Removal of phenol from oilfield produced water using non-conventional adsorbent medium by an eco-friendly approach

Petroleum extraction generates substantial quantities of produced water, a challenge compounded by water scarcity in oil-producing regions, notably the Middle East. Leveraging produced water effectively, adhering to environmental standards, can offer a viable solution to the issue of water scarcity. This study explores the potential of mandarin peels as an available, cost-effective adsorbent for treating synthetic aqueous solution simulated to oil-field produced water, specifically targeting phenol, a dangerous pollutant. Employing a batch-mode adsorption unit, six operational factors—phenol concentration, acidity, agitation speed, contact time, adsorbent dose, and temperature—were investigated. Results revealed an inverse relationship between phenol removal and pH, concentration, and temperature, while direct correlations were observed with other variables. Mandarin peels exhibited notable phenol recovery, reaching a maximum efficiency of 74.43% at pH 1, 450 rpm agitation speed, 38 ppm initial concentration, 5 g dose, time of 180 minutes, and 20°C temperature. Isothermal and kinetic analyses favored the Langmuir and intra-particle diffusion models. Thermodynamically, the process proved exothermic, marked by low entropy, and spontaneous within the tested temperature range. Adhering to the zero residues level concept, exploring beneficial and safe disposal methods for contaminated residues led to investigating toxic mandarin peel residue as a rodenticide, displaying promising efficacy on laboratory albino rats. Consequently, this study proposes a sustainable approach, treating produced water laden with toxic pollutants using readily available agricultural waste while concurrently repurposing the toxic waste into an environmentally friendly material, aligning with the zero waste level concept.