Vachellia nilotica sawdust-derived polymeric and magnetic biocomposites for phosphate ions removal: Kinetics, isothermal, and thermodynamic studies

Abstract

Phosphorus is an important element for both animals and plants, but its excess can cause eutrophication in water. Excess phosphorus is present in wastewater mainly due to acid rain, the dissolving of rocks, and agricultural waste. There are many methods for the elimination of Phosphorus from aqueous solution, but their use is finite because of the high operational cost. Adsorption is a productive and popular method for removing phosphorus from aqueous solution. In this study, Vachellia nilotica sawdust and its different composites (Ppy/SD and MG/SD) were utilized for the effective adsorption of phosphorus from the solution. Prepared sorbents were characterized via BET, SEM, FTIR and XRD for their surface area and morphological, functional and crystallinity attributes. Adsorption tests were carried out to identify the optimal working parameters such as adsorbent dose, temperature, initial phosphorus concentration, pH, and contact time. Adsorption isotherm and kinetic model were accurately explained by the Langmuir model and pseudo 2nd order kinetics. The maximal adsorption capacity for Phosphate was 4.803, 5.32, and 6.27 mg/g for Native/SD, Ppy/SD, and MG/SD, respectively. Thermodynamic characteristics confirmed that the phosphorus adsorption was endothermic and spontaneous. Thus, sawdust is an eco-friendly and inexpensive adsorbent for phosphorus removal from wastewater.