Green synthesis of selenium nanoparticles from sodium selenite using garlic extract and its enrichment on Artemia nauplii to feed the freshwater prawn Macrobrachium rosenbergii post-larvae

Thangavelu Satgurunathan, Periyakali Saravana Bhavan* and Subramaniyam Komathi

In this study, selenium nanoparticles (SeNPs) were synthesized from sodium selenite using garlic (Allium sativum) clove extract and characterized by UV, SEM, EDX, XRD and FT-IR, which revealed uniform, mono-dispersive and highly stable particles with the size range of 48-87 nm. 24 h LC50 of SeNPs 101.04 µg/L was used to enrich the Artemia nauplii at different durations (½ h, 1 h and 2 h) and fed to Macrobrachium rosenbegii post-larvae (PL) for 30 days as live feed which revealed that the ½ h enriched Artemia nauplii has promoted survival rate, growth rate, nutritional indices and concentrations of tissue biochemical constituents of M. rosenbergii PL significantly (P<0.05) followed by 1 h enrichment.

Furthermore, 101.04 µg/L of SeNPs were found to be non-toxic to M. rosenbergii PL when fed with up to 1 h enriched Artemia nauplii as the insignificant (P>0.05) alterations in activities of SOD and CAT were recorded. These facts suggest that 101.04 µg/L of SeNPs was the optimized concentration to enriched Artemia nauplii for ½ h - 1 h duration. Therefore, SeNPs can be used as sustainable material for nursery maintenance of M. rosenbergii PL.

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Synthesis and evaluation of 2-[2-cyano-3-(substituted phenyl)acrylamido]-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxamides for antioxidant and anti-inflammatory activities

Madhavi K.* and Visalakshi M.

A series of 2-[2-cyano-3-(substituted phenyl) acrylamido]-4,5,6,7-tetrahydrobenzo[b] thiophene-3-carboxamides was synthesized by Knoevenagel condensation of 2-(2-cyanoacetamido)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxamide with various substituted benzaldehydes in presence of toluene containing catalytic amounts of piperidine and acetic acid. The reaction was completed within 5-6 hours which gave the title compounds almost in pure form. All the compounds were characterized by their physical and spectral data.

The compounds synthesized were screened for in vitro antioxidant activity by scavenging 1,1-diphenyl-2-pricrylhydrazyl (DPPH), nitric oxide free radicals and by iron induced lipid peroxidation using rat brain homogenate. The active compounds were evaluated for anti-inflammatory activity by carrageenan induced rat paw edema assay. The present work revealed that the compounds of 2-[2-cyano-3-(substituted phenyl) acrylamido]-4,5,6,7-tetrahydrobenzo[b] thiophene-3-carboxamide containing phenolic substitution have greater antioxidant and anti-inflammatory activities.

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Chitosan from shrimp (Peneaus monodon) skin waste as natural coagulant to remove heavy metal Hg

Lukum Astin* and Rauf Asda

This study aimed to isolate chitosan from waste of shrimp skin and applied as environmentally friendly natural coagulant. This study included the isolation, characterization and application of chitosan in the adsorption of heavy metal Hg. Chitosan was obtained from waste of shrimp (Peneaus monodon) skin via deproteination, demineralization, depigmentation and deacetylation.

Optimization of adsorbent mass was carried out by varying the adsorbent mass of 0, 0.3, 0.6, 0.9, 1.2 and 1.5 g. In addition, the effect of pH was conducted by performing the adsorption under different pH of 2, 6, 7, 8 and 9. The results showed that the use of 1.2 g of chitosan gave Hg(II) removal of 99.86% or 9.986 µg/L. It could be concluded that chitosan as natural coagulant could adsorb Hg(II) in water.

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Soil Respiration in Rubber Tree Plantation applied with Biochar

Hanpattanakit Phongthep*, Wattanahemmakorn Jiranut, Sudjarit Tanakit, Jaiarree Sathaporn and Taweekij Sukanya

Soil respiration (Rs) is a key component of the terrestrial ecosystem carbon cycle. It is linked directly with the dynamic of soil carbon and its possible feedbacks to global warming. In Thailand, rubbeer tree plantation (Hevea brasiliensis Muell. Arg.) has increased substantially especially in the eastern and northeastern parts in Thailand. On the other hand, application of biochar to soil has been suggested as a potential way of enhancing soil carbon sequetration and plant productivity. However, we know little about its effects on soil carbon dynamics, espeically soil respiration. In this study, the effect of biochar on soil respiration in rubber tree plantation was assessed.

Rs between wet season [April to October] and dry season [November to March] was significantly different (p-value ≤ 0.05). The results show that soil moisture is a main driver of soil respiration at seasonal scales. The correlation between soil respiration and soil temperature was negative when temperature increases but positive when soil moisture increases (p-value ≤ 0.05). The results also show that biomass of rubber tree did not differ significantly among treatments (T3=2,212 > T2=2,187 > T4=2,072 > T1=2,027 kg dry matter ha-1). Thus, plant growth and soil respiration did not stimulate by biochar application but benefits through soil carbon sequestration can be recognized.

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Potentiometric Determination of Lead (II) ion by using 2-[(4-Chloro-Phenylimino)-Methyl]-Phenol as an Electroactive Material

Dogra P., Sharma H., Sharma J.* and Sharma N.

Potentiometric lead sensor was prepared by using 2-[(4-chloro-phenylimino)-methyl]-phenol as as an ionophore and epoxy resin as a binding material. A membrane with 60% Schiff base exhibited the best performance in the concentration range 1.0X 10−6 to 1.0X 10−1 mol/dm3 with Super Nernstian slope of 43±0.1 mV/decade. The electrode shows a fast response time (< 10 sec) and could be used for a period of 4 months with a good reproducibility. The proposed electrode reveals very high selectivity for Pb+2 in the presence of transition metal ions such as Mg+2, Mn+2, Co+2, Cu+2, Ni+2, Cr+2 and Cd+2 etc. at concentrations 1.0×10−3 M and 1.0×10−4 M. Effect of internal solution concentration was also studied.

The proposed sensor can be used in the pH range of 2.50 - 9.0. The practical utility of the sensors has been shown by using it as an indicator electrode in the potentiometric titration with EDTA. Electrode was employed for direct determination of lead in rocks with a good agreement with the results obtained by Atomic Absorption Spectroscopy.

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Processing of nano TiO2 and its use as adsorbent in water purification

Ravindhranath K.* and Ramamoorty Mylavarapu

The green synthesis of nano particles based on adopting the extracts of plant materials is globally investigated. The nano particles produced by these phyto-based methods, are endowed with bio-compactability, eco-friendly nature and improved sorption nature. In this review, investigations pertaining to the synthesis of nano TiO2 particles by conventional as well as plant-mediated methods and their use as adsorbent in the removal of potential pollutants from waste water are emphatically discussed.

Further, the potential areas of research, challenges involved in them, the need of immobilizing the nano particles by trapping them in the matrix of films or beads so as to counter the pressure head loss by virtue of size when the particles are in compact bed, are discussed.

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Recent development of graphene synthesis by physico-chemical and electrochemical methods

Ravindra Bharat Kohakade, Senthilkumar Elumalai, Raghu Subash Chandrabose and Raman Kalaivani*

Graphene is a remarkable material which has high mechanical strength with high electron mobility, high surface area and is highly transparent. Synthesis of graphene with high quality and quantity via economic ways is highly desirable and meaningful for practical applications. Electrochemical Exfoliation is green and cost-effective method. Synthesis of graphene by chemical method is also carried out. This review gives brief explanation on synthesis of graphene by electrochemical exfoliation and physico-chemical methods.

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