title: Cake properties in ultrafiltration of TiO2 fine particles combined with HA: in situ measurement of cake thickness by fluid dynamic gauging and CFD calculation of imposed shear stress for cake controlling.
abstract: In this study, the cake buildup of TiO2 fine particles in the presence of humid acid (HA) and cake layer controlling during ultrafiltration (UF) were investigated. Specifically, we measured the cake thickness using fluid dynamic gauging (FDG) method under various solution conditions, including TiO2 concentration (0.1-0.5 g/L), HA concentration (0-5 mg/L, total organic carbon (TOC)), and pH values (e.g., 4, 6 and 10), and calculated the shear stress distribution induced by stirring using computational fluid dynamics (CFD) to analyze the cake layer controlling conditions, including the operation flux (50-200 L m(-2) h(-1)) and TiO2 concentration (0.1-0.5 g/L). It was found that lower TiO2/HA concentration ratio could lead to exceedingly severe membrane fouling because of the formation of a relatively denser cake layer by filling the voids of cake layer with HA, and pH was essential for cake layer formation owing to the net repulsion between particles. Additionally, it was observed that shear stress was rewarding for mitigating cake growth under lower operation flux as a result of sufficient back-transport forces, and exhibited an excellent performance on cake layer controlling in lower TiO2 concentrations due to slight interaction forces on the vicinity of membrane.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, People's Republic of China.
authors.forename: Xing
authors.initials: X
authors.lastname: Du
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, People's Republic of China.
authors.forename: Fangshu
authors.initials: F
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, People's Republic of China. hitliangheng@163.com.
authors.forename: Heng
authors.initials: H
authors.lastname: Liang
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, 13 Yanta Road, Xi'an, 710055, People's Republic of China.
authors.forename: Kai
authors.initials: K
authors.lastname: Li
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, People's Republic of China.
authors.forename: Haiqing
authors.initials: H
authors.lastname: Chang
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, People's Republic of China.
authors.forename: Guibai
authors.initials: G
authors.lastname: Li
mesh_terms: D005374:Filtration / Q000295:instrumentation; D006812:Humic Substances / Q000032:analysis*; D057446:Hydrodynamics; D007287:Inorganic Chemicals; D008567:Membranes, Artificial; D014025:Titanium / Q000032:analysis / Q000737:chemistry*; D014462:Ultrafiltration / Q000379:methods*; D014865:Waste Disposal, Fluid
chemical_list: D006812:Humic Substances; D007287:Inorganic Chemicals; D008567:Membranes, Artificial; C009495:titanium dioxide; D014025:Titanium
keywords: CFD; Cake buildup; Cake controlling; FDG; Shear stress; UF
references.citation: Adv Colloid Interface Sci. 2011 May 11;164(1-2):38-44
references.pmid: 21353191
references.citation: Chemosphere. 2015 Jan;119:171-6
references.pmid: 24992218
references.citation: Adv Colloid Interface Sci. 2015 Aug;222:332-49
references.pmid: 25150615
references.citation: Water Res. 2010 May;44(10):2997-3027
references.pmid: 20378145
references.citation: Environ Sci Technol. 2006 Apr 15;40(8):2699-705
references.pmid: 16683611
references.citation: Bioresour Technol. 2011 Dec;102(24):11121-31
references.pmid: 22014502
references.citation: J Hazard Mater. 2011 Dec 15;197:70-9
references.pmid: 22001572
references.citation: Water Res. 2012 May 15;46(8):2535-44
references.pmid: 22386328
references.citation: Environ Sci Technol. 2010 Sep 1;44(17 ):6532-49
references.pmid: 20687602
references.citation: Water Res. 2013 Oct 15;47(16):6052-63
references.pmid: 23969399
references.citation: Nature. 2001 Jun 14;411(6839):772-5
references.pmid: 11459050
references.citation: Water Res. 2008 Aug;42(14):3870-8
references.pmid: 18715606
references.citation: Water Res. 2015 May 15;75:131-45
references.pmid: 25768986