title: Biorecovery of gold as nanoparticles and its catalytic activities for p-nitrophenol degradation.
abstract: Recovery of gold from aqueous solution using simple and economical methodologies is highly desirable. In this work, recovery of gold as gold nanoparticles (AuNPs) by Shewanella haliotis with sodium lactate as electron donor was explored. The results showed that the process was affected by the concentration of biomass, sodium lactate, and initial gold ions as well as pH value. Specifically, the presence of sodium lactate determines the formation of nanoparticles, biomass, and AuCl4 (-) concentration mainly affected the size and dispersity of the products, reaction pH greatly affected the recovery efficiency, and morphology of the products in the recovery process. Under appropriate conditions (5.25 g/L biomass, 40 mM sodium lactate, 0.5 mM AuCl4 (-), and pH of 5), the recovery efficiency was almost 99 %, and the recovered AuNPs were mainly spherical with size range of 10-30 nm (~85 %). Meanwhile, Fourier transforms infrared spectroscopy and X-ray photoelectron spectroscopy demonstrated that carboxyl and amine groups might play an important role in the process. In addition, the catalytic activity of the AuNPs recovered under various conditions was testified by analyzing the reduction rate of p-nitrophenol by borohydride. The biorecovered AuNPs exhibited interesting size and shape-dependent catalytic activity, of which the spherical particle with smaller size showed the highest catalytic reduction activity with rate constant of 0.665 min(-1).
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou, 510006, People's Republic of China. nwzhu@scut.edu.cn.|The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education, Guangzhou, 510006, People's Republic of China. nwzhu@scut.edu.cn.|Guangdong Environmental Protection Key Laboratory of Solid Waste Treatment and Recycling, Guangzhou, 510006, People's Republic of China. nwzhu@scut.edu.cn.
authors.forename: Nengwu
authors.initials: N
authors.lastname: Zhu
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou, 510006, People's Republic of China.
authors.forename: Yanlan
authors.initials: Y
authors.lastname: Cao
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou, 510006, People's Republic of China.
authors.forename: Chaohong
authors.initials: C
authors.lastname: Shi
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou, 510006, People's Republic of China.|The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education, Guangzhou, 510006, People's Republic of China.|Guangdong Environmental Protection Key Laboratory of Solid Waste Treatment and Recycling, Guangzhou, 510006, People's Republic of China.
authors.forename: Pingxiao
authors.initials: P
authors.lastname: Wu
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou, 510006, People's Republic of China.
authors.forename: Haiqin
authors.initials: H
authors.lastname: Ma
mesh_terms: D001894:Borohydrides / Q000737:chemistry; D002384:Catalysis; D006046:Gold / Q000032:analysis / Q000737:chemistry; D053768:Metal Nanoparticles / Q000032:analysis / Q000737:chemistry; D009596:Nitrophenols / Q000737:chemistry*
chemical_list: D001894:Borohydrides; D009596:Nitrophenols; D006046:Gold; C024836:4-nitrophenol
keywords: Biorecovery; Catalyst; Gold nanoparticles; Shewanella haliotis; Sodium lactate; p-Nitrophenol