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The zeolitic imidazolate framework ZIF-69 with topology of GME has been synthesized successfully via a facile hydrothermal synthetic method, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption-desorption measurements, thermal gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The ethane/ethylene separation potential was measured by single-component adsorption isotherms, and the selectivity was calculated based on the ideal adsorbed solution theory (IAST). SEM and TEM images confirmed that the as-synthesized seeds possessed a well-crystallized and uniform morphology, appearing as a flat hexagonal prism with double hexagonal pyramid heads. The obtained ZIF-69 exhibited a higher adsorption capacity of C 2 H 6 over C 2 H 4 at 100 kPa, and the C 2 H 6 /C 2 H 4 adsorption selectivity was about 1.7 at below 100 kPa. The outcome would provide a new insight into the study on the effective separation of ethane/ethylene using different topological structures of ZIFs. [ABSTRACT FROM AUTHOR]

This paper presents low-cost and recyclable activated carbon (XLAC) derived from Xanthoceras sorbifolia Bunge hull for high-efficiency adsorption of Cd(II) and Hg(II) ions in industrial wastewater. XLAC was prepared through H3PO4 activation and was characterized using N2 adsorption-desorption, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDX), and Fourier transform infrared (FTIR) spectroscopy. In single-metal-system adsorption experiments, the maximum adsorption capacities for Cd(II) and Hg(II) obtained under different experimental conditions were 388.7 and 235.6 mg·g−1, respectively. All adsorption equilibrium data fit perfectly with the Langmuir isotherm model. In a binary metal system, competitive studies demonstrated that the presence of Cd(II) significantly decreased the adsorption of Hg(II), but the adsorption of Cd(II) showed a little change in the presence of Hg(II). In addition, XLAC can be regenerated with a 0.01 mol·L−1 HNO3 solution and reused at least four times. The FTIR spectra revealed that a chemical interaction occurs between functional groups containing lone electron pairs in XLAC and metal ions. Overall, these results suggest that XLAC may be suitable as an adsorbent for heavy metal removal from wastewater streams. [ABSTRACT FROM AUTHOR]

A new and inexpensive lignocellulose/montmorillonite (LNC/MMT) nanocomposite was prepared by a chemical intercalation of LNC into MMT and was subsequently investigated as an adsorbent in batch systems for the adsorption-desorption of Ni(II) ions in an aqueous solution. The optimum conditions for the Ni(II) ion adsorption capacity of the LNC/MMT nanocomposite were studied in detail by varying parameters such as the initial Ni(II) concentration, the solution pH value, the adsorption temperature and time. The results indicated that the maximum adsorption capacity of Ni(II) reached 94.86 mg/g at an initial Ni(II) concentration of 0.0032 mol/L, a solution pH of 6.8, an adsorption temperature of 70°C, and adsorption time of 40 min. The represented adsorption kinetics model exhibited good agreement between the experimental data and the pseudo-second-order kinetic model. The Langmuir isotherm equation best fit the experimental data. The structure of the LNC/MMT nanocomposite was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), whereas the adsorption mechanism was discussed in combination with the results obtained from scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy analyses (FTIR). The desorption capacity of the LNC/MMT nanocomposite depended on parameters such as HNO3 concentration, desorption temperature, and desorption time. The satisfactory desorption capacity of 81.34 mg/g was obtained at a HNO3 concentration, desorption temperature, and desorption time of 0.2 mol/L, 60 ºC, and 30 min, respectively. The regeneration studies showed that the adsorption capacity of the LNC/MMT nanocomposite was consistent for five cycles without any appreciable loss in the batch process and confirmed that the LNC/MMT nanocomposite was reusable. The overall study revealed that the LNC/MMT nanocomposite functioned as an effective adsorbent in the detoxification of Ni(II)-contaminated wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • Using a non-toxic process to prepare biomass blue light emitting carbon quantum dots. • A new fluorescence cellulose hydrogel material with NCDs as core was synthesized. • The blue light emission of the fluorescence cellulose hydrogel can be applied to detect and absorb of heavy metal ions. • Providing an idea for construction of new hydrogel materials. To combat the contaminating effects of heavy-metal ions on water resources, we prepared blue photonitrogen-doped carbon quantum dots (NCDs) from Salix psammophila (SP) as a raw material, doped them into a microcrystalline cellulose hydrogel, and successfully created a composite hydrogel (NCDs-SP-MCC-gels) for concurrent fluorescence detection and Fe3+ adsorption. The NCDs-SP-MCC-gels was examined for their shape, chemical composition, fluorescence characteristics, and adsorption behaviors. Results demonstrated that the NCDs-SP-MCC-gels displayed a broad linear range of Fe3+ fluorescence response (200–1000 mg/L; detection limit = 3.90583 mg/L) and a high adsorption capacity for Fe3+ (610 mg/g). The adsorption data fitted the Langmuir and pseudo-second-order models well. Further research was conducted on Fe3+ detection and adsorption onto the NCDs-SP-MCC-gels. This study proposes a green and sustainable way to create a material for the detection and absorption of heavy-metal ions. [ABSTRACT FROM AUTHOR]