M-N3 Configuration on Boron Nitride Boosts Singlet Oxygen Generation via Peroxymonosulfate Activation for Selective Oxidation.

Singlet oxygen (1O2) is an essential reactive species responsible for selective oxidation of organic matter, especially in Fenton-like processes. However, due to the great limitations in synthesizing catalysts with well-defined active sites, the controllable production and practical application of 1O2 remain challenging. Herein, guided by theoretical simulations, a series of boron nitride-based single-atom catalysts (BvBN/M, M=Co, Fe, Cu, Ni and Mn) were synthesized to regulate 1O2 generation by activating peroxymonosulfate (PMS). All the fabricated BvBN/M catalysts with explicit M-N3 sites promoted the self-decomposition of the two PMS molecules to generate 1O2 with high selectivity, where BvBN/Co possessed moderate adsorption energy and d-band center exhibited superior catalytic activity. As an outcome, the BvBN/Co-PMS system coupled with membrane filtration technology could continuously transform aromatic alcohols to aldehydes with nearly 100 % selectivity and conversion rate under mild conditions, suggesting the potential of this novel catalytic system for green organic synthesis.

Separation and reutilization of heavy metal ions in wastewater assisted by p-BN adsorbent.

Extracting heavy metal ions from wastewater has significant implications for both environmental remediation and resource preservation. However, the conventional adsorbents still suffer from incomplete ion removal and low utilization efficiency of the recovered metals. Herein, we present an extraction and reutilization method assisted by porous boron nitride (p-BN) containing high-density N atoms for metal recovery with simultaneous catalyst formation. The p-BN exhibits stable and efficient metal adsorption performance, particularly for ultra-trace-level water purification. The distribution coefficients towards Pb2+, Cd2+, Co2+ and Fe3+ can exceed 106 mL g-1 and the residual concentrations that reduced from 1 mg L-1 to 0.8-1.3 µg L-1 are much lower than the acceptable limits in drinking water standards of World Health Organization. Meanwhile, the used p-BN after Co ion adsorption can be directly adopted as a high-efficiency catalyst for activating peroxymonosulfate (PMS) in organic pollutant degradation without additional post-treatment, avoiding the secondary metal pollution and the problems of neglected manpower and energy consumption. Moreover, a flow-through multistage utilization system assisted by p-BN/polyvinylidene fluoride (PVDF) membrane is constructed for achieving both metal ion separation and reutilization in the removal of organic pollutants, providing a new avenue for sustainable wastewater remediation.

A polymer tethering strategy to achieve high metal loading on catalysts for Fenton reactions.

The development of heterogenous catalysts based on the synthesis of 2D carbon-supported metal nanocatalysts with high metal loading and dispersion is important. However, such practices remain challenging to develop. Here, we report a self-polymerization confinement strategy to fabricate a series of ultrafine metal embedded N-doped carbon nanosheets (M@N-C) with loadings of up to 30 wt%. Systematic investigation confirms that abundant catechol groups for anchoring metal ions and entangled polymer networks with the stable coordinate environment are essential for realizing high-loading M@N-C catalysts. As a demonstration, Fe@N-C exhibits the dual high-efficiency performance in Fenton reaction with both impressive catalytic activity (0.818 min-1) and H2O2 utilization efficiency (84.1%) using sulfamethoxazole as the probe, which has not yet been achieved simultaneously. Theoretical calculations reveal that the abundant Fe nanocrystals increase the electron density of the N-doped carbon frameworks, thereby facilitating the continuous generation of long-lasting surface-bound •OH through lowering the energy barrier for H2O2 activation. This facile and universal strategy paves the way for the fabrication of diverse high-loading heterogeneous catalysts for broad applications.

Nitrogen-doped carbon nanosheets with Fe-based nanoparticles for highly efficient degradation of antibiotics and sulfate ion enhancement effect.

Developing Fe-based catalysts with high-effective and environmentally friendly features in Fenton-like system for treating wastewater is still a challenge. Novel nitrogen-doped carbon nanosheets with Fe0/Fe3C nano-particles (Fe@NCS-900) were prepared through a simple solvent-free strategy by pyrolyzing the mixture of 2,6-diaminopyridine and ferric chloride hexahydrate under 900 °C. The Fe@NCS-900 possessed almost 100% removal efficiency and 66.5% mineralization rate for the degradation of CBZ in 10 min. Moreover, the Fe@NCS-900 exhibited an apparent first-order constant as high as 0.8809 min-1, which is 22 and 29 times higher than that of the commercial Fe0 and traditional Fenton system, respectively, which could be attribute to the high graphitization degree and rich nitrogen content. Besides, the results of the radical quenching experiments, electron paramagnetic resonance (EPR) and the probe experiments demonstrated that a large number of high valent iron species (Fe (IV)) besides singlet oxygen (1O2) and superoxide radicals (O2•-) existed and contributed to the CBZ degradation. More interestingly, the addition of coexisting anion SO42- in the reaction system could significantly boost the concentration of •OH and SO4•- by 28.3 times and 9.7 times, respectively, resulting in the increase of the apparent first-order constant by 5.9 times (5.1733 min-1), which was entirely different from previous reports that SO42- had no effect on the catalytic activity or even displayed slightly inhibitory effect. In addition, the catalyst exhibited broad pH adaptability in the pH range of 2-9. The intermediate products of CBZ degradation were investigated by liquid chromatography mass spectrometry (LC-MS) and the degradation pathway was proposed. This paper provides new insights for developing a promising Fe-based nitrogen-doped catalyst for practical wastewater treatment.

Effects of bisoprolol in combination with trimetazidine on the treatment of heart failure and concomitant chronic obstructive pulmonary disease.

OBJECTIVE: To evaluate the effects of bisoprolol combined with trimetazidine on the treatment of heart failure patients having concomitant chronic obstructive pulmonary disease (COPD); in comparison with control group treated with standard therapy only. METHODS: A total of 120 heart failure patients having concomitant COPD were selected and randomly divided into a control group and a treatment group according to different treatment methods (n=60). The control group was given continuous low flow oxygen inhalation and inotropic agents, and their cardiac stress was also reduced. The treatment group was treated with bisoprolol fumarate and trimetazidine in addition to treatment for COPD. For all patients, blood gas analysis and parameters reflecting cardiac function were measured respectively before and after treatment. The respiratory symptoms (cough, sputum, polypnea, gasp, dyspnea), limitation of motion (daily life, household duties, entertainment, sports), disease impacts (social contact, emotion, anxiety) and St. George's Respiratory Questionnaire (SGRQ) total scores were observed using SGRQ. RESULTS: The oxygen partial pressure (PaO2) and partial pressure of carbon dioxide (PaCO2) of the treatment group after treatment were significantly different from those before treatment. After treatment, peak E, E/A and IVEF were increased by 41%, 44% and 16% respectively, but peak A, LVPWT/mm and IVST/mm were significantly reduced. The differences in the respiratory symptoms, limitation of motion, disease impacts and SGRQ total scores were statistically significant compared with those before treatment (P<0.05) and those of the control group (P<0.05). CONCLUSION: Combining bisoprolol with trimetazidine in the treatment of heart failure complicating COPD can effectively improve blood gas indices, left ventricular systolic and diastolic functions and the quality of life, thereby alleviating clinical symptoms.