In order to develop a green and efficient nano suppressant for aluminum (Al) dust explosion, MCN with layered structure was synthesized with low-cost urea as precursor via simple calcination technology . The suppression performance of MCN on the flame propagation of 30 μm and 5 μm Al dust with the concentration of 1000 g/m 3 was experimentally studied. Results showed that with the addition of MCN increasing, the flame luminous intensity , flame propagation velocity and fluctuating trend of mixture-Al dust were greatly decreased. After adding 500 g/m 3 and 700 g/m 3 to 30 μm and 5 μm Al dust, the average flame propagation velocities declined by 73.24 % and 94.07 % separately. The minimum inerting concentration of 30 μm and 5 μm Al dust was 600 g/m 3 and 900 g/m 3 . Explosion residuals were analyzed to further reveal the suppression mechanism of MCN in detail. The good performance of MCN provided a potential direction to develop efficient suppressants on the suppression of Al dust explosions to improve process safety.
In this study, a novel nitrogen modified carbon quantum dots (NCDs) decorated graphite carbon nitride /molybdenum (Mo) heterojunction photocatalyst (MCN/NCDs) was obtained by in-situ calcination and physical deposition, and applied as peroxymonosulfate (PMS) activators for tetracycline (TC) removal under visible light. It was found that the MCN/NCDs as PMS activation catalyst exhibited outstanding removal efficiency under visible light assistance and nearly 98.4% of TC was degraded within 60 min. The analysis data of photochemistry demonstrated that the introduction of NCDs could significantly improve the visible-light utilization, narrow the band gap and increase the separation of photogenerated electron-hole pairs. The results of radical capture experiment and electron spin resonance test (ESR) suggested that the order of active species contributing to TC degradation in vis/PMS/MCN/NCDs system was O 2 – > h + > OH > 1 O 2 > SO 4 − . Moreover, the MCN/NCDs composite exhibited excellent stability with over 98% activity retention for 5 cycles and superior catalytic efficiency in four real water matrix. Finally, the underlying degradation mechanism and toxicity assessment were proposed in detail. This work provided a new perspective on the design of excellent activity g-C 3 N 4 composite catalysts and elucidated a promising potential strategy for efficient contaminated water treatment via PMS activation process.
Fan Yang,Guoyu Ding,Jin Wang,Zihan Liang,Boru Gao,Mengmeng Dou,Ce Xu,Shuming Li
Mesoporous graphitic carbon nitride (MCN) photocatalyst was blended in polyvinylidene fluoride (PVDF) membrane through immersion-precipitation phase transformation. Various techniques were adopted to characterize the structure and morphology of MCN-PVDF hybrid membrane, which indicated that MCN was successfully integrated in PVDF. The MCN 80 -PVDF membrane exhibited enhanced hydrophilicity and antifouling properties. As the amount of MCN addition increased, the contact angle of membranes decreased from 68.33° to 57.12°, whereas the flux recovery rate increased by 28% as compared to the pristine PVDF. Meanwhile, MCN-PVDF membrane possessed photocatalytic, self-cleaning and antimicrobial activities. The MCN 80 -PVDF membrane was used to degrade cefotaxime (CFX) under sunlight irradiation. After five cycles of experiments, the degradation rate of CFX remained 97.4%. Additionally, MCN 80 -PVDF membrane achieved 3 log of E. coli inactivation under visible light irradiation for 4 h. The photogenerated h + and reactive oxidative species were the primary reason for organics’ degradation and bacterial inactivation. In summary, the prepared hybrid MCN 80 -PVDF membrane with sunlight irradiation exhibited great potential for the treatment of real wastewater .
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