预处理青霉菌吸附中性红的研究

Adsorption of neutral red on biosorbents prepared from biomass of Penicillium sp.

以青霉菌(Penicillium sp.)为生物吸附剂,考察了预处理方法、初始pH、染料初始浓度、时间和温度对青霉菌体(以下简称菌体)吸附中性红能力的影响。结果表明,经NaHCO3预处理的菌体的吸附效果最好,当初始pH为5～6时,菌体吸附量达到最大,此时的菌体吸附量比未经处理的增大40%以上;中性红初始质量浓度为50～500mg/L时,菌体的吸附量随着染料初始浓度的升高而增大;NaHCO3预处理菌体吸附中性红的过程可用准二级动力学方程来表达;在25、30℃时,NaHCO3预处理菌体对中性红的吸附行为用Freundlich方程描述较好,而在35、40℃时用Langmuir方程描述较好;温度升高,饱和吸附量也随之增大。根据热力学函数关系计算出吸附焓变(ΔH)为53.54kJ/mol,表明该吸附反应为吸热反应,升高温度有利于吸附。25、30、35、40℃对应的吉布斯自由能变(ΔG)均小于0,表明菌体对中性红的吸附是自发过程。

The batch removal of neutral red from aqueous solutions by adsorption on biosorbents prepared from biomass of Penicillium sp. was investigated to determine the effects of pretreatment chemical and adsorption treatment conditions （pH, initial dye concentration, contact time and temperature） on the adsorptive capacity for the dye. NaHCO3 was the most effective chemical, among the 5 studied, for preparing the biosorbents; the NaHCO3 pretreatment increased the adsorptive capacity of the raw biosorbent by more than 40 %. The capacities, which increased with increasing initial dye concentration, were highest when the solution pH was 5-6. The dynamic adsorption capacity data were well described by the pseudo second order reaction rate model. The Freundlich isotherm model fitted the experimental data obtained at 25 ℃ and 30 ℃ better than the Langmuir isotherm model which was better for fitting the data of 35 ℃ and 40 ℃. The higher Langmuir maximum adsorption capacities （q0） found at a higher temperature was consistent with the positive △H （53.54 kJ/mol） for the endothermic adsorption process. The adsorption of neutral red on the biosorbents was spontaneous since △G was negative for all test runs.