亚临界水处理模拟有机-矿质复合体形成机制探讨  

Formation mechanism of organic-mineral complexes simulated by subcritical water treatment method

作　　者：王菲[1] 何江涛[1] 何宝南 

机构地区：[1]中国地质大学(北京)水资源与环境工程北京市重点实验室,北京100083

出　　处：《中国环境科学》2016年第8期2495-2504,共10页China Environmental Science

基　　金：中央高校基本科研业务费项目(35832015023)

摘　　要：为模拟地质吸附剂中的有机质矿化腐殖化及有机-矿质复合体的形成过程,采用亚临界水处理技术,通过控制压力反应釜的温度、压力和反应时间对商用腐殖酸、高岭土及有机-矿质复合体进行处理,并通过比表面积全分析、傅里叶红外光谱(FTIR)、特定波长可见吸光度比值(E_4/E_6)、X射线衍射(XRD)和^(13)C核磁共振(^(13)C-NMR)等表征手段尝试探讨不同处理条件下有机质、粘土矿物及二者复合体的各自变化特征及机制.结果表明,升温增压不仅导致腐殖酸比表面积显著增加,而且分子量变大,芳化度由59.52%增加到70.90%,其主要原因是游离羧基和链烃在升温增压条件下实现了成环、聚合过程,使其结构更加复杂,化学稳定性提高.高岭土在升温增压的过程中脱水,形成结晶更加完整的有序结构.腐殖酸与高岭土形成有机-矿质复合体的过程中存在多重作用,首先高岭土优先选择腐殖酸分子中的芳香组分进行插层,至形成较为致密的内层结构,其次,补丁在外围的游离羧基、烷氧和链式结构在高温高压的作用下成环、聚合形成疏松的外层空间.高岭土、腐殖酸及二者的复合体的变化趋势分别与天然环境中粘土矿物及有机质的矿化腐殖化进程和方向相一致.Humification of organic matter and formation of organic-mineral complexes were simulated with subcritical water treatment method. A series of samples containing commercial humic acid, kaolin, and organic-mineral complexes were prepared under designed temperature, pressure and reaction time, respectively, in a high-temperature and high-pressure reaction kettle. Changing characteristic and mechanism of these samples under different conditions were investigated by means of specific surface area analysis （SSA）, Fourier infrared spectrum （FTIR）, particular wavelength absorbance ratio （E4/E6）, X-ray diffraction （XRD） and 13C nuclear magnetic resonance （13C-NMR）. The results showed that SSA, molecular weight, and degree of aromatization （from 59.52% to 70.90%） of humic acids increased significantly with increasing temperature and pressure. This was caused by the cyclization and polymerization of free carboxyl and chain hydrocarbon in humic acid, which led to a more complicated structure and an improvement of chemical stability of humic acids. Increasing temperature and pressure resulted in dehydration and a complete and orderly structure of kaolin. There were several interactions involved in the formation of organic-mineral complexes. At first, aromatic components of humic acid intercalated into kaolin and caused a relatively dense inner structure. Then, the cyclized and polymerized free carboxyl, alkanes and chain structures patched loosely on the kaolin and formed the outer space. The change trend of humic acid, kaolin and their complexes in the experiments was consistent with the direction of mineralization and humification of these substances in nature.

关 键 词：腐殖酸 高岭土 有机-矿质复合体 亚临界水处理方法 

分 类 号：X523[环境科学与工程—环境工程]