Investigation of Effective Removal of Auramine O Dye by Pyracantha Coccinea Biosorbent: Isotherm and Kinetics

Abstract

In this study, the effect of biosorbent dosage (0.1-0.4 g/L), dye pH (3.0-9.0) and initial dye concentration (50-500 mg/L) on synthetic Auramine O (AU-O) dye removal of biosorbent produced from Pyracantha coccinea (PC) plant by physical modification was investigated and the dye removal behavior of the biosorbent was investigated by kinetic and isotherm experiments. In the batch experiments, it was observed that as the adsorbent quantity was raised from 1 g/L to 4 g/L at a consistent dye concentration, the adsorption capacity declined from 69.25 mg/g to 22.73 mg/g. The adsorption capacities of AU-O dye at concentrations of 50 mg/L and 100 mg/L were determined to be 22.350 mg/g and 72.35 mg/g at 200 mg/L, respectively. The reason why there was no significant increase in adsorption capacity at higher dye concentrations (250-500 mg/L) was that at constant amount of biosorbent, the change in adsorption capacity was minimal since the active sites of the biosorbent reached saturation. The adsorption capacity was determined to be 26.512 mg/g, 38.74 mg/g, and 44.07 mg/g at pH:3.0, pH:4.88, and pH:7.0, respectively. It has been determined that the adsorption capacity achieved at pH 9.0 (44.21 mg/g) was nearly equivalent to the adsorption capacity observed under neutral pH conditions. The adsorption mechanism is best explained by the Langmuir isotherm (qm:123.10 mg/g and R2:0.990) and the pseudo-second-order kinetic models (R2: 0.985) in the adsorption isotherm and kinetic research.