Reactive blue 4 adsorption efficiencies on bagasse and bagasse fly ash beads modified with titanium dioxide (TiO2), magnesium oxide (MgO), and aluminum oxide (Al2O3)

Abstract

Wastewater contaminated by dyes is concerned because of their toxicity to aquatic organisms as well as damaging water source scenery and creating water pollution from the death of aquatic plants from lack of sunlight. Thus, wastewater treatment is highly recommended below water quality standards before discharging to the water body. Eight dye adsorbent materials of bagasse beads (BB), bagasse fly ash beads (BFB), bagasse beads mixed titanium dioxide (BBT), bagasse fly ash beads mixed titanium dioxide (BFBT), bagasse beads mixed magnesium oxide (BBM), bagasse fly ash beads mixed magnesium oxide (BFBM), bagasse beads mixed aluminum oxide (BBA), and bagasse fly ash beads mixed aluminum oxide (BFBA) were synthesized and their sizes of surface area, pore volumes, pore sizes, surface morphologies, chemical compositions, and functional groups were investigated by Brunauer-Emmett-Teller (BET), Zetasizer Nano, Field Emission Scanning Electron Microscopy and Focus Ion Beam (FESEM-FIB), Energy Dispersive X-Ray Spectrometer (EDX), and Fourier Transform Infrared Spectroscopy (FTIR) techniques. Batch experiments were used to investigate reactive blue 4 (RB4) dye removal efficiencies, and their adsorption isotherms and kinetics were studied. BFBM illustrated the highest surface area and the smallest pore size with comparing to other materials. The pore sizes of all dye adsorbent materials were classified into mesoporous sizes that corresponded to particle size analysis (PSA). All dye adsorbent materials had a spherical shape with coarse surfaces. Five main elements of oxygen, carbon, calcium, chlorine, and sodium, and five main function groups of O–H, C O, N O, C–H, and C–O–C were detected in all materials. For batch tests, they could remove RB4 dye by more than 71%, and BFBM represented the highest RB4 dye removal efficiency at 93.78%. Freundlich model was good explained the adsorbent pattern of almost materials except for BB and BFB, and the pseudo-second-order kinetic model well explained their adsorbent mechanisms. Therefore, the addition of metal oxide is recommended for improving material efficiency, and all dye adsorbent materials are good to offer for further industrial applications. • Bagasse and bagasse fly ash were used to synthesize dye adsorbent materials. • All dye adsorbent materials had highly RB4 removal efficiency of more than 71%. • The addition of metal oxides of TiO 2 , MgO, and Al 2 O 3 increased material efficiencies. • Almost materials corresponded to Freundlich and pseudo-second-order kinetic models. • Dye adsorbent materials were potential materials for further industrial applications.