Fast Degradation of Green Pollutants Through Nanonets and Nanofibers of the Al-Doped Zinc Oxide

Abstract

In this study, series of nanolayered structures of Zn-Al LDHs were prepared by urea hydrolysis. Nanofibers and nanonets of the Al-doped ZnO were formed via the decomposition of the nanolayers under high pressure and temperature. Nanospheres were also prepared for comparison. The different morphologies of the prepared nanomaterials were confirmed by several techniques. An improvement for the optical properties of the doped zinc oxides was observed through narrowing of their band gap energies because of transforming the nanolayers to nanonets and nanofibers. The photocatalytic activities of the prepared nanomaterials were studied through photocatalytic degradation of the pollutants of acid green dyes. Complete decolorization and mineralization of green dyes happened in the presence of the nanolayers and nanospheres within 4-6 h, while the nanonets and the nanofibers achieved the complete decolorization and degradation of the dyes at shorter time 1.3 h. These results could be explained though the kinetic study of the photocatalytic degradation of dyes. It was concluded that the nanonets and the nanofibers were very effective for the photocatalytic degradation of pollutants.Keywords Al-doped ZnO nanolayers Á Nanofibers Á Nanonets Á Band gap energy Á Photocatalytic degradation Á Acid green dyes pollutants

Accelerating the Photocatalytic Degradation of Green Dye Pollutants by Using a New Coating Technique for Carbon Nanotubes with Nanolayered Structures and Nanocomposites

“…From Figure a, it could be inferred that the decolorization and degradation of dye under UV light with CNTs‐LDH as the photocatalyst exhibited pseudo‐first‐order behavior with a rate constant of 1.2 h −1 . Compared with recently reported conventional Zn‐Al LDHs (without CNTs), the rate constant for the photocatalytic degradation of green dye in the presence of CNTs‐LDHs was higher. Thus, the coating of CNTs with LDHs accelerates the photocatalytic degradation.…”

“…To confirm the effect of coating CNTsw ith LDH nanoplatelets or aluminum zinc oxide nanocomposite, the kinetics of the photocatalytic decolorization and degradation of green dye were studied for CNTs-LDH and nanocomposite-coated CNTs. The kinetics of the decolorization and degradationo ft he dye can be represented by Equation (2): From Figure 12a, it could be inferred that the decolorization and degradation of dye under UV light with CNTs-LDH as the photocatalyst exhibited pseudo-first-order behavior with ar ate constant of 1.2 h À1 .C ompared with recently reported conventional Zn-Al LDHs (without CNTs), [3] the rate constant for the photocatalytic degradation of green dye in the presence of CNTs-LDHs was higher.Thus, the coating of CNTswith LDHs accelerates the photocatalytic degradation.W ith aluminumz inc oxide nanocomposite-coatedC NTst he rate constant was 4.1 h À1 ,w hich is five times highert han Al-dopedz inc oxide nanoparticles, as previously published by our laboratory, [5] for the decolorization and photodegradation of green dye.…”

“…Therefore, the absorption data, which matches the electronic excitation from the V B to the C B , could be used to calculate the energy bandgap ( E g ). The relationship between the absorption coefficient (Abs) and the incident photon energy ( E = hν ) is defined in Equation : …”

“…It is known that even low concentrations of dyes can cause health problems in humans and animals. Consequently, in recent decades the elimination of synthetic dyes has become a global problem because of these colorful effluents . This topic has attracted our attention because it is aimed at accelerating the decomposition of pollutants and also at the discovery of new techniques for coating CNTs with dual metal oxide nanocomposites.…”

Designing Magnetic Layered Double Hydroxides and Two-Dimensional Magnetic Nano-Nets of Cobalt Ferrite through a Novel Approach

“…Development of zero-, one-, and two-dimensional nanostructures has been a very interesting field for research because of the unique and amazing properties of the nanomaterials [1][2][3]. Therefore, the nanoparticles and the nanofibers have unlimited uses in various fields [4][5][6].…”