Properties of Commercial Nanoparticles that Affect Their Removal During Water Treatment

Westerhoff, Paul; Zhang, Yang; Crittenden, John C.; Chen, Yongsheng

doi:10.1002/9780470396612.ch4

Cited by 10 publications

(7 citation statements)

References 63 publications

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“…As an example, the efficiency of the treatment plants for removing the ENMs could either be low or high. Preliminary findings of Westerhoff and others 36 indicated low to high WWTP removal efficiencies of different ENM types from the wastewater. For instance, the nTiO 2 removal efficiencies values were reported as 90% whereas for nZnO and nFe 2 O 3 ENMs – also used in cosmetics –were 5% and 30%, respectively.…”

Section: Resultsmentioning

confidence: 91%

“…The nAg removal efficiency used were based on the reported values for silver in WWTP by Shafer et al, 37 ranging from 94% to 99%, and Daxbeck et al, 38 of 85% for the minimum, probable, and maximum scenarios, respectively. Generally, in developing countries, most WWTPs are characterized by low operational efficiencies, therefore, the values reported for nTiO 2 36 were regarded as ‘high’ (since >80%) in this study. This is because the values were derived based on experimental plant set-up in the developed countries.…”

Section: Resultsmentioning

confidence: 99%

“…However, with no published data for WWTP for the JHB City, then, the high removal efficiency values in our study were assumed to be 20%-30% lower than those reported in the literature. [36][37][38] On the other hand, discussions with experts knowledgeable in the operations of many WWTPs in the JHB City suggested the overall removal efficiency could in practice be as low as 45% (personal communication). These values were used to develop a case of potential environmental impact when the ENM removal efficiency of the treatment plant was very low.…”

Section: Pec Estimationsmentioning

confidence: 99%

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Simulated environmental risk estimation of engineered nanomaterials: A case of cosmetics in Johannesburg City

Musee

2010

Hum Exp Toxicol

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This paper attempts to quantify the potential risks posed by engineered nanomaterials (ENMs) to the aquatic and terrestrial ecosystems from cosmetic-based nanoproducts. The predicted environmental concentrations (PEC) were modelled for the silver (nAg) and titanium dioxide (nTiO2) nanoparticles embedded in cosmetic nanoproducts. The Johannesburg Metropolitan City (JHB City), in South Africa, was used as the reference study area. A mathematical model was applied to compute the quantities of ENMs flows from the cosmetic nanoproducts into the JHB City aquatic and terrestrial ecosystems. The risk quotient (RQ) of the nanoscale materials were evaluated as a ratio of PEC to the predicted no effect concentrations (PNEC). RQ values showed wide variance due to factors like; the quantities of ENMs, the fate and pathways of ENMs in the aquatic and terrestrial ecosystems, efficiency of the wastewater treatment plants (WWTP) as well as the economic and demographic data for South Africa and Switzerland. For the aquatic environment, the PEC values of nAg ranged from 2.80 × 10−3 to 6.19 × 10−1 μg L−1 whereas for nTiO2 the values ranged from 2.7 0 × 10−3 to 2.70 × 10−1 μg L−1 under the realistic dilution factor of 1 with the WWTP functioning at high removal efficiency regime. The RQ values in the aquatic ecosystems were mostly >1, indicating the potential risk of both nAg and nTiO2 but <<<1 in the terrestrial ecosystems. Our results provide the first quantification of ENMs potential risk into the environment Johannesburg City in a developing country’s natural and technical settings.

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Section: Resultsmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Section: Pec Estimationsmentioning

confidence: 99%

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Simulated environmental risk estimation of engineered nanomaterials: A case of cosmetics in Johannesburg City

Musee

2010

Hum Exp Toxicol

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“…Yet considering their potential importance, potable water treatment unit processes (specifically coagulation) as related to ENP removal have, to date, received only scant attention. Westerhoff et al (16) examined the relationship between ENP characteristics and behavior in aquatic systems, suggesting aggregation potential was determined by surface charge and potential for ligand complexation (16). Zhang et al (17) reported that coagulation removal efficiencies of select metal oxide nanoparticles ranged between 20% and 60% and Holbrook et al (18) confirmed that MWCNTs could be removed from the aqueous phase via coagulation using either ferric chloride or aluminum sulfate (alum).…”

Section: Introductionmentioning

confidence: 99%

Impact of Source Water Quality on Multiwall Carbon Nanotube Coagulation

Holbrook

Kline

Filliben

2010

Environ. Sci. Technol.

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Potable water treatment facilities may become an important barrier in limiting human exposure to engineered nanoparticles (ENPs) as ENPs begin to contaminate natural aquatic systems. Coagulation of ENPs will likely be a major process that controls the ENP fate and the subsequent removal in the aqueous phase. The influence that source water quality has on ENP coagulation is still relatively unknown. The current study uses a 2(3) x 2(4-1) fractional factorial design to identify seven key surface water constituents that affect multiwall carbon nanotube (MWCNT) coagulation. These seven factors include: influent concentrations of kaolin, organic matter (OM), alginate, and MWCNTs; type and dosage of coagulant; and method of MWCNT stabilization. MWCNT removal was most affected by coagulant type and dosage, with alum outperforming ferric chloride at circumneutral pH. None of the other factors were universally significant but instead depended on coagulant type, dose, and method of stabilization. In all cases where factors were found to have a significant impact on MWCNT removal, however, the relationship was consistent: higher influent concentrations of kaolin and alginate improved MWCNT removal while higher influent concentrations of OM hindered MWCNT coagulation. Once MWCNTs are released into the natural environment, their coagulation behavior will be determined by the type and quantity of pollutants (i.e., factors) present in the aquatic environment and are governed by the same mechanisms that influence the colloidal stability of "natural" nanoparticles.

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“…Nevertheless, a significant amount of ENM in wastewater will reach the wastewater sludge through the aggregation and settling mechanisms. Westerhoff et al (2008a) reported the aggregation of TiO 2 and CdSe quantum dots by coagulation using alum.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Sources, Distribution, Environmental Fate, and Ecological Effects of Nanomaterials in Wastewater Streams

Kunhikrishnan

Shon

Bolan

et al. 2014

Critical Reviews in Environmental Science and Technology

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Engineered nanomaterials (ENM) are manufactured, as opposed to being an incidental by-product of combustion or a natural process, and they often have unique or novel properties that emerge from their small size. These materials are being used in an expanding array of consumer products and, like all technological developments, have both benefits and risks. As the use of ENM in consumer products becomes more common, the amount of these nanomaterials entering wastewater stream increases. Estimates of nanomaterials production are in the range of 500 and 50,000 tons per year for silver and titanium dioxide (TiO 2 ) alone, respectively. Nanomaterials enter the wastewater stream during the production, usage, and disposal of nanomaterial-containing products. The predicted values of nanomaterials range from 0.003 (fullerenes) to 21 ng L −1 (nano-TiO 2 ) for surface waters, and from 4 ng L −1 (fullerenes) to 4 g L −1 (nano-TiO 2 ) for sewage treatment effluents. Therefore, investigating the fate of nanomaterials in wastewater streams is critical for risk assessment and pollution control. This review aims to firstly, identify the sources of nanomaterials reaching wastewater streams, then determine their occurrence and distribution, and finally discuss their fate in relation to human and ecological health, and environmental impact.

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Properties of Commercial Nanoparticles that Affect Their Removal During Water Treatment

Cited by 10 publications

References 63 publications

Simulated environmental risk estimation of engineered nanomaterials: A case of cosmetics in Johannesburg City

Simulated environmental risk estimation of engineered nanomaterials: A case of cosmetics in Johannesburg City

Impact of Source Water Quality on Multiwall Carbon Nanotube Coagulation

Sources, Distribution, Environmental Fate, and Ecological Effects of Nanomaterials in Wastewater Streams

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