Removal of 2,4-Dichlorophenolyxacetic acid (2,4-D) herbicide in the aqueous phase using modified granular activated carbon

Background: low cost 2,4-dichlorophenolyxacetic acid (2,4-d) widely used in controlling broad-leafed weeds isfrequently detected in water resources. the main objectives of this research were focused on evaluating thefeasibility of using granular activated carbon modified with acid to remove 2,4-d from aqueous phase,determining its removal efficiency and assessing the adsorption kinetics.results: the present study was conducted at bench-scale method. the influence of different ph (3–9), the effectof contact time (3–90 min), the amount of adsorbent (0.1-0.4 g), and herbicide initial concentration (0.5-3 ppm) on2,4-d removal efficiency by the granular activated carbon were investigated. based on the data obtained in thepresent study, ph of 3 and contact time of 60 min is optimal for 2,4-d removal. 2,4-d reduction rate increasedrapidly by the addition of the adsorbent and decreased by herbicide initial concentration (63%). the percent of2,4-d reduction were significantly enhanced by decreasing ph and increasing the contact time. the adsorption of2,4-d onto the granular activated carbon conformed to langmuir and freundlich models, but was best fitted totype ii langmuir model (r2 = 0.999). the second order kinetics was the best for the adsorption of 2,4-d by modifiedgranular activated carbon with r2 > 0.99. regression analysis showed that all of the variables in the process havebeen statistically significant effect (p < 0.001).conclusions: in conclusion, granular activated carbon modified with acid is an appropriate method for reducingthe herbicide in the polluted water resources.