Research Journal of Chemistry and Environment

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Highly Crystalline and Transparent Polylactide toughened with Oligomeric Polyesters

Zhao Yang, Jiang Degong, Chen Shou, Xiao Min, Wang Shuanjin*, Peng Xiaohua and Meng Yuezhong*

To overcome the disadvantage of the brittle nature of polylactide (PLA), three different oligomeric polyesters (OPE) were synthesized and used as toughness toughing agents for PLA. The mechanical properties, morphology, thermal properties and crystalline characteristics of the toughened PLA were fully investigated. The tensile and notched Izod impact test results show that the synthesized three oligomeric polyesters are miscible with PLA and can then toughen PLA effectively. The toughing efficiency order follows OPE-A > OPE-M > OPE-P.

The experimental results also indicate that the introduction of OPE can decrease the melting point and can increase the crystallinity of PLA. Compared with neat PLA, much more crystal nucleus was observed using polarized optical microscopy (POM), demonstrating that OPE-A can accelerate the growth speed of PLA spherulite. Finally, a transparent and toughened PLA with very low migration rate of toughing agent from inner PLA towards its surface was successfully obtained.

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Study of nano scale biphasic Hydroxyapatite at lower processing temperature - Influence of Anadara granosa seashell as a precursor

Sudhaparimala S.

Hydroxyapatite is a widely studied bio ceramic as a bone substitute and a dental filler. There is need to improve its inherent property by the methods of preparation, use of precursors and reaction parameters. The present study aimed at identification of sea shells of anadara granosa in the coastal India and their effective conversion to the nano scale Hydroxyapatite(HAp) by a simple wet chemical precipitation and a low calcinations temperature. The structural, morphological and biological aspects of the sample were evaluated with respect to the HAp sample prepared from the synthetic calcium carbonate.

The results of the study were unique. A biphasic hydroxyapatite along with β tri calcium phosphate with the crystallite size of 25nm was achieved. The formation of near spherical and semi crystalline hydroxyapatites along with biologically important minerals of Zn, Mg, Sr, Mn was responsible for the enhanced toxicity towards common dental fungus, candida albicans and bacteria streptococcus mutans cells considered for the study. Hence, from the biological point of view, it can play a better role as dental filler and bone replacement. The study provided an energy efficient, cost effective simple methodology of recycling the sea shells into the most important bio ceramic of hydroxyapatite.

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Effect of Silicon and Phosphorus on available Si, P, Fe and Mn Content and Nutrient Ratio of P-Stressed Maize (Zea Mays L.)

Meena O.P., Patel K.C. and Malav J.K.*

A pot trial was conducted at Anand Agricultural University, Anand, Gujarat (India), during 2011-12. The effort was made to study the influence of Si and P supply on available Si, P, Fe and Mn content and nutrient ratio of P-stressed maize. Treatments were arranged in a factorial completely randomized design with Si factor at five levels (0, 100, 200, 300 and 400 ppm). Two levels of P (0 and 40 mg P kg soil-1) and maize were taken as a test crop with three replicates. The results indicated that application of phosphorus (P40) significantly decreased the Si: P ratio in P-deficient soils and highest P: Fe ratio was observed at 11.64 and 10.82 due to P40 level in both the soils. The highest P: Mn ratio (138.36 and 152.00) was recorded under Si300xP40 in both the soils.

The application of phosphorus (P40) also significantly increased the P: Zn ratio in both P-deficient soils. The increase in P: Zn ratio could be due to decrease in Zn uptake on account of increased P uptake. Overall results indicated that application of silicon @ 300 ppm and phosphorus at 40 ppm gave a maximum maize yield under P stress condition and also improved Si, P, Fe and Mn utilization by maize plants.

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Kinetic study of thermal degradation of microalgae Arthrospira platensis by iso-conversational methods

Gouda Narayan, Panda Achyut K.* and Meher S.N.

The thermal degradation kinetics of microalgae Arthrospira platensis was investigated by dynamic thermogravimetry in a nitrogen atmosphere, at the temperature range of 30 °C to 900 °C at constant heating rates of 10, 20, 40, 60, 80 and 100 °C/min respectively. Three distinct mass change stages in the thermogravimetric analysis curves indicated that the degradation was attributed to different components.

The model-free iso-conversional methods including Friedman, modified Coats and Redfern, Kissinger and Flynn–Wall–Ozawa methods have been employed to calculate activation energies as a function of the extent of degradation. The average activation energies calculated using the methods are found similar. The results show that these methods were suitable and effective to describe the thermal degradation of the microalgae.

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pH- metric studies on stability constants of the complexes of Myristic acid with transition metal ions in Binary Solvent Mixture

Vijayarohini P.*, Caroline Mercy Andrew Swamidoss and Bangaru Sudarsan Alwar S.

The interaction between myristic acid and metal ions Mn(II), Cu(II) and Zn (II) in 70% (v/v) DMF- 30% (v/v) water mixture and 50% (v/v) DMF- 50% (v/v) water mixture was studied pH-metrically at an ionic strength of 0.1M at 303 K. It has been observed that the metal ions form 1:1 and 1:2 complexes with myristic acid. The data obtained was used to compare the values of proton-ligand stability constant and metal-ligand stability constants.

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Screening of phenolic compounds from Abelmoschus esculentus L extract fruits and in vitro evaluation of antioxidant and antibacterial activities

Zouari Ahmed Rachida, Ouahrani M. Ridha, Laouini S. Eddine* and Meneceur Souhaila

Ethanolic fruit extracts collected in August, September and October from Abelmoschus esculentus L were analyzed for their phytochemical profile, the antioxidant capacity to scavenge free radical and antibacterial capacity. The total phenolic content was evaluated in three fruit extracts using Folin–Ciocalteu reagent. Several biochemical assays were used to evaluate their antioxidant properties: 2,2-diphenyl-1-picryl-hydrazyl (DPPH˙), ferric reducing antioxidant power (FRAP) and total antioxidant activities assays. Further, antibacterial activity was screened using disk diffusion method against Escherichia coli, Staphylococcus and Pseudomonas aerigunosa. Three fruits extracts of Abelmoschus esculentus L were found to contain a high total phenolic content (190.11± 5.75 for AFE, 159.64± 4.28 for 138.19± 4.34 mg GAE/g DW for OFE).

The fruit extract exhibited potent antioxidant activity determined by DPPH˙, FRAP and total antioxidant activity assays, the high antioxidant capacity of all extracts has been observed and related to the relative amounts of total phenolic content with good antioxidant properties (DPPH˙ assay, IC50= 14.33±0.55 mg/ml for AFE> IC50= 15.33±0.58 mg/ml for SFE> IC50= 17.43±0.63 mg/ml OFE). All bacteria showed high sensitivity against fruits extract and the AFE had the best antibacterial activity against Staphylococcus aureus. The results suggest that the fruits of Abelmoschus esculentus L can be considered as a good source of natural antioxidant and antibacterial drugs.

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Pre-concentration and quantitative determination of Fenofibrate present in water

Koppula Santhosh Kumar and Samnani Prakash*

Fenofibrate, fibric acid derivative, is used for regulating plasma lipids and treatment of hyperlipoproteinaemias. Its presence in aquatic environment has been reported recently. Understanding the fate of this drug in water systems could lead to better waste water treatment options that would lead to more complete removal of such compounds. To aid in this understanding, a simple, accurate and sensitive pre-concentration method for determination of fenofibrate in water has been developed based on solid phase extraction and HPLC.

Macroporous beads of polystyrene divinyl benzene (PSDVB) polymer were used for pre-concentration followed by chromatographic determination. Experimental parameters were optimized. This optimized method can detect fenofibrate concentration upto 0.046 mgL-1 after pre-concentration. This method was used for determination of fenofibrate in treated sewage water collected from a municipal sewage treatment facility.

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Assessment of Surface Water Quality of the Turag River in Bangladesh

Begum Tahmina, Dey Sujan*, Roy Karabi, Mostofa Kamal Abu Hena, Khan Ruhul Amin and Sultana Sharmin

Turag River has significant importance for the economic development of Bangladesh and the inhabitants depending on this river for various purposes like fishing, irrigation, drinking and other household activities. But the river is getting polluted due to excessive industrial and anthropogenic activities. To determine the water quality of Turag River by assessing different physicochemical and microbiological parameters, water samples were collected from four stations of the river in two different seasonal periods and analyzed according to the standard procedures.

The obtained values of Temperature, pH, Salinity, TDS, TA, EC, TH, Chloride content, Free CO2, DO, Nitrate and Sulfate were compared with the recommended values of Bangladesh and WHO standard for river water quality. Most of the physicochemical parameters exceeded the Standard value. Total Viable Count, Total Coliform and Fecal Coliform Count were also found to be higher than the standard value of WHO indicating fecal contamination of the river water.

Water quality index (WQI) was calculated to determine the level of pollution in two different seasons. It was observed that water quality of the river reached to critical point of pollution in both the seasons. Therefore, it is high time to take initiatives to save the river from further pollution.

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