JOURNAL OF FOOD SCIENCE
·
2019
·Vol. 84
·期 4
·754-761
·
IF 2.081
Hui Zhang,Xiu-ting Cai,Qing-hua Tian,Lin-xia Xiao,Zhen Zeng,Xin-tong Cai,Ji-zhong Yan,Qing-yong Li
Four polysaccharide fractions (P-1: 71.40%, P-2: 1.95%, P-3: 1.14%, P-4: 1.64%) were isolated from crude Polygonatum sibiricum polysaccharide (PSP), processed by water extraction, ethanol precipitation, and further separated with diethylaminoethyl cellulose-52 anion-exchange chromatography. Their molecular weights and monosaccharide compositions were characterized by high performance gel chromatography with evaporative light scattering detector and ultraviolet–visible detector. The antioxidant activity of four polysaccharides fractions were assessed by the electron transfer menchanism (DPPH, ferric reducing power, and ABST assays) and chelation of transition metals (Fe 2+ and Cu 2+ chelation ability). The highest content fraction P-1 exhibited the lowest antioxidant activity, and the ranking of antioxidant capacity was P-4 > P-3 > P-2 > PSP > P-1. After processed by microwave-assisted degradation, the molecular weight of P-1 was decreased from 2.99 × 10 5 to 2.33 × 10 3 Da, while the antioxidant activity of degraded P-1 was about eightfold higher than natural P-1. These results indicated that the proposed microwave-assisted degradation approach was an efficacious methodology to improve their bioactivity by lower the molecular weight of polysaccharides. Practical Application This study provided an environmentally friendly, convenient and efficient microwave-assisted degradation technology to process the neutral polysaccharides from Polygonatum sibiricum . The results could be used for the development and utilization of various plant polysaccharides as a kind of food supplement in our daily life.
研究领域:
食品科学
·
植物化学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2012
·
IF 5.228
Erdan Hu,Hefa Cheng,Yuanan Hu
The herbicide atrazine is a common pollutant in reservoirs and other sources of drinking water worldwide. The adsorption of atrazine from water onto zeolites CBV-720 and 4A, mesoporous silica MCM-41, quartz sand, and diatomite, and its microwave-induced degradation when sorbed on these minerals, were studied. Dealuminated HY zeolite CBV-720 exhibited the highest atrazine sorption capacity among the mineral sorbents because of its high micropore volume, suitable pore sizes, and surface hydrophobicity. Atrazine sorbed on the minerals degraded under microwave irradiation due to interfacial selective heating by the microwave, while atrazine in aqueous solution and associated with PTFE powder was not affected. Atrazine degraded rapidly in the micropores of CBV-720 under microwave irradiation and its degradation intermediates also decomposed with further irradiation, suggesting atrazine could be fully mineralized. Two new degradation intermediates of atrazine, 3,5-diamino-1,2,4-triazole and guanidine, were first identified in this study. The evolution of degradation intermediates and changes in infrared spectra of CBV-720 after microwave irradiation consistently indicate the creation of microscale hot spots in the micropores and the degradation of atrazine following a pyrolysis mechanism. These results indicate that microporous mineral sorption coupled with microwave-induced degradation could serve as an efficient treatment technology for removing atrazine from drinking water.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2017
·
IF 5.715
Yuanan Hu,Yuanzhen He,Hefa Cheng
N -nitrosodimethylamine (NDMA), a highly toxic and carcinogenic disinfection byproduct , cannot be efficiently removed by conventional water treatment processes , while sorption by microporous minerals, followed by destruction with microwave irradiation has been developed as a promising alternative. This work examined the impact of surface cation density and type on sorption of NDMA on dealuminated ZSM-5 zeolites , and on microwave-induced degradation of the sorbed NDMA, as well as the non-thermal effect of microwave. NDMA sorption was found to increase with the framework Si/Al ratio of dealuminated ZSM-5 zeolites (i.e., decreasing density of surface cations), and was also influenced by the type of surface cations. Degradation of the sorbed NDMA proceeded faster with increases in the power level of microwave and in the micropores with higher densities of surface cations, which was attributed to the increases in the number and/or temperature of micro-scale “hot spots” formed by microwave dielectric superheating of the surface cations. The degradation rate of sorbed NDMA was also found to be inversely correlated with the hydration free energy of surface cations present in the zeolite micropores . The apparent activation energy estimated from the temperature dependence of NDMA degradation in the micropores under microwave irradiation was 18.2 kJ/mol, which is much lower than those of typical thermolysis reactions and is indicative of significant contribution from the non-thermal effect of microwave.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2021
·
IF 5.909
Man-Qing Ai,Hao Du,Shuang-Shuang Lv,Xue-Gang Chen,Chu-Qing Zhang,Wei Cai,Wen-Li Qin,Ying Ye,Chun-Hui Tao
Microwave-enhanced degradation is an effective method to remove organic contaminants from aqueous solutions. In this study, we prepared a novel iron sulfide/talc composite. Under microwave irradiation, the hydroxyl and sulfate radicals are rapidly released from the as-prepared FeS x /talc composite (TF), which could remove 106.8 mg/(min·g) of 2,4,6-TCP in 4 min. The maximum chemical oxygen demand (COD) removal was more than 90.1% when the concentration of TF is 1 g/L and the irradiation time of microwave radiation was 5 min, significantly higher than that treated by FeS x particles or talc. It is attributed to the synergetic effect between talc layers and FeS x particles, which greatly enhances the catalytic degradation performance of the composite for organic pollutants . With the advantages of low cost, high physico-chemical stability, and high reusability, this novel FeS x /talc composite could be a potential treating material for rapidly remove organic pollutants from wastewater.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）