Technology overview
The disposal of toxic organics
is often a problem in many industries. Our SILVER
II™ process represents a safe, environmentally
friendly alternative to incineration as a method
for the complete destruction of a variety of complex
organic materials. Destruction of waste material
is carried out by electrochemical oxidation using
a highly reactive form of silver, Ag++ ions. The
process has both safety and environmental benefits
over alternative technologies.
Technology Presentation (PowerPoint)
Silver II
SILVER IITM is a patented process of electrochemical mediated oxidation for providing a safe and cost effective route for the irreversible destruction of toxic or hazardous organic compounds. It was originally developed for organic nuclear waste management. The scope of its application was then expanded to Chemical Weapons, including the stockpile held by the US military under a $23m Assembled Chemical Weapons Assessment (ACWA) programme. In addition applications in toxic or special wastes falling under landfill and IPPC guidelines have been explored.
How does it work?
At the heart of the process is the chemical oxidation of organic molecules by the Ag[II] ion one of the most oxidising species known. Radical species generated by Ag[II] attack the organic substrate progressively converting it in a series of steps irreversibly to CO2, water and residual salts from hetero-atoms (including halides, sulphur, nitrogen and phosphorus).
SILVER II oxidation reaction
During the oxidation step, Ag[II] is reduced back to Ag[I]. This is then regenerated to Ag[II] again at the electrochemical anode.
Applications of Silver II have included:
Nuclear
- Tributyl Phosphate
- Odourless Kerosene and other extractants/solvents
- Cellulose swabs, tissues
- Contaminated oils
- Ion exchange resins
- Decontamination (metals and plastics)
Fine chemicals and pharmaceuticals
- Highly toxic chemicals, neurotoxins
- Toxic materials adsorbed on solids (vermiculite, silica, carbon)
- Pesticides, herbicides
- Carbon 14 ISOTOPE reclamation
Military
- ACWA
- Nerve agents (VX, GB, etc.)
- Blister agents (Mustard, etc.)
- Explosives and propellants
Target compounds have also included:
- Dodecane Chlorofluorobenzoic acid
- Octanoic acid
- Tributyl phosphate m-nitro p-toluidine
- Butanol
- Kerosene Toluene
- Petroleum spirits
- Dioxan Dinitrophenol
- Isopropanol
- Ether Nitrosobenzene
- Tetrahydrofuran
- Cyclohexane Urea-formaldehyde
- Methylene Chloride
- 2-methoxyethanol
- Triethanolamine
- Aliphatic amines
- Phenol
- Methanol
- Dimethyl formamide
- Xylene
- Chloroform
- Trichlorobenzene
- 2 chloroethylethyl sulphide
- Ethanol
- p-toluenesulphonic acid
- Chlorobenzene
Environmental
The destruction efficiency of SILVER II™ has been demonstrated at >99.9999%. Reagent consumption in the system are minimised as they are continually recycled. The off-gas volumes produced are low allowing a situation where they can be held on production and tested before release to the atmosphere. SILVER II™ is a low temperature process, so no dioxins, PCBs or PAHs are formed (cf. incineration). The chemistry involved within the system separates out impurities present in the feed to a small volume of waste, while recycling the bulk of the chemicals and the plant is self-cleaning.
Safety
It is a low temperature process (typically 80ºC) operating at atmospheric pressure. The reaction rate of the process is directly controllable by changing the current being applied and shut-down is simple and safe – simply turn off the power supply. The plant is easy to operate with no lost time accidents during the 3,500 hours of operation during the ACWA programme in the US. The system is made up of a range of standard industrial electrochemical cells which are well understood and proven.
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