Kinetic Viewpoint of BTEX Removal Using Ehugbo-Nigerian Kaolinite Clay Modified with Hexadecyltrimethylammonium Chloride (HDTMAC)

Aim: Refinery wastes have been regarded as a consortium of majorly organic pollutants and improper management metamorphose to the distortion of human and environmental domains. In this study, the efficiency of hexadecyltrimethylammonium chloride (HDTMAC)-modified Ogwuta kaolinite clay in the removal of benzene, toluene, ethyl benzene and xylene (BTEX) from refinery wastewater was evaluated.

Methodology: Batch adsorption process was employed in the evaluation. The initial and final concentrations determined using Gas Chromatography-Mass Spectrometer (GC-MS) at different time intervals of 10, 20, 30, 40 and 60 min. Pseudo-first order, pseudo-second order, and intra-particle diffusion kinetic models were employed to analyze experimental data generated.

Results: Results showed that 92.0, 80.0, 75.3 and 78.7% removal efficiencies of benzene, toluene, ethyl benzene, and xylene were achieved within 20 min. The result further revealed that pseudo-second order kinetic model fitted best with R-squared values of 0.999 for each of the hydrocarbon pollutants. The calculated equilibrium capacity of 5.00, 2.722, 3.14 and 2.31 mg/g were approximately equal to that generated experimentally. This study reveals that pseudo-second order rate constant was nearly proportional to the size and structure of the monocyclic hydrocarbon pollutants with removal efficiency in the order of benzene = toluene ˃ xylene ˃ ethyl benzene.

Conclusion: This study has revealed that modified kaolinite clay can serve as a veritable option for the removal of BTEX and other organic pollutants from both wastewaters and other sources.

Future Scope of Study: This study recommends that further work on adsorption and desorption with respect to other inorganic and organic pollutants should be carried out using the product and hence, the findings obtained will form a blue-print in environmental regulation formulations and policies.