Reverse osmosis membrane separation technology is a rapidly developing water treatment technology in recent years. It is widely used in various fields such as seawater desalination, electric power, petrochemical, electronics, medicine, municipal environmental protection, etc. The biggest problem encountered in the application of reverse osmosis technology is membrane fouling. The pollution of reverse osmosis membrane not only reduces the economical operation of the system, but also becomes the key to influence the further promotion of reverse osmosis technology. So what about the reverse osmosis membrane pollution process?

It is well known that the roll-type reverse osmosis is based on pressure as the main driving force, and operates in a cross-flow mode to achieve separation of solvent and solute under high pressure. Since the reverse osmosis membrane itself is very dense, the pore size of the membrane is below 1 nm. With the extension of the running time, various contaminants can easily block the pores of the membrane, forming a contaminated layer on the membrane surface, affecting the flux and the salt rejection rate. Therefore, it is necessary to periodically clean the membrane to restore performance, but the unrecoverable loss is difficult to avoid, which results in an increase in operating costs. In order to reduce membrane fouling, the current measures include membrane surface modification, optimization of component structure, strengthening of pretreatment and maintenance, etc., but pollution cannot be avoided.

RO reverse osmosis membrane pollution mainly includes adsorption of organic colloidal particles, inorganic scaling and microbial growth. Due to the shape, structure, charge and other characteristics of the pollutants, they have different effects on the membrane properties. Understanding the effects of various types of pollutants on the performance of membrane components is important for preventing, judging and cleaning membrane fouling. The meaning. In this experiment, self-dispensing water was used as raw water to simulate the process of inorganic calcium carbonate pollution and organic colloidal pollution of actual on-site reverse osmosis membrane components. The correlation of reverse osmosis membrane pollution and membrane performance was observed and the membrane fouling mechanism was discussed. Membrane element cleaning can indirectly reflect the contamination of the membrane surface. The pollution of reverse osmosis membrane is generally divided into reversible pollution and irreversible pollution. The structure of the reversible pollution layer is loose, and the adsorption on the membrane surface is not tight. It can be removed under the condition of hydraulic washing. The irreversible pollution is generally close to the membrane surface, and the hydraulic washing cannot be removed. It is only removed by chemical reaction.