Influence of Nano biochar on the fate and transport of chlorpyrifos

Geochemical aging can alter the chemical structure of biochar (BC), resulting in the release of nano sized BC (ranging from 200 nm to 500 nm).  Although, several studies have revealed the adsorption and immobilization of pesticides on BC, little is known regarding the mobility and retention of pesticides sorbed on nano particles. Thus, column tests were conducted to investigate organophosphate pesticide (chlorpyrifos) transport using nano biochar (NBC) as amended in sand column and use Hydrus 1D model to simulate the result. The findings demonstrated that NBC amended sand increased chlorpyrifos retention by 60% to 70% when nanoparticles were incorporated. Additionally, the chlorpyrifos simulated k_d value (sorption coefficient) increased from 1.64 L/g to 2.10 L/g. Also, the proportion of equilibrium adsorption sites (f) decreased from 0.25 to 6.78 ×10^-6 after amendment. This study shows that Nanoparticles maximizes the efficiency of biochar in controlling environmental pollution by improving its adsorption capacities and modulating its ability to prevent pesticide migration to groundwater.

Keywords: Organophosphate transport, HYDRUS-1D, soil column, non-equilibrium equation, adsorption