Effect of Brij 35 and saponin surfactants on adsorption of diethylstilbestrol as an emerging estrogenic contaminant by clinoptilolite in batch and fixed-bed column experiments

Authors : Reyhaneh SADDI, Reza FAZAELI, Leila VAFAJOO, İraj NASER

Pages : 778-801

View : 18 | Download : 9

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :In this study, natural clinoptilolite was modified by saponin and Brij 35 surfactants to remove diethylstilbestrol insert ignore into journalissuearticles values(DES); from wastewater in batch and continuous systems. The optimum pH, amount of adsorbent, contact time, and temperature were 11, 10 g/L, 12 h, and 35 °C, respectively, for the process. The equilibrium data agreed well with the Langmuir isotherm for natural clinoptilolite insert ignore into journalissuearticles values(NC);, natural clinoptilolite modified by Brij 35 insert ignore into journalissuearticles values(NC-Brij);, and natural clinoptilolite modified by saponin surfactants insert ignore into journalissuearticles values(NC-saponin); compared to other isotherms. The maximum adsorption capacities resulting from the Langmuir isotherm for NC, NC-Brij, and NC-saponin were 8.012, 23.64, and 39.525 mg/g, respectively. Fixed-bed column experiments were performed under various operational conditions to evaluate the performance of the adsorbent bed breakthrough curve. The lumped method solves bed equations to determine the axial dispersion coefficient insert ignore into journalissuearticles values(Dz); and overall mass transfer coefficient insert ignore into journalissuearticles values(Koverall); parameters. Comparison of the kinetic models indicated that the DES adsorption process was well described by the intraparticle diffusion model for NC, pseudo-second-order and fractional power kinetic models for NC-Brij, and pseudo-second-order model for NC-saponin. The negative Gibbs free energy and positive enthalpy changes for NC, NC-Brij, and NC-saponin confirmed that the removal reaction of DES was spontaneous and the adsorption was endothermic, respectively.
Keywords : Pharmaceutical contaminant of diethylstilbestrol, saponin and Brij 35 surfactants, natural clinoptilolite, batch and fixed bed studies