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A 3D monolithic Ti 3 C 2 T x /RGO hybrid hydrogel has been fabricated by a room-temperature GO-assisted gelation method with l -cysteine and Na 2 S, which exhibited excellent performances as self-standing anode for electrochemical sodium-ion storage. [Display omitted] • 3D Ti 3 C 2 T x MXene/RGO hydrogels have been successfully fabricated at room temperature by introducing Na 2 S as the primary reducing agent and l -cysteine as the auxiliary crosslinker. • This room-temperature gelation method not only effectively inhibits the restacking problem of MXene, but also simultaneously avoids the oxidation issue of MXene. • The resulting aerogels with excellent structural robustness can be used as the self-standing electrode, which delivered remarkable specific capacity and excellent cycling stability for sodium-ion storage. Assembling two-dimensional (2D) MXene nanosheets into monolithic three-dimensional (3D) structures is an efficient pathway to transfer the nanoscale properties to practical applications. Nevertheless, the majority of the preparation schemes described in the literature are carried out at relatively high temperatures, which inevitably leads to the notorious high-temperature oxidation issue of MXenes. Preparing MXene-based hydrogels at lower temperatures or even room temperature is of great research importance. In this study, we report a novel and efficient room-temperature gelation method for fabricating 3D macro-porous Ti 3 C 2 T x MXene/reduced graphene oxide (RGO) hybrid hydrogels, using anhydrous sodium sulfide (Na 2 S) as the primary reducing agent and l -cysteine as the auxiliary crosslinker. This room-temperature preparation technique successfully prevents the oxidation issue of MXenes and generates porous aerogels with excellent structural robustness after freeze-drying. As the self-standing anode for sodium-ion storage, the optimized 3D Ti 3 C 2 T x MXene/RGO electrode possesses a specific capacity of 152 mAh/g at 0.1 A/g and good cycling stability with no significant capacity degradation after 500 cycles, which is significantly higher than that of the vacuum-filtered MXene film. This work demonstrates a straightforward room-temperature gelation method for constructing 3D MXene-based hydrogels to avoid the oxidation of MXenes, and casts new insight on the mechanism of the graphene oxide (GO)-assisted gelation. [ABSTRACT FROM AUTHOR]

The graphical abstract of sEVs capture and release by the constructed ISM-NPs. [Display omitted] Enriching small extracellular vesicles (sEVs) with undamaged structure and function is a pivotal step for further applications in biological and clinical fields. It has prompted researchers to explore a carrier material that can efficiently capture sEVs while also gently release the captured sEVs. Here, 1-adamantylamine (1-ADA) responsive immuno-affinitive supramolecular magnetic nanoparticles (ISM-NPs) incorporating ternary host-guest complexation structures mediated by CB[8] were proposed to achieved the goal. In particular, the ternary host-guest complexation was constructed by the host molecule (cucurbit[8]uril, CB[8]) mediated assembly of two guest molecules (naphthol and bipyridine), and served as a cleavable bridge to connect the magnetic core and peripheral antibody. These constructed ISM-NPs performed well in the applications of capturing sEVs with a high capture efficiency of 85.5%. Further, the CB[8]-mediated ternary host-guest complexation structures can be disassembled with addition of the 1-ADA. Thus, the sEVs recognized by the anti-CD63 were released competitively, with a decent release efficiency more than 82%. The released sEVs kept intact morphology and exhibited appropriate size distribution and concentration. This supramolecular magnetic system, with 1-ADA responsive ternary host-guest complexation structures, may contribute to efficient enrichment of any other biomarkers, likely cells, proteins, peptides, etc. [ABSTRACT FROM AUTHOR]

In recent years, there have been a number of studies on bioretention during hot summer, with only few studies reported during low-temperature winters. The application of bioretention in cold areas still lacks effective guidance. In this study, runoff simulation experiments were conducted to explore the influence of wood chips filler and water treatment residue on the removal of runoff pollutants under different packing gradations and low temperature conditions. Under low temperature, nitrate nitrogen removal rate of wood chips filler decreased from 70% to 90% in autumn to −23%- 35% in winter, the total nitrogen removal rate decreased from 75 to 90% in autumn to 20%–50% in winter, the removal rate of ammonia nitrogen and total phosphorus exceeded 70% during the entire experiment. Water treatment residue filler maintained a high ammonia nitrogen and total phosphorus removal rate during the experiment, with the total phosphorus removal rate above 90% and ammonia nitrogen removal rate above 80%. The bioretention effluent concentration of nitrate and total nitrogen was higher than 7.3 mg/L and 8.5 mg/L, respectively, most of the time. However, at low temperature, the COD removal rate of the two fillers was 25%–50%, which was very poor. Therefore, wood chips filler was observed to be better suited for the removal of nitrate and total nitrogen from the runoff, while water treatment residue had a better effect on the removal of ammonia nitrogen and total phosphorus in winter. Thus, for the application of bioretention in northern China, appropriate fillers should be selected considering the water quality characteristics of the area. [Display omitted] • The removal rate of NH 4 +-N and TP remained high at low temperature. • In winter the solid carbon can't enhance the removal of NO 3 −-N and TN. • The effect of packing gradation on water purification is not obvious. • At low temperature, bioretention could not effectively remove COD. [ABSTRACT FROM AUTHOR]