Kinetic modeling, equilibrium isotherm, and thermodynamic studies on the removal of safranin using a new crosslinked cellulose as an adsorbent

Abstract

The requirement for environment-friendly, economical and efficient biosorbent materials for the selective removal of dyestuffs from industrial effluents becomes unavoidable. In the present work, a hydrogel based biosorbent HPC-EDTA has been fabricated and characterized by various analytical techniques including XRD, SEM, and FTIR. The biosorbent was found to be efficiently elaborated. Via an elaborative network with extensive and hydrophilic surface adsorption sites. the hydrogel exhibits high selectivity and significant adsorption capacity (~1395mg/g) for safranin from water because of electrostatical interactions and recuivable hydrogen bonding. The optimum removal of safranin was attained at pH of 7, with 25◦C, initial dye concentration of 300 mg/L, and a contact time of 40 min. The process of adsorption is best represented as a pseudo-second-order kinetic model. The adsorption equilibrium data well fitted both the Langmuir and Freundlich models with a higher correlation with the Freundlich model. Thus, the HPC-EDTA hydrogel could effectively be a promising biosorbent for environmental applications in the future.

Keywords

• kinetic models
• isotherm models
• adsorption
• cellulose
• hydrogel
• safranin
• water treatement