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1.
ACS Omega ; 8(30): 27612-27620, 2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37546616

RESUMEN

Developing non-carbon-based adsorbents is essential for removing heavy metals from post-incineration flue gas. In this study, a new high-temperature-resistant adsorbent-activated boron nitride (BN) was prepared using precursors combined with a high-temperature activation method. The adsorption characteristics of BN for Zn, Cu, and Cd in simulated flue gas and sludge incineration flue gas were investigated using gas-phase heavy metal adsorption experiments. The results showed that BN prepared at 1350 °C for 4 h had defect structures, abundant pores, functional groups, and a high specific surface area of 658 m2/g. The adsorption capacity of BN in simulated flue gases decreases with increasing adsorption temperature, whereas it is always higher than that of activated carbon (AC). The total adsorption capacities for Zn, Cu, and Cd were the highest at 50 °C with 48.3 mg/g. BN had strong adsorption selectivity for Zn, with a maximum adsorption capacity of 54.45 mg/g, and its adsorption process occurred mainly on the surface. Cu and Cd inhibited Zn adsorption, leading to a decrease in the Zn adsorption capacity. In sludge incineration flue gas, BN can quickly reach adsorption equilibrium. The BN had a synergistic disposal capacity for heavy metals and fine particulate matter. The maximum adsorption capacity was reduced compared to the simulated flue gas adsorption capacity, which was 5.1 mg/g. However, BN still exhibited a strong adsorption selectivity for Zn, and its adsorption capacity was always greater than that of AC. The rich functional groups and high specific surface area enable BN to physically and chemically double-adsorb heavy metals.

2.
J Chem Phys ; 155(3): 034202, 2021 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-34293873

RESUMEN

Benefitting from the capability of recording scalar (J) couplings and bonding information, 2D J-resolved NMR spectroscopy constitutes an important tool for molecular structure analysis and mixture component identification. Unfortunately, conventional 2D J-resolved experiments generally encounter challenges of insufficient spectral resolution and strong coupling artifacts. In this study, a general NMR approach is exploited to record absorption-mode artifact-free 2D J-resolved spectra. This proposal adopts the advanced triple-spin-echo pure shift yielded by chirp excitation element to eliminate J coupling splittings and preserve chemical shifts along the F2 dimension, and it additionally utilizes the echo-train J acquisition to reveal the multiplet structure along the F1 dimension in accelerated experimental acquisition. Thus, it permits one to extract multiplet structure information from crowded spectral regions in one-shot experiments, with considerable resolution advantage resulting from completely decoupling F2 dimension and absorption-mode presentation, thus facilitating analysis on complex samples. More importantly, this method grants the superior performance on suppressing strong coupling artifacts, which have been affirmed by experiments on a series of chemical samples. As a consequence, this proposed method serves as a useful tool for J coupling measurements and multiplet structure analyses on complex samples that contain crowded NMR resonances and strong coupling spin systems, and it may exhibit broad application potentials in fields of physics, chemistry, and medical science, among others.

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