Adsorption of methylene blue onto sonicated sepiolite from aqueous solutions

Abstract

The aim of the present study is to enhance the methylene blue (MB) adsorption of sepiolite by ultrasonic treatment. The natural sepiolite was pretreated by sonication to improve the surface characteristics and enhance the dye uptake capacity. Sonication process resulted in a significant increase in the specific surface area (SSA) of sepiolite. The FTIR spectrum of the sonicated sepiolite indicates that the tetrahedral sheet is probably distorted after sonication process. The effect of various parameters such as sonication, pH, initial dye concentration and temperature on dye adsorption has been investigated. The adsorbed amount of MB on sepiolite increased after sonication as well as with increasing pH and temperature. The experimental data were evaluated by applying the pseudo-first- and second-order, and the intraparticle diffusion adsorption kinetic models. Adsorption process of MB onto sepiolite followed the pseudo-second-order rate expression. The experimental data were analyzed by Langmuir and Freundlich isotherms, and found that the isotherm data were reasonably well correlated by Langmuir isotherm. Maximum monolayer adsorption capacity of sepiolite for MB increased from 79.37 to 128.21 mg/g after the sonication. Various thermodynamic parameters, such as Delta G(0), Delta H(0) and DeltaS(0) were calculated. The thermodynamics of MB/sepiolite system indicated spontaneous and endothermic nature of the process. Adsorption measurements showed that the process was very fast and physical in nature.

Removal of Basic Red 18 onto modified sepiolite: Equilibrium, adsorption kinetics and thermodynamic studies

“…[1]. A number of investigations on sepiolite have been reported and continue to be carried out intensively [1,[24][25][26][27][28]. In this study, the removal of BR 18 onto KF/sepiolite was investigated.…”

“…Sepiolite is a natural clay mineral with formula of Mg8Si12O30(OH)4(OH2)4·8H2O [24,25]. Sorption of sepiolite is higher than the other clay.…”

Mussel inspired green synthesis of silver nanoparticles-decorated halloysite nanotube using dopamine: characterization and evaluation of its catalytic activity

“…Recently, applications of organic pollutants, such as dyes and derivatives of phenol, are escalated due to extensive use in various field such textile, paper, leather industries and the uncontrolled discharge of these organic pollutants into main stream water leads to environmental hazardousness which in turn affects the aquatic life as well as unsuitable esthetic facet (Almeida et al 2009;Choudhary et al 2017;El Qada et al 2008;Küncek and Şener 2010;Venkatesham et al 2014). Moreover, the presence of the organic dyes in the ground water is unsuitable for irrigation and drinking.…”

Kinetics Studies on the Process of Zn Removal from Wastewater Using Ultrasonically Activated Sorbents

“…In order to increase the exchangeability potential of the mineral clays by modifying their chemical composition and crystal structure, they are submitted to different chemical and physical treatments, such as hydrothermal, acid and alkaline activation [1][2][3][14][15][16][17] . Recently, ultrasonic energy has also been applied for activating clays [18][19][20][21][22] . The purpose is to improve their surface characteristics by reducing the particle size due to a delamination effect and by breaking of layers in the other directions, while the crystalline character is retained.…”