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
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.
