A water filter works by creating physical barriers that water must pass through, trapping impurities and leaving cleaner water behind. This process is often achieved using membranes, sieves, or ion exchange.
The Filtration Process Explained
The core principle is simple: water is forced through a material designed to block contaminants. Different types of filters use different methods to achieve this:
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Membrane Filtration: A thin membrane acts as a sieve, allowing water molecules to pass but blocking larger particles like sediment, bacteria, and some dissolved solids. This is common in reverse osmosis (RO) systems and ultrafiltration (UF) systems. Reference: At the most basic level, most water filtration works by setting up physical barriers for water to pass through.
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Sieve Filtration: This uses a porous material, like sand or activated carbon, to trap impurities. Larger particles are caught in the spaces between the material's grains. This is often a first step in many multi-stage filtration systems. Reference: As the water passes through these barriers (often a membrane, sieve, or sometimes an ion exchange process), sediment and impurities are captured, leaving only clean, filtered water.
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Ion Exchange: This method doesn't use a physical barrier in the same way. Instead, it uses resin beads that attract and bind to specific ions, like calcium and magnesium (which cause hardness), removing them from the water.
Types of Water Filters and Their Applications
Different filter types are suited for different needs:
- Sediment Filters: Remove sand, silt, and rust.
- Carbon Filters: Absorb chlorine, organic compounds, and improve taste and odor.
- Reverse Osmosis (RO) Filters: Remove a wide range of contaminants, including dissolved solids, salts, and heavy metals. They are often used for drinking water purification.
- Ultraviolet (UV) Filters: Kill bacteria and viruses using ultraviolet light.
Example: A typical home water filter pitcher might combine a sediment filter with a carbon filter to provide cleaner, better-tasting water.
