Treatment Of Polyvinyl Alcohol Wastewater By Multivariate Microelectrolysis Coupled With Fenton Technology

Polyvinyl alcohol（PVA）wastewater is a typical organic wastewater with high concentration and hard to degrade because of its poor biodegradability,high COD concentration and complex composition.Micro-electrolysis coupled with Fenton technology not only overcomes the drawbacks of traditional Fenton technology with more iron sludge precipitation and high reagent dosage,but also features simple micro-electrolysis equipment,which is expected to be a new technology for efficient treatment of PVA wastewater.In this study,a micro-electrolysis coupled electro-Fenton reaction system was constructed with multivariate micro-electrolysis fillers to treat polyvinyl alcohol wastewater,the performance of the filler and optimal preparation conditions of the micro-electrolysis filler were evaluated by investigating the removal rates of PVA and COD from the wastewater.The microscopic morphology of micro-electrolytic fillers was characterized by XRD,XPS and infrared spectroscopy,and the macroscopic physical properties were analyzed by calculating the apparent density,bulk density,water absorption rate,wear rate and compressive strength of micro-electrolytic fillers.The multivariate micro-electrolysis coupled with Fenton technology was used to treat PVA wastewater,and the effect of each influencing factor on the treatment of PVA wastewater was investigated by single-factor experiments.Response surface experiments were designed based on the results of single-factor experiments to investigate the optimal reaction conditions.Characterization by UV-Vis,FT-IR,GC-MS and quenching experiments are carried out to investigate the degradation mechanism of polyvinyl alcohol.The results show that,The optimum conditions for the preparation of the pluralistic micro-electrolytic filler are:Cu addition of 3 wt.%,Fe/C of 2:1,bentonite addition of 25 wt.%,ammonium sulphate addition of 3 wt.%,calcination temperature of 900°C and calcination time of2.5h.The surface of the ternary filler prepared under this condition is loose and porous,which can provide enough active sites to degrade pollutants.Ternary fillers have good mechanical strength,large apparent density and bulk density,which means that the filled is easy to flush,replace and maintain,and difficult to plate.After response surface optimization,the optimal experimental conditions for the treatment of PVA wastewater by multivariate micro-electrolysis coupled with Fenton technology were that the initial p H of wastewater was 1.73,the coupling time of Fenton reaction was 46 min,the dosage of ternary filler was 15.17 g/L,and the dosage of H₂O₂ was 26.9 m L/L.Under these conditions,the removal rates of PVA and COD were 99.9%and 76.5%,respectively,indicating that the process has excellent treatment effect on PVA wastewater.In the process of investigating the degradation mechanism of PVA wastewater,it was found that the micro-electrolysis process dominated the removal of PVA,and the Fe²⁺and reduced H generated broke the chains of large molecules and decomposed them into small molecules.The effect of COD removal is more influenced by the Fenton process,copper ions have a catalytic effect on the subsequent Fenton reaction,and hydroxyl radicals can remove small molecules of organic matter generated by the micro-electrolysis reaction of PVA.The homemade micro-electrolysis fillers have good reusability and practicality.In this study,a multivariate micro-electrolysis coupled Fenton system was constructed using homemade micro-electrolysis fillers to treat PVA wastewater effectively,providing the theoretical basis and technical support for the industrial application of this micro-electrolytic coupled Fenton technology.