Long-term colloidal stability and metal leaching of single wall carbon nanotubes: Effect of temperature and extracellular polymeric substances

Adeleye, Adeyemi S.; Keller, Arturo A.

doi:10.1016/j.watres.2013.11.032

Cited by 101 publications

(73 citation statements)

References 37 publications

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“…Aggregation and sedimentation kinetics were studied using the Zetasizer and time-resolved optical absorbency (Shimadzu 1601 UV−vis spectrophotometer) respectively. 17 Detailed information on aggregation, CCC determination and sedimentation experiments are in the SI.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

“…16 EPS may interact with ENPs, thus affecting their fate and transformation. 17 Additionally, the long-term fate and transformation of CBNPs in aqueous media has not been reported in the literature.Studies commonly investigate the aggregation of ENPs in order to predict their environmental fate. In this study, however, we also investigated the fate of a commercial Cu(OH) 2 -based product, Kocide 3000 (denoted Kocide).…”

mentioning

confidence: 99%

“…A SRN stock solution was prepared as described in Supporting Information (SI). Soluble EPS was extracted from a marine phytoplankton, Isochrysis galbana, as described in a previous study 17 and summarized in the SI.EPS was characterized by measuring carbohydrate and protein concentrations using anthrone method and modified Lowry protein assay, respectively. 19,20 Total organic carbon (TOC) was determined using a Shimadzu 5000A TOC analyzer.…”

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confidence: 99%

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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.

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216

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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...

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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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.

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216

217

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“…In the nanoscale, more atoms are found at the surfaces, which makes the nanoparticles more reactive [1]. One case in point is that nanoparticles can quickly agglomerate into larger particles due to higher surface energy [1,[14][15][16].…”

Section: Nanoparticlesmentioning

confidence: 99%

Heteroaggregation of nanoparticles with biocolloids and geocolloids

Wang

Adeleye

Huang

et al. 2015

Advances in Colloid and Interface Science

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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.

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Colloidal Stability in Water of Modified Carbon Nanotube: Comparison of Different Modification Techniques

Seneewong-Na-Ayutthaya

Pongprayoon

O’Rear

2016

Macro Chemistry & Physics

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The colloidal stability of carbon nanotube (CNT) in water is an important property for several applications. Three different functionalization approaches defined as nondestructive techniques have been carried out to modify the CNT surface and the product CNT compared. First, admicellar polymerization is used to form a water‐soluble polymer on CNT with two different polymers, polyacrylic acid and polyvinyl acetate (PVAc). Second, coatings of soluble biopolymers are applied using dextran and chitosan. Third, mild acid oxidation conditions from the literature are employed with hydrogen peroxide (H2O2) and with potassium permanganate (KMnO4) as oxidizing agents. The colloidal stability of modified CNT is examined by sedimentation and by turbidity measurements along with laser particle size analysis. Thermogravimetric Analysis, energy dispersive X‐ray analysis, scanning electron microscope, and transmission electron microscopy are used to confirm that modification of the CNT is successfully implemented with each technique. Lastly, FT‐Raman is used to assess damage to the CNT structure after modification. A focus of the turbidity measurements is quantitative analysis using numerical integration of variability to evaluate colloidal stability. All modified CNT samples clearly yield improved aqueous dispersions. For each of the three approaches, the better option is KMnO4 for mild acid oxidation, PVAc for admicellar polymerization, and chitosan for biopolymer deposition.

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Long-term colloidal stability and metal leaching of single wall carbon nanotubes: Effect of temperature and extracellular polymeric substances

Cited by 101 publications

References 37 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

Colloidal Stability in Water of Modified Carbon Nanotube: Comparison of Different Modification Techniques

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