Xiaojun Lai,Nuoyi Huang,Xiaohua Zhao,Yang Li,Yao He,Jiesen Li,Jinhuan Deng,Xun-an Ning
Aromatic amines (AAs), a characteristic pollutant with electron-donating groups in textile industry , having high reactivity with reactive chlorine free radicals, is probably the precursor of chlorinated aromatic products in advanced oxidation treatment . In this study, Fe2+/peroxydisulfate (PDS)/Cl- and Fe2+/H2O2/Cl-systems were used to treat four kinds of AAs (5-Nitro-o-toluidine (NT), 4-Aminoazobenzol (AAB), O-Aminoazotoluene (OAAT), 4,4′-Methylene-bis(2-chloroaniline) (MBCA)) in simulated wastewater, and the selectivity of various reactive species to AAs, the oxidation law and pathway of AAs were explored. The results showed that dichloride anion radical (Cl2·-) could effectively oxidize four AAs, and chlorine radical (·Cl) was strongly reactive to AAB and MBCA, especially MBCA. The largest f – (Fukui function) of MBCA is 0.0822, which is the lowest of the four AAs, so ·Cl might be more sensitive to electrophilic point than hydroxyl radical (·OH). The oxidation pathway of NT and MBCA showed that ·Cl mainly played the role of electron transfer to AAs instead of generating chlorinated products, but the addition of ·OH to –NH2 generated aromatic nitro compounds with higher toxicity than NT and MBCA. Therefore, the electron transfer of ·Cl and Cl2·- could not only improve the removal of AAs but also reduce the generation of toxic products. This study found that the reactivity of reactive chlorine free radicals was not necessarily related to chlorination, which provided a theoretical basis for the further studies into the formation mechanism of chlorination products.
This study develops a catalytic system using pyruvic acid (PYA) and Fe2+ to efficiently coproduce xylo-oligosaccharides (XOS) and (manno-oligosaccharides) MOS from food material (Gleditsia sinensis Lam. fruit.) and its waste peel, respectively. The system achieved maximum yields of 67.12% XOS and 57.32% MOS without toxic byproducts such as furfural and 5-hydroxymethylfurfural (5-HMF) below 130 °C. The process employs a two-stage mechanism, where PYA cleaves galactose side chains and xylan backbones, while Fe2+ stabilizes β-1,4-glycosidic bonds, resulting in polymerization degree ratios of X2–3/X4–5 at 0.975 and M2–3/M4–5 at 0.96. The composite oligosaccharides, PFMX, showed significant prebiotic effects, enhancing Bifidobacterium adolescentis growth to 3.4 × 108 CFU/mL─144% higher than commercial fructooligosaccharides (FOS). The concentration of short-chain fatty acids (SCFAs) was 15.09 g/L, with specific products propionic acid (1.44 g/L) and butyric acid (0.15 g/L). PFMX effectively regulates substrate utilization and SCFA metabolism, offering a promising strategy for developing functional foods that target gut inflammation.
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