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What is filtration in separating mixtures? Among the various methods of separation, why is filtration often chosen? Filtration plays a significant role in our daily lives.
This article will discuss when filtration is appropriate, its practical applications, and tips for filtering water at home.
Why Do We Need to Separate Mixtures? What Methods Can Be Used?
In both science and daily life, separating mixtures is often necessary to obtain pure components or extract specific substances for easier handling or analysis. There are six common methods for effective separation:
1
Filtration
Filtration is mainly used to separate solid particles from liquids or gases using a filter medium (e.g., filter paper, mesh, or cloth).
In simple terms, solid particles are trapped by the filter while the liquid or gas passes through.
👉read more: What is the filtration in chemistry definition?
2
Distillation
Distillation involves heating a mixture to a specific liquid’s boiling point, causing it to evaporate into gas. The vapor is then condensed back into liquid form, separating it from the original mixture.
It is commonly used to extract and purify liquids in water treatment, alcohol production, and chemical experiments.
3
Fractional Distillation
This method separates liquid mixtures with components that have similar boiling points.
It relies on the boiling point differences and uses fractional distillation columns to enhance separation efficiency.
This is a key process in refining petroleum.
4
Heating
Heating is a technique that uses thermal energy to induce physical or chemical changes in substances.
When heated to a specific temperature, substances undergo changes such as melting, evaporation, or chemical reactions, which can be used to separate metals from alloys.
5
Extraction
Extraction depends on the difference in solubility of components in two immiscible liquids.
It is used to separate and purify specific components in liquid mixtures, especially when these components have distinct solubility differences in different solvents.
6
Recrystallization
Recrystallization is used to separate pure solid compounds from mixtures based on the differences in solubility at different temperatures, yielding a high-purity product.
When Should Filtration Be Used?
Filtration is ideal when a substance cannot dissolve in a given solvent. It is widely applicable and is particularly useful for heterogeneous mixtures, where solid particles are unevenly distributed in a liquid.
For example, when water contains dirt or sand, the solid particles are trapped by the filter while clean water flows through.
Filtration can also be applied to homogeneous mixtures, especially when removing solid impurities, like in a saltwater solution. Even when the solid particles are fully dissolved, filtration can be used to remove other insoluble substances.
In both everyday life and professional settings, filtration offers a simple and effective solution for separating solid particles.
👉read more:What is Filter Media?
How is Filtration Performed in the Lab? Understanding Gravity and Vacuum Filtration
Filtration in the lab typically involves two methods: gravity filtration and vacuum filtration:
Gravity Filtration
Gravity filtration is suitable for handling large volumes of mixtures or for hot filtration. For hot mixtures, a stemless funnel is recommended to prevent crystal formation from obstructing the filter.
The steps are as follows:
- Secure a funnel over an Erlenmeyer flask and place filter paper inside.
- Fold the filter paper into a cone or groove shape to increase the surface area and speed up filtration.
- Stir the mixture thoroughly before pouring it to avoid solid particles sticking to the container.
- Slowly pour the mixture into the center of the filter paper, avoiding spills.
- The solid particles remain on the filter paper while the filtrate collects in the flask.
- Repeat until the mixture is fully separated.
Vacuum Filtration
Vacuum filtration is ideal for handling small quantities of mixtures and for collecting all solids. This method uses a Büchner funnel and flask:
- Place the Büchner funnel and filter paper into the Büchner flask, ensuring the paper fully covers the funnel holes.
- Seal the funnel with a rubber stopper or ring in the flask.
- Connect the flask’s side arm to a vacuum line or aspirator using thick-walled tubing, and turn on the vacuum.
- Wet the filter paper with a small amount of solvent identical to the mixture’s liquid to ensure it lays flat.
- Gently pour the mixture onto the filter paper while swirling the flask to prevent clumping.
- The vacuum suction draws the liquid into the flask, leaving solids on the filter paper.
What are Some Practical Examples of Filtration?
After understanding the definition and process of filtration, let’s explore its practical applications in daily life:
Household Filters
- Kettle Filter: Filters impurities like limescale, ensuring clean boiled water.
- Range Hood Filter: Captures grease particles during cooking, keeping the kitchen air clean.
- Faucet Filter: Removes large particles from tap water, preventing clogs and maintaining water quality.
- Air Purifier Filter: Removes dust, pollen, and smoke from the air using HEPA filters or activated carbon filters.
- Washing Machine Filter: Traps lint and debris during washing, preventing pipe clogs and extending the machine’s lifespan.
- Water Dispenser Filter: Filters out impurities and pollutants, ensuring safe drinking water.
Wastewater Treatment Plants
- Primary Filtration: Removes large solids like branches and plastic bags at the initial stage using screens.
- Secondary Filtration: Uses sand filters or biological filters to remove smaller particles and suspended solids.
- Advanced Filtration: Involves membrane filtration (e.g., microfiltration, ultrafiltration, reverse osmosis) to achieve higher precision in removing microorganisms and dissolved substances.
Aquarium Filtration
- Mechanical Filtration: Mechanical filtration uses physical methods to remove particles and suspended solids from the water, acting as the first line of defense in aquarium filtration systems. When water passes through filter pads, foam, or mesh, solid particles such as leftover fish food, sediment, and debris are trapped within the filtration media.
- Biological Filtration:Biological filtration relies on filter materials like ceramic rings or sponges inside the filter. These materials provide surfaces for beneficial microorganisms to colonize. These microbes carry out nitrification, converting ammonia (from fish waste) into nitrites, which are then further converted into harmless nitrates.
- Chemical Filtration: Chemical filtration removes dissolved substances and harmful chemicals from water through chemical reactions.
There are two main approaches: activated carbon, which adsorbs organic compounds and odors, and is commonly used to remove chlorine and chemical pollutants; and resin filters, which target specific chemicals like calcium and magnesium in hard water through ion exchange. - Filtration Equipment: Hang-on-back filters are mounted outside the aquarium, drawing water through tubes into the filter unit where mechanical, chemical, and biological filtration occurs, before returning clean water to the tank. These filters often combine multiple filtration methods, offering high efficiency and easy maintenance.
Internal filters are installed inside the aquarium, typically incorporating mechanical, chemical, and biological filtration. They are suitable for small tanks due to their ease of installation and operation.
Undergravel filters are placed at the bottom of the tank, using a layer of gravel or sand to conduct mechanical and biological filtration.
Water passes through the substrate for comprehensive filtration, making them ideal for larger aquariums or systems with substrate filtration.
👉read more:How Do Sponge Filters Work?
Groundwater Filtration
- Natural Filtration Process: The process of rainwater or surface water entering underground layers is known as infiltration. As water moves from the surface to underground, it passes through soil and rock fractures and pores, removing most suspended solids and particles.
While groundwater passes through soil layers, certain chemicals interact with soil particles. For instance, harmful substances in water may be adsorbed or neutralized by chemicals in the soil, or broken down by microorganisms present in the soil, which help remove organic pollutants and nitrogen compounds. - Well Water Filtration: When drawing water from underground aquifers, the well’s design also plays a filtration role. Wells typically have filters at the mouth to remove large particles and solids.
After extraction, the water undergoes further filtration and treatment to remove potential contaminants such as bacteria, heavy metals, and organic compounds. Common treatments include activated carbon filtration, UV disinfection, and chemical treatment.
Coffee/Tea Filtration
- Coffee: Drip coffee machines allow hot water to pass through coffee grounds, with the brewed coffee filtered through paper or metal mesh, capturing coffee grounds and solid particles, allowing only liquid coffee to pass through.
A French press steeps coffee grounds in hot water before using a plunger to press the grounds to the bottom. The metal mesh isolates the coffee grounds, leaving clear coffee liquid at the top.
Pour-over coffee involves placing a filter (paper or metal) in a dripper, with hot water passing through the coffee grounds and filter, allowing liquid coffee to flow into a container below. Paper filters typically capture finer coffee particles. - Tea: When brewing tea, teapots often have built-in filters or strainers to filter out tea leaves, allowing only the tea liquid to flow to the bottom.
Gold Panning
The process starts by using a sieve to remove large particles and impurities from river sand or ore. Next, vibrating screens further separate particles of different sizes, enhancing filtration precision.
The gold-bearing gravel or ore is then placed in a gold pan, where rotating and shaking help settle metal particles at the bottom while lighter materials are washed away.
Finally, gravity separation equipment may be used for further filtration, with additional refining through smelting and chemical processing to obtain purer metal if necessary.
Concerned About Your Water Quality at Home? How to Filter It?
Clean water is essential for daily consumption. Here are four methods to improve your water quality at home:
Filtration Membranes
Select appropriate membranes like microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), or reverse osmosis (RO) based on your needs.
Install them in systems like faucet filters or whole-house water treatment systems.
Regularly inspect and replace membranes as recommended by manufacturers.
Heating
Boiling water effectively kills bacteria, viruses, and other pathogens, though it doesn’t remove chemical contaminants.
Boil water for 1–3 minutes, or 3–5 minutes at high altitudes. Electric kettles offer a quick and convenient way to boil water.
Chemical Treatments
Activated carbon removes odors and organic compounds, while iodine tablets kill microorganisms.
Sodium-based coagulants like aluminum chloride remove suspended particles and sediments.
RO(Reverse Osmosis) Filters
Install an RO system with pre-filters, an RO membrane, and post-filters.
Water passes through the pre-filter, then the RO membrane, and finally the post-filter for thorough purification.
What is Filtration? | FAQ
Personal Hygiene Provider | Getek
You may not realize how closely filtration methods are connected to our daily lives. If impurities in air or water are not properly filtered, they can pose health risks.
If you find that your filters need frequent replacement or aren’t effective, consider the various filters offered by Getek, which provide excellent quality and comprehensive service.
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