Electrochemical Treatment And Resource Utilization Of Phenol Wastewater

In order to address the issue of resource utilization of phenol wastewater,the preparation of poly（phenol） film from phenol wastewater and itsmechanism was studied by electrochemical method. With a304stainless steelas working electrode, respectively with Na₂CO₃, Na₂SO₄,（NH4）2SO4as thesupporting electrolyte, simulated phenol wastewater was treated byelectrochemical polymerization, then phenol from the aqueous solution waspolymerized on stainless steel anode to be a yellow-brown film.Electrochemical polymerization behavior was studied by methods of dynamicpotential scanning, cyclic voltammetry and constant current in different pHelectrolyte, and shown that the electrode potential of polymerization reactionwould increase with pH decreasing. It was confirmed that the productscontained polyphenylene ether and the polymerization degree of productgenerated in the alkaline electrolyte was larger than in the acidic electrolyteby infrared analysis. Using scanning electron microscopy to analysis thephenol microstructure of poly（phenol）, it was observed that poly（phenol） filmhad many crack defects on its surface and the other parts of the film wassmooth and dense, besides, it was concluded that poly（phenol） film grewalong the sheet and there were a lot of cross-network structures among the layers to form a layered cross-connect structure.The scraping method, chemical reagents method, thermal decompositionmethod and electrochemical method was used to separateelectro-polymerization products from304stainless steel substrate, and foundthat the electrochemical method was the best separation way. Keeping currentdensity being above10mA/cm2on the interface between poly（phenol） and304stainless steel for3¹0minutes, there was a perfect separation betweenthem, besides, the stainless steel electrode can be directly reused. Morphologyof interface between products and matrix was changed by electrochemicalreaction to make the bonding force decreased, and ultimately the products andthe substrate was separated.According to the above experiment results, a new pattern that phenolwastewater was treated by the combination with electro-polymerization andelectro-stripping method was designed for resource utilization of phenolwastewater. Electrochemical parameters kept in polymerization condition,polymer film could be generated on the anode, and processing time is about10minutes, then the anode was taken out and placed in the the strippingsystem. The parameter was adjusted in stripping condition to remove thepolymers for3⁵minutes. In this condition, phenol content would be up to12mg/L and its removal efficiency was93.81%ten hours later. Besides, theproducts could be recycled. This approach effectively reduced the content ofphenol in wastewater, and got useful electro-polymerization products to reusethe phenol from wastewater. Applications of poly（phenol） were preliminarily studied. Corrosionresistance property, flame retardant property and chemical structure ofpoly（phenol） were tested, and it was concluded that poly（phenol） may be usedas anticorrosive coating, flame retardant and so on. Corrosion resistance ofthe films was characterized by electrochemical method. Poly（phenol） filmsformed in0.001⁰.1mol/L phenol solution can effectively improve corrosionresistance of stainless steel, and the film formed in0.1mol/L phenol and0.1mol/L Na2SO4mixed solution for an hour at room temperature, with2.4Vcell voltage, had the best ability in corrosion resistance.