(140e) Impact of Shale and Clay Characteristics on Oil Removal from Industrial Wastewater

Recent research on water treatment has gained momentum in exploring the efficacy of clay minerals and biochars as adsorbents for treating industrial wastewater, particularly from the oil and gas industry. These materials present promising solutions for water purification challenges owing to their abundant availability, low cost, non-toxic nature, and favorable physiochemical properties. This project aims to undertake a comprehensive investigation divided into several phases. Initially, industrial wastewater undergoes thorough characterization, encompassing measurements such as oil and grease content, chemical oxygen demand (COD), total organic carbon (TOC), heavy metals, and hydrocarbon composition, to identify predominant contaminants. Subsequently, various local shale materials and clays featuring varied mineralogical compositions (e.g., silica rock, carbonate rock, bentonite) are screened for their potential as adsorbents to remove oil and organic compounds from wastewater. This phase involves in-depth characterization of the selected clay rocks using techniques such as Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), specific surface area analysis, contact angle measurement, and particle size distribution analysis. In the bench-scale adsorption experiments, the treated water underwent analysis for both TOC and oil content. A comparative study between selected clays is conducted to evaluate the impact of shale and clay characteristics on oil removal efficiency and identify functional groups contributing to superior adsorption performance. Further stages investigate the effects of various parameters such as clay concentration, contact time, particle size, temperature, and pH on removal efficiency. Optimal parameters are determined and treated water samples undergo comprehensive characterization. The most effective clay adsorbent is subjected to XRD and SEM analysis to illustrate the adsorption mechanism and visualize changes in surface area after treatment. Moreover, adsorption isotherm experiments are conducted to describe adsorbate-adsorbent interactions. Finally, desorption experiments are performed to investigate the potential for adsorbent regeneration. Initial analysis of industrial wastewater revealed oil and grease content of 496 mg/L and TOC of 7940 ± 39 mg/L. Preliminary results indicate that shale silica rock, characterized by 100% palygorskite and 58.8% SiO₂, exhibits a removal efficiency of 78.98%.