摘要
为高效去除废水中的苯酚,制备了十六烷基三甲基溴化铵(CTMAB)改性沸石(以下简称改性沸石),研究了改性沸石投加量、废水pH、反应时间等对废水中苯酚去除的影响,分析了改性沸石吸附废水中苯酚的动力学过程、等温线过程以及热力学特征,探讨了吸附作用机制。结果表明,CTMAB质量分数为1.2%时,改性沸石对苯酚的吸附量达到7.2mg/g,明显高于天然沸石(1.1mg/g);改性沸石投加量6g/L、反应时间40min、pH=10的条件下,废水中苯酚的去除率可达98.4%;二级动力学方程和Langmuir方程能更好地拟合改性沸石吸附废水中苯酚的过程,且吸附是自发、放热、熵增的过程。改性沸石吸附废水中苯酚的作用机制为:CTMAB中的R—N^+(R为基团)与天然沸石表面双电层中的H^+、K^+发生交换后,R—N^+与沸石表面结合,而CTMAB结构中的疏水基则向外(废水相),由此CTMAB在沸石表面形成了有机相,苯酚通过分配作用进入到沸石表面的CTMAB有机相中与R—N+缔合而得以去除。
Cetyltrimethylammonium bromide(CTMAB)-modified zeolite(hereinafter referred to as modified zeolite)was prepared and applied to improve phenol removal from wastewater.Effects of CAMAB-modified zeolite dosage,solution pH,and reaction time on phenol removal were investigated.Adsorption kinetics,isotherms,and thermodynamics were analyzed.Adsorption mechanisms during phenol removal were discussed.Results showed that the adsorption capacity of modified zeolite could reach 7.2 mg/g,higher than that of natural zeolite(1.1 mg/g)when the mass fraction of CTMAB was 1.2%.In the adsorption tests,when zeolite dosage was adjusted to 6 g/L,phenol removal rate reached 98.4%after 40 min reaction,with pH of 10.Further,pseudo-second-order model and Langmuir model provided the best fit for phenol adsorption process,which was spontaneous,exothermic and entropy-improved.For adsorption mechanism,R-N+(R was radical)in CTMAB was firstly exchanged with H+and K+in the double layer of natural zeolite,and then was binded to zeolite surface,while the hydrophobic group in CTMAB structure was outward(wastewater phase),and thus an organic phase was formed on the surface of the zeolite.The distribution of phenol in CTMAB organic phase and solution phase,the electrostatic adsorption between R-N+in modified zeolite surface and phenol molecular,were the two main adsorption mechanisms.
作者
王卓
郭俊元
张宇
张露
张国俊
WANG Zhuo;GUO Junyuan;ZHANG Yu;ZHANG Lu;ZHANG Guojun(College of Resources and Environment,Chengdu University of Information Technology,Chengdu Sichuan 610225)
出处
《环境污染与防治》
CAS
CSCD
北大核心
2018年第8期907-912,共6页
Environmental Pollution & Control
基金
四川省教育厅科研项目(No.16ZA0207)
成都信息工程大学中青年学术带头人科研人才基金资助项目(No.J201515)
关键词
苯酚
改性沸石
吸附动力学
吸附等温线
吸附热力学
吸附作用机制
phenol
modified zeolite
adsorption kinetics
adsorption isotherms
adsorption thermodynamics
adsorption mechanisms
