This study examines the dyeing efficacy of treated cotton and polyester textiles utilising carboxymethyl cellulose (CMC)
derived from agricultural by-products, specifically peanut shells and rice straw, as sustainable textile modifiers. The textiles
were coloured using three natural dyes—peanut red skin, red onion peel, and henna extracts—under regulated acidic condi
tions (pH 5, 60 °C), both with and without citric acid as a crosslinking agent. The impact of dyeing duration (15–60 min),
CMC source, fabric type, dye type, and the presence of a crosslinker on colour strength (K/S) was methodically assessed.
The findings indicated a gradual increase in K/S values with extended dyeing time, with maximum colour strength at 60
minutes for all methods. Fabrics treated with CMC derived from rice straw consistently showed superior K/S values com
pared to those treated with CMC from peanut shells, due to greater availability of functional groups and stronger dye-fibre
interactions. Dyed textiles lacking a citric acid crosslinker exhibited higher colour strength relative to their crosslinked
counterparts, attributed to increased fibre swelling and enhanced accessibility of active binding sites for natural dyes. Among
the examined colours, peanut red skin extract exhibited the greatest colouring efficacy. The results underscore the viability
of waste-derived CMC as a sustainable textile treatment and verify that optimised non-crosslinked systems can achieve
enhanced colour depth with natural dyes, thereby endorsing eco-friendly dyeing procedures.