Signal Molecules To Improve The In Situ Regeneration Ability Of Zeolite Coating And The Continuous Remediation Of Sediment

Recently,it has been one of the hot issues for experts and scholars at home and abroad that how to control the pollution of sediments in rivers and lakes a nd solve the problem of eutropHication of water bodies.It is a more effective method to use in situ remediation and treatment of sediment pollution by using zeolite membrane technology.However,it is a difficult problem to remediate con tinuously.Therefore,this research compared NaCl modified zeolite and natural ze olite,and screened the denitrifying bacteria of high adhesion ability,WX15 HAT5.Then,adding signal molecule N-(3-oxohexanoyl)-L-homoserine lactone(OHH L)to biofilm bacteria in order to explore the effect of two zeolites with differen t surface behaviour on the adhesive ability of bacteria,the ability of in suit rege neration and remediate sediments continuously.This study determined the changes of Zeta potential and EPS of the biofilm attached to the zeolite under different conditions and explored the factors influencing bacteria attachment.Finally,the experiment was carried out to simulate the sediment cover in river environment.The purpose of this experiment is to explore the mechanism of in situ regenerati on in depth.The main conclusions are as follows:1.It can improve the in suit regeneration ability of biofilm zeolites effective ly to use denitrifying bacteria WX15 and HAT5 of of high adhesion ability to p repare biofilm zeolites.The in suit regeneration ability of biofilm zeolites is the highest under the condition of adding 2 ?M OHHL,which can effectively enhan ce the adhesion ability of bacteria.The efficiency of in suit regeneration under d ifferent amouts of ammonia adsorption(0.811mg/g,1.61 mg/g,2.02 mg/g,2.62mg/g,3.15 mg/g)was 88%,64%,51%,and 51% respectively.2.The zeta potential of bacteria surface was affected by the addition of sig nal molecules,which affected the adsorption capacity of bacteria on natural zeoli te.Moreover,the adsorption capacity of bacteria on natural zeolite was positively correlated with the fluorescence intensity,and the adsorption capacity increased with the increase of EPS fluorescence intensity.3.Adding signal molecule 2?M OHHL to the system containing Na Cl modi fied zeolite which change the surface properties of zeolite can significantly impro ve the adhesion ability of biofilm zeolite.4.The total nitrogen of sediment could be inhibited sustainably by the biofi lm zeolite cover which was modified by NaCl and added 2?M(the decreased a mount of ammonia was stable at 1.35~1.44 mg/g in two round sedimrnt remediat ion experiments)and the total nitrogen of overlying water was controled at 0.3m g/L~0.8mg/L.The water quality can reach surface water ?class water standard(TN<1.0 mg/L).