The new magnetic amine-functionalized graphene oxide (Fe3O4-GO-NH2) nanocatalyst was prepared through the reaction of 3-aminopropyltriethoxysilane (APTES) with magnetic graphene oxide (Fe3O4-GO). It was characterized by XRD, TEM, SEM, FT-IR and EDX techniques. The intrinsic carboxylic acids on the edges of Fe3O4-GO alo...

The microstructures of chromium and iron borides formed during laser surface alloying of AISI 1045 steel with CrB were examined by transmission electron microscopy combined with selected-area electron diffraction and X-ray-dispersive spectroscopy. It was found that the heavily faulted (Cr, Fe)2B phase contains a microsyntactic existence of several polytypes, including one-dimensionally disorder...

This work investigated the effect of co-existing organic matters on aqueous Cr(VI) reduction by electrodeposited zero-valent iron (ED Fe(0)) at neutral pH. The ED Fe(0) prepared in a solution containing mixture of saccharin, L-ascorbic acid and sodium dodecyl sulfate showed higher activity in reducing the aqueous Cr(VI) at neutral pH than that prepared without any organic presence. XRD and SEM ...

Ferritin concentrates iron as a hydrous ferric oxide in a protein cavity (8 nm in diameter) by using eight pores along the threefold symmetry axes of the octahedral supramolecular structure. The role of ligand exchange in the entry of Fe(II) hexahydrate into ferritin protein has been studied with [Cr(TREN)(H2O)(OH)] [TREN N(CH2CH2NH2)3], a model for Fe(H2O)6 with only two exchangeable ligands. ...

The mechanisms of photo-catalytic reduction of Cr(VI) were investigated in acidic solutions with and without Fe(III). In a system without Fe(III), no Cr(VI) reduction was observed in dark conditions; conversely, under light conditions, the reduction reaction rate increased to 0.011 and 0.020microM min(-1) at pH 2 and pH 1, respectively, indicating the occurrence of Cr(VI) photo-reduction. The C...

Cr(VI) is an important contaminant found at sites where chromium ore processing residue (COPR) is deposited. No low cost treatment exists for Cr(VI) leaching from such sites. This study investigated the mechanism of interaction of alkaline Cr(VI)-containing leachate with an Fe(II)-containing organic matter rich soil beneath the waste. The soil currently contains 0.8% Cr, shown to be present as ...

A serial enrichment culture has been grown in an alkaline Fe(III)-citrate-containing medium from an initial inoculum from a soil layer beneath a chromium ore processing residue (COPR) disposal site where Cr(III) is accumulating from Cr(VI) containing leachate. This culture is dominated by two bacterial genera in the order Clostridiales, Tissierella, and an unnamed Clostridium XI subgroup. This ...