Thermodynamic Study of Phosphate Adsorption and Removal from Water Using Iron Oxyhydroxides

Iron oxyhydroxides (FeOOHs) appear to be the optimal group of materials among inorganic adsorbents for removal phosphates from water, providing significant adsorption capacities. This research work presents a thermodynamic study phosphate by examining five different FeOOHs sorbent nanomaterials. The otablebtained results indicated that process in these cases was spontaneous. When experiments were performed using distilled akageneite (GEH), schwertmannite, and tetravalent manganese feroxyhyte (AquAsZero), displaying ΔH° values 31.2, 34.7, 7.3 kJ/mole, respectively, presented an endothermic process, whereas goethite (Bayoxide) lepidocrocite, with −11.4 −7.7 proved exothermic. However, when artificial (according NSF) water matrix used, GEH, AquAsZero 13.2, 3.3, 7.7, 3.3 indicative while only Bayoxide, −17 remained enthalpy generally decreased NSF matrix, probably due competition same sites other co-existing anions as well possible formation soluble complexes calcium; however, overall positive effect on uptake observed.