Configurations of lead(II)-benzohydroxamic acid complexes in colloid and interface: A new perspective

Zhao Wei; Yuehua Hu; Haisheng Han; Wei Sun

doi:10.1016/j.jcis.2019.11.115

Configurations of lead(II)-benzohydroxamic acid complexes in colloid and interface: A new perspective

J Colloid Interface Sci. 2020 Mar 7:562:342-351. doi: 10.1016/j.jcis.2019.11.115. Epub 2019 Dec 10.

Authors

Zhao Wei¹, Yuehua Hu¹, Haisheng Han², Wei Sun³

Affiliations

¹ School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Key Laboratory of Hunan Province for Clean and Efficient Utilization of Strategic Calcium-containing Mineral Resources, Central South University, Changsha 410083, China.
² School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Key Laboratory of Hunan Province for Clean and Efficient Utilization of Strategic Calcium-containing Mineral Resources, Central South University, Changsha 410083, China. Electronic address: hanhai5086@csu.edu.cn.
³ School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Key Laboratory of Hunan Province for Clean and Efficient Utilization of Strategic Calcium-containing Mineral Resources, Central South University, Changsha 410083, China. Electronic address: sunmenghu@126.com.

PMID: 31855797
DOI: 10.1016/j.jcis.2019.11.115

Abstract

Lead(II)-benzohydroxamic acid (Pb-BHA) complex collectors perform well with respect to scheelite flotation, and, due to their structure, they are widely used for industrial purposes. This paper examines the controversial issue of whether "O, O" five-membered ring or "N, O" four-membered ring complexes are formed when BHA coordinates with Pb ions, with their structure being comprehensively studied from the aspect of colloid and interface science. The configurations of Pb-BHA complexes are examined in a solution and on a mineral surface with experimental and computational methods. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) revealed that the five-membered ring is the dominant form of Pb-BHA complexes in a solution, whereas four-membered ring complexes are the stronger electron acceptor of the two. Moreover, XPS and time-of-flight secondary ion mass spectrometry (TOF-SIMS) confirmed that the four-membered ring complexes are stable with respect to being adsorbed on the scheelite surface. Therefore, although the four-membered ring is not as stable as the five-membered ring in a solution, it offers advantages with respect to adsorption on an electron-rich mineral surface during short-flotation processes.

Keywords: Benzohydroxamic acid; Configuration; DFT; TOF-SIMS; XPS.