Environmental Chemodynamics Research Group, National Institute of Fundamental Studies, Kandy, 20000, Sri Lanka.
Ecosphere Resilience Research Centre, Faculty of Applied Sciences, University of Sri Jayewardenepura, Nugegoda, 10250, Sri Lanka.
Environ Res. 2021 Jun;197:111102. doi: 10.1016/j.envres.2021.111102. Epub 2021 Mar 30.
The present study investigated adsorptive removal of toluene and ethylbenzene from the aqueous media via using biochar derived from municipal solid waste (termed "MSW-BC") in a single and binary contaminant system at 25-45 °C. The adsorption was evaluated at different pH (3-10), experimental time (up to 24 h), and initial adsorbate concentrations (10-600 μg/L) in single and binary contaminant system. A fixed-bed column experiment was also conducted using MSW-BC (0.25%) and influent concentration of toluene and ethylbenzene (4 mg/L) at 2 mL/min of flow rate. The adsorption of toluene and ethylbenzene on the MSW-BC was mildly dependent on the pH, and the peak adsorption ability (44-47 μg/g) was recorded at a baseline pH of ~8 in mono and dual contaminant system. Langmuir and Hill are the models that match the isotherm results in a single contaminant environment for both toluene (R of 0.97 and 0.99, respectively) and ethylbenzene (R of 0.99 and 0.99, respectively) adsorption. In the binary system, the isotherm models matched in the order of Langmuir > Hill > Freundlich for toluene, whereas Hill > Freundlich > Langmuir for ethylbenzene. The adsorption in the batch experiment was likely to take place via cooperative and multilayer adsorption onto MSW-BC involving hydrophobic, π- π and n- π attractions, specific interaction such as hydrogen-π and cation-π interactions, and van der Waals interactions. The thermodynamic results indicate exothermic adsorption occurred by physical attractions between toluene and ethylbenzene, and MSW-BC. The breakthrough behavior of toluene and ethylbenzene was successfully described with Yoon-Nelson and Thomas models. The data demonstrate that the low-cost adsorbent derived from the municipal solid waste can be utilized to remove toluene and ethylbenzene in landfill leachate.
本研究通过在单组分和双组分污染物体系中，在 25-45°C 下，使用从城市固体废物中提取的生物炭（称为“MSW-BC”）来研究甲苯和乙苯从水溶液中的吸附去除。在单组分和双组分污染物体系中，在不同的 pH 值（3-10）、实验时间（长达 24 小时）和初始吸附质浓度（10-600μg/L）下对吸附作用进行了评估。还使用 MSW-BC（0.25%）和甲苯和乙苯的进水浓度（4mg/L）在 2mL/min 的流速下进行了固定床柱实验。甲苯和乙苯在 MSW-BC 上的吸附对 pH 值的依赖性较弱，在单组分和双组分污染物体系中，基线 pH 值约为 8 时，最大吸附能力（44-47μg/g）。Langmuir 和 Hill 模型分别对单污染物环境中的甲苯（R 分别为 0.97 和 0.99）和乙苯（R 分别为 0.99 和 0.99）吸附的等温线结果进行了匹配。在双组分体系中，对甲苯而言，等温线模型的匹配顺序为 Langmuir>Hill>Freundlich，而对于乙苯，其匹配顺序为 Hill>Freundlich>Langmuir。批次实验中的吸附可能通过甲苯和乙苯与 MSW-BC 之间的协同和多层吸附发生，涉及疏水、π-π 和 n-π 吸引、氢键-π 和阳离子-π 相互作用等特殊相互作用，以及范德华相互作用。热力学结果表明，甲苯和乙苯与 MSW-BC 之间的物理吸引导致了吸附的放热。甲苯和乙苯的穿透行为可以用 Yoon-Nelson 和 Thomas 模型成功描述。数据表明，从城市固体废物中提取的低成本吸附剂可用于去除垃圾渗滤液中的甲苯和乙苯。
