Enhanced photocatalytic activity of ZnO nanostructure for water purification

Abstract

Phone: þ331 6095 7276, Fax: þ331 6095 7297A study of the ZnO nanowire array photocatalysis performance has been carried out under UV radiation for the degradation of the toxic organic compounds such as methylene blue (MB), methyl orange (MO), and acid red 14 (AR14) dyes, which are commonly used in textile and pharmaceutics industries. UV-Vis spectrometry has been used to follow the dye degradation characterization. The degradation mechanism has been proposed for each dye, which will give a reasonable explanation about different degradation degree under same experimental conditions. MB and AR14 showed a better degradation performance than MO.

Enhanced Photocatalytic Activity of Iron-Doped ZnO Nanowires for Water Purification

“…Although the AR14 dye also contains the N=N bond, the attracting effect of the OH • radicals on the aromatic ring creates a deficit on the carbon atom in the C-N= bond, which further weakens the C-N bond. The photo-degradation mechanism has been proposed for each dye in our previous work [14] under the same experimental conditions. Iron doping also improved the photocatalytic efficiency for the MB and AR14 depollution, their photo-degradation rate increases from 86% to 95% for MB and from 93% to 98% for AR14.…”

“…The sample of ZnO NWs was placed at the bottom of the container with a fixed dye solution volume of 50 mL. The distance between the UV lamp and the sample surface was maintained at 10 cm for all photocatalysis experiments as shown in our previous work [14]. It is worth noting that during the photocatalytic reaction, there is no stirring in the solution for this study.…”

“…The synthesis of the Fe-doped nanowires was carried out by two-step hydrothermal method: The buffer layer consisting of 2 g of polyvinyl alcohol (PVA) and 0.25 g of zinc acetate dihydrate (Zn(CH 3 COO) 2 ·2H 2 O) dissolved in water, was firstly spin-coated on the substrate as described in our previous work [14]; then the growth of ZnO:Fe NWs was carried out in the solution containing 25 mM of zinc nitrate (Zn(NO 3 ) 2 ), 12.5 mM of Hexamethylenetetramine (HMTA), and 0.25 mM of Iron (III) chloride (FeCl 3 ) at 95 • C. The process is similar to un-doped ZnO NWs growth [14], except for the addition of iron (III) to the growth solution. Figure 1 shows a schema of the Fe-doped ZnO nanowire formation.…”

“…The ZnO NWs (undoped and Fe-doped), synthesized by low-cost hydrothermal method with a high aspect ratio, offer a large surface to volume ratio. The detailed degradation mechanism has been proposed for each dye in our previous work [14].…”

Enhanced Photocatalytic Activity of ZnO Toward the Degradation of Methylene Blue Dye: Effects of Fe3+ and Sn4+ Doping

“…With the aid of ultraviolet (UV) light, the photogenerated electrons (e − ) and holes (h + ) in ZnO semiconductor can react with O 2 , OH − , and H 2 O to produce active species such as • O 2− and • OH. Organic pollutants in wastewater are eventually oxidized by these active species into small nontoxic organic compounds or inorganic substances such as H 2 O and CO 2 , thereby reducing pollution in the water environment.…”