Research Journal of Chemistry and Environment

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Vol. 9(4) December 2005

Completely Biodegradable Foams of Poly(propylene Carbonate) Derived from Carbon Dioxide and Propylene Oxide

L. T. Guan, F. G. Du, M. Xiao1, R. K. Y. Li2 and Y. Z. Meng

Completely biodegradable foams of poly(propylene carbonate) derived from carbon dioxide and propylene oxide were produced using azodiformamide (AC) as chemical blowing agent, and zinc oxide (ZnO) as the activator to lower the decomposition temperature of azodiformamide. Thermogravimetric analysis (TGA) and decomposition behavior of the modified-AC consisting of AC and ZnO were investigated to optimize the composition of foam material. The formulation of the blowing agents, the foaming temperature and the morphology of the produced poly(propylene carbonate) foams were studied accordingly. The results demonstrated that the greatest blowing ratio of 18 can be afforded in case 8phr blowing agent was used at 170oC for 30 min.

Opportunities Afforded by New Generation of Pulsed Radiation Sources in Flash Radition Physics and Chemistry

Vladimir A. Gribkov, Aleksandr Dubrovsky, Marina A. Orlova and Marek Scholz1

The paper discusses new generation of devices irradiating very short high-energy pulses of ionizing radiation. Various perspectives emerged in radiation physics and chemistry owing to appearance of them dictate to use the term “flash radiation chemistry” in its perfect sense only in a particular condition. Viz. two prerequisites (spatial and temporal) must be fulfilled: overlapping of individual effective interaction micro-volumes (e.g. spurs and blobs at water electrolysis) and it has to be realized during a time interval (radiation pulse duration) that is less compared with the corresponding physical-chemical process. Namely in this situation it appears to be possible to change reaction rate, to influence reactions at kinetic level, as well as to realize a number of synergetic (collective) effects. The non-stationery and non-diffusive development of chemical processes has to be counted as an intrinsic feature of the perfect flash radiation chemistry.

UV Photodegradation of Triazine Pesticides and their Metabolites

Šárka Klementov and Vlasta Píšková

UV (254 – 300 nm) photochemical degradation of three chlorotriazine pesticides (atrazine, simazine, propazine) and two atrazine metabolites (desethylatrazine and desisopropylatrazine) was investigated and photolytic rate constants and quantum yields were determined. The rate constants were of the order of magnitude 10-4 s-1 for all the substrates, higher for pesticides and lower for metabolites. The photolysis proceeds via release of Cl- ions and formation of hydroxyderivatives for all substrates. Metabolites are not formed in photolytic reaction. Metal (Fe3+) ions and pH changes do not affect the reaction rate. Humic substances in natural water samples slow down the reaction rate by optical filtration. 1O2 produced by photosensitized reaction in pesticide solutions does not react with triazines.

Studies on Surface Ozone in Chennai

M. Pulikesi, P. Baskaralingam, V. Ramamurthi and S. Sivanesan*

Surface ozone concentrations were measured in October 2004 and in March 2005 at Chennai in Tamilnadu by the UV absorption method. The maximum and minimum hourly surface ozone concentrations were observed during October and March. The hourly average values varied between 1 ppb and 50.27 ppb during the above-mentioned period. The present ozone exposures are lower than the critical levels of U.S EPA standard (120 ppb, maximum 1-h permissible concentration). The ozone concentrations were found to be higher for lower Relative Humidity and during the weekdays.

Phase Equilibrium in the System Ln-Mn-O VIII Ln = Pr and Lu at 1100 °C

Kenzo Kitayama and Takuya Yazaki

Phase diagrams of the Pr-Mn-O and Lu-Mn-O systems were established at 1100°C at the oxygen partial pressures ranging from -log (Po2/atm) = 0 to 13.00 and phase diagrams for the corresponding Ln2O3-MnO-MnO2 system at 1100°C were constructed. Stable Pr2O3, Pr6O11, MnO, Mn3O4 and PrMnO3 phases were found in the Pr-Mn-O system and Lu2O3, MnO, Mn3O4 and LuMnO3 phases were stable in the Lu-Mn-O system. LnMn2O5, Ln2MnO4, Mn2O3 and MnO2 were not found in either system under the present experimental conditions. Nonstoichiometric ranges were found in both LnMnO3 phases with the composition of PrMnO3 and LuMnO3 represented as functions of log (Po2/atm), No/NPrMnO3 = 1.10 x 10–3 (logPo2)2 + 2.34 x 10–2 (log Po2) + 0.1109 and No/NLuMnO3 = -2.89 x 10–4 (log Po2)2 + 7.11 x 10-4 log Po2 + 1.09 x 10–2. Activities of the components in solid solutions were calculated from these equations. Lattice constants of PrMnO3 and LuMnO3 quenched at different oxygen partial pressures were determined and compared with previous values. The standard Gibbs energy changes of the reactions appearing in the phase diagrams were also calculated. The relationship between the tolerance factor (t) of LnMnO3 and the D °C values of the reaction, 1/2 Ln2O3 + MnO + 1/4 O2 = LnMnO3 , was plotted on the previous figure and shown graphically. A general equation of Gibbs energy, DG0 (hexa) = -6.426 x 102 t + 5.406 x 102 for the above chemical equation of the hexagonal LnMnO3 was obtained. DG0 value of LuMnO3 for the transition from a hexagonal to a orthorhombic system was obtained and added to our previous data obtained at 1100°C.

Biochemical Composition of Some Marine Copepods

V. Ashok Prabu, P. Perumal and M. Rajkumar

Percentage composition of protein, lipid, carbohydrate and fatty acid of 4 species of copepods collected from the inshore waters of Cuddalore coastal waters were estimated following standard methodologies. Nutritional quality of live feeds used in aquaculture is an important factor for survival and optimal growth of larvae of finfishes and shellfishes. Copepods are considered to be a valuable source of protein and an alternative ingredient to the more expensive Artemia salina. Of the principal biochemical constituents, protein formed the major component followed by lipid and carbohydrate. Protein content showed slight variations and ranged between 66.83 and 69.92%. The carbohydrate content varied from 7.31 to 9.20%. Higher accumulation of lipids in copepods during phytoplankton blooms could be an adaptative phenomenon and may function as metabolic reserve and insulation layer. The results, in general, supported the view that protein may function as a metabolic reserve in copepods and that the availability of a constant supply of food may render large amount of lipid storage unnecessary in tropical copepods. The arachidonic acid (15.48%) and DHA (10.74%) contents were found to be maximum in cyclopoid copepod, Oithona rigida compared to other copepods. The present study also suggests that further research is needed on the chemical characterisation of copepods, the developmental stages of copepods based on dry diets and the effects of the replacement of fish meal with copepod meal for commercial aquaculture species.

Removal of Cadmium from Aqueous Solutions by Crab Shells

Kenneth L. Dorris and Shyam S. Shukla

A waste from the seafood industry, crab shells, has been used as a wastewater filter for treating metal ions in water. Chitosan, obtained from partially converted crab shell waste was used to remove cadmium from water. The metal uptake by partially converted crab shell waste was successful, rapid; and the effect of pH was not prominent. The sorption occurred primarily within five minutes. The adsorption observed behavior was very similar for both static and stream methods. The sorption mechanism appears to be quite complicated and cannot be adequately described by either the Langmuir or Freundlich theories. Various anions, chloride, bromide, fluoride, acetate, sulfate, nitrate and phosphate were found to have a very small effect on the capacity of the crab shells for uptake of cadmium. Advantages of chitosan include availability, low cost, and high biocompatibility.

Heavy Metal Analysis in Raphanus Sativus and Environment

T.I. Khan, Mayanka Kala and Richa Marwari

This paper contains results of a study carried out in agricultural fields of Sanganer town. This town is situated about 20kms away from the city center, Jaipur. In the study area (Amanishah Nalla Sanganer, Jaipur) vegetables are grown in the fields receiving sewerage and textile waste water. Water, soil and crop plant (samples) were collected from the agricultural fields of “Sanganer” for analysis. Waste water (from Amanishah Nalla) used in irrigation of agricultural fields of Sanganer town was found to contain 2.52 mg/l of Zinc, 1.95 mg/l of Copper, 1.12 mg/l of Nickel, 0.72 mg/l of Cadmium, 1.52 mg/l of Chromium, 2.11 mg/l of Lead and 0.99 mg/l of Cobalt as the highest amount of respective heavy metals. Soil from agricultural fields contained 2.91 mg/g of Zinc, 2.23 mg/g of Copper, 1.31 mg/g of Nickel, 1.11 mg/g of Cadmium, 2.13 mg/g of Chromium, 3.12 mg/g of Lead and 1.10 mg/g of Co as the highest amount in the agricultural fields of Sanganer. Raphanus sativus (plant material) grown in the study area was analyzed for heavy metal contents. Plant material (root, stem or leaves) contained 1.25 mg/g of Zinc, 0.835 mg/g of Copper, 0.709 mg/g of Nickel, 0.359 mg/g of Cadmium, 0.70 mg/g of Chromium, 1.019 mg/g of Lead and 0.376 mg/g of Cobalt as the highest amount of heavy metals. Consumption of such vegetables (grown in agricultural fields containing polluted soil and waste water) by human beings containing heavy metals in higher concentration is a matter of concern since it may cause health hazards associated with different heavy metals.

Thermodynamics of Micellization and Interfacial Adsorption of Polyoxyethylated Octyl Phenol in 0.01 M NaCl at Air-water Interface

Pragnesh N. Dave, Narsidas J. Parmar and Shakil S. Sait

The surface properties of a polyoxyethylated octyl phenol [C8H17-O(CH2CH2O)10-H] has been studied through surface tension measurements. The surface excess (G) and the corresponding interfacial parameters have been computed. The Gibbs free energy, enthalpy and entropy of micellization (DGm0, DHm0, DSm0) and of adsorption at air-water interface (DGad0, DHad0, DSad0) have also been evaluated. An enthalpy-entropy compensation effect has been examined with an isostructural temperature of 290 K for both the micellization and interfacial adsorption processes. The minimum area per surfactant molecule and critical micellar concentration divulge that both hydrophobicity and steric constraints of the surfactant play a pivotal role in micelle formation.

Spectral Characterization of Main Anthraquinone in Himalayan Rhubarb (Rhehum Emodi)

Prem Raj, Ranjan Kumar and B.N. Singh

The main anthraquinone from roots of Himalayan rhubarb was isolated. Structure of each isolated fraction was verified from previously reported data for rhubarb. 1,8-dihydroxy-3-methyl anthraquinone, 1,8-dihydroxy-3-methyl 6-methoxy anthraquinone, 1,3,8-dihydroxy-6-methyl anthra-quinone was main anthraquinone. The structure was verified after spectral characterization of each fraction using UV-Vis, IR, FAB-MASS and 1HNMR spectroscopy.

Bio-Methanation of Sewage by UASB Reactor for Small Community

Anand Vashi

A pilot-scale Upflow Anaerobic Sludge Blanket (UASB) reactor was operated over 250 days treating part of sewage from existing sewage treatment plant at Singanpore site, Surat. The reactor was designed to handle sewage flow of about 350 PE. The average influent organic pollution of sewage amounted to 679.67 (134.93) mgCODtot/L with extreme values for the minimum and maximum, i.e. 432 and 1224 mgCODtot/L respectively. The average removal efficiency (with standard deviation in brackets) of CODtot, and TSS was 63.12(9.33)%, and 70.47 (9.67)% respectively. The temperature range of the sewage was typical for tropical regions, viz. 25-30°C. The average biogas yield was obtained about 0.27 NM3CH4/kgCOD rem.

Thermodynamics and Kinetics of Tert-butyl Alcohol Degradation: A Density Functional Theory Study

Krishna L. Bhat, William H. Brendley, Jr. Mendel Trachtman and Charles W. Bock

Thermodynamic and kinetic parameters are reported for a variety of the underlying chemical reactions potentially involved in the degradation of tert-butyl alcohol (TBA). These parameters have been calculated using density functional theory and, wherever possible, are compared with the corresponding data obtained for the analogous reactions of the ubiquitous fuel additive methyl tert-butyl ether (MTBE). These calculations confirm that uncatalyzed, unimolecular decompositions and uncatalyzed hydrolysis reactions of TBA proceed very slowly under ambient conditions. On the other hand, the acid catalyzed conversion of TBA to isobutene is known to be an important mechanistic pathway for this alcohol, and simple model calculations suggest that this reaction proceeds rapidly by forming a tert-butyl carbonium ion intermediate. In the presence of a hydroxyl radical source, the dominant first step in the degradation of TBA is hydrogen abstraction at one of the methyl groups or at the hydroxyl moiety.

Antibacterial Study of the Mannich Base, N-(1-morpholino-benzyl)semicarbazide and its Transition metal(II) Complexes

N. Raman

The antibacterial activity of the monobasic bidentate Mannich base ligand, formed by the condensation of semicarbazide hydrochloride, morpholine and benzaldehyde, and its Cu(II), Co(II), Ni(II) and Zn(II) complexes against the bacteria Klebsiela pneumoniae, Salmonella typhi, Pseudomonous aeruginosa, Shigella flexneri, Staphylococcus aureus and Eicherichia coli has been carried out using nutrient agar as medium. The zones of inhibition of the synthesized compounds are compared with the free ligand and the standard ampicillin. All the complexes have higher activities than the free ligand and the standard.

Fixed Bed Column Study for the Removal of Ni(ii) from Aquatic Waste by NCRH

Upendra Kumar and Manas Bandyopadhyay

The fixed bed of sodium carbonate treated rice husk (NCRH) was used for the removal of Ni(II) from aquatic waste. The NCRH was found to be a efficient media for the removal of Ni(II) from wastewater. The column having a diameter of 2 cm, with different bed depths such as 10, 20 and 30 cm could treat 0.66 l, 1.32 l and 2.05 l of Ni(II) bearing wastewater with Ni(II) concentration 10 mg/l and flow rate 9.5 ml/min. Different column design parameters like depth of exchange zone, adsorption rate, adsorption capacity etc. were calculated. Effect of flow rate and initial concentration was studied. Theoretical breakthrough curve was drawn from the batch isotherm data and it was compared with experimental breakthrough curve. 0.01 M HCl solution was used for desorption of adsorption column

Synthesis and Characterization of Biologically Active Metal Complexes of Nimesulide

Divakara T. R., Nagaraja Naik, Arun V. S. and Pragasam A

Complexes of nimesulide with cobalt(II) nickel(II) and manganous(II) have been synthesised. These complexes have been characterised using elemental analysis, IR, TGA, 1H NMR, magnetic susceptibility and molar conductivity measurements. These studies revealed that they are having octahedral geometry of the type [ML(H2O)2X2] where M=Co(II), Ni(II) and Mn(II); L=C13H12N2SO5; X= Cl, Br, ClO4 and 1/2SO4. These nimesulide metal complexes are biologically active. The invitro antifungal studies indicated that these complexes are potent against a few tested fungi.

Use of Dyes in Photo Galvanic Cells for Solar Energy Conversion and Storage : Methyl Orange and Ascorbic Acid System

R. C. Meena and Gautam Singh

Photogalvanic effect was studied in photogalvanic cell containing Ascorbic Acid as reductant and Methyl Orange as photosensitizer. The photopotential and photocurrent generated were 740.00 mV and 140.00 mA, respectively. The observed conversion efficiency was 0.6961% and the maximum power of cell was 76.04mW. The storage capacity of the cell was 45 minutes in dark. The effects of different parameters on electrical output of the cell were observed and a mechanism has been proposed for the generation of photocurrent in photogalvanic cell.

Constraining Approaches in Seismic Tomography

Louis F. I., Vafidis A. P. and Louis I. F.

Two ways of dealing with the problems of stability and uniqueness in travel time inversion are proposed. They involve constraining conditions in the form of damping and smoothing of the solution. A direct evaluation of these two proposed schemes is presented which is useful in the selection of optimum values. A synthetic cross-hole data set with intermediate noise level was used in this study. Data and model RMS misfits were plotted against damping/smoothing parameters. These diagrams indicate that the damped least squares method gives acceptable results for damping values which correspond to the region of local minimum for both types of error. First and second difference regularization methods performed in general better since noise was generally suppressed and better tomograms were obtained for distinctive values of the free parameter, although harsh smoothing recovered no observable velocity features.

Review Paper : Envirocats - Ecofriendly Catalysts

S. S. Mahajan and S. S. Ghatpande

The conventional catalysts used in many organic reactions are often corrosive acids with a high toxicity level. They are hazardous to handle, produce a large volume of aqueous quench and are difficult to dispose off. The use of environmentally friendly supported reagent catalysts is a good alternative to the problems associated with traditional processes. The catalysts of Envirocat range, the classic example of supported reagent catalysts, are now available and offer a number of advantages over the conventional catalysts. The varied applications of Envirocat catalysts along with their advantages are reviewed in this article. Envirocat EPZG, EPIC and EPZ10 are discussed in more details.