Study On The Preparation Of Al₂O₃/PVDF Supported Ni/Fe Catalytic Reductant And The Dechlorination Of Chloroacetic Acid

Chlorinated organic compounds are widely distributed, seriously harmful, difficultto be degraded and with high toxicity, so they have been named as priority control ofpollutants in many countries. Based on the study of zero-valent iron, supportednanoscale iron bi-metallic are used as catalytic reducing agent, with the advantages ofhigh activity, low cost and low pollution.In this paper, Al₂O₃·PVDF was used as thecarrier, Ni/Fe were immobilized. The preparation and characterization of catalyst,factors that affected dechlorination of chloroacetic acid were investigated.Impregnation method was used to prepare Ni/Fe/Al₂O₃·PVDF catalytic reductantbased on matrix modification of PVDF. Crosslinking liquid ratio and crosslinking time、dipping time in different nickel sulfate solution and nickel-iron ratio were investigated.Preparation technology were optimized by the dechlorination effect study ofmonochloro acetic acid （MCAA） and iron load of carrier.The method SEM was used to characterize Ni/Fe/Al₂O₃·PVDF catalytic reductant,observe surface morphology of the carrier prepared under optimized condition andanalyse the element composition qualitatively. SEM results indicated that Ni/Fe bimetalin the surface and cross-section of film carrier were uniformly distributed, whichpresented as spherical and lamellar structure without aggregation. EDS analysis furtherproved that Ni and Fe were covered on the surface of Al₂O₃·PVDF membraneMonochloro acetic acid（MCAA）was used as the target, dosage of reducing agent,initial pH, coexistence ions，the impact of water， reaction temperature, shaking speed,initial concentration, reducing agent storage time, these factors were studied to researchdegradation effect of MCAA. For trichloroacetic acid （TCAA）, initial concentrationwas studied to research the degradation effect, and the degradation process andmechanism were also analysed.Stored time and recycling times of carrier were examined, the results proved acertain stability of membrane carrier system. Carrier that stored in anhydrous ethanolfor30days could almost remain the same activity. Self-made nano Ni/Fe/Al₂O₃·PVDFmembrane in lab could be recycled for three times with good dechlorination effect.Initial concentration and dosage were examined to study on the dynamics ofMCAA and TCAA, the results showed that the reactions of MCAA and TCAA wereconsistent with first order reaction.