Preparation of magnetic biochar for nitrate removal from aqueous solutions

The present paper presents the evaluation of the adsorption efficiency and adsorption capacity for nitrate removal of magnetic biochar derived from corn stalk prepared by pyrolysis process. Characterization of magnetic biochar have been performed by TGA, XRD, FT-IR and BET methods. The results indicate that the adsorbent has a mesoporous structure graphed with O-H and COOH groups. The effect of various parameters such as pH, mass of Fe3O4-BC adsorbent, contact time, and nitrate concentration on the adsorption process of nitrate were studied. The ranges investigated were pH 4-10, concentration 50-300 ppm, the amount of activated carbon 0.15-0.35 g and contact time 30-120 min. The experimental data show that the prepared magnetic biochar has a nitrate removal efficiency of 98.91% at pH, 50 ppm nitrate concentration, 0.25 g adsorbent and 120 min. The adsorption capacity of the Fe3O4-BC adsorbent was studied by using Response Surface Methodology based on a Box-Behnken design (BBD). The optimum conditions for the equilibrium adsorption capacity (q(e)) calculated at pH 7, 300 ppm nitrate concentration, 0.15 g adsorbent and 30 min was validated by experimental data and the results are in agreement with the experimental data.

Automated summary

The present study evaluated the adsorption efficiency and capacity of magnetic biochar derived from corn stalk for nitrate removal. The effects of various parameters on the adsorption process were investigated and the experimental data showed high nitrate removal efficiency. Response Surface Methodology was used to study the adsorption capacity and the optimal conditions were validated by experimental data.