Removal of graphene oxide nanomaterials from aqueous media via coagulation: Effects of water chemistry and natural organic matter.
With the increasing use of graphene oxide (GO) nanomaterials, its possible environmental release and human effects have received much attention. As GO may enter drinking or wastewater treatment systems like other carbonaceous nanomaterials, and have potential impact on human and/or environmental health, its removal efficiency during water treatment is important and requires investigation. In this study, the removal efficiency of GO during water treatment procedure via coagulation was evaluated, and the effects of solution chemistry and natural organic matter on the coagulation-based removal of GO nanomaterials were investigated. The results indicate that the removal efficiency of GO with alum coagulation can reach 80% with 20 mg/L alum dosage at neutral pH, and will not change significantly with higher concentration of alum. The coagulation mechanism and efficiency were strongly affected by the Al species in aqueous phase, which are controlled by pH. Co-existing cations (e.g. Na) may have minimal effect on GO removal efficiency, and the presence of humic acid (HA) suppresses coagulation remarkably at alum concentrations below 40 mg/L. The results from this study provide critical information for predicting the removal efficiency of GO nanomaterials during alum coagulation phase of water treatment procedure.
College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin, China.
Lin
L
Duan
College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin, China.
Rongjie
R
Hao
College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin, China.
Zhu
Z
Xu
College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin, China.
Xizhen
X
He
Bren School of Environmental Science and Management, University of California, Santa Barbara, CA, 93106, United States.
Adeyemi S
AS
Adeleye
College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin, China. Electronic address: hkliyao@nankai.edu.cn.
Yao
Y
Li
D000534:Alum Compounds / Q000737:chemistry*; D005427:Flocculation; D006108:Graphite / Q000737:chemistry*; D006812:Humic Substances; D006863:Hydrogen-Ion Concentration; D049329:Nanostructures / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
D000534:Alum Compounds; D006812:Humic Substances; D010087:Oxides; D014874:Water Pollutants, Chemical; D014867:Water; C041524:aluminum sulfate; D006108:Graphite
Alum; Coagulation; Graphene oxide; Removal efficiency