Surface restructuring of red mud to produce FeO x (OH) y sites and mesopores for the efficient complexation/adsorption of ß-lactam antibiotics.

In this work, iron oxide in the red mud (RM) waste was restructured to produce mesopores with surface [FeO x (OH) y ] sites for the efficient complexation/adsorption of ß-lactam antibiotics. Red mud composed mainly by hematite was restructured by an acid/base process followed by a thermal treatment at 150-450 °C (MRM150, MRM200, MRM300, and MRM450) and fully characterized by Mössbauer, XRD, FTIR, BET, SEM, CHN, and thermogravimetric analyses. The characterization data showed a highly dispersed Fe3+ oxyhydroxy phase, which was thermally dehydrated to a mesoporous α-Fe2O3 with surface areas in the range of 141-206 m2 g-1. These materials showed high efficiencies (21-29 mg g-1) for the adsorption of ß-lactam antibiotics, amoxicillin, cephalexin, and ceftriaxone, and the data was better fitted by the Langmuir model isotherm (R 2 = 0.9993) with monolayer adsorption capacity of ca. 39 mg g-1 for amoxicillin. Experiments such as competitive adsorption in the presence of phosphate and H2O2 decomposition suggested that the ß-lactamic antibiotics might be interacting with surface [FeO x (OH) y ] species by a complexation process. Moreover, the OH/Fe ratio, BET surface area and porosity indicated that this complexation is occurring especially on [FeO x (OH) y ]surf sites contained in the mesopore space.

Role of [FeOx(OH)y] surface sites on the adsorption of ß-lactamic antibiotics on Al2O3 supported Fe oxide.

In this work, [FeOx(OH)y]/Al2O3 composites with different Fe oxyhydroxy contents, i.e. 10, 20 and 50wt% treated at 150, 200, 300 and 450°C were investigated as adsorbents of ß-lactamic antibiotics, i.e. cephalexin, ceftriaxone and especially amoxicillin, from aqueous solutions. The obtained results showed that the nature of the surface Fe(3+) species play a fundamental role on the adsorption process. The most efficient adsorption was obtained for the sample 150Fe50A (50% [FeOx(OH)y] supported in Al2O3 treated at 150°C) whereas the thermal treatment at higher temperatures caused a strong decrease on the adsorption capacity. Mössbauer, XRD, FTIR, Raman, TG-MS, SEM, CHN and BET of the composite 150Fe50A suggested an approximate composition of FeO0.65(OH)1.7 whereas at 450°C strong dehydroxylation process takes place to form FeO1.4(OH)0.21. These results combined with competitive adsorption using amoxicillin mixed with phosphate or H2O2 suggest that the antibiotic molecules adsorb by complexation on surface sites likely based on FeOx(OH)y by the replacement of the labile OH ligands.

Bis(tetra-phenyl-phospho-nium) bis-[N-(trifluoro-methyl-sulfon-yl)dithio-carbimato(2-)-κS,S']zincate(II).

The title salt, (C(24)H(20)P)(2)[Zn(C(2)F(3)NO(2)S(3))(2)], consists of a complex dianion and two tetra-phenyl-phospho-nium cations. The Zn(II) ion displays a distorted tetra-hedral coordination environment with four S atoms from two S,S'-chelated N-(trifluoro-methyl-sulfonyl-)dithio-carbimate anions. In the crystal, besides the ionic inter-action of the oppositely charged ions, inter-molecular C-H⋯O inter-actions between cations and anions are observed. One of the cations inter-acts with an inversion-related equivalent by π-π stacking between phenyl rings, with a centroid-centroid distance of 3.932 (4) Å.

Cognitive dysfunction in post-traumatic obsessive-compulsive disorder.

OBJECTIVE: To investigate whether patients who develop obsessive-compulsive disorder (OCD) after posttraumatic stress disorder, i.e. post-traumatic OCD (PsT-OCD), display a distinctive neurocognitive pattern of dysfunction. METHODS: Patients with PsT-OCD (n = 16), pre-traumatic OCD (PrT-OCD) (n = 18), non-traumatic OCD (NonT-OCD) (n = 67) and healthy controls (n = 17) had their performance compared on the following neuropsychological tests: the Wisconsin Card Sorting Test, the Iowa Gambling Task, the Wechsler Memory Scale Logical Memory, the Brief Visual Memory Test - Revised, and the Wechsler Abbreviated Scale for Intelligence. RESULTS: Patients with OCD, as a group, were characterized by poor set-shifting abilities and impaired verbal and visuospatial memories. Impaired set-shifting abilities were found to correlate with the severity of obsessive-compulsive symptoms in all groups of patients with OCD, with the exception of PsT-OCD. Only patients with PsT-OCD were characterized by impaired visuospatial recognition, which was found to correlate with poor set-shifting abilities in this particular group of patients, but not in individuals with other types of OCD or in healthy controls. CONCLUSIONS: Our study suggests that PsT-OCD is associated with a distinctive pattern of neurocognitive dysfunction, thus providing support for a different subtype of OCD.