Figures index

From

Redox Reactions in Sodium Alginate Beads

Matthias Ducci

World Journal of Chemical Education. 2019, 7(2), 40-44 doi:10.12691/wjce-7-2-2
  • Figure 1. Molecular formulas of β-D-mannuronate (left) and α-L-guluronate (right)
  • Figure 2. Model of the gelation process (the zigzag lines symbolise the polyguluronate sequences and the green dots indicate the calcium ions; modified according to [1])
  • Figure 3. Alginate beads have a shell consisting of calcium alginate sparingly soluble in water (Photograph: Ducci)
  • Figure 4. Alginate balls with enclosed universal indicator in acidic, neutral and alkaline solutions (from left to right) (Photograph: Ducci)
  • Figure 5. The fluorescent dye pyranine
  • Figure 6. Alginate beads containing the fluorescent dye pyranine when irradiated by a UV lamp (above, λ = 365 nm). Below: The same alginate beads exposed to UV light following treatment in a strongly acidic solution. (Photographs: Ducci, [5])
  • Figure 7. Alginate beads loaded with starch, sodium nitrate and potassium iodide in hydrochloric acid (from left to right: some few seconds after covering with diluted hydrochloric acid; after about 30 s; after about 2 min). When the photographs were taken, the glass vessel was standing on a light panel. (Photographs: Ducci)
  • Figure 8. Iodine-starch complex alginate beads in alkaline sodium thiosulfate solution (left: about 2 min following the addition of the beads to the solution; right: after about 7 min). (Photographs: Ducci)
  • Figure 9. Alginate beads with enclosed sodium permanganate in neutral, alkaline and acidic sodium sulphite solutions (from left to right; the photographs were taken about 2 min after covering) (Photographs: Ducci)
  • Figure 10. Alginate beads loaded with starch as well as iodide and iodate ions in strongly diluted sulphuric acid solution (left: some few seconds after immersion; right: after 2 to 3 min) (Photographs: Ducci)