Chromium is one of the 25 most widespread elements in the Earth’s crust and occurs as an indelible non-volatile trace element in raw materials used in cement clinker production (clay, limestone and iron additives in particular). Chromium in raw materials mentioned above is mainly in form of trivalent chromium. Naturally occurring chromium (III) is not initially harmful, since it is chemically s...

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 in...

The adsorption of hexavalent chromium on Kaolinite and Illite was studied in order to evaluate their potential for the reduction of hexavalent chromium mobility and their possible application for the treatment of polluted sediment. The influence of various parameters affecting the adsorption of hexavalent chromium, such as the pH of aqueous solution, the ionic strength and the initial metal ion...

The essentiality and carcinogenicity of chromium depend on its chemical form. Oxidation state and solubility are particularly important in determining the biological effects of chromium compounds. For this reason, total chromium measurements are of little value in assessing its nutritional benefits or its toxicological hazards. Aqueous sodium carbonate-sodium hydroxide solutions have been succe...

Chromium exists primarily in two forms: trivalent and hexavalent. Trivalent chromium is present in the cationic form as Cr+3 and is an essential nutrient, but hexavalent chromium is toxic and exists as an anion, either as chromate (CrO4 -2) or dichromate (Cr2O7 -2). Therefore, the analysis of total chromium does not always provide a true indication of the effects of chromium present in a sample...

Purpose: This study aimed to analyze the effects of removal of hexavalent Chromium using carbonated almond green hulls. In the present study, derived carbon fromalmond green hulls of zonal district of Iran were used to remove hexavalent Chromium from Synthetic wastewater. Materials and Methods: The effects of pH (2-10), Adsorbent dose (2-24 g/L), Cr (VI) concentration (10-100 mg/L), Contact tim...

aims: heavy metals are the main pollutants in nature. chromium is a heavy metal which is widely used. hexavalent chromium solubility and mobility in aqueous solutions is so high and it is easily reduced. biosorption is a process in which heavy metals are uptake through passive binding by nonliving biomass from aqueous solutions. the present study aimed to determine the capability of powdered sp...

In this work, a low-cost lignocellulosic adsorbent with high biosorption capacity is proposed, suitable for the efficient removal of hexavalent chromium from water and wastewater media. The adsorbent was produced by autohydrolyzing Scots Pine (Pinus Sylvestris) sawdust. The effect of the autohydrolysis conditions, i.e., pretreatment time and temperature, on hexavalent chromium biosorption was i...

Concentration levels of hexavalent chromium in contaminated soil and in Zea mays plant parts were determined and Cr(VI) bioaccumulation and bioconcentration capacity of this plant were discussed. Zea mays seeds were sown in 40 mg Cr(VI)/kg dw polluted soil. After harvesting it was observed that hexavalent chromium concentrations in plant organs decreased in the following order: roots > stems > ...

Chromic oxide is an important basic chemical and finds many applications including metallurgical materials, green pigments, construction materials, refractory materials and catalysts. Presently, the industrial production of chromic oxide generally employs two processes (Ding, 2003): one is the reduction of sodium dichromate with ammonia sulfate; the other is the thermal decomposition of chromic...