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decolorisation,biodegration and detoxificatio of benzidine based azo dye
Get PDFThe present study deals with the decolorisation,biodegration and detoxification of Direct Black-38,a benzidine based azodyes, by a mixed microbial culture isolated from an aerobic bioreactor treating textile wastewater. The studies revealed a biotransforma-tion of Direct Black-38 into benzidine and 4-aminobiphenyl followed by complete decolorisation and biodegradation of these toxic intermediates. From cytotoxicity studies, it was concluded that detoxification of the dye took place after degradation of the toxic intermediates by the culture
Air pollution concentrations of PM2.5,PM10 and No2 at ambient and Kerbsite and their correlation in metro city- Mumbai
No full textAmbient concentrations of PM2.5and PM10 are of concern with respect to effects on human health and environment. Increased levels of mortality and morbidity have been associated with respirable particulate air pollution. In India, it is not yet mandatory to monitor PM2.5 levels therefore very limited information is available on PM2.5 levels. To understand the fine particle pollution and also correlate with PM10 which are monitored regularly in complience with ambient air quality standards. This study was carried out to monitor PM2.5, PM10 and NO2 for about one year in a residential cum commercial area of Mumbai city with a view to understand their correlation. The avarage PM2.5 concentration at ambient and Kebersite was 43 and 69mg/m3. The correlation coefficeient between PM2.5 and PM10 at ambient and Kebsite were 0.83 and 0.85 respectively thus indicating that most of the PM2.5 and PM10 are from similar sources. TSP, PM10 levels exceeded CPCB standards during winter season. PM2.5 levels also exceeded 24 hourly avarage USEPA standards during winter season indicating unhealthy air quality
Characterization and Source Identification of Major Inorganic Ions in Precipitation of Nagpur, India
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Visible light assisted photodegradation of halocarbons on the dye modified TiO2 surface using visible light
No full textVisible light assisted photodegradation of various halocarbons, viz. chloro-phenols,trichloroethylene, 1,2-dichloroethane and 1,4-dichlorobenzene, has been achieved on the surface of dye-modified TiO2 semiconductor. Thionine, eosinY, rhodamineB, methyleneblue,nileblueA and safranineO were used for the modification of TiO2 semiconductor photocatalyst. After 5 h of irradiation with a 150W Xenon lamp, over 55–72% degradation of pollutants has been achieved. A working mechanism involving excitation of surface adsorbed dye, followed by charge injection into the TiO2 conduction band and formation of reactive �O�2 =�HO2 radicals, is proposed for the degradation of the enlisted organics to carbon dioxide. Efficacy of the photocatalytic system towards halocarbon degradation has been discussed in regard to excited state redox properties of the dyes selected for this study.Formation of �O�2 radical has been substantiated by using a chemiluminescent probe luminol
Volatile organic compounds in ambient air of Mumbai—India
No full textVolatile organic compounds (VOCs) are a major group of air pollutants which play a critical role in atmospheric
chemistry. These contribute to toxic oxidants which are harmful to ecosystem, human health and atmosphere. The
variability of pollutants is an important factor in determining human exposure to these chemicals. Data on levels of VOCs in developing countries, including India, are lacking. The present work deals with the estimation of target VOCs at 15 locations of five categories in Mumbai. The categories are residential, industrial, commercial, traffic intersections and petrol refueling stations. The monitoring was carried out during peak hours in the morning and evening, once every month, during May 2001 to April 2002. The study focused on target VOCs as defined by USEPA. Concentrations of benzene, at all the locations, were found to be much above the guidelines values prescribed by World Health Organization (WHO) for ambient air quality. All other VOCs were observed to be below the WHO guideline values. The results show that levels of VOCs in Mumbai were high. There is need for a regular monitoring schedule of VOCs in the urban environment. Variability studies are important to assess the exposure potential of pollutants which are an important parameter for health impact studies. This study also presents the variability of VOCs in the urban area of Mumbai. Variability was divided into measurement spatial, temporal and temporal–spatial interaction components. The temporal component along
with temporal–spatial interaction component were the major contributors to variability. VOCs associated with mobile
source emissions and emissions from marine source were found to be distributed uniformly in the urban atmosphere in
Mumbai. the need for continuous monitoring, to capture short term peak concentrations and averages, is evident
Influence of cooling water discharges from Kaiga nuclear power plant on selected indices applied to plankton population of Kadra reservoir
No full textCondenser cooling water for the Kaiga nuclear power plant, Kaiga of Karnataka state is drawn at the rate of 1,25,205
f7i3hr1 from the Kadra reservoir and discharged back to the reservoir through a 1.2 km long open channel. The heated effluents reduce solubility of oxygen and accelerate loss of oxygen locally due to increased biological activity. Applications of biological indices are the effective tool for the assessment of qualities of water and biota. During the study period of two years 49 and 22 genera of hytoplankton and zooplankton respectively were recorded at surface waters. Diversity indices indicate oligotrophic nature of the lake. Dissimilarity was more amongstthe plankters in between intake and discharge points. Preference of habitats indicates marginal
change of rankings of plankton in zones within 500m and beyond 500m from the point of discharge. Studies revealed that there was negative impact of evaluated temperature on plankton upto 500 m from discharge point
Removal of basic dyes from aqueous medium using a novel polymer: Jalshakti
No full textStudies were carried out to remove basic dyes such as safranine T, methylene blue, crystal violet, light green, brilliant milling violet and patent blue VS from their aqueous solutions using biodegradable polymeric absorbent material, viz., Jalshakti� (JS). Results showed that 93% safranine T, 98% methylene blue and 84% crystal violet were adsorbed on JS relative to their initial concentration
(10 mg L�1). The optimum pH was found to be 6.0 ± 0.5 and smaller size of particle of JS resulted better adsorptive
removal of the dyes. IR spectroscopic and potassium ion release studies revealed that basic dyes were selectively removed through adsorption–ion-exchange mechanism involving carboxylic groups and K+ ions of JS
Application of supported perovskite-type catalysts for vehicular emission control
No full textCatalytic control of auto-exhaust emissions is one of the most successful applications of heterogeneous catalysis, both in
commercial and environmental point of views. Although noble metal-based catalysts have dominated this area, efforts were always
put in towards development of low cost non-noble metal-based catalysts. With the recent need of closed-coupled catalytic
converter, thermal stability requirements have also become more severe, leading to the search for stable catalytic materials. Mixed
oxides, including those perovskite type compounds with ABO3 structure have been extensively studied, mainly for their catalytic
and electrical properties. Low surface area of these catalysts has so far been the most important limitation for their catalytic
applications involving high space velocities, e.g. auto-exhaust catalysis. Various synthesis routes have been earlier attempted to
improve their surface area, yet this was much inferior than the noble metal catalysts, dispersed on high surface area alumina. The in
situ synthesis of these oxides on alumina is often associated with the formation of undesired phases, due to the reactive nature of
perovskite precursors. However, alumina washcoat, commonly used for improving the surface area of ceramic and metallic catalyst
supports, can be modified for perovskite applications. In situ synthesis of stabilized perovskites on modified alumina-washcoated
supports offer high surface area and excellent catalyst adhesion. Although, it is difficult to ascertain the presence of pure perovskite
type materials on support, such improved synthesis has resulted in remarkable improvement in their catalytic activity for their
applications in auto-exhaust catalytic converters. This review presents our work on synthesis of various improved perovskite-type
mixed oxides supported on modified alumina-washcoated cordierite honeycomb, their characterization, and detailed catalytic
evaluations for possible application in automobile pollution control
Temperature-Induced Stress on Growth and Expression of Hsp in Freshwater alga Scenedesmus quadricauda1
No full textObjective To investigate the impact of various levels of sublethal temperature (26'C, 31'C, 33'C, 36'C, and 39'C) on
growth and heat shock protein (hsp) expression in freshwater green alga Scenedesmus quadricauda. Methods Impact of selected levels of temperature on growth rate (based on optical density), population count, chlorophyll-a and biomass of the alga was evaluated in artificial growth medium for 19 days. To determine the induction of hsp in the alga, it was exposed to selected temperature levels for 3 h and further kept for 6 h at culturing condition at 26'C. Induction of hsp was confirmed by imrnuno-detection followed by SDS-polyacrylamide gel electrophoresis. Results The selected growth parameters such as growth rate, population count, chlorophyll-a and biomass were reduced significantly (P<O.OOl) at 39'C. However, hsp 70 expression was observed only at 39'C. Conclusion Temperature up to 36'C may be considered as the limit of safe exposure for thermal stress for the alga Scenedesmus quadricauda