硫化沉淀与粉末吸附剂耦合处理高浓度含Tl废水效能研究

The Efficiency of Combined Process of Sulfide Precipitation and Powdered Adsorbent for Highly Tl Contaminated Wastewater Treatment

对于高浓度含Tl废水,先采用硫化沉淀预处理,去除废水中大部分溶解态的Tl,然后通过投加吸附剂粉末的方法,深度去除废水中微量的Tl。通过硫化沉淀预处理试验,考察了Na_(2)S浓度、pH、盐度、共存重金属离子等因素对废水中高浓度Tl去除率影响。Na_(2)S沉淀对水中高浓度Tl的去除率高于FeCl_(3)混凝沉淀。在Na_(2)S投加量为80 mg/L、初始pH为13的条件下,Tl的去除率达98.51%,残余的Tl浓度仅为38.6μg/L,达到了预处理的目标。对于硫化沉淀预处理出水,巯基吸附剂对废水中低浓度的Tl的吸附去除效果优于粉末活性炭与钠基膨润土,处理出水中残余Tl浓度仅为2.4μg/L。硫化沉淀与粉末吸附剂耦合处理工艺对于高浓度含铊废水提标改造具有一定的参考借鉴作用。

For the treatment of wastewater containing high concentration of Tl,a great proportion of Tl was removed by sodium sulfide pretreatment,then the residual Tl was removed by the powdered adsorbent.The effect of sulfide precipitation operation parameters,such as sodium sulfide concentration,pH,total salinity,and coexisting heavy metal ions,on Tl removal efficiency was optimized through experiments.The results showed that the Tl removal efficiency of sulfide precipitation was higher than that of coagulation with ferric chloride under the same operating conditions.The Tl removal efficiency of 98.51%was obtained at a sodium sulfide concentration of 80 mg/L and initial pH of 13,and the corresponding residual Tl concentration was merely 38.6μg/L.The goal of the sodium sulfide pretreatment could be well achieved.Furthermore,the residual Tl in the supernatant of the sodium sulfide pretreatment could be successively treated by powdered adsorbent containing thiol groups,and the residual Tl concentration after adsorption was merely 2.4μg/L,which showed better performance than powdered activated carbon and sodium bentonite.The use of the combined process of sulfide precipitation and powdered adsorbent provides valuable information for the upgrading reconstruction of wastewater treatment plants.