摘要
从皮革铬鞣、复鞣污泥等处分离、纯化出4株菌株TP、XB、MY和TQ,采用海藻酸钠悬滴法并添加膨润土制成微生物固定化吸附剂,研究该吸附剂对低质量浓度Cr3+的吸附特性。结果表明,4种固定化颗粒对低质量浓度Cr3+有较好的吸附作用。实验室条件下,当吸附温度为30℃时,6 h后固定化吸附剂进入缓慢吸附和平衡吸附阶段。吸附等温曲线拟合研究表明,不同温度下吸附剂适合不同的等温模型。4种微生物吸附剂均与Lagrange拟二级动力学模型拟合最佳,且吸附量从高到低为TQ、TP、XB、MY。颗粒内扩散模型研究表明,20℃下XB和MY对Cr3+的吸附分为快速吸附和缓慢吸附阶段;30℃和40℃下固定化颗粒均呈现表面吸附—缓慢吸附—平衡吸附过程。热力学研究表明,吸附反应均属于自发进行的吸热过程,并且均是化学吸附。
This article is aimed to reduce the low concentrated Cr3 ＋ in the environment by using new composite immobilized microorgan- ism adsorbents, that are, the 4 kinds of microorganism adsorbents （TP, XB, MY and TQ） isolated from the chrome-tanned leather building section and the activated sludge from the sewage. In this ar- ticle, we have adopted the sodium alginate pendant-drop method to produce the immobilized microorganism adsorbents added by bentonite in hoping to improve the adsorption efficiency. The results of our ex- periment and analysis show that the 4 immobilized microorganism ad- sorbents turn to be effective to adsorb the low concentrated Cr3 ＋ in the l!quid phase. In laboratory conditions, the said results indicate that at 30 % the adsorption of Cr3 ＋ by immobilized microorganism adsorbents has entered into the slow adsorption and equilibrium ad- sorption phases during the 6 h period and the mass concentration of Cr3＋ in the residual solution after TP, XB, MY, TQ adsorbing turned to drop from 5 mg/L to 0.47 mg/L, 1.19 mg/L, 1.54 mg/L and 0.23 mg/L, respectively. In the process, the adsorption rate of all the immobilized microorganism adsorbents may have been over 70% . In our experiments, we have used 2 adsorption isotherm mod- els （Langmuir and Freundlich isotherm models） to fit the experimen- tal data. As a result, different kinds of adsorbents should be made suitable h）r the different models at the temperatures of 20 - 40 ℃ , thus showing it was easy to proceed with the adsorption process of Cr3＋ by immobilized adsorbent particles. Besides, the kinetic study results were found in much better agreement with Lagrange pseudo- second-order model than with Lagrange pseudo-first-order model with the order of adsorption quantity being TQ 〉 TP 〉 XB 〉 MY based on the calculation results. What is more, the fitting of intraparticle diffu- sion model proves that the adsorption process of Cr3 ＋ by XB and MY had been going on in 2 steps （fast and slow adsorption phases） in 20 ℃
出处
《安全与环境学报》
CAS
CSCD
北大核心
2015年第2期178-183,共6页
Journal of Safety and Environment
关键词
环境科学技术基础学科
固定化
等温吸附模型
动力学
热力学
basic disciplines of environmental science and technolo-gy
immobilization
isothermal adsorption model
kinet-ics
thermodynamics
