BTX Removal from Aqueous Solution Using Copper- and Nickel-Modified Zeolite 4A: Kinetic, Thermodynamic, and Equilibrium Studies

The purpose of the present study is to investigate the ability of zeolite 4A adsorbent modified with nanoparticles of copper and nickel to remove benzene, toluene, and xylene (BTX) from aqueous solution. The nanoparticle-modified zeolite 4A was characterized using FTIR, XRD, BET, and BJH techniques. Also, the effect of contact time, adsorbent dosage, solution temperature, and pH on the removal of BTX from aqueous solutions was investigated. Results revealed that the specific surface area for zeolite 4A increased from 0.69296 to 2.7735 m(2)/g and 2.6681 m(2)/g by modification of zeolite with copper and nickel nanoparticles, respectively. The BTX removal increased by modification of zeolite 4A with copper and nickel nanoparticles, while the removal efficiency using nickel nanoparticle-modified zeolite was more than copper nanoparticle-modified zeolite. Also, with the increase of time, adsorbent dosage, and pH and decrease of temperature, BTX removal increased. The optimal values for the contact time, adsorbent dosage, pH, and temperature were 75 min, 5 g, 10, and 25 degrees C, respectively. The adsorption kinetic results showed BTX adsorption using modified zeolite is followed by the pseudo-second-order model. The experimental results were best fitted with the Freundlich isotherm model. The thermodynamic results indicate that the BTX adsorption using modified zeolite is exothermic and thermodynamically stable.