As part of a systematic research on the interaction mechanism between polysaccharides and mineral surfaces, ive extend the studies on dextrin adsorption to real minerals such as oxides and salt-type minerals, based on...As part of a systematic research on the interaction mechanism between polysaccharides and mineral surfaces, ive extend the studies on dextrin adsorption to real minerals such as oxides and salt-type minerals, based on previous studies of model systems {surface-modified quartz ). The minerals tested include hematite, rutile, fluorite, calcite, apatite, etc. It is observed that dextrin adsorption on these minerals is strongly pH-depen-dent, with adsorption maxima appearing at pH values around the isoelec-tric points of the minerals, indicating interactions zvith surface metal hy-droxide species. X-ray photoelectron spectroscopy (XPS) measurements re-veal electronic binding energy shifts or Auger parameter changes of miner-al surface elements after dextrin adsorption , pointing to a chemical mecha-nism of interaction. Furthermore, it is observed that the reaction of miner-als with moderate amounts of fatty acids prior to dextrin addition results in an increase in dextrin adsorption, whereas excessive fatty acids do the opposite. Combined with our previous studies, it is concluded from the ex-perimental observations that although surface hydrophobic species alone do not have any effect on dextrin adsorption, they synergistically enhance the adsorption when present together with surface metallic sites.展开更多
Based on analytical data of mineral phase constituents at three sections from Tern Lake, West Lake and Kitezh Lake in the Fildes Peninsula of King George Island, Antarctica, the characteristics of mineral phase consti...Based on analytical data of mineral phase constituents at three sections from Tern Lake, West Lake and Kitezh Lake in the Fildes Peninsula of King George Island, Antarctica, the characteristics of mineral phase constituents, material source and their environmental implication have been discussed. Research results indicate that lacustrine deposits came primarily from widespread volcanic rocks at the peninsula. Under cold and dry condition in Antarctica, the weathering process of the parent rocks in some area is mainly physical weathering with a weak chemical one. The relation curves of abundance of kaolinite and calcite against deposition age change steeply at the boundary between lacustrine and glacial deposits, indicating that the corresponding environment changes are abrupt, which may be related to different transportation fashion of both different deposits and the protection of glacial deposits.展开更多
Mineral constituents and their weathering in yellow-red soils derived from granite in middle and lower reaches of the Yangtze R iver were studied. Light minerals in fractions greater than silt contained over 80% quart...Mineral constituents and their weathering in yellow-red soils derived from granite in middle and lower reaches of the Yangtze R iver were studied. Light minerals in fractions greater than silt contained over 80% quartz and feldspar, and heavy ones contained more than 60% various iron minerals and about 30% mica and hornblende. Kaolinite was the main clay mineral, the content of which was about 300 -400 g/ kg. Quartz was weathered very weakly, Ca-feldspar was weathered over 65%, and about 25% of Na-feldspar was weathered. The vermiculitisation of mica was relativly obvious, > 50% of mica being weathered to vermiculite. Weatherable minerals were also obviously weathered, the weathering being about 60%. Soil vermiculite was evolved through the process of mica→hydromica→vermiculite-chlorite→vermiculite, which was closely related to leaching situation and oxidic condition.展开更多
Rosa x alba is cultivated almost exclusively for the production of aromatic water and fruits widely used as ingredients in some traditional food preparations sold commercially.Results of the proximate and elemental an...Rosa x alba is cultivated almost exclusively for the production of aromatic water and fruits widely used as ingredients in some traditional food preparations sold commercially.Results of the proximate and elemental analyses revealed that flowers exhibited higher moisture content while the dry matter content was higher in leaves.Total fat and ash was higher in fruits when compared with leaves and flowers.All studied organs were found to be rich in essential mineral such as K,Ca,P and Mg.Qualitative and quantitative analysis of the volatile oils revealed different composition patterns between organs.Linalool and geraniol were found as major constituents of the leaf oil whereas 2-phenethyl alcohol and eugenol were the major constituents of the floral oil.In contrast,fruits showed very distinct composition and alkanes/alkenes were found to have the major contribution.The present composition could justify the traditional use of Rosa x alba which could be considered as a potential source of essential minerals and volatile constituents.展开更多
文摘As part of a systematic research on the interaction mechanism between polysaccharides and mineral surfaces, ive extend the studies on dextrin adsorption to real minerals such as oxides and salt-type minerals, based on previous studies of model systems {surface-modified quartz ). The minerals tested include hematite, rutile, fluorite, calcite, apatite, etc. It is observed that dextrin adsorption on these minerals is strongly pH-depen-dent, with adsorption maxima appearing at pH values around the isoelec-tric points of the minerals, indicating interactions zvith surface metal hy-droxide species. X-ray photoelectron spectroscopy (XPS) measurements re-veal electronic binding energy shifts or Auger parameter changes of miner-al surface elements after dextrin adsorption , pointing to a chemical mecha-nism of interaction. Furthermore, it is observed that the reaction of miner-als with moderate amounts of fatty acids prior to dextrin addition results in an increase in dextrin adsorption, whereas excessive fatty acids do the opposite. Combined with our previous studies, it is concluded from the ex-perimental observations that although surface hydrophobic species alone do not have any effect on dextrin adsorption, they synergistically enhance the adsorption when present together with surface metallic sites.
文摘Based on analytical data of mineral phase constituents at three sections from Tern Lake, West Lake and Kitezh Lake in the Fildes Peninsula of King George Island, Antarctica, the characteristics of mineral phase constituents, material source and their environmental implication have been discussed. Research results indicate that lacustrine deposits came primarily from widespread volcanic rocks at the peninsula. Under cold and dry condition in Antarctica, the weathering process of the parent rocks in some area is mainly physical weathering with a weak chemical one. The relation curves of abundance of kaolinite and calcite against deposition age change steeply at the boundary between lacustrine and glacial deposits, indicating that the corresponding environment changes are abrupt, which may be related to different transportation fashion of both different deposits and the protection of glacial deposits.
文摘Mineral constituents and their weathering in yellow-red soils derived from granite in middle and lower reaches of the Yangtze R iver were studied. Light minerals in fractions greater than silt contained over 80% quartz and feldspar, and heavy ones contained more than 60% various iron minerals and about 30% mica and hornblende. Kaolinite was the main clay mineral, the content of which was about 300 -400 g/ kg. Quartz was weathered very weakly, Ca-feldspar was weathered over 65%, and about 25% of Na-feldspar was weathered. The vermiculitisation of mica was relativly obvious, > 50% of mica being weathered to vermiculite. Weatherable minerals were also obviously weathered, the weathering being about 60%. Soil vermiculite was evolved through the process of mica→hydromica→vermiculite-chlorite→vermiculite, which was closely related to leaching situation and oxidic condition.
文摘Rosa x alba is cultivated almost exclusively for the production of aromatic water and fruits widely used as ingredients in some traditional food preparations sold commercially.Results of the proximate and elemental analyses revealed that flowers exhibited higher moisture content while the dry matter content was higher in leaves.Total fat and ash was higher in fruits when compared with leaves and flowers.All studied organs were found to be rich in essential mineral such as K,Ca,P and Mg.Qualitative and quantitative analysis of the volatile oils revealed different composition patterns between organs.Linalool and geraniol were found as major constituents of the leaf oil whereas 2-phenethyl alcohol and eugenol were the major constituents of the floral oil.In contrast,fruits showed very distinct composition and alkanes/alkenes were found to have the major contribution.The present composition could justify the traditional use of Rosa x alba which could be considered as a potential source of essential minerals and volatile constituents.
