褐土碳酸钙结核的胶体特性研究  

Colloid Properties of Calcium Carbonate Nodules in Cinnamon Soil

作　　者：胡宁 许晨阳[1,2] 耿增超 胡斐南[3,4] 马璐璐 HU Ning;XU Chenyang;GENG Zengchao;Hu Feinan;MA Lulu(College of Natural Resources and Environment,Northwest A&F University,Yangling,Shaanxi 712100,China;Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China,Ministry of Agriculture,Northwest A&F University,Yangling,Shaanxi 712100,China;State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau,Northwest A&F University,Yangling,Shaanxi 712100,China;Institute of Soil and Water Conservation,Chinese Academy of Sciences&Ministry of Water Resources,Yangling,Shaanxi 712100,China)

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100 [2]西北农林科技大学农业部西北植物营养与农业环境重点实验室,陕西杨凌712100 [3]西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100 [4]中国科学院水利部水土保持研究所,陕西杨凌712100

出　　处：《土壤》2022年第5期1000-1009,共10页Soils

基　　金：国家自然科学基金项目(41701261);中央高校基本科研业务费(2452020165)资助。

摘　　要：碳酸钙是黄土母质发育土壤的重要胶结物质,对土壤团粒结构的形成具有重要作用。本文采集了碳酸盐褐土中的碳酸钙结核,采用物理分散法和化学分散法分别提取得到褐土碳酸钙结核纳米颗粒和褐土碳酸钙结核胶体,并以工业纳米碳酸钙作为对照对其胶体特性进行研究。采用X射线衍射仪、zeta电位仪和动态光散射仪对褐土碳酸钙结核胶体和工业纳米碳酸钙的矿物组成、zeta电位和胶体稳定性进行了表征。结果表明:褐土碳酸钙结核胶体、褐土碳酸钙结核纳米颗粒和工业纳米碳酸钙的初始颗粒直径分别为224.24、88.01和98.50nm,而褐土碳酸钙结核胶体和褐土碳酸钙结核纳米颗粒的多分散度高于工业纳米碳酸钙。褐土碳酸钙结核胶体中方解石含量为70.3%,其次含有石英、长石和伊利石等矿物;褐土碳酸钙结核纳米颗粒主要含有方解石和伊利石,含量分别为48%和45%。3种碳酸钙胶体表面均带负电荷,其zeta电位绝对值均随着溶液pH的增大而增大。褐土碳酸钙结核胶体在NaCl和CaCl_(2)溶液中的临界聚沉浓度分别为538.01mmol/L和2.08mmol/L,褐土碳酸钙结核纳米颗粒在NaCl和CaCl溶液中的临界聚沉浓度为82.18 mmol/L和1.11 mmol/L,而工业纳米碳酸钙的临界聚沉浓度为80.37 mmol/L和1.59 mmol/L。3种碳酸钙胶体的矿物组成差异是引发其凝聚行为差别的内在原因,化学分散剂的表面修饰作用、颗粒直径大小和溶液化学条件也是影响胶体稳定性的重要因素。本文研究结果表明,碳酸钙胶体的可变电荷特性可能是其具有胶结特性的本质原因,其对石灰性土壤团聚体结构的影响还需要进一步深入研究。Calcium carbonate is an important cementing agent of soils developed from loess,and it plays a crucial role in the formation of soil granular structure.In this paper,calcium carbonate nodules(CCN)were collected from carbonate cinnamon soil.CCN colloids and nanoparticles were obtained through physical extraction method and chemical dispersion method,respectively.Their colloidal properties were investigated by taking the artificial nano-calcium carbonate as contrast.The mineral composition,zeta potential and colloidal stability of soil CCN colloids and artificial nano-calcium carbonate(NCC)were characterized by X-ray diffractometer,zeta potential analyzer and dynamic light scattering apparatus,respectively.The results showed that the initial particle diameters of CCN colloids,nanoparticles and artificial NCC were 224.24,88.01 and 98.50 nm,respectively.However,the polydispersity of CCN colloids and nanoparticles were higher than that of artificial NCC.The content of calcite in CCN colloids was 70.3%,followed by quartz,feldspar and illite,and the contents of calcite and illite in CCN nanoparticles were 48%and 45%,respectively.The testing calcium carbonate colloids were all negatively-charged,and the absolute values of zeta potential was increased with increasing solution pH.The critical coagulation concentrations of CCN colloids in NaCl and CaClsolutions were 538.01 mmol/L and 2.08 mmol/L,respectively.The critical coagulation concentrations of CCN nanoparticles in NaCl and CaCl_(2) solutions were 82.18 mmol/L and 1.11 mmol/L,respectively.Moreover,the critical coagulation concentrations of artificial NCC were 80.37 mmol/L and 1.59 mmol/L,respectively.The differences in mineral composition of the three calcium carbonate colloids were the intrinsic reason for the discrepancy in their aggregation behaviors.The addition of chemical dispersant,initial particle diameter and solution conditions were also important factors influencing colloidal stability.The present study showed that the variable charges of calcium carbonate

关 键 词：碳酸钙结核 表面电荷 临界聚沉浓度 胶体稳定性 

分 类 号：S153.3[农业科学—土壤学]