Eco-Friendly Remediation of Adsorbed Chlorsulfuron Herbicide via Walnut Shells Derived Activated Carbon

Chlorsulfuron (1-(2-chlorophenyl) sulfonyl-3(4-methoxy-6-methyle-1,3,5-triazin-2-yl)) is the primary commercialized sulfonylurea weedicide aimed at combating several leafy weeds for the protection of many cereals and potato crops. It is used as a pre as well as a post-emergent weedicide. Due to its organic ringed structure, it poses serious environmental degradation, particularly in the lithospheric compartment. The present investigation has analyzed its adsorptive interactions with soils inherently composed of unique physicochemical attributes. In a batch equilibrium experiment, sample 2 expressed the highest adsorption coefficient Kd(ads) with overall adsorption spanning over a range of 6.78 to 39.85 μg/mL. Adsorptive capacity analysis via Linear and Freundlich models yielded R^2 0.8 indicative of best fitting of these models to Chlorsulfuron adsorption. Statistical analysis showed a negative correlation between soil pH and Kd(ads) (R^2= -0.85) and a positive correlation with organic matter (R^2= 0.96). The data was further analyzed by univariate ANOVA and its accuracy was checked through residual plots. Furthermore, the adsorbed Chlorsulfuron was remediated via the green method by utilization of walnut shells derived activated carbon in varying concentrations of 5 ppm and 7.5 ppm of Chlorsulfuron. The highest removal in 5 ppm was observed in soil 9 (85%) while in 7 ppm highest removal was observed in soil 2 (91%). Current investigation not only explored the adsorptive pattern of Chlorsulfuron but also developed a non-toxic, eco-friendly, pragmatic, and economical adsorbent for its removal.