Sorption of atrazine onto humic acids (HAs) coated nanoparticles

College of Materials Science and Technology, Beijing Forestry University, Beijing 100083, China
Colloids and Surfaces A Physicochemical and Engineering Aspects (Impact Factor: 2.75). 09/2009; 347(1):90-96. DOI: 10.1016/j.colsurfa.2008.12.032


With the development of nanotechnologies, a large number of nano-materials with novel properties are being released into the environment. However, little is known about their fate, transport, toxicity and interactions with organic matters in aqueous environment. In this study, nano-SiO2 or kaolinite, coated with soil humic acid (SHA) and peat humic acid (PHA), were used as sorbents. The original and HA-coated nanoparticles were characterized for particle size, TEM and electrophoretic mobility. Sequential ultrafiltration (UF) was used to characterize the molecular size fractionations of dissolved HAs. Sorption data of atrazine (AT) under various solution concentration, ionic strength and pH were well fitted with Freundlich model. Sorption amount of AT on HA-coated nanoparticles was significantly lower than that on original particles. The sorption maximum appeared at I = 0.001 mol/l (NaNO3), pH 3. Size of nanoparticle aggregates, conformation of HA and specific surface area were factors affecting the sorption process. The compressed conformation of HA was more favorable for HA sorption than expanded one. Size of aggregation was not a determinant factor for the sorption process, while the specific surface areas of nano-sorbent was an important one. Results indicated that HA plays an important role in the transport and toxicity of nanoparticles and AT in aqueous environment.

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    • "Humic substances are structurally complex large to macromolecules which occur in soils and natural waters as a consequence of the breakdown of plant and animal residues by microbial activity (Jones, 1998). Aquatic humic substances are a category of the most widely distributed organic matters that constitute 30–50% of dissolved organic matter (DOM) in natural aquatic systems (Lu et al., 2009). Humic acid is ubiquitous in the environment and has been found to influence physiological functions of aquatic organisms (Andersson et al., 2010). "
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    • "cts might occur independently or in combination , so it is difficult to predict their net effect on contaminant degradation kinetics ( Tratnyek et al . , 2001 ) . However , limited studies have reported the effects of NOM on the decomposition of some other contaminants by Fe 0 ( Tratnyek et al . , 2001 ; Zhang et al . , 2009 ; Rao et al . , 2009 ; Lu et al . , 2009 ; Giasuddin et al . , 2007 ) . Zhang et al . ( 2009 ) found the introduction of HA de - creased the removal of 2 , 4 - DCP . Rao et al . ( 2009 ) reported that the removal rate of arsenic by Fe 0 was inhibited in the presence of HA probably because of the formation of soluble Fe - humate in the groundwater which hindered the formation o"
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