Metolachlor-adsorption on the walnut shell biochar modified by the fulvic acid and citric acid in water

In this study, we used fulvic acid (FA) and citric acid (CA) to soak walnut shell powder. The soaked walnut shell powder is then burned at 700 degrees C into biochar (BC). The modified BC is due to the removal of metolachlor (MET) in the aqueous solution. Firstly, in the study of kinetics and isotherm, it was found that the optimal modified concentrations of FA and CA on BC were both 800 mg L-1. Then characterize the BCs (FBC and CBC) with the best modification effect (SEM, FTIR, XRD). The element composition and surface functional groups of FBC and CBC are analyzed. According to the Langmuir model, the maximum adsorption capacity of FBC and CBC are 99.01 mg g(-1) and 74.07 mg g(-1), respectively, which are significantly higher than the original OBC (51.28 mg g(-1)). It can be seen that both FBC and CBC have good adsorption performance, but the adsorption effect of FBC is better. Finally, the results of adsorption regeneration experiments in agricultural wastewater show that FBC and CBC not only have better adsorption in agricultural wastewater, but also have good regeneration performance. These results help to study the adsorption mechanism and process optimization further.

Automated summary

This study utilized fulvic acid and citric acid to modify walnut shell powder, resulting in biochar with enhanced adsorption performance. The modified biochar showed significant adsorption capacity and regeneration capability in agricultural wastewater, providing valuable insights for further research on adsorption mechanisms and process optimization.