Simultaneous optimization of production yield and sulfadiazine adsorption of MgFe₂O₄ loaded on prickly pear biochars using Box-Behnken design

A major challenge that humans facing is the uncontrolled discharge of antibiotic-containing wastewater into the environment, accompanying with huge threats to human community. The utilization of cost-effective biomass-based adsorbents is considered a potential solution for the treatment of antibiotic wastewater. This study aims to optimize the synthesis of MgFe₂O₄ nanoparticles loaded on prickly pear biochar (PPB) with outstanding sulfadiazine adsorbability using response surface methodology. Thirteen materials (MgFe₂O₄-PPB) produced based on Box-Behnken design were tested to evaluate the impact of the main factors on the material preparation process, including ratio of MgFe₂O₄:PPB precursors, calcination temperature and calcination time. Under optimized conditions, i.e., MgFe₂O₄:PPB ratio 0.5, temperature 600 °C and time 1 h, the production yield of 46.5% and sulfadiazine removal percentage of 85.4% were obtained. Characterization of optimized MgFe₂O₄-PPB indicated the good porosity and functionality suitable for the adsorption of sulfadiazine. Elovich model showed the best description of kinetic process. Temkin model was considered to be an accurate description of the isotherm adsorption. Proposed mechanism for antibiotic adsorption onto MgFe₂O₄-PPB was described. We clarify cost-benefit analysis to asses the importance of MgFe₂O₄-PPB as well as the economic and environmental impacts of biochar-based composites.