Document Type

Thesis

Date of Award

5-2024

School/College

College of Science, Engineering, and Technology (COSET)

Degree Name

MS in Biology

Committee Chairperson

Jason Rosenzweig

Committee Member 1

Daniel Vrinceanu

Committee Member 2

Shishir Shishodia

Committee Member 3

Audrey Player

Committee Member 4

Gary Katz

Keywords

Acid wash, Biosorption, Escherichia coli, Extraction, Lithium, Total dissolved solid

Abstract

Lithium (Li) is a very valuable metal that is used across several industries including ceramics, glass, batteries, pharmaceuticals, and polymers. However, in recent years, the global demand for Li and its market price have increased considerably, due to its application as a critical component in the production of rechargeable Li-ion batteries and energy storage systems that are used in electric vehicles and a variety of electronic devices. Although Li occurs as a mineral in hard rocks and salt brines, substantial amounts are found in our environment as part of industrial wastes and oil-field wastewaters. Despite its importance, Li is also harmful and poses a risk to the environment. Besides, the conventional (chemical and physical) methods that are used today for its removal, such as solvent extraction and acid leaching, require high energy consumption and produce toxic by-products, posing additional environmental and economic challenges. Alternatively, the use of bacteria for Li extraction has been proposed as a viable, non-toxic, and cost- effective alternative. In this study, the potential of using Gram-negative Escherichia coli, and Gram-positive Bacillus subtilis and Bacillus cereus as biosorbents for Li was explored. Results indicate that all three bacterial species tested were capable of absorbing Li to varying degrees from aqueous solutions. However, E. coli had the highest and most consistent absorption capacity and was selected for further investigation. Amounts of total dissolved solids (TDS) and Li, analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-OES), methods were obtained in this study. In a kinetic study of Li biosorption, most Li-binding occurred within the first 24 h and slowed down until maximum biosorption was attained following 72 h, our experimental endpoint. The biosorption capacity for E. coli ranged from 60% to 43% depending on initial Li concentrations in solution. Also, the optimal pH for E. coli biosorption was found to be between pH 6-6.5. Recovered/eluted absorbed Li was measured following a 12 h mild-acid solution (distilled H2O adjusted to pH 4 with HNO3) wash of the Li-bound biomass membranes.

Download

Share

COinS