Synthesis and characterization of activated carbon of Moringa oleifera Lam pod and evaluation of its performance in the removal of oils and greases

Abstract

Produced water treatment is crucial since its improper disposal can result in ecological damage. A widespread and effective technology for removing organic compounds in industrial effluents is adsorption. Approaches to treating real produced water using activated carbon with different activating agents lack discussions in the literature. The present study aimed to investigate the influence of acids, salts, and bases on the structure development of three activated carbon and their performance to remove oil and greases content (OGC) in produced water from an oil field. Moringa oleifera Lam was used as precursor material, and the influence of activating agents such as zinc chloride (ZnCl2), phosphoric acid (H3PO4), and sodium hydroxide (NaOH) was investigated. The adsorbents were characterized by elemental analysis (CHN), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and textural properties. The kinetic study showed that the pseudo-second-order kinetic model better represented the adsorbents. Among the activating agents, H3PO4 proved to be the most appropriate for producing an adsorbent with a large BET surface area, 1356.29 m2/g, and reaching an adsorption capacity equal to 294.41 mg/g. In addition, its chemical balance was described by Langmuir isotherm, suggesting chemical adsorption, while Freundlich isotherm adjusted well to experimental data of activated carbon with zinc chloride. Results indicated activated carbon with phosphoric acid or zinc chloride as alternative adsorbents for removal OGC since both had a percentage of oil and grease removal greater than 93%.