Roles of extracellular polymeric substances in uranium immobilization by anaerobic sludge

Hai-Ling Zhang,Meng-Xi Cheng,Huan-Huan Ding,Dong Zhao,He-Xiang Huang,Yong-Peng Wang,Shi-Cheng Li,Xian-Jin Lyu,Feng-Yu Huang,Wei-Dong Liu,Jian Chu

doi:10.1186/s13568-019-0922-2

Abstract

The specific roles of extracellular polymeric substances (EPS) and how factors influenced EPS’s roles during U(VI) immobilization are still unclear. In this study, high content of U with the main form of nanoparticles was detected in EPS, accounting for 10–42% of total U(VI) removal. EPS might be utilized as energy source or even as electron donors when external carbon source was unavailable. The influencing degree of each experimental parameter to uranium (U) removal process was elucidated. The influential priority to U(IV)/U(VI) ratios in sludge was as follows: acetate, U(VI), and nitrate. The influential priority to total EPS contents was as follows: U(VI), nitrate and acetate. The complex interaction mechanism between U(VI) and EPS in the U immobilization process was proposed, which might involve three ways including biosorption, bioreduction and bioprecipitation. These results indicate important and various roles of EPS in U(VI) immobilization.

Highlights

Uranium (U) pollution is an issue of global concern due to its high toxicity and radioactivity
One-way analysis of variance (ANOVA) method was applied to distinguish whether significant difference existed between/among results obtained by only changing the specific parameter
The influential priority of various environmental parameters was evaluated using grey relational analysis (GRA) method with grey relational grades γ as the quantitative index. Both ANOVA and GRA were performed by Microsoft excel

Summary

Introduction

Uranium (U) pollution is an issue of global concern due to its high toxicity and radioactivity. Single particle inductively coupled plasma-mass spectrometry (ICP-MS) offers an efficient tool to identify the U species in solution (Degueldre et al 2006; Zhang et al 2017). It can distinguish the U in soluble and particulate forms, and reveal size distribution information of the U particles. Using this technique, more detailed information about the roles of EPS in U removal by anaerobic sludge system could be obtained

Objectives

Methods

Results

Conclusion