Removal of aqueous perfluorooctanoic acid (PFOA) using starch-stabilized magnetite nanoparticles.
Fully stabilized magnetite (Fe3O4) nanoparticles were prepared with a water-soluble starch as a stabilizer and tested for removal of aqueous perfluorooctanoic acid (PFOA). The presence of starch at ≥0.2wt% can fully stabilize 0.1g/L as Fe of the Fe3O4 nanoparticles. The particle stabilization technique resulted in 2.4 times higher PFOA uptake. Fourier transform infrared spectra suggested that the main PFOA removal mechanism was inner-sphere complexation. Batch kinetic experiments revealed that the starch-stabilized nanoparticles facilitated a rapid PFOA uptake with a sorption equilibrium time of 30min, and the sorption process followed a pseudo-second-order kinetic model. The Langmuir model was able to well interpret the adsorption isotherm, with a maximum adsorption capacity of 62.5mg/g. Increasing pH from 4.7 to 9.6 led to a sharp increase (by 2.6 times) in PFOA uptake. The presence of 12mg/L humic acid inhibited PFOA uptake by 96%, while effect of ionic strength (CaCl2=0-2mmol/L) was negligible. The nanoparticles significantly reduced the biological toxicity of PFOA. The results demonstrated promise of starch-stabilized Fe3O4 nanoparticles as a "green" adsorbent for effective removal of PFOA in soil and groundwater.
College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin 300350, China; Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, Tianjin 300350, China.
Yanyan
Y
Gong
College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
Lin
L
Wang
College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
Juncheng
J
Liu
College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin 300350, China; Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, Tianjin 300350, China. Electronic address: tangjch@nankai.edu.cn.
Jingchun
J
Tang
Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849, USA. Electronic address: zhaodon@auburn.edu.
Dongye
D
Zhao
Adsorption; Emerging contaminants; Groundwater remediation; Magnetite nanoparticles; Perfluorooctanoic acid