Investigation on boron removal from produced water utilizing cassava stem biochar: Understanding from equilibrium, kinetics, thermodynamics and characterization

The present study investigates the potential of an agricultural by product cassava stem biochar, as an effective adsorbent for the removal of boron from produced water. Cassava stem biochar was prepared through controlled pyrolysis, and adsorption experiments were conducted to evaluate the removal of boron ions from produced water, considering parameters, such as pH (1–8), contact time (0–45 min), initial concentration of boron in produced water (1.3–3.8 mg/L), adsorbent dosage (0.25–1.5 g/L), temperature (20–40 °C), agitation speed (50–250 rpm) and particle size (125–2000 μm). The results revealed that cassava stem biochar exhibited a significant adsorption capacity of 3.42 mg/g for the removal of boron ions, with a notable influence of solution pH, contact time, adsorbent dosage, temperature, agitation speed, and particle size of 6, 35 min, 1.25 g/L, 25 °C, 100 rpm, and 250 μm, respectively. Freundlich isotherm and pseudo-second order kinetic models were applied to elucidate the adsorption mechanism. Thermodynamic parameters were also determined to gain insights into the energetics of the adsorption process, and it is exothermic, feasible, and spontaneous. Hence, this study contributes to the development of cost-effective adsorption for the remediation of boron-contaminated water.