title: Effects of humic acids on the aggregation and sorption of nano-TiO2.
abstract: In this study, humic acids (HAs) from three sources, peat, sediment and straw, used to coat nano-TiO2 were investigated. The results indicated that HAs isolated from peat were aromatic-rich, whereas those isolated from sediment and straw were aliphatic-rich. The nano-TiO2 sedimentation experiments indicated that the presence of aromatic-rich HAs was more capable of stabilizing nano-TiO2 particles than was the presence of aliphatic-rich HAs. This result is because the deionized phenolic groups in the HAs were preferentially adsorbed on the nano-TiO2 surfaces, which generated a higher charge density on the nano-TiO2 surfaces and caused stronger repulsive forces among particles. Furthermore, the aromatic-rich TiO2-HA complexes exhibited a greater sorption capacity than the aliphatic-rich TiO2-HAs complexes and nonlinear phenanthrene sorption because of their higher affinity and the condensed state of aromatic fractions. Note that natural organic matters, such as humic acids, in aquatic environments can not only increase the stability of nanoparticles but can also influence the mobility of hydrophobic organic compounds (HOCs).
authors.affiliation: College of Environment and Energy, South China University of Technology, Guangzhou, China.
authors.forename: Yanjie
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Environment and Energy, South China University of Technology, Guangzhou, China; Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, South China University of Technology, Guangzhou, China. Electronic address: cyanggz@scut.edu.cn.
authors.forename: Chen
authors.initials: C
authors.lastname: Yang
authors.affiliation: College of Environment and Energy, South China University of Technology, Guangzhou, China.
authors.forename: Xuetao
authors.initials: X
authors.lastname: Guo
authors.affiliation: College of Environment and Energy, South China University of Technology, Guangzhou, China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Dang
authors.affiliation: The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou, China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Li
authors.affiliation: School of Life and Environmental Science, Guilin University of Electronic Technology, Guilin, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D000327:Adsorption; D002851:Chromatography, High Pressure Liquid; D004785:Environmental Pollutants / Q000737:chemistry*; D052918:Environmental Restoration and Remediation; D019015:Geologic Sediments / Q000737:chemistry; D006812:Humic Substances / Q000032:analysis*; D053758:Nanoparticles / Q000737:chemistry*; D010616:Phenanthrenes / Q000737:chemistry; D006109:Poaceae / Q000737:chemistry; D012987:Soil / Q000737:chemistry; D014025:Titanium / Q000737:chemistry*
chemical_list: D004785:Environmental Pollutants; D006812:Humic Substances; D010616:Phenanthrenes; D012987:Soil; C009495:titanium dioxide; C031181:phenanthrene; D014025:Titanium
keywords: Aggregation; Humic acids; Hydrophobic organic compounds; Nanoparticles; Sorption