Effect of Magnetite Oxide Nanoparticles and Tungsten Oxide Nanoparticles on Phosphate Removal from Aqueous Solutions

Phosphate (P) removal from aqueous solutions were studied by a new mineral adsorbent, tungsten (VI) oxide (WO3) nanoparticles (NPs), which has not been the subject of much research in the field of removing P contaminants from agricultural wastewater. In this paper, P was removed from aqueous solutions by a new mineral adsorbent, WO3 NPs and it was compared with magnetite (iron (IV)) oxide) (Fe3O4) nanoparticles (NPs) under the same ambient operating conditions i.e., The influence of the dosage of adsorbents, initial P concentration, contact time, pH and temperature. The values that achieved the best removal were recorded. It was concluded that the best limits for pH were at 2-3, contact time at 40 minutes, temperature at 45°C and adsorbent dose at 1.0 g/L. Best results of the variables were applied on samples of real agricultural wastewater, which achieved removal ratio of 77.3% and 75.42% for Fe3O4 and WO3 NPs, respectively. SEM, EDX and FTIR images and analyses were conducted to describe the characteristics of nano-adsorbents used before and after P adsorption in aqueous solutions. The P adsorption kinetics for aqueous solutions were examined by fitting results of the experiment to both the first & second pseudo-kinetically models. The outcome indicated that kinematic data fit better with pseudo-second-order kinetic models. Moreover, the information captured from equilibrium adsorption was analyzed using isothermal methods (by Langmuir & Freundlich Forms). Their results showed that the Freundlich form is considered more suitable than Langmuir form in analyzing the biosorption of P ions. The thermodynamic demeanor of P adsorption by Fe3O4 and WO3 NPs was analyzed and evaluated, and the thermodynamic data analyses confirmed the process of P adsorption was spontaneous. The ΔG° value was negative, while ΔH° and ΔS° values found to be positive, which means that the adsorption of P was a spontaneous, random and endothermic operation. In general, Fe3O4 and WO3 nanoparticles had a high efficiency in removing phosphate from water. In addition, WO3 NPs has been identified as one of the most promising adsorbents due to its rapid and effective adsorption of pollutants