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Structural, optical and photocatlytic properties of zinc oxide nanoparticles obtained by simple plant extract mediated synthesis
摘要： We report a facile and inexpensive method to prepare zinc oxide nanoparticles with different particle size and shape using Achyranthes aspera and Couroupita guianensis leaf extracts as the reducing agent and zinc nitrate as a precursor. The prepared zinc oxide nanoparticles were analyzed by various characterization methods and obtained results evidently revealed that crystalline parameter, purity, optical absorption, band gap, particle size and shape of the ZnO nanoparticles significantly influenced by the type of leaf extract used as reducing agent. Further, photocatlytic activity study obviously demonstrates that prepared samples exhibits superior photocatlytic activity for the degradation of methylene blue dye by creating superoxide anion radicals and OH radicals under photonic irradiation. Hence, prepared zinc oxide nanoparticles by plant extract mediated synthesis can be applied as a photocatlyst for the possible waste water treatment in textile industry.
关键词： Waste water treatment,Photocatalytic activity,Plant extract mediated synthesis,Methylene blue dye,Zinc oxide nanoparticles
更新于2025-09-23 15:21:21
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Blue LED light-driven photoelectrocatalytic removal of naproxen from water: Kinetics and primary by-products
摘要： Here, we demonstrate the viability of a ZnO/TiO2/Ag2Se thin-film composite synthesized on FTO to degrade the drug naproxen in aqueous solutions by visible-light photoelectrocatalysis (PEC). The experiments were made with 100 mL of solutions containing 5 mg L-1 drug and 50 mM Na2SO4 at natural pH, using a cell equipped with a Pt wire as cathode and the composite as photoanode exposed to a 36 W blue LED lamp. Total degradation was achieved after 210 min of electrolysis at anodic potential of +1.0 V/Ag|AgCl. This resulted from the oxidative action of hydroxyl radicals formed via direct anodic water discharge and through mediated water oxidation by photogenerated holes. The degradation rate decreased at higher naproxen concentration, but the treatment efficiency became higher due the deceleration of the parasitic reactions involving hydroxyl radicals. In chloride medium, the photoanode showed a large ability to produce active chlorine, which contributed to the oxidation of the target molecule. LC-QToF-MS analysis of treated solutions revealed the generation of four primary naphthalenic by-products, from which the initial degradation route of naproxen is proposed.
关键词： Photoelectrocatalysis,Water treatment,Oxidation by-products,Blue LED light,Pharmaceutical residue
更新于2025-09-23 15:21:01
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Multiwell plates for obtaining a rapid microbial dose-response curve in UV-LED systems
摘要： UV light-emitting diodes (UV-LEDs) have emerged as a new technology for water disinfection. Multiwell plates are a common tool in biological research, but they have never been used for UVC/UVB-inactivation experiments of microorganisms. In this study, a novel, rapid and simple UVC/UVB-inactivation assay was developed for a UV-LED system using a multiwell plate setup (96- and 24-well plates). The relative incident irradiance distribution across the exposed area was examined by spectroradiometry and nitrate-nitrite uniformity assay. The two methods showed a good correlation and high distribution factors (> 0.89 and > 0.94 for 96- and 24-well plates, respectively). In addition, the potential of the new system for determining disinfection efficacy of E. coli and MS2 coliphage by UV-LEDs emitting at central wavelengths of 265 nm and 285 nm was demonstrated. The inactivation rate constants were comparable to those obtained using UV-LED systems with the conventional dish (or beaker) setup, but the multiwell plate method allowed for many more repetitions. The proposed system is an alternative for UV-inactivation dose-response assay, especially when screening assays are desired, since it has the advantage of being fast, comprehensive (with a large number of simultaneous replicates) and easily adapted to various applications as UV-LED based photocatalysis experiments, UV effect on biofilm formation and UV-based AOP degradation experiments.
关键词： Water treatment,MS2 coliphage,UV light-emitting diode (UV-LED),E. coli,Multiwell plate
更新于2025-09-23 15:19:57
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Advanced Nanostructures for Environmental Health || Pilot-plant scaled water treatment technologies, standards for the removal of contaminants of emerging concern based on photocatalytic materials
摘要： The remediation of environmental problems is an actual concern in many kinds of approaches, including the quality of water and air, which are critical survival elements for us humans. To clean these important life necessities, suitable technologies are needed that could be applied very efficiently if there are standard procedures, limits, and approaches that we must apply. The definition of standardization is the following, according to Xie et al. [1]: “Standardization is the process of implementing and developing technical standards based on the consensus of different parties that include firms, users, interest groups, standards organizations, and governments.” The problem, in fact, lies in the existence of the term “interest groups,” which undermine the fast development of standardization procedures. Moreover, a research area such as photocatalysis is one of those that constantly changes, imposing significant pressure on standardization, including dynamic response. This is nearly impossible as photocatalysis is still showing increasing trends (Fig. 12.1).
关键词： standardization,Photocatalysis,contaminants of emerging concern,photocatalytic reactors,water treatment
更新于2025-09-23 15:19:57
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Carbon Nanomaterials for Agri-Food and Environmental Applications || Graphene quantum dot-based nanostructures for water treatment
摘要： Water pollution by organic, inorganic, and microbial species presents a threat to the water supply as well as food safety and security. Graphene quantum dot-derived nanostructures have emerged as potential solutions toward water pollution mitigation. Such materials have been successfully prepared and evaluated for the catalytic removal of organic pollutants such as dyes and emerging pollutants, the adsorption of pollutants, filtration, and disinfection. Incorporation of GQDs in various nanocomposites resulted in the modification of the composite properties and improved the removal efficiencies of different pollutants. Careful control and optimization of the amounts of GQDs incorporated are necessary to ensure a positive influence in the pollutant-removal efficiencies of the different nanocomposites. Despite the promising developments around GQD-based nanostructures, more work still remains in order to ensure the design and utilization of such materials in large-scale applications. Nonetheless, GQD-derived nanostructures have potential as pollution remediation tools, owing to the nontoxicity, biodegradable, and abundant functional groups. However, there is a need to develop optimized synthesis conditions that will yield GQDs that are uniform in terms of size and surface functionalities and also develop synthesis routes that will ensure proper distribution of the GQDs within the nanocomposite matrix. This could contribute to consistency in terms of the reported performances of various GQD-derived nanostructures in water pollution abatement.
关键词： membrane filtration,photocatalysis,Graphene quantum dots,water treatment,adsorption
更新于2025-09-23 15:19:57
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Morphological effect of titanate nanostructures on the photocatalytic degradation of crystal violet
摘要： The heterogeneous photocatalysis using semiconductor nanocrystals is an important process in the field of water treatment since it is a low cost, environmentally friendly, and zero waste technique. In this work, titanate nanostructures (sheets, tubes, and wires) were prepared by simple hydrothermal method. All samples were characterized by X-ray diffraction, transmission electron microscopy, Brunauer–Emmett–Teller surface area analysis, and Zetasizer. The results revealed that tuning the morphology of TiO2 changed the activity of the prepared nanostructures, where titanate nanowires exhibited the highest photocatalytic activity toward crystal violet dye, reaching 100% at pH 3 under ultraviolet illumination for 35 min.
关键词： water-treatment,crystal violet,selectivity,Selective degradation,titanate,photocatalysis
更新于2025-09-19 17:15:36
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Proof of Concept for Light Conducting Membrane Substrate for UV-Activated Photocatalysis as an Alternative to Chemical Cleaning
摘要： Adopting an effective strategy to control fouling is a necessary requirement for all membrane processes used in the water/wastewater treatment industry to operate sustainably. The use of ultraviolet (UV) activated photocatalysis has been shown to be effective in mitigating ceramic membrane fouling by natural organic matter. The widely used configuration in which light is directed through the polluted water to the membrane’s active layer suffers from inefficiencies brought about by light absorption by the pollutants and light shielding by the cake layer. To address these limitations, directing light through the substrate, instead of through polluted water, was studied. A UV conducting membrane was prepared by dip coating TiO2 onto a sintered glass substrate. The substrate could successfully conduct UV from a lamp source, unlike a typical alumina substrate. The prepared membrane was applied in the filtration of a humic acid solution as a model compound to study natural organic matter membrane fouling. Directing UV through the substrate showed only a 1 percentage point decline in the effectiveness of the cleaning method over two cleaning events from 72% to 71%, while directing UV over the photocatalytic layer had a 9 percentage point decline from 84% to 75%. Adapting the UV-through-substrate configuration could be more useful in maintaining membrane functionality during humic acid filtration than the current method being used.
关键词： photocatalytic membrane,membrane fouling,Titanium dioxide,water treatment
更新于2025-09-19 17:15:36
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Glucose Induced Formation of Oxygen Vacancy and Bi-Metal Co-modified Bi5O7Br Nanotubes for efficient Performance Photocatalysis
摘要： Here, we prepared Bi metal modified defective-Bi5O7Br nanotubes (Bi/Bi5O7Br-OV) by hydrothermal synthesis to be an efficient photocatalyst. The density function theory (DFT) revealed that oxygen vacancies in Bi5O7Br could form an intermediate level, which could allow electron transfer to new intermediate level, and finally move to the conduction band. The Bi/Bi5O7Br-OV nanotubes demonstrate superior photocatalytic degradation of phenol, showing 3 times higher than that of pristine Bi5O7Br. The defects and Bi endow Bi5O7Br nanotubes with abundant active sites and improve the solar absorption. The increased and more dispersed charge density allow enhanced electronic conductivity and the separation of photogenerated carriers. Furthermore, more ·OH radicals are generated during photochemical reaction, which is beneficial in improving the photocatalytic performance. This work will play significant roles and create opportunities in modifying Bi-based materials for promoting photocatalysis.
关键词： photodegradation,bismuth oxybromide,water treatment,visible light irradiation
更新于2025-09-19 17:15:36
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Laser-induced graphene and carbon nanotubes as conductive carbon-based materials in environmental technology
摘要： Nanotechnology and nanomaterials have attracted interest due to their potential in mitigating contemporary environmental challenges, such as the stressors imposed by increased industrial and agricultural activities, and the deterioration of air, soil and water quality. In particular, advanced technologies that harness carbon-based nanomaterials are poised to emerge as tools that provide new solutions for the global water crises. These tools include, electrically conductive membrane processes, which uniquely combine a separation process with a functional surface. In this respect, laser-induced graphene (LIG) and carbon nanotubes (CNTs) are electrically conductive carbon nanomaterials that hold great utility in a multitude of environmental applications, including the development of fouling-resistant systems for desalination and water treatment, enhanced separation methods, and innovative pollutant sensing and electrocatalytic platforms. Consequently, this review article describes and compares some important recent advances in LIG- and CNT-based electroactive surfaces. The discussion of LIG as an emerging carbon material set in context with CNTs is intended to shed light on future directions and development possibilities to meet the growing global challenges in terms of water treatment applications of both materials as well as other electrically conductive carbon-based nanomaterials exhibiting exceptional performance and versatility.
关键词： environmental applications,nanomaterials,electrically conductive membrane processes,laser-induced graphene,Nanotechnology,water treatment,carbon nanotubes,carbon-based nanomaterials
更新于2025-09-16 10:30:52
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Photocatalytic degradation using TiO2-graphene nanocomposite under UV-LED illumination: Optimization using response surface methodology
摘要： Poor efficiency of TiO2 by visible light and the fast recombination rate of electron/hole pairs remain significant challenges in photocatalytic applications of TiO2 in water treatment. In this study, graphene was used to enhance TiO2 photocatalytic activity by reducing electron-hole pair recombination. Nanocomposites were formed by combining TiO2 nanoparticles (P25) with graphene oxide (GO) though simultaneous hydrothermal synthesis and GO reduction. Nanocomposite characterization confirmed that the GO was successfully reduced and P25 nanoparticles evenly dispersed in the graphene surface. The band gap of the nanocomposite was determined to be 2.74 eV, which is a promising shift to the visible spectrum in graphene-TiO2 photocatalysts. The photocatalytic performance of the TiO2/G nanocomposites was then evaluated by quantifying the formation of 2-hydroxyterephthalic acid (HTPA) (probe molecule) under UV-LED illumination. To further optimize the photocatalytic efficiency of the TiO2/G nanocomposites, the response surface methodology (RSM) with central composite design (CCD) was used. Out of the 6 variables including stirring time, stirring speed, the amount of TiO2, the amount of GO, hydrothermal reaction time, and ethanol/water ratio, it was determined that the last three are substantially affected the HTPA formation rate. The optimum conditions were found to be GO 0.48 wt%, ethanol/water 51.49 v/V%, and a reaction time 19 h. Predicted values for HTPA formation were found to be in good agreement with experimental values (R2 = 0.93 and adj-R2 = 0.87). The optimized nanocomposite showed 125% enhancement in photocatalytic efficiency over pure P25.
关键词： P25-graphene nanocomposite,DOE,Photocatalysis,Water treatment,RSM
更新于2025-09-16 10:30:52