Regenerable magnetic aminated lignin/Fe3O4/La(OH)3 adsorbents for the effective removal of phosphate and glyphosate

Phosphates and organophosphorus cause environmental pollution, and excessive phosphate leads to water eutrophication. Glyphosate, an organophosphorus herbicide, harms the environment and human health. In this study, regenerable magnetic AL/Fe3O4/La(OH)3 adsorbents were developed by modifying Fe3O4 and La(OH)3 on aminated lignin (AL) for phosphate and glyphosate removal. The adsorption capacity for phosphate and glyphosate reached 60.36 mg g-1 and 83.87 mg g-1 when the initial concentrations were 150 mg L-1 and 250 mg L-1, respectively. The thermodynamic data showed that adsorption is a spontaneous and endothermic process. Adsorption can be applied at pH values ranging from 3 to 11 and is more suitable under acidic conditions. Fe3O4 and La(OH)3 both enhanced the adsorption capacities of phosphate and glyphosate. Phosphate and glyphosate compete slightly when coexisting in the adsorption process at low concentrations. Due to the magnetic properties of Fe3O4, the adsorbents can be separated rapidly and effectively with an external magnetic field. 89% adsorption capacity remained after four adsorption-desorption recycles. Thus, AL/Fe3O4/La(OH)3 shows potential for phosphate and glyphosate removal as an effective and reusable adsorbent.