An efficient and optimal adsorptive removal of glufosinate ammonium from wastewater using carbonized rice husk-clay blend briquettes

The persistence of glufosinate ammonium in agricultural runoff poses serious environmental and public health risks, necessitating the development of low-cost and sustainable remediation strategies, since most of the existing solutions such as the advance oxidation and electro-sorption methods are quite expensive, requiring technical expertise to be implemented.This study investigated the adsorptive removal of glufosinate ammonium from wastewater using carbonized rice husk-clay blend briquettes, a valorized agricultural byproduct.Response Surface Methodology (RSM) version 13 of the design expert was employed to optimize key operational parameters, including pH, temperature, contact time, and adsorbent dose.The adsorbent was characterized pre-and post-adsorption using Fourier transform infrared spectroscopy (FTIR), energy dispersive x-ray spectroscopy (EDX), scanning electron microscopy (SEM), and transmission electron microscopy (TEM).The FTIR analysis revealed shifts in characteristic peaks associated with functional groups such as -OH, -CC-, C-H, and C-N, confirming active sites for adsorption.Likewise, the SEM and TEM images showed well-defined porous structures, which became saturated after adsorption, while EDX detected the presence of additional elements, such as Fe and Cu, introduced from the wastewater matrix.Under optimal conditions (pH 7.5, 20 C, 1.25 g adsorbent dose, and 100 min contact time), a removal efficiency of 90% was achieved.The adsorption kinetics followed a pseudo-second-order model (k = 0.09 min), while the equilibrium data conformed to the Freundlich isotherm, indicating multilayer adsorption on a heterogeneous surface.These results demonstrate that rice husk-clay briquettes offer a promising, and sustainable solution for the efficient removal of glufosinate ammonium from contaminated water.