A review of non-DLVO interactions in environmental colloidal systems

Grasso, Domenico; Subramaniam, Kavitha; Butkus, Michael A.; Strevett, Keith A.; Bergendahl, John

doi:10.1023/a:1015146710500

Cited by 396 publications

(312 citation statements)

References 101 publications

Supporting

Mentioning

307

Contrasting

Unclassified

Order By: Relevance

“…The CCC of nano-CuO was ∼40 mM NaCl at pH 7 in the absence of NOM (SI Figure S8). CCC increased to ∼75 mM in the presence of 0.25 mg/L SRN but could not be determined in the presence of EPS due to steric stabilization (which typically does not follow the classical DLVO theory 26 ). Similarly, nano-CuO was relatively stable up to 10 mM at pH 11 in the absence of NOM.…”

Section: ■ Experimental Sectionmentioning

confidence: 93%

Influence of Extracellular Polymeric Substances on the Long-Term Fate, Dissolution, and Speciation of Copper-Based Nanoparticles

Adeleye

Conway

Pérez

et al. 2014

Environ. Sci. Technol.

216

217

View full text Add to dashboard Cite

ABSTRACT:The influence of phytoplankton-derived soluble extracellular polymeric substances (EPS), pH, and ionic strength (IS) on the dissolution, speciation, and stability of nano-CuO, nano-Cu, and Kocide (a micron sized Cu(OH) 2 -based fungicide) was investigated over 90 days. EPS improved the stability of commercial copper-based nanoparticles (CBNPs) in most conditions, in addition to influencing their dissolution. The dissolution rate was pH 4 ≫ pH 7 > pH 11. The presence of EPS correlated with higher dissolved Cu at pH 7 and 11, and lower dissolved Cu at pH 4. More dissolution was observed at higher IS (NaCl) due to complexation with Cl − . Dissolution of nano-CuO at pH 7 increased from 0.93% after 90 days (without EPS) to 2.01% (with 5 mg-C EPS/L) at 10 mM IS. Nano-CuO dissolved even more (2.42%) when IS was increased to 100 mM NaCl (with EPS). The ratio of freeCu 2+ /total dissolved Cu decreased in the presence of EPS, or as pH and/or IS increased. On a Cu mass basis, Kocide had the highest dissolved and suspended Cu at pH 7. However, dissolution of nano-Cu resulted in a higher fraction of free Cu 2+ , which may make nano-Cu more toxic to pelagic organisms. ■ INTRODUCTIONGlobal production of copper-based nanoparticles (CBNPs) was estimated at ∼200 t/yr in 2010, and is increasing. 1 CBNPs have found use in cosmetics, pigments, paints and coatings, electronics, and pesticides. 2−4 These applications may lead to direct exposure of CBNPs to the environment due to normal use, product wear-and-tear, and/or end-of-life disposal. 1 Toxicity of CBNPs and composites to organisms has been demonstrated. 2,5−8 It is therefore important to understand the long-term fate and transformations of these materials in aquatic systems in order to predict exposure to at-risk organisms.Stability and dissolution of engineered nanoparticles (ENPs) depend on ionic strength (IS), pH, and natural organic material (NOM). 9−12 Rapid aggregation of nano-Cu was reported in freshwater by Griffitt et al. 5 The authors also found that less than 0.1% of the nano-Cu dissolved in 48 h in the freshwater media used (pH 8.2). 98% dissolution of nano-Cu was however reported at pH 6 in "uterine-fluid" after a week, 13 demonstrating the importance of pH and media composition on CBNPs' dissolution. Mudunkotuwa and co-workers 14 reported increased dissolution of aged and new CBNPs in the presence of organic acids. Similarly, Worthington et al. 15 showed that the chitosan improved stability and dissolution of nano-Cu. To our knowledge, no studies have previously investigated the effects of naturally occurring NOM such as extracellular polymeric substances (EPS) on the stability and dissolution of CBNPs. EPS are synthesized by microorganisms, which are abundant in natural aquatic systems. EPS are mainly composed of polysaccharides, proteins, nucleic acids, and other polymers; and their composition may vary spatially and temporally even within the same species. 16 EPS may interact with ENPs, thus affecting their fate and transformation. 17 Additional...

show abstract

Section: ■ Experimental Sectionmentioning

confidence: 93%

Influence of Extracellular Polymeric Substances on the Long-Term Fate, Dissolution, and Speciation of Copper-Based Nanoparticles

Adeleye

Conway

Pérez

et al. 2014

Environ. Sci. Technol.

216

217

View full text Add to dashboard Cite

show abstract

“…The major issues with classical DLVO theory for predicting the stability of nanoparticles are as follows [48]: (1) DLVO only describes the short range interaction within 0.1-10 nm due to the exponential decay of the forces with distance [164,165]. Distances out of this scope will probably result in disagreement due to hydration forces [166]; (2) multivalent electrolytes with high concentration may result in the failure of DLVO.…”

Section: Dlvomentioning

confidence: 99%

“…However, it should be noted that an accurate determination of each force is generally impossible. A case in point is the origin of hydrophobic and hydrophilic interactions, which is still not completely understood [165].…”

Section: Extended Dlvo (X-dlvo)mentioning

confidence: 99%

Heteroaggregation of nanoparticles with biocolloids and geocolloids

Wang

Adeleye

Huang

et al. 2015

Advances in Colloid and Interface Science

170

View full text Add to dashboard Cite

The application of nanoparticles has raised concern over the safety of these materials to human health and the ecosystem. After release into an aquatic environment, nanoparticles are likely to experience heteroaggregation with biocolloids, geocolloids, natural organic matter (NOM) and other types of nanoparticles. Heteroaggregation is of vital importance for determining the fate and transport of nanoparticles in aqueous phase and sediments. In this article, we review the typical cases of heteroaggregation between nanoparticles and biocolloids and/or geocolloids, mechanisms, modeling, and important indicators used to determine heteroaggregation in aqueous phase. The major mechanisms of heteroaggregation include electric force, bridging, hydrogen bonding, and chemical bonding. The modeling of heteroaggregation typically considers DLVO, X-DLVO, and fractal dimension. The major indicators for studying heteroaggregation of nanoparticles include surface charge measurements, size measurements, observation of morphology of particles and aggregates, and heteroaggregation rate determination. In the end, we summarize the research challenges and perspective for the heteroaggregation of nanoparticles, such as the determination of α hetero values and heteroaggregation rates; more accurate analytical methods instead of DLS for heteroaggregation measurements; sensitive analytical techniques to measure low concentrations of nanoparticles in heteroaggregation systems; appropriate characterization of NOM at the molecular level to understand the structures and fractionation of NOM; effects of different types, concentrations, and fractions of NOM on the heteroaggregation of nanoparticles; the quantitative adsorption and desorption of NOM onto the surface of nanoparticles and heteroaggregates; and a better understanding of the fundamental mechanisms and modeling of heteroaggregation in natural water which is a complex system containing NOM, nanoparticles, biocolloids and geocolloids.

show abstract

“…Such an observation cannot be simply explained by DLVO theory. Fulvic acids are chemically heterogeneous colloids with potential interactions due to non-DLVO effects (Grasso 2002) such as hydratation effects, hydrogen bonding or non polar interactions. Since the hydrodynamic diameter of FA is around 1-2 nm , the interaction of a FA with a hematite particle (d h =75 nm) corresponded to their adsorption (Sposito 1984;Gu et al 1994), resulting primarily in the modification of the colloidal properties, including the surface potential.…”

Section: Discussionmentioning

confidence: 99%

“…Non DLVO forces such as steric interactions, hydration pressure, hydrogen bonding and hydrophobic effects, although rarely considered in quantitative attempts to model colloidal interactions, are more recently being recognized as important forces contributing to the coagulation of environmental colloids (Grasso 2002). For example, in environmental (aqueous) systems, it is now clear that non DLVO hydration effects are possible due to the reorganization of surface bound water upon approach of the colloidal particles.…”

Section: Non-dlvo Interactionsmentioning

confidence: 99%

Contrasting Roles Of Natural Organic Matter On Colloidal Stabilization And Flocculation In Freshwaters

Reinhardt¹

2004

Flocculation in Natural and Engineered Environmental Systems

View full text Add to dashboard Cite

A review of non-DLVO interactions in environmental colloidal systems

Cited by 396 publications

References 101 publications

Influence of Extracellular Polymeric Substances on the Long-Term Fate, Dissolution, and Speciation of Copper-Based Nanoparticles

Influence of Extracellular Polymeric Substances on the Long-Term Fate, Dissolution, and Speciation of Copper-Based Nanoparticles

Heteroaggregation of nanoparticles with biocolloids and geocolloids

Contrasting Roles Of Natural Organic Matter On Colloidal Stabilization And Flocculation In Freshwaters

Contact Info

Product

Resources

About