Liquid Phase adsorption kinetics and equilibrium of toluene by novel modified-diatomite

Abstract

The adsorption equilibria of toluene from aqueous solutions on natural and modified diatomite were examined at different operation parameters such as pH, contact time, initial toluene concentration was evaluated and optimum experimental conditions were identified. The surface area and morphology of the nanoparticles were characterized by SEM, BET, XRD, FTIR and EDX analysis. It was found that in order to obtain the highest possible removal of toluene, the experiments can be carried out at pH 6, temperature 25°C, an agitation speed of 200 rpm, an initial toluene concentration of 150 mg/L, a centrifugal rate of 4000 rpm, adsorbent dosage = 0.1 g and a process time of 90 min. The results of this work show that the maximum percentage removal of toluene from aqueous solution in the optimum conditions for NONMD was 96.91% (145.36 mg/g). Furthermore, under same conditions, the maximum adsorption of natural diatomite was 71.45% (107.18 mg/g). Both adsorption kinetic and isotherm experiments were carried out. The experimental data showed that the adsorption follows the Langmuir model and Freundlich model on natural and modified diatomite respectively. The kinetics results were found to conform well to pseudo-second order kinetics model with good correlation. Thus, this study demonstrated that the modified diatomite could be used as potential adsorbent for removal of toluene from aqueous solution.

Separation and Purification of Two Saponins from Paris polyphylla var. yunnanensis by a Macroporous Resin

“…The Freundlich isotherm model equation is expressed as: where Q m indicates saturated adsorption capacity (mg/g); K L represents adsorption energy correlation constant; K F is the Freundlich adsorption capacity coefficient; and 1/n is the correlation coefficient of resin capacity [ 37 , 38 ].…”

Formation of Palygorskite Clay from Treated Diatomite and its Application for the Removal of Heavy Metals from Aqueous Solution

“…The other two vibrations at around 1023 cm −1 and 465 cm −1 were related to the asymmetric stretching vibration mode of siloxane (Si-O-Si) [27]. The peak at 786 cm −1 was attributed to Al-O-Si stretching vibration according to the clay minerals in diatomite [28].…”

Enthalpic and Liquid-Phase Adsorption Study of Toluene–Cyclohexane and Toluene–Hexane Binary Systems on Modified Activated Carbons

“…Although adsorption in liquid phase has been widely used in the processes mentioned at the beginning of the introduction, it has been studied mainly for the aqueous phase [ 17 , 18 , 19 , 20 ], but little has been investigated about liquid phase adsorption for hydrocarbons when the solvent is another nonpolar organic substance [ 18 ], due to the research found is related to the usage of water as a solvent [ 17 , 18 , 19 , 20 ]; therefore, the study of systems of this type is interesting, since low-molecular-weight hydrocarbons are within the Volatile Organic Compounds (VOCs) which, due to their characteristics, can be in the environment in the gas and liquid phase.…”

“…So, the interesting aspect of this work is that nonpolar solutions are evaluated; this is a field that is not so commonly studied because it is more usual to find research that investigates aqueous systems [ 17 , 18 , 19 , 20 ].…”