Abstract
Water pollution by organic dyes poses great challenge to the environment and living organism. Hence effective removal of organic dyes by cost effective methods have received significant attention in recent years. Herein, we report the complete removal of organic dyes (rhodamine B), methylene blue) and eosin yellow) from water via effective adsorption by MoO3 catalyst. Hydrothermally synthesised MoO2 (1) and amorphous MoSx (2) using ammonium molybdate without and with thiourea exhibited low dye adsorption. In contrast, crystalline micro/nanoplates of MoO3 (3 and 4) obtained from calcination of 1 and 2 showed highly enhanced dye adsorption. Particularly 4 showed higher dye adsorption compared to 3. UV–Visible absorption studies confirmed complete removal of organic dyes upon stirring with MoO3 catalyst. Dye removal studies further revealed that cationic dyes are adsorbed faster than anionic dye that could be attributed to the surface charge of MoO3. Interestingly, the adsorbed dyes were not released from MoO3 for more than 50 days. The exhausted MoO3 catalyst can be recovered by annealing at 400 °C. MoO3 catalyst has also been used as packing materials in dropper column and demonstrated effective removal of dyes by passing through dyes separately as well as mixture.
MoO3 nanoplates/rods prepared by hydrothermal-calcination method exhibited superior dye adsorption while stirring as well as filtration. [Display omitted]
•Fabricating nano/micro plates of MoO3 via hydrothermal-calcination method.•Highly enhanced dye adsorption by MoO3 nano/micro plates fabricated from MoSx.•Easy removal of mixed dyes by filtration using dropper column.•Regenerating used MoO3 adsorbent by calcination.