in parts of desert regions in our country, groundwater is the only source of fresh water and due to geological formation, the concentration of hexavalent chromium in groundwater will reach beyond the allowed limits. furthermore, previous studies showed that hexavalent chromium is a cancerous substance for humans and toxic for other organisms. in this study the removal of hexavalent chromium fro...

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...

Reaction of potassium dichromate with sodium ascorbate was studied by EPR spectroscopy at room temperature, in 0.10 M N-[2-hydroxyethyl]piperazine-N'-[2-ethanesulfonic acid] (HEPES), phosphate, cacodylate, and tris(hydroxymethyl)aminomethane hydrochloride (Tris.HCl) buffers at pH 7.0, in the presence of 0.10 M spin trap [5,5-dimethyl-1-pyrroline 1-oxide or 2-methyl-N-(4-pyridinylmethylene)-2-pr...

Chromium exists in many different oxidation states in the environment, Cr(VI) and Cr(III) being the most stable forms. Chromium has been known for over 100 years to be a human carcinogen. The greatest risk of cancer from chromium exposure is associated with Cr(VI). Cr(VI) enters cells via the sulfate anion transporter system and is reduced to intermediate oxidation states, such as Cr(V) and Cr(...

The potential to remove chromium(VI) from aqueous solutions through biosorption using coffee husk was investigated. The effects of pH, contact time, initial concentration and adsorbent dosage on the adsorption of Cr(VI) were studied. The data obeyed Langmuir and Freundlich adsorption isotherms. The Langmuir adsorption capacity was found to be 44.95 mg/g. The Freundlich constants Kf and n were 1...

the objective of this work focuses on the use of a new natural lignocellulosic material based on palm stems for adsorbing of hexavalent chromium (cr(vi)) in water. the palm stems powder (psp) was characterized using different techniques. the influencing factors on the adsorption of cr(vi) ions was investigated such as ph. the results show that the increase of the temperature and the initial ads...

Title of dissertation: USE OF TARTARIC ACID AND ISOPROPYL ALCOHOL IN THE REDUCTION OF HEXAVALENT CHROMIUM AND APPLICATION TO CHROMIUM CONTAMINATED SOILS AND CHROMITE ORE PROCESSING RESIDUE Dominic A. Brose, Doctor of Philosophy, 2012 Dissertation directed by: Professor Bruce R. James Department of Environmental Science and Technology Although chromium (Cr) is a naturally occurring metal, in the...

The increasing industrial development of recent decades has lead to the production of increasing quantities of waste containing heavy metals, elements often harmful to the environment, which in the past were not properly disposed of, thus inducing soil and groundwater pollution. In particular, chromium (Cr) and its derivatives are largely used in industries such as textiles, electronics, metall...