摘要
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βIS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.
Batch studies and thermodynamics of biosorption of reactive brilliant KN-R by inactive Aspergillus fumigatus immobilized on sodium carboxymethylcellulose (CMC) beads were investigated. The results showed that the inactive Aspergillus fumigatus immobilized on CMC beads could effectively decolorize a solution containing 103.4 mg·L^-1 reactive brilliant blue KN-R by biosorption within the equilibrium time, viz. 48 h. The optimal initial pH of the dye solution was 10.5. The biosorption capacity increased with increasing temperature in the range of 10 - 50℃. In the beads dosage range of 1% - 5% ( wt % ), the biosorption efficiency increased from 54.2% to 94.9% , but the biosorption capacity decreased from 54.7 mg·g^-1 to 19.6 mg·g^-1 after 48 h equilibrium. High salinity in dye solutions had little influence on biosorption capacity. The biosorption capacity decreased only 5.6 mg·g^-1 at the NaC1 concentrations in the range of 0% - 3.0% (wt % ). The thermodynamics parameters values such as Gibb's free energy changes (△G) , enthalpy changes (△H) and entropy changes (△S) over the temperature range of 10 - 50℃ were: AG less than 0, △H 15. 343kJ. mol^-1 and AS 0. 0607 kJ·mol^-1·K^-1 . These values indicate that the biosorption process by inactive A. fumigatus immobilized on CMC beads was spontaneous and endothermic. The dye molecules movements increased slightly in randomness at the solid/liquid interface during the sorption of dye on the biosorbent.
出处
《环境科学学报》
CAS
CSCD
北大核心
2008年第1期83-88,共6页
Acta Scientiae Circumstantiae
基金
广州市环保局科技项目(穗计006)~~
关键词
固定化灭活小球
烟曲霉
活性染料
热力学
inactive immobilized bead
Aspergillus fumigatus
reactive dye
thermodynamics