Synthesis of Flower-Like Iron Oxide/Hydroxide on Rice Husk Ash Support and Its Application for Phosphate Removal in Water

• Published in: Journal of water chemistry and technology 2021, Vol.43 (2), p.108-115
• Main Authors: Phuoc Toan Phan, Nguyen, Trung Thanh, Le, Tri Thich, Le, Ngoc Hang, Padungthon, Surapol, Nguyen, Nhat Huy
• Format: Article
• Language: English
• Subjects: Adsorption; Advanced wastewater treatment; Analytical methods; Aquatic Pollution; Aqueous solutions; Bottom ash; Chemical precipitation; Corrosion; Earth and Environmental Science; Electron microscopy; Environment; Ferric oxide; Flowers; Fourier transforms; Hydroxides; Industrial Chemistry/Chemical Engineering; Infrared spectroscopy; Iron oxides; Iron sulfates; Kilns; Morphology; Phosphate; Phosphates; Phosphorus removal; Physical Chemistry of Water Treatment Processes; Removal; Rice; Scanning electron microscopy; Spectrum analysis; Surface chemistry; Urea; Waste utilization; Waste Water Technology; Wastewater treatment; Water Industry/Water Technologies; Water Management; Water pollution; Water Pollution Control; Water Quality/Water Pollution; X rays; X-ray diffraction; X-ray spectroscopy
• ISSN: 1063-455X; 1934-936X
• DOI: 10.3103/S1063455X21020090

Phosphorous is one of the essential elements for living-forms on the Earth; however, the excessive presence of phosphate in the environment causes water pollution. Several methods have been developed and applied for phosphate removal in wastewater and adsorption is considered as a low-cost, simple, and stable technology for wastewater with low phosphate concentration. Although several mesoporous materials have been used as adsorbents, there has not been any report on the utilization of rice husk ash as support for iron oxide/hydroxide growth toward phosphate removal. In this study, flower-like iron(III) oxide/hydroxide on activated rice husk ash support (Fe-ARHA) was synthesized and applied as a novel material for phosphate removal in aqueous solution. ARHA was prepared by the chemical corrosion method with HF acid using bottom ash of a brick kiln using rice husk as fuel. Flower-like iron oxide/hydroxide was then grown on the surface of ARHA by precipitation of iron(III) sulfate using urea solution. The materials were then characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy to explore their properties. The mechanism for the formation and growth of flower-like iron oxide/hydroxide on the ARHA surface was proposed. In batch phosphate removal test, Fe-ARHA with Fe/ARHA ratio of 5 : 3 showed the highest adsorption capacity of 37.8 mg/g, which could be due to the interaction between iron oxide/hydroxide and ARHA support. This flower-like morphology and the interaction let more iron oxide/hydroxide surface be exposed to the water environment and effectively serve as adsorption sites for phosphate removal. These results prove the potential for the utilization of waste rice husk ash and iron oxide for water and advanced wastewater treatment applications.