Bharathiar University

About: Bharathiar University is a education organization based out in Coimbatore, Tamil Nadu, India. It is known for research contribution in the topics: Thin film & Adsorption. The organization has 5812 authors who have published 8628 publications receiving 143934 citations. The organization is also known as: BU.

Comparison of antibacterial and antifungal activity of 5-amino-2-mercapto benzimidazole and functionalized Ag3O4 nanoparticles

Abstract: The work focused on the antibacterial and antifungal effect of 5-amino-2-mercapto benzimidazole (AMB), non-functionalized and functionalized Ag3O4 nanoparticles. The synthesized non-functionalized (n-Ag3O4) and functionalized (f-Ag3O4) nanoparticles particle sizes measured 18.72 and 29.11 nm respectively. The XRD results of samples exhibit shift in 2θ values of most prominent peaks due to surface functionalization of Ag3O4 nanoparticles with AMB. The surface functionalization of AMB on Ag3O4 nanoparticles further studied with FT-IR studies, which show the effective binding site is azomethine nitrogen evidenced from the shift of bands at 1635 and 1615 cm−1 in n-Ag3O4 nanoparticles to lower frequency region at 1629 and 1597 cm−1 in f-Ag3O4 nanoparticles. The functionalization of Ag3O4 nanoparticles and surface morphology further confirmed with HR-SEM with EDAX results. The antimicrobial effect of the non-functionalized and functionalized Ag3O4 nanoparticles dispersed in water was investigated. Antimicrobial activities were evaluated against bacterial strain of Pseudomonas aeruginosa, Staphylococcus aureus, and fungi Aspergillus niger used in this work. The n-Ag3O4 nanoparticles exhibit excellent antibacterial and antifungal effect compared to f-Ag3O4 nanoparticles and AMB. The decreased effect of f-Ag3O4 nanoparticles is might be due to increase in particle size and the interaction of silver oxide nanoparticles with bacteria membrane and intracellular proteins decreases with functionalization.

Strategies to design modified activated carbon fibers for the decontamination of water and air

Abstract: The rapid industrialization has induced the entry of organic and inorganic contaminants into the environment at a rate greater than environmental cleaning. As a consequence, pollutants have accumulated in environmental media, thus posing health risk for living organisms. Here, we present surface treatment strategies that modify physicochemical properties of activated carbon fibers for environmental remediation. In particular, we review metals, metal oxides and various advanced materials used for modifying activated carbon fibers. We discuss the utilization of modified activated carbon fibers for adsorption of organic pollutants and inorganic pollutants, and for the degradation of organic pollutants by photocatalysis, electrocatalysis, Fenton process and dielectric barrier discharge. We also discuss air pollutant removal, capacitive deionization, removal of inorganic ions and microbial decontamination by modified activated carbon fibers.

Synthesis of self-assembled micro/nano structured manganese carbonate for high performance, long lifespan asymmetric supercapacitors and investigation of atomic-level intercalation properties of OH− ions via first principle calculation

Abstract: Recent advances in the development of manganese carbonate (MnCO3) have opened up new attractive electrode material for supercapacitor applications. However, limited internal specific capacitance and long cycle stability of MnCO3 due to its low electrical conductivity, poor interfacial properties and simple geometric configurations need to be further improved. Development of smart micro-nano architecture for electrode materials preparation is a critical challenge nevertheless it provides high specific capacitance, rich rate capability and long cycle stability. To achieve this, the facile strategy has been adopted to synthesis self-assembled micro-nano architecture of MnCO3 via simple co-precipitation, microwave and hydrothermal-assisted methods. The proposed first principle calculation study confirmed the weak interaction behaviour between OH− and MnCO3 and tiny volume expansion of unit cell are favourable for rapid charging mechanism and high rate performance. The optimised complex grain growth of 3D MS/NCs MnCO3 electrode delivered an ultrahigh specific capacitance of 302.47 F g−1, high rate capability and long cycle stability. Moreover, an asymmetric supercapacitor is employed in as-prepared 3D MS/NCs MnCO3 as positive electrode and activated carbon as negative electrode which exhibits high specific energy of 18.07 W h kg−1, power density of 7498 W kg−1 and superior capacitance retention of 98.79% even after 10,000 cycles. From these results, we concluded that the self-assembled micro-nano structures are preferred as the future promising electrode architecture for supercapacitors.

Charge compensation assisted enhancement of photoluminescence in combustion derived Li+ co-doped cubic ZrO2:Eu3+ nanophosphors

Abstract: Red light emitting cubic Zr0.99Eu0.01O2:Li+ (0–9 mol%) nanoparticles are synthesized by a low temperature, self-propagating solution combustion method using oxalyl di-hydrazide (ODH) as fuel. In this study, we report systematic investigation of the effect of lithium ion (Li+) concentration on the structural properties and the photoluminescence of zirconia. With increasing lithium concentration, the crystallinity of the samples increases and the lattice strain decreases. The higher crystallinity is likely due to charge compensation achieved by replacing one Zr4+ ion by a Eu3+ and a Li+ ion. Scanning electron micrographs (SEM) reveal a mesoporous structure characteristic of combustion derived nanomaterials. Photoluminescence (PL) spectra show that the intensity of the red emission (606 nm) is highly dependent on Li+ ion concentration. Furthermore there is a promising enhancement in the associated lifetime. Upon Li+ doping, the PL intensity of the samples is found to increase by two fold compared to the undoped sample. Variation of PL intensity with Li+ concentration is attributed to the differences in probability of non-radiative recombination (relaxing). Intensity parameters (Ω2, Ω) and radiative properties such as transition rates (A), branching ratios (β), stimulated emission cross-section (σe), gain bandwidth (σe × Δλeff) and optical gain (σe × τ) are calculated using the Judd–Ofelt theory. The calculated values suggest that in optimally co-doped samples, in addition to improved crystallinity and charge compensation, the lowering of Eu3+ site symmetry and the increase in the covalency of Eu–O bonding due to interstitial Li are responsible for the observed enhancement in PL intensity.