REMOVAL OF BTEX FROM REFINERY WASTE USING HDTMAC-MODIFIED OGWUTA SOURCE CLAY: ADSORPTION EQUILIBRIUM AND THERMODYNAMIC INCLINATIONS

Agha I.I; Ibezim-Ezeani M. U; Obi C

摘要

The possible non-compliance of refineries to the demands of environmenteal protection laws has led to the discharge of poorly treated and contaminated wastewater to the environment. Carcinogenic compoiunds such as benzene, toluene, ethylbenzene, and xylene (BTEX) find their way to the ecosystem. This study is aimed at investigating the isotherm and thermodynamics of the uptake of BTEX using hexadecytrimethylammonium chloride (HDTMAC)-modified natural Ogwuta clay. Batch adsorption process was used atdifferent BTEX concentrations and at temperatures of 303°K, 313°K and 323°K. Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and Tempkin models were used to describe the process while changes in enthropy (A5), enthalpy (AH), and Gibbs free energy (AG) of the process were evaluated. The maximum monolayer coverage capacity (qm) of 1.83,0.92, 0.86 and 0.69 mg/g of BTEX was lower than the calculated values of 4.94, 2.64, 2.76 and 2.20 mg/g respectively, implying uptake of pollutants through other mechanisms. The Dubinin-Radushkevich monolayer coverage range of 0.81-2.66 mg/g agreed with the monolayer coverage of the Langmuir model but with energy less than 1 kJ/mol. Freundlich adsorption intensities for BTEX were 1.64, 1.41, 1.11 and 1.22 respectivelyand R2 values of not less than 0.99 for each pollutant showed that the model best fits the process. Results of the thermodynamic parameters showed that the process was more feasible at increased temperature, endothermic and lead to increased randomnessat the solid-liquid interface. This study has presented hexadecyltrimethylammonium chloride-modified Ogwuta source clay as a veritable adsorbent for organic pollutant decontamination both from laboratory and real-life sources.

机译：不合规的炼油厂不遵守环境保护法的要求，导致对环境的处理不佳和污染的废水排除在外。苯，甲苯，乙烯和二甲苯（BTEX）等致癌综合会找到通往生态系统的方式。这项研究旨在研究使用六二铁甲基铵（HDTMAC）修饰的天然ogwuta粘土来研究BTEX摄取BTEX的等温线性和热力学。在303°K，313°K和323°K的温度下，使用了批次吸附过程。 Langmuir，Freundlich，Dubinin-Radushkevich（D-R）和Tempkin模型用于描述该过程，同时评估了该过程的Enthropy（A5），焓（AH）和Gibbs自由能（AG）的变化。最大单层覆盖能力（QM）为1.83,0.92、0.86和0.69 mg/g的BTEX低于4.94、2.64、2.76、2.76和2.20 mg/g的计算值，这意味着通过其他机制吸收了污染物。 DUBININ-RADUSHKEVICH单层覆盖范围为0.81-2.66 mg/g，与Langmuir模型的单层覆盖率一致，但能量小于1 kJ/mol。 BTEX的Freundlich吸附强度分别为1.64、1.41、1.11和1.22，每种污染物的R2值不少于0.99，表明该模型最适合该过程。热力学参数的结果表明，该过程在温度升高，吸热性并导致随机度增加的固液界面上更可行。这项研究介绍了六二烷基三甲基铵改性的Ogwuta源粘土，作为实验室和现实生活来源的有机污染物净化的名副其实的吸附剂。

REMOVAL OF BTEX FROM REFINERY WASTE USING HDTMAC-MODIFIED OGWUTA SOURCE CLAY: ADSORPTION EQUILIBRIUM AND THERMODYNAMIC INCLINATIONS

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