Volume No. 10 Issue No.: 3 Page No.: 392-406 Jan-Mar 2016

 

STATISTICAL OPTIMIZATION OF ADSORPTION VARIABLES FOR BIOSORPTION OF CHROMIUM (VI) USING CARROT BASED ADSORBENTS EQUILIBRIUM AND KINETIC STUDIES

 

Desai S.M., Charyulu N.C.L.N, Behara D. K. and Satyanarayana S. V.

1. Department of Chemical Engineering, Dayananda Sagar College of Engineering, Bangalore (INDIA)
2. Department of Chemical Engineering, Chaitanya Bharathi Institute of Technology, Hyderabad (INDIA)
3. Department of Chemical Engineering, Jawaharlala Nehru Technological University, Anantapur, Anantapuramu (INDIA)

 

Received on : October 10, 2015

 

ABSTRACT

 

Hexavalent chromium pollution is the most substantial difficulties faced today due to quick industrialisation and heavy usage of chromium in industrial process. The present study aimed to employ low-cost agro waste biosorbent from carrot (Daucuscarota) with crude, HCl treated and NaOH treated forms for the removal of hexavalent chromium ions from aqueous solution. All the biosorption experiments were carried out in batch mode to optimize process parameters using response surface methodology. Based on central composite design, quadratic model was developed to correlate the variables to the response. Through Analysis of Variance (ANOVA), it was observed that, pH and initial concentration were significant for all the adsorbent. Among all the adsorbents tested, HCl treated carrot removed a maximum of 98.9% with highest initial metal concentration of 122.72mg/l, at pH of 2.72, temperature of 42.9C with lowest biomass loading of 2.8 g/100 ml compared to other two adsorbents. The effect of parameters namely, initial metal ion concentration, pH, temperature, biomass loading on chromium removal efficiency were studied. The experimental data fits well to Langmuir, Freundlich and Temkin isotherms with Regression coefficient (R2) more than 0.94 for all the adsorbents. The HCl treated carrot had maximum monolayer adsorption capacity of 109.89 mg/g and a separation factor of 0.385 indicating it as best adsorbent among the three tested adsorbents. Pseudo second order kinetics model fits well to the experimental data for all the three adsorbents.

 

Keywords : Biosorption, Daucuscarota, Hexavalent chromium, ANOVA, Isotherms and kinetics

 

 

BACK