Catalytic Oxidation Of Difficult Degradable Industrial Wastewater By Heterogeneous Fenton-like Process

Dye wastewater and acrylic fiber wastewater were considered persistent industrialwastewater, it was difficult to obtain good results by biological method and othertraditional process.In order to achieve effective degradation of these two kinds ofwastewater, in this paper, the Fe-containing zeolite heterogeneous Fenton-like catalystswere prepared by impregnated evaporated method,and the treatment effect of these twokinds of wastewater by heterogeneous Fenton-like oxidation process were researched.The preparation of heterogeneous Fenton-like catalysts.The factors of impregnatingsolution concentration and calcination temperature were optimized by single factormethod with oxidation effect of analog Cationic Red X-GRL dye wastewater forevaluation indicator.The optimum preparation conditions were determined:impregnatingsolution concentration was0.18mol/L,calcination temperature was300°C. The catalystsprepared at these conditions had a higher iron content, better catalytic effect andstability. After repeated used three times,the catalysts still had a certain catalytic effectto degradate the dye wastewater,had the value of recycling.The analog Cationic Red X-GRL dye wastewater was oxidated by heterogeneousFenton-like process. In the experiment,the effect of reaction time, solution pH, catalystsdosage, H2O2concentration on treatment effect were investigated. And the optimumoperating conditions were determined:reaction time was120min,solution pH was3.0,catalysts dosage was20mg/L,H2O2concentration was30mmol/L.The removal rateof TOC，COD,TN of analog dye wastewater,respectively,were32.3%,23.9%,25.6%atthese conditions.The degradation effect was strengthened when Mn2+was added into theheterogeneous Fenton-like oxidation system, the best Mn2+concentration was15μmol/L.At the same time, the catalysts in the oxidation process had a certain adsorption capacityfor analog Cationic Red X-GRL dye wastewater, the adsorption effect was best at aboutpH=5.0,enhanced with the increase of the catalysts concentration.The biological effluent of acrylic wastewater was advanced treated by heterogene-ous Fenton-like oxidation and coagulation and sedimentation coupling method.And theoptimum operating conditions of the heterogeneous Fenton-like oxidation stage wasdetermined:solution pH was3.0,H2O2concentration was30mmol/L,catalysts concentr-ation was20.0g/L.At these conditions the removal rate of TOC,chroma,COD and TN reached60.3%,99.4%,55.5%,49.9%,respectively.In coagulation and sedimentationstage,firstly, the polymerization ferrous sulfate was the optimal coagulant for acrylicfiber wastewater,and the optimum coagulation parameters conditions were determined:wastewater pH was9.0,coagulant dosage concentration was300mg/L, flocculant PAMdosage was2.0mg/L,At these conditions,The removal rate of TOC,COD,TN ofwastewater,respectively,were19.3%,24.9%,10.0%by coagulation and sedimentation.The TOC,COD,TN removal rate of biological effluent of acrylic fiber wastewaterwere,respectively，60.8%,60.7%,52.1%,when treated by heterogeneous Fenton-likeoxidation coupled with coagulation and sedimentation method.The COD of effluentcould meet the wastewater discharge standards of chemical fiber industry.