Adsorptive removal of emulsified crude oil from produced water using modified biowaste; its kinetics and thermodynamic study

Abstract The recycling and reuse of a naturally occurring biowaste (Cuttlefish-bone, CB) for the active removal of organic moieties originating from crude oil contaminants from low-saline-produced water is investigated in this study. Cuttlefish bone powder, primarily composed of calcium carbonate, was prepared, characterized, and modified for use in the tertiary treatment of emulsified oil/water mixtures with low oil content (around 100 ppm). The aim was to assess its potential as an adsorbent material for removing residual oil from water during the final stage of wastewater treatment. Alkaline treatment was done to improve the surface charge and porosity of the adsorbent. The surface area and the surface volume of the treated CB increased from 3.4 m 2 /g to 11.8 m 2 /g and 6.8 nm to 15.1 nm respectively. Batch adsorption analysis of the adsorbents for the adsorption of oil from produced water showed an increased oil adsorption efficiency from 52.7% to 71% for the alkali-treated CB. The kinetic study showed that during the first 60 min of the adsorption process, maximum adsorption occurred following the pseudo-first-order kinetics with a correlation coefficient R 2 > 0.99, indicating the dominance of physical interaction. The results reveal that cuttlefish bone biowaste can be recycled as an effective adsorbent for produced water treatment. Graphical Abstract