本研究采用硫化氢为除砷药剂,向强酸性废液中通入硫化氢气体,实现砷在强酸性条件下直接去除.实验优化了反应压力、反应温度、硫酸浓度等反应条件,对沉淀絮体以及反应沉渣进行了表征,研究结果表明,在反应压力为0.22 MPa、反应温度低于55℃条件下,硫酸浓度在2%—20%范围内的含砷废液均可达良好除砷效果,废液中砷浓度可由500 mg·L~(-1)降到0.5 mg·L~(-1);废液酸度升高有利于形成密实絮体颗粒;反应产物主要为硫化砷.
In this work,H_2S was employed for arsenic removal from highly acidic wastewater with arsenic. In this process,arsenic can be removed directly under highly acidic condition. Influencing factors of the reaction such as pressure,temperature and H_2SO_4 concentration in the wastewater were optimized and the floc and sludge were characterized. Results showed that,for acidic wastewater with H_2SO_4 concentration of 2%—20%,the highest arsenic removal efficiency was achieved under pressure of 0. 22 MPa and temperature of below 55 ℃. In that case,arsenic concentration in the wastewater decreased from 500 mg·L~(-1) to 0.5 mg·L~(-1). Besides,increase in H_2SO_4 concentration of the wastewater benefitced the formation of dense floc particles. The main reaction product was indentified to be As_2S_5.