Removal of bromocresol green from aqueous solutions using chitin nanofibers

Dyes in wastewater generate one of the main sources of environmental pollution, and treatment of this pollution is absolutely ncessary for protection of the environment. New economical and environmentally friendly approaches are needed to remove dyes from aqueous solutions. The purpose of this study was to use chitin nanofibers, as a valuable natural material, to remove bromocresol green dye. The effects of effective variables such as pH (2-7), adsorbent dosage (0.25-2.5 gram), initial concentration (0.2-2 mg.l-1), temperature (20-45 °C) and contact time (5-30 min) were investigated for color removal. The results showed that color adsorption is pH dependent and pH=6 was selected as the optimal value. Given that at the concentration of 0.4 mg.l-1, 92.75% of the color was removed, this concentration was chosen as the optimal case. By taking into account the cost of the absorbent, 1.5 gram was selected as the optimal dosage for bromocresol green. A contact time of 10 minutes at 25°C was considered as the best for these two parameters, which indicates the short duration of this treatment. One way anova and Duncan test in Excel and SPSS software indicated a significant effect of the parameters on removal of dye. The results showed that chitin nanofibers have significant influence on the removal and reduction of bromocresol green from aqueous solutions, and thus wastewaters containing other colors. This process can be replicated in diluted wastewater treatments in textile industry without requiring high pressures and temperatures.