Composite of iron phosphate-supported carbon from the açaí (Euterpe oleracea) as a solid catalyst for photo-Fenton reactions

• DOI: 10.1016/j.enmm.2021.100520
• Publication Date: 2021-07-04T13:44:38Z
• Authors: Vera L.I. Bentes; Francisco X. Nobre; Ivoneide C.L. Barros; Paulo R.C. Couceiro
• Keywords: Phosphoric acid; Iron phosphate; Carbon fibers

Abstract This work reports on obtaining iron phosphate-supported from activated carbon derived from the acai fruit (Euterpe oleracea Mart.) waste, with H3PO4 and Fe(NO3)2 as precursors. The samples were well-prepared by thermal decomposition at 400 °C (CP-400) and 500 °C (CP-500) with biomass, phosphoric acid, and iron nitrate ratio of 1:1:1 (wt/wt/wt). We characterized the products by X-ray diffraction, confirming the phase mixture of Fe(PO3)3 metaphosphate (P21/n), Fe2P4O12 tetrametaphosphate (C2/c), and amorphous carbon. All active modes were identified for biomass and iron phosphates in infrared spectroscopy. SEM images showed several irregular agglomerates formed by iron phosphate in both samples, where carbon (C), oxygen (O), iron (Fe), and phosphorus (P) were detected in the EDX analysis. The resulting N2 adsorption/desorption obtained isotherms were classified as type I (CP-400) and II (CP-500), with a surface area of 303 m2 g−1 and 206 m2 g−1, respectively. The adsorption of methylene blue dye (MB) in the aqueous solutions of composites CP-400 and CP-500 were 40 mg g−1 and 50 mg g−1, respectively. The photo-Fenton reaction using these composites as solid catalysts showed 99.6% of discoloration for CP-400 and 97.5% for CP-500, at 240 min under UV-light.