CO2-assisted 'Weathering' of Steel Slag-Derived Calcium Silicate Hydrate: A Generalized Strategy for Recycling Noble Metals and Constructing SiO2-Based Nanocomposites.

The spent adsorbent loaded by toxic metals is a solid hazardous waste which could cause significant secondary pollution due to potential possible additional release of metal ions. Therefore, the main subject is direct reutilization of spent adsorbents which can further economically and realistically offer new features, like recycling metal adsorbed, or formation of functional SiO2-based nanocomposites. The nanoporous structure and negative surface charges enable steel slag-derived amorphous calcium silicate hydrate (CSH) to retain effectively the incoming metal ions (e. g. Au3+, Ag+, Pd2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Ce3+, Y3+, and Gd3+) by chemisorption. Sparked by natural carbonation 'weathering', which ultimately sequestrates atmospheric CO2 by alkaline silicate minerals to leach calcium from mineral matrix, the decalcification reactions of metal-bearing CSH results in successful recovery of noble metals (Ag, Au, Pd) upon NaOH etching the resultant SiO2 support. Further, SiO2-based heterostructures, containing nanocrystalline metals (e. g. Au0, Ag0, Pd0, Fe0, Co0, Ni0, Cu0, and Zn0) or rare-earth oxides (e. g. CeO2, Y2O3, and Gd2O3), are formed after reduction in H2/Ar (5 vol% H2) flow, which is also very important for the multipurpose immobilization of diverse hybrid materials on SiO2 surface (e. g. Cu0-Ag0@SiO2, Cu0-CeO2@SiO2, and Cu0-Ag0-CeO2@SiO2).

Roles of NOD1/Rip2 signal pathway in carotid artery remodelling in spontaneous hypertensive rats.

Nucleotide-binding and oligomerization domain (NOD) receptor is a member of inherent immunity recognition receptor family. We investigated the NOD1/Rip2 signalling pathway on carotid arterial remodelling in spontaneously hypertensive rats (SHRs). SHRs were treated with NOD1 agonist (iE-DAP), inhibitor (ML130), or normal saline. We determined the NOD1 and Rip2 expression in carotid artery tissues, serum tumour necrosis factor-α (TNF-α) and monocyte chemotactic protein-1 (MCP-1). The carotid artery remodelling in 16-week SHRs was higher than that of 8-week SHRs and 16-week Wistar-Kyoto (WKY) rats. Expression of NOD1, Rip2, MCP-1 and TNF-α in 16-week SHRs was higher than that of 8-week SHRs and 16-week WKY rats. Blood pressure in iE-DAP-treated SHRs was higher than SHR-C group (no treatment), together with MCP-1, TNF-α, NOD1 and Rip2 expression, as well as carotid artery remodelling. In ML130-treated group, these aspects were completely the opposite. Taken together, inhibition of NOD1/Rip2 signalling pathway could delay the vascular remodelling process.

In-situ constructing nanostructured magnesium ferrite on steel slag for Cr(VI) photoreduction.

An innovative method is created for transforming iron-rich RO phase (MgO0.239FeO0.761) on steel slag surface into nanostructured Mg0.04Fe2.96O4 layer. The phase change process is investigated, and it is found that salicylic acid modification and alkaline roasting procedures remarkably increase the specific surface area from 0.46 m2/g (raw steel slag) to 69.5 m2/g (Mg0.04Fe2.96O4), and the generation of Mg0.04Fe2.96O4 enhances the absorption of visible light and Cr(VI) conversion with 2-times increasement than raw steel slag. Surface complexation between H2C2O4 ligands and Fe metal moiety on Mg0.04Fe2.96O4 induces the intramolecular electron transfer under visible light irradiation based on a ligand-to-metal charge transfer mechanism, thus resulting in Cr(VI) photoreduction, and the catalytic efficiency is above 90% for Cr(VI) (40 mg/L) under inherent pH= 5.5 conditions. Moreover, recyclability tests based on magnetic separation show that the photoreactivity is closely related to Mg content of Mg0.04Fe2.96O4 layer where Mg leaching occurs and finally generates cubic spinel configuration Fe3O4. This work highlights the importance of surface functionalization in post-use phases of steel slag in which surface reactivity and application potential can be greatly altered by chemical exposure history and surface transformations. It also provides valuable references for studying the metastable state mechanism of magnesium ferrite photocatalysts.