PROTON AND COPPER ADSORPTION TO MAIZE AND SOYBEAN ROOT CELL-WALLS
PROTON AND COPPER ADSORPTION TO MAIZE AND SOYBEAN ROOT CELL-WALLS
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DOI：
10.1104/pp.89.3.823
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发表时间：
1989-03-01
期刊：
影响因子：
7.4
通讯作者：
JARRELL, WM
中科院分区：
文献类型：
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作者：
ALLAN, DL;JARRELL, WM
将描述金属氧化物表面球内络合的表面络合模型应用于4日龄和28日龄玉米（Zea mays L. cv WF9）离体细胞壁对Cu的吸附。Mo17)和21日龄大豆(Glycine max [L。)稳定。根（根）。滴定数据的浓度依赖性阻止了4天玉米细胞壁的独特pK和电容值的测定，尽管可滴定羧基的固有pK的平均值为3.0（4天玉米），3.6（28天玉米）和3.0（21天大豆），用NaOH或HCl在20毫摩尔NaCl中进行电位滴定测定。将恒电容模型应用于20毫摩尔氯化钠离子介质中快速批平衡实验的Cu吸附数据。物种形成计算表明，双齿状表面复合物的形成足以描述所有三种植物材料的实验数据，只有一个值表示pK和电容密度。中性络合Cu的固有常数为：log K = -0.3 .+-。0.1, -0.2, +-。0.3和0.9。4日龄和28日龄玉米和21日龄大豆分别为0.1。积分电容密度参数描述了表面电荷密度和电势之间的关系，它比晶体矿物表面大几倍。这一结果表明，即使表面电荷密度很高，表面电位仍然很低。这种行为是凝胶和多孔氧化物的特征。
A surface complexation model which has been used to describe inner-sphere complexation on metal oxide surfaces was applied to the adsorption of Cu by isolated cell walls of 4-day and 28-day-old maize (Zea mays L. cv WF9 .times. Mo17) and 21-day-old soybean (Glycine max [L.] Merr. cv Dare) roots. Concentration dependence of the titration data prevented the determination of unique pK and capacitance values for the 4-day maize cell walls, though mean values obtained for the intrinsic pK of the titratable carboxyl groups were 3.0 (4-day maize), 3.6 (28-day maize), and 3.0 (21-day soybean) as determined by potentiometric titration with either NaOH or HCl in 20 millimolar NaCl. The constant capacitance model was applied to Cu sorption data from rapid batch equilibrium experiments in an ionic medium of 20 millimolar NaClO4. Speciation calculations indicated that the formation of a bidentate surface complex was sufficient to describe the experimental data for all three types of plant material, with only one value for the pK and capacitance density. The intrinsic constants of Cu complexation by a neutral site are: log K = -0.3 .+-. 0.1, -0.2 .+-. 0.3, and 0.9 .+-. 0.1 for 4-day and 28-day maize, and 21-day soybean, respectively. The integral capacitance density parameter, which describes the relationship between surface charge density and electrical potential, is several times larger than for crystalline mineral surfaces. This result indicates that the surface electrical potential remains low even when the surface charge density is high. Such behavior is characteristic of gels and porous oxides.