Exploring the impact of cold plasma-induced surface oxygen vacancies on charge carrier dynamics in Z-scheme CoMoO6/ZrO2/GO heterojunction for efficiency improvement in photocatalysis
Mahwish Iqbal , Muhammad Ahsan Rashid , Rida Fatima , Mahreen Iqbal , Haq Nawaz Bhatti
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引用次数: 0
Abstract
Oxygen vacancies (OVs) in semiconductors play a critical role in enhancing the efficiency of photocatalysis. We have demonstrated the fabrication of a novel cobalt-molybdate heterojunction with zirconia and graphene oxide as a supported-electron-mediator (CoMoO6/ZrO2/GO; CMZG) via hydrothermal approach and creation of surface OVs in the said composite through microwave cold plasma post-treatment. The applications of treated composite (MCPT-CMZG) were elucidated for photodegradation of BBY and BF dyes, industrial wastewater, and catalytic inactivation of E. coli and S. aureus. The fabricated composites were analyzed through XRD, SEM-EDX, FTIR, UV–Vis spectroscopy, DLS, and EPR. The results showed that MCPT-CMZG revealed mixed tetragonal ZrO2 and monoclinic CoMoO6 phases, porous morphology, band gap of 2.29 eV, z-average of 201 ± 5 nm, and zeta potential of −36.34 ± 5 mV. Photoactivity of MCPT-CMZG was investigated under sunlight and remarkable degradation efficiencies of 96 and 99.3 % were achieved under pH = 5 and 6, catalyst dose = 40 and 30 mg/L, dye dose and irradiation time = 10 mg/L/40 min for BBY and BF, respectively. Successful degradation of dyes to environmentally-friendly compounds was confirmed by FTIR, H-ESI-MS/MS, and TOC analyses. According to kinetic studies, pseudo-first-order model was best-fitted on the experimental data. Antibacterial activity of MCPT-CMZG and toxicity studies of photodegraded dye media against pathogenic strains exhibited higher inhibition zone (13 mm) and greater cell viability (BBY = 93.72 %; BF = 94.63 %) against E. coli, respectively. Moreover, during prolonged UV and visible-light exposure tests, 1–3 % decline in catalytic efficiency and 76.34 % reduction in COD of industrial wastewater using MCPT-CMZG, highlighting its potential for practical applications, especially in pollutant removal.
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The Journal of Water Process Engineering aims to publish refereed, high-quality research papers with significant novelty and impact in all areas of the engineering of water and wastewater processing . Papers on advanced and novel treatment processes and technologies are particularly welcome. The Journal considers papers in areas such as nanotechnology and biotechnology applications in water, novel oxidation and separation processes, membrane processes (except those for desalination) , catalytic processes for the removal of water contaminants, sustainable processes, water reuse and recycling, water use and wastewater minimization, integrated/hybrid technology, process modeling of water treatment and novel treatment processes. Submissions on the subject of adsorbents, including standard measurements of adsorption kinetics and equilibrium will only be considered if there is a genuine case for novelty and contribution, for example highly novel, sustainable adsorbents and their use: papers on activated carbon-type materials derived from natural matter, or surfactant-modified clays and related minerals, would not fulfil this criterion. The Journal particularly welcomes contributions involving environmentally, economically and socially sustainable technology for water treatment, including those which are energy-efficient, with minimal or no chemical consumption, and capable of water recycling and reuse that minimizes the direct disposal of wastewater to the aquatic environment. Papers that describe novel ideas for solving issues related to water quality and availability are also welcome, as are those that show the transfer of techniques from other disciplines. The Journal will consider papers dealing with processes for various water matrices including drinking water (except desalination), domestic, urban and industrial wastewaters, in addition to their residues. It is expected that the journal will be of particular relevance to chemical and process engineers working in the field. The Journal welcomes Full Text papers, Short Communications, State-of-the-Art Reviews and Letters to Editors and Case Studies
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