Weirui Chen,Siyou Fu,Xukai Li,Jing Wang,Xunan Ning,Liying Bin,Ping Li,Bing Tang,Laisheng Li
Photocatalytic ozonation (PCO) was a novel water treatment method, but the low photo-generated electron ( e - ) utilization and ambiguous ROS formation mechanism restrained its performance. Herein, C vacancy and F co-decorated g-C 3 N 4 (FCN_Cv) was designed to accelerate the PCO performance with sodium p -perfluorinated nonoxybenzenesulfonate (OBS) acting as model pollutant. Comparative characterizations revealed that FCN_Cv remained the inherent structure of g-C 3 N 4 (BCN), and had an enhanced conduction band potential, narrower band gap and longer e - lifetime. FCN_Cv exhibited the greater activity over BCN, with 99.3 % OBS removal in 30 min but only 78.3 % for BCN during PCO process. •OH was the main ROS for degrading OBS. The greater •OH yield was obtained by FCN_Cv PCO process because of the increase of e - utilization. On one hand, the two electrons reduction of O 2 into H 2 O 2 on FCN_Cv was accelerated, which triggered the peroxone reaction between photogenerated-H 2 O 2 and O 3 . On the other hand, the direct one electron reduction of O 3 by e - also accounted for •OH generation. 17 kinds of intermediates were detected and the OBS degradation routes were inferred, which was involved with hydroxylation, C-O cleavage and aromatic ring opening reactions. Overall, this study demonstrated the feasibility of decorating F element and C vacancy on g-C 3 N 4 in enhancing e - utilization and •OH generation during PCO process as well as deepened the understanding of fate of OBS in PCO process.
NH2-MIL-53(Al) nanorods studded with F− were successfully synthesized via coordination modulation with HF as a modulator. The investigation of the growth mechanism pointed out that F− plays a key role in the formation process. The incorporation of F− into the framework of NH2-MIL-53(Al) not only made the crystal morphology tunable but also magnified the fluorescence enhancement performance of NH2-MIL-53(Al) in water vapor, based on which a highly efficient humidity sensor was fabricated. Among different kinds of humidity sensors, the present sensing system stood out due to its fast response rate, good sensitivity and high selectivity with a low detection limit of 0.6 μg mL−1 (S/N = 3) and a wide detection range from 4 to 40 μg mL−1. On the other hand, a majority of the conventional electronic humidity sensors seriously suffered from temperature dependence, while the present sensing system got over this disadvantage. Therefore, the NH2-MIL-53(Al) nanorod layer-based fluorescence sensing system has the potential for application in the real-time monitoring of humidity under ambient conditions.
Xudong Wang,Yanyang Wu,Tianyou Wang,Bin Wu,Kui Chen,Lijun Ji
M-cresol and p-cresol, typically produced as mixtures in industrial processes, are crucial chemical intermediates. However, their separation is challenging due to their similar structures and properties. ZSM-5 zeolite has shown potential as an adsorbent for separation, while the performance is yet to be improved. In this study, ZSM-5-F(x) was synthesized via hydrothermal method, incorporating F − ions during the synthesis process. The adsorption behaviour of m-cresol and p-cresol on ZSM-5-F(x) was investigated through static experiments, with ZSM-5-F(8) demonstrating the highest selectivity (9.01). Both ZSM-5-F(0) and ZSM-5-F(8) were characterized using XRD, scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) techniques. In addition, the introduction of F − ions increased the material's electronegativity, as demonstrated by the change in zeta potential from 53.22 to −45.93 mV. Single-component adsorption of m-cresol or p-cresol on ZSM-5-F(0) and ZSM-5-F(8) respectively were investigated in detail. The adsorption of m-cresol on ZSM-5-F(8) showed a non-monotonic phenomenon with a significant decrease after 0.06 mol/L. The thermodynamic parameters including Δ G , Δ H , and Δ S were calculated accordingly. All the values |Δ G |, |Δ H |, and |Δ S | of both components on ZSM-5-F(8) were greater than those on ZSM-5-F(0), suggesting that the introduction of F − ions facilitated the adsorption. Competitive adsorption experiments on both ZSM-5-F(0) and ZSM-5-F(8) were conducted at 298.2 K. The results indicated that the selectivity α p/m on ZSM-5-F(8) increased with increasing initial concentration and laid between 13 and 14. After seven consecutive regeneration cycles, the selectivity (α p/m ) only decreased to 13. This study suggests that ZSM-5-F(8) could be a promising adsorbent for m-cresol and p-cresol in industrial applications.
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