Development of regenerative dye impregnated mesoporous silica materials for assessing exposure to ammonia

The mesostructured materials MCM-41 and SBA-15 were studied as possible supports of bromocresol green (BG) dye impregnation for the ammonia gas detection because of their large surface area, high regenerative property, and high thermal stability. X-ray diffraction, transmission electron microscopy, scanning electron microscope, and N2 adsorption analysis were used to characterize the prepared materials. These materials could sense ammonia via visible color change from yellowish-orange to blue color. The color change process of the nanostructured materials was fully reversible during 10 cyclic tests. The results indicated that the ammonia absorption responses of the two nanostructured materials were both very sensitive, and high linear correlation and high precision were achieved. As the gaseous ammonia concentrations were 50 and 5 ppmv, the response times for the SBA-15/BG were only 1 and 5 min, respectively. Moreover the BG dye-impregnated SBA-15 was less affected by the variation in the relative humidity. It also had faster response for the detection of NH3, as well as lower manufacturing price as compared to that of the dye-impregnated MCM-41. Such feature enables SBA-15/BG to be a very promising material for the detection of ammonia gas.     

Influence of metal resistant-plant growth-promoting bacteria on the growth of Ricinus communis in soil contaminated with heavy metals

The metal resistant-plant growth-promoting bacterial (PGPB) strains PsM6 and PjM15 isolated from a serpentine soil were characterized as Pseudomonas sp. and Pseudomonas jessenii, respectively, on the basis of their morphological, physiological, biochemical characteristics and 16S rDNA sequences. Assessment of plant growth-promoting parameters revealed the intrinsic ability of the strains for the utilization of 1-aminocyclopropane-1-carboxylic acid as the sole N source, solubilization of insoluble phosphate and production of indole-3-acetic acid (IAA). Further, a pot experiment was conducted to elucidate the effects of inoculating metal resistant PGPB on the plant growth and the uptake of Ni, Cu and Zn by Ricinus communis. Inoculation of Pseudomonas sp. PsM6 or P. jessenii PjM15 increased the shoot and root biomass of R. communis grown in non-contaminated and contaminated soil. However, the maximum biomass was observed in the plants inoculated with strain PjM15. This effect can be attributed to the solubilization of phosphate and production of IAA. Inoculation of Pseudomonas sp. PsM6 and PjM15 did not greatly alter the organ metal concentrations except Zn which concentration was higher in root, stem and leaf of inoculated plants. The results of metal extraction with PGPB strains showed that PsM6 was more efficient at solubilizing Zn than PjM15, and that PjM15 was better at solubilising Ni and Cu than PsM6. Owing to its wide action spectrum, the metal resistant PGPB could serve as an effective metal sequestering and growth-promoting bioinoculant for plants in metal-stressed soil. The present study has provided a new insight into the phytoremediation of metal-contaminated soil.     

Real-world vehicle emissions: A summary of the 15th coordinating research council on-road vehicle emissions workshop

The Coordinating Research Council held its 15th workshop in April 2005, with nearly 90 presentations describing the most recent mobile source-related emissions research. In this paper, the authors summarize the presentations from researchers who are engaged in improving our understanding of the contribution of mobile sources to air quality. Participants in the workshop discussed emission models and emission inventories, results from gas- and particle-phase emissions studies from spark-ignition and diesel-powered vehicles (with an emphasis in this workshop on particle emissions), effects of fuels on emissions, evaluation of in-use emissions control programs, and efforts to improve our capabilities in performing on-board emissions measurements, as well as topics for future research.     

Comparative analysis for the production of fatty acid alkyl esterase using whole cell biocatalyst and purified enzyme from Rhizopus oryzae on waste cooking oil (sunflower oil)

The petroleum fuel is nearing the line of extinction. Recent research and technology have provided promising outcomes to rely on biodiesel as the alternative and conventional source of fuel. The use of renewable source - vegetable oil constitutes the main stream of research. In this preliminary study, Waste Cooking Oil (WCO) was used as the substrate for biodiesel production. Lipase enzyme producing fungi Rhizopus oryzae 262 and commercially available pure lipase enzyme were used for comparative study in the production of Fatty Acid Alkyl Esters (FAAE). The whole cell (RO 262) and pure lipase enzyme (PE) were immobilized using calcium alginate beads. Calcium alginate was prepared by optimizing with different molar ratios of calcium chloride and different per cent sodium alginate. Entrapment immobilization was done for whole cell biocatalyst (WCB). PE was also immobilized by entrapment for the transesterification reaction. Seven different solvents - methanol, ethanol, n-propanol, n-butanol, iso-propanol, iso-butanol and iso-amyl alcohol were used as the acyl acceptors. The reaction parameters like temperature (30°C), molar ratio (1:3 - oil:solvent), reaction time (24 h), and amount of enzyme (10% mass ratio to oil) were also optimized for methanol alone. The same parameters were adopted for the other acyl acceptors too. Among the different acyl acceptors - methanol, whose reaction parameters were optimized showed maximum conversion of triglycerides to FAAE-94% with PE and 84% with WCB. On the whole, PE showed better catalytic converting ability with all the acyl acceptor compared to WCB. Gas chromatography analysis (GC) was done to determine the fatty acid composition of WCO (sunflower oil) and FAAE production with different acyl acceptors.     

Removal of congo red from aqueous solution by bagasse fly ash and activated carbon: kinetic study and equilibrium isotherm analyses

Present investigation deals with the utilisation of bagasse fly ash (BFA) (generated as a waste material from bagasse fired boilers) and the use of activated carbons-commercial grade (ACC) and laboratory grade (ACL), as adsorbents for the removal of congo red (CR) from aqueous solutions. Batch studies were conducted to evaluate the adsorption capacity of BFA, ACC and ACL and the effects of initial pH (pH(0)), contact time and initial dye concentration on adsorption. The pH(0) of the dye solution strongly affected the chemistry of both the dye molecules and BFA in an aqueous solution. The effective pH(0) was 7.0 for adsorption on BFA. Kinetic studies showed that the adsorption of CR on all the adsorbents was a gradual process. Equilibrium reached in about 4h contact time. Optimum BFA, ACC and ACL dosages were found to be 1, 20 and 2 g l(-1), respectively. CR uptake by the adsorbents followed pseudo-second-order kinetics. Equilibrium isotherms for the adsorption of CR on BFA, ACC and ACL were analysed by the Freundlich, Langmuir, Redlich-Peterson, and Temkin isotherm equations. Error analysis showed that the R-P isotherm best-fits the CR adsorption isotherm data on all adsorbents. The Freundlich isotherm also shows comparable fit. Thermodynamics showed that the adsorption of CR on BFA was most favourable in comparison to activated carbons.     

Effect of rubber factory effluent on seed germination and seedling growth of Vigna radiatus L

Physico-chemical analysis of the rubber factory effluents revealed high amounts of total suspended and dissolved solids. Sulphate, phosphate, total nitrogen were also present in significant amounts. At higher concentration (above 50%) of effluent, the seed germination percentage was retarded. Diluted effluent (upto 50%) favoured seedling growth. Length of root system, shoot system and number of lateral roots were increased by low concentrations of effluent.     

Bioaccumulation of organochlorine pollutants in the fish community in Lake Årungen,Norway

Organochlorine pollutants in the major fish species (pike Esox lucius, perch Perca fluviatilis, and roach Rutilus rutilus) of Lake Årungen, Norway, were investigated after an extensive removal of large pike in 2004. The organochlorine pollutants detected in fish liver samples in 2005 were dichlorodiphenyltrichloroethane (DDTs), polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), and heptachlor epoxide (HCE). DDTs were the dominant among all analyzed OCs. ΣPCB and HCB, detected in fish from two clearly distinct trophic levels (prey and predators), give an indication of biomagnification. All OC concentrations in female pike were significantly lower compared to males, which might be due to the removal of high concentrations of pollutants in roe during spawning.     

Engineering of mono-dispersed mesoporous TiO2 over 1-D nanorods for water purification under visible light irradiation

Environmental Science and Pollution Research - Herein we synthesized a novel structure of mesoporous TiO2 decorated on 1D ZnO nanorods for environmental remediation. The effect of mesoporous TiO2...     

The Accuracy of Mortality Reporting in Displaced Persons Camps During the Post-emergency Phase

For humanitarian organisations, accurate data are essential to identify emerging health problems and determine programme needs. We visited 45 post-emergency phase displaced persons camps and collected three months' mortality data which we compared with organisations' routine mortality reports. Organisations reported 612 deaths and we identified 741 deaths, for a mortality-reporting ratio, defined as the number of organisation-reported deaths divided by the number of investigator-identified deaths, of 83 per cent. For the majority of camps which under-reported deaths, mortality reporting ratios were significantly higher for women than men, and for camps with central mortality registers rather than those without. In the few camps which over-reported deaths, these occurred primarily among children younger than five years of age, probably due to the inclusion of abortions and stillbirths. Despite the overall under-reporting of deaths by humanitarian organisations, the existing health information systems appear to estimate mortality rates adequately in these post-emergency camps. However, organisations should improve the precision and completeness with which they report the characteristics of deaths in order to provide valuable data to target their programmes at the most vulnerable people.     

Haematological,biochemical, enzymological and histological responses of Labeo rohita exposed to methyl orange dye solution treated with Oedogonium subplagiostomum AP1

Environmental Science and Pollution Research - The present investigation is an attempt to assess the impact of untreated methyl orange and Oedogonium subplagiostomum AP1 treated methyl orange dye...