In this article a novel approach for a catalytic advanced oxidation process using H2O2/UV/MnTACN isinvestigated, for the decolouration of Reactive Blue 4 (RB4) containing wastewater at room temperature. The catalyst 1,4,7-trimethyl-1,4,7-triazacyclononane (MnTACN) was not added to the batch reactor where the advanced oxidation process(AOP) was carried out conventionally, but was first applied to the cotton fabric to form a suitable catalyst carrier with a highspecific surface area. With the given experimental parameters (0.777 g/l H2O2; a mercury (Hg) lamp at 500 W; 40 mg/lsolution of Reactive Blue 4; room temperature), complete decolourisation with the MnTACN catalyst was achieved in only20 minutes. When the MnTACN catalyst adsorbed on the cotton fabrics is introduced into the process as a functional textilematerial, the decolouration of RB4 is much faster, and 100 % decolouration is achieved in 10 minutes. Although pretreatmentof the fabric with acid and/or UV/ozone before application of MnTACN influences the amount of adsorbedMnTACN, the decolouration process is almost unaffected over time. Pre-treatment of fabric with chitosan before theapplication of MnTACN affects the final decolourisation rate and efficiency negatively, and does not act synergistically withthe MnTACN. The same functional fabric with adsorbed MnTACN can be used in at least 5 consecutive AOPs, which makesthe process more environmentally friendly and cost effective, but also opens the possibility to a continuous wastewatertreatment process.