A Novel Approach to Investigate Adsorption of Crystal Violet from Aqueous Solutions Using Peels of Annona squamosa

Abstract

An effective and economical adsorbent was prepared from the peels of Annonasquamosafor the removal of crystal violet from aqueous solutions. Adsorption studies were carried out using batch experiments. The dependence of initial dye concentration, pH, contact time, particle size and temperature on the adsorption process was studied. The crystal violet was found to be electroactive and hence electrochemical studies were also performed. The study showed that the equilibrium was achieved within 60 min for the different initial concentrations (10 to 30 mg.l ). The equilibrium adsorption data were analyzed using various isotherm models 1 and they were found to fit Langmuir, Freundlich, Temkin and Harkins-Jura isotherm models in varying orders of magnitude. The maximum dye adsorption capacitiesfor cyclic voltammetry and spectral studiesat 303 K were found to be 5.6818 × 10 A.g (in terms of current)and 5×10 mg.g (in terms of weight),respectively. The data 41 4 1 suggested that the adsorption kinetics was best represented by pseudo-second order kinetic model. The thermodynamic parameters including G, H and S for the adsorption process have also been evaluated using which it was concluded that the process of adsorption was spontaneous and endothermic. The cyclic voltammetricand spectral studies yielded similar results. Furthermore, statistical analysis also showed the absence of any significant difference between the two methods.