable. This project utilizes the discovery in salicylic acid's interaction with boric acid in acidic solutions to propose the present research on the preparation of hybrid boron-selective adsorbent. In order to prepare boron adsorbent with high-desity functional groups, we devise some novel silane monomers containing moiety of salicylic acid. The objective of this proposal is to explore the regulation method of controlled pore structure and properties of the adsorbents prepared by sol-gel reaction and to demonstrate the intrinsic relationship between the performance of the adsorbent and the density of salicylic acid as well as variation in the structure of salicylic acid derivatives. Thus it is possible for us to obtain a technique for preparing high-performenc boron adsorbents-based on the moiety of salicylic acid. If succeed, it is probable for the invented boron adsrobent to fill a gap in a practical application such as boron recovery from brine where we fail to use traditional N-methylglucamine-based chelate resin.

基于阴离子螯合树脂的吸附分离技术是从水相回收或脱除硼酸的有效方法，但现有基于N-甲基葡萄糖胺的螯合树脂在碱性条件（pH~10）才能发挥较好的吸附性能，酸性环境的硼吸附量普遍较低，制约了该类树脂在环保、化工等领域的广泛应用，迫切需要研发面向酸性环境的硼吸附剂。本项目拟利用有机-无机杂化材料具有结构、组成和性质可调的特点，针对水杨酸阴离子在弱酸溶液与硼酸中性分子发生螯合的特性，设计合成新型含水杨酸衍生物功能基的硅源单体，采用溶胶-凝胶法工艺并通过提高硅烷单体比例实现大容量硼吸附剂的制备，研究材料制备过程微观结构、组成与性能的演变规律，建立吸附剂水杨酸功能基结构-密度-吸附/传质/机械性能的内在联系，掌握高性能水杨酸功能基硼吸附剂可控制备关键参数。本项目可望发展一种新型硼吸附材料，弥补现有硼特效阴离子螯合树脂的不足，为盐湖卤水等弱酸环境中提硼应用奠定基础。

本项目针对传统聚合物型硼螯合树脂吸附功能基密度低、硼酸吸附容量普遍较低且易溶胀等问题，开展了硅基硼酸吸附分离材料制备研究。利用有机-无机杂化材料具有结构、组成和性质可调的特点，基于邻位双羟基功能基团与硼酸中性分子发生螯合的特性，设计合成新型含葡甲胺功能基的硅源前驱体，采用溶胶-凝胶化学原理并通过提高硅烷单体比例实现大容量硼酸吸附剂的制备。建立了反相悬浮聚合法可控制备球形有机-无机杂化吸附剂的工艺技术，系统研究了反相悬浮聚合工艺中分散剂种类及用量、分散介质种类及油水相比、分散质组分浓度、聚合反应时间、搅拌装置转速等因素对硼酸吸附剂的粒度、球形度、功能基密度的影响规律，获得了制备大容量硼酸吸附剂的优化工艺条件, 采用红外光谱、热重分析、比表面积分析、元素分析、X射线光电子能谱、X射线衍射等手段对吸附剂孔结构、功能基团密度、热稳定性等性能进行表征。所制备的毫米级球形杂化材料对硼酸的最大吸附容量达1.99 mmol/g，是目前商品化聚合物吸附树脂Amberlite-743（1.06 mmol/g）的两倍，且吸附性能受外来杂离子的影响小，该材料在盐湖卤水中吸附法提硼应用中表现出较好前景。在本项资助下，共发表SCI收录论文13篇、EI收录论文4篇，获得授权国家发明专利2项，完成人参加国内外学术会议12次，培养研究生4名和本科生1名。