Synthesis, characterization and photocatalytic performance of W6+ impregnated g-C3N4 for the removal of chlorophenol derivatives in natural sunlight exposure
| Autor: | M. Aslam, Duna Abdul Kaream Alenazi, Sivaraman Chandrasekaran, Ekram Y. Danish, Iqbal M.I. Ismail, Abdul Hameed, Shahid Ali, M. Tahir Soomro |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Environmental Engineering
Health Toxicology and Mutagenesis 0208 environmental biotechnology Ion chromatography Oxide 02 engineering and technology 010501 environmental sciences 01 natural sciences Catalysis law.invention chemistry.chemical_compound X-ray photoelectron spectroscopy law Environmental Chemistry Calcination 0105 earth and related environmental sciences Chlorophenol Public Health Environmental and Occupational Health General Medicine General Chemistry Pollution 020801 environmental engineering Dielectric spectroscopy chemistry Photocatalysis Nuclear chemistry |
| Zdroj: | Chemosphere. 265:129135 |
| ISSN: | 0045-6535 |
| DOI: | 10.1016/j.chemosphere.2020.129135 |
| Popis: | The surface of the g-C3N4 was altered by impregnating W6+ ions that transformed to homogeneously coated oxide layer by a calcination process. An enhanced absorption and the suppressed de-excitation in the emission spectra, with the increasing W6+ loading, exposed the supporting role of the coated layer in extending the spectral response as well as the prolonged life span of excitons. The same was further supported by electrochemical impedance spectroscopy (EIS). The XRD and XPS analysis revealed the coated layer as highly crystalline pure phase monoclinic WO3 with the majority of impregnated tungsten ions in 6+ oxidation state respectively, whereas the FESEM and HRTEM analysis substantiated the uniformity of the coated layer with the interlayer spacing of the 0.369 nm. Additionally, the probable formation of individual WO3 nanoparticles or clusters was ruled out. The as-synthesized impregnated photocatalysts, in comparison to pure g-C3N4, were subjected to natural sunlight exposure for the photocatalytic removal of chlorophenol derivatives (2-CP, 3-CP, 4-CP, 2,3-DCP, 2,4-DCP, 2,4,6-TCP and PCP) that revealed the 5 wt% coating as the optimum level for significant removal. The progress of the photocatalytic process was monitored by periodic HPLC analysis whereas ion chromatography (IC) was used for the estimation of released ions. The mineralization capability of the as-synthesized W6+ coated catalysts was measured by the time scale TOC measurements. As the formation of intermediates was indicated in HPLC analysis, selected samples were subjected to GC-MS analysis for the identification of the nature of intermediates. The variable degree of removal of chlorophenol derivatives signified the role of the position and orientation of Cl group. The kinetics of the removal process was evaluated with the calculation of rate constants. The results extracted from the analytical tools and the associated band edge potentials were correlated to speculate the probable mechanism as well as the identification of major reactive oxygen species (ROS) involved in the removal process. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect