Preparation of black lyophilic ink using the carbon soot emitted by vehicles

Environmental Science and Pollution Research - The carbon soot is formed as a consequence of incomplete combustion of hydrocarbons and organic matter. It causes respiratory diseases like lung...     

Electrolytic removal of Rhodamine B from aqueous solution by peroxicoagulation process

Peroxicoagulation treatment of aqueous solution containing hazardous dye, Rhodamine B, with commercially available graphite as cathode and iron as anode has been studied. The effect of various operational parameters such as solution pH, applied voltage, electrode area, other ions, etc. on the dye removal was investigated. The experimental result showed that pH-regulated peroxicoagulation system is an efficient process for the dye removal. Ninety-five percent of the dye was removed after 180 min of electrolysis. Anions such as carbonate, bicarbonate, chloride and sulphate negatively affected the efficiency of peroxicoagulation system. From the present study, it can be concluded that peroxicoagulation process is an efficient tool for dye removal from aqueous solution.     

Freshwater lakes--a potential source for aquaculture activities--a model study on Perumal Lake, Cuddalore, Tamil Nadu

The freshwater Perumal lake located at Cuddalore was assessed for its suitability and potential for aquaculture practices. Various hydrobiological parameters determined reveals that the various physicochemical characteristics are with in normal range of values. The DO level, BOD and COD values determined in the lake revealed the consequences of community activities and pollution possibilities. The primary productivity data revealed maximum productivity during March which infer that the lake is unaffected by anthropogenic disturbance and community contamination. The bacterial count remained higher during the monsoon periods, which characterize profuse rainfall and storm water discharge into the lake. The microfauna includes zooplankter such as cladocerans, copepods, rotifers and ostracods. Benthos include carps, catfishes, mullets and prawns. The above study revealed that the various parameters in the lake conform to the levels suited for freshwater fish culture and represents a resource for scientific management.     

Chemometric studies of water quality parameters of Sankarankovil block of Tirunelveli, Tamilnadu

The fluoride concentration in ground water was determined in Sankarankovil block of Tirunelveli district of Tamilnadu (India) where it is the only source of drinking water. Various other water quality parameters such as pH, electrical conductivity total hardness and total alkalinity as well as calcium, magnesium, carbonate, bicarbonate and chloride concentrations were also measured. A systematic calculation of correlation coefficient among different physico-chemical parameters was performed. The analytical results indicated considerable variations among the analyzed samples with respect to their chemical composition. Majority of the samples do not comply with Indian as well as WHO water quality standards. The fluoride concentration in the ground water of these villages varied from 0.66 to 3.84 mg l(-1), causes dental fluorosis among people especially children of these villages. The high and low fluoride containing areas were located using isopleth mapping technique. Overall water quality was found unsatisfactory for drinking purposes without any prior treatment except at few locations out of 50 villages.     

Sediment texture and nutrients of Arasalar estuary, Karaikkal, south-east coast of India

Sediment samples were collected for texture, composition and nutrient such as organic carbon, total nitrogen and total phosphorus for a period of two years from three stations in Arasalar estuary. The sediment temperature, pH and nutrients were higher during summer season and lower during monsoon season. At station 1, sediment texture was loamy sand during summer and premonsoon season. At station 2, clay type soil was recorded. Whereas, at station 3, clay was observed in summer and premonsoon and then it shifted to sandy loam type soil during monsoon. Sediment nutrients were lower than that of values of various ecosystem of India.     

Degradation of dyes from aqueous solution by Fenton processes: a review

Several industries are using dyes as coloring agents. The effluents from these industries are increasingly becoming an environmental problem. The removal of dyes from aqueous solution has a great potential in the field of environmental engineering. This paper reviews the classification, characteristics, and problems of dyes in detail. Advantages and disadvantages of different methods used for dye removal are also analyzed. Among these methods, Fenton process-based advanced oxidation processes are an emerging prospect in the field of dye removal. Fenton processes have been classified and represented as “Fenton circle”. This paper analyzes the recent studies on Fenton processes. The studies include analyzing different configurations of reactors used for dye removal, its efficiency, and the effects of various operating parameters such as pH, catalyst concentration, H₂O₂ concentration, initial dye concentration, and temperature of Fenton processes. From the present study, it can be conclude that Fenton processes are very effective and environmentally friendly methods for dye removal.     

Effect of Relative Humidity on Electrically Stimulated Filter Performance

This work investigates the effect of relative humidity (RH) on the performance of three electrically stimulated filter designs, with and without prechargers. Two different filter media were used: cellulose paper (relatively conductive) and fiberglass paper (relatively nonconductive). Designs with electrodes contacting either of the two filter media are shown to draw currents, exponentially increasing with RH. In contrast, a noncontacting, air gap, electrode design has been shown to be significantly less sensitive to RH. Further, the air gap or noncontacting electrode behaves differently than insulated electrodes. The noncontacting electrode does not exhibit the polarizing or field cancelling effect of insulated (coated) electrodes. This is probably due to a small but finite amount of ionization at the sharp electrode perforations.     

Diagnosis and Repair of Excessively Emitting Vehicles

Abstract

Between 1991 and 1993, the California Air Resources Board (CARB) selected 1,115 vehicles from all across the South Coast Air Basin to evaluate the effectiveness of the state's existing biennial motor vehicle Inspection/Maintenance (I/M) or Smog Check program. The vehicles were chosen to represent the population of cars that "should fail" properly conducted inspections. The cars were emissions-tested at baseline and sent undercover to licensed I/M garages throughout the basin. Federal Test Procedure (FIT) emissions were measured again for cars that were repaired. In the second year of the study, the vehicles that could be reproduced were tested at the CARB to measure the level of emissions deterioration and any underhood changes in emission control systems. In the third year, the cycle of emissions testing and undercover inspections and repair was repeated.

This paper uses data from the study to explore the relationships between super emitting vehicles (defined here as vehicles whose emissions are several times California certification standards) and diagnostics and repair of their underhood emissions control systems. Also examined is their appearance and improvement during a three-year period that includes two cycles of inspection and repair. An important finding is that once normalized to account for differences in certification standards, the super emitting vehicles do not have a unique signature in terms of their underhood emission control system failure modes, mileage, or age, when compared with the average vehicle expected to fail a Smog Check inspection. However, they are more likely to be identified, diagnosed, and repaired effectively than other vehicles, although they continue to reappear over time.     

Fluoride sorption by treated fly ash: kinetic and isotherm studies

High fluoride levels in drinking water have become a critical health hazard. In the present study, the performance of magnesia-loaded fly ash adsorption in the removal of fluoride from aqueous solution was investigated in a batch study. The effect of contact time, dosage, pH, temperature and agitation speed was studied at different values. The maximum removal efficiency was 88 % at 150 min. The effective dose of adsorbent was found to be 2.5 g/l. The optimum pH was found to be at pH 4. Kinetic studies and isotherm studies were also performed to understand the ability of the adsorbents. The monolayer adsorption capacity determined from the Langmuir adsorption equation was found to be 11.61 mg/g. The kinetic measurements suggested the involvement of pseudo-second-order kinetics in adsorption and were controlled by a particle diffusion process. Overall, the results of this study suggest that magnesia-loaded fly ash is an environmentally friendly, efficient and low-cost adsorbent, useful for the removal of fluoride from aqueous solution.     

WELFARE IMPLICATIONS OF TUBEWELL IRRIGATION IN BANGLADESH1

ABSTRACT: This paper investigates and estimates the welfare loss due to monopoly in tubewell irrigation water market in Bangladesh. In this context, an attempt has been made to evaluate the efficacy of the landless irrigation groups. Using cross-sectional data and regression analysis, cost and demand functions for irrigation water are estimated. The study demonstrates the relatively superior performance of the landless groups in terms of economic efficiency in shallow tubewell irrigation operation, in comparison to irrigation operation by the landowners.