Electrical Properties of Colloidal Particles (OpenStax Chemistry 2e)
Dispersed colloidal particles are often electrically charged. A colloidal particle of iron(III) hydroxide, for example, does not contain enough hydroxide ions to compensate exactly for the positive charges on the iron(III) ions. Thus, each individual colloidal particle bears a positive charge, and the colloidal dispersion consists of charged colloidal particles and some free hydroxide ions, which keep the dispersion electrically neutral. Most metal hydroxide colloids have positive charges, whereas most metals and metal sulfides form negatively charged dispersions. All colloidal particles in any one system have charges of the same sign. This helps keep them dispersed because particles containing like charges repel each other.
The charged nature of some colloidal particles may be exploited to remove them from a variety of mixtures. For example, the particles comprising smoke are often colloidally dispersed and electrically charged. Frederick Cottrell, an American chemist, developed a process to remove these particles. The charged particles are attracted to highly charged electrodes, where they are neutralized and deposited as dust (Figure 1). This is one of the important methods used to clean up the smoke from a variety of industrial processes. The process is also important in the recovery of valuable products from the smoke and flue dust of smelters, furnaces, and kilns. There are also similar electrostatic air filters designed for home use to improve indoor air quality.
Flowers, P., Theopold, K., Langley, R., & Robinson, W. R. (2019, February 14). Chemistry 2e. Houston, Texas: OpenStax. Access for free at: https://openstax.org/books/chemistry-2e
Date Published: January 20, 2014 Publisher: Public Library of Science Author(s): Wei Zhang, Song Chen, Na Li, Jia zheng Zhang, Wei Chen, James P. Brody. http://doi.org/10.1371/journal.pone.0085173 Abstract: Optical microscopy and multi-particle tracking are used to investigate the cross-correlated diffusion of quasi two-dimensional colloidal particles near an oil-water interface. The behaviors of the correlated diffusion along … Continue reading
Research Article: Asymmetrical Polyhedral Configuration of Giant Vesicles Induced by Orderly Array of Encapsulated Colloidal Particles
Date Published: January 11, 2016 Publisher: Public Library of Science Author(s): Yuno Natsume, Taro Toyota, Hélder A. Santos. http://doi.org/10.1371/journal.pone.0146683 Abstract: Giant vesicles (GVs) encapsulating colloidal particles by a specific volume fraction show a characteristic configuration under a hypertonic condition. Several flat faces were formed in GV membrane with orderly array of inner particles. GV shape … Continue reading
Research Article: Scattering of Light by Colloidal Aluminosilicate Particles Produces the Unusual Sky-Blue Color of Río Celeste (Tenorio Volcano Complex, Costa Rica)
Date Published: September 18, 2013 Publisher: Public Library of Science Author(s): Erick Castellón, María Martínez, Sergio Madrigal-Carballo, María Laura Arias, William E. Vargas, Max Chavarría, Christof Markus Aegerter. http://doi.org/10.1371/journal.pone.0075165 Abstract: Río Celeste (Sky-Blue River) in Tenorio National Park (Costa Rica), a river that derives from the confluence and mixing of two colorless streams—Río Buenavista (Buenavista … Continue reading
Date Published: July 15, 2008 Publisher: Public Library of Science Author(s): Karen Otto Abstract: The development of a short-time scale colloidal system introduces flow cytometry as a tool to investigate both physicochemical and molecular aspects of bacterial adhesion to solid surfaces. Partial Text: Bacteria are small unicellular organisms who could well enjoy a bohemian life—moving … Continue reading