ABSTRACT
By constructing nanofluid system, trace functionalized nanoparticles can significantly enhance the absorption performance of basic liquid. In this work, amino functionalized carbon nanotubes (ACNTs) and carbon nanotubes (CNTs) were introduced into alkaline deep eutectic solvents to build nanofluid systems and used for the dynamic absorption of H2S. The experiment results showed that the introduction of nanoparticles can significantly enhance the H2S removal performance of original liquid. When performing H2S removal experiments, the optimal mass concentrations of ACNTs versus CNTs were 0.05 % and 0.01 %, respectively. The characterization showed that the surface morphology and structure of the nanoparticles unchanged significantly during the absorption-regeneration process. A double mixed gradientless gas-liquid reactor was used to explore the gas-liquid absorption kinetics characteristics of the nanofluid system. It was found that the gas-liquid mass transfer rate increased significantly after the addition of nanoparticles. The highest total mass transfer coefficient of the nanofluid system of ACNTs was increased to more than 400 % of the value before the addition of nanoparticles. The analysis showed that the shuttle effect and hydrodynamic effect of nanoparticles play important role in the process of enhancing gas-liquid absorption, and the amino functionalization enhanced the shuttle effect of nanoparticles significantly.
ABSTRACT
The nanoparticles of zeolitic imidazolate framework (ZIF-67) were synthesized and added to ethanolamine/deep eutectic solvent solution to form nanofluid system. The dynamic removal performance of prepared nanofluid system for hydrogen sulfide was investigated. For the system based on choline chloride and urea, the introduction of nanoparticles showed significant enhancement effect on the desulfurization performance. The optimal mass fraction of nanoparticles in nanofluid systems were identified as 0.1%. Besides, the experimental results showed that the prepared nanofluid systems have high regeneration performance, and the presence of moderate moisture is beneficial to the regeneration process. The absorbents and nanoparticles before and after absorption were characterized by Fourier transform infrared spectra, nuclear magnetic resonance, scanning electron microscope, energy dispersive spectrum, X-ray diffraction and X-ray photoelectron spectroscopy. The characterization results showed that the surface of nanoparticle was covered by CoS2 after absorption.
ABSTRACT
The desulfurization and regeneration performance of nanofluids composed of oxidizing ionic liquids and four inert nanoparticles are investigated. The addition of different nanoparticles has been proved to have enhancement effect on the H2S removal performance of oxidizing ionic liquids. The nanofluids with SiO2 nanoparticles showed the most significant strengthening desulfurization performance as well as regeneration performance. The optimal weight ratio of SiO2 nanoparticles in nanofluids was confirmed as 0.5%. The regeneration efficiency of the optimal nanofluid system can exceed 88%, which is far higher than that before the addition of SiO2 nanoparticles. The mass transfer coefficient increased significantly after the addition of nanoparticles. The nanoparticles and nanofluids before and after absorption were characterized by Fourier transform infrared spectra, nuclear magnetic resonance, scanning electron microscope, transmission electron microscope, energy dispersive spectrum and X-ray photoelectron spectroscopy. It was found that the structure and morphology of SiO2 nanoparticles remained basically unchanged in the absorption-regeneration process. The main final desulfurization product was identified as sulfate.
ABSTRACT
Deep eutectic solvent (DES) was applied as the solvent of iron/alcohol amine system, and the prepared iron/ethanolamine/DES system was found to be a good desulfurizer for H2S removal. The absorbents were characterized by Fourier transform infrared spectroscopy. The iron/ethanolamine/DES system showed a significantly enhanced desulfurization performance compared with DES solution of iron or alcohol amine separately. Besides, the absorbents showed relatively stable desulfurization performance, which could keep a high H2S removal efficiency in a wide temperature range from 30-90°C. The iron/ethanolamine/DES system could be recycled for at least three times. The desulfurization product was analyzed by energy dispersive spectrum and X-ray diffraction, and the desulfurization product was identified as sulfur element.
Subject(s)
Ethanolamine , Iron , Solvents , Spectroscopy, Fourier Transform Infrared , SulfurABSTRACT
Tantalum hydroxide exhibits the ability for the removal of phosphate from aqueous solution. The kinetic study, adsorption isotherm, thermodynamic study, desorption, and foreign anions effect were examined in batch experiments. The kinetic process was very well described by a pseudo-second-order rate model. The adsorption isotherms showed that phosphate uptake fitted with a Langmuir-type model very well, with an increase of PO4(3-) adsorption capacity from 78.5 to 97.0 mg/g when the temperature increased from 298 to 338 K. The negative values of deltaG(0) and the positive values of deltaH(0) indicated that the phosphate adsorption process was spontaneous and endothermic naturally. While the deltaS(0) values obtained were positive, indicating an increase in randomness at the solid-liquid interface during the adsorption. Foreign anions tests showed that the presence of competitive ions cause minimal interference with the adsorption of phosphate on tantalum hydroxide.
