Wastewater Disinfection Research Articles

Facile fabrication and characterization of carboxymethyl cellulose loaded with TiO2NPs hydrogel as a promising disinfectant for eliminating the dissemination of waterborne pathogens through wastewater decontamination

The purpose of this work was to develop and characterize an intriguing hydrogel called TiO₂NPs@CMC hydrogel, which is composed of carboxymethyl cellulose (CMC) and loaded with titanium oxide nanoparticles (TiO₂NPs) for effective waterborne pathogen disinfection in wastewater. The TiO₂NPs were synthesized through hydrolysis and peptization, incorporated into a CMC matrix, and subsequently cross-linked with calcium chloride (CaCl₂). Characterization through TEM, FTIR, and SEM validated the development of a porous structure, efficient incorporation of TiO₂NP, and successful crosslinking. In this study, TiO2NPs were prepared and affirmed the significant particle distribution with a small size using TEM. The TiO₂NPs@CMC hydrogel exhibited significant antimicrobial and antibiofilm properties against various pathogens, such as Salmonella typhi, E. coli O157, Shigella dysenteriae, Enterococcus faecalis, Bacillus cereus, and Candida albicans, with highest inhibition zone diameters of up to 29 mm for S. typhi. The inhibitory effect demonstrated that the hydrogel significantly decreased bacterial populations at 100 μg/mL concentrations. The hydrogel demonstrated a 2.7-log reduction in microbial counts in sewage water within 120 min, achieving complete inactivation of pathogens at a concentration of 2xMIC within 180 min. The biofilm inhibition rate reached 87.6 % against B. cereus. Toxicity assessments demonstrated significant biocompatibility, with no negative effects noted in environmental applications. The findings indicate that TiO₂NPs@CMC hydrogel is a viable option for sustainable wastewater treatment, providing an efficient, safe, and environmentally friendly method for the removal of waterborne pathogens and the prevention of biofilm formation.

Synergistic Effects of Polydopamine/Medical Stone Bio-Adsorbents for Enhanced Interfacial Adsorption and Dynamic Filtration of Bacteria.

Polymer-based wastewater disinfection, which is typically performed using chemical oxidation or irradiation, can result in various toxic byproducts and corrosion under harsh environments. This study introduces a robust bio-adsorbent prepared from naturally abundant polydopamine-modified medical stone (MS@PDA) for the high-efficiency removal of bacteria from water. The PDA nanocoating can be easily applied through an in situ self-polymerization process, resulting in a considerably high bacterial adsorption capacity of 6.6 k pcs mm-2 for Staphylococcus aureus. A cyclic flow-through dynamic filtration and a disinfection system was implemented using an MS@PDA porous filter with an average pore size of 21.8 ± 1.4 µm and porosity of ~83%, achieving a 5.2-6.0-fold enhancement in the cumulative removal efficiency for MS@PDA2. The underlying mechanisms were elucidated through the synergistic effects of interfacial bio-adsorption and size-dependent interception. Notably, the bacteria captured on the surface could be killed using the enhanced photothermal effects of the PDA nanocoating and the inherent antimicrobial properties of the mineral stone. Thus, this study not only provides a new type of advanced bio-adsorbent but also provides new perspectives on an efficient and cost-effective approach for sustainable wastewater treatment.

Investigating the catalytic and antibacterial behavior of cesium-doped MoO3 nanostructures against methylene blue dye and MDR E. coli with DFT analysis

Water pollution, exacerbated by inadequate water management practices, has compromised the effectiveness of traditional water treatment technologies. The integration of metal oxide-based nanomaterials in treatment systems has the potential to revolutionize the field of wastewater treatment, providing a sustainable and efficient solution to the growing global water crisis. This study focused on the fabrication of hexagonal cesium (Cs) doped MoO3 nanostructures (NSs) for their potential use as catalytic and antibacterial agents. Various structural, optical, and morphological analysis was conducted to examine these NSs. The UV–Vis spectroscopy results showed that as Cs concentration increased, the band gap energies of MoO3 decreased from 3.5 eV to 3.0 eV. The field emission scanning electron microscopy (FESEM) investigation revealed the plate-like structural morphology of MoO3 formed by overlapping one layer onto another. Cs doping effectively inhibited the recombination of photo-generated charge carriers, resulting in a significant reduction in PL peak intensity for Cs-doped MoO3 compared to MoO3. The prepared NS-reduced methylene blue dye in the absence of light under different pH conditions, reaching 86.8% with 2% Cs-doped MoO3. Density functional theory (DFT), utilizing the Heyd-Scuseria-Ernzerhof hybrid (HSE06) method, was employed to model and compute the interactions between methylene blue (MB) and Cs-doped MoO3 during MB adsorption. Bactericidal experiments on multidrug-resistant Escherichia coli showed that the NSs had remarkable antibacterial action, generating an inhibition zone of 9.15 mm at higher doses using 6% Cs-doped MoO3. Consequently, these findings offer potential significance for research in developing and implementing wastewater disinfection systems.

Efficiency and mechanistic insights of photocatalytic degradation and sterilization utilizing g-C3N4/WO3-x Z-scheme heterojunction under full-spectrum light

Designing highly efficient full-spectrum responsive Z-scheme heterojunction for wastewater decontamination and disinfection is urgently essential. Herein, a novel Z-scheme g-C3N4/WO3-x heterojunction was successfully synthesized by a facile wet impregnation method for the highly efficient photocatalytic degradation and sterilization. Benefiting from the accelerated charge separation, broadened light absorption to near infrared region, and appropriate band energy, optimized g-C3N4/WO3-x heterojunction exhibited photocatalytic degradation of 86.3 % and 97.4 % tetracycline in 2 h under visible light and full-spectrum light, respectively. Meanwhile, 6.5-log of Escherichia coli strains could also be inactivated by optimized g-C3N4/WO3-x heterojunction within 45 min and 15 min under visible light and full-spectrum light, respectively. Impressively, it also exhibited desirable anti-interference ability and satisfying photocatalytic degradation capacity with various key experimental parameters. The plausible degradation pathways of TC and the main active species involved in the photocatalysis were investigated based on liquid chromatography-mass spectrometer (LC-MS) and electron paramagnetic resonance (EPR) analysis. Mineralization process of TC was further confirmed by three-dimensional fluorescence spectra (3D EMMs). Besides, Toxicity Estimation Software Tool (T.E.S.T.) and Ecological Structure-Activity Relationships (ECOSAR) program were applied to predict the noxiousness of TC and its potential intermediates. The results suggested that the excitotoxicity of intermediates generally decreased relative to the pristine TC. Finally, we propose a plausible enhancement mechanism of photocatalytic degradation and sterilization. This work sheds a new light on the design of novel full-spectrum responsive Z-scheme heterojunction for environmental remediation.

Study of ilmenite and zero valent iron nanoparticles for persulfate activation in disinfection of wastewater

This study examines the activation of persulfate (PS) using two different iron sources, namely ilmenite (ILM) and zero valent iron nanoparticles (ZVI), under UV-A radiation, to eliminate Enterococcus sp. in simulated wastewater in a recirculating batch reactor. The best combination of PS/ILM/UV-A was found with a PS concentration of 5 mM and an ILM concentration of 5 g/L, resulting in a 2.76- log reduction of Enterococcus sp. after 120 min. Lower dosages of oxidant and catalyst were required in the PS/ZVI/UV-A system (3 mM PS and 0.1 g/L ZVI), achieving the complete inactivation of Enterococcus sp. in 60 min. ZVI was more effective at inactivating Enterococcus sp. colonies than ILM. Additionally, the treatment performed better at neutral pH than in acidic or basic conditions, which could facilitate applications on a larger scale. Furthermore, ZVI could be recovered with minimal loss of efficacy thanks to its magnetic properties. The mechanistic study indicated that SO4•- radicals are the primary radicals involved in the elimination of Enterococcus sp. through PS activation. Phytotoxicity studies showed that the process is not phytotoxic to Solanum lycopersicum (tomato) germination but is to Raphanus sativus (radish).

Introducing a Promising New Disinfection Technology for the Fonce River in Colombia

Urban wastewater disinfection is a critical component of environmental sustainability and human health. Current technologies for this are often costly and inaccessible to many communities. Typically, this treatment is carried out by chemical processes, with chlorination being the most common despite the potential for harmful disinfection byproducts. However, the emergence of promising alternatives, such as physical processes that utilize hydrodynamic cavitation reactors (HCRs), offers significant energy and environmental benefits. Based on this, the Fundación Universitaria San Gil, UNISANGIL, has developed a technology that utilizes hydrodynamic cavitation (HC) to disinfect urban wastewater samples discharged into the Fonce river in San Gil, Santander, Colombia. The primary objective of this research was to test the ability of a hydrodynamic cavitation system to reduce total coliforms and fecal coliforms (E. coli) in a 200 L tank containing 12.5 L of domestic urban wastewater diluted in 187.5 L of non-residual water. The methodology consisted of three steps: HCR design and simulation, HC implementation, and disinfection measurement. The experiments were conducted with a Venturi-type HCR, designed with computational fluid dynamics, and tested with wastewater samples from one of the ten discharges that flow into the river. The results obtained for a system with a flow capacity of 0.00625 m3/s show an average growth inhibition rate of 31.72 %, 59.45 %, and 84.53 % for one, ten, and twenty water recirculation, respectively, with an energy efficiency of 2327.6 CFU/J. The highest results reach a Growth Inhibition Rate (GIR) of 93.40 %, a Logarithmic Reduction (LR) of 1.18 for Total Coliforms, and a GIR of 95.12 % and an LR of 1.31 for E. coli. Finally, it is concluded that this technology holds great promise for efficiency and operational viability, with further testing required to realize its potential.

Development of nanocomposite-selenium filter for water disinfection and bioremediation of wastewater from Hg and AgNPs

Selenium nanoparticles (SeNPs) are used in several sectors as antitumor, antimicrobial, and environmental adsorbents. Thus, the present research objective was the production of bacterial-SeNPs as an active and environmentally-friendly antibacterial and adsorbent agents and application into novel nanocomposite filter. From a total of 25 samples (soil, wastewater, and water) obtained from different locations in Egypt, 60 selenium-resistant bacterial isolates were obtained (on a mineral salt medium supplemented with selenium ions). After screening (based on the conversion of selenium from ionic form to nanoform), a superior bacterial isolate for SeNPs formation was obtained and molecular identified as Bacillus pumilus isolate OR431753. The high yield of SeNPs was noted after optimization (glucose as carbon source, pH 9 at 30 °C). The produced SeNPs were characterized as approximately 15 nm-diameter spherical nanoparticles, in addition to the presence of organic substances around these particles like polysaccharides and aromatic amines (protein residues). Also, they have antibacterial activity increased after formation of nanocomposite with nano-chitosan (SeNPs/NCh) against several pathogens. The antibacterial activity (expressed as a diameter of the inhibitory zone) averaged between 2.1 and 4.3, 2.7 and 4.8 cm for SeNPs and SeNPs/NCh, respectively compared with 1.1 to 1.8 cm for Amoxicillin. The produced nanoselenium/chitosan was used as a biofilter to remove mercury (Hg) and AgNPs as model chemicals with serious toxicity and potential pollutant for water bodies in many industries. The new SeNPs/NCh biofilter has proven highly effective in individually removing mercury and AgNPs from their synthetic wastewaters, with an efficiency of up to 99%. Moreover, the removal efficiency of AgNPs stabilized at 99% after treating them with the syringe filter-Se nanocomposite for 4 cycles of treatment (5 min each).

Green synthesis of Z-scheme N-doped g-C3N4/Nd-doped ZnO heterostructure by pomegranate waste peel with enhanced photocatalytic performance for organic pollutants removal and antibacterial activity

Nowadays, the growing global population and increased industrialization have exacerbated water pollution, posing a significant environmental threat. To tackle this issue, there is an urgent need for effective catalysts to remove pollutants. This study developed a novel N-doped g-C3N4/Nd-doped ZnO (NZ) heterostructure using a green approach by incorporating pomegranate peel waste as a stabilizing and capping agent. Characterization techniques confirmed successful NZ nanohybrid preparation. The synthesized NZ displayed high photocatalytic activity in degrading methylene blue (MB) and tetracycline (TC) pollutants found in wastewater, achieving degradation efficiencies of 95.3 % and 98.3 %, respectively. Meanwhile, it demonstrated satisfactory photostability after five-cycle experiments. The radical trapping experiments revealed that superoxide (O2−) and hydroxyl (OH) are the dominant active species and play an essential role in photocatalytic pollutant deterioration. Additionally, it exhibited suitable antimicrobial activity against Staphylococcus aureus and Vibrio cholerae bacterial strains. The enhanced performance is attributed to the abundant reaction sites of porous N-doped g-C3N4, the photo-redox capability of Nd-doped ZnO, and the efficient charge separation process in the Z-type heterojunction. This work advances sustainable and eco-friendly chemistry for the biosynthesis of organic/inorganic heterojunctions used in pollutant degradation and bacterial disinfection of wastewater.

Enhanced photocatalysis by defect-engineered CeO2 with sulfite activation under visible light irradiation

Sulfite-based advanced oxidation processes (s-AOPs) have recently garnered significant attention due to their ability to generate highly oxidative sulfate radicals and eliminate contaminants from water. A state-of-the-art platform has been developed through the synergistic combination of s-AOP and photocatalysis under visible light as weak as ambient indoor daylight. This platform achieved an enhanced degradation efficiency for defect-engineered CeO2 nanocubes by using sodium sulfite instead of SO2, resulting in a synergy factor of up to 88%. The reaction pathways, intermediates, ion leaching and the possible influence of aqueous conditions during the methyl orange degradation have been investigated. The CeO2/Na2SO3/vis-light platform exhibits promising prospect as a system to enhance conventional s-AOP in wastewater treatment or disinfection. It demonstrates excellent performance in terms of pH sensitivity, anion influence, and resistance to leaching. This highlights its significant potential for practical applications and future process scale-up.

Solar-driven environmental fate of chlorinated parabens in natural and engineered water systems

Parabens are classified as emerging contaminants in global waters, and the ubiquitous emergence of their high-risk chlorinated products generated from chlorine-based wastewater disinfection has attracted increasing attention. However, rather limited information is available on their photofate after discharging into surface waters, and their degradation behavior after solar-based engineering water treatment is unclear. Herein, the reactivity of four chlorinated parabens with different photochemically produced reactive intermediates was measured. Quantitative contribution analysis in abating such compounds showed the dominance of direct photolysis in sunlit natural freshwaters. Introducing a technical solar/peroxymonosulfate (PMS) system could greatly improve the removal of chlorinated parabens. The economic analysis suggested that chlorinated parabens exhibited a minimum value of economic input as 93.41–158.04 kWh m-3 order-1 at 0.543–0.950 mM PMS. The high-resolution mass spectrometry analysis of the degradation products suggested that dechlorination, hydroxylation, and ester chain cleavage were the dominant transformation pathways during photolysis and solar/PMS treatment. Furthermore, the in silico prediction indicated severe aquatic toxicity of certain products but enhanced biodegradability. Overall, this investigation filled a knowledge gap on the reactivity of chlorinated parabens with diverse reactive transients and their quantitative contributions to the photolysis and solar/PMS treatment of emerging micropollutants in water.

Removal of Escherichia coli and Enterococcus faecalis from synthetic wastewater using thermally treated palygorskite as a bacterial adsorbent in fixed bed reactors

AbstractBACKGROUNDIn pursuit of innovative wastewater treatment solutions, this study investigates the use of thermally treated palygorskite (TP) as an adsorbent to remove Escherichia coli and Enterococcus faecalis from synthetic wastewater. The goal is to explore a natural alternative to chlorine‐based disinfectants by utilizing TP's antimicrobial properties. Columns were packed with two granulometries (G1: 0.25–0.6 mm; G2: 1.40–2.36 mm) of TP and arranged in three different configurations (CA1, CA2 and CA3) to assess their bacterial removal efficiency, kinetic behavior and potential for reuse after dry heat sterilization.RESULTSThe CA3 column configuration, with its multilayer arrangement of TP, achieved the highest bacterial removal efficiency, reaching 99.1% for E. coli and 98.1% for E. faecalis. Kinetic experiments revealed that most bacterial adsorption occurred within the first 3 min, with E. coli requiring up to 10 min to reach maximum removal. TP's antibacterial effectiveness remained above 90% after two reuses. Additionally, dry heat sterilization allowed for repeated use of TP, showing stable removal efficiencies for E. faecalis and a slight decline for E. coli with each successive reuse.CONCLUSIONSTP demonstrates significant potential as an adsorbent for wastewater disinfection, particularly in the CA3 multilayer configuration. Its rapid adsorption kinetics and resilience to heat sterilization underscore its reusability, making it a viable natural alternative to chemical disinfectants. Further research should focus on scaling this method to real wastewater treatment applications to validate its functionality in real‐world conditions. © 2024 Society of Chemical Industry (SCI).

Effect of liquid surface depression size on discharge characteristics and chemical distribution in the plasma-liquid anode system

Atmospheric pressure plasma-liquid interactions exist in a variety of applications, including wastewater treatment, wound sterilization, and disinfection. In practice, the phenomenon of liquid surface depression will inevitably appear. The applied gas will cause a depression on the liquid surface, which will undoubtedly affect the plasma generation and further affect the application performance. However, the effect of liquid surface deformation on the plasma is still unclear. In this work, numerical models are developed to reveal the mechanism of liquid surface depressions affecting plasma discharge characteristics and the consequential distribution of plasma species, and further study the influence of liquid surface depressions of different sizes generated by different helium flow rates on the plasma. Results show that the liquid surface deformation changes the initial spatial electric field, resulting in the rearrangement of electrons on the liquid surface. The charges deposited on the liquid surface further increase the degree of distortion of the electric field. Moreover, the electric field and electron distribution affected by the liquid surface depression significantly influence the generation and distribution of active species, which determines the practical effectiveness of the relevant applications. This work explores the phenomenon of liquid surface depression, which has been neglected in previous related work, and contributes to further understanding of plasma-liquid interactions, providing better theoretical guidance for related applications and technologies.

Urban wastewater disinfection by FeCl3-activated biochar/peroxymonosulfate system: Escherichia coli inactivation and microplastics interference

Biochar coupled with peroxymonosulfate (PMS) to produce sulfate radicals and its application to urban wastewater disinfection has been rarely investigated and no information is available about microplastics (MPs) interference on the disinfection process. In this study, FeCl3-activated biochar (Fe-BC) was coupled to PMS to evaluate the inactivation of Escherichia coli (E. coli) in real secondary treated urban wastewater. Surface morphology of Fe-BC sample, characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), showed a rough texture with uniform distribution of iron particles over the entire surface area. E. coli inactivation improved (∼3.8 log units, detection limit = 1 CFU/100 mL) as Fe-BC concentration was decreased (from 1.0 g/L to 0.5 g/L), at a constant PMS dose (300 mg/L). Besides, removal efficiency of E. coli was negatively affected by the presence of small (30–50 μm) polyethylene MPs (PE MPs) (200 mg/L), which could be attributed to the adsorption of MPs on Fe-BC surface, according to SEM images of post-treated Fe-BC. The low disinfection efficiency of Fe-BC/PMS system in presence MPs could be due to blocking of Fe-BC sites for PMS activation and/or radicals scavenging during treatment. These results allowed to unveil the mechanisms of MPs interference on E. coli inactivation by Fe-BC/PMS, as well as the potential of this process to make the effluent in compliance with the stringent limit for agricultural reuse.

Radiolysis performance of ibuprofen using ionizing processes: kinetics and energy consumption

ABSTRACT Ionizing technologies are used for disinfection and treatment of different industrial wastewaters. For this purpose, the radiolytic degradation of ibuprofen (IBP), selected within the main detected pharmaceuticals in different water locations with different concentrations, was investigated. Irradiation was performed with a gamma irradiator (60Co) and with electron beam accelerator. The degree of ibuprofen degradation was monitored following the evolution of its absorbance, the residual concentration by HPLC, carbon oxygen demand and total organic carbon. The degradation of IBP was higher than the removal of TOC or COD and reached 95% according to residual concentration. This pollutant (at 0.1 mM) was totally degraded when irradiated at 3 kGy and needed higher doses (7–10 kGy) for the highest concentrations (0.8–1 mM). The addition of 1 mM of persulfate ion remarkably enhanced IBP degradation by around 2 and 2.8 times for 5 and 10 kGy, respectively. Pseudo-first-order reaction kinetics could be used to depict the degradation process of IBP in all conditions. Electrical energy per order (EEO) was estimated under various conditions. The smallest EEO was obtained when gamma radiation and persulfate ion were combined. The possible degradation pathways of IBP were proposed. The results achieved in this study can be used to optimize large-scale application of nuclear techniques in water treatment in particular in treating pharmaceutical effluents.

Native Microalgae-Bacteria Consortia: A Sustainable Approach for Effective Urban Wastewater Bioremediation and Disinfection.

Urban wastewater is a significant by-product of human activities. Conventional urban wastewater treatment plants have limitations in their treatment, mainly concerning the low removal efficiency of conventional and emerging contaminants. Discharged wastewater also contains harmful microorganisms, posing risks to public health, especially by spreading antibiotic-resistant bacteria and genes. Therefore, this study assesses the potential of a native microalgae-bacteria system (MBS) for urban wastewater bioremediation and disinfection, targeting NH4+-N and PO43--P removal, coliform reduction, and antibiotic resistance gene mitigation. The MBS showed promising results, including a high specific growth rate (0.651 ± 0.155 d-1) and a significant average removal rate of NH4+-N and PO43--P (9.05 ± 1.24 mg L-1 d-1 and 0.79 ± 0.06 mg L-1 d-1, respectively). Microalgae-induced pH increase rapidly reduces coliforms (r > 0.9), including Escherichia coli, within 3 to 6 days. Notably, the prevalence of intI1 and the antibiotic resistance genes sul1 and blaTEM are significantly diminished, presenting the MBS as a sustainable approach for tertiary wastewater treatment to combat eutrophication and reduce waterborne disease risks and antibiotic resistance spread.

Исследование дезинфицирующей способности феррата натрия

More and more attention has been recently paid to the disinfection of industrial wastewater. Food, petrochemical, pharmaceutical, and other industries cannot directly dump wastewater into the environment, therefore, the wastewater is fed to the deep biological treatment lines. A high level of biological threat and the expanding list of potential pathogens cause the need to search for new highly efficient disinfecting agents. The use of ferrates can be a new step in the improvement of the wastewater disinfection process due to the combination of processes of inactivation of pathogenic microflora and the reactant coagulation on ferric hydroxides generated during decontamination (oxidation). Within the framework of the study, the potential use of sodium ferrate as a disinfecting agent obtained by electrochemical dissolution of iron electrodes in alkali solutions has been confirmed. It has been established that sodium ferrate can effectively inactivate conditionally pathogenic cultures A. niger, B. subtillis which are part of activated sludge symbiosis. The efficient dosing of ferrate for complete inhibition of B. subtillis is 0.5 % mass, whereas for A. Niger it is 15 % mass. It has been proved that microflora inhibition occurs directly under the action of sodium ferrate and not due to the alkali reaction of the medium. Industrial tests of the disinfecting ability of ferrates in relation to wasted activated sludge of industrial wastewater deep biological treatment systems have confirmed the results obtained for individual objects (A. niger, B. subtillis). Based on the results, a conclusion about the potential use of ferrates in the deep biological treatment processes for highly bacteriologically contaminated industrial wastewater has been made. The main advantages of the suggested agent include the low toxicity of metabolites, minimum secondary contamination of treated water, and possible reactant advanced treatment (dephosphorization).

Phyco-biosynthesis of Chlorella-CuO-NPs and its Immobilization on Polyester/Cotton Blended Textile Waste Activated by Cellulase Enzymes for Application as Wastewater Disinfection Filter

Phyco-biosynthesis of Chlorella-CuO-NPs and its Immobilization on Polyester/Cotton Blended Textile Waste Activated by Cellulase Enzymes for Application as Wastewater Disinfection Filter

Relationship between chlorine decay and nanobubble application in secondary treated wastewater.

There has been numerous research on the uses of treated wastewater that needs chlorine disinfection, but none have looked at the impacts of injecting nanobubbles (NBs) on the decomposition of residual chlorine. Gas NB injection in treated wastewater improves its properties. The kinetics of disinfectant decay could be impacted by changes in treated wastewater properties. This paper studies the effect of various NB injections on the residual chlorine decay of secondary treated wastewater (STWW). It also outlines the empirical equations that were developed to represent these impacts. The results show that each type of NBs in treated wastewater had a distinct initial chlorine concentration. The outcomes demonstrated a clear impact on the decrease of the needed chlorine quantity and the reduction of chlorine decay rate when utilizing NB injection for the STWW. As a result, the residual chlorine will remain for a longer time and will resist any microbiological growth under the application of NBs on treated wastewater. Moreover, NBs in secondary treated effluent reduce chlorine usage, lowering wastewater disinfection costs.

Sustainable fabrication of dimorphic plant derived ZnO nanoparticles and exploration of their biomedical and environmental potentialities

Although, different plant species were utilized for the fabrication of polymorphic, hexagonal, spherical, and nanoflower ZnO NPs with various diameters, few studies succeeded in synthesizing small diameter ZnO nanorods from plant extract at ambient temperature. This work sought to pioneer the ZnO NPs fabrication from the aqueous extract of a Mediterranean salt marsh plant species Limoniastrum monopetalum (L.) Boiss. and assess the role of temperature in the fabrication process. Various techniques have been used to evaluate the quality and physicochemical characteristics of ZnO NPs. Ultraviolet–visible spectroscopy (UV–VIS) was used as the primary test for formation confirmation. TEM analysis confirmed the formation of two different shapes of ZnO NPs, nano-rods and near hexagonal NPs at varying reaction temperatures. The nano-rods were about 25.3 and 297.9 nm in diameter and in length, respectively while hexagonal NPs were about 29.3 nm. The UV–VIS absorption spectra of the two forms of ZnO NPs produced were 370 and 365 nm for nano-rods and hexagonal NPs, respectively. FT-IR analysis showed Zn–O stretching at 642 cm−1 and XRD confirmed the crystalline structure of the produced ZnO NPs. Thermogravimetric analysis; TGA was also used to confirm the thermal stability of ZnO NPs. The anti-tumor activities of the two prepared ZnO NPs forms were investigated by the MTT assay, which revealed an effective dose-dependent cytotoxic effect on A-431 cell lines. Both forms displayed considerable antioxidant potential, particularly the rod-shaped ZnO NPs, with an IC50 of 148.43 µg mL−1. The rod-shaped ZnO NPs were superior candidates for destroying skin cancer, with IC50 of 93.88 ± 1 µg mL−1 ZnO NPs. Thus, rod-shaped ZnO NPs are promising, highly biocompatible candidate for biological and biomedical applications. Furthermore, both shapes of phyto-synthesized NPs demonstrated effective antimicrobial activity against various pathogens. The outcomes highlight the potential of phyto-synthesized ZnO NPs as an eco-friendly alternative for water and wastewater disinfection.

Treatment and Disinfection of Municipal Wastewater Using Synergy of Ultrasound, LEDs-UVC, and Oxidants

Treatment and Disinfection of Municipal Wastewater Using Synergy of Ultrasound, LEDs-UVC, and Oxidants