Agricultural activities are essential for sustaining the global population, yet they exert considerable pressure on the environment. A major challenge we face today is agricultural pollution, much of which is diffuse in nature, lacking a clear point of origin for chemical discharge. Modern agricultural practices, which often depend on substantial applications of fertilizers, pesticides, and irrigation water, are key contributors to this form of pollution. These activities lead to downstream contamination through mechanisms such as surface runoff, leaching, soil erosion, wind dispersal, and sedimentation. The environmental and human health consequences of diffuse pollution are profound and cannot be ignored. Accurate assessment of the risks posed by agricultural pollutants is crucial for ensuring the production of safe, high-quality food while safeguarding the environment. This requires systematic monitoring and evaluation of agricultural practices, including soil testing and nutrient management. Furthermore, the development and implementation of best management practices (BMPs) are critical in reducing the levels of agricultural pollution. Such measures are essential for mitigating the negative impacts on ecosystems and public health. Therefore, the adoption of preventive strategies aimed at minimizing pollution and its associated risks is highly recommended to ensure long-term environmental sustainability and human well-being.

Adsorption has been considered as a promising remediation technology to separate organic and inorganic agrochemicals from contaminated soil and water. Low-cost adsorbents, including waste derived materials, clay composites, biochar, and biochar modified materials, have attracted enormous attention for the removal of organic contaminants, including pesticides. In this study, iron-modified base-activated biochar (FeBBC) was prepared by pyrolysis (at 400 °C for 1 h) of iron-doped base (KOH) activated sugarcane bagasse for the removal of a widely used insecticide, namely imidacloprid (IMI) from water. The maximum adsorption capacity of the adsorbent (FeBBC) was calculated as 10.33 (± 1.57) mg/g from Langmuir isotherm model. The adsorbents could remove up to ~ 92% of IMI from aqueous solution at 23.8 mg/L IMI. Experimental data fitted well with the Freundlich model and pseudo-second-order model, demonstrating physisorption, as well as chemosorption, contributed to the sorption process. Even at highly acidic/basic solution pH, the FeBBC could remove substantial amount of IMI demonstrating hydrophobic interaction and pore diffusion play vital role for removal of IMI. The slight improving of IMI sorption with increasing solution pH indicated the sorption was also facilitated through ionic interaction alongside physical sorption. However, physical sorption including hydrophobic interaction and pore-filling interaction plays a vital role in the sorption of IMI.