An environmentally friendly and low-cost chitosan-containing polysaccharide (CP) composite ZIF-8/CP was designed and prepared based on the difficulty of separating the traditional adsorbent from the water phase. ZIF-8/CP was synthesized through in-situ growth approach. The physical, chemical and structure properties of ZIF-8/CP were determined through a series of characterization methods, including SEM, FT-IR and PXRD. The effects of touch time, pH, temperature, and coexisting ions on adsorption were assessed. In addition, kinetics, isotherms of adsorption and thermodynamics were examined. The data of isotherms for adsorption indicated that the adsorption of ZIF-8/CP on MG was similar to the Langmuir model, with a maximum adsorption capacity of 1428.57 mg/g. Moreover, the kinetic parameters were consistent with the pseudo- 2nd-order equation. Thermodynamic studies (ΔG < 0, ΔH > 0) demonstrated a heat-absorbing and spontaneous adsorption process. Our study reveals that ZIF-8/CP has good adsorption properties and environmental properties.

Nitrogen-doped carbons have attracted much attention due to their novel application in relation to gas storage. In this study, nitrogen-doped porous carbons were synthesized using SBA-15 as a template, polypyrrole as the carbon and nitrogen precursor, and KOH as an activating agent. The effect of the activation temperature (600–850°C) on the CO2 adsorption capacity of the obtained porous carbons was studied. Characterization of the resulting carbons showed that they were micro-/meso-porous carbon materials with a well-developed pore structure that varied with the activation temperature. The highest surface area of 1488 m2 g–1 was achieved at an activation temperature of 800°C (AC-800). The nitrogen content of the activated carbon decreased from 4.74 to 1.39 wt% with an increase in the activation temperature from 600 to 850°C. This shows that nitrogen is oxidized and more easily removed than carbon during the activation process, which indicates that C-N bonds are more easily ruptured at higher temperatures. Furthermore, CO2 adsorption isotherms showed that AC-800 exhibited the best CO2 adsorption capacity of 110 mg g–1 at 298 K and 1 bar.

Porous carbons have attracted much attention for their novel application in gas storage. In this study, porous graphite nano-fiber (PGNFs)-based graphite nano fibers (GNFs) were prepared by KOH activation to act as adsorbents. The GNFs were activated with KOH by changing the GNF/KOH weight ratio from 0 through 5 at 900°C. The effects of the GNF/ KOH weight ratios on the pore structures were also addressed with scanning electron microscope and N2 adsorption/desorption measurements. We found that the activated GNFs exhibited a gradual increase of CO2 adsorption capacity at CK-3 and then decreased to CK-5, as determined by CO2 adsorption isotherms. CK-3 had the narrowest micropore size distribution (0.6–0.78 nm) among the treated GNFs. Therefore, KOH activation was not only a significant method for developing a suitable pore-size distribution for gas adsorption, but also increased CO2 adsorption capacity as well. The study indicated that the sample prepared with a weight ratio of ‘3’ showed the best CO2 adsorption capacity (70.8 mg/g) as determined by CO2 adsorption isotherms at 298 K and 1 bar.

Recently, with continuous developments in the field of materials science, graphene oxide (GO) has emerged as a promising material with excellent electrical, thermal, mechanical, and optical properties, which play important roles in most fields. Researchers have achieved considerable progress with graphene. Chitosan (CS) is a natural polymer that has been studied intensively owing to its specific formation, high chemical resistance, and excellent physical properties. These outstanding properties have led to its universal use in applications such as textile fabrics, tissue engineering, medicine and health, coatings, and paints. By combining the advantages of GO and CS, different types of promising materials can be obtained. This review discusses the preparation of GO-CS fibers, hydrogel and aerogel, and the applications of GO-CS nanocomposites. In addition, directions for future research on graphene material composites are discussed.