Adsorption of CO2 on chitosan modified CMK-3 at ambient temperature

Experimental and modelling studies of carbon dioxide capture onto pristine, nitrogen-doped, and activated ordered mesoporous carbons

The search for suitable materials for carbon dioxide capture and storage has attracted the attention of the scientific community in view of the increased global CO₂ levels and its after-effects. Among the different materials under research, porous carbons and their doped analogues are extensively debated for their ability to store carbon dioxide at high pressures. The present paper examined high-pressure carbon dioxide storage studies of 1-D hexagonal and 3-D cubic ordered mesoporous pristine and N-doped carbons prepared using the nano-casting method. Excess carbon dioxide sorption isotherms were obtained using the volumetric technique and were fitted using the Toth model. Various parameters that influence CO₂ storage on metal-free ordered mesoporous carbons, such as the effect of pore size, pore dimension, pyrolysis temperature, the impact of nitrogen substitution, and the effect of ammonia activation are discussed. It was observed that the carbon dioxide storage capacity has an inverse relation to the total nitrogen doped, the amount of pyridinic nitrogen functionality, and the pyrolysis temperature, whereas the pore size seems to have a linear relationship. On the other hand, the presence of oxygen has a positive effect on the sorption capacity. Among the prepared ordered mesoporous carbons, the ammonia-treated one has shown the highest adsorption capacity of 37.8 mmol g^-1 at 34 bar and 0 °C.

Capacitive Desalination and Disinfection of Water Using UiO-66 Metal-Organic Framework/Bamboo Carbon with Chitosan

The zirconium-based metal-organic framework (MOF) (UiO-66)/bamboo carbon (BC) composite with chitosan was prepared using hydrothermal and impregnation methods and used for capacitive desalination (CDI) and disinfection of water. The results showed that these composites had fast ion exchange and charge transfer properties. During the CDI process, these composites' electrodes exhibited good cycle stability, electrosorption capacity (4.25 mg/g) and excellent bactericidal effect. These carbon-based composites electrodes' bactericidal rate for Escherichia coli could reach 99.99% within 20 minutes; therefore, they had good performance and were a good choice for high-performance deionization applications.

Synthesis, Characterization, and CO2 Uptake of Adsorbents Prepared by Hydrothermal Carbonization of Chitosan

Chitosan, a heteropolysaccharide obtained from the N-deacetylation of chitin, has stood out as a raw material to produce CO2 adsorbents. In this work, we report the hydrothermal carbonization (HTC) of chitosan for different times and the potential of the materials for CO2 adsorption. Elemental analysis indicated that the carbon weight content increases, whereas the relative amount of oxygen atoms decreases upon increasing the time of HTC. The relative nitrogen content was almost constant, indicating that HTC did not lead to significant loss of nitrogenated compounds. FTIR and 13C MAS/NMR spectra suggest that the structure of the sorbents becomes more aromatic with the increase of HTC time. The thermal properties of HTC materials were similar to that of chitosan, whereas their basicity was less compared to that of the parent chitosan. SEM images did not show significant porosity, which was confirmed by the BET area of the materials, around 2 m2·g-1, similar to that of the parent chitosan. The materials were tested for CO2 capture at 25 °C and 1 bar; the HTC chitosan adsorbents showed CO2 uptakes about 4-fold higher than that of the parent chitosan. The adsorption process was better described by the Freundlich isotherm and the pseudo-second-order kinetic model.

Three-dimensional cubic ordered mesoporous carbon with chitosan for capacitive deionization disinfection of water

Three-dimensional cubic ordered mesoporous carbon with chitosan (Ia3d-CS), which was synthesized via exothermic reaction between liquid potassium and carbon monoxide gas, was coated on the active carbon (AC) electrode as a capacitive deionization (CDI) disinfection electrode. The results showed that Ia3d-CS-2 as CDI electrode exhibited the quick ion diffusion and strong charge transfer performance, due to the three-dimensional pore structure and specific surface area. The electrode of Ia3d-CS-2 displayed a specific capacity of 191.22 F/g at a scan rate of 100 mV·s^-1 in 0.5 M NaCl aqueous solution. In a CDI recycling system, Ia3d-CS-x electrode showed good cyclic stability, and the electrosorption capacity of Ia3d-CS-2 electrode can achieve 1.31 mg/g at 1.2 V in 100 mg/l NaCl aqueous solutions. Subsequently, Ia3d-CS-2 electrode had an excellent disinfection efficiency of killing about 99.99% Escherichia coli within 30 min during the CDI process at applied 1.2 V. Considering those excellent properties of the fabricated Ia3d-CS-x electrode, which should be a better candidate for high-performance deionization application.

Ordered Mesoporous Carbon with Chitosan for Disinfection of Water via Capacitive Deionization

Capacitive deionization (CDI) with water disinfection materials is a potential method to produce fresh water from aqueous solutions. Therefore, an ordered mesoporous carbon with chitosan (OMC-CS) was coated on the active carbon (AC) electrode as a capacitive deionization disinfection (CDI) electrode. Comparing with OMC-CS-4,6,8 as CDI electrodes, it was found that OMC-CS-6 as a CDI electrode had an excellent disinfection efficiency, killing about 99.99% Escherichia coli (E. coli) in the CDI process at an applied 1.2 V. The OMC-CS material was did not pollute the water and will not contaminate to the environment in comparison with other chemical antibacterial agents. This CDI electrode could play a huge role in biocontaminated water in the future.

Trends in Solid Adsorbent Materials Development for CO2 Capture

A recent report from the United Nations has warned about the excessive CO₂ emissions and the necessity of making efforts to keep the increase in global temperature below 2 °C. Current CO₂ capture technologies are inadequate for reaching that goal, and effective mitigation strategies must be pursued. In this work, we summarize trends in materials development for CO₂ adsorption with focus on recent studies. We put adsorbent materials into four main groups: (I) carbon-based materials, (II) silica/alumina/zeolites, (III) porous crystalline solids, and (IV) metal oxides. Trends in computational investigations along with experimental findings are covered to find promising candidates in light of practical challenges imposed by process economics.