Treatment Of Dyes Wastewater With Sodium Persulfate Advanced Oxidation Processes Intensified By A High Gravity Method

With the rapid economic development, the living standard of the Chinese people has improved significantly at the price of environmental pollution, which has become one of the urgent problems to solve. Dye wastewater is one of the major sources of water pollution. Azo dye is widely used in printing and dyeing industry and azo dye wastewater has received wide attention due to its large amount and strong toxicity to biology. Advanced oxidation processes (AOPs) are efficient treatment methods for dye wastewater, and persulfate AOPs exhibits bright application prospects because of high oxidation capability and good adaptability.The sodium persulfate advanced oxidation processes based on high-gravity technology to increase its oxidizing ability, including Na2S2O8/Fe2+, Na2S2O8/Fe2+/O3 and Na2S2O8/Fe2+/H2O2 processes. The influence of different working conditions for methyl orange decolourization were discussed and suitable decolorization conditions were determined, thus providing a new technology of dyes wastewater treatment. The main contents are as follows:(1)The Na2S2O8/Fe2+ process was used to degrade the methyl orange wastewater in the RPB. The effects of initial pH of solution, Fe2+ concentration, Na2S2O8 concentration, rotational speed of RPB, initial methyl orange concentration on decolorization were studied. The experimental results showed that the methyl orange decolorization rate increased with the increase of the Na2S2O8 concentration and rotational speed of RPB and decreased with the increase of the methyl orange concentration. The optimum conditions for decolorization were determined as Fe2+ concentration of 0.6 mmol/L and initial pH of 3to7.(2)The treatment of methyl orange wastewater in the RPB with the Na2S2O8/Fe2+/O3 process was studied and compared with the Fe2+/O3 process. The effects of initial pH of solution, reaction temperature, ozone concentration, rotational speed of RPB and gas/liquid ratio on methyl orange decolorization were studied. The experimental results indicated that the methyl orange decolorization rate increased with the increase of ozone concentration, rotational speed of RPB and gas/liquid ratio, and the optimum reaction temperature and pH for methyl orange decolorizaiton were 25℃ and 4 respectively.(3)The study used Na2S2O8/Fe2+/H2O2 processes in RPB to degrade methyl orange wastewater and compare with the Fe2+/H2O2 process, the operation conditions include initial pH of solution、reaction temperature、 H2O2 concentration、rotational speed of RPB and Fe2+ concentration were studied in these two processes. The experiment results showed the methyl orange decolourization rate was increased with the increase of H2O2 concentration and rotational speed of RPB, the optimum Fe2+ concentration was lmmol/L, and the best methyl orange decolourization rate at the initial pH of 4.