A trivalent chromium electroplating process has been io use commercially in North America since its introduction in 1975. Based upon years of laboratory and in-plant experience and testing, many process performance characteristics and physical properties of deposits have been determined. This paper compares the performance of trivalent chromium with hexavalent chromium processes. Factors such a...

Potato peels which are a low cost, renewable agroindustry by-product were used for the removal of hexavalent chromium from aqueous effluents. Batch experiments were carried out with an artificial effluent comprising of potassium dichromate in deionised water. The effects of the initial hexavalent chromium concentration, dose of biosorbent, and removal kinetics were explored. An adsorbent dosage...

In the different compartments of the environmental chromium occurs mainly in the oxidation states (III) and (VI). Although Cr(III) is an essential trace element for humans, Cr(VI) is highly cancerogenic and mutagenic. It is, therefore, necessary for risk assessment not only to determine total chromium, but also to determine chromium species, especially Cr(VI). Hexavalent chromium can be determi...

The toxicity of chromium (Cr) to biota is related to its chemical forms and consequently to the redox conditions of soils. Hexavalent Cr[Cr(VI)] may undergo natural attenuation through reduction processes. In this study, the reduction kinetics of Cr(VI) in seven soils and its relationships with soil properties were investigated with laboratory incubation experiments. The results indicate that t...

The ability of Bacillus sp. MRKV isolated from tannery effluent which shows resistant towards hexavalent chromium potassium dichromate (K2Cr2O7) was evaluated in this study. The bacterial strain was assayed for its reducing ability towards K2Cr2O7. The study revealed that the isolated strain has the ability to reduce the hexavalent chromium and the optimal conditions required for the chromium r...

A mixed plating rinse wastewater containing zinc, hexavalent chromium, trivalent chromium, and cyanide with total dissolved solids of 424 mg/1 was treated by a model consisting of a sand filter and ion exchange columns. A strongly acidic cation resin in hydrogen form and a strongly basic anion resin in hydroxide form were used in the columns as cationic and anionic exchangers, respectively. The...

Biotreatment of hexavalent chromium has attracted widespread interest due to its cost effective and environmental friendliness. However, the difficult separation of biomass from aqueous solution and the slow hexavalent chromium bioreduction rate are bottlenecks for biotechnology application. In this approach, a core-shell structured functional polymer coated magnetic nanocomposite was prepared ...

This study evaluated the toxicity of hexavalent and trivalent compounds of chromium to the pacu, Piaractus mesopotamicus, in acute exposures of 96 h through mortality and histopathological responses. Hexavalent potassium dichromate was more toxic than trivalent compounds of chromium chloride, chromium oxide and chromium carbochelate. Sufficient mortalities occurred only with potassium dichromat...