低频超声／内电解法联用处理酸性红B废水

Degradation of azo-dye Acid Red B in aqueous solution by cast iron combined with low frequency ultrasound

为了探讨弱酸条件下低频超声/内电解法协同处理酸性红B(Acid Red B,ARB)的可行性,考察了弱酸条件下低频超声、内电解法及低频超声/内电解法联用对ARB模拟废水的处理效果。结果表明,使用低频超声单独处理时,ARB降解缓慢,经10min辐射后,ARB的去除率不足4.7%;内电解法降解ARB速率较慢,反应10min,ARB的去除率仅为49.9%;低频超声/内电解联合作用对降解ABR有明显的协同效应,反应10min,ARB的去除率达90.0%以上。反应过程符合一级动力学,在频率为59kHz,功率分别为175W和250W的超声波协同作用下,ARB降解的表观反应速率常数比单独内电解法分别提高了2.72倍和3.38倍。该工艺操作简便、快捷,具有广阔的应用前景。

The paper aims to present its authors＇ investigation over the degradation of azo-dye C. I, Acid Red B （ARB） by using cast iron in the absence and presence of low frequency ultrasound （59 kHz and 40 kHz）, The feasibility of the above said combination was explored by analyzing the concentration of modeling wastewater containing azo dye Acid Red B, For the purpose, we had assessed our study of the effects of pH and the power of ultrasound on the above mentioned degradation, The results of our investigation reveal that, the degradation rate of ARB was very slow by means of the single low frequency ultrasound in weak acid, whose removing rate was only 4,7% , after a 10 min reaction by low frequency ultrasound in weak acidic medium, while the removing rate of ARB can be 49.9% of ARB by cast iron after a 10 min reaction, it can then be made to rise over 90% by cast iron with low frequency ultrasound after 10 rain reaction. The combination of low frequency ultrasound and cast iron shows a remarkable synergistic effect on the degradation of ARB, which proves to follow the first-order kinetics model, On the other hand, while the first-order rate constant of ARB degradation by cast iron was only 7.50×10^-2 min^-1, the degradation by US-Cast iron proved to be 2.04×10^-1 min^-1 and 2,54 ×10^-1 min^-1 under 175 W, 59 kHz and 250 W, 59 kHz ultrasound irradiation, respectively. Furthermore, a 2.72-fold increase in the reaction rate can be observed in the presence of 175 W, 59 kHz ultrasonic irradiation as compared with that of absence of ultrasound. A 3.38-fold increase in the reaction rate was observed in the presence of 250 W, 59 kHz ultrasonic irradiation compared with that of absence of ultrasound. It was thus found that for azo-dye ARB, the rate of color decay was the first-order with respect to the visible absorption of the dye. The destruction of the naphthalene rings in azo dyes was slower than that of color. The process is easy to be operated, fast and feasible with a wide application foreground in the given engineering area.