Mesoporous θ-Alumina/Hematite (θ-Al2O3/Fe2O3) Composite Nanofibers for Heavy Metal Removal

theta-alumina/hematite (theta-Al2O3/Fe2O3) composite nanofibers were synthesized via electrospinning followed by calcination and optimized towards heavy metal removal (i.e., Cr(VI)). The composite nanofibers were characterized for their morphological and materials properties and tested in aqueous solutions containing chromate (CrO42-) to analyze their adsorption performance. Although, synthesized nanofibers have similar average diameter from 23 to 26 nm independent of the composition, BET analysis showed an increase in specific surface area with increasing Al content from 59.2 to 92.8 m(2)/g. This suggests the synergy of theta-Al2O3 and Fe2O3 causing increased surface roughness and greater porosity. The CrO4-2 adsorption capacity increased with increase in Al content. For example, theta-Al2O3/Fe2O3 nanofibers with 32 wt.% of Al have an adsorption capacity of 169.5 mg/g, which is twice the value of the pure Fe2O3 nanofibers and over a 3-fold increase compared to the commercial Fe2O3 nanoparticles. The study shows that the composite of hematite and theta-alumina has better physical properties (e.g., larger surface area, smaller pore size, larger pore volume, etc.) and, in turn, enhanced adsorption removal of heavy metal pollutants.