固定化球形红假单胞菌处理电镀废水中Cd和Cr的研究

比较了4种固定化球形红假单胞菌(Rhodopseudomonas sphaeroides)处理含Cd、Cr重金属废水的效果,对固定化菌吸附Cd和Cr的工艺条件进行了优化,并通过生物反应器连续处理实际电镀废水,分析了处理后的效果。通过比较,确定了20g.kg-1沸石和20g.L-1海藻酸钠组合作为共固定材料,固定化菌对Cd和Cr的去除效果明显优于游离菌。采用正交试验优化废水处理工艺条件,结果表明,废水pH值、菌体投加量对固定化菌体的处理效果影响较大,当处理废水的pH值为6.0、菌体投加量为10.00g.L-1时,对40.00mg.L-1含Cd废水的去除率可达96.68%。4轮吸附-解吸循环试验结果显示,固定化菌体可重复利用3次,固定化菌体在使用第3次时,Cd去除率仍可达51.20%。在生物反应器中,用固定化菌体处理质量浓度为92.61mg.L-1的含Cd电镀废水,3h时对Cd的去除率达到98.80%,对含Cu、Au、Ni废水中重金属的去除率也高于90.00%。

Biosorption of Heavy Metals From Electroplating Wastewater by Immobilized Rhodopseudomonas sphaeroides.

Effect of immobilized Rhodopseudomonas sphaeroides treating cadmium (Cd) and chromium (Cr) containing wastewater was investigated and technological conditions for the immobilized bacteria to adsorb Cd and Cr ions were optimized in treating electroplanting wastewater continuously in a bioreactor. Results show that the bacteria immobilized in gel complex with 20 g ·kg~(-1) of zeolite and 20 g ·L~(-1) of sodium alginate were significantly better than free bacteria in removing Cd and Cr from the wastewater. Orthogonal experiments were conducted to optimize technological conditions for wastewater treatment. It was found that pH of the wastewater and inoculation rate of the bacteria were two major factors affecting heavy metals rermoving efficiency. When pH of the wastewater containing 40. 00 mg·L~(-1) Cd to be treated was 6. 0 and inoculation rate of the bacteria 10.00 g·L~(-1) , Cd removing rate reached 96.68%. Results of four cycles of sorption-desorption reveal that immobilized bacteria could last three cycles. Its Cd removing rate might still come up to 51.20% in the third cycle. In the bioreactor, immobilized R. sphaeroides was used to treat electroplating wastewater containing 92. 61 mg·L~(-1) Cd. Three hours of treatment removed 98.80% of the Cd in the wastewater and over 90. 00% of other heavy metals (Cu,Au and Ni) as well.