Bleaching plant foliage

Page last updated: Friday, 9 December 2016 - 1:58pm

Please note: This content may be out of date and is currently under review.

Post-bleach treatments

Destruction of residual chlorine

The human nose can detect chlorine concentrations of as low as 0.03 parts per million (ppm). Residual chlorine can easily be destroyed by rinsing the foliage in a dilute solution of thiourea or sulfur dioxide (as metabisulphite or hydrosulphite). Sulphur dioxide can also conveniently be applied as a gas.

Strengthening bleached foliage

If allowed to dry, the cellulose plant skeleton that is left after bleaching will become very brittle. Water has a plasticising effect, so a humectant is usually added in the final stages to attract water. Calcium chloride attracts water well, sodium chloride slightly less so. Glycerine has also been used.

Caution: Glycerine and bleach will explode on contact.

Starch or water-soluble plastic adhesives, such as polyvinyl alcohol, may also be suitable.