Phycosynthesis and Enhanced Photocatalytic Activity of Zinc Oxide Nanoparticles Toward Organosulfur Pollutants

Application of green synthesized Ag and Cu nanoparticles for the control of bruchids and their impact on seed quality and yield in greengram

Storage pests, particularly bruchids, are major biotic constraints causing significant storage losses in pulses. Conventional control methods relying on insecticides and fumigants often lead to food contamination due to toxic pesticide residues and a rapid decline in seed germination. In this investigation, through green nano-technological application, a promising and sustainable alternative for pest management is developed. Silver and copper nanoparticles were synthesized through ocimum leaf extract. The characterization of silver and copper nanoparticles was carried out by UV-spectroscopy, particle size analyzer, scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared. Both the nanoparticles were spherical and crystalline in nature. Greengram seeds were primed with standardized silver and copper nanoparticles at different concentrations (1000, 1500, and 2000 ppm) and compared with castor-treated, deltamethrin-treated, and untreated control seeds for seed quality, growth, and yield. After one month of storage, all the pulse beetles released in different treatments exhibited 100 % mortality, whereas in control, the insects multiplied. At the end of nine months, the control seeds had shown 72 % damage and 39.67 % germination. In contrast, silver nanoparticles at 1000 ppm showed no seed damage and achieved 81.67 % germination, which was on par with copper nanoparticles at 1000 ppm with 79.33 % germination. Seed priming of silver and copper nanoparticles at 1000 ppm also demonstrated superior performance in all the seed quality and biochemical parameters (alpha amylase and catalase) throughout the storage period. Whereas, in the greenhouse experiment, enhanced growth (35.96 cm, 46.48 cm, and 53.00 cm at 30, 60 DAS, and at harvest, respectively) and yield per plant (3.75 g) were significantly higher in plants that were given foliar application with silver nanoparticles at 1000 ppm. Furthermore, foliar application of these nanoparticles at all concentrations (1000, 1500, and 2000 ppm) did not exhibit any adverse effects on soil microbial organisms, as assessed by dehydrogenase enzyme activity. Hence, this research highlights the potential use of silver and copper nanoparticles at 1000 ppm as effective tools for storage pest management and contributing to improved agricultural productivity and sustainability.

Topical gel formulations as potential dermal delivery carriers for green-synthesized zinc oxide nanoparticles

This study aimed to incorporate green-synthesized zinc oxide nanoparticles (ZnO NPs), functionalized with polyethylene glycol (PEG) and linked to doxorubicin (DOX), into various topical gel formulations (hydrogel, oleogel, and bigel) to enhance their dermal delivery. The ZnO NPs were produced using the aqueous extract of the root hair of Phoenix dactylifera. The optimized green-synthesized ZnO NPs, PEGylated and conjugated to DOX, demonstrated a particle size below 100 nm, low polydispersity index, and zeta potential between - 11 and - 19 mV. The UV-Vis spectroscopy analysis confirmed characteristic absorption peaks at 351 and 545 nm for ZnO and DOX, respectively. The transmission electron microscope (TEM) images revealed well-dispersed spherical nanoparticles without aggregation. Additionally, ZnO NPs-loaded gels exhibited uniformity, cohesion, no phase separation, pseudoplastic flow, and viscoelastic properties. The in vitro release studies showed that DOX-PEG-ZnO NPs hydrogel released 99.5% of DOX after 5 h of starting the release. Moreover, the penetration of DOX-PEG-ZnO NPs through excised rat skin was visualized by TEM. In conclusion, the hydrogel formulation containing green-synthesized DOX-PEG-ZnO NPs holds great promise for dermal administration in skin cancer treatment. Furthermore, the release rate and skin penetration of DOX from gels were varied based on the type of gel matrix and corroborated with their corresponding rheological properties.

C. S, Anil VS, Raghavan S. Phytosynthesis of silver nanoparticles using aqueous sandalwood (Santalum album L.) leaf extract: Divergent effects of SW-AgNPs on proliferating plant and cancer cells

The biogenic approach for the synthesis of metal nanoparticles provides an efficient eco-friendly alternative to chemical synthesis. This study presents a novel route for the biosynthesis of silver nanoparticles using aqueous sandalwood (SW) leaf extract as a source of reducing and capping agents under mild, room temperature synthesis conditions. The bioreduction of Ag+ to Ago nanoparticles (SW-AgNPs) was accompanied by the appearance of brown color, with surface plasmon resonance peak at 340-360 nm. SEM, TEM and AFM imaging confirm SW-AgNP's spherical shape with size range of 10-32 nm. DLS indicates a hydrodynamic size of 49.53 nm with predominant negative Zeta potential, which can contribute to the stability of the nanoparticles. FTIR analysis indicates involvement of sandalwood leaf derived polyphenols, proteins and lipids in the reduction and capping of SW-AgNPs. XRD determines the face-centered-cubic crystalline structure of SW-AgNPs, which is a key factor affecting biological functions of nanoparticles. This study is novel in using cell culture methodologies to evaluate effects of SW-AgNPs on proliferating cells originating from plants and human cancer. Exposure of groundnut calli cells to SW-AgNPs, resulted in enhanced proliferation leading to over 70% higher calli biomass over control, enhanced defense enzyme activities, and secretion of metabolites implicated in biotic stress resistance (Crotonyl isothiocyanate, Butyrolactone, 2-Hydroxy-gamma-butyrolactone, Maltol) and plant cell proliferation (dl-Threitol). MTT and NRU were performed to determine the cytotoxicity of nanoparticles on human cervical cancer cells. SW-AgNPs specifically inhibited cervical cell lines SiHa (IC50-2.65 ppm) and CaSki (IC50-9.49 ppm), indicating potential use in cancer treatment. The opposing effect of SW-AgNPs on cell proliferation of plant calli (enhanced cell proliferation) and human cancer cell lines (inhibition) are both beneficial and point to potential safe application of SW-AgNPs in plant cell culture, agriculture and in cancer treatment.

Microalgae as a potential natural source for the green synthesis of nanoparticles

The increasing global population is driving the development of alternative sources of food and energy, as well as better or new alternatives for health and environmental care, which represent key challenges in the field of biotechnology. Microalgae represent a very important source material to produce several high-value-added bioproducts. Due to the rapid changes in the modern world, there is a need to build new materials for use, including those in the nanometer size, although these developments may be chronological but often do not occur at a time. In the last few years, a new frontier has opened up at the interface of biotechnology and nanotechnology. This new frontier could help microalgae-based nanomaterials to possess new functions and abilities. Processes for the green synthesis of nanomaterials are being investigated, and the availability of biological resources such as microalgae is continuously being examined. The present review provides a concise overview of the recent advances in the synthesis, characterization, and applications of nanoparticles formed using a wide range of microalgae-based biosynthesis processes. Highlighting their innovative and sustainable potential in current research, our study contributes towards the in-depth understanding and provides latest updates on the alternatives offered by microalgae in the synthesis of nanomaterials.

A comparative study on green synthesis and characterization of Mn doped ZnO nanocomposite for antibacterial and photocatalytic applications

Biological and green synthesis of nanomaterial is a superior choice over chemical and physical methods due to nanoscale attributes implanted in a green chemistry matrix, have sparked a lot of interest for their potential uses in a variety of sectors. This research investigates the growing relevance of nanocomposites manufactured using ecologically friendly, green technologies. The transition to green synthesis correlates with the worldwide drive for environmentally sound procedures, limiting the use of traditional harsh synthetic techniques. Herein, manganese was decorated on ZnO NPs via reducing agent of Withania-extract and confirmed by UV-spectrophotometry with highest peak at 1:2 ratio precursors, and having lower bandgap energy (3.3 eV). XRD showed the sharp peaks and confirms the formation of nanoparticles, having particle size in range of 11-14 nm. SEM confirmed amorphous tetragonal structure while EDX spectroscopy showed the presence of Zn and Mn in all composition. Green synthesized Mn-decorated ZnO-NPs screened against bacterial strains and exhibited excellent antimicrobial activities against gram-negative and gram-positive bacteria. To check further, applicability of synthesized Mn-decorated Zn nanocomposites, their photocatalytic activity against toxic water pollutants (methylene blue (MB) dye) were also investigated and results showed that 53.8% degradation of MB was done successfully. Furthermore, the installation of green chemistry in synthesizing nanocomposites by using plant extract matrix optimizes antibacterial characteristics, antioxidant and biodegradability, helping to build sustainable green Mn decorated ZnO nanomaterial. This work, explains how biologically friendly Mn-doped ZnO nanocomposites can help reduce the environmental impact of traditional packaging materials. Based on these findings, it was determined that nanocomposites derived from biological resources should be produced on a wide scale to eradicate environmental and water contaminants through degradation.

Bioinspired Stevia rebaudiana Green Zinc Oxide Nanoparticles for the Adsorptive Removal of Antibiotics from Water

Green zinc oxide nanoparticles (ZnO NPs) synthesized using Stevia rebaudiana as a reducing agent were investigated as ecofriendly adsorbents for the removal of the antibiotics ciprofloxacin (CIP) and tetracycline (TET) from water. Green ZnO NPs were synthesized using a rapid novel approach that did not require annealing or calcination at high temperatures to produce mesoporous NPs with a size range of 37.36-71.33 nm, a specific surface area of 15.28 m2/g, and a negative surface charge of -15 mV at pH 5. The green ZnO NPs exhibited an antioxidant activity of 85.57% at 250 μg/mL and an antibacterial activity with MIC and MBC of 50 and 100 mg/mL, respectively, against both Escherichia coli and Staphylococcus aureus. The best adsorption performance was achieved using a 4 g/L dose and pH 5, yielding, respectively, 86.77 ± 0.82% removal and 27.07 ± 0.26 mg/g adsorption capacity for CIP at 10 mg/L and 67.86 ± 3.41% and 15.88 ± 0.37 mg/g for TET at 25 mg/L. The green ZnO NPs achieved 79.71% ± 0.28 and 61.55% ± 0.53 removal of 10 mg/L CIP and 25 mg/L TET, respectively, in a spiked tap water binary system of the two contaminants. Adsorption of CIP and TET occurred mainly via electrostatic interactions, whereby CIP was bound more strongly than TET by virtue of its charge and size. The synthesis and adsorption processes were evaluated by a stepwise regression statistical model to optimize their parameters. Lastly, the green ZnO NPs were regenerated and reused for 5 cycles, indicating their functionality as simple, reusable, and low-cost adsorbents for the removal of CIP and TET from wastewater, in accordance with SDGs #6 and 12 for the sustainable management of water.

Enhancement of mechanical and barrier properties of chitosan-based bionanocomposites films reinforced with eggshell-derived hydroxyapatite nanoparticles

In this study, Hydroxyapatite nanoparticles (HANPs), derived from eggshell waste, were employed to reinforce chitosan biopolymer-based films through the solvent-casting method. The impact of varying HANPs content (1%, 3%, 5%, and 10 wt %) in bionanocomposites was investigated. The influence of HANPs addition on the final film properties was comprehensively analyzed using Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA), mechanical (tensile) testing, and Water Vapor Permeability (WVP). The morphological aspects of bionanocomposites and the dispersion of nanoparticles within the matrix were studied using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD). The structural changes in the films were probed using Fourier-Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) techniques. Results indicated that the addition of 1% and 3% of HANPs exhibited a higher glass transition temperature and improved thermal stability in bionanocomposites. Films with 3% HANPs content exhibited a notable increase in tensile strength, showing a 61.54% increase, while films with 1% HANPs content displayed a 52% reduction in WVP compared to pristine chitosan films. These findings underscore the significant potential of chitosan-hydroxyapatite bionanocomposite films for applications in food packaging applications.

A Review on Nanomaterial as Photocatalysts for Degradation of Organic Pollutants

Eliminating hazardous organic contaminants from water is a major concern today. Nanomaterials with their textural features, large surface area, electrical conductivity, and magnetic properties make them efficient for the removal and photocatalytic degradation of organic pollutants. The reaction mechanisms of the photocatalytic oxidation of common organic pollutants were critically examined. A detailed review of articles published on photocatalytic degradation of hydrocarbons, pesticides, and dyes was presented therein. This review seeks to bridge information gaps on the reported nanomaterial as photocatalysts for the degradation of organic pollutants under sub-headings, nanomaterials, organic pollutants, degradation of organic pollutants, and mechanisms of photocatalytic activities.

Functionalized ZnO-Based Nanocomposites for Diverse Biological Applications: Current Trends and Future Perspectives

The wide array of structures and characteristics found in ZnO-based nanostructures offers them a versatile range of uses. Over the past decade, significant attention has been drawn to the possible applications of these materials in the biomedical field, owing to their distinctive electronic, optical, catalytic, and antimicrobial attributes, alongside their exceptional biocompatibility and surface chemistry. With environmental degradation and an aging population contributing to escalating healthcare needs and costs, particularly in developing nations, there's a growing demand for more effective and affordable biomedical devices with innovative functionalities. This review delves into particular essential facets of different synthetic approaches (chemical and green) that contribute to the production of effective multifunctional nano-ZnO particles for biomedical applications. Outlining the conjugation of ZnO nanoparticles highlights the enhancement of biomedical capacity while lowering toxicity. Additionally, recent progress in the study of ZnO-based nano-biomaterials tailored for biomedical purposes is explored, including biosensing, bioimaging, tissue regeneration, drug delivery, as well as vaccines and immunotherapy. The final section focuses on nano-ZnO particles' toxicity mechanism with special emphasis to their neurotoxic potential, as well as the primary toxicity pathways, providing an overall review of the up-to-date development and future perspectives of nano-ZnO particles in the biomedicine field.

Green-route synthesis and ab-initio studies of a highly efficient nano photocatalyst:Ce/zinc-oxide nanopetals

In the present work, Zinc-oxide nanostructures and Ce/Zinc-oxide nanopetals were synthesized by a new environmentally friendly green synthesis method using the Withania coagulans plant. Cerium nitrate Ce(NO3)3 and zinc nitrate Zn(NO3)2 were used as precursors. The prepared nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet spectroscopy (UV-vis). Crystal planes (100), (002), (101), (102), (110), (103), (200), (112) and (201) at 2θ 31.75°, 34.35°, 36.2°, 47.55°, 56.6°, 62.75°, 66.3°, 67.9°, and 69.09° respectively confirmed the hexagonal wurtzite crystal structure of Zinc-oxide. Angular shifts for Ce1% doped Zinc-oxide and Ce3% doped Zinc-oxide nanopetal nanostructures were observed in the (100) and (101) planes of the crystal. More specifically, using Scherrer's equation, the crystallite sizes of Zinc-oxide, Ce1% doped Zinc-oxide nanopetals, Ce3% doped Zinc-oxide nanopetals, and Ce5% doped Zinc-oxide nanopetals were 16.48 ± 02 nm, 17.8 ± 2 nm, 18.8 ± 2 nm, and 18.87 ± 2 nm, respectively. The pure Zinc-oxide grain had the appearance of a nanoflower. On the other hand, the nanopetal structure of Ce5% doped Zinc-oxide nanopetals had oval-shaped nanopetal morphology. The absorption peaks were observed at 373, 376.4, 377, and 378 nm for Zinc-oxide, Ce1% doped Zinc-oxide nanopetals, Ce3% doped Zinc-oxide nanopetals, and Ce5% doped Zinc-oxide nanopetals, respectively, which results in a progressive redshift. The gap energies of Zinc-oxide, Ce1% doped Zinc-oxide nanopetals, Ce3% doped Zinc-oxide nanopetals, and Ce5% doped Zinc-oxide nanopetals were 2.796, 2.645, 2.534, and 2.448 eV, respectively. Photodegradation under visible light (>400 nm) indicates the high efficiency of the photocatalyst based on Ce5% doped Zinc-oxide nanopetals. DFT calculations, structural changes, charge analysis, and electronic band structures were carried out to confirm the experiment.

Synthesis and characterization of titanium dioxide nanoparticles from Bacillus subtilis MTCC 8322 and its application for the removal of methylene blue and orange G dyes under UV light and visible light

Over the last decade there has been a huge increase in the green synthesis of nanoparticles. Moreover, there is a continuous increase in harnessing the potential of microorganisms for the development of efficient and biocompatible nanoparticles around the globe. In the present research work, investigators have synthesized TiO2 NPs by harnessing the potential of Bacillus subtilis MTCC 8322 (Gram-positive) bacteria. The formation and confirmation of the TiO2 NPs synthesized by bacteria were carried out by using UV-Vis spectroscopy, Fourier transforms infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDX/EDS). The size of the synthesized TiO2 NPs was 80-120 nm which was spherical to irregular in shape as revealed by SEM. FTIR showed the characteristic bands of Ti-O in the range of 400-550 cm-1 and 924 cm-1 while the band at 2930 cm-1 confirmed the association of bacterial biomolecules with the synthesized TiO2 NPs. XRD showed two major peaks; 27.5° (rutile phase) and 45.6° (anatase phase) for the synthesized TiO2 NPs. Finally, the potential of the synthesized TiO2 NPs was assessed as an antibacterial agent and photocatalyst. The remediation of Methylene blue (MB) and Orange G (OG) dyes was carried out under UV- light and visible light for a contact time of 150-240 min respectively. The removal efficiency for 100 ppm MB dye was 25.75% and for OG dye was 72.24% under UV light, while in visible light, the maximum removal percentage for MB and OG dye was 98.85% and 80.43% respectively at 90 min. Moreover, a kinetic study and adsorption isotherm study were carried out for the removal of both dyes, where the pseudo-first-order for MB dye is 263.269 and 475554.176 mg/g for OG dye. The pseudo-second-order kinetics for MB and OG dye were 188.679 and 1666.667 mg/g respectively. In addition to this, the antibacterial activity of TiO2 NPs was assessed against Bacillus subtilis MTCC 8322 (Gram-positive) and Escherichia coli MTCC 8933 (Gram-negative) where the maximum zone of inhibition in Bacillus subtilis MTCC 8322 was about 12 mm, and for E. coli 16 mm.

Synthesis, characterization, and antibacterial activity of chitosan-chelated silver nanoparticles

Bacterial infections pose a significant threat to human health and safety, necessitating the urgent resolution of the problem through the development and implementation of highly effective antibacterial agents. However, the emergence of multidrug-resistant bacteria has diminished the satisfactory effectiveness of antibacterial treatments. To overcome this obstacle, we developed effective antibacterial agents by chemical reduction for inhibiting bacterial proliferation and inducing membrane damage. Specifically, four different types of chitosan/Ag nanoparticle (CS-AgNPs-i) (i-1, 2, 3, 4) complexes were synthesized by varying the quantity of chitosan added during the synthesis process. We found that the amount of CS does not affect the morphology and size of CS-AgNPs-i, which remained at approximately 20 nm and all CS-AgNPs were mostly spherical. The zeta potential measurements indicated that the surface of CS-AgNPs carries a positive charge. Notably, elevating the chitosan concentration led to a more pronounced antibacterial impact, particularly evident in its interaction with the peptidoglycan layer on the bacterial surface. Our experimental results undeniably establish the potent antibacterial efficacy of CS-AgNPs against both Escherichia coli and Staphylococcus aureus. Employing live/dead bacterial staining, we reveal the marked capability of CS-AgNPs to effectively hinder bacterial proliferation. Furthermore, our experimental investigations revealed that CS-AgNPs possess broad-spectrum antimicrobial activity. The results of in vitro cytotoxicity experiments substantiated the high biocompatibility of CS-AgNPs with elevated chitosan loading. The study provides valuable insights into the development of nano-antibacterial agents that exhibit significant potential as a substitute to replace traditional antibiotics for medical applications.

ZnO nanoparticles mediated by Azadirachta indica as nano fertilizer: Improvement in physiological and biochemical indices of Zea mays grown in Cr-contaminated soil

The current investigation aimed at evaluating the impact of Azadirachta indica-mediated zinc oxide nanoparticles (Ai-ZnONPs) on the growth and biochemical characteristics of maize (sweet glutinous 3000) under exposure to 50 mg kg-1Ai-ZnONPs with Cr (VI) concentrations of 50 and 100 mg kg-1. The results indicate that plants exposed to Cr (VI) only experienced a decline in growth parameters. Conversely, the inclusion of Ai-ZnONPs caused a noteworthy increase in physiological traits. Specifically, shoot and root fresh weight increased by 28.02% and 16.51%, and 63.11% and 97.91%, respectively, when compared to Cr-50 and 100 treatments. Additionally, the SPAD chlorophyll of the shoot increased by 91.08% and 15.38% compared to Cr-50 and 100 treatments, respectively. Moreover, the antioxidant enzyme traits of plant shoot and root, such as superoxide dismutase (SOD 7.44% and 2.70%, and 4.45% and 3.53%), catalase (CAT 1.18% and 3.20%, and 5.03% and 5.78%), and peroxidase (POD 0.31% and 5.55%, and 4.72% and 3.61%), exhibited significant increases in Cr 50 and 100 treatments, respectively. The addition of Ai-ZnONPs to the soil also enhanced soil nutrient status and reduced Cr (VI) concentrations by 40.69% and 19.82% compared to Cr-50 and 100 treated soils. These findings suggest that Ai-ZnONPs can trigger the activation of biochemical pathways that enable biomass accumulation in meristematic cells. Further investigations are required to elucidate the mechanisms involved in growth promotion.

Biogenic fabrication of ZnO@EC and MgO@EC using Eucalyptus leaf extract for the removal of hexavalent chromium Cr(VI) ions from water

Zinc and magnesium oxide nanoparticles were fabricated using green synthesis method for the sequestration of hexavalent chromium Cr(VI) from the aqueous medium. The biogenically prepared ZnO@EC and MgO@EC nanoparticles were successfully loaded on the Eucalyptus. The prepared nanomaterials were characterized using various techniques such as FESEM, TGA, XRD, EDX, FTIR, BET, and elemental mapping. FE-SEM analysis has revealed the surface morphology of ZnO nanoparticles, which were rod-like and spherical in shape, whereas MgO nanoparticles were of irregular shape. Batch mode was selected to remove the hexavalent chromium from aqueous solution using the prepared nanomaterials. The Cr(VI) adsorption was carried out under optimized conditions, viz., pH (3.0), adsorbent dose (0.05 g), contact time (150 min), temperature (25 ± 2 °C), and initial concentration (50 mg/L). The experimental results were compared using the different isotherm models; The observations have indicated that experimental data fit better with Freundlich (R2 = 0.99) and Langmuir (R2 = 0.99) isotherms, respectively. The maximum adsorption capacity of ZnO@EC and MgO@EC for Cr(VI) was found to be 49.3 and 17.4 mg/g, respectively. The regeneration study of the adsorbents was conducted using different desorbing agents viz., ethanol, NaOH, and NaCl. The desorbing agent NaOH performed better and showed removal percentage of 34.24% and 20.18% for ZnO@EC and MgO@EC, respectively, after the three reusability cycles. The kinetics of reaction was assessed using the pseudo-first-order and pseudo-second-order kinetic models. The experimental data of both the nanomaterials ZnO@EC and MgO@EC obeyed pseudo-second-order model with correlation coefficient values 0.999 and 0.983, respectively. The thermodynamic study confirmed that adsorption was feasible, spontaneous, and endothermic. The adsorbents were tested for spiked real water which confirms their applicability and potential in real water systems also. The results indicated fair removal of chromium suggesting applicability of both adsorbents.

An Overview of Renal Cell Carcinoma Hallmarks, Drug Resistance, and Adjuvant Therapies

Renal neoplasms are highlighted as one of the 10 most common types of cancer. Renal cell carcinoma (RCC) is the most common type of renal cancer, considered the seventh most common type of cancer in the Western world. The most frequently altered genes described as altered are VHL, PBRM1, SETD2, KDM5C, PTEN, BAP1, mTOR, TP53, TCEB1 (ELOC), SMARCA4, ARID1A, and PIK3CA. RCC therapies can be classified in three groups: monoclonal antibodies, tyrosine kinase inhibitors, and mTOR inhibitors. Besides, there are targeted agents to treat RCC. However, frequently patients present side effects and resistance. Even though many multidrug resistance mechanisms already have been reported to RCC, studies focused on revealing new biomarkers as well as more effective antitumor therapies with no or low side effects are very important. Some studies reported that natural products, such as honey, epigallocatechin-3-gallate (EGCG), curcumin, resveratrol, and englerin A showed antitumor activity against RCC. Moreover, nanoscience is another strategy to improve RCC treatment and reduce the side effects due to the improvement in pharmacokinetics and reduction of toxicities of chemotherapies. Taking this into account, we conducted a systemic review of recent research findings on RCC hallmarks, drug resistance, and adjuvant therapies. In conclusion, a range of studies reported that RCC is characterized by high incidence and increased mortality rates because of the development of resistance to standard therapies. Given the importance of improving RCC treatment and reducing adverse effects, nanoscience and natural products can be included in therapeutic strategies.

Microbial synthesis of titanium dioxide nanoparticles and their importance in wastewater treatment and antimicrobial activities: a review

Nanotechnology (NT) and nanoparticles (NPs) have left a huge impact on every field of science today, but they have shown tremendous importance in the fields of cosmetics and environmental cleanup. NPs with photocatalytic effects have shown positive responses in wastewater treatment, cosmetics, and the biomedical field. The chemically synthesized TiO2 nanoparticles (TiO2 NPs) utilize hazardous chemicals to obtain the desired-shaped TiO2. So, microbial-based synthesis of TiO2 NPs has gained popularity due to its eco-friendly nature, biocompatibility, etc. Being NPs, TiO2 NPs have a high surface area-to-volume ratio in addition to their photocatalytic degradation nature. In the present review, the authors have emphasized the microbial (algae, bacterial, fungi, and virus-mediated) synthesis of TiO2 NPs. Furthermore, authors have exhibited the importance of TiO2 NPs in the food sector, automobile, aerospace, medical, and environmental cleanup.

Colorimetric sensor based on biogenic nanomaterials for high sensitive detection of hydrogen peroxide and multi-metals

Hydrogen peroxide (H2O2) and heavy metals, which are among the wastes of the industrial sector, become a threat to living things and the environment above certain concentrations. Therefore, the detection of both H2O2 and heavy metals with simple, low-cost, and fast analytical methods has gained great importance. The use of nanoparticles in colorimetric sensor technology for the detection of these analytes provides great advantages. In recent years, green synthesis of nanomaterials with products that can be considered biowaste is among the popular topics. In this study, silver/silver chloride nanoparticles (Ag@AgCl NPs) were synthesized using the green synthesis method as an eco-friendly and cheap method, the green algae extract was used as a reducing agent. The characterization of Ag@AgCl nanoparticles and green algae extract was carried out with several techniques such as Transmission Electron Microscopy (TEM), UV-Visible spectrometry (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction patterns (XRD) methods were used for characterization. According to TEM analysis, the Ag@AgCl NPs typically spherical in form and range in size from 4 to 10 nm, and UV-vis showed the formation of surface plasmon resonance (SPR) of the Ag@AgCl between 400 and 450 nm. In addition, its activity as a colorimetric sensor for hydrogen peroxide (H2O2) and multi-metal detection was evaluated. Interestingly, Ag/AgCl NPs caused different color formations for 3 metals simultaneously in the sensor study for heavy metal detection, and Fe3+, Cu2+, and Cr6+ ions were detected. The R2 values for H2O2, Fe3+, Cu2+, and Cr6+ were 0.9360, 0.9961, 0.9787, and 0.9625 the limit of detection (LOD) was 43.75, 1.69, 3.18, and 5.05 ppb (ng/mL), respectively. It was determined that Ag@AgCl NPs have the potential to be used as a colorimetric sensor for the detection of H2O2 and heavy metals from wastewater.

Recent advances in the synthesis, characterization and biomedical applications of zinc oxide nanoparticles

Zinc oxide nanoparticles (ZnONPs) have become the widely used metal oxide nanoparticles and drawn the interest of global researchers due to their biocompatibility, low toxicity, sustainability and cost-effective properties. Due to their unique optical and chemical properties, it emerges as a potential candidate in the fields of optical, electrical, food packaging and biomedical applications. Biological methods using green or natural routes are more environmentally friendly, simple and less use of hazardous techniques than chemical and/or physical methods in the long run. In addition, ZnONPs are less harmful and biodegradable while having the ability to greatly boost pharmacophore bioactivity. They play an important role in cell apoptosis because they enhance the generation of reactive oxygen species (ROS) and release zinc ions (Zn2+), causing cell death. Furthermore, these ZnONPs work well in conjunction with components that aid in wound healing and biosensing to track minute amounts of biomarkers connected to a variety of illnesses. Overall, the present review discusses the synthesis and most recent developments of ZnONPs from green sources including leaves, stems, bark, roots, fruits, flowers, bacteria, fungi, algae and protein, as well as put lights on their biomedical applications such as antimicrobial, antioxidant, antidiabetic, anticancer, anti-inflammatory, antiviral, wound healing, and drug delivery, and modes of action associated. Finally, the future perspectives of biosynthesized ZnONPs in research and biomedical applications are discussed.

Biosynthesis approach of zinc oxide nanoparticles for aqueous phosphorous removal: physicochemical properties and antibacterial activities

In this study, phosphorus (PO43--P) is removed from water samples using zinc oxide nanoparticles (ZnO NPs). These nanoparticles are produced easily, quickly, and sustainably using Onion extracts (Allium cepa) at an average crystallite size of 8.13 nm using the Debye-Scherrer equation in the hexagonal wurtzite phase. The characterization and investigation of bio-synthesis ZnO NPs were carried out. With an initial concentration of 250 mg/L of P, the effects of the adsorbent dose, pH, contact time, and temperature were examined. At pH = 3 and T = 300 K, ZnO NPs achieved the optimum sorption capacity of 84 mg/g, which was superior to many other adsorbents. The isothermal study was found to fit the Langmuir model at a monolayer capacity of 89.8 mg/g, and the kinetic study was found to follow the pseudo-second-order model. The adsorption process was verified to be endothermic and spontaneous by thermodynamic characteristics. As a result of their low cost as an adsorbent and their high metal absorption, ZnO NPs were found to be the most promising sorbent in this investigation and have the potential to be used as effective sorbents for the removal of P from aqueous solutions. The antimicrobial activity results showed that ZnO NPs concentration had greater antibacterial activity than conventional Cefotaxime, which was utilized as a positive control in the inhibitory zone. However, no inhibitory zone was visible in the controlled wells that had been supplemented with onion extract and DMSO.

Green synthesis of zinc oxide nanoparticles using lychee peel and its application in anti-bacterial properties and CR dye removal from wastewater

In nanoscience and nanobiotechnology, using plant extracts in synthesizing metal nanoparticles (NPs) has recently come to light as an exciting opportunity with several benefits over traditional physicochemical methods. In the present work, zinc oxide (ZnO) based nanoparticles (NPs) were synthesized by green chemistry route using lychee peel extract to capture hazardous congo red dye from wastewater and illustrate their antimicrobial behavior. The X-Ray Diffraction (XRD) spectra confirm the wurtzite crystal structure, and Fourier Transform Infrared (FTIR) spectra confirm the functional group in ZnO, which is suitable for dye adsorption. It was found that the NPs were spherical and had a size of <10 nm. The synthesized ZnO NPs could effectively remove >98% of CR dye from wastewater within 120 min of contact time at a wide pH range from 2 to 10. The primary mechanism involved in removing dye was the electrostatic interaction between ZnO adsorbent and CR dye. The antimicrobial performance of synthesized ZnO NPs was found to show 34% inhibition against Bacillus subtilis (ATCC 6538), 52% against Escherichia coli (ATCC 11103), 58% against Pseudomonas aeruginosa (ATCC 25668) and 32% against Staphylococcus aureus (ATCC 25923) using well diffusion assay. ZnO demonstrates a suitable anti-bacterial property over both gram-positive and gram-negative pathogenic bacteria. Overall, the green synthesized method for developing ZnO NPs shows promising and significant anti-bacterial performance and is a highly potential adsorbent for removing CR dye from wastewater.

The Antibacterial Activities and Characterizations of Biosynthesized Zinc Oxide Nanoparticles, and Their Coated with Alginate Derived from Fucus vesiculosus

Zinc oxide nanoparticles have many advantages for nano-biotechnologists due to their intense biomedical applications. ZnO-NPs are used as antibacterial agents, which influence bacterial cells through the rupture of the cell membrane and the generation of reactive free radicals. Alginate is a polysaccharide of natural origin due to its excellent properties that are used in various biomedical applications. Brown algae are good sources of alginate and are used as a reducing agent in the synthesis of nanoparticles. This study aims to synthesize ZnO-NPs by using brown alga Fucus vesiculosus (Fu/ZnO-NPs) and also to extract alginate from the same alga, which is used in coating the ZnO-NPs (Fu/ZnO-Alg-NCMs). The characterizations of Fu/ZnO-NPs and Fu/ZnO-Alg-NCMs were determined by FTIR, TEM, XRD, and zeta potential. The antibacterial activities were applied against multidrug resistance bacteria of both gram-positive and negative. The results obtained in FT-TR showed there are some shifts in the peak positions of Fu/ZnO-NPs and Fu/ZnO-Alg-NCMs. The peak at 1655 cm^-1, which assigned amide I-III, is present in both Fu/ZnO-NPs and Fu-Alg-ZnO-NCMs; this band is responsible for bio-reductions and stabilization of both nanoparticles. The TEM images proved the Fu/ZnO-NPs have rod shapes with sizes ranging from 12.68 to 17.66 and are aggregated, but Fu/ZnO/Alg-NCMs are spherical in shape with sizes ranging from 12.13 to 19.77. XRD-cleared Fu/ZnO-NPs have nine sharp peaks that are considered good crystalline, but Fu/ZnO-Alg-NCMs have four broad and sharp peaks that are considered semi-crystalline. Both Fu/ZnO-NPs and Fu/ZnO-Alg-NCMs have negative charges (-1.74 and -3.56, respectively). Fu/ZnO-NPs have more antibacterial activities than Fu/ZnO/Alg-NCMs in all tested multidrug-resistant bacterial strains. Fu/ZnO/Alg-NCMs had no effect on Acinetobacter KY856930, Staphylococcus epidermidis, and Enterobacter aerogenes, whereas there was an apparent effect of ZnO-NPs against the same strains.

Recent Advances and Perspectives of Nanomaterials in Agricultural Management and Associated Environmental Risk: A Review

The advancement in nanotechnology has enabled a significant expansion in agricultural production. Agri-nanotechnology is an emerging discipline where nanotechnological methods provide diverse nanomaterials (NMs) such as nanopesticides, nanoherbicides, nanofertilizers and different nanoforms of agrochemicals for agricultural management. Applications of nanofabricated products can potentially improve the shelf life, stability, bioavailability, safety and environmental sustainability of active ingredients for sustained release. Nanoscale modification of bulk or surface properties bears tremendous potential for effective enhancement of agricultural productivity. As NMs improve the tolerance mechanisms of the plants under stressful conditions, they are considered as effective and promising tools to overcome the constraints in sustainable agricultural production. For their exceptional qualities and usages, nano-enabled products are developed and enforced, along with agriculture, in diverse sectors. The rampant usage of NMs increases their release into the environment. Once incorporated into the environment, NMs may threaten the stability and function of biological systems. Nanotechnology is a newly emerging technology, so the evaluation of the associated environmental risk is pivotal. This review emphasizes the current approach to NMs synthesis, their application in agriculture, interaction with plant-soil microbes and environmental challenges to address future applications in maintaining a sustainable environment.

Algal Extracts for Green Synthesis of Zinc Oxide Nanoparticles: Promising Approach for Algae Bioremediation

Zinc oxide nanoparticles (ZnO-NPs) possess unique properties, making them a popular material across various industries. However, traditional methods of synthesizing ZnO-NPs are associated with environmental and health risks due to the use of harmful chemicals. As a result, the development of eco-friendly manufacturing practices, such as green-synthesis methodologies, has gained momentum. Green synthesis of ZnO-NPs using biological substrates offers several advantages over conventional approaches, such as cost-effectiveness, simplicity of scaling up, and reduced environmental impact. While both dried dead and living biomasses can be used for synthesis, the extracellular mode is more commonly employed. Although several biological substrates have been successfully utilized for the green production of ZnO-NPs, large-scale production remains challenging due to the complexity of biological extracts. In addition, ZnO-NPs have significant potential for photocatalysis and adsorption in the remediation of industrial effluents. The ease of use, efficacy, quick oxidation, cost-effectiveness, and reduced synthesis of harmful byproducts make them a promising tool in this field. This review aims to describe the different biological substrate sources and technologies used in the green synthesis of ZnO-NPs and their impact on properties. Traditional synthesis methods using harmful chemicals limit their clinical field of use. However, the emergence of algae as a promising substrate for creating safe, biocompatible, non-toxic, economic, and ecological synthesis techniques is gaining momentum. Future research is required to explore the potential of other algae species for biogenic synthesis. Moreover, this review focuses on how green synthesis of ZnO-NPs using biological substrates offers a viable alternative to traditional methods. Moreover, the use of these nanoparticles for industrial-effluent remediation is a promising field for future research.

Green Synthesis of Zinc Oxide Nanoparticles Using Nostoc sp. and Their Multiple Biomedical Properties

Zinc oxide nanoparticles (ZnONPs) are the top candidate in the field of biological applications because of their high surface area and excellent catalytic activities. In the present study, the cyanobacteria-mediated biosynthesis of zinc oxide NPs using Nostoc sp. extract as a stabilizing, chelating, and reducing agent is reported. ZnONPs were biologically synthesized using an eco-friendly and simple technique with a minimal reaction time and calcination temperature. Various methods, including X-ray diffraction (XRD), ultraviolet spectroscopy (UV), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) were used to characterize the biosynthesized zinc oxide NPs. XRD analysis depicted the crystalline form of zinc oxide NPs, and the Scherrer equation determined a mean crystalline size of ~28.21 nm. The SEM results reveal the spherical shape of the biosynthesized nanoparticles. Various functional groups were involved in the capping and stabilization of the zinc oxide NPs, which were confirmed by FTIR analysis. The zinc oxide NPs showed strong UV-vis absorption at 340 nm. Multiple in vitro biological applications showed significant therapeutic potential for zinc oxide NPs. Potential antimicrobial assays were reported for zinc oxide NPs via the disc-diffusion method and food poisoning method, respectively. All other activities mentioned below are described with the concentration and IC50 values. Biocompatibility with human erythrocytes and macrophages (IC50: 433 µg/mL, IC50 > 323 µg/mL) and cytotoxic properties using brine shrimps (IC50: 11.15 µg/mL) and Leishmania tropics (Amastigotes IC50: 43.14 µg mL−1 and Promastigotes IC50: 14.02 µg mL−1) were determined. Enzyme inhibition assays (protein kinase and alpha amylase) were performed and showed strong potential. Free radical scavenging tests showed strong antioxidant capacities. These results indicate that zinc oxide NPs synthesized by Nostoc sp. have strong biological applications and are promising candidates for clinical development.

One-step hydrothermal preparation of Ta-doped ZnO nanorods for improving decolorization efficiency under visible light

In this work, Ta-doped ZnO (Ta-ZnO) nanomaterials were synthesized by the hydrothermal method at different temperatures (110, 150, and 170 °C) for the photodegradation of methylene blue (MB) under visible light. Ta doping significantly affects the crystal defects, optical properties, and MB photocatalytic efficiency of ZnO materials. The optical absorption edge of Ta-ZnO 150 was redshifted compared to undoped ZnO, correlating to bandgap narrowing (E _gTa-ZnO = 2.92 eV; E _gZnO = 3.07 eV), implying that Ta doped ZnO is capable of absorbing visible light. Besides, Ta-doping was the reason for enhanced blue light emission in the photoluminescence spectrum, which is related to the oxygen defect V ⁰ _O. It is also observed in the XPS spectra, where the percentage of oxygen in the oxygen-deficient regions (O_531.5 eV) of Ta-ZnO150 is higher than that of ZnO150. It is an important factor in enhancing ZnO's photocatalytic efficiency. The MB degradation efficiency of Ta-doped ZnO reached the highest for Ta-ZnO 150 and was 2.5 times higher than ZnO under a halogen lamp (HL). Notably, the influence of hydrothermal temperature on the structural, morphological, and photoelectrochemical properties was discussed in detail. As a result, the optimal hydrothermal temperature for synthesizing the nanorod is 150 °C. Furthermore, photocatalytic experiments were also performed under simulated sunlight and natural sunlight. The nature of the photo-oxidative degradation of MB was also investigated.

Advancement in algal bioremediation for organic, inorganic, and emerging pollutants

Rapidly changing bioremediation prospects are key drive to develop sustainable options that can offer extra benefits rather than only environmental remediation. Algal remediating is gaining utmost attention due to its mesmerising sustainable features, removing odour and toxicity, co-remediating numerous common and emerging inorganic and organic pollutants from gaseous and aqueous environments, and yielding biomass for a range of valuable products refining. Moreover, it also improves carbon footprint via carbon-capturing offers a better option than any other non-algal process for several high CO₂-emitting industries. Bio-uptake, bioadsorption, photodegradation, and biodegradation are the main mechanisms to remediate a range of common and emerging pollutants by various algae species. Bioadsorption was a dominant remediation mechanism among others implicating surface properties of pollutants and algal cell walls. Photodegradable pollutants were photodegraded by microalgae by adsorbing photons on the surface and intracellularly via stepwise photodissociation and breakdown. Biodegradation involves the transportation of selective pollutants intracellularly, and enzymes help to convert them into simpler non-toxic forms. Robust models are from the green microalgae group and are dominated by Chlorella species. This article compiles the advancements in microalgae-assisted pollutants remediation and value-addition under sustainable biorefinery prospects. Moreover, filling the knowledge gaps, and recommendations for developing an effective platform for emerging pollutants remediation and realization of commercial-scale algal bioremediation.

Bioremediation of Hazardous Wastes Using Green Synthesis of Nanoparticles

Advanced agronomic methods, urbanisation, and industrial expansion contaminate air, water and soil, globally. Agricultural and industrial activities threaten living biota, causing biodiversity loss and serious diseases. Strategies such as bioremediation and physiochemical remediation have not been effectively beneficial at treating pollutants. Metal-based nanoparticles (NPs) such as copper, zinc, silver, gold, etc., in various nanoformulations and nanocomposites are used more and more as they effectively resist the uptake of toxic compounds via plants by facilitating their immobilisation. According to studies, bio-based NP synthesis is a recent and agroecologically friendly approach for remediating environmental waste, which is effective against carcinogens, heavy metal contamination, treating marine water polluted with excessive concentrations of phosphorus, nitrogen and harmful algae, and hazardous dye- and pesticide-contaminated water. Biogenic resources such as bacteria, fungi, algae and plants are extensively used for the biosynthesis of NPs, particularly metallic NPs. Strategies involving green synthesis of NPs are nontoxic and could be employed for commercial scale production. Here, the focus is on the green synthesis of NPs for reduction of hazardous wastes to help with the clean-up process.

Biosynthesis and Anti-inflammatory Activity of Zinc Oxide Nanoparticles Using Leaf Extract of Senecio chrysanthemoides

Nanotechnology has recently appeared as an important study subject in modern material sciences. Greener synthesis of nanoparticles has gained the attention of many scientists because of its integral characteristics such as effectiveness, eco-friendly, and low cost. In the present study by following the green synthesis approach, zinc oxide nanoparticles (ZnO NPs) were formed for the very first time by using Senecio chrysanthemoides leaf extract as a reducing agent. The UV-Vis spectrophotometer was used to study the synthesized ZnO NPs, and the specific peak was found to be at 349 nm. The characteristic Fourier transform infrared (FTIR) peak was found to be at 449 cm^-1 which displays the peak of ZnO molecules. The surface morphology of the ZnO NPs was determined via scanning electron microscopy (SEM). The energy-dispersive X-ray spectroscopy (EDX) study showed that the synthesized ZnO NPs are present at the weight percentage of 66.38%. The X-ray diffraction (XRD) spectrum confirmed the hexagonal phase wurtzite structure, with the average particle size of 31 nm, and demonstrated the crystalline structure of ZnO NPs. Additionally, to all these experiments, we compared the anti-inflammatory properties of biogenic ZnO NPs to a standard drug. Biosynthesized ZnO NPs have revealed an effective anti-inflammatory activity at a higher concentration (100 mL^-1) and showed 73% inhibition in comparison with diclofenac sodium drug. Zinc oxide was shown to be compatible with diclofenac sodium, according to the results. The ZnO NPs produced using the greener synthesis process have the potential to be used in a broad range of fields and also used as a good anti-inflammatory agent.

Bacillus sp. extract used to fabricate ZnO nanoparticles for their antagonist effect against phytopathogens

In order to achieve the food demand of a growing population, agricultural productivity needs to be increased by employing safe strategies. In the present study we have evaluated ZnONPs that were synthesized from the culture supernatant of Bacillus subtilis. Bio mimetically synthesized ZnONPs showed a surface resonance peak of 355 nm corresponding to NPs formation. Further, NPs were examined for their size, shape and element confirmation by DLS, AFM, SEM, TEM and EDAX, which confirmed the synthesized NPs were nearly spherical in size with average diameter of 32 nm by TEM. Surface charge of + 34.3 mV was observed for NPs with a low poly-dispersity index of 0.21. In vitro efficacy studies against fungi Colletotrichum capsici, Sclerotium rolfsii, Alternaria solani and Fusarium oxysporum f. sp. cicero showed up to 99% mycelial growth inhibition at 0.125% ZnONPs. Further, in-vitro disk-diffusion assay showed inhibition zones of 23 ± 0.4 mm and 12.67 ± 0.24 mm for Xanthomonas axonopodis pv. punicae (Xap) and Xanthomonas oryzae pv. oryzae (Xoo) bacterial cultures. Plant toxicity study was observed that ≤ 0.14% NPs concentration was safe under greenhouse conditions. Overall, the present study emphasizes the potential effect of ZnONPs against agricultural pathogens which play an important role in agriculture production.

Biosynthesis of zinc oxide nanoparticles via endophyte Trichoderma viride and evaluation of their antimicrobial and antioxidant properties

The biogenic method for synthesis of nanoparticles is preferred over the traditional strategies, on account of its ease, environmental friendliness, and cost-effectivity, wherein fungi endorse themselves to be the most appropriate precursor for the same. In recent times numerous metal nanoparticles have been reported to exhibit significant therapeutic activities, out of which Zinc Oxide nanoparticles (ZnO NPs) stand apart on account of their multidimensional nature. Thus, this study was carried out with an aim to biosynthesize ZnO NPs utilizing endophyte Trichoderma viride, isolated from the seeds of Momordica charantia. The physicochemical characterization of NPs was done via employing a combination of spectroscopic and microscopic techniques. The NPs were found to have a hexagonal shape and possessed an average particle size of around 63.3 nm. The antimicrobial activity of NPs was evaluated against multi-drug resistant organisms and it was observed to be an appreciable one whereas the antioxidant activity was deduced to be dose-dependent. Thus, these ZnO NPs can be considered as a probable active ingredient of any future therapeutic conceptualization after undertaking a thorough toxicological assessment.

Covalent and Non-covalent Functionalized Nanomaterials for Environmental Restoration

Nanotechnology has emerged as an extraordinary and rapidly developing discipline of science. It has remolded the fate of the whole world by providing diverse horizons in different fields. Nanomaterials are appealing because of their incredibly small size and large surface area. Apart from the naturally occurring nanomaterials, synthetic nanomaterials are being prepared on large scales with different sizes and properties. Such nanomaterials are being utilized as an innovative and green approach in multiple fields. To expand the applications and enhance the properties of the nanomaterials, their functionalization and engineering are being performed on a massive scale. The functionalization helps to add to the existing useful properties of the nanomaterials, hence broadening the scope of their utilization. A large class of covalent and non-covalent functionalized nanomaterials (FNMs) including carbons, metal oxides, quantum dots, and composites of these materials with other organic or inorganic materials are being synthesized and used for environmental remediation applications including wastewater treatment. This review summarizes recent advances in the synthesis, reporting techniques, and applications of FNMs in adsorptive and photocatalytic removal of pollutants from wastewater. Future prospects are also examined, along with suggestions for attaining massive benefits in the areas of FNMs.

Phyco-Synthesized Zinc Oxide Nanoparticles Using Marine Macroalgae, Ulva fasciata Delile, Characterization, Antibacterial Activity, Photocatalysis, and Tanning Wastewater Treatment

The aqueous extract of marine green macroalgae, Ulva fasciata Delile, was harnessed for the synthesis of zinc oxide nanoparticles (ZnO-NPs). The conversion to ZnO-NPs was characterized by color change, UV–vis spectroscopy, FT-IR, TEM, SEM-EDX, and XRD. Data showed the formation of spherical and crystalline ZnO-NPs with a size range of 3–33 nm. SEM-EDX revealed the presence of Zn and O in weight percentages of 45.3 and 31.62%, respectively. The phyco-synthesized ZnO-NPs exhibited an effective antibacterial activity against the pathogenic Gram-positive and Gram-negative bacteria. The bacterial clear zones ranged from 21.7 ± 0.6 to 14.7 ± 0.6 mm with MIC values of 50–6.25 µg mL−1. The catalytic activity of our product was investigated in dark and visible light conditions, using the methylene blue (MB) dye. The maximum dye removal (84.9 ± 1.2%) was achieved after 140 min in the presence of 1.0 mg mL−1 of our nanocatalyst under the visible light at a pH of 7 and a temperature of 35 °C. This percentage was decreased to 53.4 ± 0.7% under the dark conditions. This nanocatalyst showed a high reusability with a decreasing percentage of ~5.2% after six successive cycles. Under the optimum conditions, ZnO-NPs showed a high efficacy in decolorizing the tanning wastewater with a percentage of 96.1 ± 1.7%. Moreover, the parameters of the COD, BOD, TSS, and conductivity were decreased with percentages of 88.8, 88.5, 96.9, and 91.5%, respectively. Moreover, nano-ZnO had a high efficacy in decreasing the content of the tanning wastewater Cr (VI) from 864.3 ± 5.8 to 57.3 ± 4.1 mg L−1 with a removal percentage of 93.4%.

Recent and Emerging Trends in Remediation of Methylene Blue Dye from Wastewater by Using Zinc Oxide Nanoparticles

Due to the increased demand for clothes by the growing population, the dye-based sectors have seen fast growth in the recent decade. Among all the dyes, methylene blue dye is the most commonly used in textiles, resulting in dye effluent contamination. It is carcinogenic, which raises the stakes for the environment. The numerous sources of methylene blue dye and their effective treatment procedures are addressed in the current review. Even among nanoparticles, photocatalytic materials, such as TiO2, ZnO, and Fe3O4, have shown greater potential for photocatalytic methylene blue degradation. Such nano-sized metal oxides are the most ideal materials for the removal of water pollutants, as these materials are related to the qualities of flexibility, simplicity, efficiency, versatility, and high surface reactivity. The use of nanoparticles generated from waste materials to remediate methylene blue is highlighted in the present review.

A facile hydrothermal synthesis of high-efficient NiO nanocatalyst for preparation of 3,4-dihydropyrimidin-2(1H)-ones

The present work introduces a one-step and facile hydrothermal procedure as a green process for the first time to synthesize nickel(II) oxide (NiO) nanoparticles. The as-prepared nanomaterials were used as high efficient, low toxic and cost catalyst for the synthesis of some organic compounds. Ni(NO₃)₂ and some natural extract were used as a surfactant for the first time to synthesis NiO nanomaterials. A high synthesis yield (91%) was obtained for S₂. Rietveld analysis affirmed the cubic crystal system of the obtained NiO nanocatalyst. The morphology studies were carried out with the FESEM method and the images revealed a change from non-homogenous to homogenous spherical particles when the Barberryas was used instead of orange blossom surfactant. Besides, the images revealed that the particle size distribution was in the range of 20 to 60 nm. The synthesized catalysts were used for the first time in Biginelli multicomponent reactions (MCRs) for the preparation of 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) under the present facile reaction conditions. High yield (97%) of the final product was achieved at the optimum condensation reaction conditions (Catalyst: 60 mg; temperature: 90 °C and time: 90 min) when ethyl acetoacetate/methyl acetoacetate (1 mmol), benzaldehyde (1 mmol) and urea (1.2 mmol) were used. A kinetic study affirmed pseudo-first-order model for Biginelli reactions followed the pseudo-first-order model.

Synthesis of the Porous ZnO Nanosheets and TiO2/ZnO/FTO Composite Films by a Low-Temperature Hydrothermal Method and Their Applications in Photocatalysis and Electrochromism

In this paper, porous zinc oxide (ZnO) nanosheets were successfully prepared by a simple low-temperature hydrothermal method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) tests showed that the synthesized product was ZnO with porous sheet structure. The diameter of porous nanosheets was about 100 nm and the thickness was about 8 nm. As a photocatalyst, the degradation efficiencies of porous ZnO nanosheets for methyl orange (MO), methylene blue (MB) and Rhodamine B (RhB) were 97.5%, 99% and 96.8%, respectively. In addition, the degradation efficiency of ZnO for mixed dyes (Mo, MB and RhB) was satisfactory, reaching 97.7%. The photocatalytic stability of MB was further tested and remained at 99% after 20 cycles. In the experiment, ZnO/FTO (fluorine-doped tin oxide) composites were prepared by using ZnO as the conductive layer. Titanium dioxide (TiO2) was deposited on the surface of ZnO/FTO by electrodeposition, so as to obtain a TiO2/ZnO/FTO composite. By studying the electrochromic properties of this composite, it was found that the TiO2/ZnO/FTO composite shows a large light modulation range (55% at 1000 nm) and excellent cycle stability (96.6% at 200 cycles). The main reason for the excellent electrochromic properties may be the synergistic effect between the porous structure and the polymetallic oxides. This study is helpful to improve the photocatalytic efficiency and cycling stability of metal oxides, improve the transmittance of thin films and provide a new strategy for the preparation of ZnO composite materials with excellent photocatalytic and electrochromic properties.

Phyto-mediated photocatalysis: a critical review of in-depth base to reactive radical generation for erythromycin degradation

Erythromycin (ERY), designated as a risk-prioritized macrolide antibiotic on the 2015 European Union watch list, is the third most commonly used antibiotic, most likely due to its ability to inhibit the protein. ERY has revealed record-high aquatic concentrations threatening the entire ecosystem and hence demands priority remedial measures. The inefficiency of various conventional ERY degradation methodologies opened up a gateway to advanced technologies. The conventional approach comprising of a chemically formulated, single photocatalyst has a major drawback of creating multiple environmental stresses. In this context, photocatalysis is grabbing tremendous attention as an efficient and cost-effective antibiotic treatment approach. Several studies have ascertained that ZnO, TiO₂, Fe₃O₄, and rGO nanoparticles possess remarkable pollution minimizing operational capabilities. Additionally, composites are found much more effective in antibiotic removal than single nanoparticles. In this review, an attempt has been made to provide a comprehensive baseline for efficient reactive radical production by a phyto-mediated composite kept under a certain source of irradiation. Considerable efforts have been directed towards the in-depth investigation of rGO-embedded, phyto-mediated ZnO/TiO₂/Fe₃O₄ photocatalyst fabrication for efficient ERY degradation, undergoing green photocatalysis. This detailed review provides photocatalytic nanocomposite individualities along with a hypothetical ERY degradation mechanism. It is assumed that derived information presented here will provoke innovative ideas for water purification incorporating green photocatalysis, initiating the construction of high-performance biogenic hierarchical nanocatalysts.

Occurrence, toxic effects, and mitigation of pesticides as emerging environmental pollutants using robust nanomaterials - A review

Increasing demand of food and agriculture is leading us towards the increasing use and introduction of pesticides to the environment. The upright increase of pesticides in water and associated adverse effects have become a great point of concern to develop proficient methods for their mitigation from water. Various different methods have been traditionally employed for this purpose. Recently, nanotechnology has turned out to be the field of prodigious interest for this purpose, and various specific methods were developed and employed to remove pesticides from water. In this study, nanotechnological methods such as adsorption and degradation have been thoroughly discussed along with their applications and limitations where different types of nanoparticles, nanocomposites, nanotubes, and nanomembranes have played a vital role. However, in this study the most commonly adopted method of adsorption is considered to be the better technique due to its low cost, efficiency, and ease of operation. The adsorption kinetic models were described to explain the efficiency of the nano-adrsorbants in order to evaluate the mass transfer processes. However, various degradation methodologies including photocatalysis and catalytic reduction have also been elaborated. Numerous robust metal, metal oxide and functionalized magnetic nanomaterials have been emphasized, categorized, and compared for the removal of pesticides from water. Additionally, current challenges faced by researchers and future directions have also been provided.