Olefin Sulfonate (AOS) Storage & Tank Compatibility

Storing Olefin Sulfonate (AOS)? Start Here

Olefin sulfonate — most often supplied as sodium C14-16 alpha-olefin sulfonate (AOS) — is a workhorse anionic surfactant produced by sulfonating linear alpha-olefins. It is sold as a water-based solution (commonly 40-45% active, the "AOS-40" grade) or as a powder/flake. The blend is a mixture of alkene-sulfonate and hydroxyalkane-sulfonate isomers in a water carrier, with small amounts of sodium sulfate and sodium chloride by-salts. AOS is prized for high foam, good detergency, hard-water tolerance and stability across a broad pH range, which is why it shows up in shampoos, body washes, hand soaps, hard-surface and industrial cleaners, and as a foaming agent in enhanced oil recovery. Because it is an aqueous, near-neutral-to-mildly-alkaline surfactant rather than a solvent, fuel or strong oxidizer, materials of construction (MOC) selection is straightforward — but the right tank still matters for irritant handling, foam control and long-term storage life.

Is Olefin Sulfonate Compatible with Polyethylene (HDPE / XLPE) Tanks?

Yes — polyethylene is a sound choice. Olefin sulfonate solutions are aqueous anionic surfactant blends, and polyethylene is broadly unaffected by aqueous solutions of salts and mild alkalis. Both HDPE and crosslinked polyethylene (XLPE) handle dilute and concentrated surfactant solutions well, with no swelling or solvent attack of the kind that fuels, naphtha or aromatic solvents would cause. This makes standard poly tanks a practical, economical option for storing AOS concentrates and working dilutions. Two cautions: confirm the supplied product's pH and preservative against the specific SDS, and select gaskets, valves and fittings (EPDM is a reliable default) for the same aqueous chemistry rather than assuming the tank rating covers them. For elevated-temperature or high-purity service, 316 stainless is an alternative.

Material compatibility at a glance

Olefin sulfonate is supplied as a water-based anionic surfactant solution, so the dominant compatibility driver is an aqueous, near-neutral-to-mildly-alkaline medium rather than any aggressive solvent or oxidizer. Polyethylene (HDPE and XLPE), polypropylene, FRP and 316 stainless all handle it well. Carbon steel should be lined to avoid aqueous corrosion. Match gaskets and seals (EPDM is a strong default) to the same chemistry.

Ratings: S suitable · C conditional / limited · U unsuitable. Verify against the cited resistance charts and your concentration/temperature before specifying.

The safety that actually matters

• Causes serious eye damage (H318) — wear chemical splash goggles or a face shield when handling concentrate.
• Causes skin irritation (H315) — use chemical-resistant gloves and avoid repeated or prolonged skin contact.
• Concentrated solutions foam aggressively; fill slowly and provide adequate tank vapor/foam space to avoid overflow.
• May be slippery if spilled; clean up promptly to prevent slip hazards.
• Keep out of storm drains and surface water; though biodegradable, surfactants can harm aquatic life at concentration.
• Always consult the specific supplier Safety Data Sheet — signal word, pictograms and ratings vary with active content and preservative.

Common questions

Can I store olefin sulfonate (AOS) in an HDPE or XLPE poly tank?

Yes. AOS is an aqueous anionic surfactant solution, and polyethylene resists aqueous salt and mild-alkali solutions well. Standard HDPE and XLPE tanks are a common, economical choice for surfactant storage. Match the gaskets, valves and fittings to the same chemistry and confirm pH against your supplier SDS.

Does olefin sulfonate require a special high-specific-gravity tank?

Generally no. As-supplied AOS solutions are only slightly denser than water (about 1.05-1.10 g/cm³), so a standard 1.5+ specific-gravity-rated poly tank is normally sufficient. Confirm the actual product density on your SDS before sizing.

Is olefin sulfonate flammable?

No. The water-based surfactant solution is non-flammable and has no flash point. The primary hazards are eye damage and skin irritation from the concentrate, not fire.

What gasket and seal materials work with olefin sulfonate?

EPDM is a strong default for this aqueous, near-neutral-to-mildly-alkaline surfactant. PTFE-faced gaskets are also reliable. Always verify elastomer selection against the specific formulation, especially if preservatives or co-solvents are present.