This technology, known as membranes, has been recognized as a reputable purification technology throughout its history and has made a name for itself with many advantages.
Among the advantages of membrane technology, it can be listed that it does not involve any chemical additives, provides lower energy consumption compared to others, and works with an easy and well-regulated process transmission.
In short, a membrane can be described as a thin layer with very small holes or pores, made of synthetic plastic material. However, it should be noted that there may be differences in pore sizes when considering different types of water treatment membranes. Types of membranes used for water purification can be diversified as microfiltration membranes (MF), ultrafiltration membranes (UF), nanofiltration membranes (NF), and reverse osmosis (RO) membranes.
In principle, membranes can be said to have a very simple system. Membranes are essentially a system that serves the purpose of filtering solid substances or other materials by allowing water to flow through and acting as a very specialized filter. Membrane filtration can be used as an alternative for many processes, from flocculation and sedimentation techniques to adsorption (sand filters and activated carbon filters, ion exchangers), extraction, and even distillation.
What Are the Types of Membranes?
Membranes come in various module types. Membranes are commonly produced and used in four different forms: flat plate, hollow fiber, tubular, and multi-hole.
Flat Plate Membranes
Flat plate membranes, which are in the form of sheets, have a layer that performs active separation on one side while allowing purified water to be obtained by filtering water through the membrane on the other side. Flat plate membranes are often produced by coating a polymer onto a support material. In this way, the mechanical strength of the membrane is provided by the non-woven fabric, and the separation property is achieved with the polymer layer.
Hollow Fiber Membranes
Hollow fiber membranes are in the form of cylinders and can operate in two ways. These can be defined as membrane types that can work from the inside out and the outside in. In other words, the layer where the basic separation process takes place can be produced on the inside or outside surface of the membrane.
In processes where the concentration of suspended solids is higher than required, membranes with the active layer on the outside can be preferred. Additionally, these membranes can be produced by coating a polymer on a hollow mesh fiber to increase their mechanical strength. These types of membranes are referred to as reinforced hollow fiber membranes.
Tubular Membranes
Tubular membranes, which are cylindrical and have slightly wider diameters, should be preferred, especially in waters with high suspended solid content. Tubular membranes are produced by coating the inner surfaces of non-woven cylindrical fabric with a polymer. These membranes, with the active layer on the inner surface, operate on the inside-out principle.
Membranes Referred to as Multi-Hole
Membranes referred to as multi-hole membranes, which have multiple water flow channels in their structure, operate on the inside-out principle. These membranes can be made of polymer or ceramic. However, ceramic membranes are often seen to be produced in this type.
