Brahma Bhanupriya, Das Megha, Sarkar Priyabrata, Sarkar Ujjaini
Department of Chemical Engineering, Jadavpur University, 188, Raja Subodh Chandra Mallick Road, Kolkata, 700032, West Bengal, India; Biosensor Laboratory, Department of Polymer Science and Technology, University of Calcutta, A.P.C. Road Kolkata, 700009, West Bengal, India; Department of Chemical Engineering, Bineswar Brahma Engineering College, Kokrajhar, 783370, Assam, India.
Department of Chemical Engineering, Jadavpur University, 188, Raja Subodh Chandra Mallick Road, Kolkata, 700032, West Bengal, India.
J Environ Manage. 2023 Jul 1;337:117764. doi: 10.1016/j.jenvman.2023.117764. Epub 2023 Mar 28.
P-Chloro-Meta-Xylenol (PCMX) is a widely used disinfectant. In the current pandemic scenario, its consumption has increased largely, and as a result, wastewater is loaded heavily with PCMX as a contaminant. Remediation of this ecologically toxic phenolic compound is therefore a burning issue. This study proposes an eco-friendly biosorption-based remediation technique to remove PCMX. A novel isolated phenol-resistant gram-negative bacterium, Pandoraea sp. strain BT102, is first encapsulated in biopolymeric calcium alginate beads. These beads are packed in a long adsorption tube and the contaminated water was passed through this packed tube resembling a plug flow reactor. This unique plug-flow set-up is capable of reducing PCMX concentration from 100 mg L to 2.85 μg L within 4 h using only 30 g of adsorbent, resulting in 99.99% removal efficiency. Adsorption isotherms and kinetics are studied using batch experimental data. A PCMX loading capacity of the encapsulated calcium alginate beads is found to be 961.7 mg g, and the Freundlich isotherm results suggested the phenomenon of cooperative adsorption. A good agreement of the pseudo-second-order kinetic model along with the intra-particle diffusion model suggests a multilayer diffusion-controlled adsorption process. Biosorption of PCMX by the bacterium-modified beads was confirmed by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), and Fourier-Transform Infrared spectroscopy (FT-IR) analyses. The application of multivariate model-based Response Surface Methodology (RSM) reveals flow rate to be the most important factor controlling the rate of bioremediation.
对氯间二甲苯酚（PCMX）是一种广泛使用的消毒剂。在当前的疫情形势下，其消费量大幅增加，结果废水中大量含有作为污染物的PCMX。因此，修复这种具有生态毒性的酚类化合物是一个亟待解决的问题。本研究提出了一种基于生物吸附的环保修复技术来去除PCMX。一种新分离出的耐酚革兰氏阴性细菌， Pandoraea sp.菌株BT102，首先被包封在生物聚合物海藻酸钙珠中。这些珠子被填充在一个长吸附管中，受污染的水通过这个填充管，类似于活塞流反应器。这种独特的活塞流装置能够仅使用30克吸附剂在4小时内将PCMX浓度从100毫克/升降至2.85微克/升，去除效率达到99.99%。利用批量实验数据研究了吸附等温线和动力学。发现包封的海藻酸钙珠对PCMX的负载量为961.7毫克/克，Freundlich等温线结果表明存在协同吸附现象。伪二级动力学模型与颗粒内扩散模型的良好吻合表明是一个多层扩散控制的吸附过程。通过透射电子显微镜（TEM）、扫描电子显微镜（SEM）、能量色散X射线（EDX）和傅里叶变换红外光谱（FT-IR）分析证实了细菌修饰的珠子对PCMX的生物吸附。基于多元模型的响应面方法（RSM）的应用表明流速是控制生物修复速率的最重要因素。
