Metal transport phases in rivers around Jameshedpur†

Transport phases of four metals of geochemical and water quality importance were investigated in rivers around Jamshedpur. The metals iron, manganese, zinc and copper were partitioned into dissolved, adsorbed and or ion exchangeable, solid organic, oxide coating and crystalline phases applying filtration for the dissolved phase and a chemical fractionation scheme for the particulates. Iron and copper were transported mainly in the particulate phases at all sites, while manganese and zinc were found in the dissolved phase up to a hundred percent depending on the pH of water sample and pollution at the site concerned. Except copper more than 75 percent of all other three metals occurred in transport modes thought to be available to aqueous and biotic interactions. Copper was in available phases from 50 to 70 percent. The significance of metal partitioning as a factor in controlling metal availability and toxicity to biota is discussed.     

Investigation of the Structure and Properties of Silk Fibers Produced by Actias lunas

This paper reports the structure and properties of silk fibers produced by Actias lunas in comparison to Bombyx mori and the common wild silks. Considerable efforts are being made to find new sources for natural silk and also to develop regenerated protein fibers to supplement the limited amounts of B. mori and wild silks available in the market. In addition, it has been found that non-traditional silks have unique properties and utilizing uncommon wild silks can provide income and employment to indigenous people where the wild silks are found. Actias lunas belongs to the Saturniidae family of silk producing insects. However, the structure and properties of silk produced by A. lunas have not been studied. This research showed that the silk fibers produced by the luna moth had morphological and physical structure similar to that of the common wild silks but tensile properties similar to that of B. mori silk. A. lunas silk fibers are composed of higher amounts of hydrophobic amino acids and had much less glycine than B. mori and common wild silks. With a fineness of 2 denier, breaking tenacity of 4.3?g/den and breaking elongation of 10.9?%, the tensile properties of A. lunas silk fibers were similar to that of B. mori and much better than that of the common wild silks that are coarser and have lower breaking tenacity. A. lunas fibers show good potential to be useful for applications currently using B. mori silk.     

Coal fly ash utilization: low temperature sintering of wall tiles

We present here a study of the sintering of fly ash and its mixture with low alkali pyrophyllite in the presence of sodium hexa meta phosphate (SHMP), a complex activator of sintering, for the purpose of wall tile manufacturing. The sintering of fly ash with SHMP in the temperature range 925-1050 degrees C produces tiles with low impact strength; however, the incremental addition of low alkali pyrophyllite improves impact strength. The impact strength of composites with 40% (w/w) pyrophyllite in the fly ash-pyrophyllite mix satisfies the acceptable limit (19.6J/m) set by the Indian Standards Institute for wall tiles. Increasing the pyrophyllite content results in an increase in the apparent density of tiles, while shrinkage and water absorption decrease. The strength of fly ash tiles is attributed to the formation of a silicophosphate phase; in pyrophyllite rich tiles, it is attributed to the formation of a tridymite-structured T-AlPO(4) phase. Scanning electron micrographs show that the reinforcing rod shaped T-AlPO(4) crystals become more prominent as the pyrophyllite content increases in the sintered tiles.     

Conducting polymers/zinc oxide-based photocatalysts for environmental remediation: a review

The accessibility to clean water is essential for humans, yet nearly 250 million people die yearly due to contamination by cholera, dysentery, arsenicosis, hepatitis A, polio, typhoid fever, schistosomiasis, malaria, and lead poisoning, according to the World Health Organization. Therefore, advanced materials and techniques are needed to remove contaminants. Here, we review nanohybrids combining conducting polymers and zinc oxide for the photocatalytic purification of waters, with focus on in situ polymerization, template synthesis, sol–gel method, and mixing of semiconductors. Advantages include less corrosion of zinc oxide, less charge recombination and more visible light absorption, up to 53%.