Study On Removal Of Perfluorinated Compounds And Nanoparticles In Water By Modified Ceramsite

Perfluorinated compounds(PFCs)and nanomaterials are two types of new materials,that have been widly used in industrial and consuming products manufacturing due to their excellent physical and chemical properties.PFOS and PFOA are the trepresentative PFCs,and nano Ag and nano ZnO are the nanomaterials.Industrial wastewater discharge is the predominant source of the emission of these materials into the environments.Thus,appropriate wastewater treatment should be taken.Whereas,fouces are currently paid on the control and treatment of these materials in the manufacturing and wastewater trentment facilities within the plants.Few study addresses their removal from wastewater treatment effluent,contmniated rainwater,and discharge receiving river water.In this study,therefore,traditional ceramsite was modified and used as the filtring material for the removal of PFOS/PFOA,and nano Ag/nano ZnO in the above mentioned three scenarios.In this study,chitosan and ferric chloride were used as modifiers,the modification procedures were investicated,and the modified ceramiste were characterized.The chitosan modified ceramsites were used for PFOS/PFOA removal;and iron coated ones were used for nano A g/nano ZnO removal.In batch scale and dynamic column experiments,the removal efficacy of target pollutants was systematically investigated.The preparation method of chitosan modified ceramsite is: dissolving the chitosan powder in acetic acid solution(5%)and obtaining 1.5% chitosan acetic acid solution;in the following,adding prewashed ceramsites into the chitosan acetic acid solution with a mass to volume ratio of 2:1(g:m L);finally,after soaking for 24 h,the mixture was oven-dried at 55 ? prior to use.The preparation method of iron coated ceramsite is: adding 5 mol/L Na OH solution into 1 mol/L Fe Cl3 solution to reach pH 7 and obtain Fe(OH)3 suspension;then adding the prewashed ceramsite into Fe(OH)3 suspension with a mass to volume ratio of 4:1(g:m L);finally,the mixture was oven-dried at 110 ? prior to use.The theoretical maximum adsorption capacities of the chitosan modified ceramsite for PFOS and PFOA are 222.2 ?g/g and 158.7 ?g/g,respectively.The theoretical maximum adsorption capacities of iron coated modified ceramsite for nano-siliver and nano-zinc oxide is 232.6 ?g/g and 169.5 ?g/g,respectively.Chitosan modified and iron coated ceramsites can effectively remove the target pollutants in the pH range of 6 ~ 9.For the water with miscellaneous presence of the target pollutants and other conventional pollutants,the combination of these two modified ceramsites can achieve simultaneous removal of PFOS/PFOA,and nano Ag/nano ZnO.In the experiments simulating scenarios of the application scenario of simulating the rain mouth dirt separator,the simulating experiments of infiltration ditch and the simulating purification of river water by channel seepage zone,the modified ceramsites showed good removal efficiency for PFOS/PFOA,and nano Ag/nano ZnO.