What does 'flux decline' refer to in membrane performance?

Flux decline refers to a decrease in the rate at which water passes through a membrane over time. In membrane performance, this decline is often attributed to various factors, with compaction being a significant one. As pressure and flow through the membrane increase, the membrane material can become denser or compacted, which reduces the effective pore size and increases resistance to flow. This leads to a drop in the overall water flux.

Other factors can also contribute to flux decline, such as fouling, where particles or microorganisms accumulate on the membrane surface, and scaling, where minerals precipitate and block the pores. However, the emphasis on compaction is important because it highlights a physical change in the membrane that impacts performance, reinforcing the connection between structural integrity and operational efficiency.

Understanding flux decline is crucial for operators, as it helps in diagnosing issues with membrane systems and implementing appropriate maintenance or operational changes to uphold performance.