Functionalized metal organic framework (MOF) and covalent organic framework (COF) composites (MOF@COFs) with complementary advantages, hierarchical pores, pre-designable and tunable structures, are expected for remarkable adsorption of organic pollutants, yet to be explored. Herein, a kind of MOF@COF composite was synthesized by combining the parent MIL-68(In) and COF–V (10 %-MIL-68@COF–V), characterized with well-retained crystallinity and hierarchical pores. The parent materials and as-prepared MIL-68@COF-Vs were further fabricated as solid phase microextraction (SPME) coatings to study their extraction performance for Cl/Br-substituted organic pollutants. The 10 %-MIL-68@COF–V coated fiber exhibited the most outstanding enrichment performance for Cl/Br-substituted organic pollutants mainly due to the synthetic advantages, which was 1.1–196.5 times superior than that of the commercial PDMS coating. By combining it with gas chromatography-mass spectrometry (GC-MS), an ultrasensitive method was established, exhibiting wide linear ranges (1–5000 ng L −1 ), low LODs (0.17–0.29 ng L −1 ), and good reproducibility. The trace Cl/Br-substituted organic pollutants in marine water samples were successfully detected, verifying the practicability of the developed method in environmental monitoring.
Pan Yang,Jinlan Tang,Zhuorui Ding,Yiqun Chen,Zizheng Liu,Jianping Yuan,Yuhua Zhu,Pengchao Xie
Carbocatalysts, widely regarded as eco-friendly catalysts in the field of peroxymonosulfate (PMS) activation for pollutant removal, exhibit significant variations in performance depending on the type of carbon atom hybridization. Notably, the novel graphdiyne (GDY), characterized by its sp-hybridized carbon (sp-C), has recently garnered significant attention. However, the precise mechanistic role of sp-C on PMS activation remains unclear. Herein, we elucidate the role of sp-C on PMS activation and the corresponding mechanism behind enhanced phenolic pollutant degradation over the GDY catalyst. GDY demonstrates exceptional phenolic removal efficiency (97 %), which far exceeds that of traditional sp 2 -hybridized graphene (2 %). The GDY facilitates pollutant oxidation via a catalyst-mediated electron transfer mechanism. The sp-C provides additional sites for PMS adsorption and donates significantly more electrons from GDY to PMS (0.51 e more than graphene), effectively facilitating PMS activation, intermediate species conversion, and reaction kinetics during phenolic pollutant degradation. By integrating the monolithic GDY catalyst into a flow-through device for continuous phenolic pollutant removal, long-lasting phenolic removal was maintained for over 80 hours, with a removal rate exceeding 85 %. This work highlights that sp-C in GDY effectively enhances PMS activation, providing a pathway for efficient organic pollutant degradation in advanced oxidation processes.
Improving the zeolite adsorption separation efficiency of individual xylene isomer with high purity from their mixture is still a pressing challenge in the fine chemical industry. Herein, plate-like silicalite-1 (p-S-1) zeolite crystals with short b-axis thickness have been successfully synthesized by combination of tributylphosphine oxide (TBPO) modifier and F − -assisted crystallization method to first investigate the separation property of xylene isomers. The morphology and structure of the p-S-1 zeolite crystals were characterized by XRD, FTIR, BET, SEM and TEM. The results showed that the p-S-1 zeolite crystals with thickness of about 50 nm along the b-axis and high crystallinity, as well as extremely rich micropores, were obtained by crystallizing the gels with TBPO/SiO 2 ≥ 0.04. By static adsorption experiment and fixed bed experiment, xylene isomers selective adsorption separation property of the p-S-1 zeolite crystals prepared at TBPO/SiO 2 = 0.04 was investigated. The static adsorption experiment demonstrated that the p-S-1 zeolite crystals exhibited higher adsorption capacity of p-xylene (p-X) and more excellent xylene isomers separation performance than that of the bulk coffin-shaped silicalite-1 (c-S-1) zeolite crystals because of the shorter mass transfer channel and larger diffusivity differences between p-X and o-X/m-X/EB. The dynamic adsorption experiment in simulated five-component solutions diluted by isooctane (IO) indicated that the p-S-1 zeolite crystals had excellent xylene isomers selective adsorption separation performance. The optimum dynamic xylene isomers selective adsorption separation factors for p-X/o-X, p-X/m-X and p-X/EB were 25.41, 36.45 and 11.57 at 150 °C, respectively. The regeneration experiment also indicated that the p-S-1 zeolite crystals had more stable structure and longer lifetime. This work suggested that the p-S-1 zeolite crystals had great potential as new adsorbent for selective adsorption separation of xylene isomers.
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