Activation of persulfates by natural magnetic pyrrhotite for water disinfection: Efficiency, mechanisms, and stability.
This study introduces natural occurring magnetic pyrrhotite (NP) as an environmentally friendly, easy available, and cost-effective alternative catalyst to activate persulfate (PS) of controlling microbial water contaminants. The E. coli K-12 inactivation kinetics observed in batch experiments was well described with first-order reaction. The optimum inactivation rate (k = 0.47 log/min) attained at a NP dose of 1 g/L and a PS dose of 1 mM, corresponding to total inactivation of 7 log10cfu/mL cells within 15 min. Measured k increased > 2-fold when temperature increased from 20 to 50 °C; and > 4-fold when pH decreased from 9 to 3. Aerobic conditions were more beneficial to cell inactivation than anaerobic conditions due to more reactive oxygen species (ROS) generated. ROS responsible for the inactivation were identified to be SO4-> OH > H2O2based on a positive scavenging test and in situ ROS determination. In situ characterization suggested that PS effectively bind to NP surface was likely to form charge transfer complex (≡Fe(II)⋯O3SOOSO3-), which mediated ROS generation and E. coli K-12 oxidation. The increased cell-envelope lesions consequently aggravated intracellular protein depletion and genome damage to cause definite bacterial death. The NP still maintained good physiochemical structure and stable activity even after 4 cycle. Moreover, NP/PS system also exhibited good E. coli K-12 inactivation efficiency in authentic water matrices like surface water and effluents of secondary wastewater.
School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China.
Dehua
D
Xia
The Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing, 100871, China.
Yan
Y
Li
School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China.
Guocheng
G
Huang
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China.
Ran
R
Yin
Institute of Environmental Health and Pollution Control, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, Guangdong, China. Electronic address: antc99@gdut.edu.cn.
Taicheng
T
An
Institute of Environmental Health and Pollution Control, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, Guangdong, China.
Guiying
G
Li
Centre for Clean Environment and Energy, Griffith Scholl of Environment, Griffith University, Queensland, 4222, Australia; Laboratory of Nanomaterials and Nanostructures, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei, 230031, Anhui, China.
Huijun
H
Zhao
School of Geoscience and Info-Physics, Central South University, Changsha, 410083, China.
Anhuai
A
Lu
School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China. Electronic address: pkwong@cuhk.edu.hk.
Po Keung
PK
Wong
D004203:Disinfection; D004926:Escherichia coli / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D014867:Water / Q000378:metabolism; D018508:Water Purification
D014867:Water; D006861:Hydrogen Peroxide
Heterogeneous catalysis; Natural pyrrhotite; Persulfate; Sulfate radical; Water disinfection