Boron Removal from Aqueous Solutions using Composite Adsorbent Based on Carbon-Mineral

Boron removal from aqueous solutions by adsorption was investigated using composite adsorbent that combine zeolite, limestone, activated carbon and rice husk charcoal waste. In this study, the optimum parameters such as pH, optimal contact time and adsorbent dosage were observed. In addition, adsorption isotherm studies and adsorption kinetics were made. In this study, the maximum boron removal was obtained at pH5 and the optimum contact time was 120 min. The optimal dose of composite adsorbent to remove boron in aqueous solutions is about 280 g/L which can remove about 50.49%. In the isotherm studies, Langmuir and Freundlich isotherm models were applied and it was determined that the experimental data conformed to Langmuir isotherm model (R2 = 0.8792). The adsorption capacity (qm) obtained from Langmuir isotherm model was 1.8985 mg/g. Kinetics studies were performed to understand the mechanistic steps of the adsorption process and the rate kinetics for the adsorption of boron was best fitted with the second-order kinetic model. The correlation coefficients obtained for second-order kinetic model was 0.9929. It is suggested that the boron adsorption is likely influenced by the chemical process.