Economic Diffusion Dialysis (DD) Cation-Exchange Membrane (CEM) for Waste Alkali Recovery, CWAREDDCEM
Use your own shipping account?
We support FedEx, UPS, and DHL third-party billing for institutional customers.
Place your order first, then email shipping@echemsupplies.com with your account details and order number. We'll generate the label using your account and refund your shipping charges, less a handling fee.
Add-Ons
Diffusion dialysis (DD) (or related Donnan-driven dialysis processes) utilizing specialized cation-exchange membranes (CEMs) is an eco-friendly, energy-saving membrane separation technology designed to recover free alkalis (such as sodium hydroxide, NaOH, or potassium hydroxide, KOH) from industrial wastewater and process streams. Like acid recovery diffusion dialysis, it operates entirely on a concentration gradient without requiring an external direct-current (DC) power source.
To withstand and perform effectively in alkaline environments, diffusion dialysis and Donnan dialysis CEMs require specific physicochemical traits: (1) High Alkali Permeability: Maximizes the flux of alkali constituents across the membrane, ensuring high processing capacity and a compact physical stack footprint. (2) Strong Alkali and Chemical Resistance: Because feed and recovered solutions involve concentrated caustics (NaOH or KOH), the polymer matrix (often reinforced fluoropolymers or specialized stable hydrocarbon backbones) must resist chemical degradation, softening, or structural breakdown over long-term operation. (3) High Permselectivity: Effectively blocks the migration of unwanted anions and multivalent ions (such as dissolved silicates, aluminates, or heavy metals) to ensure high purity in the recovered alkali product. (4) Low Swelling Ratio: Minimizes dimensional changes and warping when subjected to sharp ionic strength shifts between concentrated waste streams and dilute receiving water.
| Part Number |
CWAREDDCEM (C-WAR-EDDCEM) |
| Working Mechanism |
The whole diffusion dialysis is consisted of a series of dialysis and diffusion chambers that was separated by a cation exchange membrane. The waste alkali solution and receiving solution (eg: tap water) was fed into chambers and the cations (also bring hydroxide ions) from the waste acid will go through the membrane and enter into the tap water to complete the alkali recovery. |
| Membrane Thickness (Dry) |
~0.12 um |
| Dialysis Constant |
>1*10^-7 m/s |
| OH-/ALO2+ Separation Factor |
>10 |
| Water Content |
>30% |
| Operation Temperature |
≤50°C |
| Penetration Strength |
> 5 N |
| Package Grade |
L10-40cm*W10-40cm/pcs/pack |
Reference:
- X. Wang, et al., Ultrathin porous cation exchange membranes for high-performance diffusion dialysis alkali recovery, AIChE J., 2026, 72, e70152
- J. Hao, et al., A simple and green preparation of PVA-based cation exchange hybrid membranes for alkali recovery, Journal of Membrane Science, 2013, 433, 10-16