Synthesis, characterization and application of gelatine and dithiocarbamylated chitin

Abstract

Introduction: Gelatin or gelatine is a translucent, colorless, flavorless, and biodegradable material obtained from collagen present in animal body parts, such as skin, bones, and connective tissues of animals, e.g., domestic cattle, chicken, pigs, and fish. It is a mixture of peptides and proteins obtained by acid and alkaline processing of collagen and is commonly used as a gelling agent in food, pharmaceuticals, photographic films and papers, and cosmetics. Dithiocarbamates (DTC) are well known adsorbents (1-2). We reported preparation and characterization of dithiocarbamylated chitin (CHDTC) in a previous communication (3). CHDTC was found to possess good adsorption capacity, but recovery of adsorbent was not convenient. Therefore, it was envisaged to blend CHDTC with gelatine to not only enhance adsorption capacity but enable reuse of adsorbent also. Methods: Gelatine was blended with CHDTC and polyvinyl alcohol (PVA) to prepare an asymmetric membrane (AMCG), which was characterized by FTIR spectral analysis, powder X-ray diffraction measurements and scanning electron microscopy. Results & Discussion: Adsorption of crystal violet dye from its aqueous solution in 5 to 30 mg/L concentration range by AMCG was investigated using ultraviolet spectrophotometric measurements. Adsorption isotherm study indicated that Langmuir equation fitted better than the Freundlich, Temkin and Dubinin-Radushkevich equations, indicating adsorption process mainly to be monolayer. Adsorption kinetics studies suggested pseudo second order kinetics. AMCG was found to be very efficient adsorbent and maximum adsorption capacity was found to be 500 mg/g for crystal violet. Adsorption was studied at pH 4, 7 and 9. Adsorption was most rapid at pH 9 and almost 95% of crystal violet was observed within 1 h. Further, four adsorption/desorption cycles were followed, which clearly indicated AMCG to be a potential adsorbent for recycling of water from industrial effluents. Conclusions: AMCG is a suitable adsorbent for recycling of wastewater especially from industrial effluents. It shows high adsorbent capacity and fast removal of crystal violet as a model pollutant. Monolayer adsorption process enables recycling of adsorbent and recovery of the valuable compounds/ materials from effluents. Keywords: Recycling of water, Gelatine, Dithiocarbamylated chitin, Dye adsorption. Acknowledgment: Authors are thankful to Central Instrumentation Facility Laboratory, Govt. Science College, Jabalpur for XRD and FTIR spectral analysis.