Removal of Methylene Blue from Water by Copper Alginate/Activated Carbon Aerogel: Equilibrium, Kinetic, and Thermodynamic Studies

Abstract

Activated carbon adsorption method was the most commonly used in the flied of the sewerage treatment due to large adsorption capacity, high adsorption efficiency, convenient operation and high regeneration rate. Despite this, the poor aqueous dispersion has a potential to cause loss of the adsorbent and affect water quality. The dispersion state of the activated carbons can be controlled effectively by aerogel. In this paper, copper alginate/activated carbon (CA/AC) aerogel was prepared by using the ionic gelation method. The CA/AC aerogel was characterized by scanning electron microscope (SEM), Fourier Transform infrared spectroscopy (FTIR) and Brunauer–Emmett–Teller (BET) surface area. Methylene blue (MB) was served as the adsorbate. The effect of adsorbent dose, contact time, initial MB concentration and temperature was studied systematically on adsorption performance of CA/AC. Testing results showed that CA/AC aerogel has high BET surface area of 319.64 m2/g and high adsorption capacity of 446.43 mg/g at 303 K. The equilibrium of methylene blue removal process by CA/AC aerogel were well described by the Langmuir isotherm model and Freundlich isotherm model. The results of the thermodynamic investigations indicated that the adsorption reactions were spontaneous, exothermic and the adsorption kinetics of methylene blue on CA/AC aerogel was best fitted to the pseudo-second-order kinetic model.