Worcester Polytechnic Institute Electronic Theses and Dissertations Collection

Title page for ETD etd-050109-114725


Document Typethesis
Author NameChakraborti, Amrita
Email Address chak_amrita at yahoo.com
URNetd-050109-114725
TitleAlpha-Poly-L-Lysine As A Potential Biosorbent For Removal Of Hexavalent Chromium From Industrial Waste Water
DegreeMS
DepartmentBiology & Biotechnology
Advisors
  • Alex. A. DiIorio, Advisor
  • Theodore. C. Crusberg@wpi.edu, Co-Advisor
  • Dabiel. G. Gibson III, Committee Member
  • Keywords
  • chromium
  • poly-lysine
  • Polymer enhanced Diafiltration
  • Biosorbent
  • Date of Presentation/Defense2008-09-27
    Availability unrestricted

    Abstract

    Remediation of heavy metals from industrial effluents and ground water sources poses a significant challenge. Hexavalent chromium is one such heavy metal, prevalent in industrial wastewaters, which has been proven to be toxic to humans and other living organisms. Most of the conventional methods available for dealing with chromium are either cost prohibitive or generate secondary effluents which are difficult to deal with. The idea of bioremediation has gained much momentum over the last few decades because of its potential low cost and minimum impact on the environment. This study explored the potential for hexavalent chromium bioremediation using a synthetic cationic biopolymer alpha-poly-l-lysine (alpha-PLL) as a biosorbent. In the present research work, equilibrium batch studies were performed in a specially designed dialysis apparatus to obtain preliminary information about the adsorption capacity of the polymer. Metal uptake by the polymer was found to be maximum when the pH of chromium solution (pH 4.6) and that of poly-lysine (pH 5.7) was not changed at the beginning of the experiment. Applying the Langmuir adsorption isotherm model showed that alpha-PLL has a maximum uptake capacity of 42.2 microgram Cr/mg alpha-PLL, and a binding constant of 1.2 microgram/mL +/- 10%. The metal uptake performance of the polymer was also evaluated in a Polymer Enhanced Diafiltration (PEDF) system. The polymer-metal complex was retained and concentrated by the PEDF set up using a tangential flow filtration membrane, while the clean filtrate flowed through. When 3.4 L of 10 mg/L chromium solution in the Cr2O72- form was processed using 300 mL of 2 gm/L PLL, the concentration of chromium in the permeate reached a maximum of 0.79 mg/L. When 30 mg/L chromium solution was used, 2 L could be processed using 300 mL of 2gm/L PLL, and 7.8 mg/L chromium could be detected in the permeate in the end.

    Files
  • CHAKRABORTI.pdf

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