CMC固定化灭活烟曲霉小球对活性艳蓝KN-R的吸附机理

Mechanism of biosorption of reactive brilliant blue KN-R by inactive Aspergillus fumigatus immobilized on CMC beads： Equilibrium, kinetics, diffusion and mass transfer

考察了羧甲基纤维素钠（CMC）固定化灭活烟曲霉小球吸附活性艳蓝KN-R的吸附平衡、吸附动力学和扩散传质过程．结果表明：CMC固定化灭活烟曲霉小球对活性艳蓝KN-R的吸附较易进行，吸附等温线能较好地用Langmuir模型和Freundlich模型来描述，而且用Langmuir模型更好，最大单分子层吸附量为66．7mg·g^-1．吸附动力学很好地符合准二级动力学模型．小球内部扩散过程用Weber-Morris模型拟合的结果反映小球内部扩散过程是其吸附控制步骤，且染料从小球液相边界层向小球表面的扩散过程亦不能忽略．用外部传质模型MathewsandWeber（M＆W）模型和FrusawaandSmith（F＆S）模型分别计算得到的外部传质速度的表征值β1S值均小于0．1h^-1,初始染料浓度越大，染料从液相到固相的外部传质速度越慢，而在小球内部越易扩散．

The equilibrium, kinetics, diffusion and mass transfer of biosorption of reactive brilliant blue KN-R by inactive Aspergillus fumigatus immobilized on sodium carboxyhnethylcellulose （CMC） beads were investigated. The biosorption proceeded easily. Both the Langmuir isotherm model and the Freundlich isotherm model could describe biosorption equilibrium well, but the Langmuir isotherm fit better than the Freundlich isotherm. The maximum monolayer biosorption capacity was 66.7 mg·g^-1. The biosorption kinetics data fit very well to a pseudo-second-order model. The biosorption data fit the intraparticle diffusion model via the Weber-Morris model, assuming that the intraparticle diffusion in the biosorption process is the ratecontrolling step, but the boundary layer diffusion of dye molecules should not be ignored. The external mass transfer coefficients/3~S values calculated by the Matthews and Weber （ M ＆ W） model and the Frusawa and Smith （ F ＆ S） model were less than 0.1 h^-1. The rate of external dye mass transfer from liquid phase to solid phase decreased but the intraparticle diffusion rate increased with increasing initial dye concentrations.