In this study, one well-known CHM residue (Atropa belladonna L., ABL) was used to prepare biochar capable of adsorbing rhodamine B (RhB) with an ultrahigh surface area for the first time. Three micropore-rich ABL biochars including ABL@ ZnCl 2 (1866 m 2 /g), ABL@H 3 PO 4 (1488 m 2 /g), and ABL@KOH (590 m 2 /g) were obtained using the one-step carbonization method with activation agents (ZnCl 2 , H 3 PO 4 , and KOH) via chemical activation and carbonization at 500 °C, and their adsorption performance for RhB was systematically studied with adsorption kinetics, isotherms, and thermodynamics. Through pore diffusion, π−π interaction, and hydrogen bonding, ABL biochar had excellent adsorption performance for RhB. Moreover, when C 0 was 200 mg/L, biochar dosage was 1 g/L, and the contact time was 120 min; the maximum RhB adsorption capacity and removal efficiency on ABL@ZnCl 2 and ABL@H 3 PO 4 were 190.63 mg/g, 95% and 184.70 mg/g, 92%, respectively, indicating that it was feasible to prepare biochar from the ABL residue for RhB adsorption. The theoretical maximum adsorption capacities of ABL@ZnCl 2 and ABL@H 3 PO 4 for RhB were 263.19 mg/g and 309.11 mg/g at 25 °C, respectively. Furthermore, the prepared biochar showed good economic applicability, with pay back of USD 972/t (ABL@ZnCl 2 ) and USD 987/t (ABL@H 3 PO 4 ), respectively. More importantly, even after five cycles, ABL@H 3 PO 4 biochar still showed great RhB removal efficiency, suggesting that it had a good application prospect and provided a new method for the resource utilization of traditional CHM residues. Additionally, pore diffusion, π−π interactions, and hydrogen bonding all play roles in the physical adsorption of RhB on ABL biochar. π−π interactions dominated in the early stage of RhB adsorption on ABL@H 3 PO 4 , while pore diffusion played a crucial role in the whole adsorption process on both adsorbents.

The ZIF-8 crystals were successfully postsynthetically modified using methylamine (MA), ethylenediamine (ED), and N, N ′ -dimethylethylenediamine (MMEN) to improve their adsorption performance toward CO2. Results showed that, compared with the original ZIF-8, the BET specific surface area of MA-ZIF-8, MMEN-ZIF-8, and ED-ZIF-8 has increased by 118.2%, 92.0%, and 29.8%, respectively. In addition, their total pore volume increased separately by 130.8%, 100%, and 48.7%. The adsorption capacities of CO2 on the amine-modified ZIF-8 samples followed the order MA − ZIF − 8 > MMEN − ZIF − 8 > ED − ZIF − 8 > ZIF − 8 . The CO2 adsorption capacities at 298 K on MA-ZIF-8, MMEN-ZIF-8, and ED-ZIF-8 were increased by 118.2%, 90.2%, and 29.8%, respectively. What is more, the CO2/N2 selectivities calculated using an IAST model of the amine@ZIF-8 samples at 0.01 bar and 298 K were also significantly improved and followed the order MA − ZIF − 8   31.4 > ED − ZIF − 8   25.1 > MMEN − ZIF − 8   14.1 > ZIF − 8   11.5 , which increased by 173.0%, 121.4%, and 22.6%, respectively. The isosteric heat of CO2 adsorption ( Q st ) on the MA-ZIF-8, MMEN-ZIF-8, and ED-ZIF-8 all becomes higher, while Q st of N2 on these samples was slightly lower in comparison with that on the ZIF-8. Furthermore, after six recycle runs of gravimetric CO2 adsorption-desorption on MA-ZIF-8, the adsorption performance of CO2 is still very good, indicating that the MA-ZIF-8 sample has good regeneration performance and can be applied into industrial CO2 adsorption and separation.

The development of probes with sensitive and prompt detection of volatile organic compounds (VOCs) is of great importance for protecting human health and public security. Herein, we successfully prepared a series of bimetallic lanthanide metal–organic framework (Eu/Zr-UiO-66) by incorporating Eu3+ for fluorescence sensing of VOCs (especially styrene and cyclohexanone) using a one-pot method. Based on the multiple fluorescence signal responses of Eu/Zr-UiO-66 toward styrene and cyclohexanone, a ratiometric fluorescence probe using (I 617/I 320) and (I 617/I 330) as output signals was developed to recognize styrene and cyclohexanone, respectively. Benefitting from the multiple fluorescence response, the limits of detection (LODs) of Eu/Zr–UiO-66 (1:9) for styrene and cyclohexanone were 1.5 and 2.5 ppm, respectively. These are among the lowest reported levels for MOF-based sensors, and this is the first known material for fluorescence sensing of cyclohexanone. Fluorescence quenching by styrene was mainly owing to the large electronegativity of styrene and fluorescence resonance energy transfer (FRET). However, FRET was accounted for fluorescence quenching by cyclohexanone. Moreover, Eu/Zr–UiO-66 (1:9) exhibited good anti-interference ability and recycling performance for styrene and cyclohexanone. More importantly, the visual recognition of styrene and EB vapor can be directly realized with the naked eyes using Eu/Zr–UiO-66 (1:9) test strips. This strategy provides a sensitive, selective, and reliable method for the visual sensing of styrene and cyclohexanone.