Ti/RuO2-IrO2电极电化学方法降解溶液中TBBPA及其降解机理探究

四溴双酚A(TBBPA)是世界上产量和用量最大的溴代阻燃剂之一,在河流、底泥及污水中持久存在,严重威胁环境和人体健康.探讨了阳极为Ti/RuO_2-IrO_2电极的电化学法对溶液中TBBPA的降解效率,并考察了电流密度(5~20 m A·cm~(-2))、初始pH值(3~11)、极板间距(1~3 cm)及电解质浓度(1~40 mmol·L~(-1))对降解速率的影响.研究结果表明,TBBPA的降解遵循一级动力学方程,在溶液初始浓度为5 mg·L~(-1)、电流密度为10 mA·cm~(-2)、电解质浓度为5 mmol·L~(-1)及极板间距为1 cm的条件下,60 min后TBBPA的降解率可达97.2%,且降解速率常数和半衰期分别为0.060 min~(-1)和11.6 min,能量消耗为105.3 k Wh·m~(-3).同时运用HPLC-MS/MS检测出中间产物双酚A(BPA)和2-溴苯酚,并推断其降解途径主要为在羟基自由基(·OH)作用下连续的脱溴过程中,苯环与异丙基之间的C—C键断裂生成BPA和2-溴苯酚.电化学法是一种高效的、有潜力的降解难降解有机污染物的方法,本文将为今后实际废污水中TBBPA的去除提供基础数据和技术参数.

Electrochemical degradation of tetrabromobisphenol A (TBBPA) in aqueous solutions by Ti/RuO2-IrO2 anode

Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants around the world. This study investigated the electrochemical degradation of TBBPA in aqueous solutions with Ti/RuO₂-IrO₂ anode. The effects of the current density (5~20 mA·cm^-2), initial pH (3~11), plate distance (1~3 cm) and electrolyte concentration (1~40 mmol·L^-1) on the electrochemical degradation of TBBPA were examined in a batch reactor. The results suggested that the degradation of TBBPA followed pseudo-first-order kinetics, and its degradation efficiency reached 97.2% after 60 min of electrolysis with an initial TBBPA concentration of 5 mg·L^-1 and 10 mA·cm^-2 current density in 5 mmol·L^-1 Na₂SO₄ electrolyte solution. Under these conditions, the degradation rate constant was 0.060 min^-1 and the degradation half-life was 11.6 min. The corresponding energy consumption was 105.3 kWh·m^-3. The intermediate products determined using electrospray (ESI) mass spectrometry were bisphenol A (BPA) and 2-bromophenol. The sequential debromination and C-C bond cleavage between one of the benzene rings and the isopropyl group due to the oxidation by ·OH radicals, were the possible pathways for the electrochemical degradation of TBBPA. The electrochemical degradation method could be a promising technique to reduce the toxicity of TBBPA and eliminate TBBPA from contaminated wastewater.