摘要
利用十六烷基三甲基溴化铵(CTMAB)对钠基膨润土(Bt)进行改性得有机改性膨润土(C-Bt),并与纳米TiO_(2)复合探究复合材料对目标污染物罗丹明B(RhB)的吸附-光催化降解耦合。采用X射线衍射、氮气低温吸附-脱附、扫描电子显微镜、傅里叶变换红外光谱、X光电子能谱等表征分析材料的理化性质和构-效关系。结果表明,改性显著增加了膨润土的层间间距和比表面积,从而促进了RhB的内、外传质。负载的TiO_(2)主要以锐钛矿相赋存,于C-Bt层间及外表面均匀分散,复合后有效增大了了TiO_(2)的比表面积,改善了材料的吸附性能。TiO_(2)/C-Bt对RhB的吸附去除率为48.34%,远高于未改性TiO_(2)的吸附效率(6.52%),通过理论计算证明了复合材料的外扩散速率与内扩散速率均得到了大幅提升。RhB的降解效率从55.49%(TiO_(2))显著提升至91.82%(TiO_(2)/C-Bt),表观一级动力学速率常数增加了两倍。复合催化剂光催化性能的提高主要归因于:(1)复合材料比表面积的增大和内外传质速率提升,有利于污染物的富集,增加了TiO_(2)与RhB的密切接触;(2)光催化过程产生的自由基能够降解C-Bt表面吸附的RhB分子,使材料的吸附性能得以再生,吸附-光催化二者的协同有利于RhB的高效去除。
Cetyltrimethylammonium bromide(CTMAB)was used to modify sodium bentonite(Bt)to obtain organic modified bentonite(C-Bt)with enlarged interlayer spacing.Ulteriorly,nano-TiO_(2) were inserted into C-Bt and the adsorption and photocatalytic activity of the composite materials for RhB were investigated.X-ray diffraction(XRD),nitrogen low temperature adsorption-desorption(BET),scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR)and X-ray photoelectron spectroscopy characterizations were used to analyze the physic-chemical properties and structure-function relations of the materials.The results show that interlayer spacing and specific surface area of Bt are improved after modification to strength internal and external mass transfer of RhB.The supported TiO_(2) is anatase and evenly inserted or distributed on C-Bt.The composite can effectively increase the specific surface area of TiO_(2) and improve the adsorption performance of the material.The adsorption removal efficiency of RhB by TiO_(2)/C-Bt reached to 48.34%,which is much higher than that of pristine TiO_(2)(6.52%).Theoretical calculation shows that the external diffusion rate and internal diffusion rate of the composite are greatly improved.The degradation efficiency of RhB increased significantly from 55.49%on TiO_(2) to 91.82%on TiO_(2)/C-Bt,and the apparent first-order kinetic constant increased by two times.The improvement of the photocatalytic performance of the composite catalyst is mainly attributed to:(1)The increase of the specific surface area of the composite material and internal-external mass transfer rate are conducive to the enrichment of pollutants,increasing the contact between TiO_(2) and organic pollutants;(2)The free radicals generated by the photocatalytic process can degrade the RhB molecules adsorbed on the surface of C-Bt,so that the adsorption performance of the material can be regenerated,and the synergy of adsorption and photocatalysis is conducive to the high efficiency of RhB remove.
作者
陈志力
张彦朋
Chen Zhili;Zhang Yanpeng(Center of Management and Service for Water Resources and Hydropower Engineering,Jiaxing 314001,Zhejiang,China;CCCC Shanghai dredging Co.,Ltd.,Shanghai 200120,China)
出处
《工业催化》
CAS
2021年第6期15-26,共12页
Industrial Catalysis
基金
国家自然科学基金(52070070)。
关键词
催化化学
二氧化钛
改性膨润土
吸附
光催化
协同去除
catalytic chemistry
titanium dioxide
modified bentonite
adsorption
photocatalysis
synergistic removal
