Aggregation kinetics of CeO2 nanoparticles in KCl and CaCl2 solutions: measurements and modeling

Li, Kungang; Zhang, Wen; Huang, Ying-Yuan; Chen, Yongsheng

doi:10.1007/s11051-011-0548-z

Cited by 68 publications

(65 citation statements)

References 54 publications

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“…Others have seen similar trends with respect to the effects of IS and NOM on the stability of ENMs (Li et al, 2011b;Saleh et al, 2008). Li et al (2011a) showed that the aggregation rate for CeO 2 was greater at higher KCl and CaCl 2 concentrations, which is similar to the trend we observed in this study for GONP and Ca 2 + suspensions.…”

Section: Graphene Oxide Stabilitysupporting

confidence: 90%

Stability and Transport of Graphene Oxide Nanoparticles in Groundwater and Surface Water

Lanphere

Rogers

Luth

et al. 2014

Environmental Engineering Science

131

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The effects of groundwater and surface water constituents (i.e., natural organic matter [NOM] and the presence of a complex assortment of ions) on graphene oxide nanoparticles (GONPs) were investigated to provide additional insight into the factors contributing to fate and the mechanisms involved in their transport in soil, groundwater, and surface water environments. The stability and transport of GONPs was investigated using dynamic light scattering, electrokinetic characterization, and packed bed column experiments. Stability results showed that the hydrodynamic diameter of the GONPs at a similar ionic strength (2.1 -1.1 mM) was 10 times greater in groundwater environments compared with surface water and NaCl and MgCl 2 suspensions. Transport results confirmed that in groundwater, GONPs are less stable and are more likely to be removed during transport in porous media. In surface water and MgCl 2 and NaCl suspensions, the relative recovery was 94% -3% indicating that GONPs will be very mobile in surface waters. Additional experiments were carried out in monovalent (KCl) and divalent (CaCl 2 ) salts across an environmentally relevant concentration range (0.1-10 mg/L) of NOM using Suwannee River humic acid. Overall, the transport and stability of GONPs was increased in the presence of NOM. This study confirms that planar ''carbonaceous-oxide'' materials follow traditional theory for stability and transport, both due to their response to ionic strength, valence, and NOM presence and is the first to look at GONP transport across a wide range of representative conditions found in surface and groundwater environments.

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Section: Graphene Oxide Stabilitysupporting

confidence: 90%

Stability and Transport of Graphene Oxide Nanoparticles in Groundwater and Surface Water

Lanphere

Rogers

Luth

et al. 2014

Environmental Engineering Science

131

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“…The nanoparticle concentration used for kinetics studies should be low enough; so that sizes change with time can be discerned to follow either a hyperbolic or parabolic trend before particles become large enough to precipitate during DLS monitoring. Hyperbolic aggregation corresponds to a DLA regime and parabolic aggregation indicates RLA behavior [23,24]. The nanofluid concentration used in this part of study was 1.2×10 -3 vol%; this is close to detection limit of the DLS instrument, but was necessary to provide aggregation slow enough such that DLA and RLA could be distinguished without precipitation.…”

Section: Nanofluid Preparationmentioning

confidence: 98%

“…The concentrations of NaCl necessary for RLA or DLA were determined based upon aggregation kinetics, similar to other studies [23,24], where aggregation rates were determined by monitoring particle size changes with time. Using DLS, aggregation rates were recorded with time.…”

Section: Nanofluid Preparationmentioning

confidence: 99%

“…Aggregation rates were monitored in a 4.5 mL methacrylate cuvette for 2 mL of solution under unstirred conditions at 25 o C. In order to capture early stage aggregation, size was obtained with short measurement accumulation times of 15 to 20 seconds. The aggregation regime transforms from RLA to DLA when aggregation rates show no further increase with increasing NaCl concentration [23,24,63]. Trial and error was used to determine the necessary NaCl concentration for DLA and RLA behaviors, and aggregation rates were monitored for coagulant dose between 90 -1000 mM of NaCl.…”

Section: Aggregation Kinetic Studiesmentioning

confidence: 99%

“…RLA transforms into DLA at the critical NaCl concentration. The size growths with increasing NaCl concentration were recorded with time, the growth curve for DLA is hyperbolic trend and RLA is parabolic trend [23,24].…”

Section: Aggregation Kinetic Studiesmentioning

confidence: 99%

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Characterizations of Nanofluid Heat Transfer Enhancements

Johnson¹

2013

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Nanoparticle morphology is thought to be an important factor influencing heat and mass transfer rates in liquid systems. How nanoparticles mechanistically increase heat and mass transfer rates is not well understood. Both dispersed nanoparticles and aggregated nanoparticles are thought to play important roles. Dispersed nanoparticles and associated nanoparticle Brownian movements are purported to cause the enhancements by mixing mechanisms whereas aggregated nanoparticles are purported to cause enhancements by forming highly conductive paths. In this study, morphologies of nanoparticle were quantified in laboratory studies and related to laboratory measured heat and mass transfer rates. No mass transfer enhancements were found in the presence of nanoparticles. Thermal conductivity could be predicted with effective medium theory when aggregated nanoparticle aspect ratio was considered. Nanoparticle morphology is thought to be an important factor influencing heat and mass transfer rates in liquid systems. How nanoparticles mechanistically increase heat and mass transfer rates is not well understood. Both dispersed nanoparticles and aggregated nanoparticles are thought to play important roles. Dispersed nanoparticles and associated nanoparticle Brownian movements are purported to cause the enhancements by mixing mechanisms whereas aggregated nanoparticles are purported to cause enhancements by forming highly conductive paths. In this study, morphologies of nanoparticle were quantified in laboratory studies and related to laboratory measured heat and mass transfer rates.Grant research objectives were to answer fundamental questions related to mechanisms of nanofluid heat transfer enhancer enhancements. Activities in part (1) were designed to answer the question of: Are enhancements related to Brownian nanoparticle motion? Activities in part (2) were conducted to answer the question of: Are enhancements related to the extent of particle aggregation and morphology of aggregated particles, and if so, can the extent of particle aggregation and associated heat transfer enhancements be characterized using fractal dimensions of aggregated nanoparticles? Study parts (1) and (2) comprise the majority of the research effort to satisfy objectives associated with rational for funding support. Additional activities in the final year of the grant were completed once these major research objectives had been met. In study part (3), the morphology characterization techniques developed to study heat transfer mechanisms ...

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Aggregation Kinetics and Fractal Dimensions of Nanomaterials in Environmental Systems

Saleh¹,

Afrooz²,

Aich³

et al. 2016

Engineered Nanoparticles and the Environment: Biophysicochemical Processes and Toxicity

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Aggregation kinetics of CeO2 nanoparticles in KCl and CaCl2 solutions: measurements and modeling

Cited by 68 publications

References 54 publications

Stability and Transport of Graphene Oxide Nanoparticles in Groundwater and Surface Water

Stability and Transport of Graphene Oxide Nanoparticles in Groundwater and Surface Water

Characterizations of Nanofluid Heat Transfer Enhancements

Aggregation Kinetics and Fractal Dimensions of Nanomaterials in Environmental Systems

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