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The Secret of Membranes: Why Are They So Indispensable in Water Treatment?
In today's environmental protection and water resources management, membrane technology has become an indispensable part. This technology covers all scientific processes related to the construction and application of membranes, mainly through semi-permeable membranes to facilitate the transport of substances between or to reject substances. In this process, the pore size of the membrane must be smaller than the diameter of the unwanted substances in order to effectively filter out harmful microorganisms and other substances. Membrane technology is widely used in fields such as water treatment, chemical industry, medicine, biotechnology, food industry, and environmental pollutant removal.
Membrane technology can not only promote the separation of substances, but also effectively improve efficiency in different industrial applications, especially in the use of water resources.
Overview of membrane
One of the advantages of the membrane separation process is that it operates without heating, thus using less energy than traditional thermal separation processes such as distillation or crystallization. This means that membrane technology is capable of many separations that are not possible with heat transfer methods. Taking reverse osmosis as an example, through membrane technology we can provide solutions for the production of drinking water and play a vital role in the sewage treatment process.
In the field of modern environmental protection, membrane technology has received increasing attention, especially in energy recovery technologies, such as fuel cells and osmosis power plants.
Mass transfer model
Mass transfer in membranes can be explained by two basic models: the solution diffusion model and the hydrodynamic model. For many practical applications, these two transport mechanisms often occur simultaneously, especially during ultrafiltration.
Solving the Diffusion Model
In this model, the components to be transported must first be dissolved in the membrane. This model is mainly suitable for closed membranes without natural pores in reverse osmosis and fuel cells. During filtration, a boundary layer forms on the membrane, caused by a concentration gradient created by molecules that cannot pass through the membrane.
Fluid dynamics model
In this model, transport is by convection through the pores. It requires that the size of the hole must be smaller than the diameter of the two separate components. This type of membrane is mainly used in microfiltration and ultrafiltration and is used to separate macromolecules, suspended particles or remove bacteria from solutions.
Types of membrane operation
A variety of membrane operations can be distinguished based on the driving force of the operation, including microfiltration, ultrafiltration, nanofiltration, reverse osmosis, etc. These operations have a wide range of applications in a variety of industries, including food processing, pharmaceutical production, and water treatment.
Membrane shape and flow geometry
There are two main flow configurations in membrane processes: cross-flow and dead-end filtration. Cross-flow filtration is a method in which the liquid flows along the membrane surface, while dead-end filtration is a method in which the liquid flows perpendicular to the membrane surface. Both flow geometries have advantages and disadvantages. Dead-end filtration is typically used for laboratory feasibility studies, while cross-flow filtration is more effective at reducing membrane fouling problems.
Permeability and selectivity
The pore size of a membrane and its selectivity for specific particles are critical to its performance. Membrane manufacturers often differentiate technical membranes by their nominal pore size. Selectivity is related to the type of filtration process, the composition of the membrane, and its electrochemical properties.
The selectivity of membrane technology enables reasonable separation in a variety of environments, such as recovery of industrial gases or water purification processes.
Synthesis and environmental protection of Ba Xiao membrane
The synthesis of biomass membranes is considered a solution to environmental problems. By using natural biological materials, costs can be reduced and secondary pollution avoided. The synthesis process of biofilms involves mixing organic materials with other additives to form the matrix of the membrane. The use of raw materials such as coconut shells and corn stalks enhances the hydrophobicity, pore size and anti-pollution properties of the membrane, allowing it to perform better in water treatment.
To sum up, membrane technology not only plays an important role in industrial water treatment, but also leads the direction of future environmental governance. Today, with the rapid advancement of science and technology, can our water resources be fully used sustainably?
