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In this work, a simple and one-step process was demonstrated to develop hydrophobic polymer surfaces. Commercially available polycarbonate (PC) was treated to turn the front surface hydrophobic with an average wetting contact angle (WCA) as high as 110.5°. The formation of micro-flowers with a coverage density of 9.29 × 106/cm2 on the top of fine base nanostructures was confirmed by a high-resolution field emission scanning electron microscope (FESEM). Impact of typical metal and metal oxide such as silver (Ag) and tungsten oxide (WO3) deposited on such hydrophobic surfaces was demonstrated. Petals of micro-flowers and fine base nanostructures were well decorated with functional metals such as Ag and thus the front surface remained hydrophobic with an average WCA as high as 106.6°. Abundant sharp spikes on the top of narrow hills and dips as revealed in the high-resolution FESEM investigation, were speculated to be the reason behind this hydrophobic characteristic. On the other hand, the hydrophobic surface (WCA of ∼ 110.5°) turned hydrophilic (WCA of ∼11.7°) when the surface was decorated with functional metal oxides, such as WO3. Sessile drop tests were carried out to record average WCA and to understand the wetting characteristics of the specimens. A plausible mechanism for such hydrophobic characteristics as well as the transition from a hydrophobic state to a hydrophilic state has been elucidated.

This research investigates the hydrothermal synthesis and annealing duration effects on nickel sulfide (NiS2) quantum dots (QDs) for catalytic decolorization of methylene blue (MB) dye and antimicrobial efficacy. QD size increased with longer annealing, reducing catalytic activity. UV–vis, XRD, TEM, and FTIR analyses probed optical, structural, morphological, and vibrational features. XRD confirmed NiS2's anorthic structure, with crystallite size growing from 6.53 to 7.81 ​nm during extended annealing. UV–Vis exhibited a bathochromic shift, reflecting reduced band gap energy (Eg) in NiS2. TEM revealed NiS2 QD formation, with agglomerated QD average size increasing from 7.13 to 9.65 ​nm with prolonged annealing. Pure NiS2 showed significant MB decolorization (89.85%) in acidic conditions. Annealed NiS2 QDs demonstrated notable antibacterial activity, yielding a 6.15 ​mm inhibition zone against Escherichia coli (E. coli) compared to Ciprofloxacin. First-principles computations supported a robust interaction between MB and NiS2, evidenced by obtained adsorption energies. This study highlights the nuanced relationship between annealing duration, structural changes, and functional properties in NiS2 QDs, emphasizing their potential applications in catalysis and antibacterial interventions.

Abstract Presently, there is considerable emphasis on biological synthesis of nanoparticles containing bioactive reducing compounds with an aim to mitigate the harmful effects of pollutants. The approach under study is simple and ideal for the production of durable antimicrobial nanomaterials by novel single-step green synthesis of TiO2 metal oxide nanostructures using ginger and garlic crude aqueous extracts with bactericidal and catalytic activity. A variety of experimental techniques were used to characterize the synthesized nanomaterials. As demonstrated using x-ray diffraction and ultra-violet visible spectroscopy, the produced nanoparticles exhibited high absorption at 318 nm with size varying between 23.38 nm for ginger and 58.64 nm for garlic in biologically-reduced TiO2. At increasing concentrations (500, 1000 µg/50 µl), nanoparticles reduced with garlic exhibited enhanced bactericidal efficacy against multiple drug-resistant S. aureus and effectively decomposed toxic methylene blue (MB) dye. In conclusion, biologically-reduced TiO2 nanoparticles may prove an effective tool in the fight against microbial illnesses and drug resistance.

Abstract The environmental-friendly hydrothermal method has been carried out to synthesize Bi2WO6 and g-C3N4/PVP doped Bi2WO6 nanorods (NRs) by incorporating different concentrations of graphitic carbon nitride (g-C3N4) as well as a specified quantity of polyvinylpyrrolidone (PVP). Bi2WO6 doped with g-C3N4 provides structural and chemical stability, reduces charge carriers, degrades dyes, and, owing to lower bandgap energy, is effective for antibacterial, catalytic activity, and molecular docking analysis. The purpose of this research is the treatment of polluted water and to investigate the bactericidal behavior of a ternary system. The catalytic degradation was performed to remove the harmful rhodamine B (RhB) dye using NaBH4 in conjunction with prepared NRs. The specimen compound demonstrated antibacterial activity against Escherichia coli (E. coli) at both high and low concentrations. Higher doped specimens of g-C3N4/PVP-doped Bi2WO6 exhibited a significant improvement in efficient bactericidal potential against E. coli (4.55 mm inhibition zone). In silico experiments were carried out on enoyl-[acylcarrier-protein] reductase (FabI) and β-lactamase enzyme for E. coli to assess the potential of Bi2WO6, PVP doped Bi2WO6, and g-C3N4/PVP-doped Bi2WO6 NRs as their inhibitors and to justify their possible mechanism of action.

Abstract Various concentrations of samarium‐grafted‐carbon nitride (Sm‐g‐C3N4) doped‐bismuth oxobromide (BiOBr) quantum dots (QDs) are prepared by the co‐precipitation method. Elemental evaluation, morphological, optical, and functional group assessment are studied employing characterization techniques. Based on the XRD pattern analysis, it is determined that BiOBr exhibits a tetragonal crystal structure. The electronic spectroscopy revealed an absorption peak for BiOBr at 315 nm and the bandgap energy (Eg) decreasing from 3.9 to 3.8 eV with the insertion of Sm‐g‐C3N4. The presence of vibrational modes related to BiOBr at 550 cm−1 is confirmed through FTIR spectra. TEM revealed that pure BiOBr possessed non‐uniform QDS, and agglomeration increased with the addition of Sm‐g‐C3N4. The catalytic performance of Sm‐g‐C3N4 into BiOBr (6 mL) in a neutral medium toward rhodamine B exhibited excellent results (99.66%). The bactericidal activity is evaluated against multi‐drug resistance (MDR) Escherichia coli once the surface area is increased by dopant and the measured inhibition zone is assessed to be 3.65 mm. Molecular docking results supported the in vitro bactericidal potential of Sm‐g‐C3N4 and Sm‐g‐C3N4 doped‐BiOBr as DNA gyraseE. coli inhibitors. This study shows that the novel Sm‐g‐C3N4 doped‐BiOBr is a better catalyst that increases specific semiconductor's catalytic activity (CA).

In this study, MoO3 nanostructures were prepared, doped with various concentrations of graphene oxide (2 and 4% GO) and a fixed amount of polyvinylpyrrolidone (PVP) using the co-precipitation method. The motive of this study was to examine the catalytic and antimicrobial efficacy with evidential molecular docking analyses of GO/PVP-doped MoO3. GO and PVP were utilized as doping agents to reduce the exciton recombination rate of MoO3 by providing more active sites that increase the antibacterial activity of MoO3. The prepared binary dopant (GO and PVP)-dependent MoO3 was used as an effective antibacterial agent against Escherichia coli (E. coli). Notably, 4% GO/PVP-doped MoO3 showed good bactericidal potential against E. coli at higher concentrations in comparison to ciprofloxacin. Furthermore, in silico docking revealed the possible inhibitory impact of the synthesized nanocomposites on folate and fatty acid synthesis enzymes, dihydrofolate reductase and enoyl-[acyl carrier protein] reductase, respectively.

Abstract The development of efficient catalysts with a large number of active sites, tunable bandgap, and large surface area has been very challenging. In addition, a significant bottleneck in the application of catalysts for water treatment is their dissolution under extreme conditions, such as highly acidic or highly alkaline conditions that lead to poor application of the reported materials in real‐world applications. In this study, the lanthanum (La)‐doped molybdenum disulfide (MoS2) nanosheets are reported for efficient breakdown of toxic pollutants from wastewater under a wide pH range from strongly alkaline to strongly acidic solutions. The La‐MoS2 nanosheets (NSs) are prepared by a facile hydrothermal approach using a two‐step methodology. A redshift is observed upon La doping, indicating that the bandgap is lowered after La doping in MoS2. The changes in bandgap and electronic structure are further investigated using the density functional theory (DFT), which reveal that doping of La introduces new states within the bandgap region, allowing for further induced energy transitions. The La‐MoS2, having a doping concentration of 2%, exhibits the highest catalytic activity against methylene blue (MB) in neutral, acidic, and alkaline solutions, as well as substantial inhibitory activity for bacterial strains such as Escherichia coli (E. coli). In summary, the modified catalyst provides a pathway to design highly efficient catalysts for all pH range water treatment as well as good activity against microbes.

This research lays the groundwork for preparing graphene oxide (GO)-doped CaO nanocomposites for efficient antibacterial potential and dye degradation. The study aimed to reduce the recombination rate of the electron hole (e−/h+) of CaO and improve charge transfer. This issue can be minimized by doping high-surface area GO into CaO quantum dots (QDs). Herein, the one-pot co-precipitation technique has prepared various concentrations (1, 3, and 5 wt%) of GO-doped CaO. Characterization techniques were used to investigate optical, elemental analysis, microstructural, functional, and morphological properties. The addition of GO into QDs showed excellent catalytic activity (CA) to control sample CaO against methylene blue (MB) in basic and acidic media compared to the neutral media. The synergistic effect of morphological alternation attributed to an increase in the mechanism of CA upon doping. Various concentrations of GO to QDs promised remarkable bactericidal potency against Escherichia coli.

In this research work, pristine and various concentrations (2.4 wt%) of graphene oxide (GO)/carbon sphere (CS)–doped Al2O3 nanostructures (NSs) were synthesized with the chemical sol–gel method. Aluminum oxide (Al2O3) exhibits quick recombination of electrons and holes with a low specific surface to limit catalytic and antibacterial activities. Al2O3 doped with CS is good in wastewater treatment and reduces the size of NSs. The incorporation of graphene oxide (GO) into Al2O3 at different concentrations (2 and 4 wt%) enhances both the structural and chemical stabilities of the resulting material while concurrently decreasing the number of charge carriers and reducing the band gap energy. This modified Al2O3-GO composite exhibits promising potential for utilization in dye degradation and antibacterial activity. A series of characterizations were performed to investigate the structural, morphological, and optical properties. The NSs exhibited excellent catalytic activity (CA) against rhodamine B (RhB) dye in acidic, basic, and neutral media. The antimicrobial activity was tested against Escherichia coli. Pairs of electrons and holes are the primary building blocks for the production of reactive oxygen species (ROS), which causes bacteria to die. The significant inhibition zones against E. coli were calculated to be approximately 5.65 mm when compared to ciprofloxacin. Moreover, in silico investigations have revealed the possible inhibitory impact of produced nanomaterials (GO/CS-doped Al2O3) on DNA gyrase and FabI enzymes of fatty acid biosynthesis.

The emergence of multi-drug resistance (MDR) in aquatic pathogens and the presence of cationic dyes are the leading causes of water contamination on a global scale. In this context, nanotechnology holds immense promise for utilizing various nanomaterials with catalytic and antibacterial properties. This study aimed to evaluate the catalytic and bactericidal potential of undoped and Sr-doped Cr2O3 nanostructures (NSs) synthesized through the co-precipitation method. In addition, the morphological, optical, and structural properties of the resultant NSs were also examined. The optical bandgap energy of Cr2O3 has been substantially reduced by Sr doping, as confirmed through extracted values from absorption spectra recorded by UV-Vis studies. The field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) micrographs illustrate that the composition of Cr2O3 primarily consisted of agglomerated, irregularly shaped NSs with a morphology resembling nanoflakes. Moreover, the presence of Sr in the lattice of Cr2O3 increased the roughness of the resulting NSs. The catalytic activity of synthesized NSs was analyzed by their reduction ability of Rhodamine B (RhB) dye in the dark under different pH conditions. Their antibacterial activity was evaluated against MDR Escherichia coli (E. coli). Sr doping increased antibacterial efficiency against MDR E. coli, as indicated by inhibition zone measurements of 10.15 and 11.75 mm at low and high doses, respectively. Furthermore, a molecular docking analysis was conducted to determine the binding interaction pattern between NSs and active sites in the target cell protein. The findings corroborated antimicrobial test results indicating that Sr-Cr2O3 is the most effective inhibitor of FabH and DHFR enzymes.

Abstract Nitrides, carbides, and carbonitrides of transition metal elements like Zr, W, Ti, etc. are generally employed to produce hard coatings. Zirconium-based hard coatings have shown useful applications in the areas of tribology, biomedicine and electrical due to their high thermal stability, hardness, biocompatibility, good erosion, wear, and corrosion resistance. In this study, we created homogeneous and tenacious nanostructured hard coatings based on Zr with good mechanical properties. The magnetron sputter deposition technique was utilized to coat stainless steel 316L substrates with multilayers of Zr/ZrN and ZrN/ZrCN with individual layer thicknesses of 250 and 500 nm for each coating composition. The deposition conditions were adjusted to create two different coating thicknesses of 2 and 3 µm. The thickness of the coating was confirmed using Calotest and the coatings’ morphology and elemental composition were determined utilizing the atomic force microscope and scanning electron microscope equipped with energy dispersive x-ray spectrometer. Coating thickness and adhesion were measured using cross-sectional samples and XRD was utilized to analyze the coatings structure. Nanoindenter was employed to determine the instrumental nanoindentation hardness and elastic modulus. The influence of coating thickness on tribological behavior was further investigated using the ratio of nanohardness-to-elastic modulus (H/E). No evidence of decohesion was observed at the substrate/coatings interface, and the grains of all the coatings were observed to show columnar growth which were homogeneous, compact and dense. The grains of the ZrN/ZrCN coatings were observed to be denser, finer and more compact compared to those of the Zr/ZrN coatings. Correspondingly, higher hardness, modulus and H/E values were exhibited by ZrN/ZrCN than Zr/ZrN coatings. This suggests that the ZrN/ZrCN coatings are capable of exhibiting better wear resistance and fracture toughness. The coatings developed in this investigation are anticipated to be suitable for applications in tribology due to their excellent hardness and H/E properties.

Three-dimensional printing (3DP), known as additive layer manufacturing (ALM), is a manufacturing process in which a three-dimensional structure is constructed by successive addition of deposited layers. Fused Deposition Modeling (FDM) has evolved as the most frequently utilized ALM process because of its cost-effectiveness and ease of operation. Nevertheless, layer adhesion, delamination, and quality of the finished product remain issues associated with the FDM process parameters. These issues need to be addressed in order to satisfy the requirements commonly imposed by the conventional manufacturing industry. This work is focused on the optimization of the FDM process and post-process parameters for Polylactic acid (PLA) samples in an effort to maximize their tensile strength. Infill density and pattern type, layer height, and print temperature are the process parameters, while annealing temperature is the post-process parameter considered for the investigation. Analysis based on the Taguchi L18 orthogonal array shows that the gyroid infill pattern and annealing cycle at 90 °C results in a maximum ultimate tensile strength (UTM) of 37.15 MPa. Furthermore, the regression model developed for the five variables under study was able to predict the UTS with an accuracy of more than 96%.

In this study, poly(isobutylene-alt-maleic anhydride) (PMA)-coated spinel ferrite (MFe2O4, where M = Fe, Co, Ni, or Zn) nanoparticles (NPs) were developed as carriers of the anticancer drugs doxorubicin (DOX) and methotrexate (MTX). Physical characterizations confirmed the formation of pure cubic structures (14–22 nm) with magnetic properties. Drug-loaded NPs exhibited tumor specificity with significantly higher (p < 0.005) drug release in an acidic environment (pH 5.5). The nanoparticles were highly colloidal (zeta potential = −35 to −26 mV) in deionized water, phosphate buffer saline (PBS), and sodium borate buffer (SBB). They showed elevated and dose-dependent cytotoxicity in vitro compared to free drug controls. The IC50 values ranged from 0.81 to 3.97 μg/mL for HepG2 and HT144 cells, whereas IC50 values for normal lymphocytes were 10 to 35 times higher (18.35–43.04 µg/mL). Cobalt ferrite (CFO) and zinc ferrite (ZFO) NPs were highly genotoxic (p < 0.05) in cancer cell lines. The nanoparticles caused cytotoxicity via oxidative stress, causing DNA damage and activation of p53-mediated cell cycle arrest (significantly elevated expression, p < 0.005, majorly G1 and G2/M arrest) and apoptosis. Cytotoxicity testing in 3D spheroids showed significant (p < 0.05) reduction in spheroid diameter and up to 74 ± 8.9% of cell death after two weeks. In addition, they also inhibited multidrug resistance (MDR) pump activity in both cell lines suggesting effectivity in MDR cancers. Among the tested MFe2O4 NPs, CFO nanocarriers were the most favorable for targeted cancer therapy due to excellent magnetic, colloidal, cytotoxic, and biocompatible aspects. However, detailed mechanistic, in vivo cytotoxicity, and magnetic-field-assisted studies are required to fully exploit these nanocarriers in therapeutic applications.

Abstract The development of resistance against antibiotics used to treat bacterial infections along with the prevalence of medication residues presents significant public health problems globally. Antibiotic-resistant germs result in infections that are difficult or impossible to treat. Decreasing antibiotic effectiveness calls for rapid development of alternative antimicrobials. In this respect, nanoparticles (NPs) of copper oxide (CuO) manifest a latent and flexible inorganic nanostructure with noteworthy antimicrobial impact. Green synthesis of CuO NPs was performed in the current study, which was then doped with varying amounts of ginger (Zingiber officinale, ZO) and garlic (Allium sativum, AS) extracts. In low and high doses, the synthesized compound was used to measure the antimicrobial effectiveness against pathogenic Escherichia coli. The present research successfully demonstrated a renewable, eco-friendly synthesis technique with natural materials that is equally applicable to other green metal oxide NPs.

Abstract Nitrogen (N) and carbon nitride (C3N4)-doped TiO2 nanostructures were prepared using co-precipitation route. Fixed amount of N and various concentrations (0.1, 0.2, 0.3 wt%) of C3N4 were doped in TiO2 lattice. Through multiple techniques, structural, chemical, optical and morphological properties of samples were thoroughly investigated. XRD results verified anatase TiO2 presence along the substitutional doping of N, while higher degree of crystallinity as well as increased crystallite size were noticed after doping. HR-TEM study revealed formation of nanostructures incorporated on two dimensional (2D) C3N4 nanosheet surface. Elemental composition was checked out using EDS technique which confirmed the presence of dopant in product. Optical characteristics were evaluated with UV–vis spectroscopy which depicted representative redshift in absorption spectra resulted in a reduction in bandgap energy in N/C3N4-doped TiO2 samples. The formation of Ti–O–Ti bonds and different molecular vibrations were disclosed by FTIR. Trap sites and charge carrier’s migration in the materials were evaluated with PL spectroscopy. Multiple catalytic activities (photo, sono and photo-sono) were undertaken to evaluate the dye degradation performance of prepared specimen against methylene blue and ciprofloxacin. Further, antimicrobial activity was analyzed against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria.

Abstract Various concentrations of Mg-doped ZnO nanorods (NRs) were prepared using co-precipitation technique. The objective of this study was to improve the photocatalytic properties of ZnO. The effect of Mg doping on the structure, phase constitution, functional groups presence, optical properties, elemental composition, surface morphology and microstructure of ZnO was evaluated with XRD, FTIR, UV–Vis spectrophotometer, EDS, and HR-TEM, respectively. Optical absorption spectra obtained from the prepared samples showed evidence of blueshift upon doping. XRD results revealed hexagonal wurtzite phase of nanocomposite with a gradual decrease in crystallite size with Mg addition. PL spectroscopy showed trapping efficiency and migration of charge carriers with electron–hole recombination behavior, while HR-TEM estimated interlayer d-spacing. The presence of chemical bonding, vibration modes and functional groups at the interface of ZnO was revealed by FTIR and Raman spectra. In this study, photocatalytic, sonocatalytic and sonophotocatalytic performance of prepared NRs was systematically investigated by degrading a mixture of methylene blue and ciprofloxacin (MBCF). Experimental results suggested that improved degradation performance was shown by Mg-doped ZnO NRs. We believe that the product synthesized in this study will prove to be a beneficial and promising photocatalyst for wastewater treatment. Conclusively, Mg-doped ZnO exhibited substantial (p

Abstract In the present work, boron nitride (BN) nanosheets were prepared through bulk BN liquid phase exfoliation while various wt. ratios (2.5, 5, 7.5 and 10) of bismuth (Bi) were incorporated as dopant using hydrothermal technique. Our findings exhibit that the optical investigation showed absorption spectra in near UV region. Density functional theory calculations indicate that Bi doping has led to various modifications in the electronic structures of BN nanosheet by inducing new localized gap states around the Fermi level. It was found that bandgap energy decrease with the increase of Bi dopant concentrations. Therefore, in analysis of the calculated absorption spectra, a redshift has been observed in the absorption edges, which is consistent with the experimental observation. Additionally, host and Bi-doped BN nanosheets were assessed for their catalytic and antibacterial potential. Catalytic activity of doped free and doped BN nanosheets was evaluated by assessing their performance in dye reduction/degradation process. Bactericidal activity of Bi-doped BN nanosheets resulted in enhanced efficiency measured at 0–33.8% and 43.4–60% against S. aureus and 0–38.8% and 50.5–85.8% against E. coli, respectively. Furthermore, In silico molecular docking predictions were in good agreement with in-vitro bactericidal activity. Bi-doped BN nanosheets showed good binding score against DHFR of E. coli (− 11.971 kcal/mol) and S. aureus (− 8.526 kcal/mol) while binding score for DNA gyrase from E. coli (− 6.782 kcal/mol) and S. aureus (− 7.819 kcal/mol) suggested these selected enzymes as possible target.

Abstract The present study is concerned with evaluating the influence of various concentrations of Ag within Cu:Ag bimetallic nanoparticles developed for use as a promising anti-bacterial agent against antibiotic-resistant bacteria. Here, Cu:Ag bimetallic nanoparticles with various concentration ratios (2.5, 5.0, 7.5, and 10 wt%) of Ag in fixed amount of Cu labeled as 1:0.025, 1:0.050, 1:0.075, and 1:0.1 were synthesized using co-precipitation method with ammonium hydroxide and deionized water as solvent, polyvinyl pyrrolidone as a capping agent, and sodium borohydride and ascorbic acid as reducing agents. These formulated products were characterized through a variety of techniques. XRD confirmed phase purity and detected the presence of distinct fcc structures belonging to Cu and Ag phases. FTIR spectroscopy confirmed the presence of vibrational modes corresponding to various functional groups and recorded characteristic peak emanating from the bimetallic. UV–visible spectroscopy revealed reduction in band gap with increasing Ag content. SEM and HR-TEM micrographs revealed spherical morphology of Ag-doped Cu bimetallic with small and large scale agglomerations. The samples exhibited varying dimensions and interlayer spacing. Bactericidal action of synthesized Cu:Ag bimetallic NPs depicted statistically significant (P

Introduction: Hard coatings are primarily based on carbides, nitrides and carbonitrides of transition metal elements such as W, Ti, Zr, etc. Zr-based hard coatings show good resistance to wear, erosion, and corrosion as well as exhibit high hardness, high temperature stability, and biocompatibility, making them suitable candidates for tribological, biomedical, and electrical applications. Objectives: The present study aims to synthesize uniform and adherent hard Zr-based coatings that demonstrate sound mechanical integrity. Methods: Stainless steel (SS316) samples were coated with single layers of Zr, Zr-nitride, and Zr-carbonitride using magnetron sputter deposition technique. Deposition conditions were controlled to produce each coating with two different thickness i.e., 2 and 3 μm. Calotest was employed to confirm coatings thickness. Scanning electron microscope fitted with energy dispersive x-ray spectrometer was used to ascertain the morphology and elemental constitution of coatings. Cross-sectional samples were examined to ascertain coatings thickness and adhesion. X-ray diffractometer was employed for structural analysis. Instrumented nanoindentation hardness and elastic modulus were determined with nanoindenter. Ratio of nanohardness to elastic modulus was evaluated to observe the effect of coatings thickness on tribological behavior. Results: Three coating compositions were produced namely hcp-Zr, fcc-ZrN and fcc-Zr2CN. The highest hardness and elastic modulus were shown by ZrN coatings while pure Zr coatings showed the lowest values. Conclusion: All coating compositions were found to be relatively uniform, continuous and adherent with no evidence of decohesion at the coating-substrate interface. Coatings produced in this study are thought to be suitable for tribological applications.

Abstract Nanosized tin oxide was fabricated with a simple and cost-effective precipitation technique and was analyzed by performing x-ray powder diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, high-resolution transmission electron (HR-TEM) microscopy, energy-dispersive x-ray (EDX) and UV–Vis spectroscopy. The XRD results revealed that tin oxide particles possessed typical orthorhombic structure and exhibited improved crystallinity with annealing. Calcination at 250 °C produced predominantly orthorhombic SnO which transformed to SnO2 at higher temperatures of 500 and 750 °C. HRTEM and FESEM images showed existence of agglomeration within the particles of tin oxide. The absorption was found to increase up to a certain annealing temperature followed by a decrease, which was recorded via UV–Vis spectroscopy. The effect of annealing temperature on dye decomposition behavior of synthesized photocatalysts was studied. It was noted that annealing temperature affects the size of synthesized particles, band gap width and photoactivity of tin oxide. The sample prepared at 500 °C followed first-order kinetics and exhibited maximum photocatalytic reactivity toward methylene blue. The experimental results obtained from the present study indicate that SnO2 is a promising and beneficial catalyst to remove contaminants from wastewater and environment. The antimicrobial evaluation of SnO annealed at 500 °C against selected targets such as E. coli and S. aureus depicted significant inhibition zones in comparison with 250 and 750 °C samples. Furthermore, molecular docking predictions of SnO2 nanoparticles (NPs) were performed against active pocket of β-lactamase and DNA gyrase enzyme belonging to cell wall and nucleic acid biosynthetic pathway, respectively. The fabricated NPs showed good binding score against β-lactamase of both E. coli (− 5.71 kcal/mol) and S. aureus (− 11.83 kcal/mol) alongside DNA gyrase (− 9.57 kcal/mol; E. coli and − 8.61 kcal/mol; S. aureus). These in silico predictions suggested SnO2 NPs as potential inhibitors for selected protein targets and will facilitate to have a clear understanding of their mechanism of action that may contribute toward new antibiotics discovery.

In this research, bimetallic nickel-zirconia supported on mesoporous nanoparticles (Ni-Zr/MSN) were successfully synthesized by a simple in situ electrolysis method. Ni-Zr/MSN were well-characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) analyzer, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Ni-Zr/MSN were then cast onto a modified glassy carbon electrode (Ni-Zr/MSN/GCE) as dopamine (DA) sensor. Under optimal conditions, the sensor showed a linear concen­tration relationship in the range of 0.3 µM–0.1 mM with a limit of detection of 0.13 µM. The relative standard deviation for 0.1 mM DA solution was 2.1 % (n = 5). The presence of excess catechol, saccharose, glycine, lactose, uric acid, and Cr3+, Fe2+ and Na+ as interferents was negligible, except for uric acid in 10-fold excess. The analytical recovery of the sensor was successfully demonstrated by the determination of DA in DA-containing medicine and wastewater samples. The results presented herein provide new perspectives on Ni-Zr/MSN as a potential nanomaterial in the development of DA sensors.

Abstract Graphene oxide (GO) was obtained through modified hummers method, and reduced graphene oxide (rGO) was acquired by employing heat treatment. Various concentrations (2.5, 5, 7.5, and 10 wt. %) of silver (Ag) were incorporated in GO nanosheets by adopting hydrothermal approach. Synthesized Ag decorated rGO photocatalyst Ag/rGO was characterized using X-ray diffraction (XRD) to determine phase purity and crystal structure. XRD patterns showed the formation of GO to Ag/rGO. Molecular vibration and functional groups were determined through Fourier Transform Infrared spectroscopy (FTIR). Optical properties and a decrease in bandgap with insertion of Ag were confirmed with UV-Visible (Uv-Vis) spectrophotometer and photoluminescence (PL). Electronic properties and disorders in carbon structures were investigated through Raman spectroscopy that revealed the existence of characteristic bands (D and G). Surface morphology of prepared samples was examined with field emission scanning electron microscope (FESEM). Homogeneous distribution, size, and spherical shape of Ag NPs over rGO sheets were further confirmed with the help of high-resolution transmission electron microscope (HR-TEM). Dye degradation of doped and undoped samples was examined through Uv-Vis spectra. Experimental results indicated that photocatalytic activity of Ag@rGO enhanced with increased doping ratio owing to diminished electron-hole pair recombination. Therefore, it is suggested that Ag@rGO can be used as a beneficial and superior photocatalyst to clean environment and wastewater.

This study proposes durable concrete mix design suitable for use in superstructures of an industrial plant of a cement company located in an area marked by heavy industrial pollution. Concentration of pollutants in the environment was recorded by undertaking ambient air quality monitoring along with an assessment of corrosivity of soil and ground water present at the site. Type of reinforcement, concreting procedures and protection methods were determined for reinforced concrete that was intended to be used in conjunction with steel structures. Experimental results indicated that soil and groundwater constituted no risk for the substructure. However, air was highly polluted and deemed to be severely corrosive due to the presence of chloride and sulfate salts, SO2 and CO2 in concentrations recorded several times higher than at a comparable industrial area. A concrete mix design suitable for observed conditions was recommended. Additionally, it was suggested that concrete reinforced with black steel bars should be completely coated while that using FBE coated steel bars should be coated up to a height of 1.5m from the grade level for protection against ingress of salt and water.

Abstract Dopamine (DA) is a neurotransmitter that plays a pivotal role in the brain's proper functioning and several other physiological processes. Herein, we demonstrate the miniaturized electrochemical sensor for detecting DA using hafnium metal‐organic framework (Hf‐MOF) derived new nanocomposite of hafnium and cobalt oxides (HfO2‐CoO). Calcination of Hf‐MOF coated with cobalt acetylacetonate complex [(Co(acac)2] yield HfO2‐CoO nanoparticles supported over in situ generated graphitic carbon. The excellent adsorption capabilities of HfO2 and highly catalytic CoO activity make this bimetallic HfO2‐CoO nanocomposite to display a stable response over a wide linear concentration range when used as electrode material in the electrochemical DA sensing process. Moreover, the computational study also proves that CoO improves the chemisorption properties of HfO2 for DA. Electrochemical studies are performed through cyclic voltammetry (CV), linear sweep voltammetry (LSV), and differential pulse voltammetry (DPV). For the case of LSV, the HfO2‐CoO nanocomposite modified glassy carbon electrode (HfO2‐CoO/GCE) exhibit a linear response to DA concentration ranging from 0.25 to 3.15 mM. However, with DPV HfO2‐CoO/GCE electrode has displayed a linear range of 10–190 μM and a detection limit of 1.8 μM is achieved. The electrode has also shown excellent stability, and only 19 % loss in its initial current response is observed over 150 days of specific interval testing. The HfO2‐CoO/GCE nanocomposite electrode, due to its unique feature of stability, selectivity, and sensitivity, has a good potential for use as an analytical tool for non‐enzymatic sensing of DA and other neurotransmitters in the human fluid.

An electrochemical chemical sensor for determination of uric acid (UA) with highly sensitive and widely working range was fabricated using zinc layered hydroxide-sodium dodecyl sulphate-propoxur (ZLH-SDS-PRO) nanocomposites modified with multiwall carbon nanotubes (MWCNT). Introduction of the ZLH-SDS-PRO as a conducting matrix has enhanced the conductivity of MWCNT. The ZLH-SDS-PRO/MWCNT morphology was characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), meanwhile the electrochemical behaviour of UA and K3[Fe(CN)6] at ZLH-SDS-PRO/MWCNT paste electrode was studied by square wave voltammetry (SWV) and cyclic voltammetry (CV), respectively. Under the optimized experimental conditions, the electrode established linear plot for UA from 7.0 µmol/L to 0.7 mmol/L (R2 = 0.9920) and the LOD was calculated to be 4.28 µmol/L (S/N = 3). The fabricated electrochemical electrode was successfully applied to urine samples and exhibit excellent stability and reproducibility, which made it worthwhile to be explored for analytical applications.

The current study enumerates the use of supported liquid membrane (SLM) technology to remove and recover crystal violet dye from wastewaters. The management of textile industry waste effluents is one of the main concerns of environmental health experts due to having excessive concentrations of dyes and resistance to biodegradation. Liquid membranes offer an affordable and green method for the selective removal of dyes from aqueous solutions. To create a liquid membrane, refined and edible vegetable oils were supported on microporous polymeric films of polypropylene (PP1E). Various parameters influencing transport, such as pH range in the feed solution, initial dye concentration, acid concentration in the strip solution, oil viscosities, and membrane lifetime, have been studied. The maximum flux value (1.7×10−5 mg/cm2/s) for crystal violet dye was obtained with sunflower oil-supported membrane at a pH of 12 in the feed solution and a concentration of 0.3 M hydrochloric acid in the strip solution. Under ideal conditions, the maximum amount of dye was transported within 6 hours. Studies on membrane stability and morphology revealed that the flux remained constant up to about 24 hours and then decreased gradually. Morphological studies showed that this may be attributed to deformation of pores shape and gradual clogging.

Fabrication of stable and efficient zerovalent non-noble metal-based nanostructured catalyst has emerged as the hot area of research for wastewater treatment due to their low cost and facile natural source availability. In this work, the rationally controlled calcination of iron-terephthalate MOF has produced the magnetically active zero-valent iron-based nanostructured catalyst. Unlike other synthesis approaches, MOF’s temperature-controlled calcination has offered highly effective and stable metallic iron nanoparticles encapsulated in few-layered porous graphitic carbons. The developed nanostructured catalyst was applied for room temperature conversion of hazardous 4-Nitrophenol (4-NiP) to a value-added industrial intermediate 4-Aminophenol (4-AP) by exploiting sodium borohydride as a hydrogen donor agent. The synthesized zerovalent iron-based nanostructured catalysts were thoroughly investigated and characterized by powder X-ray diffraction (pXRD), infrared and Raman spectroscopy, thermogravimetric analysis (TGA), energy dispersive X-Rays (EDS), X-ray photoelectron (XPS) spectroscopy, and transmission electron microscopy (TEM). The UV–Vis spectroscopy was used for the monitoring of the conversion of the 4-NiP into 4-AP. The conversion analysis result has shown that the MOF-based precursors’ calcination temperature has played a critical role in the potency of the catalyst for converting the 4-NiP into 4-AP. The outer porous architecture provided the facile adsorption and desorption of the 4-NiP on the active nanostructured metallic iron catalyst. The maximum degradation of 4-NiP into 4-AP has taken place in a short time of 3 ​min at a rate constant of 0.0149 s−1. In terms of economic perspective and high catalytic efficiency, the developed low coast nanostructured catalyst is the right choice over the reported noble metal-based catalyst for the room temperature conversion of 4NiP to a value-added product.

This article describes the design and synthesis of a series of novel amantadine-thiourea conjugates (3a–j) as Jack bean urease inhibitors. The synthesized hybrids were assayed for their in vitro urease inhibition. Accordingly, N-(adamantan-1-ylcarbamothioyl)octanamide (3j) possessing a 7-carbon alkyl chain showed excellent activity with IC50 value 0.0085 ± 0.0011 µM indicating that the long alkyl chain plays a vital role in enzyme inhibition. Whilst N-(adamantan-1-ylcarbamothioyl)-2-chlorobenzamide (3g) possessing a 2-chlorophenyl substitution was the next most efficient compound belonging to the aryl series with IC50 value of 0.0087 ± 0.001 µM. The kinetic mechanism analyzed by Lineweaver–Burk plots revealed the non-competitive mode of inhibition for compound 3j. Moreover, in silico molecular docking against target protein (PDBID 4H9M) indicated that most of the synthesized compounds exhibit good binding affinity with protein. The compound 3j forms two hydrogen bonds with amino acid residue VAL391 having a binding distance of 1.858 Å and 2.240 Å. The interaction of 3j with amino acid residue located outside the catalytic site showed its non-competitive mode of inhibition. Based upon these results, it is anticipated that compound 3j may serve as a lead structure for the design of more potent urease inhibitors.

Thermoplastic starch (TPS) hybrid bio-composite films containing microcrystalline cellulose (C) and nano-bentonite (B) as hybrid fillers were studied to replace the conventional non-degradable plastic in packaging applications. Raw oil palm empty fruit bunch (OPEFB) was subjected to chemical treatment and acid hydrolysis to obtain C filler. B filler was ultra-sonicated for better dispersion in the TPS films to improve the filler–matrix interactions. The morphology and structure of fillers were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). TPS hybrid bio-composite films were produced by the casting method with different ratios of B and C fillers. The best ratio of B/C was determined through the data of the tensile test. FTIR analysis proved the molecular interactions between the TPS and the hybrid fillers due to the presence of polar groups in their structure. XRD analysis confirmed the intercalation of the TPS chains between the B inter-platelets as a result of well-developed interactions between the TPS and hybrid fillers. SEM images suggested that more plastic deformation occurred in the fractured surface of the TPS hybrid bio-composite film due to the higher degree of stretching after being subjected to tensile loading. Overall, the results indicate that incorporating the hybrid B/C fillers could tremendously improve the mechanical properties of the films. The best ratio of B/C in the TPS was found to be 4:1, in which the tensile strength (8.52MPa), Young’s modulus (42.0 MPa), elongation at break (116.4%) and tensile toughness of the film were increased by 92%, 146%, 156% and 338%, respectively. The significantly improved strength, modulus, flexibility and toughness of the film indicate the benefits of using the hybrid fillers, since these features are useful for the development of sustainable flexible packaging film.

A photocatalytic system for decolorization of double azo reactive black 5 (RB5) dye and water disinfection of E. coli was developed. Sol gel method was employed for the synthesis of Fe-TiO2 photocatalysts and were characterized using thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS) and Brunauer–Emmett–Teller (BET) analysis. Results showed that photocatalytic efficiency was greatly influenced by 0.1 weight percent iron loading and 300 °C calcination temperature. The optimized reaction parameters were found to be the ambient temperature, working solution pH 6.2 and 1 mg g−1 dose to completely decolorize RB5. The isotherm studies showed that RB5 adsorption by Fe-TiO2 followed the Langmuir isotherm with maximum adsorption capacity of 42.7 mg g−1 and Kads 0.0079 L mg−1. Under illumination, the modified photocatalytic material had higher decolorization efficiency as compared to unmodified photocatalyst. Kinetic studies of the modified material under visible light irradiation indicated the reaction followed the pseudo-first-order kinetics. The illumination reaction followed the Langmuir-Hinshelwood (L-H) model as the rate of dye decolorization increased with an incremental increase in dye concentration. The L-H constant Kc was 1.5542 mg L–1∙h–1 while Kads was found 0.1317 L mg–1. The best photocatalyst showed prominent percent reduction of E. coli in 120 min. Finally, 0.1Fe-TiO2-300 could be an efficient photocatalyst and can provide a composite solution for RB5 decolorization and bacterial strain inhibition.

In this work, dolomite filler was introduced into thermoplastic starch (TPS) matrix to form TPS-dolomite (TPS-DOL) biocomposites. TPS-DOL biocomposites were prepared at different dolomite loadings (1 wt%, 2 wt%, 3 wt%, 4 wt% and 5 wt%) and by using two different forms of dolomite (pristine (DOL(P) and sonicated dolomite (DOL(U)) via the solvent casting technique. The effects of dolomite loading and sonication process on the mechanical properties of the TPS-DOL biocomposites were analyzed using tensile and tear tests. The chemistry aspect of the TPS-DOL biocomposites was analyzed using Fourier transform infrared spectroscopy (FTIR) and X-Ray Diffraction (XRD) analysis. According to the mechanical data, biocomposites with a high loading of dolomite (4 and 5 wt%) possess greater tensile and tear properties as compared to the biocomposites with a low loading of dolomite (1 and 2 wt%). Furthermore, it is also proved that the TPS-DOL(U) biocomposites have better mechanical properties when compared to the TPS-DOL(P) biocomposites. Reduction in the dolomite particle size upon the sonication process assisted in its dispersion and distribution throughout the TPS matrix. Thus, this led to the improvement of the tensile and tear properties of the biocomposite. Based on the findings, it is proven that the sonication process is a simple yet beneficial technique in the production of the TPS-dolomite biocomposites with improved tensile and tear properties for use as packaging film.

Transparent and amorphous yttrium (Y)/Sialon thin films were successfully fabricated using pulsed laser deposition (PLD). The thin films were fabricated in three steps. First, Y/Sialon target was synthesized using spark plasma sintering technique at 1500 °C in an inert atmosphere. Second, the surface of the fabricated target was cleaned by grinding and polishing to remove any contamination, such as graphite and characterized. Finally, thin films were grown using PLD in an inert atmosphere at various substrate temperatures (RT to 500 °C). While the X-ray diffractometer (XRD) analysis revealed that the Y/Sialon target has β phase, the XRD of the fabricated films showed no diffraction peaks and thus confirming the amorphous nature of fabricated thin films. XRD analysis displayed that the fabricated thin films were amorphous while the transparency, measured by UV-vis spectroscopy, of the films, decreased with increasing substrate temperature, which was attributed to a change in film thickness with deposition temperature. X-ray photoelectron spectroscopy (XPS) results suggested that the synthesized Y/Sialon thin films are nearly homogenous and contained all target’s elements. A scratch test revealed that both 300 and 500 °C coatings possess the tough and robust nature of the film, which can resist much harsh loads and shocks. These results pave the way to fabricate different Sialon doped materials for numerous applications.

Plain carbon steel substrates were treated with NaH2PO4.H2O inhibitor for 24 hours and coated with Ni using dc and pulse electrodeposition in standard Watt’s bath. The effect of dc and pulse electrodeposition, on the microstructure and corrosion properties of Ni coatings in 3.5 wt% NaCl solution was studied. The effect of inhibitor on the deposition process and corrosion behavior was also examined. Materials characterization was performed using field emission scanning electron microscopy, cross-sectional scanning transmission electron microscopy, atomic force microscopy, x-ray diffraction and nanoindentation. Experimental results indicated that pulse electrodeposition produced fine grained Ni coatings that showed lower corrosion rate compared to coarse grained dc electrodeposited Ni. Pre-treatment of substrates with inhibitor did not adversely affect the deposition process and adherent Ni coatings were readily developed. The results showed that pulse electrodeposition could be used to produce hard corrosion resistant Ni coatings while the inhibitor treatment yielded enhanced corrosion protection by providing a protective buffer layer between the Ni coating and the substrate.