A novel adsorption membrane with excellent physical prop erties was prepared by immobilizing bayberry tannin onto hide collagen fiber mem brane. The equilibrium adsorption capacities of the membrane to Pb（Ⅱ） an d H...A novel adsorption membrane with excellent physical prop erties was prepared by immobilizing bayberry tannin onto hide collagen fiber mem brane. The equilibrium adsorption capacities of the membrane to Pb（Ⅱ） an d Hg（Ⅱ） were 39.9 mg·g-1 and 75.2 mg·g-1 respectively at 303 K when the equilibrium concentrations of Pb（Ⅱ） and Hg（Ⅱ） were 192.1 mg·L-1 and 23.5 mg·L-1.Higher temperature led to higher ad sorption capacity. The adsorption isotherm of Pb（Ⅱ） on the tannin immobi lized membrane could be described by the Langmuir model, however, the isotherms of Hg（Ⅱ） tended to be fitted by the Freundlich model. The data of adsorp tion rate could be well described by the pseudo-second-order rate model. Cont inuous adsorption experiments indicated that multi-layer membranes were efficie nt for the removal of Pb（Ⅱ） and Hg（Ⅱ） from water. The membrane wa s easy to be regenerated by 0.1 mol·L-1 HNO3 after continuous adsorpti on and no considerable change of its adsorption property was observed after adso rption and desorption cycles.展开更多
文摘用吸附法固定脂肪酶时,膜材料的亲疏水性对固定化酶的量、比活力和活力稳定性等有很大影响.今以柱状假丝酵母脂肪酶和猪胰脂肪酶为研究对象,选取了8种亲疏水性不同的膜材料（醋酸纤维素、聚丙烯腈、聚酰胺、聚砜、聚醚砜、聚偏二氟乙烯、聚丙烯和聚四氟乙烯）作为固定化载体,用吸附法制备了固定化脂肪酶膜.研究结果表明,强疏水性聚四氟乙烯和聚丙烯膜对两种酶的吸附量都比较大,且固定化酶的比活力和活力回收率比较高,聚四氟乙烯固定化柱状假丝酵母酶比游离态酶的半衰期提高了6倍以上.强亲水性醋酸纤维素膜对猪胰脂肪酶的吸附量比聚四氟乙烯高,但是固定化酶的比活力、活力回收率比强疏水性膜低,而接触角在40°～50°的聚酰胺膜和聚砜膜的吸附量最小.因此吸附法制备固定化脂肪酶膜,选择聚丙烯膜和聚四氟乙烯膜是合适的,制备的优化条件为吸附温度25℃,酶溶液的pH为7.5,吸附时间10 h.
文摘A novel adsorption membrane with excellent physical prop erties was prepared by immobilizing bayberry tannin onto hide collagen fiber mem brane. The equilibrium adsorption capacities of the membrane to Pb（Ⅱ） an d Hg（Ⅱ） were 39.9 mg·g-1 and 75.2 mg·g-1 respectively at 303 K when the equilibrium concentrations of Pb（Ⅱ） and Hg（Ⅱ） were 192.1 mg·L-1 and 23.5 mg·L-1.Higher temperature led to higher ad sorption capacity. The adsorption isotherm of Pb（Ⅱ） on the tannin immobi lized membrane could be described by the Langmuir model, however, the isotherms of Hg（Ⅱ） tended to be fitted by the Freundlich model. The data of adsorp tion rate could be well described by the pseudo-second-order rate model. Cont inuous adsorption experiments indicated that multi-layer membranes were efficie nt for the removal of Pb（Ⅱ） and Hg（Ⅱ） from water. The membrane wa s easy to be regenerated by 0.1 mol·L-1 HNO3 after continuous adsorpti on and no considerable change of its adsorption property was observed after adso rption and desorption cycles.
