中文摘要：

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范围内时Pb吸附量快速上升。在吸附液初始pH值为4.5的条件下,随着吸附液平衡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320min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60min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。

英文摘要：

A research was done to study the Pb adsorption by the root cell wall of tea plant extracted from Longjing 43. It was indicated that the amount of Pb adsorbed by the root cell wall increased with augment of the initial pH of the solution under acidic condition, dramatically as the pH ranged from 2.0 to 4.5. The amount of Pb increased with the Pb concentration in the solution at pH 4.5, which could be well fitted by the Freundlich adsorption model. The adsorbed Pb reached 9.7 mg·g-1 under equilibrium condition, 90% of which was adsorbed in 320 minutes, while 50% was desorbed in 60 minutes based on the desorption dynamic curve. The kinetics of both adsorption and desorption could be well described by a second-order rate equation. The amount of absorbed Pb by the root cell wall varied after modified treatments, reducing by 51.1% after esterifing, 41.3% with pectinase, and 10.8% via aminomethylation, suggesting that carboxyl, galacturonic acid, pectin and amino, to some extent, all took part in the Pb adsorption by the root cell wall.