Research Journal of Chemistry and Environment

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Research Journal of Chemistry and Environment

Estimating Evapotranspiration and understanding its variations in a Seasonal Dry Dipterocarp Forest, Western Thailand

Sanwangsri Montri, Hanpattanakit Phongthep and Chidthaisong Amnat*

We analyzed 3-year eddy-covariance data (2009-2011) to investigate the evapotranspiration (ET) in a dry dipterocarp forest in western Thailand. The objectives of our study were: (1) to quantify ET in this seasonal forest and 2) to understand the diurnal and seasonally patterns of ET and its drivers. The diurnal patterns of ET was characterized by a rapid increase during early morning, reached the highest at noon and decreased until sunset. Variations during the night time were small. On the seasonal scale, ET was positively correlated with seasonal rainfall and soil water content and negatively correlated with vapor pressure deficit.

The annual average of ET was 2.55±1.20 mm day-1. The average ET in wet season (3.61 ±0.39 mm day-1) was higher than during the dry season (1.15±1.17 mm day-1). The annual, wet and dry season totals of ET averaged during these three years were 935±117, 222±87 and 628±34 mm respectively. The annual ET accounted for about 95% of total annual rainfall.

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Genetic diversity assessment in chronosequence iron mine overburden spoil using RAPD markers

Pasayat Mamata and Patel Amiya Kumar*

Genetic diversity among microbial populations in seven different age series iron mine overburden spoil and nearby NF soil was evaluated through the culture-independent approach using RAPD markers, a PCR-based DNA fingerprinting technique. Twenty primers were used for amplification of metagenomic DNA and the banding patterns of 24 metagenomes were compared to assess the microbial community structure among eight different soil profiles. The Nei’s genetic diversity and Shannon’s information index were estimated to be 0.4046 and 0.5857 respectively. Besides, the population diversity and estimated gene flow were found to be 0.1415 and 0.2689 respectively.

Dendrogram analysis based on neighbour joining method and bootstrapping revealed that the 24 microbial metagenomes were well segregated into four independent clusters. Analysis of molecular variance (AMOVA) indicated that 52% genetic variability among population was attributed to different soil profiles where as 48% variability was accounted within the population attributed to different habitats. The study correlated well with temporal and spatial variations among different age series iron mine overburden spoil and nearby NF soil indicating the PCR-based DNA fingerprinting using RAPD markers as useful tool for discriminating microbial communities and relatedness. Further, the analysis revealed gradual microbial amelioration with existing genetic composition facilitating mine spoil reclamation over time supporting greater microbial diversity.

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Synthesis and antimicrobial evaluation of novel sulphur bridged 2-oxo -1,2,3,4-tetrahydropyrimidine derivatives

Saravanan Dhandayutham*, Rajamanickam Kannadhasan and Sankaranarayanan Murugesan

In this study, novel series of eleven 2-oxo-6-(4-pyridin-4-yl-thiazol-2-yl sulfanylmethyl) -1,2,3,4-tetrahydropyrimidine derivatives (3a-k) was synthesized by reacting 4-(pyridin-4-yl)-1, 3-thiazol-2-thiol (1) and ethyl-4-chloroacetocetate in dimethylformamide. To this reaction mixture, anhydrous potassium carbonate was added and the reaction mixture stirred at room temperature afforded ethyl 3-oxo-4-[(4-pyridin-4-yl-1,3-thiazol-2-yl)thio]butanoate (2) as intermediate. This on subsequent treatment with urea and substituted aryl aldehyde afforded the titled compounds (3a-k).

The structural features of the synthesized compounds were characterized by elemental, IR, 1H NMR, 13C NMR and Mass spectral analysis. All the compounds were evaluated for their antimicrobial activity against four bacterial strains (E. coli, S. aureus, K. pneumonia and B. subtilis) and two fungal strains (C. albicans and A. niger). Docking studies were also performed against glucosamine-6-phosphate synthase enzyme in order to study the putative binding mode of the active compounds.

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Doping of Eu3+ into nanoscale zinc stannate ceramic and screening for solar degradation of organic dye, p-chlorophenol – a green approach

Sudha Parimala S.* and Prashanna Suvaitha S.

Nano crystallite zinc stannate ceramic was prepared by sol-gel process using plant extract as the medium. The as-synthesised zinc stannate was further doped with Eu3+ions in the weight percentage ratio of 0.25%, 0.50% and 0. 75% by solid state reaction at a lower calcination temperature. The presence of orthorhombic perovskite phase of zinc stannate with an average crystallite size of 35 nm was identified by the PXRD study. SEM images indicated the presence of spherical nano crystallites with higher agglomeration upon doping while EDX spectrum was suggestive of selective doping sites available in stannate matrix with the percentage of 0.75% by weight.

The stannate ceramic was efficient in solar degradation of the textile dye, methylene blue (upto 68%) and the major organic pollutant p- chlorophenol (upto 48%). There was also a good result about anti-bacterial activity. Ultimately the study provided an efficient and cost- effective method for the synthesis of Eu3+ doped zinc stannate ceramic with wider applications.

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A simple and rapid method for determination of Se (IV) using methylene blue dye

Kulkarni Preeti* and Arote Ganesh

A rapid, simple and sensitive spectrophotometric method is described for determination of trace amounts of selenium (IV) in aqueous samples using methylene blue dye (MB) as a chromogenic reagent. Methylene blue is a redox indicator and shows a colour change on reaction with iodine. The proposed method is based on the iodometric reaction of selenium (IV) with excess of potassium iodide in acidic medium to liberate iodine. The liberated iodine reduces methylene blue dye. The reaction can be monitored spectrophotometrically by measuring decrease in absorbance of methylene blue dye at 660 nm.

The optimum reaction conditions such as effect of dye concentration, effect of KI, effect of acid concentration and other analytical parameters for the iodometric reaction were evaluated. The optimized reaction conditions were used for selenium determination in the range of 0.2 μg mL-1- 3 μg mL-1 in aqueous samples. The proposed method is successfully applied to determination of selenium (IV) in pharmaceutical and antidandruff shampoo samples.

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Reuse of treated domestic wastewater using Moringa oleifera

Shukla Neha and Paul Kakoli Karar*

All over the world, disposal of treated domestic wastewater effluent, shortage of freshwater and increased cost of wastewater treatment are the major problems. Treated domestic wastewater can be considered as new water resource in demanding sector like agriculture. Wastewater contains heavy metals and other chemical species which may be helpful for the agricultural purpose as fertilizer constituents. To maintain all nutrients within specified range, powder form of dried seed of Moringa oleifera (MO) is added into treated domestic wastewater. After the addition of MO seed powder, it was found that MO has great potential to fulfill the nutritional demand of treated domestic wastewater.

In present work, optimization, mathematical modeling using DOE and dissolution kinetics were also performed to study the optimized condition of dissolution process of MO seed powder in treated domestic wastewater. The study found that dissolution kinetics follows the diffusion controlled shrinking core model (R2 =0.977) having 91.63 kJ/ mol of activation energy. It is observed that addition of MO has great impending to fulfill the chemical requirement of treated domestic wastewater for agricultural purpose. This technique may help to minimize fresh water demand, provides economical wastewater treatment technology and aid in safe reuse of treated domestic wastewater.

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