Reaction Of Iron Ions Research Articles

Fe3O4 nanoparticles loading on cow dung based activated carbon as an efficient catalyst for catalytic microbubble ozonation of biologically pretreated coal gasification wastewater

Cow dung based activated carbon was successfully modified by Fe3O4 nanoparticles as the novel catalyst (Fe3O4 nanoparticles@CDAC) to improve the microbubble ozonation treating biologically pretreated coal gasification wastewater (BPCGW). When the pH, ozone dosage, ozone bubble diameter and catalyst dosage of the ozonation were 7, 0.4 L/min, 5 μm and 3 g/L, the chemical oxygen demand (COD) removal efficiency reached 74% and the ratio of biochemical oxygen demand in five days/COD (BOD5/COD) increased from 0.04 to 0.52, which were attributed to the electron transfer of Fe2+ and Fe3+ in Fe3O4 and enhanced hydroxyl radicals generation by the reaction of iron ions and ozone. Meanwhile, benzene derivatives, naphthalene and aromatic proteins were significantly removed while multiple chain hydrocarbons and their derivatives composed the main residual organic matters. The catalytic activity was slightly decreased even the catalyst has been reused for five times. Therefore, catalytic microbubble ozonation using Fe3O4 nanoparticles@CDAC represented excellent performance treating BPCGW and it is a promising process for wastewater advanced treatment.

Synthesis, structural characterization, and magnetic properties of the metallamacrocycle [Fe6(C11H11N2O3)6(C4H9NO)6

The 18-metallacrown-6 metallamacrocycle [Fe6(pmshz)6(C4H9NO)6] has been synthesized by the self-assembly reaction of iron ions with N-substituted salicylhydrazide ligands. Six Fe(III) ions and six deprotonated N-propanoyl-4-methylsalicylhydrazide (H3 pmshz) ligands construct a planar 18-membered ring based on Fe–N–N–Fe linkage. Because of the coordination, the ligand enforces the stereochemistry of the Fe(III) ions as a propeller shape with alternating …ΔΛΔΛ… configurations. There is a strong antiferromagnetic exchange interaction between the paramagnetic iron centers.

Gas-phase ion/ion interactions between peptides or proteins and iron ions in a quadrupole ion trap

The gas-phase ion/ion reactions of iron ions with oppositely charged peptide and protein ions were studied in a quadrupole ion trap. Both Fe + and FeCO 2 − were investigated as possible reactant ions for gas-phase cleavage of peptide and protein ions. Several types of reaction products were observed. Charge exchange lowered the charge states of the proteins. Attachment resulted in a complex of the protein ion and the iron ion. In some cases bonds were broken in the protein ions, but it is unclear whether this is due to an insertion of the iron ion into a bond or due to the energetic reaction of oppositely charged species. Some preference was observed for bond cleavage near sulfur. Two disulfide bonds were broken in one case, and bonds adjacent to a cysteine residue were broken in another.

Inactivation of α 1 -antiproteinase by hydroxyl radicals The effect of uric acid

The elastase-inhibitory activity of α,-antiproteinase is inactivated by hydroxyl radicals ( .OH) generated by pulse radiolysis or by reaction of iron ions with H 2O 2 in the presence of superoxide or ascorbate. Uric acid did not protect α 1-antiproteinase against inactivation by .OH in pulse radiolysis experiments or in the superoxide/iron/H 2O 2 system, whereas it did in systems containing ascorbic acid. We propose that radicals formed by attack of .OH on uric acid are themselves able to inactivate α 1 1-antiproteinase, but that these uric acid radicals can be ‘repaired’ by ascorbic acid.