The recent advances in nanotechnology and the corresponding increase in the use of nanomaterials in products in every sector of society have resulted in uncertainties regarding environmental impacts. The objectives of this review are to introduce the key aspects pertaining to nanomaterials in the environment and to discuss what is known concerning their fate, behavior, disposition, and toxicity, with a particular focus on those that make up manufactured nanomaterials. This review critiques existing nanomaterial research in freshwater, marine, and soil environments. It illustrates the paucity of existing research and demonstrates the need for additional research. Environmental scientists are encouraged to base this research on existing studies on colloidal behavior and toxicology. The need for standard reference and testing materials as well as methodology for suspension preparation and testing is also discussed.

Nanomaterials in the environment: Behavior, fate, bioavailability, and effects

Engineered nanomaterials (ENM) are already used in many products and consequently released into environmental compartments. In this study, we calculated predicted environmental concentrations (PEC) based on a probabilistic material flow analysis from a life-cycle perspective of ENM-containing products. We modeled nano-TiO2, nano-ZnO, nano-Ag, carbon nanotubes (CNT), and fullerenes for the U.S., Europe and Switzerland. The environmental concentrations were calculated as probabilistic density functions and were compared to data from ecotoxicological studies. The simulated modes (most frequent values) range from 0.003 ng L−1 (fullerenes) to 21 ng L−1 (nano-TiO2) for surface waters and from 4 ng L−1 (fullerenes) to 4 μg L−1 (nano-TiO2) for sewage treatment effluents. For Europe and the U.S., the annual increase of ENMs on sludge-treated soil ranges from 1 ng kg−1 for fullerenes to 89 μg kg−1 for nano-TiO2. The results of this study indicate that risks to aquatic organisms may currently emanate from nano-Ag, n...

Modeled Environmental Concentrations of Engineered Nanomaterials (TiO2, ZnO, Ag, CNT, Fullerenes) for Different Regions

Antimicrobial nanomaterials for water disinfection and microbial control: Potential applications and implications

Occurrence, behavior and effects of nanoparticles in the environment.

Membranes have an increasingly important role in alleviating water scarcity and the pollution of aquatic environments. Promising molecular-level design approaches are reviewed for membrane materials, focusing on how these materials address the urgent requirements of water treatment applications.

Materials for next-generation desalination and water purification membranes

This study investigates the aqueous stability of multi-walled carbon nanotubes (MWNTs) in the presence of natural organic matter (NOM). MWNTs were readily dispersed as an aqueous suspension in both model NOM (Suwannee River NOM (SR-NOM)) solutions and natural surface water (actual Suwannee River water with unaltered NOM background), which remained stable for over 1 month. Microscopic analyses suggested that the suspension consisted primarily of individually dispersed MWNTs. Concentrations of MWNTs suspended in the aqueous phase, quantified using thermal optical transmittance analysis (TOT), ranged from 0.6 to 6.9 mg/L as initial concentrations of MWNT and SR-NOM were varied from 50 to 500 mg/L and 10 to 100 mg/L, respectively. Suwannee River water showed a similar MWNT stabilizing capacity as compared to the model SR-NOM solutions. For the same initial MWNT concentrations, the concentrations of suspended MWNT in SR-NOM solutions and Suwannee River water were considerably higher than that in a solution of ...

Natural organic matter stabilizes carbon nanotubes in the aqueous phase

The effect of natural organic matter (NOM) characteristics and water quality parameters on NOM adsorption to multiwalled carbon nanotubes (MWNT) was investigated. Isotherm experiment results were fitted well with a modified Freundlich isotherm model that took into account the heterogeneous nature of NOM. The preferential adsorption of the higher molecular weight fraction of NOM was observed by size exclusion chromatographic analysis. Experiments performed with various NOM samples suggested that the degree of NOM adsorption varied greatly depending on the type of NOM and was proportional to the aromatic carbon content of NOM. The NOM adsorption to MWNT was also dependent on water quality parameters: adsorption increased as pH decreased and ionic strength increased. As a result of NOM adsorption to MWNT, a fraction of MWNT formed a stable suspension in water and the concentration of MWNT suspension depended on the amount of NOM adsorbed per unit mass of MWNT. The amount of MWNT suspended in water was also affected by ionic strength and pH. The findings in this study suggested that the fate and transport of MWNT in natural systems would be largely influenced by NOM characteristics and water quality parameters.

Hoon Hyung

Papers

Natural organic matter stabilizes carbon nanotubes in the aqueous phase

Natural Organic Matter (NOM) Adsorption to Multi-Walled Carbon Nanotubes: Effect of NOM Characteristics and Water Quality Parameters

A mechanistic study on boron rejection by sea water reverse osmosis membranes

Dispersion of C60 in natural water and removal by conventional drinking water treatment processes.

Modeling boron rejection in pilot- and full-scale reverse osmosis desalination processes