title: Research on magnetic separation for complex nickel deep removal and magnetic seed recycling.
abstract: This study investigated the deep removal of complex nickel from simulated wastewater using magnetic separation and magnetic seed recycling. Nano-magnetite (Fe3O4) was used as the magnetic seed. The flocculant applied was N,N-bis-(dithiocarboxy) ethanediamine (EDTC), a highly efficient heavy metal chelating agent included in dithiocarbamate (DTC). Important investigated parameters included hydraulic retention time, magnetic seed dosage, and magnetic field strength. The study also explored the magnetic flocculation mechanism involved in the reaction. The result indicated that the residual Ni concentration was reduced to less than 0.1 mg/L from the initial concentration of 50 mg/L under optimal conditions. Magnetic seed recovery reached 76.42% after a 3-h stirring period; recycled magnetic seeds were analyzed using scanning electron microscope (SEM) and X-ray diffraction (XRD). The zeta potential results illustrated that magnetic seeds firmly combined with flocs when the pH ranged from 6.5 to 7.5 due to the electrostatic attraction. When the pH was less than 7, magnetic seeds and EDTC were also combined due to electrostatic attraction. Particle size did affect microfloc size; it decreased microfloc size and increased floc volume through magnetic seed loading. The effective binding sites between flocs and magnetic seeds increased when adding the magnetic seeds. This led the majority of magnetic flocs to be integrated with the magnetic seeds, which served as a nucleus to enhance the flocculation property and ultimately improve the nickel complex removal rate.
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China.|Key Laboratory of Mining and Metallurgy Industry Heavy Metals Pollution Control and Vocational Education of Environmental Protection of Guangdong Province, Guangzhou, 510006, People's Republic of China.
authors.forename: Yiqin
authors.initials: Y
authors.lastname: Qiu
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China.|Key Laboratory of Mining and Metallurgy Industry Heavy Metals Pollution Control and Vocational Education of Environmental Protection of Guangdong Province, Guangzhou, 510006, People's Republic of China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Xiao
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China.|Key Laboratory of Mining and Metallurgy Industry Heavy Metals Pollution Control and Vocational Education of Environmental Protection of Guangdong Province, Guangzhou, 510006, People's Republic of China.
authors.forename: Ziwei
authors.initials: Z
authors.lastname: Ye
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China.|Key Laboratory of Mining and Metallurgy Industry Heavy Metals Pollution Control and Vocational Education of Environmental Protection of Guangdong Province, Guangzhou, 510006, People's Republic of China.
authors.forename: Zhijie
authors.initials: Z
authors.lastname: Guan
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China. sysun@gdut.edu.cn.|Key Laboratory of Mining and Metallurgy Industry Heavy Metals Pollution Control and Vocational Education of Environmental Protection of Guangdong Province, Guangzhou, 510006, People's Republic of China. sysun@gdut.edu.cn.|Guangdong Polytechnic of Environmental Protection Engineering, Foshan, 528216, People's Republic of China. sysun@gdut.edu.cn.
authors.forename: Shuiyu
authors.initials: S
authors.lastname: Sun
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China.|Key Laboratory of Mining and Metallurgy Industry Heavy Metals Pollution Control and Vocational Education of Environmental Protection of Guangdong Province, Guangzhou, 510006, People's Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Ren
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China.|Key Laboratory of Mining and Metallurgy Industry Heavy Metals Pollution Control and Vocational Education of Environmental Protection of Guangdong Province, Guangzhou, 510006, People's Republic of China.
authors.forename: Pingfan
authors.initials: P
authors.lastname: Yan
mesh_terms: D005427:Flocculation; D008280:Magnetics; D009532:Nickel; D059027:Recycling; D014961:X-Ray Diffraction
chemical_list: D009532:Nickel
keywords: Complex nickel; EDTC; Electroplating wastewater; Magnetic seed recycle; Magnetic separation; Nano-magnetite