Non-enzymatic Amperometric sensor for the detection of Hydrazine as an Environment Pollutant

Kumar Harish* and Neetu

Carbon allotropes like graphene and carbon nanotubes, have been incorporated in amperometric sensors for sensitive and selective detection of environment pollutants. An electrochemical biosensor based on graphene powder working electrode whose properties are modified with conducting polymer polyaniline (PANI) was specially designed and fabricated for electrochemical detection of environment pollutant like hydrazine.

Electrochemical characterization was carried out by using cyclic voltammetry, ampereometry, linear sweep voltammetry and optical microscopy. The developed amperometric sensor displays good electrochemical-activity towards the detection of hydrazine. Storage and stability conditions of the working electrode were also tested. Fabricated non-enzymatic amperometric sensor was successfully used for the precise, sensitive and specific detection of hydrazine present as an environment pollutant.

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Evaluating the short-term effects of rice-maize crop rotation on soil organic carbon changes

Ponphang-nga Pancheewan and Chidthaisong Amnat*

This study aimed to improve our understanding of soil carbon (C) change when cropping changed from maize to lowland or upland rice under field experiments. Measurements of stable carbon isotope of soil organic carbon (SOC) also investigate the incorporation of carbon derived from C4 plants (maize) or C3 plants (rice) into SOC. The amounts of biomass incorporation were significantly affected to SOC. Changing from maize to continue upland rice resulted in SOC loss of about 5% after the three crop cycles. In this study, after the second crops and when the cultivation system was changed from maize to lowland rice, the δ13C value of soil carbon was shifted from –18.77 ‰ to–20.73‰. This represented the rapid incorporation of rice-derived carbon into SOC.

Conversion of continuous maize to continuous upland and lowland rice resulted in a decrease in C concentrations in light fractions, especially in lowland rice rotation with maize. Since majority of SOC was in the heavy fraction (>80%), it might play the important role in storing carbon. Consequently, this study demonstrated that crop rotation could significantly affect soil carbon sequestration potential and such effects could be detected as early as when the first land conversion occurred.

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High resolution accurate mass multi-class multi-residue screening method for the analysis of honey samples collected from various parts of Kerala state, India using LC-QTOF

Prasanth J., Vincy M.V.* and Brillliant R.

A sensitive and specific liquid chromatography-electrospray ionization high resolution mass spectrometry (LC/ESI-HRMS) method was developed for the multi-class multi-residue screening of eight natural source honey samples collected from various locations of Kerala State, India. A generic sample extraction protocol based on liquid-liquid extraction (LLE) was employed. Minimal LC separation by a generic gradient program based on reverse phase chromatography was developed. Single injection workflow using TOF-MS survey scan followed by dependent TOF-MS/MS scans was used for the simultaneous screening, identification and confirmation of pesticide and antibiotic residues. High resolution TOF MS/MS data generated by Auto MS/MS workflow was also used for LC -MS/MS mass spectral library search.

Honey samples collected from natural sources were considered to be safe for consumption; however, screening of eight honey samples indicates presence of pesticides; pharmaceuticals, degradation products, mycotoxins and veterinary antibiotics. Presence of identified compounds in the sample is confirmed by matching the obtained fragmentation pattern with insilico fragments generated by the structure of compounds. Present study also confirms that same workflow can be used for identification and confirmation of totally unknown compounds present in the honey samples. Developed method is validated by running mixed aqueous standards of pesticides and antibiotics as well as matrix matched quality control samples.

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Removal of Cadmium (II) from aqueous systems by adsorption-flocculation using organo-bentonite clay

Ravikumar K.* and Udayakumar J.

The conventional water treatment methods are not suitable for removing hazardous pollutants from the aqueous systems. These methods are mainly removing the suspended matters present in water. But due to natural and anthropogenic activities, water is contaminated with heavy metals, fluorides, arsenic, pesticides etc. These materials are in dissolved form and the present system of water purification cannot remove these pollutants within specified limit. Some of these materials are carcinogenic, teratogenic, mutagenic and endocrine destructive chemicals. So, a water treatment technique which can remove both the suspended and dissolved matters that are hazardous to health is novel.

Cadmium is the most harmful heavy metal of the chemical pollutants and is of particular concern due to its toxicities to humans. In this study, composite coagulant prepared by using bentonite clay material as adsorbent and moringa seed cake coagulant as biopolymer were used for removing cadmium ions present in aqueous systems. 99% of cadmium ions were removed from water by coagulation–flocculation and double filtration.

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Improvement in thermal stability, thermomechanical and oxygen permeability of PA6 by ODA modified Ca3(PO4)2 nanofiller

Barman Ghanshyam1, Sonawane Shriram S.*, Wasewar Kailas L., Rathod Ajit P., Parate Vishal R., Sonawane Shirish H. and Shimpi Navin G.

PA6/ Ca3(PO4)2 nanocomposites were made by melt extrusion process using a counter rotating twin-screw extruder using PA6 polymer with Ca3(PO4)2 nanoparticles. Injection moulding is used to prepare a specimen. ODA (octa decyl amine) was used as a modifier to improve the compatibility and dispersion of nanoparticles in the matrix. The thermal, dynamic mechanical and gas permeability properties of namocomposites were analyzed to study the influence of filler loading.

The improvement in the crystallinity of PA6/ Ca3(PO4)2 composites was observed compared to that of the neat PA6. The improvement in surface compatibility led to enhancement in thermal, thermomechanical and gas barrier property. The thermal decomposition temperature, storage modulus, crystallinity. The storage modulus of nanocomposites is improved by 9%,15%,29%, 15%, 29% and 30% for loading of 1,3,5 and 7% Ca3(PO4)2 in comparison to neat PA6. The oxygen permeability is reduced by 100%.

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Exploring the potential of indigenous bacteria for reduction of hexavalent chromium

Panda Swati Sucharita, Basu Aradhana and Dhal Nabin Kumar*

Indigenous bacterial isolates from the chromites mining waste of Sukinda Valley, Odisha, India, showed a considerable reduction of hexavalent chromium Cr (VI) through adaptation and consortia development. The bacterial isolates showed a high tolerance at 500−1000 ppm of Cr (VI). The potent gram positive strain was identified as Bacillus cereus on the basis of 16S rDNA gene sequencing which reduced 97% of Cr (VI) at 370C and pH 9.0. The strain also exhibited resistance to various antibiotics such as erythromycin, chloramphenicol, ofloxacin etc.

Field Emission scanning electron microscopy revealed Cr (VI) precipitates on the cell surface and electron dispersion X-rays showed the presence of chromium after the reduction. Microbial reduction of toxic Cr (VI) may be very successful since biological strategies provide cost effective green technology and native bacterial strains have significant potential to be used as a tool for bioremediation of chromites mine sites.

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