¿Por qué disminuye el flujo del permeado después de limpiar las membranas de RO?? Ideas críticas que debes saber

Reverse osmosis RO membranes are pivotal in water purification processes. Regular cleaning is essential to maintain their efficiency. Sin embargo, it’s perplexing when, after a thorough cleaning, the permeate flow doesn’t improve but instead declines. This article delves into the reasons behind this counterintuitive outcome and offers actionable solutions.​

Understanding the Cleaning Sequence Of RO Membranes

The cleaning sequence of the RO membranes are critical. An incorrect order can exacerbate fouling rather than alleviate it.

• Organic and Biofouling: Initiate with an alkaline cleaning to remove organic matter and biofilms. Alkaline solutions, such as sodium hydroxide (Naóbra), effectively break down organic compounds.

• Inorganic Scaling: Follow with an acid cleaning to dissolve inorganic scales like calcium carbonate. Acidic solutions, such as hydrochloric acid (HCl), are effective in this regard.

Reversing this sequence can lead to the compaction of organic foulants, making them more challenging to remove. ​

The Role of Cleaning Agents and Conditions

The choice of cleaning agents and their application conditions significantly impact cleaning efficacy.​

• Concentration and pH: Cleaning solutions typically range from 0.03–2.0% in concentration. The pH should be adjusted according to the type of fouling. ​

• Temperatura: Elevated temperatures can enhance cleaning efficiency but must remain within the membrane’s tolerance limits.​

• Contact Time: Adequate soaking time ensures thorough cleaning. Sin embargo, prolonged exposure can lead to membrane degradation.​

Potential Causes for Decreased Permeate Flow Post-Cleaning

1. Incomplete Removal of Foulants: Residual foulants can continue to impede water flow.​

2. Membrane Damage: Aggressive cleaning agents or improper pH levels can damage the membrane’s surface, reducing its permeability.​

3. Re-deposition of Foulants: If the cleaning solution becomes saturated, foulants can re-deposit onto the membrane.

4. Biofilm Regrowth: Inadequate removal of biofilms can lead to rapid regrowth, diminishing permeate flow.​

Recommended Cleaning Protocol Of RO Membranes

A structured cleaning protocol can mitigate the risks associated with membrane cleaning.​

1. Alkaline Cleaning: Use a 0.1% NaOH solution at pH 12 and 35°C to remove organic and biological foulants.

2. Acid Cleaning: Follow with a 0.1% HCl solution at pH 2 and 25°C to dissolve inorganic scales.​

3. Rinse: Thoroughly rinse the system with deionized water between cleaning steps to prevent chemical reactions.​

4. Biocide Treatment: If biofouling is severe, incorporate a biocide treatment to eliminate microbial contaminants.​

Data Supporting Cleaning Efficacy

The following table illustrates the impact of proper cleaning sequences on permeate flow recovery:​

​Data Source: Membrane Cleaning Studies, 2023​

Conclusión

Proper cleaning of RO membranes is a delicate balance of chemistry and procedure. Understanding the nature of fouling and applying the correct cleaning sequence with appropriate agents and conditions is crucial. Neglecting these factors can lead to decreased performance and increased operational costs