Laboratory Experiments on Electrochemical Remediation of the Environment. Part 2: Microscale Indirect Electrolytic Destruction of Organic Wastes

Abstract

The objective of this experiment is to destroy, at the microscale level, a sample of surrogate organic waste by generating a powerful oxidizer at the anode of an electrochemical cell. This generated species oxidizes the waste to harmless products. The oxidizer can then be regenerated and recycled. Specifically, this experiment utilizes a redox mediator with a high standard potential (i.e., the Co (III/II) couple, E° = 1.82 V) to destroy a surrogate organic waste (e.g., glycerin or acetic acid) by converting it into CO2 and water. Students can observe the end of the reaction signaled by a color change of the electrolytic medium (from pink to gray-light purple) as well as the evolution of CO2 which precipitates CaCO3 from a Ca(OH)2 solution. The Co(II) solution and the electrodes can then be reused.

Treatment of orange II azo-dye by electrocoagulation (EC) technique in a continuous flow cell using sacrificial iron electrodes

“…Overall : Fe 0 + 2H 2 O Fe(OH) 2(s) + H 2(g) (10) The gelatinous suspension of Fe(OH) n(s) formed as a result of this electrochemical process can remove the pollutants from wastewaters, either by complexation or by electrostatic attraction followed by coagulation and flotation [43]. However, examination of the Pourbaix diagram (Eh-pH diagram) [44] reveals that Fe 3+ ion is stable only in a very oxidizing acidic medium, whereas the Fe 2+ ion is stable over relatively a large Eh-pH range.…”

Optimization of the electrocoagulation process for the removal of copper, lead and cadmium in natural waters and simulated wastewater

“…Optimization of color removal in wastewater (Iba´n˜ez et al, 1998), treatment of wastewater with oils (Iba´n˜ez et al, 1995) and destruction of organic residuals has been accomplished using electrocoagulation (Iba´n˜ez et al, 1997). Vik et al (1984) studied the efficacy of electrocoagulation in removal of humic acid from potable water.…”

Teaching the Tenets and Applications of Hydrodynamic Voltammetry Using an Inexpensive, User-Friendly, Hands-on Setup with a Rotating Platinum Electrode in Aqueous Solution to Fortify Student Comprehension of Voltammetry

“…Concepts of electro-analytical chemistry are pivotal for all science, engineering, and technology students in view of widespread applicability in energy devices, corrosion prevention methods, and biomedical sensors. − Voltammetry is a major branch of electro-analytical chemistry and is included in most undergraduate and postgraduate curricula to introduce its essence to students. A significant number of articles, classroom activities, communications, demonstrations, and laboratory experiments have been reported in recent years that enhance the understanding of voltammetry. − Yet there seems to be a dearth of simplified teaching aids that would fortify the concepts of hydrodynamic voltammetry (HV) and applications stemming from them.…”