Adsorptive removal of azo dye in a continuous column operation using biosorbent based on NaOH and surfactant activation of Prunus Eulcis leaves

Abstract

The adsorption of Acid Blue 113, an azo dye, from aqueous solution using biosorbent obtained from NaOH and surfactant activation of waste biomass of Prunus dulcis has been studied in the present work in column operation. The effect of various operating conditions as depth of biosorbent in the bed, influent concentration, flow rate and salt concentration on the extent of adsorption and the breakthrough characteristics have been investigated. The obtained breakthrough data was applied to different models to check the fitting using linear and nonlinear regression analysis also obtaining the model parameters for best fitting models. Error analysis using root mean square error function was performed to predict the best model fitting in terms of matching experimental values to model predicted values, closer values of correlation coefficient to unity and least error values. Yoon Nelson and Thomas models were found to be in better agreement to the obtained breakthrough data. Maximum uptake capacity was established as 59.54 mg/g for the operation with 100 mg/L as the influent dye concentration at the established optimum flow rate of 6 mL/min. Desorption and subsequent re-usability studies conducted for three cycles using ethanol as the desorbing agent confirmed the effectiveness of synthesized biosorbent for dye removal in multiple cycles as only slight decrease in biosorption capacity was observed from 52.50 mg/g for first cycle to 49.42 mg/g for third cycle of reuse. Extent of elution (%) was also found to marginally decrease from 98.59% for first cycle to 83.81% for third cycle of reuse. Overall, the column study clearly established that synthesized biosorbent is a promising adsorbent to treat Acid Blue 113 containing dye effluent in a continuous operation.