Rebekah Brosky
Florida Gulf Coast University, USA
Title: What is the Role of Diffuse Double Layer (DDL) Processes During Electrolytic Reduction in a Low-Oxygen Environment?
Biography
Biography: Rebekah Brosky
Abstract
Heavy metals typically accumulate in reduced bottom sediments after being discharged into waterways by industrial and municipal processes. Copper in particular is widely used as a major component of electronic devices. Cu(II), the most prevalent form of Cu in the natural environment, is highly water soluble. A laboratory experiment was conducted inorder to determine if abundance of clay in the bottom sediments of a Cu-contaminated aqueous ecosystem could enhance electrolytic reduction of the heavy metal to the less mobile (Cu(0) or Cu(I)) forms. Cu(NO3)2*2.5H2O was added to simulate a moderately contaminated system with 650 μg Cu/ml kaolinite clay-water slurry. A constant electrical potential of 1.0 V/cm was applied across platinum wire electrodes inserted into the continuously stirred system for four days while the system ORP was monitored and periodic sub-samples were taken for analysis. The electrical as well as the chemical results indicate that the quantity of Cu(II) being reduced to Cu(I), especially within the aqueous phase, is increased within the first 48 hours of experimentation by the presence of kaolinite clay up to 0.05mg clay/liter slurry. Though an electric current is necessary to initiate and sustain the non-spontaneous redox reaction, we were able to demonstrate that the clay content of the soil matrix itself may determine the subsequent efficiency of the reduction process. Under an applied current, the clay DDL behaves as capacitor for charge storage in this natural system and is aiding the heavy metal clean-up process.