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UiO‐66‐NH2/black phosphorus quantum dots (MOF/BPQDs) heterojunctions are anchored on the carboxyl cellulose nanofiber (CNF) aerogel with high porosity (>98%) to fabricate high‐efficiency uranium adsorbents (BP@CNF‐MOF). CNF aerogels possess abundant carboxyl groups, which can serve as nucleation centers to in situ synthesize UiO‐66‐NH2 with smaller crystal size, high mass loading, and good adhesion. BP@CNF‐MOF demonstrates good mechanical flexibility and minimal MOF loss from the CNF aerogel, both of which result from the mutual physical interactions and entanglements of CNFs as well as strong binding interactions between MOF crystals and CNF aerogel. Owing to the excellent heterogeneous photocatalytic activity of MOF/BPQDs, on one hand, marine bacteria can be effectively destroyed by reactive oxygen species (ROS). On the other hand, the photocatalytic U(VI) reduction to insoluble U(IV) could be facilitated, thereby allowing more binding sites on the MOF crystals for further U(VI) adsorption. Consequently, compared with dark conditions, the adsorption efficiency of the light irradiated BP@CNF‐MOF increases by 55.3%, reaching up to 6.77 mg‐U per g‐Ads after 6 weeks of exposure to natural seawater. The intrinsic instability of BPQDs can be overcome by MOF coating layer simultaneously. The strategy applied in this work could also be applicable to other superior MOF crystals. [ABSTRACT FROM AUTHOR]

Abstract A triazine-based MOFs [PCN-9(Co)] was synthesized and its photoelectrical, photophysical properties were studied. As a new photocatalyst, PCN-9(Co) displays photocatalytic hydrogen evolution from water under UV–Visible light irradiation. With the introduction of platinum complex, PCN-9-Pt was obtained and platinum complex was believed to coordinate with the N in triazine. The H 2 evolution rate of PCN-9-Pt is greatly improved, about 6.8 times higher than that of PCN-9(Co). The reason is due to the fact that platinum complex plays an important role in improving the separation efficiency of photogenerated charge carriers, as verified by PL and EIS results. This result provides a new kind of idea of modifying MOFs materials with molecular complex to improve the photocatalytic activity. Graphical abstract Proposed photocatalytic mechanism of PCN-9-Pt. fx1 Highlights • Triazine-based MOFs [PCN-9(Co)] could be used as a new photocatalyst for hydrogen evolution. • Introduced platinum ions coordinate with the N in triazine which improve H 2 evolution rate greatly. • Platinum complex plays an important role in improving the separation efficiency of photogenerated charge carriers. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Effective and selective removal of Pb(II) from aqueous solution is highly desirable, but it is still a great challenge. We report here a water stable metal-organic frameworks (CAU-7-TATB), and the ligands contain N, which provides binding sites for metal ions. CAU-7-TATB exhibits fast adsorption kinetics, high adsorption capacity towards Pb(II). More importantly, CAU-7-TATB remains high prior adsorption towards Pb(II) in the presence of interfering ions like Cr(III), Co(II), Ni(II), Mn(II), Zn(II), Mg(II) and Ca(II), which is potentially applicable in removing Pb(II) from industrial water. [ABSTRACT FROM AUTHOR]

[Display omitted] • The incorporation of TCPP(Ni) enhances the visible light absorption of UIO-type MOF. • TCPP(Ni) ligands give rise to the downward LUMO energy level of Zr-oxo cluster. • More mesoporous created by TCPP(Ni) increase utilization of hidden binding sites. • A high U-sorption capacity of 8.95 mg-U/g-Ads is achieved from natural seawater. Integrating multi-functionality into metal–organic frameworks (MOFs) has attracted growing attention as it plays a critical role in realizing the potential of MOFs for a wide variety of applications. Owing to the ultrahigh surface areas and porosity, MOFs have been recognized as potential adsorbents for uranium capture through chemical chelation of uranyl ions (UO 2 2+). As a new type of photocatalyst, however, these MOFs are rarely applied in uranium recovery by photocatalytic reduction of soluble U(VI) to the less soluble U(IV), which is largely due to the limited visible light harvesting as well as the poor separation and transfer of photo-generated carriers. Herein, we present a facile one pot synthetic route to incorporate photo-responsive Ni(II)-centered porphyrin (TCPP(Ni)) ligands into UIO-66-NH 2 (TCPP(Ni) ⊂ MOF) while maintaining the crystal structure and ultrahigh chemical stability. TCPP(Ni) not only provides strong visible light harvesting but also improves the charge transfer from excited ligands to Zr-oxo clusters. Consequently, the mixed-linker strategy boosts the photoreduction of soluble U(VI) to the less soluble U(IV) for uranium immobilization. After optimization, TCPP(Ni) ⊂ MOF-3 presents excellent selective uranium capture from wastewater and natural seawater through combined complexation and photoreduction. Strikingly, after immersing in natural seawater for 25 days, a high uranium sorption capacity of 8.95 ± 0.39 mg-U/g-Ads can be achieved together with good antibacterial ability. This work provides a promising strategy to improve the photoreduction potential of MOF adsorbents for uranium capture. [ABSTRACT FROM AUTHOR]

[Display omitted] • MOF-bonded carbon sponge is designed for photothermally enhancing U(VI) adsorption. • The mass loading of UiO-66-NH 2 prepared by in-situ growth can reach up to 85 wt%. • The monolithic MOF adsorbent exhibits favorable elastic and recyclable performance. • The selectivity of U(VI) can be improved when exposure to light irradiation. • Light irradiation yields a 32.37% increase in the U(VI) adsorption amount than dark. Extraction of radioactive uranium from the natural seawater is regarded as one of the most promising ways to address the shortage of uranium resources. As a kind of potential uranium adsorbent, more attention has been paid to metal–organic framework materials (MOFs) due to large specific surface area and high ion selectivity. Currently, however, MOF adsorbents are hardly applied to the real seawater in view of the relatively low uranium adsorption capacity and recyclable issues. Herein, we present the monolithic MOF adsorbent with photothermally enhancing uranium adsorption capacity. Carbon sponge (CS) substrate with macroporous open cell structure was used as excellent photothermal conversion material. Zr-MOF (UiO-66-NH 2) crystals were in situ grown on the fibrils network of polydopamine (PDA) pre-coated CS to obtain UiO-66-NH 2 @CS-PDA adsorbent. It is found that UiO-66-NH 2 coating with perfect coverage and good adhesion has a high mass loading (>85 wt%). As a result, UiO-66-NH 2 @CS-PDA adsorbents exhibited the advantage of high-selectivity, high-affinity and cycling stability. Compared with the dark condition, the uranium adsorption amount was increased by 32.37% after 4 weeks in the natural seawater under simulated solar irradiation, which was mainly ascribed to the endothermic behavior of uranium adsorption process. Moreover, the elasticity attribute of CS was essential for sustenance of volume variation buffering during seawater flow. As a recyclable and favorable elastic large-scale monolithic MOF adsorbent, UiO-66-NH 2 @CS-PDA holds great promise for extracting uranium from the natural seawater. [ABSTRACT FROM AUTHOR]