CTMAB-蒙脱石-细菌复合体对水中Pb~(2+)的吸附

研究了CTMAB-蒙脱石-恶臭假单胞菌复合体吸附Pb2+的物理化学特性,考察了时间Pb2+浓度、pH、温度对吸附的影响,结合FTIR探讨了其作用机理。结果表明,CTMAB-蒙脱石、细菌及其复合体对Pb2+的吸附是一个先快后慢的过程,90min时可基本达到平衡。Pb2+在细菌表面的吸附动力学以Elovich方程为最佳模型,其次为一级动力学方程。改性矿物-细菌复合体和CTMAB-蒙脱石对Pb2+的吸附均以一级动力学方程为最佳模型。Langmuir方程能很好地描述三种表面对Pb2+的吸附热力学。随着体系pH值和温度的升高,CTMAB-蒙脱石、细菌及其复合体对Pb2+的吸附率均逐渐升高。与CTMAB-蒙脱石相比较,EDTA对复合体表面Pb2+的解吸率较大,而去离子水和NH4Cl对Pb2+的解吸率较小。复合体与Pb2+之间可能存在络合、静电力和离子交换等作用力。

Adsorption of Pb2+ onto CTMAB-Montmorillonite-Pseudomonas putida Complex

Physico-chemical properties of Pb2+ adsorption onto CTMAB-montmorillonite-P.putida complex were investigated,as a function of time,Pb2+ concentration,pH and temperature.Mechanisms of adsorption were analyzed by Fourier Transform Infrared Spectroscopy(FTIR).Results indicated that adsorption of Pb2+ on surface of CTMAB-montmorillonite(CM),P.putida(P)or their complex(CMP)was a first fast and later slow process,and reached equilibrium within 90min.Sorption kinetics of Pb2+ onto P.putida could be described by Elovich equation very well,followed by first-order kinetics equation.The optimum model was the first-order kinetics equation for Pb2+ absorbed onto CM or CMP.Equilibrium adsorption of Pb2+ on the three surfaces could be fitted by Langmuir model quite well.The amount of Pb2+ adsorption increased with increasing of pH and temperature.Large difference existed between the percentage of Pb2+ desorbed with EDTA from bacteria-mineral complex and non-bacterial system.However,little discrepancies were observed for desorption of Pb2+ in corresponding system by NH4Cl and deionized water.Adhesion of Pb2+ onto surface of bacteria-mineral complex could be caused by complexing action,electrostatic force and ion exchange.