Electrochemical Treatment of Mixed and Hazardous Waste

Dziewinski, J.; Marczak, S.; Nuttall, Eric; Smith, Wayne H.

doi:10.1557/proc-412-509

Cited by 3 publications

(3 citation statements)

References 4 publications

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“…15,16 Most of them use sulfate medium with precise pH adjustment and efficient solution mixing. The current efficiency of electrolysis processes may be good ( >80%) and the energetic consumption is moderate (1Á6 kWh/kg of cadmium).…”

Section: Electrowinning Of Cadmiummentioning

confidence: 99%

Cadmium recovery and recycling from chemical bath deposition of CdS thin layers

Malinowska

Rakib

Durand

2002

Progress in Photovoltaics

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Cadmium sulfide thin layers for polycrystalline solar cells are produced by chemical bath deposition (CBD). This process generates wastes containing mainly ammonia and cadmium. We have implemented and described in a previous paper a process to recover 90% of ammonia and to confine cadmium as a cake which is a mixture of cadmium sulfide and cadmium cyanamide. The present paper concerns cadmium recycling to the CBD step. The cake is first dissolved in a moderate sulfuric acid solution 0Á2-0Á5 mol/l mixed with hydrogen peroxide (about 1 mol/l). This last component must be used in large excess (molar ratio H 2 O 2 /Cd 5 5) and must be completely removed from the solution before recycling or cadmium electrowinning. Hydrogen peroxide decomposition is electrochemically catalyzed by platinized platinum immersed into the solution. The resulting solution contains cadmium sulfate 0Á2 mol/l, sodium and ammonium sulfate. One can either recycle it as a chemical bath, or recover the cadmium content by electrowinning; in this case the residual concentration of hydrogen peroxide is electrochemically reduced at the beginning of cadmium electrolysis. The raffinate solution is recycled into the stripping reactor. The pure cadmium metal recovered may be dissolved in a dilute sulfuric acid solution by means of internal electrolysis with two electrodes: a platinized platinum grid as cathode and the cadmium metal as anode. According to the mass of cadmium dissolved it is possible to obtain a concentrated solution of pure cadmium sulfate. The global process recovers at least 99Á999% of cadmium and generates only solid sulfur and a liquid effluent containing traces of cadmium ( < 10 lg/l).

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Section: Electrowinning Of Cadmiummentioning

confidence: 99%

Cadmium recovery and recycling from chemical bath deposition of CdS thin layers

Malinowska

Rakib

Durand

2002

Progress in Photovoltaics

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“…26 Lawrence Livermore National Laboratory researchers also studied the use of ME0 to treat DOE LLMW combustibles, such as Trimsol oil, cellulosic materials, rubber, latex, and plastics in laboratory-and pilot-scale r e a c t o r~.~~-~~ The German Institute for Chemical Technology conducted relevant kinetic studies of ME0.30,31 LANL used cobalt and silver to treat various mixed wastes, including isopropanol, cellulose, and cheesecloth rags. 32 The French Atomic Energy Commissariat conducted mechanistic studies of the destruction of dodecane using ~i1ver.j~ PNNL conducted laboratory-scale tests to apply CEO to the destruction of torpedo fuel wastes, specifically, the U.S. Navy's Otto Fuel II. 34 Electrochemical oxidation processes have also been applied to the destruction of chemical warfare agents.…”

Section: Mediatedkatalyzed Electrochemical Oxidation (Meo/ceo)mentioning

confidence: 99%

Electrochemical treatment and minimization of defense‐related wastes

Pillay

Billingsley²,

Balkey

2000

Federal Facilities Envir J

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The U.S. Departments of Energy (DOE) and Defense (DOD) generate hazardous wastes as a result of routine operations. Waste types range from solvents, fuels, lubricants, and sludges to streams containing mixtures of these and other inorganic and organic compounds, along with potentially radioactive materials. Many of these compounds are amenable to treatment by electrochemical processes that destroy hazardous organic contaminants in aqueous streams at ambient temperatures and pressure. It is also possible to separate the radioactive components of these wastes from solution using electrochemical processes. In this article, we discuss the environmental factors and issues associated with electrochemical waste treatment processes. We summarize the federal regulations that compel government agencies to conduct environmental management activities. Applications of electrochemical processes to waste treatment and waste minimization at DOE and DOD sites are presented, and issues associated with acceptance of these processes are addressed.

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“…In recent years, there has been considerable interest in the development of effective electrochemical procedures for the destruction of toxic and biorefractory organic pollutants for wastewater treatment. Anodic oxidation [1][2][3][4][5] and indirect electro-oxidation, either with metallic redox couples [5][6][7] or with electrogeneration of strong oxidants, 2,5,[8][9][10][11][12][13][14][15] are the most common electrolytic techniques for this applicability. Recently, we proposed 16 a novel electrochemical method for the purification of acidic wastewater based on the use of an Fe/O 2 cell.…”

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confidence: 99%

Use of an Acidic Fe / O 2 Cell for Wastewater Treatment: Degradation of Aniline

Brillas

Sauleda

Casado³

1999

J. Electrochem. Soc.

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Solutions containing 0.50 mol dm Ϫ3 Na 2 SO 4 and aniline concentrations between 129 and 1000 ppm have been decontaminated using an acidic Fe/O 2 cell with an Fe anode and a carbon-poly(tetrafluoroethylene) O 2 -fed cathode. This system produces spontaneously strong oxidizing radicals, such as OH • and HO 2• , which react with pollutants. Decontamination is more efficient for solutions with pH > 3 where intermediates coagulate with the Fe(OH) 3 precipitate formed. A 95% degradation is reached after 1 h of treatment of 129 ppm of aniline at initial pH 4 and at 35ЊC. For higher substrate levels, pollutants are quickly destroyed if the pH is regulated between 4 and 5. After 2 h, solutions up to 500 ppm of aniline are almost completely degraded, whereas 81% of the degradation is reached for 1000 ppm of substrate. Benzoquinone and nitrobenzene are detected as intermediates. An insignificant accumulation of these products is found in the treatment of 1000 ppm of substrate, suggesting the formation of polymers that coagulate with the Fe(OH) 3 precipitate. Low concentrations of ammonium and nitrate ions have been determined in treated solutions. The major part of the initial carbon and nitrogen is retained in the precipitate, indicating that coagulation of intermediates predominates over their mineralization. A reaction pathway for the degradation of aniline involving all intermediates detected is proposed.

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Electrochemical Treatment of Mixed and Hazardous Waste

Cited by 3 publications

References 4 publications

Cadmium recovery and recycling from chemical bath deposition of CdS thin layers

Cadmium recovery and recycling from chemical bath deposition of CdS thin layers

Electrochemical treatment and minimization of defense‐related wastes

Use of an Acidic Fe / O 2 Cell for Wastewater Treatment: Degradation of Aniline

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