Highly efficient removal of phosphate from aqueous media by pomegranate peel co-doping with ferric chloride and lanthanum hydroxide nanoparticles

The low phosphate content in the surface water is considered a pollutant that promotes algae reproduction and leads to eutrophication. Bimetallic Fe/La nanoparticles doped on pomegranate fiber (Fe/La Peel) were fabricated by solvothermal synthesis method and applied as biosorbent for phosphate removal in this study. Fe-La/Peel had an irregular and rough surface with a specific surface area of 93.18 m(2)/g and its surface was uniformly covered with Fe and La, providing potential adsorption sites for phosphate uptake. At the pH 2.91, the highest capacity of Fe/Peel, La/Peel and Fe-La/Peel were 13.91 mg/ g, 38.86 mg/g and 44.5 mg/g, respectively. Batch adsorption experiments indicated that Fe-La/Peel biosorbent had excellent adsorption ability. In batch adsorption experiment, highest adsorption capacities of Fe-La/Peel fitted by Langmuir and Sips isotherms were 75.09 mg/g and 78.99 mg/g at 323 K, respectively. The total lowest metal leaching of Fe/La Peel was found 0.054 mg/mL under alkali condition, and the highest metal leaching was determined 8.13 mg/mL under acidic condition. The adsorption performance of Fe/La Peel was better than those La/Peel and Fe/Peel at the same pH levels. Phosphate capture by Fe-La/Peel bio-nanocomposite was a homogeneous adsorption process and increased capacity with the rising temperature. At neutral pH, phosphate uptake by Fe-La/Peel could maintain high efficiency and metal leaching was almost negligible. The preferential phosphate adsorption by Fe-La/ Peel can also be achieved in the same magnitudes of coexisting anions (Cl-, NO3-, HCO3-). And the adsorption capacity was reduced to less than 20% in the presence of electrolytes. These results showed that Fe-La/Peel has the potential to be used for environmental remediation to remove phosphate from the wastewater. (C) 2020 Elsevier Ltd. All rights reserved.