Removal of Glyphosate from water through adsorption onto Goethite Nanoparticles

Abstract

The adverse effects of prolonged exposure to Glyphosate for human, animal and aquatic life have gained significant attention in recent years. The application of Glyphosate over the past four decades has resulted in the detection of the organophosphorus herbicide in many waterways. Conventional water treatment processes are inefficient for removing this highly hydrophilic compound. However, adsorption processes have emerged as a potential process for removing organic contaminants from aqueous matrices. This study involved the synthesis of Goethite Nanoparticles via a co-precipitation reaction as an adsorbent material for Glyphosate. The Goethite Nanoparticles were characterized by X-Ray Diffraction, Fourier-Transform Infrared Spectroscopy and Scanning Electron Microscope images. The X-Ray Diffraction spectrum was in similar agreement to JCPDS file for Goethite (JCPDS 29-0713) with an average crystallite size determined by the Scherrer formula of 8.87 nm. Adsorption studies conducted in Glyphosate spiked solutions were utilized to determine the optimum operating conditions. Adsorption was optimum in slightly acidic conditions (pH 5) with an equilibrium time of 8 h. Adsorption kinetics and isotherms were applied to the adsorption data. The data best fit the pseudo-second-order kinetics equations indicating the presence of chemisorption processes. A Langmuir's Adsorption Capacity of 277.77 mg/g was calculated subsequently agreeing to experimentally derived values.