Showing papers by "L. John Kennedy published in 2008"

Vermicomposting of Solid Waste Generated from Leather Industries Using Epigeic Earthworm Eisenia foetida

Abstract: Animal fleshing (ANFL) generated as solid waste from tannery industries was vermicomposted using the epigeic earthworm Eisenia foetida. The mixing ratio of ANFL with cow dung and agricultural residues as feed mixtures was maintained to be 3:1:1 respectively during the vermicomposting experiments for 50 days. Vermicomposting resulted in the reduction of pH 6.74 and C:N ratio 15.5 compared to the control sample. A notable increase in earthworm biomass was also observed in the vermin bioreactor. The germination index of 84% for tomato seedlings (Lycopersicon esculentum cv. PKM1) was observed for the vermicomposted soil. Scanning electron microscope and Fourier transform infrared spectroscopy were recorded to identify the changes in surface morphology and functional groups in the control and vermicomposted samples. The results obtained from the present study indicated that the earthworm E. foetida was able to convert ANFL into nutrient-enriched products.

Preparation and VOC gas sensing properties of Sr(II)-added copper aluminate spinel composites

Abstract: Pure and strontium(II)-added CuAl 2 O 4 composites prepared by sol–gel technology were investigated for their sensing properties towards volatile organic compounds (VOCs) like benzene, toluene, hexane, heptane and acetic acid. X-ray diffraction, scanning electron microscopy (SEM) and nitrogen adsorption/desorption isotherms at 77 K were employed to identify the structural phases, surface morphology and BET surface area of the composites, respectively. The results revealed that the sensitivity factor increased with an increase in temperature up to the optimum temperature at which the maximum sensitivity was obtained and thereafter progressively decreased. Among all the composites tested, CuSA5 (the Cu:Sr molar ratio was kept as 0.2:0.8) showed the highest sensitivity to all VOCs under investigation. The sensitivity factor ( S f ) data in the studied temperature range for all the vapors were employed to fit the Gaussian function. The fit parameters revealed that the data satisfactorily fitted for hexane and acetic acid vapors than the other vapors taken for the study.

Copper Impregnated Mesoporous Activated Carbon as a High Efficient Catalyst for the Complete Destruction of Pathogens in Water

Abstract: Copper impregnated mesoporous activated carbon catalyst was applied for the elimination of microorganisms in wastewater. The antibacterial activity of the catalyst was determined qualitatively by testing the removal of pathogens in water after contacting with the catalyst. Escherichia coli, Shigella flexneri, Shigella dysenteriae, Shigella sonnei, and Salmonella typhi were taken as the model pathogens in determining the antimicrobial activity of the catalyst. The catalyst developed for this purpose was thoroughly characterized using instrumental techniques such as BET analysis, X-ray diffraction, FTIR spectroscopy, and scanning electron microscope to determine the pore and surface area, structural phases, surface functional groups, and surface morphology respectively. The energy dispersive X-ray analysis carried out confirmed qualitatively the percentage of copper impregnated in the catalyst. The experimental studies revealed that the catalyst was highly efficient and advantageous to be employed for industrial applications because of the nonleacheablity of copper from the catalyst and nonreoccurrence of the pathogens in the treated water. The transmission electron microscopy evidenced the complete cell wall rupture of the microorganisms. All the experimental results revealed that the copper impregnated mesoporous activated carbon exhibited a strong and long term antibacterial activity throughout the studies for repeated cycles. © 2007 American Institute of Chemical Engineers Environ Prog, 2008

Alcohol sensing properties of sol–gel prepared Sr(II)-added cobalt aluminate spinel composites

Abstract: Strontium(II)-added CoAl 2 O 4 composites prepared by sol–gel technique were investigated for the sensing properties to alcohols like methanol, ethanol, isopropanol and butanol. X-ray diffraction, scanning electron microscopy and nitrogen adsorption/desorption isotherms at 77 K were employed to identify the structural phases, surface morphology and BET surface area of the composites, respectively. The composites were prepared with the molar ratios of Co:Sr as 1.0:0.0, 0.0:1.0, 0.8:0.2, 0.6:0.4, 0.4:0.6, and 0.2:0.8, keeping the aluminum molar ratio as constant and were labeled as CoSA1, CoSA2, CoSA3, CoSA4, CoSA5 and SA, respectively. The samples sintered at 900 °C for 5 h, were subjected to dc resistance measurements in the temperature range from 30 to 250 °C to study the alcohol vapor sensing characteristics. The results revealed that the sensitivity factor ( S f ) increased with temperature up to the optimum temperature at which maximum sensitivity is obtained and thereafter decreased. The sensitivity factor was found to increase with increase in concentration from 100 to 5000 ppm at the respective operating temperatures. Among the composites prepared CoSA5 showed the maximum sensitivity factor towards alcohols. The sensitivity factor and response and recovery characteristics showed that the order of sensing alcohols by the composites was butanol > isopropanol > ethanol > methanol, which could be explained on the basis of oxidation of alcohols. The stability of the most sensitive composite CoSA5 was also discussed along with the mechanism of sensing. The response and recovery characteristics of CoSA1, CoSA5 and SA to alcohols were also reported.