Volume 239, Issue 5 - Special Issue: Solar Water Splitting And Artificial Photosynthesis (SWAP), Part 6; Guest Editors: Kevin Bethke, Jeyanthinath Mayandi and Smagul Karazhanov

This study examined the methods for preparing biocarbon from Teff hay (TBC) and thiol-grafted seed gum of Tamarindus indica (TH@TI-TBC) with the purpose of removing cadmium (Cd) from polluted electroplating waste water. To improve biocarbon adsorption, seed gum and thiol were added in a two-step combination. At a pH of 5.5, the most effective Cd adsorption was seen with TH@TI-TBC (261.47 mg g −1 ). While comparing to the Freundlich and Temkin models, the Langmuir and pseudo-second-order kinetic models found to be the best fit to the obtained adsorption data. After being treated with electroplating wastewater having 30 mg −1  L of cadmium, TH@TI-TBC was able to remove up to 89 % of the Cd, proving its effectiveness in dealing with adsorptive removal of Cd. Experimental studies and computational analyses revealed that electrostatic interaction and surface complexation were the principal underlying processes for Cd removal by TH@TI-TBC. In addition, an innovative material that can transform the waste into a product for environmental remediation must be developed using the vast amounts of Teff hay that are generated as agro-residue. So, this work proved that TH@TI-TBC can be made from Teff hay biocarbon could be a potential candidate for removing Cd from industrial wastewater.

The objective of this investigation is to explore how doping chitosan (Chi) with different lanthanide oxides (LnO) such as cerium, neodymium, samarium, europium, gadolinium, dysprosium, and holmium oxides affects its thermodynamic properties. Especially the effect of lanthanide contraction which is the competition between mass and size has been investigated and reported. The investigation describes a method for calculating various physical properties of a Chi-LnO composite material based on experimental values of refractive index, density, viscosity, and ultrasonic velocity concerning the mass and size of the LnO doped with chitosan. These properties play crucial roles in understanding the behavior and characteristics of composite materials. The process involves deriving the physical properties such as dielectric constant, intermolecular free path length, relaxation time, ultrasonic attenuation, relative association, surface tension, Gibbs free energy and non-linearity parameters are calculated from the experimental value of the refractive index, density, viscosity and ultrasonic velocity properties from the given experimental data and results are discussed in a detailed manner.

The shock wave impact on hydrogen-bonded organic materials’ structural properties and their responses with respect to their associated functional properties is one of the most prevalent research topics because of the possible emergence of unusual functional properties. Presently, we intend to examine the structural response of the poly-crystalline picric acid samples under shocked conditions. The crystallographic structural responses and the linear optical properties of the test samples have been examined by powder XRD analysis, ultra-violet diffused reflectance spectroscopy (UV-DRS) and Raman spectroscopy, respectively. Under shocked conditions, a considerable modification in the diffraction peak positions and their intensity changes could be witnessed. Notably, linear optical transmittance profiles show remarkable changes according to the number of applied shock pulses, such that the 150-shocked sample has the highest optical transmittance of 53.9 % at 350 nm, whereas the control sample has an optical transmittance of 6.6 %. The Raman spectrum shows the vibrational groups of material that are stable in shocked conditions with similar intensity changes. Based on the obtained XRD, UV-DRS and Raman results, shock wave-induced picric acid samples have remarkably improved characteristics of optical transmittance, which is highly favorable for non-linear optical applications.

The green hydrogen generation by photoelectrochemical (PEC) process emerged as a viable approach to replace non-renewable energy sources, which is done by using semiconducting materials. Recently ZnSe-based heterostructure/junction promise a suitable approach to enhance the PEC performance of photoelectrode. Here we have grown Bi 2 Se 3 /ZnSe heterojunction on flexible Mo metal foil by using magnetron sputtering technique toward PEC water splitting application. The crystallinity, structural, and surface morphology of the deposited films were investigated by X-ray diffraction, Raman spectroscopy, and field emission scanning electron microscopy, respectively. The PEC measurements were performed under 100 mW/cm 2 (AM = 1.5 G) simulated solar radiation in 0.5 M Na 2 SO 4 aqueous electrolyte solution. The PEC measurements show that Bi 2 Se 3 /ZnSe photoelectrode performs better as a photocatalyst, with a photocurrent density of ∼96.4 μA/cm 2 (at 0.4 V vs Ag/AgCl), which was found to be three times higher than pristine ZnSe film (∼32.4 μA/cm 2 ). This work suggests the importance of heterojunction towards efficient photoelectrodes for green hydrogen generation.

The bioinorganic material, such as fish mucus macromolecules crowned zirconia nanoparticles (ZrO 2 NPs) was synthesized via green methodology and has been investigated their efficacy on Gram-positive and Gram-negative bacterial strains that inhabit the oral cavity, gastrointestinal tracts, and colon. The environmentally benign synthesis methodology was used for fabricating biofunctionalized ZrO 2 NPs with three different concentrations of C. striatus epidermal mucus. Spherical morphology with a size ranging from 7 to 25 nm of synthesized granular was identified by FESEM analysis. The powder XRD diffractions of synthesized ZrO 2 NPs were confirmed with the previously reported standard literature. Upon being subjected to a primary microbial study, the synthesized ZrO 2 NPs were shown to exhibit antibacterial activity against the tested bacterial pathogens. However, another Gram-negative bacterial stain, Proteus vulgaris shows almost similar efficiency to standard antibacterial drugs. Interestingly, all Gram-positive bacterial strains show a high zone of inhibition at higher concentrations of synthesized ZrO 2  NPs. In general, the antibacterial activity study proved that the synthesized biofunctionalized ZrO 2 NPs may be applied as an efficient health care beneficial material.

Remediating water contamination greatly benefits from the removal of chemical as well as microbiological contaminants using the same substance. Yttrium-doped Lanthanum Titanate (LaY x Ti 1− x O 3 , where x  = 0 (LTO) and 0.05 (LYTO)) nanoparticles (NPs) synthesized by the auto-combustion method were already proven to have better antibacterial activities. The current study aims to investigate the photocatalytic degradation efficiency of the same sample for the organic pollutant Methylene Blue (MB) dye. Here, two vital and decisive characterization methods were employed: Raman spectroscopy for chemical and morphological features and X-ray photoelectron spectroscopy (XPS) for surface phase identification. The oxidation states of La 3+ and Ti 3+ ions have been deduced using XPS. The HRTEM reveals the nano-structure with SAED pattern is supporting with XRD data. LaTiO 3 (LTO) and LaY 0.05 Ti 0.95 O 3 (LYTO) nanoparticles showed degradation efficiencies of 40.26 % and 86.24 %, respectively, at degrading methylene blue (MB) dye after a reaction time of 90 min. The degradation efficiency of LTO increased to 87.19 % after a reaction time of 150 min. The introduction of yttrium doping into lithium titanate demonstrates promise as a material for mitigating water treatment, as it augments the material’s antibacterial and photocatalytic characteristics.

In recent years, hybrid natural fiber–reinforced composites prepared by bio-based epoxy resin (BBER) have gained extensive usage due to their exceptional specific strength. Researchers have looked at natural fibre/BBER composites because of the vast array of technical uses for these materials. Experimenting with various composition combinations of hybrid natural fiber composites to improve their mechanical properties requires a significant amount of resources. The purpose of this research was to develop and evaluate a tannic acid (TA) – based bio-based epoxy resin (BBER). The synthesized BBER was analyzed using FTIR spectroscopy. The bio-resin’s thermal characteristics were assessed using TGA, DSC, and OIT studies. Further, this study investigated the mechanical characteristics of hybrid composites prepared by Holoptelea integrifolia (HIBF) bark fibre reinforced with Ziziphus jujuba Seed Particles (ZJSP) which was manufactured using BBER. In the present study, a full factorial design was used to conduct experiments, which included three variables: the percentage of HIBF fibre by weight, the particle size of ZJSP, and the percentage of ZJSP by weight. The experimental results from the mechanical evaluation of the hybrid HIBF/ZJSP using BBER composites are then used to develop a fuzzy model that predicts mechanical parameters such as tensile strength (TS), flexural strength (FS), and impact strength (IS). An accurate prediction of the mechanical characteristics of hybridized composites made by the fuzzy model owing to the membership functions that were built. To further validate the fuzzy model, a set of tests utilising test cases were conducted. The model’s accuracy in predicting the mechanical characteristics of hybrid composites was determined to be 87 % based on the outcomes of the test cases.

We demonstrate the enhancement in the optical nonlinearity of materials when incorporated within a Tamm plasmon cavity (TPC). This study quantitatively investigates the enhanced nonlinear optical effects exhibited by silver@graphite (Ag@C) core–shell nanostructures integrated within a Tamm plasmon cavity. The Ag@C core–shell nanostructures were synthesized by laser ablation. The transmittance characteristics of the TPC are well-matched with those of the simulated spectra. Nonlinear optical studies, conducted using the open aperture Z-scan technique, demonstrated reverse saturable absorption (RSA) behavior in the Tamm plasmon cavity structure, and a profound enhancement in nonlinear absorption compared to that of the bare material film was also observed. The optical limiting threshold value was found to be 2.5 J/cm 2 which is indeed a better value when compared to the reported values. Computational simulations illustrated a significantly intensified electric field within the Tamm plasmon cavity, suggesting the creation of enhanced photonic states leading to increased light–matter interactions. These findings underscore the potential of Ag@C core–shell nanostructures within Tamm plasmon cavities for advancing nonlinear optical devices and applications.

Imidazolium l- tartrate crystal has been grown by employing the slow evaporation technique using de-ionized water as the solvent. An impact study on the exposure of shock pulses on the surface of the material has been carried out and the influence of shock waves on its photo luminance has been investigated. In the present work, in order to carry out the experiment, a shock wave of Mach number 1.5 has been utilized which has been generated by a semi-automated Reddy Tube. Imidazolium tartrate crystal is made into a fine powder and split into four identical parts to be used for further characterization. A series of shock waves such as 25, 50, and 75 are impacted on the respective samples while keeping one of the samples as the control. The powder X-ray diffraction analysis reveals that the observed increase in peak intensity and peak shifting is due to the increase in the number of shock pulses from 25 to 75. FTIR is performed to analyze the presence of functional groups in the material before and after shock exposure. Photoluminescence measurements are also carried out for the pre- and post-shocked samples to determine the nature of optical emission with respect to various shock pulse counts. The above experimental analyzes confirm that the title sample undergoes a reversible photoluminescence shift induced by shock waves.

In this study, lithium cobalt co-doped titanium oxide (Li:Co-TiO 2 ) was reported via the sol–gel method in a one-pot synthesis approach and their potential applications were evaluated for the photodegradation of organic dye as photocatalysts. The structural and optical properties of the photocatalysts were respectively elucidated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and diffuse reflectance spectroscopy (DRS). The morphological and elemental composition of the Li:Co-TiO 2 was established by high-resolution field-emission scanning electron microscopy (FESEM) coupled with EDX, which confirmed a successful preparation of the photocatalysts. The modification of TiO 2 with Li:Co changes the optical properties of the pristine TiO 2 with a reduction in the bandgap (3.26–2.8 eV) of the resultant photocatalysts. The photocatalytic activity of Li:Co-TiO 2 composites was examined for their efficacy through the degradation of Methylene Blue (MB) dye. The photodegradation revealed an improved performance of Li:Co-TiO 2 in the degradation of MB compared to pristine TiO 2 . The total amount of the degraded MB dye within the total time interval of the irradiation was recorded to be 72 % and 87 % for TiO 2 and Li:Co co-doped TiO 2 respectively. The enhanced results obtained from the photocatalytic activity of Li:Co-TiO 2 to degrade MB, suggest that the composite is a potential candidate for environmental remediation and photocatalysis applications.