Sorption studies of Cr (VI) ions from synthetic waste water using chitosan embedded in calcium alginate beads

Abstract

In current scenario, heavy metal stains of aquatic media have become a solemn ecological issue for which much concern has been expressed. These heavy metals include chromium, lead, mercury, arsenic, and cadmium. Industrialization, agricultural activities, the rapid growth of the global population, excessive use of chemicals, and uncontrolled urbanization are the main causes of heavy metal pollution. The excellent adsorption behavior of Chitosan and its modifications to various toxic heavy metals from aqueous solutions has garnered a lot of attention over the past few decades. In the present work Chitosan and immobilized Chitosan were used to compare the amount of chromium (VI) removal by altering limiting variables like Cr VI concentration, adsorbent loading, Hydrogen ion concentration and time of contact. Kinetic studies were also studied along with the isotherm models like Langmuir, Freundlich and Temkin models to analyze the experimental data and understand the adsorption performance. The efficiency of the adsorbents was checked by carrying out reusability studies by subjecting the adsorbents for repeated cycles of sorption studies. Results revealed that the immobilized biopolymers exhibited higher sorption capacity of 12.7 mg/g whereas the unmodified Chitosan exhibited 7.3 mg/g and also the efficiency of the immobilized biopolymers did not decrease with 2 – 3 cycles.