用直接观察法、酒石酸亚铁法和铬黑 T 祛对绿茶茶汤组分与23种金属离子的络合性能进行了研究,结果表明,有22种金属离子可与茶汤组分发生络合或还原络合反应,其中有10种金属离子参与了茶多酚的络合。钙离子可与茶汤组分生成低溶解度的络...用直接观察法、酒石酸亚铁法和铬黑 T 祛对绿茶茶汤组分与23种金属离子的络合性能进行了研究,结果表明,有22种金属离子可与茶汤组分发生络合或还原络合反应,其中有10种金属离子参与了茶多酚的络合。钙离子可与茶汤组分生成低溶解度的络合物,其溶解度及稳定性可随反应溶液 pH 升高而下降。钙络合沉淀中的主要茶汤组分是茶多酚,其中以酯型儿茶素含量最高。展开更多
Chitosan is a nontoxic natural polysaccharide with good biocompatibility.It can form polymer\|metal complexes with many metal cations for its extra electron pair of nitrogen.The complexes exhibit high sorptive capacit...Chitosan is a nontoxic natural polysaccharide with good biocompatibility.It can form polymer\|metal complexes with many metal cations for its extra electron pair of nitrogen.The complexes exhibit high sorptive capacity and good selectivity for urea.The sorption capacity was influenced by the metal content in the complex,time of sorption,concentration of urea etc.The sorption capacities were 83.6,79.1,72.9,69.4 and 53.4 mg/g for urea by the chitosan metal complexes of Cu(Ⅱ),Cd(Ⅱ),Co(Ⅱ),Zn(Ⅱ) and Fe(Ⅲ),respectively at pH 6.0 and the concentration of urea being 1 300 mg/L.展开更多
文摘用直接观察法、酒石酸亚铁法和铬黑 T 祛对绿茶茶汤组分与23种金属离子的络合性能进行了研究,结果表明,有22种金属离子可与茶汤组分发生络合或还原络合反应,其中有10种金属离子参与了茶多酚的络合。钙离子可与茶汤组分生成低溶解度的络合物,其溶解度及稳定性可随反应溶液 pH 升高而下降。钙络合沉淀中的主要茶汤组分是茶多酚,其中以酯型儿茶素含量最高。
文摘Chitosan is a nontoxic natural polysaccharide with good biocompatibility.It can form polymer\|metal complexes with many metal cations for its extra electron pair of nitrogen.The complexes exhibit high sorptive capacity and good selectivity for urea.The sorption capacity was influenced by the metal content in the complex,time of sorption,concentration of urea etc.The sorption capacities were 83.6,79.1,72.9,69.4 and 53.4 mg/g for urea by the chitosan metal complexes of Cu(Ⅱ),Cd(Ⅱ),Co(Ⅱ),Zn(Ⅱ) and Fe(Ⅲ),respectively at pH 6.0 and the concentration of urea being 1 300 mg/L.
