Study on Treatment of Methyl Orange Printing/Dyeing Wastewater by Advnaced UV/Acetylacetone System

FENG Qirui; TANG Yuchao; WANG Kun; WU Changnian; HUANG Xianhuai; ZHANG Xinyu; ZHU Xiansheng; CHEN Caihong; LIU Jun

doi:10.19672/j.cnki.1003-6504.1648.23.338

Abstract：The bench-scale experimental study intends to explore the degradation mechanism of methyl orange(MO)using an advanced oxidation system which combines UV with acetylacetone(AA).As a result,the experimental study presented that the UV/AA system was much better than the UV/H2O2 system with respect to the effectiveness of decolorizing MO,as the ini-tial concentration of MO in the wastewater was 15 mg/L and the dosage of AA was 0.5 mmol/L,the degradation rate of MO could be as high as 98.4%after photolysis of 12 min,and in the UV/AA system the degradation of MO was in compli-ance with the zero-order-kinetic model(R2>0.990)regardless the initial mass concentration.When the value of pH was ap-proximately 2.0,the degradation rate of MO in 6 min.could reach up to 99.3%,an increase of 58.1%higher than that the pH of 9.0 or so.On the other hand,the inorganic anion HCO3-had a significantly inhibitory effect on the system,low concentra-tion of Cl-slightly promoted it,while high concentrations,and SO42-made almost no effects on the degradation rate,and the printing/dyeing auxiliary sodium citrate also exerted notable adverse effect on the degradation of MO.Furthermore,the results of free-radical-capture experiment and the electron paramagnetic resonance(EPR)test indicated that the most of the active-oxides in the UV/AA system was 1O2.The result of treating printing/dyeing wastewater in terms of TOC indicated that this UV/AA advanced system had a certain degree of mineralization ability;UV-Vis absorption spectroscopy analysis showed that the azo bond was basically broken down in 12 min;and AA concentration decreased as the reaction being in progression.According to the results of analysis using LC-MS,it was speculated the conversion pathway of MO in the degradation process of UV/AA advanced oxidation system.