Chromium toxic effect monitoring using ozonation method

Experimental validation off-line a nonlinear controller for removal of chromium using non-living cells of Yarrowia lipolytica

The removal of hexavalent chromium [Cr (VI)] using non-living cells of Yarrowia lipolytica was investigated. Batch and continuous studies on removal of Cr (VI) achieved 97% and 99% removal from aqueous phase, respectively. The specific uptake values at pH of 2 in batch process were 40.73 ± 1.3 mg/g and 30.09 ± 0.23 mg/g on non-living cells, when 100 and 200 mg/L of metal Cr (VI) concentrations were used. In order to investigate the regulation of Cr (VI) under continuous operation based on reaction volume numerically a new class of feedback controller from structure polynomial was designed. The proposed methodology was used to an experimentally kinetic model for a removal Cr (VI) from Yarrowia lipolytica biomass was showed satisfactory closed-loop performance the proposed controller. Starting from an off-line optimization performed in simulation, we present the controller implementation, focussing on the methodology required to could be suitable for implementation in real time. In our experimental results, we highlight some discrepancies between simulation and reality despite these differences, the controller managed to perform convergence to removal Cr (VI). Finally, the results validated with off-line samples suggest that the proposed control could be suitable for in application in potential scenarios for wastewater treatment.

Adverse hematological effects of hexavalent chromium: an overview

Workers of tanneries, welding industries, factories manufacturing chromate containing paints are exposed to hexavalent chromium that increases the risk of developing serious adverse health effects. This review elucidates the mode of action of hexavalent chromium on blood and its adverse effects. Both leukocyte and erythrocyte counts of blood sharply decreased in Swiss mice after two weeks of intraperitoneal treatment with Cr (VI), with the erythrocytes transforming into echinocytes. The hexavalent chromium in the blood is readily reduced to trivalent form and the reductive capacity of erythrocytes is much greater than that of plasma. Excess Cr (VI), not reduced in plasma, may enter erythrocytes and lymphocytes and in rodents it induces microcytic anemia. The toxic effects of chromium (VI) include mitochondrial injury and DNA damage of blood cells that leads to carcinogenicity. Excess Cr (VI) increases cytosolic Ca²⁺ activity and ATP depletion thereby inducing eryptosis. Se, vitamin C, and quercetin are assumed to have some protective effect against hexavalent chromium induced hematological disorders.