RESUMEN
The multistage reclamation of materials has made contributions to sustainable development, but further progress is still sought after. In this work, functionalized seaweed-based composites were successfully prepared and utilized in multiple stages. Specifically, Co2+-containing alginate hydrogels (CHB-Co2+) prepared by sol-gel self-assembly and adsorption method using interior/exterior co-functionalized calcium alginate as raw materials were utilized for efficient reduction of p-nitrophenol. After coupling with freeze-drying and carbonization procedures, a high-performance Co/N co-doped carbonaceous microwave absorber was obtained and investigated in detail. By virtue of unique 3D interconnected network, heterogeneous interfaces and doped heteroatom N species, by which endowing the absorber with optimal impedance matching and attenuation ability, as-fabricated NC-Co-700 exhibited prominent microwave absorption performance with -54.2 dB of RLmin at 6.4 GHz and 5.3 GHz of maximum absorption bandwidth (from 12.7 to 18.0 GHz). Additionally, in view of the dielectric loss and magnetic loss caused by the synergy effect among the functional components, the underlying absorption mechanism was proposed. This work provided a novel idea for designing biomass-based functional materials and simultaneously achieved economic benefits through the rational utilization of other products in the preparation process.
Asunto(s)
Alginatos/química , Cobalto/química , Hidrogeles/química , Microondas , Absorción de Radiación , Catálisis , Nitrofenoles/química , Oxidación-Reducción , Algas Marinas/químicaRESUMEN
The rational optimization of catalytic composites with excellent catalytic activities and long-term cycling stabilities for environmental remediation is still maintained as highly desired but is an ongoing challenge. Here, seaweed-derived N-doped versatile carbonaceous beads with Co x O y (Co-NC-0.25-700 °C) are employed as a novel catalyst to activate peroxymonosulfate (PMS) for methylene blue (MB) degradation. Profiting from the improved structure-activity relationship and the synergistic effects between the "egg-box" structure and the Co x O y loaded on the N-doped carbonaceous beads, Co-NC-0.25-700 °C exhibited relatively high performance and comparative long-term stability. The universal applicability of Co-NC-0.25-700 °C was investigated by degrading other types of organic pollutants in various systems. For this type of newly fabricated high-performance versatile composites, structure-property relationships were plausibly proposed. Notably, the degradation efficiency and the catalyst structure could be tailored by the amount of polyethyleneimine (PEI) introduced in the preparation process and by the pyrolysis temperature. More favorably, the coupling of the magnetic properties and bead-like shape endows the resultant composites with remarkable reusability and recyclability, as compared to powder state materials. Another interesting finding is that MB degradation over Co-NC-0.25-700 °C is minimally affected by common ions (Cl-, NO3 -, SO4 2-, etc.), and holds a certain catalytic activity under the background conditions of two simulated real water conditions (running water and seawater). Of particular interest, a microreactor filled with Co-NC-0.25-700 °C was utilized as a verification model for practical applications of the reaction in continuous-flow. More far-reaching, the simulations of actual water conditions and the design of a continuous-flow reactor represent a giant step towards universal applications for organic pollution treatment.
RESUMEN
BACKGROUND: The high prevalence of transfusion-transmitted infections (TTIs) is causing serious harm to human health worldwide. The aim of this research was to assess the prevalence and influencing factors of TTIs in Southwest China. METHODS: A retrospective study of blood donor records from January 2008 to December 2015 was conducted. All samples were screened for HBV, HCV, HIV and syphilis. The donor's data was recorded and analyzed statistically using SPSS software. RESULTS: We revealed that the prevalence of TTIs showed a decreasing trend from 2.39 to 1.98%, and this was slightly lower than that in other regions of China. Syphilis infection was the most serious issue among blood donors in Southwest China, which demonstrated a significantly higher rate than that in other areas of China. The high infection rate of the female and farmer groups in rural regions is worth noting. The logistic regression model showed that age, occupation and donor category was the influential factors for TTIs. CONCLUSIONS: The overall prevalence of TTIs demonstrated a decreasing trend from 2008 to 2015 in Southwest China, but there is still a sufficient threat to blood safety, and more efforts are needed to further guarantee blood safety in China.