Organophosphorus pesticides, particularly profenofos, present environmental challenges due to their toxicity. Residues of profenofos in farmland water can have adverse effects on ecosystems and human health. Traditional removal methods like chemical oxidation and physical adsorption have been explored, but this study focuses on a more sustainable and effective approach – biodegradation.

The study introduces an innovative method using walnut shell biochar to immobilize Cupriavidus nantongensis X1T, a bacterium with a proven ability to biodegrade organophosphorus pesticides. Immobilization on biochar was achieved through pore filling, van der Waals attraction, and hydrogen bonding, enhancing bacterial viability.

The immobilized X1T displayed remarkable proficiency in degrading profenofos, outperforming free X1T in various conditions. This immobilization method significantly accelerated the expression of the degradation gene opdB, leading to a 5.2-fold reduction in the pesticide’s half-life. The study demonstrates that immobilized X1T maintained an 83% removal efficiency even after six reuse cycles in paddy water.

The research addresses the environmental implications of profenofos residues in agricultural water and highlights the potential of biochar-immobilized X1T for sustainable bioremediation. The biochar not only promotes bacterial viability but also avoids the exposure of toxic degradation products.

In conclusion, the utilization of walnut shell biochar as an immobilization carrier for X1T opens new avenues for efficient and sustainable removal of organophosphorus pesticides from contaminated agricultural water. This approach holds promise for real-world applications, contributing to a more environmentally friendly and economically viable solution to pesticide residue concerns.