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氢氧化钠(NaOH)和焦磷酸钠(Na4P2O7)是从陆相环境中分离腐植酸(HA)最常用的2种萃取剂。为了评价萃取剂对HA性质和微量元素的影响,采用3种不同溶液,即(a)0.5mol/LNaOH;(b)0.1mol/LNa4P2O7;(c)0.5mol/LNaOH+0.1mol/LNa4P2O7从5个泥炭藓泥炭样品中分离HA,并分析了萃取得到的HA的灰分含量、元素组成和主要原子比,以及傅立叶变换红外光谱(FT-IR)和发光光谱特征。此外,还用X射线荧光法测定泥炭样品和HA中的Br、Cu、Fe、Ni、Pb和Zn的含量。试验结果表明:用NaOH和NaOH+Na4P2O7萃取的HA在灰分、元素含量和光谱特征上十分相似,而Na4P2O7溶液通常降低了萃取率,似乎是影响了HA的本质,使之具有更加复合和芳香性的特征。与原泥炭样品比较,不论什么萃取剂萃取得到的HA,其Br、Cu和Ni含量均增加,而Fe、Pb和Zn含量减少。相比于其他的方法,用Na4P2O7萃取得到的HA含有更多Br、Cu、Ni和Zn,可能是因为HA的芳香性分子对这些元素显示出更大的亲和力。
Sodium hydroxide (NaOH) and sodium pyrophosphate (Na4P2O7) are the two most commonly used extractants for the separation of humic acid (HA) from the continental environment. To evaluate the effect of the extractant on the properties of HA and the trace elements, three different solutions were used, namely (a) 0.5 mol / L NaOH; (b) 0.1 mol / L Na4P2O7; HA were separated from peat moss peat sample, and the ash content, elemental composition and main atomic ratio of the extracted HA were analyzed, as well as the characteristics of Fourier transform infrared (FT-IR) and luminescence spectra. In addition, the contents of Br, Cu, Fe, Ni, Pb and Zn in peat samples and HA were also determined by X-ray fluorescence. The experimental results show that HA extracted with NaOH and NaOH + Na4P2O7 is very similar in ash content, elemental content and spectral characteristics, while Na4P2O7 solution usually decreases the extraction rate, which seems to affect the nature of HA and make it more complex and aromatic Characteristics. Compared with the original peat samples, the contents of Br, Cu and Ni were increased and the contents of Fe, Pb and Zn were decreased no matter what extractant extracted HA. The HA extracted with Na4P2O7 contains more Br, Cu, Ni and Zn than other methods, probably because the aromatic molecules of HA show greater affinity for these elements.