NOPR Collection:

Zirconia-chitosan beads as highly efficient adsorbent for defluoridation of water

2020-09-01T06:31:57Z

Title: Zirconia-chitosan beads as highly efficient adsorbent for defluoridation of water Authors: Tandekar, Swati; Saravanan, D.; Jugade, Ravin Abstract: Zirconia modified chitosan beads (Zr-CTS) have been synthesized as adsorbent for fluoride ions from water bodies. The beads have been characterized using FTIR, SEM, EDX, TG-DTA and BET surface area analysis. Batch adsorption parameters are performed for defluoridation of water using the prepared composite. The pH point of zero charge was found to be 5.7. Maximum efficiency of the adsorbent is observed at pH 4.0, with adsorbent dose of 40 mg per 25 mL of 25 ppm fluoride solution and adsorption period of 45 min. Under these conditions, Zr-CTS is found to have an adsorption capacity of 52.63 mg g^-1 in accordance with Freundlich adsorption isotherm. Thermodynamics parameters reveal that the process of adsorption was spontaneous, exothermic and leading to increase in entropy. The process follows pseudo-second-order kinetics model. The used material is regenerated using 5% NaCl solution and could be reused in multiple cycles adding greener dimension. Page(s): 1067-1075

Reactivity of electrochemically synthesised zinc nanofiber in facile reduction of nitro and azide compounds

2020-09-03T17:22:15Z

Title: Reactivity of electrochemically synthesised zinc nanofiber in facile reduction of nitro and azide compounds Authors: Mandal, Siba Prasad; Mondal, Bibhas; Saha, Rajat; Kundu, Mousumi; Roy, Ujjal Kanti Abstract: Electrochemistry is used in generation of metallic nano zinc wire from aqueous zinc chloride. For this electrochemical process we have designed a unit galvanic cell. During the electrochemical process both aliphatic and aromatic nitro and azide compounds undergo facile reduction to the corresponding amines. ZnCl₂ is used as stoichiometric reagent and causes electrochemical deposition of zinc in cathode. During the process wire shaped nano zinc architecture has been formed in cathode which is supposed to be the active reagent for reduction. The cathode deposited material has been characterised by powder XRD, XPS, FESEM, HRTEM, EDX, SQUID etc. The corresponding amines are prepared in good yields. Both zinc salts and aqueous solution can be recycled. Page(s): 1076-1083

Cadmium sulfide decorated with carbon nanoparticles from peanut shells: An efficient photocatalyst

2020-09-01T06:26:54Z

Title: Cadmium sulfide decorated with carbon nanoparticles from peanut shells: An efficient photocatalyst Authors: Sawant, V. J.; Lavate, D.A.; Khomane, A.S. Abstract: Carbon decorated cadmium sulfide nanoparticles have been synthesized by chemical precipitation method in aqueous medium using dichloroacetic acid as a complexing agent to study their optical and photocatalytic properties. Carbon nanoparticles have been prepared from waste peanut shells by simple pyrolysis method. The as-prepared materials have been characterized by XRD analysis, UV-visible diffuse reflectance spectroscopy, spectrofluorometer, FTIR and BET analysis. SEM and TEM images indicate nano crystallites with spherical agglomeration of average 40 nm size. Band gap energy for pure CdS is observed in the order of 2.4 eV. As prepared carbon decorated CdS nanoparticles with increased surface area efficiently catalyzed the photodegradation of Rhodamine B dye solution under sunlight irradiation than pure CdS. Page(s): 1084-1091

Synthesis, characterization and photocatalytic dye degradation studies of novel defect pyrochlore, KHf0.5Te1.5O6

2020-09-01T06:24:32Z

Title: Synthesis, characterization and photocatalytic dye degradation studies of novel defect pyrochlore, KHf0.5Te1.5O6 Authors: Sudheera, M.; Ravinder, G.; Ravi, G.; Venkataswamy, P.; Vaishnavi, K.; Chittibabu, N.; Vithal, M. Abstract: In this study, KHf_0.5Te_1.5O₆ (KHTO) semiconductor has been synthesized by the solid-state method. The synthesized material is characterized using X-ray diffraction, Fourier transform infrared spectroscopy, UV-visible diffuse reflectance spectroscopy, field emission-scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy and N₂ adsorption/desorption measurements. The material is found to be crystallized in a cubic lattice with the space group Fdm . The bandgap energy of the KHTO is 2.6 eV. The photocatalytic activity of KHTO has been investigated by measuring the degradation of methylene blue (MB) and methyl violet (MV) dyes under the visible light irradiation. The mechanistic dye degradation pathway of MB has been studied. The radical quenching experiments reveal that the short-lived species O₂^●-, OH^●, and h⁺ actively participate in the degradation of MB and MV dyes. An additional terephthalic acid experiment has been carried out to establish the participation of OH^● radicals in the dye degradation. The stability and reusability of the KHTO catalyst are also studied. Page(s): 1092-1099