| 摘要: |
| Mehlich法和电位滴定法研究表明,供试土壤胶体可变电荷量占总电荷量(CECv/ CEC8.2)的比例为33.64%～35.58%;表面电荷量 CECCEC8.2 ,CECp和CECv 的大小次序为塿土>黄绵土>黑垆土>黄褐土;电荷零点(PZC)大小与此顺序相反 ;同一土壤胶体其PZC大小呈 Ca(NO3)2>KCl>NaNO3的趋势 ,在 Na2SO4介质中不存在PZC。各土壤胶体负电荷密度随pH增加的幅度即为pH对土壤胶体表面电荷密度的贡献率(简称为pH贡献率),增加的幅度愈大,表明pH对表面负电荷密度的贡献率愈大。pH贡献率的大小呈黄绵土>黑垆土>塿土>黄褐土的趋势;同一土壤胶体,pH的贡献率基本上呈现 KCl>Na2SO4>Ca(NO3)2>NaNO3。 |
| 关键词: 恒电荷土壤胶体 电荷零点 电位滴定 电荷密度 |
| DOI： |
| 分类号:S858.315.3 |
| 基金项目:国家自然科学基金资助项目(79770074) |
|
| Charge characteristics of constant charge soil colloids |
|
YUAN Xiao ling 1 YUAN Xiao qun 2
|
| Abstract: |
| Mehlich and potentiometric titration methods showed that specific value of varible negative charge to total negative charge (CECv/ CEC8.2) was between 33.64% to 35.58%,the sequence of CECCEC8.2 ,CECp and CECv was:old manured loessal soil>yellow loessal soil>dark cultivated loessal soil>yellow cinamon soil,the sequence of PZC was opposition with negative charge.In different eletrolytes,PZC of same soil colloid showed the trend of Ca(NO3)2>KCl>NaNO3.The increasing slope of negative charge density with pH increasing was expressed with the pH contribution rate,the pH contribution rate of different soil colloids showed in the sequence that yellow loessal soil>dark cultivated loessal soil>old manured loessal soil>yellow cinamon soil,in different eletrolytes,pH contribution rate of same soil colloid showed the trend of KCl>Na2SO4>Ca(NO3)2>NaNO3. |
| Key words: constant charge soil colloid the point of zero charge potentiometric titration charge density |
