New catalyst comprising Silicotungstic acid and MCM-22 for degradation of some organic dyes

A heterogeneous catalyst comprising Keggin type polyoxometalate, silicotungstic acid (SiW₁₂), and MCM-22 was synthesized using wet impregnation method and characterized by acidity measurement, BET, FT-IR, XRD, and SEM. Their catalytic activity was evaluated for the degradation of cationic organic dyes like methylene blue (MB), crystal violet (CV), and an azo dye Chryosidine Y (CY) in an aqueous solution. The experimental parameters such as catalyst amount, initial dye concentration, and contact time were studied for the degradation of dyes, and it was found that the cationic dyes like methylene blue and crystal violet show better activity as compared to azo dye Chryosidine Y. This may be attributed to better electrostatic interaction of these cationic dyes with the residual negative surface charge of the catalyst, due to presence of SiW₁₂ ion as it is rich in surface oxygens and surface hydroxyl groups. The control experimental results showed that the presence of SiW₁₂ at the surface of MCM-22 promoted the degradation reactions, and presence of multiple W–O bonds in polyoxometalate also played a key role in this reaction. The catalyst exhibits recycling ability without any significant loss in activity up to four cycles.

     

Environmental training and cleaner production in Indian industry—A micro-level study

An attempt has been made to analyze various types of organizational training imparted in Indian Industries while implementing cleaner production. The study was carried out in two industrialized states of India, namely Maharashtra and Gujarat. with participation of eight firms from each state. The various sources of training for the Indian industries have also been studied. A case study each from the two states, viz. Maharashtra and Gujarat have been presented in this paper. It is found that more than half of the industrial units have given importance to various kinds of training during the implementation of cleaner production. When it comes to training in environmental management system (EMS), nearly half of the firms have gone in for it. Among the sources of training, the most useful training was the training imparted by in-house staff and on-the-job training. Lastly, suppliers of cleaner technologies seem to have also played an active role in training as revealed by few of the participating units     

Influence of plant growth stage and season on the release of root phenolics by mulberry as related to development of phytoremediation technology

The phenolics released by red mulberry (Morus rubra L.) roots at different growth stages within a season were quantified and the makeup of phenols analyzed by reverse-phase high performance liquid chromatography (RP-HPLC). The data show that total phenols released into the soil solution increased continuously from an early vegetative stage to leaf senescence, indicating their accumulation in the rhizosphere. From the RP-HPLC analysis of the butanol-extractable phenolics at various growth stages, there appears to be a massive release of an assortment of less polar phenolics into the rhizosphere at the end of the season accompanying leaf senescence. The rhizosphere phenolics may create an environment suitable for the biodegradation of recalcitrant environmental pollutants, by selectively fostering the growth of some, while inhibiting the growth of other microbes.     

Gamma dose measurement in dwellings of Agastheeswaram Taluk of Kanyakumari district, lying 30 km Radius from Kudankulam nuclear power plant site

Most of the building materials contain naturally occurring radioactive elements, the most important of which are potassium ⁴⁰K and the members of two natural radioactive series, which can be represented by the isotopes of thorium ²³²Th and Uranium ²³⁸U. The presence of these radioisotopes in the materials causes external exposure to the people who live in the building. In addition, the disintegration of Uranium ²³⁸U increases the concentration of radon gas ²²²Rn and of its daughters in the house. So a systematic indoor gamma dose measurement has been performed in the dwellings of Agastheeswaram Taluk of Kanyakumari district, which is lying within the 30 km radius from the upcoming Kudankulam nuclear power plant site. The geometric mean of annual absorbed dose from gamma radiation in dwellings has been found to be 278 nGyh⁻¹. The seasonal variation of indoor gamma dose measurements has also been studied. Significant differences have been observed in dwellings built of different materials such as concrete, tiled, etc.     

Studies on the sorption and desorption characteristics of Zn(II) on the surface soils of nuclear power plant sites in India using a radiotracer technique

Zinc adsorption was studied in the soils of three nuclear power plant sites of India. 65Zn was used as a radiotracer to study the sorption characteristics of Zn(II). The sorption of zinc was determined at 25 and 45 degrees C at pH 7.8+/-0.2 in the solution of 0.01 M Ca(NO3)2 as supporting electrolyte. The sorption data was tested both in Freundlich and Langmuir isotherms and could be described satisfactorily. The effect of organic matter and other physico-chemical properties on the uptake of zinc was also studied in all the soil samples. The results showed that the cation exchange capacity, organic matter, pH and clay content were the main contributors to zinc sorption in these soils. The adsorption maximum was found to be higher in the soil on Kakarpara Atomic Power Plant sites soils having high organic matter and clay content. The zinc supply parameters of the soils are also discussed. In the desorption studies, the sequential extraction of the adsorbed zinc from soils showed that the diethylene triamine penta acetic acid extracted maximum amount of adsorbed zinc than CaCl2 and Mg(NO3)2. The zinc sorption on the soil and amount of zinc retention after extractants desorption shows a positively correlation with vermiculite and smectite mineral content present in the clay fraction of the soil. The amount desorbed by strong base (NaOH) and demineralised water was almost negligible from soils of all the sites, whereas the desorption by strong acid (HNO3) was 75-96% of the adsorbed zinc.     

Major Ionic Composition of Aerosol, Rainwater and its Impact on Surface and Sub-surface Waters, in and Around Mangalore, West Coast of India

Mining activities in Rakha copper mine (Jharkhand, India) were ceased in the year 2001, leaving a huge amount of untreated tailings in the nearby tailings pond. The copper tailings contained high concentrations of heavy metals (total Cu, Ni concentrations 1779, 564 mgkg⁻¹, respectively), and low contents of major nutrient elements and organic matter. Tailings are often very unstable, and a potential vegetation cover may reduce the erosion or immobilize the toxicants to surrounding environment by phytostabilization. However, high shoot concentrations of elements might disperse them and could be harmful to grazing animals. The objective of this study was to find out which of the three properties; low-accumulation, root accumulation or shoot accumulation of elements (Cu, Ni, Mn, Zn, Pb, Cd and Co), occur in the semi aquatic species Ammania baccifera growing on copper tailings. Roots of this species accumulated high levels of Cu, even more than 1000 mg kg⁻¹, DW. Metals accumulated by A. baccifera were mostly distributed in root tissues, suggesting that an exclusion strategy for metal tolerance widely exists in them. Thus, establishment of such plant on copper tailings can be a safe method to stabilize the metals.     

Methane and carbon dioxide emissions from closed landfill in Taiwan

The atmospheric concentrations and emission rates of CH(4) and CO(2) were studied at three sites of the Fu-Der-Kan closed landfill and after as the multi-use recreational park in northern Taiwan. Atmospheric CH(4) and CO(2) concentrations of closed landfill were 1.7-4.6 and 324-409ppm, respectively. CH(4) and CO(2) emission rates ranged from 8.8 to 163mg m(-2)h(-1) and from 495 to 1531mg m(-2)h(-1), respectively. Diurnal variation was noted with higher values at night than those in daytime. After creation of the park, atmospheric CH(4) and CO(2) concentrations were 1.8-3.1 and 332-441ppm, respectively. CH(4) and CO(2) emission rates ranged from -1.1 to 2.3mg m(-2)h(-1) and from -135 to 301mg m(-2)h(-1), respectively. There were no notable diurnal variations in either atmospheric concentrations or emission rates.     

An analysis of cleaner production and its impact on health hazards in the workplace

The main focus of this paper is to bring out the cost effectiveness of cleaner production and the role played by cleaner production in minimizing the health hazards of pollutants in the workplace. Improvement in workplace health hazards due to implementation of cleaner production has been illustrated with the results of the study. This study was carried out in 16 Manufacturing units in two states of Maharashtra and Gujarat in India. The results clearly shows with the help of cost benefit analysis that cleaner technologies not only add to the bottom line of the company but also minimize exposure to toxic chemicals like Ammonia, phenol, carbon tetrachloride, toxic dust, etc. The main driving forces motivating the firms to go in for cleaner production are evaluated. It is found that in most of the units safety and health factors were ranked as one among the first four driving forces behind implementation of cleaner technologies. The paper ends with recommendations for the promotion of cleaner technologies.     

Seasonal and vertical characteristics of particulate and elemental concentrations along diverse street canyons in South India

Environmental Science and Pollution Research - The impact of street geometries on vertical dispersion of PMs (PM2.5 and PM10) in (1) non-street canyon (NSC), (2) street canyon (SC), and (3) street...