赤泥脱碱渣处理含铅废水

Treatment of Lead-containing Wastewater by Dealkalization Residue from Red Mud

采用微生物脱碱法对赤泥进行脱碱处理,并将脱碱后的中性赤泥残渣作为吸附剂处理含铅废水。从赤泥中选育的粟褐芽孢杆菌在合适条件下对赤泥的单次脱碱率达到30.2%,经过5级加菌处理后赤泥总脱碱率可达75.8%,脱碱渣pH稳定在6.68。并对脱碱后赤泥渣进行吸附重金属铅的试验。结果表明,在脱碱渣投加量1.0 g/L、吸附温度30℃、吸附质pH为6.5、吸附时间180 min的条件下,对100 mg/L的Pb(Ⅱ)溶液的吸附率约为80%。脱碱渣理论饱和吸附量为461.43 mg/g。赤泥微生物脱碱渣吸附Pb(Ⅱ)的过程符合准二级模型,化学吸附过程起主导作用,且是自发进行的。赤泥脱碱渣吸附Pb(Ⅱ)后,Pb(Ⅱ)主要以PbCO_(3)、Pb(OH)_(2)和Pb(Ⅱ)-Complex的形式存在。

The red mud was dealkalized by microbial dealkalisation,and the neutral red mud residue after dealkalization was used as an adsorbent to treat lead-containing wastewater.Under the suitable conditions,the single dealkalization rate of red mud reaches 30.2% with the breeded Bacillus fuscus miliaris from red mud,and the total dealkalization rate of red mud can reach 75.8% after 5-stage addition of bacteria,and the pH value of dealkalized residue is stable at 6.68.The experiment of adsorption of heavy metal lead by the dealkalizsed red mud residue was carried out.The results show that the adsorption rate of 100 mg L Pb(Ⅱ)solution is about 80% under the conditions including dosage of dealkalized slag of 1.0 g L,adsorption temperature of 30℃,pH value of adsorbent of 6.5,and adsorption time of 180 min.The theoretical saturated adsorption capacity of the dealkalized slag is 461.43 mg g.The adsorption of Pb(Ⅱ)by the microbial dealkalized slag of red mud conforms to the quasi-secondary model,the chemical adsorption process playes a dominant role,and the process is spontaneous.After adsorption of Pb(Ⅱ)from red mud dealkalization slag,Pb(Ⅱ)mainly exists in the form of PbCO_(3),Pb(OH)_(2) and Pb(Ⅱ)-Complex.