Assessment of Locally Sourced Illite/Kaolinite Clay as an Eco-Friendly Adsorbent for Remediation of Petroleum Hydrocarbon-Contaminated Groundwater

The present study aimed to comprehensively evaluate the efficacy of locally sourced Illite/Kaolinite clay as an eco-friendly adsorbent for remediating petroleum hydrocarbon-contaminated groundwater. The raw clay, obtained from the prestigious Algerian Society of Kaolin (SOALKA), underwent a meticulously controlled acid activation process using a 5M sulfuric acid solution at 95°C for a duration of 1 hour. To ascertain the improvement in sorption properties resulting from the activation process, a systematic characterization and evaluation of the clay were performed utilizing advanced analytical techniques, namely X-ray diffraction, the BET method, and Fourier transform infrared spectroscopy. The obtained characterization results provided compelling evidence of the presence of clayey minerals, specifically Illite and Kaolinite, alongside quartz, as well as a significantly porous structure, as clearly demonstrated by their commendable specific surface area of 20.4121 m2/g and 22.4981 m2/g subsequent to activation. Subsequently, batch laboratory-scale experiments were meticulously executed employing a precisely determined water-to-clay ratio of 1:1 to meticulously explore the adsorption behavior of the clay materials. The efficacy of the adsorbents was meticulously evaluated, with a particular focus on the abatement of chemical oxygen demand (COD), biological oxygen demand (BOD5), and critical hadrochemical parameters. Encouragingly, the comprehensive findings showcased remarkable COD removal efficiencies, attaining an impressive magnitude of 93.51% (raw clay) and a significantly enhanced 98.41% (activated clay) for oil-contaminated groundwater, and an equally noteworthy 92.6% (raw clay) and an astonishingly complete removal of 100% (activated clay) for gas-contaminated groundwater. Analogously, the BOD5 removal percentages exhibited considerable magnitudes, reaching 80% (raw clay) and 85% (activated clay) for oil-contaminated groundwater, and an even more impressive 94.7% (raw clay) and an exceedingly high removal of 99.7% (activated clay) for gas-contaminated groundwater. The compliance of the treated groundwater samples with the irrigation standards was established through the rigorous application of the Wilcox diagram, thus affirming their suitability for irrigation purposes. Given the achieved results, the local Illite/Kaolinite clay emerges as an exceptionally promising candidate for water decontamination endeavours. However, in order to comprehensively evaluate the process's economic feasibility and long-term sustainability, further research endeavours, particularly encompassing meticulous scale-up studies, are indispensable. The forthcoming comprehensive investigations will undoubtedly facilitate the seamless integration and practical implementation of this remarkable clay-based remediation strategy in real-world scenarios, thereby offering a tangible solution to the persistent challenges posed by petroleum hydrocarbon-contaminated groundwater.