Keratin Protein Nano-fiber for Removal of Heavy Metals and Contaminants
- PDF / 1,671,620 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 93 Downloads / 157 Views
Keratin Protein Nano-fiber for Removal of Heavy Metals and Contaminants M. Misra & P. Kar, G. Priyadarshan Department of Metallurgical & Materials Engineering, University of Nevada Reno, Reno, NV 89557, USA Email: [email protected] Carlo Licata, Maxim LLC, 1015 North Lake Avenue, Pasadena, CA 91104, USA Email: [email protected] ABSTRACT Keratin protein fiber (AKFTM) is a renewable source of biosorbent that can be used for filtration of heavy metal and nanosize contaminants. The major composition of keratin fiber is the structured protein micofibril, consisting of numerous nanosized pores. The combination of nanostructure and metal binding capacity protein sites make it an ideal material for removal of heavy metals from solutions. The mechanism of heavy metal uptake onto keratin protein involves a combination of several steps such as adsorption, precipitation, and ion exchange. Keratin protein has good tensile strength and is stable over a wide pH range. INTRODUCTION & BACKGROUND Conventional methods for removing heavy metals from contaminated solutions include chemical precipitation, carbon adsorption, membrane separation, microfiltration and the use of ion exchange resins. Many of the existing technologies for the removal of heavy metals from wastewaters are unable to achieve the low final concentrations required by new regulations. Furthermore, many existing treatment processes merely convert aqueous metal ions into solid sludges, which require costly landfill disposal. Biosorption, a relatively simple metal adsorption process, can meet the progressively stricter environmental discharge criteria. The term "biosorption" is used to describe the accumulation of metal ions by adsorption and/or ion exchange from solutions by materials of biological origin, particularly microorganisms, plant biomass and animal cells and extracts [1]. Thus the potential use of materials of biological origin in the treatment of heavy metal-contaminated wastewaters is of special importance. Organisms such as algae, bacteria, fungi, and yeasts have proved to be potential metal sorbents [1]. Animal fibrous proteins such as eggshell membrane, wool, elastins, and fish shells are ideal materials and have shown strong metal binding capacities. Avian keratin fiber, also a fibrous protein derived from feathers of chicken, was found to accumulate precious metal ions (including gold and platinum) selectively from their dilute aqueous solutions in high yield and in short contact time [2,3]. Many biosorption processes are under development or have been developed for application in removing metal contaminants from solutions. Some important processes are phytoremediation and immobilization using different bacteria and fungus [4]. U2.1.1
Keratin fibers used in this study are derived from chicken feathers after a series of processing steps in which the quill fraction is separated from the feather [5]. Keratin protein fibers are stronger and more adsorbent than other fibrous materials. The scanning electron microscopic (SEM) and atomic force microscope (
Data Loading...
