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以提取的水培茶树龙井43根细胞壁为供试材料,研究了茶树根细胞壁对Pb的吸附作用.结果表明:酸性条件下茶树根细胞壁对Pb的吸附量随着吸附液初始pH值的升高而增大,当初始pH值在2.0~4.5时Pb吸附量快速上升.在吸附液初始pH值为4.5的条件下,当吸附达到平衡时,随着吸附液Pb浓度的提高,茶树根细胞壁对Pb的吸附量增大,其吸附行为更适合用Freundlich吸附模型拟合.当达到吸附平衡时,根细胞壁的Pb吸附总量为9.7mg·g-1,当吸附时间达到320 min时根细胞壁对Pb的吸附量可以达到平衡吸附量的90%,从解吸动力学曲线来看,在60 min时Pb的解吸量可以达到平衡解吸量的50%,吸附、解吸动力学方程更适合用二级速率方程描述.根细胞壁分别经酯化、果胶酶改性、氨基甲基化改性处理后,其对Pb的累积吸附量与未改性处理相比分别降低了51.1%、41.3%和10.8%,表明根细胞壁上的-COOH、半乳糖醛酸多聚物果胶质及-NH2在一定程度上参与了Pb在茶树根细胞壁上的吸附.
The results showed that the adsorption capacity of Pb on root cell wall of tea plant under acidic conditions increased with the increase of the initial pH of the adsorption solution But the Pb adsorption increased rapidly when the initial pH was between 2.0 and 4.5. When the initial pH value of the adsorption solution was 4.5, when the adsorption reached the equilibrium, the Pb Pb adsorption increased, and the adsorption behavior was more suitable for fitting with Freundlich adsorption model. When the equilibrium of adsorption was reached, the total amount of Pb adsorption on the root cell wall was 9.7 mg · g-1. When the adsorption time reached 320 min, Pb adsorption capacity can reach 90% of the equilibrium adsorption capacity, desorption kinetics curve point of view, at 60 min Pb desorption amount can reach 50% of the equilibrium desorption amount, adsorption and desorption kinetics equation more suitable for the second rate The equation describes that the cumulative adsorption capacity of Pb to root cell wall was reduced by 51.1%, 41.3% and 10.8% respectively compared with unmodified treatment after esterified, pectinase modified and aminomethylated modified, , Indicating -COOH, galacturonic acid on the root cell wall Homopolymers and pectin -NH2 involved to some extent adsorbed onto the root tea Pb cell wall.