丝瓜络固定化非活性颤藻对Pb2+的吸附特性

Biosorption characteristics of non-living Oscillatoria lutea immobilized in loofa sponge for removal of Pb2+

为研究丝瓜络固定化非活性颤藻对Pb2+的吸附特性,选择游离颤藻为对照,考察环境因素对吸附过程的影响以及吸附动力学、等温线和吸附机理.结果表明,固定化和游离颤藻分别在90 min和60 min达到吸附平衡,与对照相比,吸附量增加了约20.6%;随着Pb2+浓度的增加,固定化和游离颤藻的吸附量逐渐增加,并在70 mg·L-1和60 mg·L-1时,分别达到吸附饱和;吸附量依赖于pH的变化,当pH5时吸附量达到最大;吸附过程符合准二级动力学模型;Langmuir等温方程很好地描述了固定化和游离颤藻对Pb2+的吸附过程,属于单分子层吸附,饱和吸附量分别为87.82±1.51 mg·g-1和70.87±1.86 mg·g-1;傅里叶红外光谱(FTIR)和X射线能量色散光谱(EDS)分析表明,氨基、羧基、羰基和羟基与Pb2+的络合作用是固定化和游离颤藻的主要吸附机理.

To investigate the biosorption characteristics of loofa sponge-immobilized biomass of non-living Oscillatoria lutea for removal of Pb2+,the effects of environmental factors on biosorption,kinetics,isotherms and biosorption mechanisms were studied and the free biomass of O.lutea were used as the control group.The results presented that the Pb2+biosorption equilibrium of immobilized and free O.lutea were established in 90 min and 60 min,respectively,and compared with the latter,the biosorption capacity of the former increased by some 20.6%.The Pb2+biosorption amount increased as the initial concentration of Pb2+increased.And saturation Pb2+concentration of immobilized and free O.lutea were 70 mg·L-1 and 60 mg·L-1 respectively.The biosorption amount was pH-dependent,being maximum when pH was 5.The pseudo second order model was found to correlate well with the biosorption process.The biosorption of Pb2+was well described by Langmuir adsorption isotherms,belonging to monolayer sorption.Meanwhile,maximum biosorption capacity of immobilized and free O.lutea were 87.82±1.51 mg·g-1and 70.87±1.86 mg·g-1 respectively.The analysis results of FTIR and EDS revealed that the biosorption mechanism immobilized and free O.lutea mainly were the complexation between amino,carboxyl,carbonyl and hydroxyl groups and Pb2+.