Organosilane grafted acid-activated beidellite clay for the removal of non-ionic alachlor and anionic imazaquin

► We prepared clay adsorbents via two-step method to remove nonionic alachlor and anionic imazaquin herbicides from water. ► Layered beidellite clay was treated with acid in hydrothermal process with common silane coupling agents. ► It was found that the selective modification of clay samples displayed higher adsorption capacity for herbicides compared with acid activated clay. ► Clay grafted with 3-chloro-propyl trimethoxysilane is an excellent adsorbent for both alachlor and imazaquin. ► Triethoxy (octyl) silane grafted clay is more efficient only for alachlor removal.