摘要
石英对Cu2+、Pb2+、Zn2+、Cd2+、和Ni2+等二价重金属离子的吸附等温线研究表明，石英对重金属离子的吸附反应可用Freudlich方程很好地进行描述，拟合曲线相关系数（r）＞0.96；吸附反应以形成金属离子单配位形态为主，只是Cu2+、Zn2+和Ni2+等三种离子有一部分双配位形态生成。同时，利用表面配位理论模式对实验结果进行拟合，其结果为表观表面配位常数lgKM=2.2—3.3，且KCd≥KPb＞KZn＞KNi≥KCu；lgβM=5.9－6.8，且βNi＞βZn＞βCu。可见，离子对石英表面的亲合力强度大小顺序是Cd＞Pb＞Zn＞Ni＞Cu。表现表面配位常数的大小主要由离子玻恩水化系数（△Ωr，v）决定，但受离子水解常数的影响。
Adsorption of divalent metal ions, including Cu2+, Pb2+, Zn2+, Cd2+ and Ni2+,onto quartz was measured as a function of metal ion concentration at 30℃ under conditions of pH = 6.5 and I = 0.1mol / L. The experimental measurements can be described very well by adsorption isotherm equations of Freudlich. The correlation coefficient of adsorption isotherm lines (r) is > 0.96. Moreover, the experimental data were interpreted on the basis of surface complexation model. It shows that the monodentate-coordinted metal ion surface complexes species (SOM+) are predominant over the bidentate-coordinted metal ion surface complexes species ((SO)2M). The later formed in little only by ions of Cu2+, Zn2+, and Ni2 +. The results simulated simplifiedly by surface complexion model are as follows : The apparent surface complexation constants lgKM = 2.2-3.3, and KCd≥KZn > KNi≥KCu; lgβM=5.9- 6.8, and βNi > βZn >βCu. The ability on reactivity of ions to quartz folllows the sequenced:Cd > Pb > Zn > Ni > Cu. The Born solvation Gibbs free energy is the major factor controlling the surface complexation of metal ions, therefore, the apparent surface complexation constants depend on the Born solvation coefficient.
出处
《地球化学》
CAS
CSCD
北大核心
1998年第6期521-531,共11页
Geochimica
基金
国家自然科学基金!49572091
关键词
石英
重金属离子
吸附
表面反应
实验研究
quartz, heavy metal ion, adsorption, apparent surface complexation constants
