NOPR Collection: Special issue on “International Conference on Advances in Chemistry with Specific Reference to Catalysis, Sensors, Drug Delivery and Energy Materials (ICACSEM-2020)” (Guest Editor: Dr E Murugan)

Degradation of Orange G and Malachite green dyes under visible light irradiation: Double layered core-shell nanoparticle as an efficient photocatalyst

2020-09-01T00:00:00Z

Title: Degradation of Orange G and Malachite green dyes under visible light irradiation: Double layered core-shell nanoparticle as an efficient photocatalyst Authors: Josephine, Suganya GA; Sivasamy, A Abstract: Core-shell nanomaterials have emerged as a frontier area of focus in materials chemistry and catalysis. Here, we have explored the photocatalyst potential of a double layered core-shell material comprising a rare earth material as core and silica, zinc oxide as the subsequent shell materials. The prepared core-shell has average particle size of 40-60 nm, and the material has been characterized by FTIR, XRD, UV-DRS and FESEM techniques. The band gap energy of prepared material is 2.82 eV. The photocatalytic activity has been tested against Orange-G and Malachite green dye under visible light irradiation. A comparison for degradation of azo and non-azo dye has been elucidated. Preliminary studies with varying pH, catalyst dosage and initial dye concentration have been done to determine the optimum parameters for photocatalytic activity. The kinetic studies follow pseudo-ﬁrst-order pathway. The prepared core-shell nanomaterial is found efficient for degradation of non-azo dye compared to azo dye. Both the materials show better activity than pristine ZnO. The photocatalyst is found to be environmentally benign with reusability even up to the third cycle of reuse. Page(s): 1259-1264

Novel homogeneous catalyst assisted sonocatalytic degradation of dye Direct Blue 71

2020-09-01T00:00:00Z

Title: Novel homogeneous catalyst assisted sonocatalytic degradation of dye Direct Blue 71 Authors: Bhavani, R; Sivasamy, A Abstract: Industrial effluents, particularly from dye industry, is one of the major causes of serious concern as it contaminates the environmental water resources and affect human health. Treatment of such contaminants is a challenging area of interest to researchers. In this context, here, we have explored degradation and mineralization of Direct Blue (DB71) dye in aqueous solution by means of ultrasound irradiation at a frequency of 25 kHz and its combination with a novel homogenous sonocatalyst is investigated. The following experiments have been conducted to achieve complete degradation of the dye molecule. In-situ generation of the radicals under ultrasonic irradiation is measured by EPR technique. The effects of various operational parameters such as the effects of pH, dye concentration, catalyst dosage, electrolytes, energy input and kinetics of oxidation processes on the degradation efficiency are studied. COD measurements are also carried out in order to evaluate the mineralization efficiency of DB71. The effect of electrolytes on dye degradation is studied with different inorganic electrolytes. The rate constant decreases with increasing dye concentration. The degradation increases with increasing catalyst concentration and decreases with increasing dye concentration. Sonocatalytic degradation of the dye molecules are observed by UV-visible absorption and TOC measurements. The by-products formation of the sonocalytically degraded dye samples are analyzed by ESI-MS+ analysis. The catalyst is also tested for its efficiency in the degradation of real dye house effluents. Page(s): 1265-1272

Solanum melongena leaf extract based zinc oxide nanoparticles synthesis using green chemistry concepts

2020-09-01T00:00:00Z

Title: Solanum melongena leaf extract based zinc oxide nanoparticles synthesis using green chemistry concepts Authors: Nagarajan, A; Sethuraman, V; Balasubramani, V; Sridhar, TM; Sasikumar, R; Vimala, G Abstract: Nanoparticles of zinc oxide (ZnO NPs) have been synthesised from naturally available Eggplant, Solanum melongena leaf extract. The methodology has been optimized to obtain ZnO NPs which as are characterized using UV-Visible, X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and FT-Infra red (FTIR) tools to confirm their nano dimensions and chemical properties. The SPR band is obtained at 389 nm in UV-visible absorption spectrum confirmes the formation of ZnO NPs while the presence of -OH, -C-O, -CH₂ and –COO groups at vibrational frequencies of 3500, 105, 3000 and 1640 cm^-1, respectively are observed from FTIR. Further, the SEM images show regular flakes like structure, and the average distribution of the nanoparticle is found to be around 100 nm. The newly synthesised ZnO NPs using leaf extract of Solanum melongena show considerable activity against both Gram-negative and Gram-positive bacteria. The ZnO NPs is proved to be more potent against Staphylococcus aureus than E. coli. Page(s): 1273-1277

Mechanism of photoinduced charge transfer at MEH-PPV and titanium dioxide nanoparticle interface

2020-09-01T00:00:00Z

Title: Mechanism of photoinduced charge transfer at MEH-PPV and titanium dioxide nanoparticle interface Authors: Shankar, Jaya Seeli; Kumar, Sangeetha Ashok; Periyasami, Bhuvana K; Nayak, Sanjay K Abstract: In this study, we investigated mechanisms of photoinduced electron transfer from a conjugated polymer (poly(2-methoxy-5-(2-ethylhexyloxy) 1,4-phenylenevinylene (MEH-PPV) to titanium dioxide (TiO₂) nanoparticles (acceptor) through steady-state photoluminescence (PL) spectroscopy. Since mixed phase TiO₂has better photocatalytic compared to single phase, it is an efficient charge separation process during photoexcitation of polymer nanocomposites by incorporating the mixed phase TiO₂ nanoparticles into the MEH-PPV polymer matrix through in situ polymerization. Structural characterization revealed only physical interaction between the polymer matrix and dispersed nanoparticles. The absorbance spectra of nanocomposites also indicated the absence of ground state complex formation. Luminescence quenching of polymer nanocomposites compared to pristine MEH-PVV signifies the charge transfer taking place at the MEH-PPV/TiO₂ interfaces. Thus, the MEH-PPV/ mixed phase TiO₂ nanocomposite serves as an active layer for photovoltaic application. Page(s): 1278-1284