Evaluation of Nitrate Sorption Potential from Aqueous Solution Using Common Reed-Iron Modified Biochar

In recent years using modified biochar has been considered as an adsorbent to removal of inorganic pollutants such as nitrate from aqueous solution. Because of the increase of nitrate concentration in water resources and its environmental consequences, in this study the efficiency of nitrate adsorption by iron-modified common reed biochar from aqueous solution was investigated. For this purpose common reed biomass was modified by one molar iron chloride solution and then pyrolyzed at 500 °C and its physicochemical characteristics were measured. Nitrate adsorption was evaluated in batch experiments. The results indicated that the yield, cation exchage capacity (CEC), anion exchange capacity (AEC) and surface area of the biochar increased through modification by iron chloride. The adsorption efficiency of nitrate increased by increasing contact time, but it reduced by increasing initial concentration of nitrate in the solution. The pseudo-second-order kinetics model provided a good description for adsorption processes of biochar produced at 500 ºC (R2= 0.98) and iron modified biochar (R2= 0.99). Among the adsorption isotherms, Langmuir model (R2= 0.99) illustrated the best fit with the experimental data for both biochars. In general, the results of this study showed the high potential of iron-modified biochar for nitrate sorption (81.30 mg g-1). Thus, it could be concluded that the iron-modified biochar has high potential for nitrate removal from aqueous solutions.