Effluents resulting from the frequent use of industrial azo dyes in textile operations have posed great toxicological impacts on man and the environment. The limitations of conventional treatment infrastructure necessitate the use of rapid Fenton-mediated catalytic systematic process to tackle the attendant treatment limitations. The study applied in situ Fenton-mediation process with constructed low power UV-LED reactor for rapid catalytic treatment of dye-laden effluent using enhanced acid and alkali TiO2-nanoparticles (Nps) (1–5%, i.e. 1–5 M) at definite experimental conditions, respectively. A comprehensive instrumental study was done to access the morphological, functional and elemental constituents of these nanocatalysts. The performance of the respective catalyst was evaluated using methylene blue (MB) dye at definite experimental conditions of pH, dosage, concentration and irradiation time. The results revealed a mesoporous structural nanocatalyst with increasing surface area after enhanced modification. The optimal experimental conditions of pH and concentration were recorded as 5 and 10 mg/L, respectively. While the most efficient nanocatalyst was 3 wt% alkali-modified TiO2 (3% Ak-TiO2) having a degradation efficiency of 89.15% at 90 min of irradiation using 50 mg dosage in contrast to higher irradiation time and catalyst dosage for other catalysts.