Acid- and Alkali-resistant NF for Process Liquor Recovery

Recover usable process liquor

Acidic and alkaline process liquors can contain recoverable chemicals alongside organic matter, metals, oils or colour bodies. Acid- and alkali-resistant nanofiltration may separate selected impurities while returning a suitable stream to production. The intended recovered stream and its reuse specification must be defined first.

Match the membrane to the duty

AS is a candidate for acid purification, metal-ion concentration and acidic mother-liquor recovery. BS is a candidate for caustic recovery and treatment of alkaline cleaning or process solutions. For example, retaining proteins, oils or colour bodies from a cleaning stream may support recovery of a reusable alkaline permeate.

Acid or base concentration, salts, oxidants and temperature all affect feasibility. Pretreatment and compatible pumps, seals and piping are part of the process design. pH alone does not demonstrate chemical compatibility.

Demonstrate reuse quality over repeated cycles

Bench tests should measure impurity passage, chemical recovery, sustained flux and cleaning behaviour at realistic concentrations. Recovered liquor must satisfy the receiving process, including the effect of impurities that accumulate during repeated reuse. Compare the full route using chemical demand, energy, waste treatment and product quality before deciding how membrane recovery fits with existing treatment.