Optimization of solid state fermentation of banana peel for removal of crystal violet dye from aqueous solution

Abstract

Problems originating from the dyeing industry wastewater still continue to be an environmental issue. Crystal Violet is a dye that has mutagenic properties and is toxic to mitosis. Banana peels have been widely reported for their capacity as potential biosorbents to remove dyes and metals. This study aims to increase the biosorption capacity of banana peels through SSF using Aspergillus niger. The potency of the banana peel of unfermented and fermented products were studied for the decolorization of Crystal Violet dyes. The effect of fermentation on physical and chemical characters was observed using SEM and FTIR. The effect of parameters such as initial pH (4.0-9.0), initial dye concentration (10-60 ppm), biosorbent dose (0.1-1 g/1) and contact time (15-150 min) were examined. Microscopy revea1ed that SSF disrupted the surface structure and infrared spectrophotometer (FTIR) showed the addition of functional groups. Maximum dye removal was observed at pH 7, contact time 120 min, and biosorbent concentration of 0.5 gram for unfermented banana peel; while the optimum SSF product was at pH 7, contact time was 30 minutes, and the concentration of biosorbent was 0.2 gram. The adsorption mechanism is physical for both non-fermented and fermented biosorbents, as explained by the Freundlich isotherm model with a regression coefficient (R2) of 0.9396 and 0.9232, respectively.