S Melvin Samuel, M Evy Alice Abigail, Chidambaram Ramalingam
School of Bioscience and Technology, VIT University, Vellore, Tamil Nadu, India.
PLoS One. 2015 Mar 18;10(3):e0116884. doi: 10.1371/journal.pone.0116884. eCollection 2015.
Biosorption is a promising alternative method to replace the existing conventional technique for Cr(VI) removal from the industrial effluent. In the present experimental design, the removal of Cr(VI) from the aqueous solution was studied by Aspergillus niger MSR4 under different environmental conditions in the batch systems. The optimum conditions of biosorption were determined by investigating pH (2.0) and temperature (27°C). The effects of parameters such as biomass dosage (g/L), initial Cr(VI) concentration (mg/L) and contact time (min) on Cr(VI) biosorption were analyzed using a three parameter Box-Behnken design (BBD). The experimental data well fitted to the Langmuir isotherm, in comparison to the other isotherm models tested. The results of the D-R isotherm model suggested that a chemical ion-exchange mechanism was involved in the biosorption process. The biosorption process followed the pseudo-second-order kinetic model, which indicates that the rate limiting step is chemisorption process. Fourier transform infrared (FT-IR) spectroscopic studies revealed the possible involvement of functional groups, such as hydroxyl, carboxyl, amino and carbonyl group in the biosorption process. The thermodynamic parameters for Cr(VI) biosorption were also calculated, and the negative ∆Gº values indicated the spontaneous nature of biosorption process.
生物吸附是一种很有前景的替代方法，可取代现有的从工业废水中去除六价铬的传统技术。在本实验设计中，研究了黑曲霉MSR4在间歇系统中不同环境条件下从水溶液中去除六价铬的情况。通过研究pH值（2.0）和温度（27°C）确定了生物吸附的最佳条件。使用三参数Box-Behnken设计（BBD）分析了生物量剂量（g/L）、初始六价铬浓度（mg/L）和接触时间（min）等参数对六价铬生物吸附的影响。与测试的其他等温线模型相比，实验数据很好地拟合了朗缪尔等温线。D-R等温线模型的结果表明生物吸附过程涉及化学离子交换机制。生物吸附过程遵循准二级动力学模型，这表明限速步骤是化学吸附过程。傅里叶变换红外（FT-IR）光谱研究揭示了羟基、羧基、氨基和羰基等官能团可能参与了生物吸附过程。还计算了六价铬生物吸附的热力学参数，负的∆Gº值表明生物吸附过程的自发性。
