Based On The Experimental Study Of Induction Heat Fixed Bed Dyeing Wastewater Treatment

Dye wastewater, with high colourity, organic content, complicated composition and instable water quality, is one of the refractory organic wastewater. In recent years, following the improvement of dyes in the anti-oxidation, anti-photolysis properties and resistance to biodegradation, the traditional biochemical cannot get a desirable result. Therefore, the promotion of advanced oxidation technology has significance in the removal of dye wastewater. Fenton oxidation and catalytic wet oxidation which are with high processing efficiency, quick response and low secondary pollution have been the emerging technology in the field of dye wastewater treatment.In the alternating magnetic field, magnetic materials would be heating sharply via hysteresis power loss and eddy current loss. The induction heat has been applied to the dye wastewater treatment. This kind of non-homogeneous reaction system requires ferromagnetic material with good induction properties or catalyst having a sensor kernel. Then the high frequency alternating magnetic around the fixed bed reactor (FBR) can produce heat which provide high energy for the material particles on the micro-surface selectively. Thus the high temperature effect of the micro-reaction area of solid/liquid is formed. The approach achieves the purpose of lower power consumption than the traditional way of heating in treatment of dye wastewater. In this research, sponge iron particles with strong magnetism were selected as the induction heat material. We changing the combined form of chemical elements of sponge iron, and by prepared for the catalyst with sponge iron wrapped and active metal loaded. The fixed bed reactor act on Violet D-BL dye wastewater via the induction heat, the micro-reaction area of high solid/liquid temperature was observed. The different influence factors of influent in FBR with sponge iron and CWPO treatment were investigated. The results showed that:(1) Combining the induction heating fixed bed reactor (IHFB) filled with sponge iron. the influence of different flow condition was researched. The experiment shows that the fixed bed filled with30.00g sponge iron of size20-40mesh can produce more induction heat in the same fixed bed volume. Different surface modification of sponge iron can lead to their slight difference of surface chemical composition and different outlet water temperature. The mean temperature in IHFB is Ni modified sponge iron. Co modified sponge iron and acid activated sponge iron from higher to lower. (2) The degradation rate of flow conditions in IHFB were investigated, and compared IHFB with traditional FBR by treating the direct D-BL wastewater. The results showed that IHFB is superiors to FBR which improved the decolorization rate by increase of wastewater temperature. While IHFB promotes the degrading of dye molecules via the micro-interface high temperature formed between sponge iron and aqueous phases. Better results were achieved by experiment direct violet, direct scarlet and acid black in IHFB. The degradation rate was increased by improving the temperature and decreasing the pH of flowing water. Low concentrations of Ni modified and high concentration of Co modified can enhanced the degradation to dye wastewater of sponge iron.(3) Choosing starch as carbon source, a nickel impregnated and C coated catalyst with magnetic core of sponge iron (mNiO/C) was prepared by calcination. After the treatment of static adsorption, the catalyst absorbs little dye substrate, which testified that dye molecules are mainly depredated via catalytic wet peroxide oxidation (CWPO) in the research of IHFB. In the study of induction heat CWPO, the flow conditions play roles in the degradation of dye wastewater. When the ration of iron and carbon is3:1, the catalyst support coated3times and calcinations for2hours under500℃can achieve carbon coated well. Choosing0.2mol/L Ni (NO3)2solution concentration maceration extract, we prepared a series of catalysts with different ration of the solid-to-liquid and various calcination temperatures.(4)The factors which affect the degradation of induction heat CWPO were investigated. The results indicate that the dosage of H2O2plays a main role in the removal of dye wastewater. The reason was that HO· radical decomposed from H2O2quickly at high temperature. HO-radical destroys the structure of the dye molecules, and the chain reaction among which oxidizes the dye molecules and achieved the wastewater degradation. The ratios of solid-to-liquid and H2O2dosage have a great effect on catalytic activity during the process of catalyst reaction. They affect the removal ratio of dye wastewater in induction heat CWPO. The experiment shows that mNiO/C has maximum degradation rate under the preparation conditions of1:1solid-liquid ratio (g/ml) and calcination temperature500℃in induction heating CWPO.