Effect of Molecular Properties on the Photocatalytic Degredation Rates of Pyridazine

Gulsen A. and Gurkan Y. Y.

In this study, with the intention of determining the primary intermediates, the photocatalytic degradation reaction of pyridazine which has been accepted as the pollutant was modelled. Geometry optimizations of the reactants, the product radicals, the pre-reactive and the transition state complexes were performed for all the possible reaction paths. The Hartree-Fock calculations were carried out on HF/6-31G* basis set. Based on the results of the quantum mechanical calculations, the rate constants for all the possible reaction paths were calculated by means of the Transition State Theory. The difference in the rates of reaction paths were explained in terms of the presence of hydrogen bonds in the transition state complexes.

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Comparison of corrosion resistant behavior of Zirconium and Tin based thin films on steel in 3.5% NaCl

Patel Niketan S.

The corrosion behavior of steel coated with Zr-N and Ti-N films of varying thickness 1.5µ, 2µ, 2.5µ, 3µ and 4µ, deposited by cathode arc evaporation PVD technique has been studied by potentiodynamic corrosion test using 3.5 % NaCl solution. The electrochemical results obtained have been correlated to structural defects studied by scanning electron microscopy. The phase analysis of coating was carried out using XRD. The results of both Zr-N and Ti-N films has been compared and reported. The results clearly indicated that both types of coatings provide sufficient corrosion protection and in both cases corrosion resistance is higher for coating of 3.0μ and 4.0μ thickness compared to the less thick 1.5μ and 2.0μ.

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Studies of DeNOx catalytic activity over some transition metal oxide catalysts

Sakhre D. K., Sinha S. L. and Singh S. P.

NOx pollution due to increased motor vehicle use in urban cities of India is today’s major environmental concern. Catalytic converters with noble metal catalyst are common for petrol driven vehicles for reducing CO, HC and NOx; but for Diesel driven vehicles and especially for NOx removal, catalytic converters are not common. There are several techniques to control NOx emissions from diesel exhaust, but After Treatment Technique has better advantages and more convenient. To study the SCR (Selective Catalytic Reduction ) of NO (Nitric Oxide) by transition metal catalysts; a series of catalyst of 2%, 5% and 8% wt% loading of Silver, Iron, Chromium and Vanadium over γ-alumina support have been prepared, characterized and tested in a stream of synthetic diesel exhaust gas which contains propane as reducing agent. The catalysts have been characterized by BET surface area, pore volume and XRD techniques. The catalytic activity has been tested between 1000-500oC reaction temperatures and GHSV 6,000 h-1 to 18,000 h-1. It was found that 5% Silver catalyst has given maximum 43% and 5% Iron catalyst has given maximum 39% NO conversion between 2000-4000C reaction temp- eratures. The study suggests that low cost silver and iron based transition metal oxide catalysts can be used for removal of NOx pollution from diesel exhaust gas.

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Correlation between Soil Physico-chemical Properties and Heavy Metals Contents in Farmland around Scale Pig Farms, Nanchang City

Zhang Qiugen

The farmland soils surrounding scale pig farms in Nanchang were sampled and the content of soil heavy metals and its physical and chemical properties were measured. The Pearson Correlations between the content of heavy metals and soil physicochemical property were analyzed through SPSS 18. The farmland soil was generally acidic; the content of soil organic matter was above the third grade; the content of available nitrogen was between the grades fifth and sixth and the content of available phosphorus was classified as the rich grade. The farmland soils surrounding scale pig farms were suitable for crop growing. The average content of As, Cr, Cu and Zn was within the standard while Cd, Ni and Pb was out of the standard. The competitive pollution index was greater than 1 which showed that the farmland soils were in slightly polluted grade. Soil available nitrogen, available phosphorus and soil oxidation-reduction potential were negatively correlated while soil available nitrogen and available phosphorus were positively correlated. The correlation among heavy metals As, Cd, Pb, Cu and Zn was highly significant or significant, but the correlation among Cr, Ni and other heavy metals was not relevant. The available phosphorus and oxidation-reduction potentials have an obvious influence on the distribution of heavy metals. The available nitrogen has a non-significant influence on the distribution of heavy metals while the soil water content, pH and soil organic have no influence on the distribution of heavy metals.

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Adsorptive capacity of thermally treated clay from northwest Algeria

Benhebal Hadj, Kadi Samir and Chaib Messaoud

The present investigation assessed the effect of the heat treatment of a clay material on the adsorption of phenol from aqueous solution. The natural material used is a clay mixture composed mostly of kaolinite and illite and which has been heat-treated at 500, 650 and 800°C. The raw and heated clay was subjected to different techniques of characterization as X-ray diffraction, Scanning Electron Microscopy (SEM), Thermal analysis (TGA) and Specific Surface Area (BET). Results obtained at different temperatures and concentrations of phenol show the efficiency of heat treatment on the sorption capacity of adsorbent materials.

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Greener Synthetic Route to Some 2,5-Disubstituted-1,3,4-Oxadiazoles: An Efficient, Rapid and Solid Phase Approach

Kumar Mohit, Kumar Vinod and Kumar Sunil

Today, use of greener approaches in the field of chemical synthesis by inventing novel, environmentally and ecologically benign reaction conditions has become an efficient alternative that can eradicate future problems in the chemicals production. Herein, we report a green, rapid, efficient and solid phase synthesis of 2,5-disubstituted-1,3,4-oxadiazoles in which various benzoyl hydrazones were ground with diacetoxyiodobenzene under environmental friendly conditions. All compounds were obtained in excellent yields and characterized on the basis of their melting points, IR and 1H NMR spectral data.

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Adsorption of methylene blue dye on surface modified Activated carbon

Takute Sapana, Singh Shripal and Yenkie M. K. N.

In present work adsorption studies of methylene blue dye on commercially available activated carbons Filtrasorb-400 (F400) and Hydraffin UV 43 were studied. The surfaces of Activated carbons were modified using sodium dodecyl sulphate. The modified activated carbons were characterised for proximate and ultimate analysis, iodine number, N2-BET surface area and pore volume. The adsorption studies on different temperatures: 25,30 35,40,45 and 500C, pH: 3, 5, 6, 7, 8, 9, 10 and 11 adsorption doses of carbon 0.001, 0.005, 0.01, 0.015, 0.020, 0.025 and 0.030mg in 50ml MB solution were studied. Adsorption results show that percent removal of methylene blue increases with the increase in temperature, pH and adsorbate dose in the present study. The data were analyzed using Langmuir and Freundlich adsorption isotherms. It has been observed that data was best fitted in Langmuir adsorption model. The adsorption potential of modified and unmodified activated carbon for the removal of methylene blue from aqueous solution was investigated and it was observed that modified activated carbon has better adsorption capacity than unmodified activated carbon.

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Solvent free synthesis, characterization and DNA photocleavage study of some first transition series metal complexes of cyanoacetohydrazone Schiff’s bases

Pal R., Kumar V., Gupta A. K., Beniwal V. and Gupta G. K.

The solvent free synthesis of metal complexes of two tridentate Schiff’s bases, Salicylidene-N-cyanoacetohydrazone (CNL1) and 2-Hydroxy-l-benzilidene-N-cyanoacetohydrazone (CNL2) with Co(II), Ni(II), Cu(II), Zn(II) has been achieved successfully under mild reaction conditions. Among synthesized compounds tested for their DNA photocleavage potential using plasmid DNA, metal complexes were found more potent as compared to ligand under the identical experimental conditions.

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Structure Reactivity of Oxidation of Unsaturated Alcohols by Quinaldinium Chlorochromate

Sekar K. G. and Palanivel V.

The kinetics of oxidation of unsaturated alcohols (Allyl alcohol, Crotyl alcohol, Cinnamyl alcohol) by quinaldinium chlorochromate has been studied in aqueous acid medium at 313 K. Unsaturated alcohols were converted to the corresponding acrolein, crotonaldehyde and cinnamaldehyde. The order with respect to oxidant and hydrogen ion concentration is found to be one and fractional with respect to substrate. The decrease in dielectric constant of the medium increases the rate of the reaction. Increase in ionic strength by the addition of sodium perchlorate has no effect on the rate constant. There is no polymerization with acrylonitrile. The reaction has been conducted at four different temperatures and activation parameters were calculated. From the observed kinetic results, a suitable mechanism consistent with rate law has been proposed. The relative reactivity order was found to be Cinnamyl alcohol > Crotyl alcohol > Allyl alcohol.

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Preparation of collagen-elastin hydrolysates from cattle tendons: Preparation conditions

Mokrejs P., Janacova D., Svoboda P. and Cermak R.

This study deals with preparing collagen-elastin hydrolysates from cattle tendons through a 3-stage process. In the 1st stage, tendons are processed in an acidic, neutral or alkaline environment which produces their swelling. In the 2nd stage, a suitable proteolytic enzyme acts in neutral environment which leads to disrupt bonding interactions of collagen and elastin. In the 3rd stage, hydrolysate is extracted at elevated temperature from material so prepared. Variables under study were the environment in 1st stage processing (pH 4-11), duration (2-14 min) and temperature (60-100 oC) in 3rd stage processing on process efficiency (hydrolysate yield). Tests are planned and evaluated by the method of statistic factor experiments. Maximum process efficiency (76 %) was found with tendons treated in an alkaline environment. Prepared hydrolysates of collagen-elastin type, light-yellow powder, may be employed in cosmetics or the foodstuffs industry.

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Influence of Centella Asiatica Leaves Extracts on Corrosion Inhibition of Aluminium in Alkaline Solution

Lakshmi Prabha K. and Rajam Shameela

The effect of centella asiatica leaves (CAL) extract on the corrosion inhibition of aluminium in 1N NaOH solution was studied using chemical and electrochemical techniques. It was found that the inhibition efficiency increased with the increase in the concentration of centella asiatica extract upto 1000 ppm. Beyond this concentration there is no improvement in the inhibition efficiency. The potentiodynamic polarization studies reveal that CAL extract acts as a mixed type inhibitor. Adsorption of CAL extract on aluminium surface follows Langmuir adsorption isotherm. A good agreement was observed between the results obtained in non-electrochemical and electrochemical methods. The protective film formed on the surface of aluminium was confirmed by Scanning Electron Microscope studies.

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Effect of Heavy Metals and Organic Pollutants on Antioxidant Enzyme Activities in zebra fish by polyacrylamide Gel electrophoresis

Zhang Qiugen, Chen Suhua and Deng Fang

The potential utility of antioxidant enzyme activity was evaluated as indicators of exposure to heavy metals and organic pollutants in aquatic organisms. The effect of heavy metals and organic pollutants on antioxidant enzyme activity of zebrafishzebra fish was studied. The trends of superoxide dismutase (SOD) and catafase (CAT) activity in zebrafishzebra fish under after exposure to heavy metals and organic pollutants for different time were analyzed by polyacrylamide gel electrophoresis (PAGE) technique. The brightness of bands in the polyacrylamide gel electrophoresis is almost consistent with the trends of antioxidant enzymes (SOD and CAT) activity in zebrafishzebra fish, namely, the greater was brightness of the bands was, the stronger was activity of SOD and CAT was, indicating PAGE is an effective technique to evaluate the antioxidant enzyme activity. Moreover, the results showed that the exposure time and concentrations of pollutants have a great effect on the SOD and CAT activity in zebrafishzebra fish, . and the dDose-response relationship between SOD/CAT activity and heavy metals or organic pollutants was established.

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Application of carboxylic acids in photo-Fenton-like systems for the removal of contaminants

Danna Zhou, Wenyu Huang and Dandan Xu

Advanced Oxidation Processes (AOPs) using hydroxyl radical (HO•) have been successfully applied in the oxidative removal of organic pollutants in wastewater. Fenton or Fenton-like systems, which are AOPs that employ hydrogen peroxide (H2O2) and iron species [Fe(II) or Fe(III)] under acidic conditions (pH  3.0), have been extensively studied over the last two decades. However, such systems have low efficiency at neutral pH mainly because of the presence of insoluble forms of Fe(III) or Fe(II) under this condition. These species lead to very low yield of HO• in the presence of H2O2. Carboxylic acids can complex with and stabilize Fe(III) at higher pH. Fe(III)-carboxylate complexes exhibit higher photoreactivity than that of the Fe(III)-OH complex. In this paper, we review the application of carboxylic acids in photo-Fenton-like systems for the removal of contaminants.

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