Insight into sulfapyridine degradation mechanism and antibacterial activity change using enhanced hydrolysis

Antibiotics in wastewater may inhibit the operation of biological treatment systems. Sulfapyridine (SPY) not only has antibacterial activity, but also chelates with other substances, and its antibacterial activity becomes stronger. An enhanced hydrolysis was applied to remove antibiotics as a promising pretreatment. An increase of 10 degrees C accelerated the SPY hydrolysis rate by 1.98-2.40 fold, and the hydrolysis half-life of SPY was shortened by 2.92 fold when pH was increased from 3 to 11 at 85 degrees C. Herein, the contribution of hydrolysis to the SPY degradation increased as temperature, and the cleavage of bond is mainly way of SPY hydrolysis. The trend in the TP1 concentration indicate that N-C cleavage may occur at the beginning of the reaction. According to result, the contribution of SPY to antibacterial activity decreased as the reaction progressed. The hydrolysis half-life of SPY was shortened by condition optimization under normal pressure. The optimal conditions are pH = 10.8 and 60 degrees C through response surface methodology (RSM) and EEO value with SPY concentration, antibacterial activity removal efficiency and low energy consumption as targets. Enhanced hydrolysis broken chemical bonds through hydrolysis and oxidation, shortening the hydrolysis half-life of SPY at high temperature and alkaline. The energy consumption of SPY hydrolysis was calculated for the first time. Under the conditions of pH = 11 and 65 degrees C, the energy consumption of per unit concentration SPY degradation was minimal. The results of this study demonstrated that enhanced hydrolysis is effective and energy conservation as a pretreatment technology for antibiotic.