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Adsorption process is considered to be the most promising alternative for the CO2 capture to the traditional energy-intensive amine absorption process, and the development of feasible and efficient CO2 adsorbents is still a challenge. In this work, the NiO@USY (ultrastable Y) composites with different NiO loadings were prepared for the CO2 adsorption using Ni(NO3)2 as the precursor. The composites were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, nitrogen adsorption–desorption test, scanning electron microscopy analysis, and thermogravimetric analysis, and were evaluated for the CO2 adsorption capacity, CO2/N2 adsorption selectivity and CO2 cycle adsorption capacity. The characterization results show that after the activation at 423 K, the Ni(NO3)2 species were well dispersed into the surface of zeolite USY, and after the further activation at 823 K, Ni(NO3)2 could be converted into highly dispersed NiO. The adsorption results show that the presence of the active component NiO plays an important role in improving the CO2 adsorption performance, and the NiO@USY composite with a NiO loading of 1.5 mmol·g−1 USY support displays a high adsorption capacity and adsorption selectivity for CO2, and shows a good cycle stability. In addition, the Clausius–Clapeyron equation was used to evaluate the isosteric heat of adsorption of CO2 on the NiO(1.5)@USY composite, and the heat of adsorption was 17.39–38.34 kJ·mol−1.

Cinnamon essential oil with many bioactivities is an important raw material for the production of various chemicals, and the conventional hydrodistillation (HD) for cinnamon oil extraction always require a longer extraction time. In this work, ultrasound-assisted hydrodistillation extraction (UAHDE) technique was employed to enhance the extraction efficiency of essential oils from cinnamon barks. The parameters with significant effects on the essential oil extraction efficiency (ultrasound time, ultrasound power, extraction time, liquid–solid ratio) were optimized, and the proposed UAHDE was compared with the conventional HD extraction in terms of the extraction time, extraction yield, and physicochemical properties of extracted oils. Compared to the HD extraction, the UAHDE resulted in a shorter extraction time and a higher extraction yield. Using GC–MS analysis, the UAHDE provided more valuable essential oil with a high content of the vital trans-cinnamaldehyde compounds compared with the HD. Scanning electron micrograph (SEM) confirmed the efficiency of ultrasound irradiation for cinnamon oil extraction. In addition, the analysis of electric consumption and CO2 emission shows that the UAHDE process is a more economic and environment-friendly approach. Thus, UAHDE is an efficient and green technology for the cinnamon essential oil extraction, which could improve the quantity and quality of cinnamon oils.

Copper oxide modified activated carbon (CuO/AC) composites for the CO2 capture were synthesized via a facile assembly strategy associated with a direct solid-state heat dispersion process by introducing CuO into AC using Cu(NO3)2 as the copper source. The synthesized CuO/AC composites with various CuO contents were characterized by powder X-ray diffraction, scanning electron microscopy and nitrogen adsorption-desorption measurement, and the CO2 adsorption performance was investigated. The characterization results indicate that the Cu(NO3)2 species was well dispersed into the AC pore channels and then converted to a highly dispersed CuO after the activation process. The adsorption results reveal that the CO2 adsorption performance can be significantly improved by introducing CuO onto the AC surfaces, and the CuO(0.6)/AC composite with a CuO loading of 0.6 mmol/g AC shows a high CO2 adsorption capacity and adsorption selectivity and displays an excellent reversibility. Additionally, the calculated adsorption heat values of CO2 on the CuO(0.6)/AC composite are in the range of 27.3 to 33.9 kJ/mol.

Activated carbon (AC) supported MgO (MgO@AC) for CO2 capture has been facilely prepared with Mg(NO3)2 as precursor by a solid-state heat dispersion method. The prepared MgO@AC adsorbents with different magnesium loadings were characterized by X-ray diffraction (XRD), N2 adsorption/desorption and scanning electron microscope (SEM), and were investigated for the CO2 adsorption capacity, CO2 adsorption selectivity and cyclic stability. The characterization results reveal that the precursor of Mg(NO3)2 can be highly dispersed on the surfaces of the AC support and converted to MgO during the activation process at high temperatures. The experimental results show that the MgO@AC adsorbent with the MgO loadings of 5 mmol/g AC support achieves a high CO2 adsorption capacity, high CO2/N2 adsorption selectivity and excellent reversibility. Its good adsorption performance and facile fabrication process make it a promising adsorbent for CO2 capture from flue gases. In addition, the isosteric heat of CO2 adsorption on this adsorbent was calculated from the CO2 adsorption equilibrium isotherms at different temperatures using the Clausius–Clapeyron equation, the values are in the range of 45.4–20.1 kJ/mol.

Zeolite Y supported MgO (denoted as MgO@Y) composites have been successfully prepared using Mg(NO3)2 as precursor via a facile solid-state heat dispersion approach. The samples are characterized by X-ray diffraction and N2 adsorption/desorption, and investigated for CO2 adsorption performance including adsorption capacity, adsorption selectivity and stability. The results reveal that MgO can be highly dispersed on the surfaces of zeolite Y support after the activation at high temperatures, and the monolayer dispersion capacity of MgO on zeolite Y support is 3 mmol/g zeolite Y. The resulting MgO(3.0)@Y adsorbent with the magnesium loadings of 3 mmol/g zeolite Y displays a high CO2 adsorption capacity of 2.78 mmol/g at 500 kPa, which is about 28% higher than that of zeolite Y support. Moreover, the MgO(3.0)@Y adsorbent displays a high CO2/N2 adsorption selectivity of 32 and a excellent cyclic stability. Its good performance as well as its facile preparation process make it attractive candidate for the adsorption of CO2 in flue gas vents. In addition, the isosteric heat of CO2 adsorption on the MgO(3.0)@Y sample was calculated from the Clausius–Clapeyron equation, and the values the isosteric heats of adsorption lie in the range of 27.8–20.0 kJ/mol.

In this work, activated carbon (AC) supported CuCl (CuCl@AC) prepared with CuCl2 as precursor is investigated for CO separation from the synthesis gas mixture. Firstly, the CuCl@AC adsorbents are investigated for their CO reversible adsorption capacity at an operation temperature of 303 K. And a vacuum pressure swing adsorption (VPSA) process of CO separation from syngas utilizing the prepared CuCl@AC adsorbent is investigated at ambient temperature and 0.79 MPa through a dynamic optimization with Aspen Adsorption software. The integrated model is closer to a realistic PSA process, making the results of the simulation and optimization more convincing. The adsorption result reveals that the obtained CuCl@AC adsorbent with the copper loading of 7 mmol g−1 AC achieves a high reversible CO adsorption capacity and adsorption selectivity. The simulation result shows that, under optimal conditions, the CO product with the purity of 98.1 vol% can be separated from the syngas with the CO concentration of 32.3 vol% utilizing the prepared CuCl@AC adsorbent, and the recovery of CO is 92.9%.

A seed-induced method was applied to synthesize a series of ZSM-5 aggregates using silicalite-1 (S-1) as seeds. The samples were characterized by several techniques and studied in the methanol-to-gasoline (MTG) conversion reaction in a continuous fixed-bed reactor. The results showed that the molar ratios of Na2O/SiO2 and H2O/SiO2 in the precursors had great effects on the physicochemical and catalytic properties. The ZSM-5 aggregates with the highest crystallinity, external surface areas, micropore volumes, mesopore volumes and small primary crystal and aggregate sizes, obtained with the molar composition of 0.12Na2O–1SiO2–0.02Al2O3–25H2O-0.01Seed in the precursor, exhibited the highest stability.

ZSM-5 zeolite prepared by a hydrothermal method with the addition of seeds was treated with different concentrations of NaOH. The obtained samples were characterized by XRD, N2 adsorption, NH3-TPD, FT-IR, SEM, and studied in the catalytic performance of the hydration of cyclohexene to cyclohexanol. The characterization results showed that with the increase of NaOH concentration, the crystallinity of the treated samples decreased monotonously, and the acid sites of ZSM-5 zeolites first increased and then decreased, while more mesopores formed inside the ZSM-5 zeolites. The experimental results of catalytic performance showed that cyclohexene conversion can be improved through introducing the mesopores and enhancing the acidity of ZSM-5 with the NaOH treatment at a low concentration. The highest cyclohexene conversion of 12.8% was obtained when the concentrations of NaOH solution were in the range of 0.2–0.6 mol/L. The selectivity of cyclohexanol on all samples was higher than 99.6%.

Hierarchical ZSM-5 has been synthesized and treated with alkali (Na2CO3) solutions. The catalysts are characterized with many techniques and studied in the hydration of cyclohexene. The characterization results show that with increasing the concentrations of alkaline solutions, the crystallinities increase and then decrease; the sever treatment leads to the destroy of the zeolite crystals; the external surfaces and mesopore volumes increase; the amounts of weak and strong acid sites, as well as the Bronsted acid sites increase and then decrease, while the amounts of Lewis acid sites increase. In the hydration of cyclohexene, both the conversions of cyclohexene and the selectivity of cyclohexanol first increase and then decrease. The best performance is obtained over ZSM-5 treated with 0.5 M Na2CO3 solution with 13.0 % cyclohexene conversion and 99.3 % selectivity of cyclohexanol.

Mesoporous titanium silicalite-1(TS-1)was hydrothermally synthesized with the addition of triethanolamine( TEA)in the conventional process, and used in the cyclohexanone ammoximation in a continuous slurry reactor. The as-prepared TS-1 was characterized with X-ray diffraction(XRD), scanning electron microcopy( SEM), N2 adsorption-desorption, Fourier transform infrared (FT-IR)spectroscopy, UV-Visible(UV-Vis) diffuse reflectance spectra and UV Raman spectroscopy. The results indicated that the addition of TEA resulted in the formation of mesopores and the slight increase of framework titanium in TS-1. TS-1 synthesized with the addition of TEA exhibited a higher stability in the cyclohexanone ammoximation than that without the addition of TEA, attributing to the increase of mesopore volumes and the slight increase of the framework titanium in TS-1. However, when the addition of TEA was up to TEA/SiO2 ratio of 0.24, the crystallinity and framework titanium of TS-1 decreased markedly, and the average crystal sizes of TS-1 increased, with the catalyst stability becoming poor.