Impact on CO₂ Uptake of MWCNT after Acid Treatment Study

Abstract

Greenhouse effect is responsible for keeping average temperature of Earth's atmosphere at level of about 288 K. Its intensification leads to warming of our planet and may contribute to adverse changes in the environment. The most important pollution intensifying greenhouse effect is anthropogenic carbon dioxide. This particular gas absorbs secondary infrared radiation, which in the end leads to an increase of average temperature of Earth's atmosphere. Main source of CO 2 is burning of fossil fuels, like oil, natural gas, and coal. Therefore, to reduce its emission, a special CO 2 capture and storage technology is required. Carbonaceous materials are promising materials for CO 2 sorbents. Thus multiwalled carbon nanotubes, due to the lack of impurities like ash in activated carbons, were chosen as a model material for investigation of acid treatment impact on CO 2 uptake. Remarkable 43% enhancement of CO 2 sorption capacity was achieved at 273 K and relative pressure of 0.95. Samples were also thoroughly characterized in terms of texture (specific surface area measurement, transmission electron microscope) and chemical composition (X-ray photoelectron spectroscopy).

Antibiofilm Effect of Nitric Acid-Functionalized Carbon Nanotube-Based Surfaces against E. coli and S. aureus

“…Contrary to that observed for S BET , chemical functionalization with nitric acid resulted in a decrease in the V p from 0.419 to 0.408 cm 3 g −1 for p-MWCNT and f-MWCNT_N samples, respectively. This decrease in the V p is in accordance with the literature on nitric acid-treated MWCNT samples [38,39,41,44] and may be related to the different extent of CNT agglomeration, which is typical of samples with different surface chemistries [40,45]. In turn, the heat treatment at 600 • C resulted in an increase in V p (from 0.408 to 0.432 cm 3 g −1 , when f-MWCNT_N and f-MWCNT_N600 are compared), which is in agreement with previously published results [40].…”

“…Although no relevant changes were observed in the S BET values, an increase in the surface area of oxidized MWCNT samples compared to p-MWCNTs was obtained. According to previous studies, this increase can be explained by the opening of MWCNT end caps and the creation of sidewall openings, which are structural defects that increase the available area for N 2 adsorption [37,40,43,44]. With the thermal treatment at 600 • C, part of the chemical groups introduced during oxidation treatment with HNO 3 were removed, leading to a slight increase in the specific surface area [37].…”

The Effect of the Modification of Carbon Spheres with ZnCl2 on the Adsorption Properties towards CO2

“…Activated carbon derived from biomasses, e.g., rice husk [34] or wheat flour [35], exhibit a CO 2 uptake equal to 6.24 and 5.70 mmol/g, respectively, at 0 • C and 1 bar. Acid-treated multiwalled carbon nanotubes expressed CO 2 uptake at 2.53 mmol/g at 0 • C and 1 bar [36]. Another promising group of carbon materials for CO 2 adsorption are carbon fibers.…”

CO2 Adsorption on Activated Carbons Prepared from Molasses: A Comparison of Two and Three Parametric Models

“…Therefore, many researchers are focused on developing technologies, leading to the capture and storage of carbon dioxide, especially adsorption techniques, which are currently considered very promising [ 2 ]. Recently, many solid adsorbents have been reported, which could be applied in the CO 2 capture: activated carbons [ 3 , 4 ], zeolites [ 5 ], metalloorganic structures [ 6 ], porous polymers [ 7 ], carbon nanosheets [ 8 ], metal oxides [ 9 ], TiO 2 modified by nitrogen [ 10 ], activated carbons-TiO 2 composites [ 11 ], TiO 2 modified by amines [ 12 ], TiO 2 /titanate composite nanorods [ 13 ], TEPA-modified titanate composite nanorods [ 14 ], carbon nanotubes [ 15 ], monoliths [ 16 ]. Among the above-mentioned materials, the carbonaceous materials are considered as particularly promising with regard to a low production cost, well developed porosity, large surface area, readily controlled structure, good thermal and chemical stability and large efficiency as well as the wide spectrum of usage [ 17 , 18 ].…”

“…The isotherm is used to characterize and evaluate the most important properties of adsorbent such as adsorbent affinity, adsorption capacity, adsorption mechanism and quantitative distribution of adsorbate on adsorbent and bulk solution. The adsorption process is described by isotherm models of two, three, four, and even five parameters [ 15 , 19 , 20 ]. To determine adsorption isotherm and its constant, experimental and calculation stages are required.…”