Optimization, isotherm and kinetics studies of azo dye adsorption on eggshell membrane

Abstract

Eggshell membrane (ESM) was used as an adsorbent for adsorption of reactive red 195 (RR195) and reactive black 5 (RB5) dyes from aqueous solutions. The experimental conditions were optimized via batch system experiments for maximum azo dyes removal. Adsorption of the dyes was pH dependent highly, and the maximum adsorption of RR195 and RB5 occurred at pH 3.0 and 2.0, respectively. For both dyes, the adsorption process was seen to be obeyed pseudo-second order kinetic and the Langmuir isotherm models. Maximum adsorption capacities (Q max) of ESM for RR195 dye and RB5 were found as 76.9 and 333.33 mg g-1 , respectively. The thermodynamic parameters were calculated and the adsorption of the dyes was found to be as exothermic and spontaneous. Moreover, the structural characterization of the ESM was performed by FTIR and SEM analysis.

Removal of Acid Yellow 17 from Textile Wastewater by Adsorption and Heterogeneous Persulfate Oxidation

“…The adsorption may be less with an increase in the diffusion rate of dye molecules and Brownian movement due to increasing temperature. Moreover, an increase in the solubility of the dyes may cause low COD removal (Dincer et al 2019 ). The temperature may not have been able to create active regions on PAC surface since PAC is already activated at high temperatures.…”

“…The reason for this may be using an adsorbent commercially prepared and activated at high temperatures. Dincer et al ( 2019 ) have stated that H 2 bond between adsorbent and dye molecules may be broken as temperature increases (Dincer et al 2019 ).…”

“…The fact that pH value of PAC used as an adsorbent is 10.29, in other words, it is alkali, may have made acidic conditions more favorable for color removal. Because it is stated that electrostatic attraction forces increase for adsorption of dyes under acidic or near-neutral conditions (Dincer et al 2019 ). pH of AY17 dye is 5.82, and it is near-neutral value.…”

“…The electrostatic driving forces between the adsorbent and the dye molecules may be increased as a result of the increase in the number of the same charged groups on the adsorbent under alkali conditions. Hydroxyl (OH − ) ions may be also prevented the adsorption of dye ions under alkali conditions (Dincer et al 2019 ). One reason for low efficiency in alkali conditions may be that basic dyes could not be dissolved completely (Pimol et al 2008 ).…”

Phenol removal from synthetic wastewater with powdered activated carbon: Isotherms, kinetics and thermodynamics

“…Furthermore, the solubility of phenol may be increased with increasing temperature and the interaction of the pollutant with the adsorbent (physical bond) may be reduced. In other words, Brownian movement of phenol molecules may be increased [17].…”