Efficient template based synthesis of Ni nanorods by etching porous alumina for their enhanced photocatalytic activities against Methyl Red and Methyl Orange dyes

A critical review on application of organic, inorganic and hybrid nanophotocatalytic assemblies for photocatalysis of methyl orange dye in aqueous medium

Methyl orange (MO) is a highly carcinogenic and harmful contaminant, which has been extensively reported for its detrimental impact on human and aquatic life. The photodegradation of MO into less toxic products has gained much attention over the past few decades. Herein we have reviewed the recent advancement in designing of nanomaterials (NMs) stabilized on different fabricating assemblies and their application in photocatalysis of MO dye. These photocatalytic systems possess various advantages and disadvantages. Graphene-based supported materials on different NMs are highly reported photocatalysts for photocatalysis of MO dye. Recent advancement, parameters affecting photocatalytic studies, kinetics and photocatalytic mechanism of MO have been thoroughly explained in this review. Future outcomes are also provided for extending the development of scientific research in this field.

Application of visible light active photocatalysis for water contaminants: A review

Organic water pollutants are ubiquitous in the natural environment arising from domestic products as well as current and legacy industrial processes. Many of these organic water pollutants are recalcitrant and only partially degraded using conventional water and wastewater treatment processes. In recent decades, visible light active photocatalyst has gained attention as a non-conventional alternative for the removal of organic pollutants during water treatment, including industrial wastewater and drinking water treatment. This paper reviews the current state of research on the use of visible light active photocatalysts, their modified methods, efficacy, and pilot-scale applications for the degradation of organic pollutants in water supplies and waste streams. Initially, the general mechanism of the visible light active photocatalyst is evaluated, followed by an overview of the major synthesis techniques. Because few of these photocatalysts are commercialized, particular attention was given to summarizing the different types of visible light active photocatalysts developed to the pilot-scale stage for practical application and commercialization. The organic pollutant degradation ability of these visible light active photocatalysts was found to be considerable and in many cases comparable with existing and commercially available advanced oxidation processes. Finally, this review concludes with a summary of current achievements and challenges as well as possible directions for further research. PRACTITIONER POINTS: Visible light active photocatalysis is a promising advanced oxidation process (AOP) for the reduction of organic water pollutants. Various mechanisms of photocatalysis using visible light active materials are identified and discussed. Many recent photocatalysts are synthesized from renewable materials that are more sustainable for applications in the 21st century. Only a small number of pilot-scale applications exist and these are outlined in this review.

UV-irradiating synthesis of cyclodextrin–silver nanocluster decorated TiO2 nanoparticles for photocatalytic enhanced anticancer effect on HeLa cancer cells

Titanium dioxide (TiO₂) has emerged as a viable choice for several biological and environmental applications because of its high efficiency, cheap cost, and high photostability. In pursuit of this purpose, the research of its many forms has been influenced by these unique aspects. The development of novel TiO₂-based hybrid materials with enhanced photocatalytically induced anticancer activity has gained tremendous attention. Here, we have developed a novel photocatalytic material (TiO₂–Ag NPs@-CD) by decorating ultrasmall silver nanoparticles (Ag NPs) with per-6-thio-β-cyclodextrin (SH-β-CD) on TiO₂ NPs. TiO₂–Ag NPs@-CD were characterized by employing various characterization techniques and evaluated for their anticancer activity against HeLa cancer cells using an MTT assay. The biocompatibility of the designed nanoparticles was determined on two normal cell lines, namely, 3T3 and human mesenchymal stem cells (hMSCs). The results show that the TiO₂–Ag NPs@-CD induced superior cytotoxic effects on HeLa cancer cells at a concentration of 64 μg/ml. Live-dead staining and oxidative stress investigations demonstrated that cell membrane disintegration and ROS-induced oxidative stress generated by TiO₂-Ag NPs@-CD inside HeLa cancer cells are the contributing factors to their exceptional anti-cancer performance. Moreover, TiO₂-Ag NPs@-CD exhibited good biocompatibility with 3T3 and hMSCs. These results indicated that the combination of all three components—a silver core, SH-β-CD ligands, and TiO₂ nanoparticles—produced a synergistic anticancer effect. Hence, the TiO₂-Ag NPs@-CD is a promising material that can be employed for different biological applications.

Effective Removal of Methylene Blue by Surface Alteration of TiO2 with Ficus Carica Leaf Extract under Visible Light

The present study describes the use of a leaf extract from Ficus carica as a source of natural antioxidants for the surface alteration of bulk titanium dioxide (TiO₂) in two steps. First, the hydro-thermal treatment of the bulk TiO₂ material was carried out and followed by thermal annealing at 300 °C for 3 h in air. The role of the leaf extract of Ficus carica on the performance of the bulk TiO₂ material for the removal of methylene blue (MB) was also studied. Various analytical techniques such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) were used to explore the crystalline structure, morphology, and composition. The bulk TiO₂ material after the leaf-extract treatment exhibited mixed anatase and rutile phases, a flower-like morphology, and Ti, O, and C were its main elements. The average crystallite size was also calculated, and the obtained values for the bulk TiO₂ material, 18.11 nm, and the treated bulk TiO₂ material with various amounts, 5, 10, and 15 mL, of leaf extract were 16.4, 13.16, and 10.29 nm respectively. Moreover, Fourier-transform infrared spectroscopy validated the typical metal-oxygen bonds and strengthened the XRD results. The bulk TiO₂ material chemically treated with Ficus carica has shown outstanding activity towards the degradation of MB under sunlight. The 15 mL of Ficus carica extract significantly enhanced the photocatalytic activity of the bulk TiO₂ material towards the degradation of MB. The dye degradation efficiency was found to be 98.8%, which was experimentally proven by the Fourier Transform Infrared spectroscopoyy (FTIR) analysis. The obtained performance of the bulk TiO₂ material with Ficus carica revealed excellent surface modifying properties for poorly-performing photocatalysts towards the degradation of synthetic dyes when used in their pristine form. The presented approach suggests that Ficus carica could be of great interest for tuning the surface properties of materials, either in the form of nano-size or bulk-phase in a particular application.

Cr2S3(Et2DTC) complex and [Cr2S3-MoS2(Et2DTC)] bilayer thin films: single source stationed fabrication, compositional, optical, microstructural and electrochemical investigation

Current investigation has for the first time synthesized chromium sulphide diethyldithiocarbamate [Cr₂S₃(Et₂DTC)] complex utilizing diethyldithiocarbamate (DDTC) utilizing single source precursor method. Thin films of bilayer chromium sulphide diethyldithiocarmate and molybdenum disulphide [Cr₂S₃-MoS₂(Et₂DTC)] were deposited on the fluorine doped tin oxide (FTO) substrate by physical vapour deposition (PVD). Synthesized complex and bilayer were characterized by Xray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectrophotometry (UV-Vis), and scanning electron microscopy (SEM) for exploration of the compositional, optical, crystalline and morphological parameters, respectively. FT-IR peaks expressed the chelation of [Cr₂S₃(Et₂DTC)] expressing interactions between chromium sulphide and the ligand. The band gaps obtained from Tauc plot were 3.89 (direct) and 3.38 eV (indirect), respectively for Cr₂S₃(Et₂DTC) complex. The direct and indirect band gap of 3.75 and 3.35 eV, respectively, were obtained for [Cr₂S₃-MoS₂(Et₂DTC)] bilayer thin films. Average crystallite size of 13 (hexagonal orientation) and 13.4 (orthorhombic orientation) nm and for Cr₂S₃(Et₂DTC) complex and [Cr₂S₃-MoS₂(Et₂DTC)] bilayer thin films expressed from XRD. SEM micrographs expressed cannular and rod protrusions for Cr₂S₃-DDTC complex and smoother and unvarnished surficial characteristics for [Cr₂S₃-MoS₂(Et₂DTC)] bilayer thin films corresponding to compactness and uniformity of the films. Furthermore, [Cr₂S₃-MoS₂(Et₂DTC)] also expressed remarkable electrochemical aspects of the current generation and operational stability of analysed through 5760 s at 100 mA analysed via linear sweep voltammetry and chronoamperometry. The fabricated films can be efficiently used in optoelectronic devices. Current work can be extended to the optimization of bilayer thin films fabrication for achieving an alleviation in the band gaps.

Green Synthesis of MnO Nanoparticles Using Abutilon indicum Leaf Extract for Biological, Photocatalytic, and Adsorption Activities

We report the synthesis of MnO nanoparticles (AI-MnO NAPs) using biological molecules of Abutilon indicum leaf extract. Further, they were evaluated for antibacterial and cytotoxicity activity against different pathogenic microbes (Escherichia coli, Bordetella bronchiseptica, Staphylococcus aureus, and Bacillus subtilis) and HeLa cancerous cells. Synthesized NAPs were also investigated for photocatalytic dye degradation potential against methylene blue (MB), and adsorption activity against Cr(VI) was also determined. Results from Scanning electron microscope (SEM), X-ray powder diffraction (XRD), Energy-dispersive X-ray (EDX), and Fourier-transform infrared spectroscopy (FTIR) confirmed the successful synthesis of NAPs with spherical morphology and crystalline nature. Biological activity results demonstrated that synthesized AI-MnO NAPs exhibited significant antibacterial and cytotoxicity propensities against pathogenic microbes and cancerous cells, respectively, compared with plant extract. Moreover, synthesized AI-MnO NAPs demonstrated the comparable biological activities results to standard drugs. These excellent biological activities results are attributed to the existence of the plant’s biological molecules on their surfaces and small particle size (synergetic effect). Synthesized NAPs displayed better MB-photocatalyzing properties under sunlight than an ultraviolet lamp. The Cr(VI) adsorption result showed that synthesized NAPs efficiently adsorbed more Cr(VI) at higher acidic pH than at basic pH. Hence, the current findings suggest that Abutilon indicum is a valuable source for tailoring the potential of NAPs toward various enhanced biological, photocatalytic, and adsorption activities. Consequently, the plant’s biological molecule-mediated synthesized AI-MnO NAPs could be excellent contenders for future therapeutic applications.

Biosynthesis of zinc oxide nanoparticles with antimicrobial, anticancer, antioxidant and photocatalytic activities by the endophytic Alternaria tenuissima

AIMS

Zinc oxide nanoparticles (ZnONPs) were successfully synthesized using the culture filtrate of the endophytic fungus Alternaria tenuissima as a rapid, eco-friendly and cost-effective method.

METHODS AND RESULTS

The rapid synthesis of ZnONPs was completed after 20 min as confirmed by UV-Vis spectroscopy. The synthesized ZnONPs showed a single-phase crystalline structure. Dynamic light scattering analysis showed that the synthesized ZnONPs were monodispersed and the recorded polydispersity index value was 0·311. Zeta potential value of -23·92 mV indicated the high stability of ZnONPs. Transmission electron microscope revealed the spherical shape and the mean particle size was 15.45 nm. Functional groups present in the prepared samples of ZnONPs were confirmed by Fourier transform infrared spectroscopy. Additionally, the biological activities of in vitro antimicrobial, anticancer, antioxidant as well as the photocatalytic activities were evaluated. ZnONPs showed broad spectrum of antimicrobial potential against all the tested plant and human pathogens. Based on the MTT assay, ZnONPs inhibited the proliferation of normal human melanocytes, human breast and liver cancer cell lines with IC₅₀ concentrations of 55·76, 18·02 and 16·87 µg ml^-1 . ZnONPs exhibited promising antioxidant potential with 50% inhibitory concentration of 102·13 µg ml^-1 . Moreover, ZnONPs showed efficient degradation of methylene blue dye.

CONCLUSIONS

The synthesized ZnONPs showed promising activities that can be better explored in the near future for many medical, agricultural and industrial applications.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study suggests a new and alternate approach with the excellent biotechnological potentiality for the production of ZnONPs which could open up the way for the industrial manufacture of nanoparticles using microbial platforms.