The utilisation of wool as a catalyst and as a support for catalysts

Textiles are an emerging class of support material for catalysts, and are available in many different structures at a modest cost from a well-established industry. This review discusses 87 studies of wool and reconstituted wool as catalysts, and supports for catalysts, along with informative complementary studies. The catalytic properties of wool itself were investigated in two studies, and it was shown to be an effective solid sulphonic acid catalyst. A wide variety of catalysts have been applied to wool, i.e. metal complexes, metal oxides, metallic particles, enzymes, microbes and small organic molecules. Wool supported catalysts generally showed good activity, specificity, durability, and re-usability and this is attributable to the amino acid composition of wool enabling a wide range of protocols for attaching catalysts. Reconstituted wool is an effective support for enzyme, metal oxide and organic photoactive catalysts and its low toxicity towards cells makes it a promising support for phototherapy catalysts. This review has shown the wide breadth of research that has been undertaken on wool catalysts and wool-supported catalysts and many interesting developments will be made in the future. For instance, hair and feathers have been used as templates for preparing highly structured materials that may prove effective as catalysts, and wool warrants investigation in this area. Other areas of particular interest for the future are wool sulphonic acid catalysts, and supporting organic molecules onto wool to prepare synthetic enzymes.