background : hexavalent chromium ( cr (vi)) is an important contaminant in surface and groundwater and its removal from contaminated water and wastewater has received interest in recent years. this study aimed to explain the removal process of cr (vi) from aqueous solution using nano hydroxyapatite (n-hap) as an adsorbent material. methods: cr (vi) removal experiments with the prepared n-hap we...

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 ...

the reaction between ni(ii), co(ii), cr(iii) bitrates, ni(ii) chloride and ambidentate a-keto ylide benzoylmethylenetriphenylphosphine (bppy) resulted in isolation of [ni(bppy)2](no3)2.2h2o, [ni(bppy)2]cl2, [co(bppy)2](no3)2 and [cr(bppy)3](no3)3; 2h2o. the compounds were characterized by elemental analyses and infrared 1hnmr spectroscopy, molar conductivity in solution and molecular weight mea...

This paper reports the evaluation of adsorbing Cr (VI) ions on sorbent prepared from chitosan (CHT), a versatile derivative of chitin, and dodecyl amine modified locally available kaolinite clay (Bijoypur clay) (MC) that has excellent mechanical properties and great resistance to chemical and biological attack. The effect of the initial metal ion concentration, solution pH, contact time, and ad...

crown ethers 12-crown-4 (12c4), benzo-15-crown-5 (b15c5), 18-crown-6 (18c6), nitrobenzo-18-crown-6 (nb18c6) dibenzo-18-crown-6 (db18c6) and dicyclohexyl-18-crown-6 (dc18c6), dissolved in dichloromethane, are able to form oxonium-ion complexes in contact with aqueous sulfuric and hydrochloric acid solutions. this ability allows the transfer of cr(vi) oxanions from the acid media, through an orga...

A nitrogen-doped magnetic graphene oxide (NMGO) was synthesized and applied as an adsorbent to remove Cu(II) and Cr(VI) ions from aqueous solutions. The individual and combined effects of various factors (A: pH, B: temperature, C: initial concentration of metal ions, D: CaCl2, and E: humic acid [HA]) on the adsorption were analyzed by a 25-1 fractional factorial design (FFD). The results from t...