title: Environmental application of millimetre-scale sponge iron (s-Fe⁰) particles (I): pretreatment of cationic triphenylmethane dyes.
abstract: To investigate the removal capability of millimetric zero valent iron (mmZVI), sponge iron (s-Fe(0)) particles were characterized with XRD, XPS, TEM, HRSEM and EDS techniques. Moreover, the roles of particle size, catalyst dosage, dye concentration, mixing conditions (e.g. ultrasound (US), stirring or shaking), and regeneration treatment were studied with the removal of cationic triphenylmethane dyes. Notably, the reduction process was also revealed as compared to nanoscale zero valent iron (nZVI), microscale iron power, and iron scurf. Furthermore, the reductive mechanism was exemplified with brilliant green. The results demonstrated that (1) the synergetic effect between US and s-Fe(0) greatly enhanced the removal of dyes, (2) the dosage of preferred s-Fe(0) (1-3mm) particles was optimized as 30.0g/L; (3) reuse cycles of s-Fe(0) catalyst were enhanced with the assistance of diluted HCl solution; (4) the main degradation routes included the cleavage of conjugated structure reactions, N-de-ethylation reactions, hydroxylation reactions, the removal of benzene ring reactions, and opening ring reactions. Accordingly, the pretreatment of aqueous solution over s-Fe(0) was hypothesized to achieve mainly through direct reduction reaction by electron transfer and indirect reductive reactions by the highly activated hydrogen atom. Additionally, decoration with noble metals was utilized to reveal the reaction mechanism.
authors.affiliation: South China Institute of Environmental Sciences, the Ministry of Environmental Protection of PRC, Guangzhou 510655, PR China. Electronic address: juyongming@scies.org.
authors.forename: Yongming
authors.initials: Y
authors.lastname: Ju
authors.affiliation: South China Institute of Environmental Sciences, the Ministry of Environmental Protection of PRC, Guangzhou 510655, PR China. Electronic address: liuxiaowen@scies.org.
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Liu
authors.affiliation: South China Institute of Environmental Sciences, the Ministry of Environmental Protection of PRC, Guangzhou 510655, PR China.
authors.forename: Zhaoyong
authors.initials: Z
authors.lastname: Li
authors.affiliation: South China Institute of Environmental Sciences, the Ministry of Environmental Protection of PRC, Guangzhou 510655, PR China.
authors.forename: Juan
authors.initials: J
authors.lastname: Kang
authors.affiliation: South China Institute of Environmental Sciences, the Ministry of Environmental Protection of PRC, Guangzhou 510655, PR China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Wang
authors.affiliation: South China Institute of Environmental Sciences, the Ministry of Environmental Protection of PRC, Guangzhou 510655, PR China.
authors.forename: Yukui
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: South China Institute of Environmental Sciences, the Ministry of Environmental Protection of PRC, Guangzhou 510655, PR China.
authors.forename: Jiande
authors.initials: J
authors.lastname: Fang
authors.affiliation: Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012, USA. Electronic address: dionysios.d.dionysiou@uc.edu.
authors.forename: Dionysios D
authors.initials: DD
authors.lastname: Dionysiou
mesh_terms: D004396:Coloring Agents / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D010316:Particle Size; D014320:Triphenylmethyl Compounds / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D014320:Triphenylmethyl Compounds; D014874:Water Pollutants, Chemical; C046945:triphenylmethane; D007501:Iron
keywords: Mechanism; Millimetric zero valent iron (mmZVI); Sponge iron (s-Fe(0)); Textile wastewater; Triphenylmethane dyes