Degradation of Orange II by Fenton reaction using ilmenite as catalyst.

This work deals with the degradation of the azo-dye Orange II (OII) by a heterogeneous process with dark Fenton. Natural and purified ilmenites from Colombian soil were used as catalysts. The catalysts have different physicochemical properties and are basically composed of TiO2 and Fe2O3. Ilmenites (FeTiO3), raw materials highly available at low cost, were studied by means of conventional metallography (polished grain mounts), as well as BET, XRD, and XRF in order to determine their possible source area and the factors that influence their use as a catalyst for OII degradation. The pH, the ilmenite amount, the initial CH2O2, and the temperature of the reaction system were studied. Complete degradation of dye was observed within 7 h, while 90 % of OII was removed in 7 h using Cumaribo Ilmenite. Graphical Abstract ᅟ.

Supplementation of collagen scaffolds with SPARC to facilitate mineralization.

The extracellular matrix-associated protein, SPARC (Secreted Protein Acidic and Rich in Cysteine) is known to play a role in the mineralization of collagen in bone formation. The objectives of this study were to determine: 1) if SPARC supplementation of type 1 collagen scaffolds in vitro facilitated the binding of pre-formed HA nanoparticles added to the scaffolds; 2) if SPARC supplementation of the scaffolds enhanced the uptake of calcium and phosphorus from calcium phosphate solutions; and 3) if pretreatment in a calcium phosphate solution enhanced the subsequent binding of the nanoparticles. A related objective was to begin to determine the behavior of mesenchymal stem cells in the scaffolds when the constructs were grown in osteogenic medium. The calcium and phosphorus contents of the scaffolds were evaluated by inductively coupled plasma analysis, and the elastic modulus of the scaffolds determined by unconfined compression testing. Scaffolds were seeded with goat bone marrow-derived mesenchymal stem cells and the cell-seeded constructs grown in osteogenic medium. Supplementation of the scaffolds with as little as 0.008 % SPARC (by wt. of collagen) resulted in an increase in the binding of hydroxyapatite nanoparticles to the scaffold, but had no effect on incorporation of calcium or phosphorus from a calcium phosphate solution. The incorporation of hydroxyapatite nanoparticles into the scaffolds did not result in an increase in modulus. Supplementation of the scaffolds with SPARC and the increase in the binding of hydroxyapatite nanoparticles did not affect the proliferation of mesenchymal stem cells.