The influence of humic substances on uranium biomineralization induced by Bacillus sp. dwc-2

Publication date: February 2019

Source: Journal of Environmental Radioactivity, Volume 197

Author(s): Hong Tu, Tu Lan, Guoyuan Yuan, Changsong Zhao, Jun Liu, Feize Li, Jijun Yang, Jiali Liao, Yuanyou Yang, Dongqi Wang, Ning Liu

Abstract

In this paper, the influence of humic acid (HA) and fulvic acid (FA) on biomineralization behaviour was evaluated. The results showed HA and FA did not obviously inhabit or promote the precipitation of U-phosphate minerals. The data from molecular dynamic simulation indicated that the free energy for the dissociation of uranyl the PO₄³⁻ -uranyl was 202.49 kJ/mol, which was much larger than that form HA-uranyl (88.3 kJ/mol). These simulated results revealed the less competitiveness of HA and FA with PO₄³⁻ for uranyl and explained why HA and FA had less impacted on the formation of U-phosphate minerals. However, the influence of HA/FA on the morphology was obvious, the microstructure of the bio-minerals changed from small particles to lamellar stacking structure with the addition of HA or FA. The findings of this study are helpful for us to gain a better understanding natural U-phosphate biomineralization behaviour.

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