Cadmium Sulfide - Reactions

Reactions

Cadmium sulfide is soluble in (actually degraded by) acids, and this conversion has been investigated as a method of extracting the pigment from waste polymers e.g. HDPE pipes:

CdS + 2 HCl → CdCl2 + H2S

When sulfide solutions containing dispersed CdS particles are irradiated with light hydrogen gas is generated:

H2S → H2 + S ΔHf = +9.4 kcal/mol

The proposed mechanism involves the electron/hole pairs created when incident light is absorbed by the cadmium sulfide followed by these reacting with water and sulfide:

Production of an electron hole pair
CdS + → e− + hole+
Reaction of electron
2e− + 2H2O → H2 + 2OH−
Reaction of hole
2hole+ + S2− → S

Read more about this topic:  Cadmium Sulfide

Famous quotes containing the word reactions:

    In this Journal, my pen is a delicate needle point, tracing out a graph of temperament so as to show its daily fluctuations: grave and gay, up and down, lamentation and revelry, self-love and self-disgust. You get here all my thoughts and opinions, always irresponsible and often contradictory or mutually exclusive, all my moods and vapours, all the varying reactions to environment of this jelly which is I.
    W.N.P. Barbellion (1889–1919)

    Separation anxiety is normal part of development, but individual reactions are partly explained by experience, that is, by how frequently children have been left in the care of others.... A mother who is never apart from her young child may be saying to him or her subliminally: “You are only safe when I’m with you.”
    Cathy Rindner Tempelsman (20th century)

    We have all had the experience of finding that our reactions and perhaps even our deeds have denied beliefs we thought were ours.
    James Baldwin (1924–1987)