Aggregation behavior of TiO2 nanoparticles in municipal effluent: Influence of ionic strengthen and organic compounds. (15th October 2017)

• Record Type: Journal Article
• Authors: Ren, Meijie; Horn, Harald; Frimmel, Fritz H.
• Is Part Of: Water research. Volume 123(2017)
• Page Start: 678
• Page End: 686
• Publication Date: 2017-10-15
• Subjects: TiO2 nanoparticles -- Aggregation -- DOM -- Electrolytes -- Municipal effluent; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2017.07.021
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: The influence of ionic strengthen and dissolved organic matter (DOM) on the aggregation of TiO2 nanoparticles (NPs) in municipal effluent was investigated. The results demonstrated that DOM promoted the mobility of NPs in aquatic system by synergism between static repulsion and steric effect, while electrolytes were opposite by charge-neutralization. The physical-chemical characteristics of DOM played the major role on the mobility of NPs. Bovine serum albumin (BSA) showed the strongest enhancement on the mobility of TiO2 NPs. High adsorption of BSA introduced vast negative charges on the TiO2 NPs' surface, leading to static repulsion and neutralizing positive charges of electrolytes in surrounding as well. By contrast, another protein α-amylase retarded the aggregation rate of TiO2 NPs through steric repulsion of the long-chain construction. Humic substances (Fulvic acid and alginate) also reflected the combination of static repulsion and steric effect. However, in the high electrolytes concentration (especially Ca 2+ ), the long-chain aliphatic compounds were prone to form calcium bridge which increased the hydrodynamic diameter of TiO2 aggregates consequently. Sodium dodecylbenzene sulfonate (SDBS) showed low adsorption capacity, while the unabsorbed SDBS retarded the aggregates caused by the changes of pH and electrolytes. These data indicated that decreasing of DOC concentration in aqueous system was important to reduce the mobility and potential risk of NPs in aqueous system. Graphical abstract: Image Highlights: Stabilization effect on TiO2 was synergistic by static and steric repulsion. The characteristics of DOM played a major role on the mobility of NPs. NPs were liable to precipitate in the region with high hardness water quality. Decreasing of DOC concentration decreased the mobility of NPs in aqueous system.