The science of sorbents and how they actually work ?

Polypropylene Sorbents What are they & how are they made ?

  • Better known as ‘meltblown’ - polypropylene fibres which are produced by blowing of very fine squirts of polypropylene at a high speed and temperature (oil based product)
  • Meltblown fine fibres are collected continuosly and are laid down to form a mat – this fibre generating process imparts a huge charge on the surface of the fibres which makes them repellent of water (hydrophobic)
  • The mat resists water but forms bonds with any other liquids that share the same molecular structure – like oil & other hydrocarbons, making them ideal for oil based liquid clean up.
  • The mat has no attraction to water based liquids, opposing them in a similar way that the same poles of a magnet repel.
  • The poly-based fibres must be treated with a surfactant to make them effective with aqueous based liquids such as solvents and other non-hydrocarbon based liquids

Polypropylene Adsorption How does it work ?

  • Meltblown is plastic – the fibres don’t absorb anything, rather they get coated with the oil based liquid. This is called ADSORPTION. The liquid is quite simply added to the surface of the fibres.
  • Meltblown products can absorb up to 15 times it’s own weight when soaking up petroleum based liquids. To achieve this high number, the fibres must have a large amount of air space (loft) between them to retain as much fluid as possible.
  • A higher loft mat can absorb more product quickly but will be structurally weaker than a dense laminated product – it is important therefore to select the right combination of size, weight and construction to optimize your performance. Enviroguard can work with you to develop optimal solution.

Cellulose Sorbents Natural fibre based products

  • Cellulose fibres have an additional attribute that meltblown does not have – they can also absorb liquids as they take into their very structure the liquid presented to them
  • Cellulose fibres also adsorb so they can handle both oil & acqueous or slippery liquids – making them excellent ‘universal’ sorbents (they need to be adapted to repell water if used for oil based liquids)
  • On average, cellulose sustainable fibre sorbents can absorb up to 12 times their own weight of low viscosity water based liquids and can also absorb (less effectively) oil based liquids because they have more surface area (natural fibres are much finer than synthetic based fibres)

(Comparing Performance) Pros & Cons of Polypropylene Vs. Cellulose

  • Meltblown fibres are most effective for absorbing oil & hydrocarbon based liquids as they repell all aqueous (water) based liquids – hydrophobic
  • This makes meltblown oil only sorbents the superior choice for all outdoor applications – particularly recovery of oil spills on water
  • Cellulose fibre based sorbents are superior to meltblown at absorbing aqueous (water) based liquids as they absorb liquid into their fibres and are less slippery than surfactant treated meltblown fibres – superior choice for indoor universal applications.
  • Cellulose fibres are less effective for oil based spills or outdoor applications as they must be adapted to repell water
  • Meltblown polypropylene fibres are chemically very stable and can adsorb virtually all liquids – making polypropylene based sorbents the only choice for unknown or hazardous (HazMat) materials
  • Meltblown is resistant to high heat and will melt before it burns while cellulose will not melt – although one must be aware that any sorbent can be forced to burn (meltblown or cellulose) because the sorbent will take on the physical or hazourdous attributes of the absorbed liquids

Sorbent Selection Guide

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