Synthesis and characterization of zinc oxide nanostructures and its assessment on enhanced bacterial inhibition and photocatalytic degradation

Structural, morphological, mechanical, and electronic properties of nickel substituted manganese oxide (NixMn1-xO, x= 0.0, 0.2, 0.4) for electronic applications

The structural, morphological, mechanical, and electronic properties of nickel-substituted manganese oxide (NixMn1-xO, where x = 0.0, 0.2, and 0.4) were studied using experimental techniques. The compounds were synthesized using a hydrothermal method. The face-centered cubic structures of the examined compounds were confirmed by XRD. Scanning electron microscopy (SEM) images revealed that the particles were well-shaped, while elemental mapping with energy dispersive spectroscopy (EDS) confirmed that the examined compounds had the appropriate proportions of Ni, Mn, and O. The FT-IR spectroscopy results indicated the respective functional groups. Raman spectroscopy results disclosed the vibration modes of the respective materials. The Tauc plot reveals the semiconducting nature of the compounds. The UV-Vis bandgap study revealed the semiconductor natures of compounds. This demonstrates that these nanoparticles can be used in atom lasers, photovoltaics, and other electronic applications.

Impact of Sn-doping on the optoelectronic properties of zinc oxide crystal: DFT approach

This study aims to provide a concise overview of the behavior exhibited by Sn-doped ZnO crystals using a computational technique known as density functional theory (DFT). The influence of Sn doping on the electronic, structural, and optical properties of ZnO have been explored. Specifically, the wavelength dependent refractive index, extinction coefficient, reflectance, and absorption coefficient, along with electronic band gap structure of the Sn doped ZnO has been examined and analyzed. In addition, X-ray diffraction (XRD) patterns have been obtained to investigate the structural characteristics of Sn-doped ZnO crystals with varying concentrations of Sn dopant atoms. The incorporation of tin (Sn) into zinc oxide (ZnO) has been observed to significantly impact the opto-electronic properties of the material. This effect can be attributed to the improved electronic band structure and optical characteristics resulting from the tin doping. Furthermore, the controllable structural and optical characteristics of tin-doped zinc oxide will facilitate the development of various light-sensitive devices. Moreover, the impact of Sn doping on the optoelectronic properties of ZnO is thoroughly investigated and documented.

Current perspectives of metal-based nanomaterials as photocatalytic antimicrobial agents and their therapeutic modes of action: A review

Efforts to restrict the emergence and progression of multidrug-resistant bacterial strains should heavily involve the scientific community, including government bodies, researchers, and industries, in developing new and effective photocatalytic antimicrobial agents. Such changes warrant the modernization and upscaling of materials synthesis laboratories to support and expedite the mass production of materials at the industrial scale for the benefit of humankind and the environment. Despite the massive volume of publications reporting the potential usage of different types of metal-based nanomaterials as antimicrobial agents, reviews uncovering the similarities and differences among the various products remain lacking. This review details the basic and unique properties of metal-based nanoparticles, their use as photocatalytic antimicrobial agents, and their therapeutic modes of action. It shall be noted that compared to traditional antibiotics, the mode of action of photocatalytic metal-based nanomaterials for killing microorganisms are completely different, despite displaying promising performance against antibiotic-resistant bacteria. Besides, this review uncovers the differences in the mode of actions of metal oxide nanoparticles against different types of bacteria, as well as towards viruses. Last but not least, this review comprehensively describes previous published clinical trials and medical usages involving contemporary photocatalytic antimicrobial agents.

Development of a β-cyclodextrin-modified gold nanoparticle-assisted electromembrane extraction method followed by capillary electrophoresis for methadone determination in plasma

In this study, gold nanoparticles (AuNPs) modified with β-cyclodextrin (β-CD) were used to assist with electromembrane extraction (EME) and were coupled with capillary electrophoresis (CE) and ultraviolet (UV) detection (CE-UV) for the extraction and measurement of methadone from plasma samples. A β-CD-modified AuNP-reinforced hollow fiber (HF) was utilized in this work. The β-CD-modified AuNPs act as an absorbent and provide an extra pathway for the analyte extraction. For obtaining the effect of the presence of β-CD-modified AuNPs in the HF pores, the extraction efficiency of the EME and β-CD-modified AuNPs/EME techniques were compared. Different parameters influencing the extraction efficacy of the EME and β-CD-modified AuNPs/EME methods were optimized. Optimal extractions were performed with 1-octanol as the organic solvent in the supported liquid membrane (SLM), with an applied voltage of 10 V as the driving force across the SLM, and with pH 7.0 in the donor solutions with a stirring speed of 1000 rpm after 20 min and 25 min for the β-CD-modified AuNPs/EME and EME methods, respectively. Under optimal conditions, compared with the EME method, the β-CD-modified AuNPs/EME method exhibited increased extraction efficacy in a short time. The β-CD-modified AuNPs/EME technique demonstrated a lower limit of detection (5.0 ng mL^-1), higher extraction recovery (68%), and a more optimal preconcentration factor (135). Furthermore, this method was successfully utilized for measuring methadone in real plasma samples.

Antibiotic resistomes and their chemical residues in aquatic environments in Africa

The aquatic environment is a hotspot for the transfer of antibiotic resistance to humans and animals. Several reviews have put together research efforts on the presence and distribution of antibiotic resistant bacteria (ARB), antibiotic resistance genes (ARGs), and antibiotic chemical residue (ACRs) in food, hospital wastewater, and even in other aquatic environments. However, these reports are largely focused on data from developed countries, while data from developing countries and especially those in Africa, are only marginally discussed. This review is the first effort that distills information on the presence and distribution of ARGs and ACRs in the African aquatic environments (2012-2021). This review provides critical information on efforts put into the study of ARB, ARGs, and ACRs in aquatic environments in Africa through the lens of the different sub-regions in the continent. The picture provided is compared with those from some other continents in the world. It turns out that the large economies in Africa (South Africa, Nigeria, Tunisia, Kenya) all have a few reports of ARB and ARGs in their aquatic environment while smaller economies in the continent could barely provide reports of these in their aquatic environment (in most cases no report was found) even though they have some reports on resistomes from clinical studies. Interestingly, the frequency of these reports of ARB and ARGs in aquatic environments in Africa suggests that the continent is ahead of the South American continent but behind Europe and Asia in relation to providing information on these contaminants. Common ARGs found in African aquatic environment encode resistance to sulfonamide, tetracycline, β-lactam, and macrolide classes of antibiotics. The efforts and studies from African scientists in eliminating ARB and ARGs from the aquatic environment in Africa are also highlighted. Overall, this document is a ready source of credible information for scientists, policy makers, governments, and regional bodies on ARB, ARGs, and ACRs in aquatic environments in Africa. Hopefully, the information provided in this review will inspire some necessary responses from all stakeholders in the water quality sector in Africa to put in more effort into providing more scientific evidence of the presence of ARB, ARGs, and ACRs in their aquatic environment and seek more efficient ways to handle them to curtail the spread of antibiotic resistance among the population in the continent. This will in turn, put the continent on the right path to meeting the United Nations Sustainable Development Goals #3 and #6, which at the moment, appears to be largely missed by most countries in the continent.

Effect of doping and loading Parameters on photocatalytic degradation of brilliant green using Sn doped ZnO loaded CSAC

Sn doped ZnO loaded cotton stalk activated carbon (Sn-ZnO/CSAC) was prepared by chemical precipitation method, and the products were characterized. The XRD resultants confirm that the presence of hexagonal wurtzite phase of the bare ZnO. Furthermore, particular particle size gradually decreases (21.49 nm) due to doping and loading. UV-Vis absorption intensity of doped/loaded sample was red-shifted and then PL intensity is reduced. The photocatalytic performances of bare, Sn-doped ZnO and Sn-ZnO/CSAC was estimated by photodegradation of brilliant green (BG) under sunlight. The photodegradation of BG dye in 120 min over Sn-doped ZnO/CSAC is nearly 96.52%, which is considerably improved than bare ZnO (72.60%), respectively.

Environmental photochemistry by cobalt doped magnesium ferrites: UV light assisted degradation of anionic azo and cationic thiazine dyes

In the current study, cobalt magnesium ferrites (Mg_0.8-xCo_xFe₂O₄ for x values 0.2, 0.4 and 0.6) nanoparticles are prepared by combustion method. The morphology, optical, structural, photocatalytic, compositional and vibrational properties of Mg_0.8-xCo_xFe₂O₄ by the influence of cobalt doping is investigated. Fourier Transform Infrared (FTIR) Spectroscopy and X-ray diffraction (XRD) confirms the formation of spinel cubic phase of the prepared ferrites samples. The optical band gap energy shows a strong effect on crystallite size and increases from 4.2 to 4.4 eV as the concentration of cobalt gets increased. TEM images of Mg_0.8-xCo_xFe₂O₄ clearly reveal spherical nanoparticles with decreasing particle size which ranges from 16 to 10 nm. EDAX spectrum confirms the existence of Fe, Co, Mg and oxygen. The photocatalytic studies of Mg_0.8-xCo_xFe₂O₄ are performed for anionic and cationic dyes. The rate constant values of methylene blue are found as 0.017/min, 0.019/min and 0.022/min for Mg_0.8-xCo_xFe₂O₄ for x values 0.2, 0.4 and 0.6 respectively. The degradation efficacy of the prepared samples to degrade methylene blue is high (95%) and it indicates that they may be efficient in degrading environmental pollutants and may prove out to be competent photo-catalyst.

Detection of heavy metals, SERS and antibacterial activity of polyvinylpyrolidone modified plasmonic nanoparticles

Selective and sensitive optical sensor based on surface plasmon resonance for detection of various heavy metals in water using polyvinylpyrolidone modified silver nanoparticles was explained in this present study. The prepared nanoparticles were characterized by UV-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscopy (TEM). UV-visible spectra show the surface plasmon resonance (SPR) peak at 409 nm corresponding to silver nanoparticles. Crystalline nature of the nanoparticles was evident from TEM images and XRD analysis. TEM images showed average size of 10 nm for prepared silver nanoparticles. FTIR analysis provides the presence of various functional groups responsible for the reduction and stability of the prepared silver nanoparticles. SERS gives the molecular orientation of the adsorbed pyridine molecules via its nitrogen lone pair of electrons on the surface of silver. Prepared polyvinylpyrolidone modified silver nanoparticles (AgNPs) are demonstrated to detect the concentration of heavy metal contaminant Fe³⁺ ions in water based on linear change in surface plasmon resonance absorption strength. In addition, AgNPs showed promising activity towards E.coli. These observed optical properties suggest the possible utilization of prepared nanoparticles in the application of water purification.

Investigation on characterization, antifouling and cytotoxic properties of zinc oxide nanoparticles biosynthesized by a mangrove-associated actinobacterium Streptomyces olivaceus (MSU3)

The present study was undertaken to biosynthesize zinc oxide nanoparticles (ZnONPs) using a mangrove-associated actinobacterium Streptomyces olivaceus (MSU3) under in vitro conditions. The synthesized ZnONPs were structurally characterized through UV, FT-IR, TG-DTA, XRD, SEM and EDX analysis. Analysis of biosynthesized ZnONPs in UV-Vis spectroscopy showed presence of functional groups between the wavelengths 325 and 380 nm. FT-IR analysis showed the functional groups, such as halo bromide (C-Br), alkyne (C≡C), carboxylic acid (O-H), nitro (N-O), fluoro (C-F), alkene (C=C) and aromatic (R-C-H) groups, respectively, within the wave numbers between 614.30 and 3074.41 cm^-1. The crystalline poly-dispersed quasi spherical nature of ZnONPs expressed the average particle size of 37.9 nm with the 2θ values of 11.802-37.885°. Antibacterial activity of ZnONPs showed pronounced inhibitory zone (25 mm) and least MIC and MBC values (125 and 250 µg ml^-1) against Escherchia sp. In the antifouling study, ZnONPs strongly inhibited byssal thread formation in mussel Perna indica and recorded LC₅₀ value of 424.47 µg ml^-1. Mollusc foot adherence assay inferred that the ZnONPs effectively inhibited settlement of limpet Patella vulgata and showed minimal fouling (26.43%) at 350 µg ml^-1 and recorded LC₅₀ value of 218.77 µg ml^-1. Results of anticrustacean assay depicted that, ZnONPs had registered LC₅₀ value of 676.08 µg ml^-1 against Artemia salina nauplii. From this study, it could be concluded that an eco-friendly approach could be used to open a new avenue for biosynthesis of ZnONPs from a mangrove associated actinobacterium S. olivaceus (MSU3) in antifouling studies.

Efficient photocatalytic degradation of industrial contaminants by Piper longum mediated ZnO nanoparticles

Piper longum extract as a reducing agent in green synthesis method is used to synthesize ZnO nanoparticles (ZnO-NPs). The impact of the reductant on the structural, optical and surface morphological properties of ZnO-NPs can be analyzed. Piper longum extract has delicately tuned the band gap of ZnO-NPs. Increase in energy band gap indicates an increase in the number of capping molecules in the prepared ZnO nanoparticles. The carbohydrates and proteins not only play a fundamental role in ZnO capping, which is important for its stability, determination and biocompatibility. Thus obtained nanosized ZnO particles are confirmed by the surface morphological studies. Because of various surface interface properties might have different physical-chemical, desorption-adsorption abilities in the direction towards microbes, create different antibacterial performances. S.aureus has maximum inhibition zone of 23 mm and Escherichia coli has minimum inhibition zone of 7 mm. To assess the photocatalytic activity of the prepared ZnO-NPs under UV light irradiation, methyl orange, malachite green and methylene blue dyes were utilized as model contaminants. The degradation efficiency of MG, MB and MO dyes solution is found that 96%, 69% and 48% of degradation efficiency respectively under ultraviolet light irradiation. The properties of synthetic nanopowders suggest that they have important potential for a variety of biochemical and environmental applications.

Microwave assisted hydrothermally synthesized cobalt doped zinc ferrites nanoparticles for the degradation of organic dyes and antimicrobial applications

A novel photocatalyst based cobalt doped zinc ferrites nanoparticles (Co-ZnFe₂O₄ NPs) was prepared to actively concentrate degradation of organic dyes in water. The aim this study is to investigate the effect of substitution of Co²⁺ for Zn²⁺ in zinc ferrites nanoparticles and is characterized with UV-visible spectroscopy, XRD, TEM, SEM, Photoluminescence and Vibrating sample magnetometer technique. When the calcinations temperature increases from 150 °C to 450 °C the amorphous ferrites begins to vanish and the characteristic reflections of cubic spinal Co-ZnFe₂O₄ phase are only observed at 450 °C. The band gap energy (E_g) of sample calcined at 250 °C is calculated at 5.2 eV and that of 450 °C is 4.5 eV. The observed value of band gap energy decreased with increasing calcinations temperature in the samples. The increase in PL peak intensity is due to collective emissions and light-scattering. The doping material, cobalt substitution at spinel zinc ferrites surface, and hence gradually decrease the amorphous effect, increase the saturation magnetization and decrease the coercivity while increasing the temperature. The compounds calcined at 250 °C and 450 °C were investigated for their in vitro antimicrobial activity against Staphylococcus aureus. A sample with 450 °C calcination temperature leads to higher efficiencies in the inhibition of growth of bacteria and degradation of organic dyes. Hence, this study provides a novel photocatalyst of Co-ZnFe₂O₄ NPs in the tile to degrade and analyze the environmentally ignored organic compounds.

Environmental photochemistry with Sn/F simultaneously doped TiO2 nanoparticles: UV and visible light induced degradation of thiazine dye

Environmental route such as degradation of toxic dyes can be improved through photochemical activity such as light driven photocatalytic degradation. Herein, fluorine and tin simultaneously doped TiO₂ nanoparticles were synthesized and characterized. The formation of anatase phase in synthesized samples and the reduction in the crystallite size of doped TiO₂ was confirmed from XRD results. The existence of O-Ti-O stretching vibration in pure and co-doped TiO₂ confirmed from FTIR results. Optical studies reveal that the band gap of co-doped TiO₂ is increased and hence it was concluded that the particle size of co-doped TiO₂ is reduced compared with as-synthesized TiO₂. The morphologies of TiO₂ changed significantly with doping of fluorine and tin. It reveals majority of the particles are hexagons, pentagons and ellipse shaped and some of them are spheres with a mean particle size of 31.17 nm. PL studies showed the reduction in intensity for Sn-F/TiO₂ accredited to the lesser recombination rate of electron-hole pair under UV light irradiation. Thus tin and fluorine doped TiO₂ could be considered as a good candidate for photocatalytic activity. The photocatalytic activity of TiO₂ and Sn-F/TiO₂ nanoparticles was analyzed separately through the degradation of methylene blue (MB) under visible and UV light irradiation. The use of Sn and F ions in the synthesis of TiO₂ are revealed not only create small sized nanoparticles but these water soluble nanoparticles have very good antibacterial and antifungal action by inhibiting the growth of bacteria and fungus.

Photocatalytic degradation of organic synthetic dyes and textile dyeing waste water by Al and F co-doped TiO2 nanoparticles

Textile wastewater threatens people health by alluring diseases and revealing public existing close to the waste to the dangerous products within. Because waste causes a risk to the environment and people, waste management making is the main challenge of the municipal world. Environmental process such as toxic dye degradation can be stepped up through photochemical process such as visible light induced catalytic degradation. Here, the successful synthesis of co-doping of Al and F into TiO₂ nanoparticles (Al-F∕TiO₂ NPs) by solid state reaction method comprising different proportions of co-dopants is evaluated for the applications of degrading organic synthetic dyes and textile dyeing waste water. Influence of co-dopants was studied in their optical, structural, compositional, morphological and vibrational properties. The average crystallite size of Al-F∕TiO₂ NPs was found as 15 nm.FTIR and UV-vis spectrum confirmed F and Al atoms were incorporated into the TiO₂ lattice.The absorption edges slightly moved to shorter wavelength by increasing level of dopants and this specifies the control of optical absorption of TiO₂ by the incorporation of F and Al³⁺ ions.The EDS spectrum indicates the purity of the samples. The highest zone of inhibition for the prepared nanoparticles over Staphylococcus aureus reached to 22 mm. The rate constant (k_app) value of MB, MO and textile waste water is 0.0138/min, 0.0174/min and 0.0139/min for the prepared nanoparticles respectively. The study of photocatalytic degradation of visible light assisted MB, MO and real textile waste water by Al-F∕TiO₂ NPs revealed that the prepared nanoparticles act as ideal catalyst by tuning the concentration of co-dopants in TiO₂.

Nanotechnology, Green Synthesis and Biological Activity Application of Zinc Oxide Nanoparticles Incorporated Argemone Mxicana Leaf Extract

Nanomaterial is a rapidly growing area that is used to create a variety of new materials and nanotechnology applications from medical, pharmaceuticals, chemical, mechanical, electronics and several environmental industries including physical, chemical and biological nanoparticles are very important in our daily life. Nanoparticles with leaf extract from the healthy plant are important in the area of research using biosynthesis methods. Because of it's used as an environmentally ecofriendly, other than traditional physical and chemical strategies. In particular, biologically synthesized nanoparticles have become a key branch of nanotechnology. The present work presents a synthesis of zinc oxide nanoparticles using an extract from the Argemone leaf Mexicana. Biosynthetic nanoparticles are characterized by X-ray diffraction (XRD), Ultraviolet visible (UV-vis) spectroscopy analysis, a Fourier Transform Infrared Spectroscopy analysis (FTIR) and a scanning electron microcopy (SEM), X-ray analysis with dispersive energy (EDAX). XRD is used to examine the crystalline size of zinc oxide nanoparticles. The FTIR test consists in providing evidence of the presence of targeted teams. UV is used for optical properties and calculates the energy of the bandwidth slot. The scanning microscope emission reveals the morphology of the surface and the energy dispersive X-ray analysis confirms the basic composition of zinc oxide nanoparticles. It is found that zinc nanoparticles are capable of achieving high anti-fungal efficacy and therefore have a high potential antimicrobial activity of ZnO NPs, like antibacterial and high antioxidant. Zinc Oxide nanoparticles from the Argemone Mexicana leaf extract have several antimicrobial applications, such as medical specialty, cosmetics, food, biotechnology, nano medicine and drug delivery system. ZnO nanoparticles are important because they provide many practical applications in industry. The most important use of nanoparticles of ZnO would be strong antibacterial and antioxidant activity with a simple and efficient biosynthesis method may be used for future work applications.

Influence of Sn4+ ion on band gap tailoring, optical, structural and dielectric behaviors of ZnO nanoparticles

II-VI semiconductors are being attracted due to excellent optical and electronic behaviors when they utilize for device fabrication. Among II-VI semiconductors, Zinc oxide finds cutting-edge results for various applications with a lack of toxicity. Sn⁴⁺ ion incorporated ZnO nanoparticles have been synthesized using a soft chemical route and characterized for the investigation of properties like structural, morphological, elemental, optical and dielectric responses. The prepared ZnO had a hexagonal structure and the particles size reduces by the influence of Sn⁴⁺ ion: this reduction rate increases for the increase of doping ratio. The average particles size was estimated within 24-34 nm. TEM, HRTEM and SEM results corroborate the structural aspects noticed using XRPD study. UV-vis study results showed that a blue shift on the optical band gap was received for high doping concentration (10 at.%) of Sn⁴⁺. PL peaks were observed in the UV region for 0 at.% and 2 at.% Sn⁴⁺ doped ZnO nanoparticles, and the peak position was shifted from UV to violet and blue region for 10 at.% Sn⁴⁺ doped ZnO nanoparticles. The dielectric permittivity was reduced due to the addition of Sn⁴⁺ ions. The AC conductivity was increased for higher doping concentrations. The Sn⁴⁺ ion incorporated ZnO nanoparticles shall be useful for various applications including LED fabrication for blue emission and also it is suitable to act as a buffer material in solar panel.

Ameliorative photocatalytic dye degradation of hydrothermally synthesized bimetallic Ag-Sn hybrid nanocomposite treated upon domestic wastewater under visible light irradiation

Industrial and textile dyes are the major source of water pollutants in the Coimbatore Districts of Tamil Nadu, India. The highly stable organic dyes from these industries are being discharged untreated into neighboring rivers, lakes, and ponds. Thus, the present study mainly focused on the preparation of bimetallic nanocomposite (Ag-Sn) through Free-facile Teflon autoclave methodology and their subsequent stimulation has given to the photocatalyst by visible light irradiation. This visible light stimulates and irradiates the photocatalysts from steady state to the excited state and might help in absorption of the nanosized dye materials and organic matter. The nanocomposite was characterized using UV, FTIR, Zeta-sizer, XRD and FE-SEM. These parameters exhibited significant lattice structures with an average size of 127.6 nm. Further the nanocomposite treated samples were tested for water quality parameters like TDS, BOD, COD, heavy metals, sedimentation rate and bacterial population. Likewise, the samples irradiated with visible light for photocatalytic activity exhibited a significant intensity of C/C₀ at 0.42 and 0.28. The treated water used for green gram seedling assay exhibited significant growth. Scavengers from Ag-Sn bimetallic nanocomposite plays the major role in dye degradation. The results clearly suggest that Ag-Sn bimetallic nanocomposite can be used for wastewater treatment and the subsequent treated water can be utilized for agriculture purposes.

Effective removal of pharmaceutical impurities and nutrients using biocatalyst from the municipal wastewater with moving bed packed reactor

The presence of antibiotics in the wastewater is one of the important issues related to environmental management. In this study, antibiotics-degrading bacteria were screened from the enriched sewage sludge sample. Among the isolated bacterial strains, Bacillus subtilis AQ03 showed maximum antibiotic tolerance (>2000 ppm). The characterized strain B. subtilis AQ03 degraded sulfamethaoxazole and sulfamethoxine and the optimum nutrient and physical-factors were analyzed. B. subtilis AQ03 degraded 99.8 ± 1.3 % sulfamethaoxazole, and 93.3 ± 6.2 % sulfamethoxine. Sodium nitrate and ammonium chloride were improved antibiotics degradation (<90 %). The optimized conditions were maintained in a moving bed bioreactor for the removal of antibiotics and nutrients from the wastewater. The selected strain considerably produced proteases (109.4 U/mL), amylases (55.1 U/mL), cellulase (9.6 U/mL) and laccases (15.2). In moving bed reactor, sulfamethaoxazole degradation was maximum after 8 days (100 ± 1.5 %) and sulfamethoxazole (100 ± 0) was removed completely from wastewater after 10 days. In moving bed reactor, biological oxygen demand (92.1 ± 2.8 %), chemical oxygen demand (79.6 ± 1.2 %), nitrate (89.4 ± 3.9 %) and phosphate (91.8 ± 1.2) were removed from the wastewater along with antibiotics after 10 days of treatment. The findings indicate that the indigenous bacterial communities and the ability to survive in the presence of high antibiotic concentrations and xenobiotics. Moving bed bioreactor is useful for the removal of nutrients and antibiotics from wastewater.

Investigation on (Zn) doping and anionic surfactant (SDS) effect on SnO2 nanostructures for enhanced photocatalytic RhB dye degradation

Herein we reported the effect of doping and addition of surfactant on SnO₂ nanostructures for enhanced photocatalytic activity. Pristine SnO₂, Zn-SnO₂ and SDS-(Zn-SnO₂) was prepared via simple co-precipitation method and the product was annealed at 600 °C to obtain a clear phase. The structural, optical, vibrational, morphological characteristics of the synthesized SnO₂, Zn-SnO₂ and SDS-(Zn-SnO₂) product were investigated. SnO₂, Zn-SnO₂ and SDS-(Zn-SnO₂) possess crystallite size of 20 nm, 19 nm and 18 nm correspondingly with tetragonal structure and high purity. The metal oxygen vibrations were present in FT-IR spectra. The obtained bandgap energies of SnO₂, Zn-SnO₂ and SDS-(Zn-SnO₂) were 3.58 eV, 3.51 eV and 2.81 eV due to the effect of dopant and surfactant. This narrowing of bandgap helped in the photocatalytic activity. The morphology of the pristine sample showed poor growth of nanostructures with high level of agglomeration which was effectively reduced for other two samples. Product photocatalytic action was tested beneath visible light of 300 W. SDS-(Zn-SnO₂) nanostructure efficiency showed 90% degradation of RhB dye which is 2.5 times higher than pristine sample. Narrow bandgap, crystallite size, better growth of nanostructures paved the way for SDS-(Zn-SnO₂) to degrade the toxic pollutant. The superior performance and individuality of SDS-(Zn-SnO₂) will makes it a potential competitor on reducing toxic pollutants from wastewater in future research.

Visible light assisted photocatalytic degradation of commercial dyes and waste water by Sn-F co-doped titanium dioxide nanoparticles with potential antimicrobial application

The disintegration of natural water sources signals out the scarcity of adam's ale and will be hurdle for the human physical state. So it is necessary to decrease waste loads and hence pressure on the ecology for the sustainability of fishery and dye industry. Herein, TiO₂ nanoparticles doped with Sn and F are synthesized and the influence of simultaneous doping on the optical, surface morphological, structural, photocatalytic and antibacterial activities are investigated. Doping of TiO₂ with Sn and F suppress the growth of both anatase and rutile phase because of the dissimilar boundaries. All the prepared doped and undoped samples are found to possess tetragonal structure. The influence of F and Sn in TiO₂ lattice is recognized with the XRD and FT-IR spectra of the prepared particles The size of the obtained nanoparticles decreases as increasing concentration of F and Sn. TiO₂ is showing the presence of spherical and ellipsoidal nanoparticles whereas doped samples showing nanobulk, pentagons and rods. The absorption edge of the doped samples are blue shifted with increasing concentration of dopants indicates the control of optical absorption property of TiO_2. The visible light assisted photocatalytic degradation of fish processing waste water by doped and undoped samples are found to be established as 0.0076/min and 0.0071/min respectively. Visible light assisted degradation of commercially available dyes and fish processing waste water is assessed. Methyl blue showed enhanced photocatalytic activity under visible light irradiation compared to Methyl orange. It is observed that all the prepared particles show good antimicrobial activity against Staphylococcus aureus.

Sunlight-driven enhanced photocatalytic activity of bandgap narrowing Sn-doped ZnO nanoparticles

In this paper, we grab to utilize one of the trending techniques with efficient implications in wastewater treatment of organic pollutants, the photocatalytic degradation method shining out in the research field. Herein, tin (Sn)-doped zinc oxide (ZnO) nanoparticles (NPs) (Sn/ZnO) with different doping concentrations (1, 2, 3, 4, and 5 wt%) were synthesized via a simple co-precipitation assisted method and later subjected for their physico-chemical, morphological, and optical characterization. In addition, photocatalytic activity as the concerned study was investigated as to record the different doping levels of Sn/ZnO to examine the effect of doping concentration in relation with the degradation efficiency. We know that the optical bandgap of pure ZnO was 3.26 eV while it tends to increase slightly upon increasing the doping concentration. In the present investigation, methylene blue (MB) dye was used as a model pollutant to evaluate the photocatalytic activity of Sn/ZnO photocatalysts under natural sunlight. Varied doping concentrations of Sn/ZnO were compared with different characterization techniques while XRD analysis shows up 4-Sn/ZnO with sharp peak at (1 0 1) plane with smaller grain size in comparison to other Sn/ZnO samples. The morphological recognition depicts the hexagonal structure with smaller size for 4-Sn/ZnO which offers more active sites with improved photocatalytic activity, higher surface area for the transportation of pollutants. Fluorescence spectra results revealed that Sn dopant suppresses the charge carrier recombination. The lower intensity of PL indicated reduced recombination rate, which resulted in enhancing the photocatalytic activity. To investigate the possible mechanism, kinetics and reusability studies were performed. The 4% Sn-doped ZnO nanoparticle concentration showed highest photocatalytic activity when compared with other doping levels.