Separation Mechanism of Membrane Processes in Major Industrial Pure Water Treatment

microfiltration

Screening

Water, solvent dissolved

Suspended solids, particles, fibers, and bacteria

Symmetric and asymmetric porous membranes

Ultrafiltration

Screening

Water, solvents, ions, and small molecules (relative molecular mass <1000)

Biochemical products, colloids and macromolecules (relative molecular mass 1000-300000)

Porous membrane with skin

nanofiltration

Sieving + Dissolution/Diffusion

Water and solvents (relative molecular mass <200)

Solutes, divalent salts, sugars, and dyes (relative molecular mass 200-1000)

Dense asymmetric membranes and composite membranes

reverse osmosis

Dissolution/Diffusion

Water and solvents

All suspended matter, solute and salt

Dense asymmetric membranes and composite membranes

People's Permeation Analysis

Ion exchange

Electrolytic ions

Non-dissociated and macromolecular substances

Ion exchange membrane

Dialysis

diffusion

Ions, low molecular weight organic matter, acids and bases

Soluble and suspended matter with a relative molecular mass greater than 1000

Asymmetric membranes and ion exchange membranes

Pervaporation

Dissolution/Diffusion

Solute or solvent (vapor of the easily permeable component)

Solute or solvent (liquid of a component that is difficult to penetrate)

Composite membranes and homogeneous membranes

Membrane distillation

Vapor-liquid balance

Solute or solvent (easily vaporized and permeable components)

Solute and solvent (components that are difficult to permeate and vaporize)

porous membrane

Gas separation

Dissolution/Diffusion

Permeable gases and vapors

Impermeable gases and vapors

Composite membranes and homogeneous membranes

liquid film

Reaction promotion and diffusion

Electrolyte ions

Non-electrolyte ions

carrier membrane

Membrane contactor

Allocation coefficient

Substances that are easily diffused and penetrated

Substances that are difficult to diffuse and penetrate

Porous membranes and non-porous membranes