Dr Ashley J. Wilson Technical Director Carafiltration Ltd.
CARASOLS – Developed for a Cleaner, Greener Environment WHAT ARE CARASOLS? CARASOLS are a range of natural, innovative, harmless – but potent – bio-adsorbents for the removal of contaminants from both aqueous and gaseous industrial and agricultural effluent.
Carasols are:- · Derived from specific waste materials fromfood processing which currently attract a cost for disposal · Low-cost (capital and recurrent) compared with alternatives ·In the form of a range of non-hazardous, safe/pleasant-to-use powdered media ·Extremely versatile with respect to the wide range of molecules and ions they will trap ·Able to be used when wet or dry for waste-water or gas/odour applications ·Very strong binding of the contaminant to Carasol Difficult to de-sorb what is trapped ·Completely biodegradable in landfill and safe to incinerate.
CARASOLS are the result of:- ·Six years R & D at the University of York ·Ten European and DTI - sponsored* investigations into: ·How best to ‘contact’ the bioadsorbent with the contaminant i.e. in a packed or fluidised bed scrubber ·How the adsorbents work (physical and biochemical trapping mechanisms) ·What contaminants they will trap (i.e. range of molecules and ions) ·How to source the raw material and prepare it as an adsorbent ·How to add value to the raw materials by the addition of functionalised groups and biocides etc. ·How to detect when the bioadsorbent is saturated with contaminant ·How best to dispose of the bioadsorbent/contaminant. * SMART (X2), EU LIFE-Environmental, Bio-Wise, RECRAFT, KTP, TIDE etc.
RAW MATERIAL • Carasols are manufactured from a food waste (so they are obviously derived from natural materials) which currently attracts a cost for disposal. The food waste is the carapace or shell of a range of marine crustacea such as: • · Crab • · Prawn • · Lobster • · Langoustine • The Seafish Industries Authority is currently very concerned about the volume of shellfish waste illegally dumped at sea and also the major odour problems arising from putrefying shellfish waste dumped in landfill. It was important to find a use for this waste.
HOW ARE CARASOLS MADE? ·Dirty carapace is sourced and cleaned with mild caustic to remove residual soft tissue. · Rinsed and dried to <5% water content. · Fragmented into 10 mm pieces. · Rinsed with a biocide solution (Amolden or Cetrimide) to extend the shelf-life and increase binding efficiency. · Treated with a ‘mordant’ or functionalised group to increase binding capacity or improve specificity. · Gently milled to a powder using a pin-mill or high shear to retain structure. · Screened (sieved) to a particle size between 250 mm and 720 mm. (Mean 480 mm) · Bagged as Carasol 480 (waste-water cleaning) or Carasol 120 (gas and odour scrubbing).
HOW DO CARASOLS BIND/TRAP? I Physisorption ·Micro-pores similar to those in activated carbon provide a large surface-area-to-volume ratio. ·1g of Carasol 480 typically has a surface area of approx. 15 m2.
HOW DO THEY BIND/TRAP? • Synergistically with: • II Chemisorption • (amines, hydroxyl, carboxyl groups, ion-exchange and neutralisation) • Chitin and the chitosan family of molecules • + • Fibrous proteins • + • Calcium carbonate
WHAT WILL THEY TRAP? Original Application Carasols were initially developed for removal of Textile Dyehouse Effluent Herbert Roberts Ltd. – Worsted dyer in Keighley, West Yorkshire. Problems with a variety of dyestuffs and metal ions in their effluent stream. · Dyestuffs · Metal ions (cobalt, chromium etc.) · Textile ‘finishes’ (insecticides, flame-retardants, anti-dust mite finishes).
WHAT WILL THEY TRAP? Versatility Carasols are extremely versatile in their application and will trap a very wide range of contaminating molecules from both wastewater and air. This is because they provide trapping by both physisorption and chemisorption. Typical contaminants they will bind include: · Metal ions (both anionic, cationic and chelated) · Pesticide residues (herbicides and insecticides) · Biocides · Dyes and pigments (printing and graphics) · Phenols and polyphenolics (e.g. humic acid) · Oils from stable oil-in-water and water-in-oil emulsion (e.g. metal cutting fluids) · Antibiotics · Detergents / surfactants · Acid gases inc. oxides of sulphur · Odours inc. mercaptans, various organic sulphides · Dioxins and furans · PCB’s Others, as yet undiscovered!
INDUSTRIAL APPLICATIONS Carasols have application to the cleanup of a broad range of industrial and agricultural processes including: ·Textile dyeing and finishing · Metal plating and finishing (Ni, Cr) · Galvanizing industry (Zn/Pb gas emissions and run-off) · Printed circuit board manufacture (Cu) · Photographic processing (Ag) · Printing press fount solution cleaning · Metal cutting and turning (oil) · Tanning industry (Cr) · Screen printing · Printing ink pigment manufacture · Composting (Odour) · Antibiotic manufacture · Food processing
Carafiltration Ltd. In order to commercialise the product there was a need to establish a Limited company. The Company facilitated: · Licensing of patents (X4) on the technology · Eligibility to apply as an SME for EU & Government research funding · Setting up trading agreements with intermediary companies selling into specialist niches
CONCLUSIONS • Carasols are: • a good example of valuable, novel product, which can be derived from FOOD WASTE • a low cost bio-adsorbent clean-up process • extremely versatile in their breadth of application • leave only a biodegradable residue • safe, clean user-friendly products • a simple to use process