摘要：从含重金属废渣堆积区土壤中筛选分离一种对重金属Pb2+、Cd2+具有高耐受性的功能菌株，用包埋法制备成固定化生物吸附剂，并将其用于吸附含重金属的废水。考察了重金属初始浓度、吸附时间、废水pH值、吸附剂投加量等影响因素对吸附性能的影响。实验结果表明：筛选出的菌株为短杆菌，对Pb2+、Cd2+的最大耐受浓度分别为2200 mg/L和700 mg/L；吸附剂投加量为10 g/L，废水pH为6时，Pb2+和Cd2+达到最大吸附率分别为87.77%和57.50%；Pb2+和Cd2+基本可在40min内被快速吸附而达到平衡浓度，最大吸附量分别达到114.36mg/g和82.12 mg/g；废水初始pH为5-7时利于吸附率的提高；Pb2+和Cd2+初始浓度的增加会使吸附率降低，且Pb2+比Cd2+的初始浓度对吸附速率影响更大。Langmuir和Freundlich方程吸附拟合表明，Pb2+、Cd2+的吸附主要为单分子层的表面吸附；Pseudo-second Orde动力学方程拟合说明，吸附过程的限速步骤主要为化学吸附，且Pb2+比Cd2+更容易被吸附。
Abstract: The functional strains with a high tolerance to heavy metals Pb2+ and Cd2+ was isolated from the soil of containing heavy metal waste accumulation zone, prepared by embedding immobilized bio-adsorbent and its application in adsorption of wastewater of containing heavy metals. The effects of initial concentration, adsorption time, pH value of wastewater, dosage of adsorbent on the adsorption performance were investigated. The experimental results show that the selected strains were brevibacteria, maximum tolerated concentration of Pb2+ and Cd2+ were 2200 mg/L and 700 mg/L; pH of the wastewater is 6, and the adsorbent dosage is 10 g/L, Pb2+ and Cd2+ reached the maximum adsorption rate are 87.77% and 57.50%; Pb2+ and Cd2+ basic can be rapidly adsorbed in the 40min and reached equilibrium concentration, and the saturated adsorption capacity reached 114.36 mg/g and 82.12 mg/g, respectively; the most suitable pH of initial wastewater for adsorption is 5-7; The increase of the initial concentration of Pb2+ and Cd2+ will decrease the adsorption rate, and the initial concentration of Pb2+ is greater than the initial concentration of Cd2+. Langmuir and Freundlich adsorption equation show that the surface adsorption of Pb2+ and Cd2+ in wastewater is mainly single molecular layer adsorption process; Kinetic equation fitting of Orde Pseudo-second shows that the rate limiting step of adsorption process is mainly chemical adsorption, and Pb2+ is more easily absorbed than Cd2+.
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