Research On Degradation Of Methyl Orange By Sodium Persulfate Activated With Reduced Iron Powder And Activated Carbon

With the improvement of people's living standard,the demand for dyes in life and production is increasing.The azo dyes are the most widely used due to the large variety of species and the stability of azo dyes.The use of azo dyes occupies the whole dyestuff market more than half,followed by producing a large number of azo dyes wastewaterthe in the process of production and use of azo dyes.Azo two ends attached to the structure of the aromatic ring so that the molecular nature of azo dyes is very stable,and the intermediates of azo dyes aromatic amines are highly toxic and are carcinogenic,ogenic and mutagenic,which are highly harmful to organisms.Therefore,azo dyes become typical refractory wastewater.In this paper,we try to study the treatment of azo dyes wastewater by highly advanced oxidation method based on sulfate radicals in recent years,and we use methyl orange as a typical representative of azo dyes to simulate dye wastewater.Firstly,the optimum operating conditions and treatment effects of reducing iron powder and activated carbon activated sodium persulfate to degrade methyl orange wastewater were studied.Two kinds of improvement schemes were proposed for the problems in the study.Then the optimum conditions for the modification of activated carbon and the effect of modified activated carbon on the degradation of methyl orange were studied.Finally,the optimum preparation conditions for the preparation of composite catalyst with polyvinyl alcohol & sodium alginate& polyethylene glycol embedded reduced iron powder and activated carbon were studied,and the effects of the content of each component of the composite catalyst on the effect of the composite catalyst & sodium persulfate system on the treatment of methyl orange wastewater were studied.In the experimental stage of the treatment of methyl orange with reduced iron powder activated sodium sulfate,it was concluded that the acidic and neutral environment were more favorable for the degradation of methyl orange in the reduced iron powder / sodium persulfate system.The influence of the other four factors on the degradation of methyl orange by reducing iron powder & sodium persulfate system was as follows: reduction of iron powder dosage > reaction time > stirring rate >sodium persulfate dosage.The optimum treatment conditions were as follows: when the concentration of methyl orange solution was 200 mg/L,the dosage of reduced iron powder was 16 mmol/L(0.8936 g/L),the dosage of sodium persulfate was 1 mmol/L,stirring speed of 240 r/min,MO removal rate reached 73.15% after three hours of reaction.The experimental results show that the acidic,neutral and alkaline environments do not affect the degradation of methyl orange by the activated carbon & sodium persulfate system in the experimental stage of activated sodium activated sodium sulfate.The effect of the other three factors on the degradation effect of activated carbon & sodium persulfate system on the effect of methyl orange was as follows: the amount of activated carbon > reaction time > sodium persulfate dosage.The optimum treatment conditions were as follows: when the concentration of methyl orange solution was 200 mg/L,the dosage of activated carbon was 0.9 g/L,the dosage of sodium persulfate was 0.6 mmol/L and the speed was 240 r/min,and the removal rate of MO was 92.21% after 6h reaction.In the experimental stage of activated activated carbon activated sodium persulfate to deal with methyl orange,the results show that the influence degree of the three factors on the modification effect of modified activated carbon is:calcination temperature > FeCl3 solution concentration > calcination time.The optimum conditions for single factor optimization were: activated carbon was immersed in 0.4 mol/L FeCl3 solution and then calcined at 150 ? for 1 h.The effect of the activated carbon prepared under the optimum modification conditions was10.17% higher than that before modification.In the experimental phase of the composite catalyst activated sodium persulfate to deal with methyl orange,the results show that the higher the ratio of polyvinyl alcohol and polyethylene glycol in a certain range,the smaller the ratio of iron and carbon,the better the treatment effect of the composite catalyst & sodium persulfate system on methyl orange,and in a certain range,the optimum amount of sodium alginate was 0.4%.The effect of four factors on the degradation of methyl orange by composite catalyst / sodium persulfate system was: Fe/C ratio > SA content > PEG content > PVA content.The development of the composite catalyst has solved the problem of low utilization rate of sulfate radicals to a certain extent.