Discoloration of textile dyes by peroxidases from melon, chayote, lemon and orange peels

Abstract

Traditional textile finishing industry consumes about 100 liters of water to process about 1 Kg of textile materials, it has been estimated that about 10% of the dye used in the process does not bind to the fibers. This wastewater creates environmental problems due to the generation of hazardous degradation products from dyes. In wastewater treatment plants dyes remain unchanged and are discharged to rivers. Additionally there are some advanced treatment systems to discolored the textile dye but they are expensive. The aim of this study was to test different materials: a) lemon peel, b) melon peel, c) orange peel and d) chayote peel, to discolor solutions of three textile dyes: i) indigo carmine, ii) direct brown 2 and iii) direct black 22. The different peels were blended with water, centrifuged and filtered with paper to get the extract; then the enzymatic extract was incubate with the dye solution at room temperature and with magnetic stirrer during 24 hours Periodically it was taken samples and analyzed with the UV-Vis spectrophotometer, and it was calculated the % of discoloration by measuring the absorbance changes. Lemon, orange and chayote peels discolored both the indigo carmine and the direct brown 2 solution in different percentage; melon peel only discolored the indigo, whereas direct black 2 did not have an important discoloration with any of the biological materials. Indigo was discolored easily than others dyes, because it redox potential is the lowest of the three dyes. For indigo, discoloration reached 19% using melon shell, 56% using chayote shell, 50% using lemon and 21% using orange peel, in 24 hours. Results are very interesting because we have demonstrated that cheap material like vegetable peels can be used to treat some textile dye solutions efficiently.