欢迎访问《高校地质学报》官方网站,今天是
分享到:

高校地质学报 ›› 2021, Vol. 27 ›› Issue (4): 385-393.DOI: 10.16108/j.issn1006-7493.2020012

• 地球化学·岩石·矿床 • 上一篇    下一篇

多聚磷酸盐在羟基氢氧化铝矿物表面的吸附:基于31P 固体核磁共振技术的机制研究

李咏芳,任 超,周 强,李 伟*   

  1. 南京大学 地球科学与工程学院, 表生地球化学教育部重点实验室,南京 210023
  • 出版日期:2021-08-20 发布日期:2021-08-30

Mechanism of Poly-phosphates Sorption by Boehmite: A 31P Solid-state NMR Study

LI Yongfang,REN Chao,ZHOU Qiang,LI Wei*   

  1. Key Laboratory of Surficial Geochemistry, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China
  • Online:2021-08-20 Published:2021-08-30

摘要: 多聚磷酸盐(Poly-P)是一类非常重要的无机磷酸盐,在自然界广泛存在,研究多聚磷酸盐在自然界的迁移转化对理解磷的生物地球化学循环至关重要。矿物—溶液界面的吸附反应是控制元素在沉积物和土壤中迁移转化的一个关键过程,因此本研究选取在自然界广泛分布的勃姆石(Boehmite),即羟基氧化铝作为吸附剂,研究了勃姆石在不同初始磷浓度、不同pH条件下对多聚磷的吸附行为和吸附机制。实验结果表明:在实验条件下,随着初始磷浓度的增加,勃姆石对多聚磷的吸附量也随之增加,吸附率均接近100%;而随着pH的升高,勃姆石对多聚磷的吸附量逐渐降低。本研究进一步采用XRD、SEM、31P NMR技术对吸附产物进行了表征,核磁共振结果表明勃姆石吸附多聚磷的过程中伴随着多聚磷水解,长链中间的P-O-P键随机断裂,生成了许多短链多聚磷和正磷酸根,两者以内圈络合的形式吸附在勃姆石表面。

关键词: 多聚磷酸盐, 勃姆石, 固体核磁共振, 吸附

Abstract: Poly-Phosphate (Poly-P) is a group of very important inorganic phosphates, which exists widely in natural systems. Studying of the transport and transformation of Poly-P is critically essential to understand the biogeochemical cycling of phosphorus. Sorption reactions at mineral-solution interface control the transport and transformation of elements. In this research, the widely distributed hydrated alumina, Boehmite, was selected as the adsorbent to explore the behavior and mechanism of Poly-P sorption, as a function of initial P concentration and pH. Under the experimental conditions, the amounts of the sorbed Poly-P increase with P
concentration, whereas decrease with increasing pH. To further understand the mechanisms, we adopted several technologies, such as XRD, SEM and 31P solid-state NMR to characterize our samples. The results of 31P solid-state NMR indicate the occurrence of both adsorption and hydrolysis. The P-O-P bond in the middle of the long chain was randomly broken, generating short-chain Poly-P and orthophosphate, both of which were adsorbed as inner-sphere complexes on the surface of Boehmite.

Key words: Poly-Phosphate, Boehmite, solid-state NMR, adsorption

中图分类号: