Waste water, electrochemical treatment

This review article summarizes the broad area of electroorganic synthesis, (selected electroorganic synthetic reactions, with a special emphasis on those that have been commercialized or investigated in pilot plants) and selected applications of electrochemical techniques for waste-water and effluent treatment. There are a number of modern textbooks and updated reviews [4-53] of electroorganic chemistry that include much more detail on organic reactions and their mechanisms than it is appropriate to discuss here. 

The electrochemical generator is designed for both small (0.136-4.5 kg C102/day) and larger scale (0.5-27 kg/h range and more) chlorine dioxide production rates. The chlorine dioxide solution from this system is suitable for sanitizing and disinfection applications as well as waste water treatment. 

Kreysa G (1991) Electrochemical recycling and treatment process for contaminated waste-waters, Abstr KL-5-1, 42nd ISE Meeting, Montreux, Switzerland, Aug 25-30... 

Endyus kin PN, Selezenkin SV, Dyumaev KM (1983) Electrochemical treatment of waste-water from organic dye manufacturing plants, Zh Prikl Khim, 56(5) 1167 Chem Abstr 99 (1983) 76176b... 

Geer, R.D. 1978. Predicting the anaerobic degradation of organic chemical pollutants in waste water treatment plants from their electrochemical reduction behavior. In Montana University Joint Water Resources Research Center, Bozeman, MT, Completion Report No. 96... 

Comninellis C. Electrocatalysis in the electrochemical conversion/combustion of organic pollutants for waste water treatment. Proceedings of the Symposium on Water Purification by Photocatalytic, Photoelectrochemical and Electrochemical Processes. Vol. 94-19. Pennington, NJ The Electrochemical Society, 1994 75-86. 

Comninellis C, Plattner E. Electrochemical waste water treatment. Chimia 1988 42 250-252. 

Comninellis C, Pulgarin C. Anodic oxidation of phenol for waste water treatment. J Appl Electrochem 1991 21 703-708. 

Kotz R, Stucki S, Career B. Electrochemical waste water treatment using high overvoltage anodes Part I. Physical and electrochemical properties of Sn02 anodes. J Appl Electrochem 1991 21 14—20. 

Two cubic meters of a nonbiodegradable organic industrial waste water with a COD of 10 kg/m3 and a TOC of 5 kg/m3 are to be pretreated (before the biological treatment) by anodic oxidation under galvanostatic conditions (i = 1 kA/m2) using a filter press electrochemical reactor with a 20 m2 anode surface area. Consider that ... 

Since the extreme oxidizing power of the oxyl spin centers is successfully employed in waste water treatment, an application of these intermediates seems to be self-contradictory in terms of synthetic use. However, alkoxylation of hydrocarbons is a very important technical field since it allows the installation of functionalities without using the detour via halogenations. The selective introduction of functional groups on a completely nonactivated hydrocarbon has not yet been realized by BDD technology. In contrast, the direct anodic methoxylations of activated carbons exhibiting benzylic or allylic moieties can be performed at BDD anodes. The results obtained with BDD electrodes are quite similar to those when graphite serves as anode [57]. The anodic synthesis of benzaldehyde dimethyl ketals is industrially relevant and performed on the scale of several thousand tons. A detailed study of the anodic methoxylation of 4-tert-butyltoluene (10) at BDD was performed [58]. Usually, the first methoxylation product 11 and the twofold functionalized derivative 12 are found upon electrochemical treatment (Scheme 5). 

Since boron-doped diamond electrodes are commercially available, most of these suppliers offer a wide variety of electrolysis cells. Modular electrochemical cells equipped with BDD electrodes have been reported in detail [122]. However, most of these cells were designed for waste water treatment and were not suitable for electrosynthesis in organic media. Electrolysis cells for synthetic purposes designed for a small volume made of organic-compatible materials are required. Additionally, any contact of the support with the organic electrolyte has to be strictly eliminated in order to avoid the corrosion. Most BDD electrodes are on a silicon support which causes eventual loss of the BDD electrode by the brittle nature of crystalline silicon. Consequently, the material used for sealing has to be inert but soft enough to avoid friction of the silicon support. The available BDD... 

Kirk, D., Sharifian, H. and Foulkes, F. R. (1985) Anodic oxidation of aniline for waste water treatment. J. Appl. Electrochem. 15, 285-292. 

Stucki, S., Kotz, R., Career, B. and Suter, W. (1991), Electrochemical waste water treatment using high overvoltage anodes part II Anode performance and applications. J. Appl. Electrochem., 21(2) 99-104. 

BDD electrodes are commonly used for electrochemical (waste) water treatment because of their efficient ability for total organic carbon (TOC) removal. The aim to carry out selective electrochemical processes seems therefore to be self-contradictorily. 

Iniesta, J., Michaud, P.A., Panizza, M. and Commninellis, Ch. (2001a) Electrochemical oxidation of 3-methylpyridine at a boron-doped diamond electrode applications to electroorganic synthesis and waste water treatment. Electrochem. Commun. 3, 346-351. 

Polcaro, A.M., Vacca, A., Palmas, S. and Mascia, M. (2003) Electrochemical treatment of waste-water containing phenolic compounds Oxidation at boron-doped diamond electrodes. J. Appl. 

The formation of gas bubbles in a porous medium affects, e.g., the performance of anaerobic granular sludge particles containing entrapped gas (waste-water treatment), or the performance of electrochemical reactors where a gas (hydrogen, oxygen, chlorine) evolves inside a porous electrode. A related problem is that of bubble nucleation on structure surfaces, which can be as varied as specially designed surfaces for enhanced nucleate boiling heat transfer, or the... 

---