Mechanical activation of TiO2/Fe2O3 nanocomposite for arsenic adsorption: effect of ball-to-powder ratio and milling time

Arsenic contamination and its removal from the ground or natural water become an inevitable research line as it is highly carcinogenic and toxic. In the last few decades, nanotechnology has been achieved to provide accessible clean water for all living organisms. In this work, the various ratios of TiO2/gamma-Fe2O3 nanocomposite (T/M NCs) synthesized using the ball-milling route serve as nano-adsorbent for removing arsenic species. This study presents a non-toxic, low-cost, and easily accessible method for synthesizing NCs in large quantities for adsorption, offering promising results for arsenic removal from water. The ball-milling synthesis provides a comparatively, cost-effective strategy and for modulating the properties of nanostructured materials. The milling time and ball-to-powder ratio variations allow modifying the T/M NCs properties during the synthesis. The structural, morphological, and optical characterizations using X-ray diffraction, high-resolution electron microscopy, and UV-Vis analysis showed the formation of predominantly spherical-shaped anatase TiO2 and cubic gamma-Fe2O3 with varying bandgap between 2.06 and 2.14 eV, which changes because of the nanomaterial phase transformation during the milling process. Elemental compositional analysis using EDS showed the uniform distribution of Ti and Fe atoms. The vibrational modes observed using Raman spectroscopy confirmed the presence of anatase TiO2 and gamma-Fe2O3 within the NCs and showed the associated variations with changes in synthesis parameters. X-ray photoelectron spectroscopy analysis of the synthesized ratios indicated a variation in the binding energy (Delta BE) and the evidence of charge transfer in between TiO2 and gamma-Fe2O3 NCs. The adsorption studies using the various T/M NCs ratios show varying performances. The enhanced performances obtained for the NC of anatase TiO2 and gamma-Fe2O3 with the most intense phase peak ratio (I-(101)/I-(311)) of 1.2 and above shows decreased adsorption efficiency with the phase changes into rutile TiO2, hematite, and pseudorutile phases. The elimination of As(III) and As(V) using the synthesized NCs confirms that the ball milling technique can produce nanomaterials with desirable properties for adsorption purposes. Graphic abstract The effect of BPR and milling time on TiO2/gamma-Fe2O3 nanocomposite (T/M NCs) and its impact on Arsenic adsorption.

Automated summary

The study focuses on utilizing ball-milled TiO2/gamma-Fe2O3 nanocomposites as nano-adsorbent for arsenic removal, showing promising and cost-effective results. Various ratios of the nanocomposites were synthesized and characterized for their adsorption efficiency, with the most intense phase peak ratio showing the best performance. The ball-milling technique proves to be effective in producing nanomaterials with desirable properties for adsorption purposes.