Removal of boron from aqueous solution by adsorption using calcined magnesite

In this study, boron removal from aqueous solutions by adsorption using calcined magnesite obtained from KÜMAŞ Magnesite Inc. was investigated. The effects of adsorbent amount, pH, contact time, initial solution concentration and temperature parameters affecting the adsorption mechanism on the removal efficiency were investigated. The adsorbent was characterized by XRD, XRF, SEM/EDS and FTIR techniques. The kinetics, isotherm and thermodynamics of the adsorption process were investigated. It was determined that the most suitable adsorbent amount was 1 g for boron removal from 50 mL solution with an initial concentration of 500 mg B/L. It was observed that the removal efficiency decreased significantly at pH values above 8. It was found that the adsorption process reached equilibrium in 24 hours. The removal efficiency increased with decreasing initial concentration and and increasing temperature. It was determined that the adsorption process obeyed the Langmuir isotherm model and the pseudo-second-order kinetic model. The maximum adsorption capacity at 25oC was found to be 34,48 mg/g. In addition, it was determined that the adsorption process was endothermic, spontaneous and increased randomness. As a result, it was concluded that calcined magnesite can be used as an efficient and low-cost adsorbent in removing boron from aqueous solutions.