The chitosan (CS)-grafted UiO-66-NH 2 (U6N) (CSGUN) was synthesized and incorporated into Pebax matrix to fabricate mixed matrix membranes (MMMs) for boosting CO 2 transport. The excellent CO 2 separation performance was exhibited for MMMs due to the following reasons: U6N with the suitable porosity and abundant CO 2 transport carriers can provide a unique “expressway” for CO 2 to boost CO 2 transport through MMMs. The grafting CS in CSGUN can connect Pebax (regular roads) and U6N (expressway), acting as an “on-ramp” between them to enrich CO 2 and guide CO 2 through U6N in an orderly manner. Thus, the constructed “on-ramp” and “expressway” in MMMs can improve CO 2 separation performance. Furthermore, the CS-MOF networks were formed in MMMs through using CS molecular chains to connect U6N for enhancing CO 2 separation performance of MMMs. Therefore, Pebax/CSGUN MMMs exhibited the excellent CO 2 separation performance with the CO 2 permeability of 558 ± 7 Barrer and the CO 2 /CH 4 selectivity of 37.5 ± 0.7. The study indicated that MMMs with CS-MOF bridged networks had great potential for boosting CO 2 transport by combining “expressways” and “on-ramp”.
Yang Yang,Mengting Zhu,Yijia Jin,Hui Cai,Yiran Huang,Yingling Wan,Yan Liu
Paeonia lactiflora is an important garden ornamental flower and has become a new cut flower in the international market in recent years. Stem mechanical strength is an important index of cut flower quality. P. lactiflora cultivars possess varying stem mechanical strength, which directly result in different cut P. lactiflora quality. In our previous study, a significant difference in phloem callose deposition was detected between two P. lactiflora cultivars with varying stem mechanical strength. However, the relationship and interaction mechanism between the phloem callose and mechanical strength in P. lactiflora stems are still unclear. This study aimed to analyze the effects of reduced phloem callose on the mechanical strength in P. lactiflora stems. The results revealed a negative correlation between the callose content and mechanical strength in P. lactiflora stems during early developmental stages. Exogenous 2DDG treatment led to a 13.6% reduction in the callose content, concomitantly enhancing the stem mechanical strength by 14.2% via facilitating the formation and secondary cell wall (SCW) thickening of xylem fiber cells. Further investigations showed that exogenous 2DDG treatment promoted carbon transport in P. lactiflora stems, thereby increasing the carbon content. Additionally, it induced alterations in the metabolism of lipids, amino acids, and organic acids in the stems and spurred the diffusion of lipids from the pith to the xylem. Consequently, reducing the content of callose improved the formation and SCW thickening of xylem fiber cells by modifying material transport and metabolism, thereby enhancing the stem mechanical strength of P. lactiflora . This study offers novel perspectives regarding the regulatory mechanism of P. lactiflora stem mechanical strength.
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