Highly efficient Cu2O@CuxFeyO4 nanohybrid catalyst for the degradation of emerging pollutants

Cu2O@CuxFeyO4 nanohybrids (NHs) have been electrosynthesized by a simple and environmentally safe method to be used as catalysts for tetracycline degradation. NHs shown an average diameter of 14(5) nm and exhibit high crystallinity with spherical morphology. XPS results demonstrate a cuprite-enriched surface; meanwhile, the inner layer is composed by a nonstoichiometric copper spinel structure. The degradation has been monitored by UV–Visible spectroscopy, TOC analysis, and HPLC. The electrochemical characterization demonstrates the synergetic effect of Fe3+/Fe2+ and Cu2+/Cu+ coupling to enhance the activation of persulfate. This effect results in a greater degradation efficiency of NHs than other catalysts, namely, CuxOy, Fe3O4, and a mixture of both and Cu2O. It has been found that a previous adsorption stage before degradation does not improve the elimination of the pollutant and its length in time, with a TOC reduction of 72.6 % in 2 h. Conversely, conducting the oxidative process in a direct step resulted in a more rapid and efficient process, 82.3 % of reduction in 1 h. Through this method, the catalyst reutilization resulting in a decrease of 50 % in TOC degradation from the third use, while the TCY concentration degraded remains almost constant. This reduced catalytic activity with use might be a consequence of 1) the absence of the single Cu-oxide layer due to the leaching of mainly Cu ions but also Fe ions during the degradation tests, and, 2) the passivation of the outermost layer, mainly covered by C–O species and OH groups, which hinders access to active catalyst sitesThis research was funded by the Madrid Government (Comunidad de Madrid-Spain) under the Multiannual Agreement with Universidad Autonoma ´ de Madrid in the line of action encouraging youth research doctors, in the context of the V PRICIT (Regional Programme of Research and Technological Innovation) (SI1-PJI-2019-00366) and by the Spanish Ministry of Science and Innovation under project PID2021- 123431OB-I00. FJP acknowledges financial support from Grant PID2021-126169OB-I00 funded by MCIN/AEI/10.13039/5011000110 33 and by “ERDF A way of making Europe”. The authors would like to acknowledge to L. Gutierrez and the Advanced Microscopy Laboratory (INA-Universidad de Zaragoza) for access to their instrumentation and expertis

Adsorption of chromium(VI) onto electrochemically obtained magnetite nanoparticles

Well-dispersed magnetite nanoparticles of different sizes between 15 and 43 nm were synthesized by an electrochemical method in a controlled manner by simply changing the synthesis temperature. These nanoparticles were used as a reusable adsorbent to remove Cr(VI) from aqueous solution. The recovery efficiency was found to be highly dependent on environmental parameters, such as temperature and pH. In addition, it was demonstrated that the initial concentrations of both Cr(VI) and magnetite nanoparticles strongly influence the removal capability of these nanomaterials. Remarkably, the nanoparticle size has a key role on the Cr(VI) adsorption efficiency, which gradually increases as the diameter decreases due to the augmentation of the surface area. The low aggregation in the case of small particles that results from the low magnetization saturation values also contributes to the enhancement of the surface area available for Cr(VI) adsorption. In contrast, nanoparticles with larger sizes are more easily manipulated by a magnet, and the efficiency is largely maintained after five cycles. The adsorption process fits the Langmuir isotherm model well, and the reaction was found to follow a pseudo-second-order rate.The authors are grateful to the Spanish Ministry of Science and Innovation (MAT2012-37109-C02-02, MAT2013-47878-C2-1-R and CSD2008-00023)

NCX-701 (nitroparacetamol) is an effective antinociceptive agent in rat withdrawal reflexes and wind-up

1. Non-steroidal anti-inflammatory drugs (NSAIDs) are effective anti-inflammatory and analgesic drugs although they also induce unwanted side effects due to the inhibition of the physiological effects regulated by prostaglandins. This has led to the search for new compounds with fewer side effects, such as the nitro-NSAIDs (NO-NSAIDs). Paracetamol is an analgesic drug devoid of some of the side effect of the NSAIDs but without anti-inflammatory activity. NCX-701 is a nitric oxide releasing version of paracetamol with anti-inflammatory and analgesic properties. 2. We have tested, in the single motor unit technique, the antinociceptive actions of intravenous cumulative doses of NCX-701 vs paracetamol, studying their antinociceptive effects in responses to noxious mechanical and electrical stimulation (wind-up). 3. Paracetamol did not induce any significant effect at the doses tested (maximum of 480 μmol kg(−1), 72.5 mg kg(−1)). NCX-701 however was very effective in reducing responses to noxious mechanical stimulation (32±10% of control response) and wind-up (ED(50) of 147±1 μmol kg(−1), 41.5±0.3 mg kg(−1)). The inhibition was not reversed by 1 mg kg(−1) of the opioid antagonist naloxone. In control experiments performed with either the vehicle or the NO donor NOC-18, no significant changes were observed in the nociceptive responses studied. 4. We conclude that NCX-701 is a very effective non-opioid antinociceptive agent in normal animals and its action is located mainly at central areas. The antinociceptive effect was not due solely to the release of NO