Table 2

From: Chemical, ecotoxicological characteristics, environmental fate, and treatment methods applied to cyanide-containing wastewater

Hydrolysis

\(\begin{array}{cc}{{\rm{HCN}}}_{\left({\rm{aq}}\right)}\mathop{\longrightarrow }\limits^{{{\rm{2}}{\rm{H}}}_{{\rm{2}}}{\rm{O}}}{{\rm{HCOO}}}_{\left({\rm{aq}}\right)}^{-}+{{\rm{NH}}}_{{\rm{4}}\left({\rm{aq}}\right)}^{+}\end{array}\)

(6)

Thiocyanate formation

\(\begin{array}{cc}{{\rm{CN}}}_{\left({\rm{aq}}\right)}^{-}+{{\rm{HS}}}_{\left({\rm{aq}}\right)}^{-}\leftrightarrows {{\rm{SCN}}}_{\left({\rm{aq}}\right)}^{-}+{{\rm{H}}}_{\left({\rm{aq}}\right)}^{+}+2{e}^{-}\end{array}\)

(7)

Complexation

\({{\rm{CN}}}_{\left({\rm{aq}}\right)}^{-}\mathop{\to }\limits^{{{\rm{M}}}^{{\rm{X}}+}}{\left[{\rm{M}}{\left({\rm{CN}}\right)}_{{\rm{m}}}\right]}_{\left({\rm{aq}}\right)}^{{\rm{n}}-}\)

Where, M = Cu, Ni, Zn

(8)

\(\begin{array}{cc}{6{\rm{HCN}}}_{({\rm{aq}})}+{{\rm{Fe}}}_{({\rm{aq}})}^{3+}\rightleftarrows {[{{\rm{Fe}}({\rm{CN}})}_{6}]}_{({\rm{aq}})}^{3-}+{6{\rm{H}}}_{({\rm{aq}})}^{+}\end{array}\)

(9)

\({6{\rm{HCN}}}_{({\rm{aq}})}+{{\rm{Fe}}}_{({\rm{aq}})}^{2+}\rightleftarrows {\left[{\rm{Fe}}{\left({\rm{CN}}\right)}_{6}\right]}_{({\rm{aq}})}^{4-}+{6{\rm{H}}}_{\left({\rm{aq}}\right)}^{+}\)

(10)

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