Showing papers by "L. John Kennedy published in 2011"

Photocatalytic degradation of phenolic syntan using TiO2 impregnated activated carbon

Abstract: Investigations were carried out to study the photocatalytic degradation of phenolic syntan (PS), a widely used environmentally polluting chemical in the leather tanning industry. Photocatalytic inactive commercial TiO(2) was used as the precursor for the preparation of TiO(2) impregnated activated carbon (Ti-AC) photocatalyst. Experiments were conducted by varying the concentrations of PS solution (50-1000 mg/l), pH (2.5-10) and time intervals to optimize the working parameters. A 254 nm UV light was used throughout the study. The effect of PS degradation using Ti-AC was also compared with direct UV photolysis. The Ti-AC was characterized using X-ray Diffraction (XRD), Diffuse Reflectance Spectroscopy (DRS), Scanning Electron Microscopy (SEM) and energy dispersive X-ray analysis (EDX) to determine the structural, optical, surface morphology and elemental analysis respectively. X-ray studies revealed the formation of catalytically active anatase phase in Ti-AC. Photodegradation of PS was examined by chemical oxygen demand (COD) method. PS degradation occurred at both the extreme end of acidic and alkaline pH conditions. However, the percentage degradation was comparatively higher at pH 2.5. The photodegradation followed pseudo first order kinetics. UV-Visible studies substantiated the occurrence of bathochromic and hyperchromic effects as a result of ring opening in the PS molecule.

Synthesis and characterization of plant ceramics doped tin oxide for humidity sensing application

Abstract: The mineral oxides derived from the plant seeds Hygrophila Spinosa T. anders (HST) termed to be plant ceramics (PC) has been chosen as a dopant in the SnO 2 matrix inview of evaluating as a new sensor material. Different compositions of the precursors were prepared to optimize for achieving high humidity sensitivity. The synthesized materials were characterized for structural behaviour, vibrational functional groups, BET surface area, surface morphology and elemental analysis from X-ray diffraction, FT-IR spectra, N 2 adsorption/desorption isotherm at 77K, Scanning electron micrograph and Energy dispersive X-ray analysis respectively. The PC doped SnO 2 was evidenced from the X-ray diffraction spectra. Two probe DC-electrical resistance method at different humidity levels were used to determine the sensitivity values. Of the various compositions prepared, SnO 2 -PC 2 showed comparatively higher humidity sensitivity (S f ) value, 4013 ± 265. A fast response and recovery time of 80s and 140s respectively was also achieved indicating the suitability of the PC doped SnO 2 as a good humidity sensor.

Catalytic Applications of Nano β‐PbO in Paal—Knorr Reaction.

Abstract: Nano lead oxide is found to be an efficient recyclable catalyst for the condensation of 2,5-hexandione with primary amines to yield pyrroles.