Synergistic effect of adsorption and photo-catalysis on the removal of hazardous dyes using steam exploded banana fiber derived micro-cellulose

Abstract

The utilization of banana fiber derived from micro-cellulose (MC) was exploited as a supporting material for advanced oxidation process (AOP) on the degradation of methylene blue and methyl violet dyes in the presence of H2O2-UV in aqueous medium for the first time using green chemistry protocols. Additionally, it was also effectively utilized for the adsorption of methylene blue dye using addition of H2O2 in the presence of sunlight. The MC powder was fabricated using an acid alkali process from the pseudo-stem of a banana tree. The as-fabricated MC powder was systematically characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectrometer (EDX), and zero point charge (pHzpc). The AOP assisted degradation of dye molecules was monitored by using calorimetric techniques as a function of dye concentration and pH in a batch reactor. In a short period of time, the maximum degradation efficiency of 98 % of methylene blue was achieved using MC powder assisted H2O2 under UV irradiation at a minimum irradiation time of 120 min at pH 7.0 using dosage of 0.2 g/L. However, in the absence of UV light, the degradation efficiency of MC powder assisted H2O2 was only about 5–10 % without UV light irradiation. The dye removal was studied as a function of various operational parameters such as pH (3–11), catalyst dose (0.2–0.6 g/L), and initial dye concentration (100–400 mg/L). In the presence of H2O2-sunlight and 0.2 g/L of dosage at pH 7.0 at a minimum contact time of 120 min, MC fiber showed maximum adsorption capacities of 98% and 85% for 100 mg/L and 400 mg/L of methylene blue concentrations. According to the obtained data, the adsorption of methylene blue dye on MC follows the Freundlich isotherm model (R2 = 0.9886) and pseudo-first-order kinetic model (R2 = 0.9596) due to the higher regression coefficients. This process of dye degradation and adsorption process is a novel one and environmentally benign for an effective removal of hazardous dyes.