There are several 100 individual components in every crude oil and the composition of each varies with its origin. Most xenobiotic pollutants can be regarded as substituted (or) modified hydrocarbons. Susceptibility to biodegradation varies with type and size of the hydrocarbon molecule. Fuel and lubricating oil spills have become a major environmental hazard to-date. The extent of hydrocarbon biodegradation in contaminated soils is critically dependent upon three factors: a) the creation of optimal environmental conditions to stimulate biodegradative activity, b) the predominant Petroleum hydrocarbon types in the contaminated matrix and c) the bioavailability of the contaminants to microorganisms.
(8) Ca+ 2H2O → Ca(OH)2+H2……………………. (9) (Mudgal et al., 2007; Rahuman et al., 2006 ; WRC, 2001). d) Chemical precipitation Chemical precipitation is one of the useful chemical treatment to convert hazardous heavy metals to insoluble form prior to disposal to a landfill and less mobile. This technique is applicable to any liquid waste stream that consist of precipitable hazardous constituent. The solubility of toxic metals can be decreased by adjusting pH and this leads to the synthesisation of a precipitate which can be removed by filtration and settling.
The stoichiometric quantity of air is needed to completely burn the fuels. The types of pollutants is also depends upon quality of fuels, volatility and types of minerals and impurity is present in fuels (Pundir 2000). The main factors from automobile exhaust induced toxic to human health and living things are physical and chemical property of pollutants, concentration of pollutants and proportion of population exposed. To controlling the formation of pollutants it is necessary to proper maintain of the vehicles and use a durable, economical, long time stable and easily available catalyst in automobile catalytic converter system. The catalytic converter is a device it placed in the vehicle exhaust pipe for converting HC, CO and NOx into less harmful gas (Satterfield
On the other hand, there are many disadvantages such as the mercury electrodes tend to malfunction because of clogging when mercury is oxidized by air, also toxicity may occur because of the use of mercury, it has a limited potential and a small capillary that can be easily blocked, the oxidation of mercury can easily happen and the mercury used must be highly pure. Types of currents in Polarography: 1 – Direct current polarography In this type a current will flow through a cell containing analyte and a supporting electrolyte, a current voltage curve is obtained by the use of dropping mercury electrode. It gives accurate results for the moderate concentrations but limited application on lower concentrations due to large rhythmic fluctuations. When voltage applied to the cell increases, a small residual current flows until the substances undergo reduction or oxidation. At first the current increases linearly with the voltage then it gradually reaches a limit value.
All isocyanates are toxic, and their toxicity is greater following inhalation than following oral ingestion. MIC is the most toxic member of the isocyanate family. At room temperature, MIC is a colorless liquid. MIC is flammable; its molecular mass is 57.05, specific gravity 0.96 relative to water at 20°C, vapour pressure 348 mm Hg (464 mbar) at 20°C and vapour density 1.97 relative to air. The boiling point of MIC is 39.1°C, which implies that some MIC will vaporize at a room temperature of 23°C and all of it can exist as vapor in Bhopal on certain hot days of the summer.
Non removal of As(III) hence oxidation is required.  3.2.4 Physical removal Some synthetic membranes are permeable to certain dissolved compounds but exclude others. Because of their selective permeability for different compounds, such membranes can act as a molecular filter to remove dissolved arsenic, along with many other dissolved and particulate compounds. High pressures are required to cause water to pass across the membrane from a concentrated to dilute solution. For this reason membrane separation is addressed as a pressure driven process.
Heavy metals refer to any metallic chemical element that has a relatively high density and is toxic or poisonous at low concentrations including Mercury (Hg), Lead (Pb), Cadmium (Cd), Chromium (Cr), Copper (Cu), and Zinc (Zn) (Victor 2013). Heavy metals that contaminate the environment reduced quality of environment that later harm the living organisms. However,
Water pollution caused by heavy metals is a global problem. The discharge of toxic metals into the ecosystem may severely affect the biotic as well as abiotic components of the environment. These metals are generally derived from different industrial activities such as mining, metal finishing, battery manufacturing, electroplating, etc. and are responsible for contaminating the receiving water bodies even when present in trace amounts. This is due to their carcinogenic and toxic properties (ATSDR, 2013).
Introduction Environmental pollution is a multidisciplinary science chemistry, physics, agriculture, life sciences, health , medicine , health , etc. In a broader sense it is the study of the sources, reactions , transport , effects and fate of chemical species in the air, water and soil and the effect of human activity on this. Pollutant means a substance in the environment, greater than the natural abundance due to human activity, which ultimately has a detrimental effect on the environment and so on living organisms and the human race . Examples are- lead, mercury , sulfur dioxide , carbon monoxide , etc. Contaminant : A material that does not occur in nature but that is introduced by human activity on the environment , affecting their composition.
SYNTHESIS AND CHARACTERIZATION OF CERIUM OXIDE NANOCOMPOSITES AND THEIR CATALYTIC APPLICATIONS IN DIESEL SOOT ABATEMENT Introduction:- Air is the most essential constituent of environment for the sustenance of life on earth. In pure air, the proportion of different constituents like oxygen, nitrogen and other gases is fixed and definite. Overall health of our body and mind heavily depends upon the amount of pure, fresh air breathed. But, now a day’s pollution is the biggest threat to life. Major part of environment is getting polluted because of the mixing of particulate matter (PM), nitrogen oxides (NOX), & volatile organic compounds (VOC’s) produced by emission from diesel engines.