In this study adsorption of Cr(VI) from aqueous solution by Fe3O4 nanoparticles was investigated. Desorption process and recovery of nanoparticles using different solutions were then carried out, and it was observed that NaOH (0.5M) can remove 90% of adsorbed chromium ions. Following the completion of adsorption/ desorption cycles, it was determined that nanoparticles have still had a high abil...

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...

Biosorption is a process, which represents a biotechnological innovation as well as a cost effective excellent tool for removing heavy metals from aqueous solutions. The kinetics and equilibrium of the biosorption of Chromium (VI) from aqueous solution were investigated using immobilized mixed biosorbents of Annona squamosa seeds and Aspergillus niger in a batch system. The biosorption characte...

The construction and performance characteristics of a novel chromate ion-selective membrane sensor are described and used for determining chromium(III) and chromium(VI) ions. The sensor is based on the use of a rhodamine-B chromate ion-associate complex as an electroactive material in a poly(vinyl chloride) membrane plasticized with o-nitrophenyloctyl ether as a solvent mediator. In a phosphate...

Arthrobacter viscosus biomass was used for Cr(VI) biosorption. The effect of pH on Cr(VI) reduction and removal from aqueous solution was studied in the range of 1-4. The Cr(VI) removal involves both redox reaction and adsorption of metal ions on biomass surface. The removal rate of Cr(VI) was enhanced by very acid conditions, while higher solution pH values favored the removal of total chromiu...

The adsorption of chromium(VI) ions from aqueous solutions has been investigated on Neem sawdust (NS), Mango sawdust (MS), Wheat shell (WS), Sugarcane bagasse (SB) and Orange peel (OP). The adsorbent which showed highest chromium(VI) removal was Neem sawdust. The influence of pH, contact time, biomass dosage and initial metal concentration on biosorption was investigated. The biosorptive capaci...

Copper and hexavalent chromium are heavy metals that are harmful to human health. Natural adsorbent chitosan, due to its considerable properties such as the presence of functional groups of –NH2 and -OH, non-toxicity, low cost, and biocompatibility, has gained much attention in pollutant removal. Therefore, in the present study, adsorption of chromium (VI) and copper (II) ions was conducted in ...

A chromium-resistant fungus isolated from contaminated air with industrial vapors can be used for reducing toxic Cr(VI) to Cr(III). This study analyzes in vitro reduction of hexavalent chromium using cell free extract(s) of the fungus that was characterized based on optimal temperature, pH, use of electron donors, metal ions and initial Cr(VI) concentration in the reaction mixture. This showed ...

Poly(1,3-thiazol-2-yl methacrylamide-co-4-vinyl pyridine-co-divinylbenzene) was prepared and used as a sorbent for the solid-phase extraction of Cr(VI) ions from aqueous solution. Two forms of chromium showed different exchange capacities at different pH values; Cr(VI) was selectively retained especially at pH 2. The total chromium was determined after the oxidization of Cr(III) to Cr(VI) by po...

The activated sludge has been acclimatized with chromium (VI) ions from 5 mg/L to 20 mg/L. It is observed that the chromium removal percentage, COD removal and mixed liquor suspended solid (MLSS) decrease with the increase in dilution rate. Maximum food to microorganisms ratio (F/M) is found to be 0.19. When initial metal ion concentration increases from 5 mg/L to 20 mg/L, the chromium removal ...