Catalytic CO2 Capture via Ultrasonically Activating Dually Functionalized Carbon Nanotubes.

High energy consumption and high cost have been the obstacles for large-scale deployment of all state-of-the-art CO2 capture technologies. Finding a transformational way to improve mass transfer and reaction kinetics of the CO2 capture process is timely for reducing carbon footprints. In this work, commercial single-walled carbon nanotubes (CNTs) were activated with nitric acid and urea under ultrasonication and hydrothermal methods, respectively, to prepare N-doped CNTs with the functional group of -COOH, which possesses both basic and acid functionalities. The chemically modified CNTs with a concentration of 300 ppm universally catalyze both CO2 sorption and desorption of the CO2 capture process. The increases in the desorption rate achieved with the chemically modified CNTs can reach as high as 503% compared to that of the sorbent without the catalyst. A chemical mechanism underlying the catalytic CO2 capture is proposed based on the experimental results and further confirmed by density functional theory computations.

[EMmim][NTf2 ]-a Novel Ionic Liquid (IL) in Catalytic CO2 Capture and ILs' Applications.

Ionic liquids (ILs) have been used for carbon dioxide (CO2 ) capture, however, which have never been used as catalysts to accelerate CO2 capture. The record is broken by a uniquely designed IL, [EMmim][NTf2 ]. The IL can universally catalyze both CO2 sorption and desorption of all the chemisorption-based technologies. As demonstrated in monoethanolamine (MEA) based CO2 capture, even with the addition of only 2000 ppm IL catalyst, the rate of CO2 desorption-the key to reducing the overall CO2 capture energy consumption or breaking the bottleneck of the state-of-the-art technologies and Paris Agreement implementation-can be increased by 791% at 85 °C, which makes use of low-temperature waste heat and avoids secondary pollution during CO2 capture feasible. Furthermore, the catalytic CO2 capture mechanism is experimentally and theoretically revealed.

Influence of drying and calcination temperatures for Ce-Cu-Al trimetallic composite catalyst on simultaneous removal H2S and PH3: Experimental and DFT studies.

This work explored the influences of the drying and calcination temperatures on a Ce-Cu-Al trimetallic composite catalyst for the simultaneous removal of H2S and PH3. The effects of both temperatures on the structural features and activity were examined. The density functional theory method was used to calculate adsorption energies and further analyze their adsorption behavior on different slabs. Experiments revealed suitable drying and calcination temperatures to be 60 and 500°C, respectively. The capacity reached 323.8 and 288.1 mg/g. Adjusting drying temperature to 60°C is more inclined to form larger and structured grains of CuO. Rising calcinating temperature to 500°C could increase the grain size and redox capacity of CuO to promote performance. Higher temperatures would destroy the surface structure and lead to a crystal phase transformation, which was that the CuO and Al2O3 were gradually recombined into CuAl2O4 with a spinel structure. The exposed crystal planes of surficial CuO and CuAl2O4 were determined according to characterization results. Calculation results showed that, compared with CuO (111), H2S and PH3 have weaker adsorption strength on CuAl2O4 (100) which is not conducive to their adsorption and removal.

US-guided percutaneous needle biopsy of the spleen using 18-gauge versus 21-gauge needles.

PURPOSE: To compare the techniques of sonographically (US)-guided percutaneous needle biopsy of the spleen using 18-gauge and 21-gauge needles. METHODS: Forty-two patients undergoing 43 spleen biopsy procedures for focal lesions (n = 27 [16 single, 11 multiple]) or diffuse splenomegaly (n = 15) were analyzed. Two groups were divided randomly according to needle type: group 1 comprised 25 patients biopsied with an 18-gauge cutting needle for histologic examination; group 2 comprised 17 patients biopsied with a 21-gauge needle for histologic and cytologic examinations. Diagnostic accuracy, complication rate, and number of needle passes were compared between the 2 groups. RESULTS: Correct histopathologic diagnosis was obtained in 36 cases, whereas incorrect diagnosis occurred in 6 cases. The accuracy of US-guided spleen biopsy in this series was 85.7%, with 1 patient (2.4%) having postprocedural hemorrhage. Compared with the 21-gauge needle, the 18-gauge needle had higher diagnostic accuracy (P < 0.05), required fewer needle passes (P < 0.05), and there was no significant difference in overall complication rate. CONCLUSION: Because biopsy with an 18-gauge needle yields larger and unfragmented samples with higher diagnostic rate compared with a 21-gauge needle, and no increased rate of major complication requiring surgical intervention, it may be advantageous to use an 18-gauge cutting needle in the US-guided needle biopsy of splenic lesions.