A Comprehensive study on adsorption kinetics and equilibrium: Utilizing olive mill by-products as a sustainable biosorbent for cobalt (II) removal

Aiming to remove cobalt from wastewater in a sustainable manner, this work marks a major advancement in industrial and technological advancements. We study if dried olive mill solid residues (DOMSR), a byproduct of the olive oil business, may effectively remove Co(II) ions from aqueous solutions by acting as a biosorbent. We have been able to offer useful insights by carefully analyzing the adsorption process and optimizing crucial variables such contact time, pH levels, initial metal concentration, and adsorbent dosage. Our experimental results demonstrate that higher initial cobalt concentrations increased the adsorption capacity, reaching a maximum of 120 mg/L. At pH 6.0, the maximum removal percentage was 82%, and the optimum adsorption achieved after 40 min of contact time. The adsorption process was best described by the pseudo-second-order model, according to kinetic studies, suggesting that chemisorption is the rate-limiting stage. The best fit was given by the Langmuir isotherm model (R2=0.9948), which indicated homogenous active sites and a maximal sorption capacity (Qm) of 41.84 mg/g. This research underscores the potential of agricultural waste-based biosorbents like OMSR for efficient cobalt removal, thereby offering a valuable contribution to sustainable wastewater treatment practices and environmental conservation.