Catalytic degradation of m-cresol by coking sludge based biochar in chloride medium
A biochar was prepared from coking sludge and modified with nitric acid at low temperature.Afterwards,the degradation efficiency and mechanism of m-cresol in chloride medium was studied.Coking sludge(CSS)had a large specific surface area and was rich in functional groups,so its adsorption effect was strong.The adsorption removal rate of m-cresol with CSS was 27.1％.However,the adsorption effect of the coking sludge carbon through carbonization and modification was very weak,because the specific surface area and the number of functional groups were significantly reduced.In the catalytic degradation process,the removal rates of m-cresol and Total organic carbon(TOC)with the modified coking sludge carbon(CSSC-N)were 98.1％and 80.1％,respectively,which were much higher than those with the unmodified coking sludge carbon(CSSC-0).That was mainly because there were a variety of iron-containing substances in CSSC-N which was conducive to iron circulation,and the surface iron content was as high as 60.10％,providing catalytic active components.The removal rate of m-cresol and TOC was inhibited by Cl-,which was deceased with an increase of Cl-concentration.When the concentration of NaCl in wastewater was 5％wt,the removal rates of m-cresol during the catalytic repeat experiment were all above 70％.Therefore,CSSC-N with the chorine-resistant property had a high catalytic activity and stability in chlorine medium.Based on the results of three-dimensional fluorescence spectrometry analysis and intermediate products identification,the presence of Cl-affected the degradation process of m-cresol and chlorine-containing intermediates were produced.
catalytic wet peroxide oxidationcoking sludgebiocharm-cresolchloride medium
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