title: Chlorinated Methylsiloxanes Generated in the Papermaking Process and Their Fate in Wastewater Treatment Processes.
abstract: Simulated experiments indicated that chlorinated volatile methylsiloxanes, detected by Q-TOF GC/MS, could be generated in a pulp-bleaching process, where poly(dimethylsiloxane)s fluids with volatile methylsiloxanes as impurities and molecular chlorine were used as a defoamer and bleaching agent, respectively. In the producing processes of one papermaking factory, the mean total concentrations of monochlorinated D4, D5, and D6, i.e., D3D(CH2Cl), D4D(CH2Cl), and D5D(CH2Cl), were 0.0430-287 μg/L in aqueous samples, while they were 0.0329-270 μg/g in solid samples. In the coupled papermaking-wastewater treatment processes, D3D(CH2Cl), D4D(CH2Cl), and D5D(CH2Cl) were detected in all water (0.113-8.68 μg/L) and solid samples (0.888-26.2 μg/g), with solid-water partition values (468-3982 L/kg) 1.08-4.82 times higher than those of their corresponding nonchlorinated analogs. The removing efficiencies of D3D(CH2Cl)-D5D(CH2Cl) in the whole wastewater treatment processes were 77.1-81.6%, and sorption to sludge (35.7-74.1%) and removal in the primary clarifier (7.19-32.5%) had major contributions to their total removal. Elimination experiments showed that 1) hydrolysis half-lives of D3D(CH2Cl)-D5D(CH2Cl) (0.9-346 h) in the primary clarifier (pH = 7.8-9.2) were 2.16-3.60 times shorter than those of their nonchlorinated analogs; 2) D3D(CH2Cl)-D5D(CH2Cl) were hardly degraded in oxic sludge treatment process, and their volatilization half-lives (7.38-21.1 h) in oxic sludge were 1.21-1.50 times longer than those of their nonchlorinated analogs.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Xu
authors.affiliation: School of Chemical & Environmental Engineering, China University of Mining & Technology (Beijing) , Beijing 100083, China.
authors.forename: Xudan
authors.initials: X
authors.lastname: He
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.
authors.forename: Liqin
authors.initials: L
authors.lastname: Zhi
authors.affiliation: School of Chemical & Environmental Engineering, China University of Mining & Technology (Beijing) , Beijing 100083, China.
authors.forename: Chunhui
authors.initials: C
authors.lastname: Zhang
authors.affiliation: College of Environment, Zhejiang University of Technology , Hangzhou 310032, P. R. China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.|Institute of Environment and Health, Jianghan University , Wuhan 430056, China.
authors.forename: Yaqi
authors.initials: Y
authors.lastname: Cai
mesh_terms: D012722:Sewage / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry; D014835:Volatilization; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical
chemical_list: D012722:Sewage; D012833:Siloxanes; D062065:Wastewater; D014874:Water Pollutants, Chemical