PolyDADMAC Powder (CAS 26590-05-6) | Water Treatment Coagulant

Introduction to PolyDADMAC Powder

PolyDADMAC Powder is a white to off-white, water-soluble cationic polyelectrolyte made from diallyldimethylammonium chloride repeat units, giving a linear chain with permanent quaternary ammonium charge. It neutralizes negatively charged clay, organic colloids and biomass, so it is used mainly in municipal and industrial water treatment and pulp-and-paper process water. The dry powder suits plants that need compact storage and frequent on-site make-down.

Compared with ferric chloride, PolyDADMAC usually needs only 0.2–2 mg/L active polymer versus typical 10–100 mg/L metal salt at similar turbidity removal, leaving less inorganic sludge. The practical risk is hygroscopic caking and overdosing: open bags absorb moisture, form lumps, dissolve slowly, and excess cationic polymer can restabilize fine particles during jar tests unless sealed storage and 0.1–0.5% dilute dosing are used.

Key Features of PolyDADMAC

• Permanent quaternary charge: The diallyldimethylammonium repeat unit keeps positive charge across acidic to alkaline pH, so dosing does not rely on pH adjustment.
• High charge density: Cationic sites neutralize negative clay and organic colloids at 0.1–5 mg/L, reducing turbidity before floc bridging starts.
• Low metal sludge: The polymer does not add iron or aluminum hydroxide mass, lowering sludge volume when replacing part of a metal coagulant.
• High-solid powder dosing: 96–99% solid content reduces storage volume, but make-down must stay at 0.1–0.5% to avoid gel lumps.
• Linear floc bridging: The dissolved chain connects microflocs into larger, shear-resistant aggregates for settlers, DAF units and filters.

PolyDADMAC Powder Chemical & Physical Properties

Applications of PolyDADMAC Powder

Municipal and industrial clarification/DAF: Quaternary ammonium sites neutralize negatively charged clay and organic colloids, forming microflocs. Typical dose is 0.1–5 mg/L (0.1–5 ppm) active polymer, adjusted by jar test and cationic demand.

Sludge dewatering: Cationic chains bind biosolids and release bound water, improving belt press, centrifuge or filter press capture. Typical dose is 1–5 kg/t DS (2–10 lb/ton DS).

Paper retention and drainage: PolyDADMAC neutralizes anionic trash, retains fillers and fines, and improves white-water closure. Typical dose is 50–300 g/t (0.11–0.66 lb/ton) active polymer.

Textile dye effluent: Positive sites complex anionic dye groups and suspended fibers, helping color and solids removal. Typical dose is 5–30 mg/L (5–30 ppm), depending on color and COD load.

Storage & Safety Precautions for PolyDADMAC Powder

Storage: Keep bags sealed on dry pallets at 5–35 °C (41–95 °F). PolyDADMAC Powder is hygroscopic; moisture turns free-flowing powder into lumps and slows dissolution. Store away from strong oxidizers and concentrated anionic polymers; contact can form rubbery insoluble complexes. Do not place torn bags on damp concrete because wet powder creates a slippery film.

Safety: Typical GHS handling classification for polymer dust is Eye Irrit. 2; confirm destination-country SDS. Wear goggles, nitrile gloves and a P2/N95 respirator when handling open bags. For spills, suppress dust, collect into a labeled drum, then wash residue with water; warn crews about wet, slippery surfaces.

Transport: Non-DG for dry powder in sealed packaging. Verify local polymer or water-treatment chemical rules before export.

QC practice: Before loading, check solid content by oven drying per ISO 3251, then prepare a 0.5% solution to check fish-eyes and pH 4.0–7.0 per ISO 10523. Slow dissolution usually points to moisture uptake during storage.

PolyDADMAC Powder FAQ

Q: Is CAS 26590-05-6 PolyDADMAC Powder effective for high-color low-turbidity water?

A: Yes, if color comes from anionic organics. Its quaternary charge neutralizes humic-type colloids. Start jar tests at 0.2–1 mg/L and check cationic demand before increasing dose.

Q: Why does PolyDADMAC Powder form lumps when made down?

A: It hydrates fast on the surface. If powder is dumped into water without agitation, outer gel blocks wetting. Add slowly to a vortex and target a 0.1–0.5% solution.

Q: Can PolyDADMAC Powder replace PAC directly?

A: Not always. It removes charge and builds floc, but high turbidity may need PAC weight. Use jar tests; typical polymer dose is 0.1–2 mg/L, PAC 10–50 mg/L.