National Institute of Technology, Karnataka

About: National Institute of Technology, Karnataka is a education organization based out in Mangalore, Karnataka, India. It is known for research contribution in the topics: Corrosion & Cloud computing. The organization has 5017 authors who have published 7057 publications receiving 70367 citations.

Dye degradation studies using immobilized pristine and waste polystyrene-TiO2/rGO/g-C3N4 nanocomposite photocatalytic film in a novel airlift reactor under solar light

Abstract: Complex dyes are not completely removed in most wastewater treatment plants and thus released into nearby waterbodies posing problems to aquatic life and humans. In this study, a chemically synthesized nanocomposite photocatalyst containing TiO2, rGO and g-C3N4 immobilized in a polystyrene film is evaluated for the degradation of the Cu-phthalocyanine complex dye (Remazol Turquoise Blue, RTB) in a multiphase airlift reactor under sunlight. Both pristine and waste polystyrene were used in the synthesis of the film. The characterisation of the powder photocatalyst composite as well as the immobilized photocatalyst film is performed using particle size analyzer, SEM-EDX, BET, XRD, XPS, FTIR, and ICP-OES. The optimization of various parameters affecting the photocatalytic decolourization such as the g-C3N4 quantity in the composite catalyst, catalyst loading, the initial concentration of dye, use of waste polystyrene and catalyst reuse has been studied thoroughly. The photocatalytic treatment of RTB dye under optimum conditions for 90 min shows that the decolourization (60%) and degradation (51.43%) as measured by TOC analysis are quite similar. The possible breakdown compounds from the parent molecule after the photocatalytic operation are identified by HPLC-MS. In conclusion, the immobilized nano-composite photocatalyst incorporated into a multiphase airlift reactor, is a very promising system to improve the water quality by TOC reduction, before discharge to nearby natural water sources.

Synthesis of BaWO 4 /NRGO‒g-C 3 N 4 nanocomposites with excellent multifunctional catalytic performance via microwave approach

Abstract: Novel barium tungstate/nitrogen-doped reduced graphene oxide-graphitic carbon nitride (BaWO4/NRGO-g-C3N4) nanocomposite has been synthesized by a simple one-pot microwave technique. The synthesized nanocomposites are well characterized by diffraction, microscopic and spectroscopic techniques to study its crystal structure, elemental composition, morphological features and optical properties. The material prepared is tested for its performance as an electrocatalyst, photocatalyst and reduction catalyst. The nanocomposite catalyzed the photodegradation of methylene blue (MB) dye in 120 min, reduction of 4-nitro phenol (4-NP) to 4-amino phenol (4-AP) in 60 s, showed an impressive Tafel slope of 62 mV/dec for hydrogen evolution reaction (HER). The observed results suggest that the nanocomposite acts as an efficient multifunctional catalyst. The reported approach provides fundamental insights which can be extended to other metal tungstate-based ternary composites for applications in the field of clean energy and environment in the future.

Molecular design and theoretical investigation of new metal-free heteroaromatic dyes with D-π-A architecture as photosensitizers for DSSC application

Abstract: Herein, we report design, synthesis and photovoltaic performance of four new metal-free heteroaromatic dyes ( P 1-4 ) with D-π-A architecture carrying electron donating carbazole core connected to four different electron withdrawing/anchoring groups, viz cyanoacetic acid, rhodanine-3-acetic acid, barbituric acid and thiobarbituric acid and phenylene ring as a π-spacer The newly designed P 1-4 were synthesized from carbazole derivative using Suzuki cross coupling approach followed by Knoevenagel condensation reaction Their structures were confirmed by FTIR, NMR, Mass spectral and elemental analyses The dyes were subjected to optical and electrochemical studies in order to investigate their absorption/emission behavior as well as HOMO/LUMO energies The UV–vis spectral studies reveal that the P 1-4 showed λ max at 412, 439, 458 and 489 nm, respectively Their optical band-gap is in the range of 217 to 261 eV and fluorescence quantum yield is in the order of 44–70% From energy level diagram, it is clear that all the dyes possess good thermodynamic feasibility for electron injection into CB edge of TiO 2 as well as their regeneration from electrolyte system The photovoltaic performance studies indicate that among the tested dyes, P 1 anchored with cyanoacetic acid displayed the highest IPCE (32%), resulting in improved PCE (194%), J SC (468 mA cm −2 ), V OC (0588 V) and FF (703%) values, when compared to other dyes Finally, DFT studies were performed using Turbomole 71 V software to investigate their electron cloud delocalization in HOMO/LUMO levels and theoretical absorption spectral data The results reveal that the dye P 1 showed effective charge separation in its FMO levels, which has reflected in its ICT behavior and hence P 1 displayed the improved photovoltaic performance

Mechanical behavior of woven natural fiber fabric composites: Effect of weaving architecture, intra-ply hybridization and stacking sequence of fabrics

Abstract: A comprehensive analysis carried out on the mechanical and free vibration properties of woven natural fiber polymer composites is presented. Jute fabric with three different weave types (plain, bas...

Photocatalytic degradation of phenol using Ag core-TiO2 shell (Ag@TiO2) nanoparticles under UV light irradiation.

Abstract: Ag@TiO2 nanoparticles were synthesized by one pot synthesis method with postcalcination. These nanoparticles were tested for their photocatalytic efficacies in degradation of phenol both in free and immobilized forms under UV light irradiation through batch experiments. Ag@TiO2 nanoparticles were found to be the effective photocatalysts for degradation of phenol. The effects of factors such as pH, initial phenol concentration, and catalyst loading on phenol degradation were evaluated, and these factors were found to influence the process efficiency. The optimum values of these factors were determined to maximize the phenol degradation. The efficacy of the nanoparticles immobilized on cellulose acetate film was inferior to that of free nanoparticles in UV photocatalysis due to light penetration problem and diffusional limitations. The performance of fluidized bed photocatalytic reactor operated under batch with recycle mode was evaluated for UV photocatalysis with immobilized Ag@TiO2 nanoparticles. In the fluidized bed reactor, the percentage degradation of phenol was found to increase with the increase in catalyst loading.