Study On The Treatment Of Dyes Aqueous Solution By The Combination Of Electrocoagulation And Photocatalysis

Electrocoagulation and photocatalysis, each of which has own characteristic for organic wastewater treatment, are extensively used in wastewater treatment respectively. By electrocoagulation the tiny solids and colloids can be coagulated; electrolytes are decomposed; organics are adsorbed and floated, then oxidized or deoxidized. By electrocoagulation the suspended solids and colloids can be removed, as well as silicon ions, iron ions, manganese ions etc. In addition to these, it can be used for disinfection, decolonization, fluorin removal and water demineralization. During the course of electrocoagulation the organics should be degraded effectively by hydroxy free radical (-OH), ozone etc. created from anode reaction. The approach makes organics degraded more thoroughly, with little toxic intermedia product, which accord with environmental conservation. It is not apparent to remove organic wastes by photocatalysis, however, which might destroy some organic dye molecular diazonium color base, making chroma of polluted water decrease greatly and converting organic high molecule to tiny organic molecule which is helpful to following biochemical polishing treatment.Both of the two processes are used to primary treatment of organic wastewater, but so far there have never been reports about the combination of them used for wastewater treatment. The complex process, namely the combination of electrocoagulation and photocatalysis has extensive developing space and wonderful prospect in the field of water purification.Representative stuff-RBBRX-3B selected are degraded by the combination of electrocoagulation and photocatalysis in this paper. The feasibility, validity of the technology is probed. This is the technical innovation in the field of water treatment, and this is also the most important section of the thesis.The relevant parameters that influence treatment efficiency of electrocoagulation and photocatalysis in the experiment are studied separately. The results show that stuff-RBBRX-3B water is discolored perfectly when the two processes are used to treat the water respectively. Comparing the two results experimentally: electrocoagulation is effective to high concentration dyes aqueous solution, both the efficiency removal of chroma and that of organic matter can get 70%~95%; photocatalysis is suitable for low concentration dyes aqueous solution. When low density stuff-RBBRX-3B water is treated by photocatalysis, suspending catalyst are used in the experiment. Under the proper intensity and dosage of light, the effect of chroma removal is remarkable.It is time-consuming to treat stuff-RBBRX-3B water only by electrocoagulation; it is desired for photocatalysis that the initial density is not too high which bring about high chroma retarding permeation of ultraviolet radiation; therefore the interest of the combining treatmentprocess is that the water is treated first by electrocoagulation, then by photocatalysis.It is feasible and effective for high concentration stuff-RBBRX-3B with the electrocoagulation and photocatalysis combined treatment process. The association of two techniques might make up for each other, increasing overall treatment efficiency of stuff-RBBRX-3B water. First high concentration dyes aqueous solution is cleansed by electrocoagulation, becoming clear with all kinds of wastes reduced, which is favorable to improve the result of the following photocatalysis treatment and further elevate the colority removal and the CODcr removal of stuff-RBBRX-3B water.