Egg consumption is very high throughout the world and with it comes enormous amount of waste eggshells. To reduce and utilize these wastes, eggshell wastes were simply transformed to low- or high-purity calcium carbonate grades by washing, crushing, and drying to use as raw materials for producing highly valuable calcium phosphate products. Low-purity calcium carbonate grade was used to prepare triple superphosphate for using in fertilizer industry, whereas high-purity calcium carbonate grade was used to produce dicalcium phosphate dihydrate, monocalcium phosphate monohydrate, and tricalcium phosphate for using in mineral feed and food additive industries. All calcium phosphate samples obtained by simple, rapid, cheap, and environmentally safe method using eggshells and phosphoric acid were identified and their structural phases and impurities were determined by XRF, XRD and FTIR techniques. Thermal behaviors of raw materials and the prepared calcium phosphates excepted tricalcium phosphate were investigated by TG/DTG techniques. The methodologies described here will be useful to manage eggshells by converting them to highly valuable products, which can solve eggshell wastes problem from industries and communities. This finding supports the viewpoint of zero waste operation to produce value-added products for obtaining sustainable development, which may be selected as an alternative way for material recycling and waste management in the future.

This study was designed to manage golden apple snail shells, the wastes created in large amount daily from the consumption of the meat of golden apple snail (Pomacea canaliculata) shells by transforming them to advanced compounds; calcium carbonate (CaCO3), monocalcium phosphate monohydrate [Ca(H2PO4)2·H2O], and tricalcium phosphate [Ca3(PO4)2]. They were successfully prepared by a rapid, simple, environmentally benign method using easily available and low-cost instrument. All synthesized samples were characterized by X-ray fluorescence, X-ray powder diffraction, FTIR spectroscopy and scanning electron microscopy to confirm the identities with the standard materials. The reproducibility and low-cost method suggest that it could be used in industry for a large-scale production of calcium carbonate, monocalcium phosphate monohydrate and tricalcium phosphate from golden apple snail shells as a replacement of natural mineral resources and be a good way to manage these shell wastes.

Au nanoparticles supported on alumina (Au/Al 2 O 3 ) with average particle size of 3.9 ± 0.7 nm and surface plasmon band centerned at 516.5 nm were prepared by deposition–precipitation method, and their photocatalytic activities for the reduction of nitrobenzene using either formic acid in acetonitrile (method A) or KOH in 2-propanol (method B) were investigated. Even at room temperature, the Au/Al 2 O 3 was found to be highly active and selective for conversion of nitrobenzene to aniline when used with formic acid in acetonitrile or to azobenzene when performed with KOH in 2-propanol under irradiation with green light-emitting diode (517 nm).

Abstract:The chirality-directed self-assembly of bifunctional subunits around a structural metal-typically, zinc(I1)-is used to form a heteroleptic complex in which a second set of ligating groups are suitably disposed to bind a second metal, forming a heterobimetallic catalyst system. We find that subtle changes in the structural backbone (i.e., ligand scaffold) of such chiral bidentate self-assembled ligands (SALs) can be used to manipulate the ligand topography and chiral environment around catalytic metal; thus, the scaffold can be optimized to maximize asymmetric induction. Using this combinatorial strategy for ligand synthesis, a preliminary study was carried out in which a library of 110 SALs was evaluated in the rhodium-catalyzed asymmetric hydrogenation of a simple N-acyl enarnide. The level of enantioselectivity obtained varies from near racemic to greater than 80 % ee as a function of the ligand scaffold, with the possibility of further improvement yet to be explored.