Preparation And Application For Carbon Nanotube Dynamic Membrane Based On Adsorption And Catalysis

Membrane technology plays an important role in purifying printing and dyeing wastewater.however,the problems like serious concentration polarization and membrane fouling,which reduce the membrane flux,are significant challenges faced by this technology.Therefore,necessary modification of the original membrane is often required.Carbon nanotubes?CNTs?,with excellent adsorption performance,good physical and chemical properties,is a kind of material widely used to absorb pollutants and also to modify membrane surface,while laccase,as a polyphenol oxidase,can effectively degrade various of dyes and micro-pollutants.Therefore,first,a carbon nanotube-adsorptive dynamic membrane?ADM?with nanofiltration performance is to prepared by carbon nanotubes and membrane,then,an improvement on the basic of ADM via adding laccase will be done,forming a novel biomimetic dynamic membrane?BDM?with biodegradable properties,so as to improve the efficiency of pollutant rejection and anti-fouling performance,as well as reduce membrane fouling and increase membrane flux.This work will be divided into two parts:ADM and BDM.In the first part,the effects of preparation time,CNTs loading amounts,transmembrane pressure?TMP?and shear stress on the preparation of ADM were investigated to evaluate its performance.The results showed that ADM with the best homogeneous porous structure on the surface could be prepared at the optimized condition(50 rpm,1 bar,55g m^-2 CNTs loading amounts and 10 min).Then,the impact of operation conditions?shear stress,TMP,CNTs loading amounts and dye types and concentration?on membrane flux and removal rate for ADM was studied.In addition,backwash cleaning can successfully adsorb saturated carbon nanotube layer on ADM at t 0.5 bar and 1min.In the second part,the effect of the two fabrication methods on the performance of the BDM is first investigated,and the results demonstrated that the mixed filtration way can ensure that laccase and CNTs were more completely combined.Furthermore,compared with that of ADM,the decontamination and stability for BDM with different operation conditions?CNTs and laccase loading amounts,dye concentration,agitation speed and TMP?were studied.The results showed that the CNTs and laccase loading amounts can reduce the filtration resistance and improve the catalytic properties.On the other hand,the backwash cleaning can more thoroughly remove the inactivated bionic layer and refabricate a new one.