Separations

Siraitia grosvenorii (Swingle) C. Jeffrey is widely recognized for its anti-inflammatory properties, as well as its roles in lung purification, phlegm elimination, intestinal function regulation, and anti-tumor activity. Its pharmacological activity is attributed to a diversity of functional components. However, due to the extensive application of sweet glycosides in food additives, there have been few studies on non-sweet glycosides, particularly those with high polarity. This paper investigates the chemical constituents in the non-sweet glycosides fraction of S. grosvenorii juice. First, an MCI GEL CHP20P chromatographic column was utilized to enrich the non-sweet glycosides fraction. Furthermore, two-step medium-pressure liquid chromatography (MPLC) was performed for the efficient preparative separation of high-polarity non-sweet glycosides with similar structures, using C18 and silica gel as stationary phases, respectively. Seven non-sweet glycoside compounds were identified through NMR and mass spectrometry analyses, including three new compounds (4-hydroxyphenylethanol 4-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside, 4-hydroxyphenylethanol 4-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside and n-butanol 1-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside), as well as four known ones (α-D-glucopyranosyl-(1→4)-D-glucose, α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside, methoxy hydroquinone diglucoside, and β-D-glucopyranoside). The results demonstrate that mixed-mode MPLC using different stationary phases is an efficient approach for separating non-sweet glycosides from S. grosvenorii.

Grinding is an essential process in mineral processing. Hydrogen-based mineral phase transformation, used to efficiently process refractory iron ores, can alter the physical and chemical properties of the ore, affecting its grinding characteristics. This paper uses iron ore from Baoshan, Shanxi Province, as the raw material for laboratory-scale hydrogen-based mineral phase transformation (HMPT) experiments and grinding tests. It examines the impact of four cooling methods on the ore’s grinding characteristics. The results show that samples cooled in a reducing atmosphere to 200 °C and then water-quenched exhibit the best relative grindability. For the same grinding time, the content of coarse-sized particles (+0.074 mm) in the product is lowest, while the fine-sized particles (−0.030 mm) is highest. The grinding kinetic parameters of the samples with this cooling method are the highest. After 2 min of grinding, the value of n is 1.3363, and the particle size distribution of the product is the most uniform. The BET and SEM test results indicate that samples with this cooling method have more internal pores, the largest pore size, and the most surface cracks and pores. This paper clarifies the effects of the HMPT cooling methods on grinding characteristics, providing a theoretical foundation for the efficient separation of iron ores.

Nitrogen dioxide (NO₂) is a major atmospheric pollutant and also a recoverable nitrogen resource, for which adsorption offers a promising technical pathway. This review systematically summarizes the recent progress in the removal of NO₂ from flue gas by adsorption methods, with a focus on material-level and process-level advancements. From the material perspective, three representative adsorbents—zeolites, activated carbons, and metal oxides—are comparatively evaluated in terms of their physicochemical properties, active sites, and adsorption mechanisms. Emphasis is placed on their adsorption capacity, selectivity, and hydrothermal stability, supported by both experimental and theoretical insights. From the process perspective, four adsorption-based technologies—Pressure Swing Adsorption (PSA), Temperature Swing Adsorption (TSA), Vacuum Pressure Swing Adsorption (VPSA), and Vacuum Temperature Swing Adsorption using multiple Gas circulations (GVTSA)—are analyzed regarding their principles, operational workflows, and engineering applications, with particular attention to the process intensification potential of GVTSA. The review identifies existing challenges in terms of material stability under complex conditions and process scalability, especially for severe environments such as nuclear reprocessing tail gases. Finally, future research directions are proposed toward developing multifunctional composite adsorbents with high capacity, strong environmental tolerance, and excellent regenerability, along with optimized and integrated adsorption processes, to achieve efficient NO₂ abatement and high-value recovery.