Comparative study of biochar prepared from cow dung and sewage sludge and its application as an adsorbent for organic pollutants removal in water

In this research, the synthesis of biochar from cow dung and sewage sludge and its application for the removal of organic contaminants using methylene blue (MB) as the model molecule was evaluated. Experiments were performed using different concentrations of adsorbent and MB and were optimized by a response surface methodology (RSM). Dynamic models were adjusted to the experimental data and the regeneration of the bed was studied. The results showed that the optimal conditions to favor the adsorption of MB, in a fixed bed and making a comparison between the two biochar sources, were those where an adsorbent biochar concentration of 5 g and initial MB concentration of 10 mg L-1 were used. The biochar prepared from cow dung presented the best adsorption conditions. Under these conditions, the breaking time was 172.73 min. The models of Thomas, Bohart-Adams, and Yoon-Nelson were applied for the study in fixed-bed columns and it was observed that the models were adjusted satisfactorily. Regeneration was possible for three different cycles, slightly diminishing the performance of the bed with elution of HNO3. These results indicate that MB bed fixed adsorption on cow dung biochar is viable and suitable for water treatment.

Automated summary

The study found that biochar prepared from cow dung performed the best in removing organic contaminants, with the optimal conditions being using 5g of adsorbent biochar and an initial MB concentration of 10mg/L. Regeneration of the bed was possible for three cycles, but slightly diminished the bed performance with elution of HNO3.