Mercury fractionation in the sediments of Vembanad wetland, west coast of India

Transformations among different mercury species associated with sediments can have a major effect on the metal's mobility and potential for methylation and hence bioaccumulation. In the present study, various fractions of mercury in the sediments of Vembanad wetland system analysed. Total mercury (THg) concentration in the surface sediment varied from 16.3 to 4,230?ng/g. The results of sequential extraction showed that the major portion of mercury in these sediments existed as elemental form followed by organo-chelated form. The least portion observed was the residual fraction (mercury of natural origin). Even though the percentage of mercury observed in the easily available fractions is relatively small, absolute values of these mobile Hg fractions are quite high due to the very high total mercury values. The fractionation of mercury in the sediment was controlled by the organic matter, sulphur complexes and concentration of THg. The results showed that the bioavailability of mercury is high as the amount of mercury found in the initial three fractions is high, which can also enhance the methylation potential of the Vembanad wetland sediments. The fractionation pattern of mercury also revealed the presence of anthropogenic mercury content in the Vembanad wetland sediments.     

Studies on the utility of plant cellulose waste for the bioadsorption of crystal violet dye

Several synthetic dyes employed in textile and food industries are discharged into aquatic environment. These visible pollutants in water damage environment, as they are carcinogenic and toxic to humans. The use of cost effective and ecofriendly plant cellulose based adsorbents have been studied in batch experiments as an alternative and effective substitution of activated carbon for the removal of toxic dyes from waste water. Adsorbents prepared from sugarcane baggase, were successfully used to remove certain textile dye such as crystal violet from an aqueous solution. The present investigation potentiate the use of sugarcane baggase, pretreated with formaldehyde (referred as Raw Baggase) and sulphuric acid (referred as Chemically Activated Baggase), for the removal of crystal violet dye from simulated waste water. Experiments were carried out at neutral pH with various parameters like dye concentration, temperature, contact time and adsorbent dosage. Efficiency of raw baggase was found better than chemically activated baggase for adsorption of crystal violet dye. The data obtained perfectly fits in the Freundlich adsorption isotherm.     

A comprehensive review of the energy efficiency on nano coated fin and tube condenser

The condenser is a piece of equipment used to effectively transfer heat from water to the environment. The fin and tube condenser is the most commonly used in commercial applications. The improved performance of heat transfer in the fin and tube condenser is a significant area of study all over the world because optimizing the efficiency of heat transfer in the condenser will contribute to enhancing the effectiveness of system performance. The vapor deposition, plasma spray, and thermal spray techniques are being used, and it is determined that a heat transfer enhancing coating improves condenser performance. This review discusses the nanomaterial coating over the fin and tube condenser in detail. The various nanomaterial coatings with various propositions and coating methods had been discussed with the evidence of previous researchers. At a 50-degree inclination angle on the condensate plate, the condensate over the coating surface increases by more than 30%. The thermal properties of the working fluid are improved over the condenser, and the overall effectiveness of the condenser is increased by approximately 40% over the non-coated condenser. A 1% volumetric concentration of Nanoparticles in the coated material achieves a maximum efficiency increase of 78.7%.     

Environmental impacts of perchlorate with special reference to fireworks—a review

Perchlorate is an inorganic anion that is used in solid rocket propellants, fireworks, munitions, signal flares, etc. The use of fireworks is identified as one of the main contributors in the increasing environmental perchlorate contamination. Although fireworks are displayed for entertainment, its environmental costs are dire. Perchlorates are also emerging as potent thyroid disruptors, and they have an impact on the ecology too. Many studies have shown that perchlorate contaminates the groundwater and the surface water, especially in the vicinity of fireworks manufacturing sites and fireworks display sites. The health and ecological impacts of perchlorate released in fireworks are yet to be fully assessed. This paper reviews fireworks as a source of perchlorate contamination and its expected adverse impacts.     

Environmental protection and ecology-Indian experience

An attempt has been made in this paper to highlight some of environmental problems and suggest possible solutions for planning water resources development projects.     

Color removal of monoazo acid dye from aqueous solution by adsorption and chemical coagulation

This communication presents the results of an investigation conducted on color removal from a monoazo acid dye, C.I. Acid Red 88, by adsorption onto coal based sorbents like Lignite coal, Charfines and Bituminous coal and F-400 Activated carbon and by chemical coagulation employing Aluminum sulfate, Ferric chloride, Manganese sulfate, Manganese chloride and Barium chloride.