Photocatalytic Degradation of Antibiotics by Superparamagnetic Iron Oxide Nanoparticles. Tetracycline Case

Influence of goethite on the fate of antibiotic (tetracycline) in the aqueous environment: Effect of cationic and anionic surfactants

Over the last decades, the release and occurrence of organic pollutants in aquatic systems have become a major global concern due to their bioaccumulation, toxicity, and adverse effects on the ecosystem. Tetracycline (TC), a widely used antibiotic, is often found at high concentrations in the aqueous environment and tends to bind with the natural colloids. Post-COVID-19 pandemic, the release of surfactants in the environment has increased due to the excessive use of washing and cleaning products. This study systematically investigated the interaction of goethite with TC in the absence and presence of anionic (sodium dodecyl sulfate, SDS) and cationic (cetyltrimethylammonium bromide, CTAB) surfactants. The impact of various environmental parameters like pH, ionic strength, temperature, and organic matter was also studied. It was observed that SDS has drastically increased TC sorption onto goethite from 11 mg/g to 19 mg/g, while CTAB had the opposite effect. To delineate the goethite-TC interaction mechanisms, FTIR with two-dimensional correlation analysis (2D-COS) was performed. The pH of the solution was crucial in the presence of SDS, while ionic strength did not affect the interaction process. The sorption process was endothermic, as evidenced by the increase in sorption capacity with the rise in the temperature. The presence of organic matter hinders the sorption of TC onto goethite, which is also observed in river water where the organic content is very high. Overall, our study helps to predict the fate of organic pollutants like antibiotics in aqueous environments in the coexistence of surfactants and iron oxyhydroxides.

The Photocatalytic Degradation of Enrofloxacin Using an Ecofriendly Natural Iron Mineral: The Relationship Between the Degradation Routes, Generated Byproducts, and Antimicrobial Activity of Treated Solutions

The use of ecofriendly natural minerals in photocatalytic processes to deal with the antimicrobial activity (AA) associated with antibiotics in aqueous systems is still incipient. Therefore, in this work, the capacity of a natural iron material (NIM) in photo-treatments, generating reactive species, to remove the antibiotic enrofloxacin and decrease its associated AA from water is presented. Initially, the fundamental composition, oxidation states, bandgap, point of zero charge, and morphological characteristics of the NIM were determined, denoting the NIM's feasibility for photocatalytic processes. Consequently, the effectiveness of different advanced processes such as using solar light with the NIM (Light-NIM) and solar light with the NIM and H2O2 (Light-NIM-H2O2) to reduce AA was evaluated. The NIM acts as a semiconductor under solar light, effectively degrading enrofloxacin (ENR) and reducing its AA, although complete elimination was not achieved. The addition of hydrogen peroxide (NIM-Light-H2O2) enhanced the generation of reactive oxygen species (ROS), thereby increasing the elimination of ENR and AA. The role of ROS, specifically O2•- and HO●, in the degradation of enrofloxacin was distinguished using scavenger species and electron paramagnetic resonance (EPR) analysis. Additionally, the five primary degradation products generated during the advanced processes were elucidated. Furthermore, the relationship between the structure of these products and the persistence or elimination of AA, which was differentiated against E. coli but not against S. aureus, was discussed. The effects of the matrix during the process and the extent of the treatments, including their capacity to promote disinfection, were also studied. The reusability of the natural iron material was examined, and it was found that the NIM-Light-H2O2 system showed an effective reduction of 5 logarithmic units in microbiological contamination in an EWWTP and can be reused for up to three cycles while maintaining 100% efficiency in reducing AA.

Green Synthesis of Zinc Oxide Nanoparticles for Tetracycline Adsorption: Experimental Insights and DFT Study

An eco-friendly approach was used to fabricate zinc oxide nanoparticles (ZnO NPs) using thyme, Thymus vulgaris L., leaf extract. The produced ZnO nanoparticles were characterized by XRD and SEM analysis. The ZnO NPs showed remarkable adsorption efficiency for tetracycline (TC) from water systems, with a maximum removal rate of 95% under optimal conditions (10 ppm, 0.10 g of ZnO NPs, pH 8.5, and 30 min at 25 °C). The adsorption kinetics followed the pseudo-2nd-order model, and the adsorption process fitted the Temkin isotherm model. The process was spontaneous, endothermic, and primarily chemisorptive. Quantum chemistry calculations, utilizing electrostatic potential maps and HOMO-LUMO gap analysis, have confirmed the stability of the TC clusters. This study suggests that green synthesis using plant extracts presents an opportunity to generate nanoparticles with properties suitable for real-world applications.

Green synthesis of ZnO nanocubes from Ceropegia omissa H. Huber extract for photocatalytic degradation of bisphenol An under visible light to mitigate water pollution

Plastic pollution has become a major environmental problem because it does not break down and poses risks to ecosystems and human health. This study focuses on the environmentally friendly synthesis of ZnO nanocubes using an extract from Ceropegia omissa H. Huber plant leaves. The primary goal is to investigate the viability of these nanocubes as visible-light photocatalysts for the degradation of bisphenol A (BPA). The synthesized ZnO nanocubes have a highly crystalline structure and a bandgap of 3.1 eV, making them suitable for effective visible-light photocatalysis. FTIR analysis, which demonstrates that the pertinent functional groups are present, demonstrates the chemical bonding and reducing processes that take place in the plant extract. The XPS method also studies zinc metals, oxygen valencies, and binding energies. Under visible light irradiation, ZnO nanocubes degrade BPA by 86% in 30 min. This plant-extract-based green synthesis method provides a long-term replacement for traditional procedures, and visible light photocatalysis has advantages over ultraviolet light. The study's results show that ZnO nanocubes may be good for the environment and can work well as visible light photocatalysts to break down organic pollutants. This adds to what is known about using nanoparticles to clean up the environment. As a result, this study highlights the potential of using environmentally friendly ZnO nanocubes as a long-lasting and efficient method of reducing organic pollutant contamination in aquatic environments.

Photocatalytic Degradation of Antibiotics via Exploitation of a Magnetic Nanocomposite: A Green Nanotechnology Approach toward Drug-Contaminated Wastewater Reclamation

In the quest for eco-conscious innovations, this research was designed for the sustainable synthesis of magnetite (Fe3O4) nanoparticles, using ferric chloride hexahydrate salt as a precursor and extract of Eucalyptus globulus leaves as both a reducing and capping agent, which are innovatively applied as a photocatalyst for the photocatalytic degradation of antibiotics "ciprofloxacin and amoxicillin". Sugar cane bagasse biomass, sugar cane bagasse pyrolyzed biochar, and magnetite/sugar cane bagasse biochar nanocomposite were also synthesized via environmentally friendly organized approaches. The optimum conditions for the degradation of ciprofloxacin and amoxicillin were found to be pH 6 for ciprofloxacin and 5 for amoxicillin, dosage of the photocatalyst (0.12 g), concentration (100 mg/L), and irradiation time (240 min). The maximum efficiencies of percentage degradation for ciprofloxacin and amoxicillin were found to be (73.51%) > (63.73%) > (54.57%) and (74.07%) > (61.55%) > (50.66%) for magnetic nanocomposites, biochar, and magnetic nanoparticles, respectively. All catalysts demonstrated favorable performance; however, the "magnetite/SCB biochar" nanocomposite exhibited the most promising results among the various catalysts employed in the photocatalytic degradation of antibiotics. Kinetic studies for the degradation of antibiotics were also performed, and notably, the pseudo-first-order chemical reaction showed the best results for the degradation of antibiotics. Through a comprehensive and comparative analysis of three unique photocatalysts, this research identified optimal conditions for efficient treatment of drug-contaminated wastewater, thus amplifying the practical significance of the findings. The recycling of magnetic nanoparticles through magnetic separation, coupled with their functional modification for integration into composite materials, holds significant application potential in the degradation of antibiotics.

Degradation of enrofloxacin by a novel Fe-N-C@ZnO material in freshwater and seawater: Performance and mechanism

In this study, we investigated the doping of Fe-N-C with ZnO (Fe-N-C@ZnO) to enhance its performance in the reduction of biological toxicity and degradation of enrofloxacin (ENR) in seawater. The steady-state/transient fluorescence analysis and free radical quenching test indicated an extremely low electron-hole recombination rate and the generation of reactive oxygen species in Fe-N-C@ZnO, leading to an improvement in the energy efficiency. We compared the ENR degradation efficiencies of Fe-N-C@ZnO and ZnO using both freshwater and seawater. In freshwater, Fe-N-C@ZnO exhibited a slightly higher degradation efficiency (95.00%) than ZnO (90.30%). However, the performance of Fe-N-C@ZnO was significantly improved in seawater compared to that of ZnO. The ENR degradation efficiency of Fe-N-C@ZnO (58.87%) in seawater was 68.39% higher than that of ZnO (34.96%). Furthermore, the reaction rate constant for ENR degradation by Fe-N-C@ZnO in seawater (7.31 × 10-3 min-1) was more than twice that of ZnO (3.58 × 10-3 min-1). Response surface analysis showed that the optimal reaction conditions were a pH of 7.42, a photocatalyst amount of 1.26 g L-1, and an initial ENR concentration of 6.56 mg L-1. Fe-N-C@ZnO prepared at a hydrothermal temperature of 128 °C and heating temperature of 300 °C exhibited the optimal performance for the photocatalytic degradation of ENR. Based on liquid chromatography-mass spectrometry analysis, the degradation processes of ENR were proposed as three pathways: two piperazine routes and one quinolone route.

Effective Visible-Light-Driven Photocatalytic Degradation of Harmful Antibiotics Using Reduced Graphene Oxide-Zinc Sulfide-Copper Sulfide Nanocomposites as a Catalyst

In recent decades, antibiotics have been found in aquatic environments, raising severe concerns. In this study, a unique reduced graphene oxide-zinc sulfide-copper sulfide (rGO-ZnS-CuS) nanocomposite (NC) prepared by using a straightforward surfactant-free in situ microwave method was used for antibiotic degradation via photocatalysis. The structural and morphological characteristics of the produced catalysts were characterized using various techniques, confirming the successful development of nanocomposite structures of better quality than that of the pure samples. The photocatalytic degradation of antibiotics containing ofloxacin was also investigated. The results suggest that the rGO-ZCS NC outperformed the other composites in terms of photocatalytic activity toward ofloxacin degradation. Superoxide and hydroxyl radicals were the main active species during the degradation process. According to our results, the catalytic activity of rGO-ZCS NC is much better than that of the other composites.

Green synthesis of copper oxide nanoparticles and its efficiency in degradation of rifampicin antibiotic

In recent ages, green nanotechnology has gained attraction in the synthesis of metallic nanoparticles due to their cost-effectiveness, simple preparation steps, and environmentally-friendly. In the present study, copper oxide nanoparticles (CuO NPs) were prepared using Parthenium hysterophorus whole plant aqueous extract as a reducing, stabilizing, and capping agent. The CuO NPs were characterized via UV-Vis Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), powder X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Dynamic Light Scattering (DLS). The UV-Vis spectra of CuO NPs showed a surface plasmonic resonance band to occur at 340 nm. FTIR analysis revealed the presence of secondary metabolites on the surface of CuO NPs, with a characteristic Cu-O stretching band being identified at 522 cm-1. Scanning electron micrographs and transmission electron micrographs showed that CuO NPs were nearly spherical, with an average particle of 59.99 nm obtained from the SEM micrograph. The monoclinic crystalline structure of CuO NPs was confirmed using XRD, and crystallite size calculated using the Scherrer-Debye equation was found to be 31.58 nm. DLS showed the presence of nanoparticle agglomeration, which revealed uniformity of the CuO NPs. Furthermore, the degradation ability of biosynthesized nanoparticles was investigated against rifampicin antibiotic. The results showed that the optimum degradation efficiency of rifampicin at 98.43% was obtained at 65℃ temperature, 50 mg dosage of CuO NPs, 10 mg/L concentration of rifampicin solution, and rifampicin solution at pH 2 in 8 min. From this study, it can be concluded that CuO NPs synthesized from Parthenium hysterophorus aqueous extract are promising in the remediation of environmental pollution from antibiotics. In this light, the study reports that Parthenium hysterophorus-mediated green synthesis of CuO NPs can effectively address environmental pollution in cost-effective, eco-friendly, and sustainable ways.

Photocatalytic degradation of four emerging antibiotic contaminants and toxicity assessment in wastewater: A comprehensive study

Excessive usage and unrestricted discharge of antibiotics in the environment lead to their accumulation in the ecosystem due to their highly stable and non-biodegradation nature. Photodegradation of four most consumed antibiotics such as amoxicillin, azithromycin, cefixime, and ciprofloxacin were studied using Cu2O-TiO2 nanotubes. Cytotoxicity evaluation of the native and transformed products was conducted on the RAW 264.7 cell lines. Photocatalyst loading (0.1-2.0 g/L), pH (5, 7 and 9), initial antibiotic load (50-1000 μg/mL) and cuprous oxide percentage (5, 10 and 20) were optimized for efficient photodegradation of antibiotics. Quenching experiments to evaluate the mechanism of photodegradation with hydroxyl and superoxide radicals were found the most reactive species of the selected antibiotics. Complete degradation of selected antibiotics was achieved in 90 min with 1.5 g/L of 10% Cu2O-TiO2 nanotubes with initial antibiotic concentration (100 μg/mL) at neutral pH of water matrix. The photocatalyst showed high chemical stability and reusability up to five consecutive cycles. Zeta potential studies confirms the high stability and activity of 10% C-TAC (Cuprous oxide doped Titanium dioxide nanotubes for Applied Catalysis) in the tested pH conditions. Photoluminescence and Electrochemical Impedance Spectroscopy data speculates that 10% C-TAC photocatalyst have efficient photoexcitation in the visible light for photodegradation of antibiotics samples. Inhibitory concentration (IC50) interpretation from the toxicity analysis of native antibiotics concluded that ciprofloxacin was the most toxic antibiotic among the selected antibiotics. Cytotoxicity percentage of transformed products showed r: -0.985, p: 0.01 (negative correlation) with the degradation percentage revealing the efficient degradation of selected antibiotics with no toxic by-products.

Combating Microbial Infections Using Metal-Based Nanoparticles as Potential Therapeutic Alternatives

The nature of microorganisms and the efficiency of antimicrobials have witnessed a huge co-dependent change in their dynamics over the last few decades. On the other side, metals and metallic compounds have gained popularity owing to their effectiveness against various microbial strains. A structured search of both research and review papers was conducted via different electronic databases, such as PubMed, Bentham, Springer, and Science Direct, among others, for the present review. Along with these, marketed products, patents, and Clinicaltrials.gov were also referred to for our review. Different microbes such as bacteria, fungi, etc., and their diverse species and strains have been reviewed and found to be sensitive to metal-carrying formulations. The products are observed to restrict growth, multiplication, and biofilm formation effectively and adequately. Silver has an apt use in this area of treatment and recovery, and other metals like copper, gold, iron, and gallium have also been observed to generate antimicrobial activity. The present review identified membrane disruption, oxidative stress, and interaction with proteins and enzymes to be the primary microbicidal processes. Elaborating the action, nanoparticles and nanosystems are shown to work in our favor in well excelled and rational ways.

Quantum and experimental investigation of the application of Crassostrea gasar (mangrove oyster) shell-based CaO nanoparticles as adsorbent and photocatalyst for the removal of procaine penicillin from aqueous solution

The present study was designed to synthesize and characterize calcium oxide nanoparticles (using mangrove oyster shell as a precursor) and apply the synthesized nanoparticles as a photocatalyst to degrade procaine penicillin in an aqueous solution. The photocatalyst exhibited an average band gap of 4.42 eV, showed a maximum wavelength of absorbance in the UV region (i.e., 280 nm), and is a microporous nanoparticle with a particle diameter of 50 nm. The photocatalyzed degradation of the drug was conducted under natural sunlight, and the influence of parameters such as the period of contact, catalyst load, pH, initial drug concentration, and ionic strength was investigated concerning the degradation profile. The results obtained from response surface analysis indicated that an optimum degradation efficiency of about 93% can be obtained at a concentration, pH, and catalyst dosage of 0.125 M, 2, and 0.20 g respectively, at 0.902 desirabilities. The Langmuir-Hinshelwood, modified Freundlich, parabolic diffusion, pseudo-first-/second-order, and zero-, first-, and second-order kinetic parameters were tested to ascertain the best model that best described the experimental data. Consequently, the Langmuir-Hinshelwood, modified Freundlich, and pseudo-second-order models were accepted based on the minimum error and higher R2 values. Based on the Langmuir-Hinshelwood rate constants for adsorption and photodegradation as well as the evaluated valence bond potential, the degradation of the drug first proceeded through the mechanism of adsorption and followed by the oxidation of the drug by superoxide (generated from the interaction of electrons that generated by through the absorption of UV radiation). The quantum chemical calculation gave evidence that pointed towards the establishment of strong agreement with experimental data and also showed that the carboxyl functional group in the drug is the target site for adsorption and subsequent degradation.

Designed Synthesis of PDI/BiOCl-BiPO4 Composited Material for Boosted Photocatalytic Contaminant Degradation

Enhancing the photocatalytic performance for contaminant degradation to accelerate the large-scale application of photocatalysis still is an enduring challenge. Herein, ternary PDI/BiOCl-BiPO4 composited materials with the different contents of PDI were designed and constructed by the multi-step compound method. The tetracycline hydrochloride and rhodamine B were chosen as targeted pollutants to investigate the photocatalytic performance of PDI/BiOCl-BiPO4 composited materials. The structure and component of BiOCl-BiPO4 and PDI/BiOCl-BiPO4 samples were detailedly characterized by a sequence of physical and chemical characterizations. The optimized PDI/BiOCl-BiPO4 sample, namely PDI(5%)/BiOCl-BiPO4, exhibited the excellent photocatalytic activity for tetracycline hydrochloride and rhodamine B degradation. The major active species that were holes (h+) and superoxide radicals (•O2−) also can be determined in the photocatalytic degradation process by active species trapping experiments. Furthermore, the photoelectrochemical and fluorescence measurements manifest the crucial role of PDI material. It can reduce the recombination of photo-excited charge carrier and improve the separation and transfer of photo-generated electron-hole pairs, which is beneficial to the photocatalytic reaction process. It is anticipated that our work would provide a counterpart to prepare the high-efficiency composited material in heterogeneous photocatalysis.

Upcycling of Acid-Leaching Solutions from Li-Ion Battery Waste Treatment through the Facile Synthesis of Magnetorheological Fluid

The rapidly growing production and usage of lithium-ion batteries (LIBs) dramatically raises the number of harmful wastes. Consequently, the LIBs waste management processes, taking into account reliability, efficiency, and sustainability criteria, became a hot issue in the context of environmental protection as well as the scarcity of metal resources. In this paper, we propose for the first time a functional material—a magnetorheological fluid (MRF) from the LIBs-based liquid waste containing heavy metal ions. At first, the spent battery waste powder was treated with acid-leaching, where the post-treatment acid-leaching solution (ALS) contained heavy metal ions including cobalt. Then, ALS was used during wet co-precipitation to obtain cobalt-doped superparamagnetic iron oxide nanoparticles (SPIONs) and as an effect, the harmful liquid waste was purified from cobalt. The obtained nanoparticles were characterized with SEM, TEM, XPS, and magnetometry. Subsequently, superparamagnetic nanoparticles sized 15 nm average in diameter and magnetization saturation of about 91 emu g−1 doped with Co were used to prepare the MRF that increases the viscosity by about 300% in the presence of the 100 mT magnetic fields. We propose a facile and cost-effective way to utilize harmful ALS waste and use them in the preparation of superparamagnetic particles to be used in the magnetorheological fluid. This work describes for the first time the second life of the battery waste in the MRF and a facile way to remove the harmful ingredients from the solutions obtained after the acid leaching of LIBs as an effective end-of-life option for hydrometallurgical waste utilization.

Efficient remediation of meropenem using Bacillus tropicus EMB20 β-lactamase immobilized on magnetic nanoparticles

Reducing antibiotic pollution in the environment in essential to preserve the effectiveness of the available antibiotics. In the present study, β-lactamase from Bacillus tropicus EMB20 was immobilized onto magnetic nanoparticles (Fe₃O₄) through covalent coupling method. The nanoconjugate was structurally characterized using SEM, FTIR, UV-spectrometry, and XRD diffraction analyses. The prepared enzyme nanoconjugate was thereafter used for remediation of meropenem (Mer) and showed complete removal of 10 mgL^-1 Mer within 3 h of treatment. Moreover, the immobilized enzyme was successfully recovered and reused for up to 5 cycles with 57% removal efficiency. The immobilized preparation was also observed to be effective in the removal of higher Mer concentrations of 25 and 50 mgL^-1 with 79% and 75% removal efficiency, respectively. The major hydrolyzed product of Mer was found to be opened-lactam ring structure with m/z 402.16. The hydrolyzed product(s) were observed to be non-toxic as revealed through microbial MTT, confocal microscopy, and growth studies. Under the mixed conditions of 50 mgL^-1 ampicillin (Amp), 10 mgL^-1 amoxicillin (Amox) and, Mer, the nanoconjugate showed simultaneous complete removal of Amp and Mer, while 49% Amox removal was detected after 3 h of treatment. Moreover, the nanoconjugates also showed concomitant complete removal of antibiotic mixture with in 2 h from aquaculture wastewater. Overall, the study comes out with an efficient approach for remediation of β-lactam antibiotics from contaminated systems.

G-C3N4 Dots Decorated with Hetaerolite: Visible-Light Photocatalyst for Degradation of Organic Contaminants

In this paper, a facile hydrothermal approach was used to integrate graphitic carbon nitride dots (CNDs) with hetaerolite (ZnMn2O4) at different weight percentages. The morphology, microstructure, texture, electronic, phase composition, and electrochemical properties were identified by field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), ultraviolet-visible diffuse reflectance (UV-vis DR), photoluminescence (PL), electrochemical impedance spectroscopy (EIS), Brunauer–Emmett–Teller (BET), Barrett–Joyner–Halenda (BJH), and photocurrent density. The results of XRD, FT-IR, EDX, and XPS analyses confirmed the synthesis of CNDs/ZnMn2O4 (20%) nanocomposite. As per PL, EIS, and photocurrent outcomes, the binary CNDs/ZnMn2O4 nanocomposite revealed superior features for interfacial transferring of charge carriers. The developed p–n heterojunction at the interface of CNDs and ZnMn2O4 nanoparticles partaken a significant role in the impressive charge segregation and migration. The binary nanocomposites were employed for the photodegradation of several dye pollutants, including rhodamine B (RhB), fuchsin, malachite green (MG), and methylene blue (MB) at visible wavelengths. Amongst the fabricated photocatalysts, the CNDs/ZnMn2O4 (20%) nanocomposite gave rise to about 98% RhB degradation efficiency within 45 min with the rate constant of 747 × 10−4 min−1, which was 66.5-, 3.44-, and 2.72-fold superior to the activities of CN, CNDs, and ZnMn2O4 photocatalysts, respectively. The impressive photodegradation performance of this nanocomposite was not only associated with the capacity for impressive visible-light absorption and boosted separation and transport of charge carriers, but also with its large surface area.

Reuse of steel slag as a photocatalyst for tetracycline degradation: mechanism of oxygen vacancies

High value-added utilization of solid waste steel slag for the photocatalytic degradation of tetracycline is realized by alkali activation.

Pulsed-Laser Induced Photolysis of Synthesizing Magnetic Fe3O4 Nanoparticles for Visible-Light Photocatalysis

Our report is the first example describing the successful synthesis of magnetic Fe3O4 nanoparticles (NPs), for which we used pulsed-laser induced photolysis (PLIP). Compared with the previous method of using pulsed-laser ablation of a target, or strong energy of pulsed-laser light to decompose precursors in generating a solvated-ion reaction, the PLIP method used here is dependent on hydrogen peroxide (H2O2) to generate a hydrolysis reaction. Energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were used to demonstrate the Fe3O4 crystalline structure of the synthesized NPs. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images revealed that the average size of the NPs was about 20–50 nm. Regarding their magnetic characteristics, the synthesized NPs exhibited a saturation magnetization of 5.62 emu/g, remanence of 3.82 emu/g, and coercive force of 49.8 Oe. The photocatalytic experiments confirmed that the synthesized magnetic Fe3O4 NPs have visible light-degradation effects based on their ability to photocatalytically degrade methylene blue (MB). The MB degradation efficiency was 60–80% under white-light exposure for 180 min. This study presents a new route for synthesizing magnetic Fe3O4 NPs for their potential use in photocatalysis.

Biosynthesis of iron oxide nanoparticles for the degradation of methylene blue dye, sulfisoxazole antibiotic and removal of bacteria from real water

Water pollution that is caused by dyes, bacteria and antibiotics, has resulted in a threat to living organisms, animals and humans, hence there is a need to synthesize multifunctional materials that can be used for the degradation of various pollutants. The aim of this study was to synthesize Iron oxide (Fe₃O₄) NPs and test this material for photocatalytic degradation and antibacterial activity. The synthesis of Iron oxide (Fe₃O₄) NPs was conducted using M. burkeana extract and characterised using UV-vis, XRD, BET, SEM, EDS and TGA. The material was then tested for its photocatalytic and antibacterial efficiency against methylene blue dye, antibiotic sulfisoxazole and E. coli and S. aureus bacterial strains. XRD confirmed the formation of Fe₃O₄ NPs. UV-vis gave optical information whereby an excitation at 320 nm and a bandgap of 3.74 eV was noted. The deposition of the phytochemicals onto the Fe₃O₄ NPs was demonstrated using FTIR. From the surface analysis, the morphology of the synthesized NPs was found to be rod like and mesoporous. Upon testing for methylene blue degradation, the Fe₃O₄ NPs were more potent under basic conditions (pH 12) and the O₂ radicals were found to be the species responsible for the degradation. Against sulfisoxazole, a 60% degradation was observed. Lastly, when testing these materials against bacterial strains found in tap, pond, river and sewage water, they were potent in particular against gram positive strains. These results show that at optimum conditions, these materials are able to degrade various pollutants in wastewater.

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Biosynthesis of Fe₃0₄ NPs using M. burkeana for the first time.

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99% and 60% degradation of MB dye and antibiotic SSX, respectively.

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Superoxides were the major species responsible for MB degradation.

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Materials could be reused several times.

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High potency against gram positive strains using real water.

Current Developments in the Effective Removal of Environmental Pollutants through Photocatalytic Degradation Using Nanomaterials

Photocatalysis plays a prominent role in the protection of the environment from recalcitrant pollutants by reducing hazardous wastes. Among the different methods of choice, photocatalysis mediated through nanomaterials is the most widely used and economical method for removing pollutants from wastewater. Recently, worldwide researchers focused their research on eco-friendly and sustainable environmental aspects. Wastewater contamination is one of the major threats coming from industrial processes, compared to other environmental issues. Much research is concerned with the advanced development of technology for treating wastewater discharged from various industries. Water treatment using photocatalysis is prominent because of its degradation capacity to convert pollutants into non-toxic biodegradable products. Photocatalysts are cheap, and are now emerging slowly in the research field. This review paper elaborates in detail on the metal oxides used as a nano photocatalysts in the various type of pollutant degradation. The progress of research into metal oxide nanoparticles, and their application as photocatalysts in organic pollutant degradation, were highlighted. As a final consideration, the challenges and future perspectives of photocatalysts were analyzed. The application of nano-based materials can be a new horizon in the use of photocatalysts in the near future for organic pollutant degradation.