水滑石基苯酚选择性吸附材料的制备及再生研究

Preparation and Regeneration of Layered Double Hydroxide-Based Materials for Selective Phenol Adsorption

目前,水资源短缺和污染已经成为制约世界各国经济发展的重要因素。因此,工业废水治理及再生利用就成为各国研究的热点。其中,含酚废水是当今世界上危害大、污染范围广的工业废水之一,也是环境中水污染的重要来源。利用改性β-环糊精(CMCD)插层到水滑石(LDHs)层间制备出CMCD/LDHs复合材料实现其对废水中苯酚的选择性吸附,揭示了LDHs不同的金属元素组成、比例以及溶液pH值对苯酚及硝基苯吸附的影响规律,获得了对苯酚选择性吸附最优的Mg 2Al-CMCD LDH复合材料,并探讨了Mg 2Al-CMCD LDH对苯酚与硝基苯吸附的等温吸附过程、动力学过程和再生循环能力。结果表明Mg 2Al-CMCD LDH对苯酚具有显著的选择性吸附性能,当pH为6时,对苯酚的最大选择性吸附量为6.27 mg/g,而对干扰物硝基苯、苯胺及苯甲酸的吸附量分别为1.80、1.57、2.27 mg/g;吸附过程符合Freundlich等温吸附和二级吸附动力学;具有优异的循环再生能力,循环吸附5次后,吸附效率仍保持在85%以上。为废水中苯酚类物质选择性吸附材料的设计与制备提供了新的思路和途径。

At present,the shortage and pollution of water resources have become an important factor restricting the global economic development.Therefore,the treatment and recycling of industrial wastewater have aroused extensive research interests in various countries.Among them,phenol-containing wastewater is one of the most harmful and polluted industrial wastewater,it is also largely contributing the water pollution in the environment.In this work,CMCD/LDHs composites were prepared by intercalatingβ-cyclodextrin(CMCD)into layered double hydroxides(LDHs)and used for selective adsorption of phenol in wastewater.The effects of LDHs compositions and pH value of solution on the adsorption of phenol and nitrobenzene were evaluated.The optimal CMCD/Mg 2Al-LDH composite with the best selectivity for phenol adsorption was obtained.The isothermal adsorption process,kinetic process and regeneration cycle capability of CMCD/Mg 2Al-LDH for the adsorption of phenol and nitrobenzene were discussed.The results showed that CMCD/Mg 2Al-LDH had significant selective adsorption capacity for phenol.The maximum adsorption capacity for phenol is 6.27 mg/g at pH 6,while that for nitrobenzene,phenylamine and carboxybenzene are 1.80,1.57 and 2.27 mg/g,respectively.The adsorption process is in accordance with Freundlich isothermal adsorption and two-stage adsorption kinetics.It also has excellent recycling capacity that the adsorption efficiency still remains above 85%after five cycles.This study has provided a new idea and approach for the design and preparation of LDH-based materials for selective adsorption of phenol in wastewater.