With incidents such as the water crisis in Flint, Michigan, many people are understandably concerned about the quality and safety of the water they drink. Others simply dislike the metallic taste of tap water. While these concerns have prompted some to buy case after case of disposable water bottles, others have opted for a much greener option: a water bottle with a filter.
Water bottles that come with filters decrease the amount of plastic that a user consumes, and, as a result, both expenditures and his or her carbon footprint. Also, water bottles with filters come in handy while away from home; while you might have a filter on your tap at home, you cannot always be certain of water safety—or taste—on-the-go.
But how does a water bottle with filter work? Each water bottle is fitted with a filtration system that can remove impurities and contaminants that tap water might contain. The specific filtration mechanism depends on the make of the water bottle with filter; some filter the water as you fill up the bottle, while others filter the water as you consume it.
But in general, most water bottles with filters use a carbon filter. We’ve detailed the process below.
- Activate carbon - Carbon filters use activated carbon, also known as activated charcoal, to remove impurities from water. If you have ever observed black specks at the bottom of your water bottle with a filter, that is carbon. These black specks are common, and can come with new as well as older filters.
However, regardless of the presence of these black specks, water bottle filters should frequently be changed to ensure proper filtration. Activated carbon has been oxygenized (treated with oxygen), often through physical modification and degradation in a controlled furnace, to be highly porous. This process increases the ratio of the total surface area per unit of volume and allows the next important process in water bottle filtration—adsorption—to take place.
- Adsorption - Adsorption is the process of attachment of atoms, ions and/or molecules to a surface due to chemical Because activating the carbon opens pores, a gram of activated carbon has roughly 300 to more than 2,000 square meters of surface area available for bonding. Pollutants in the water adsorb to water filters containing activated carbon because their attraction to carbon atoms is stronger than the forces maintaining their dissolution in water.
This idea is essentially how water bottles with filters work: by increasing the number of bonding sites per volume unit of carbon, activated carbon in water bottles physically removes harmful contaminants by binding to them. Ionized carbon has four binding sites normally, which is relatively high among all chemical elements, and explains why it makes for an effective filtration system.
- Filtration - It is precisely because carbon filters remove contaminants from drinking water by binding to them that it is important to change your filter (depending on how often you use the water bottle) according to the company’s instructions. Filtration based on chemical attraction to carbon means that impurities in the water that are neutral (no negative or positive charge) or non-polar (or hydrophobic, with a relatively low attraction to polar substances such as water) are organic (sometimes indicated by a high carbon and hydrogen composition), and have high molecular weights are easily adsorbed and thus, removed from your drinking water. By the same rules, water bottles with activated carbon filters do not effectively remove salts, minerals and inorganic molecules from water.
In addition to adsorption, carbon surfaces are also host to important chemical reactions that remove certain contaminants from water. One that is of interest to users of water bottles with filters is chlorine removal. Chlorine reacts with carbon to produce chloride ions, which binds them to the carbon filter and removes the chemical from water.
Water bottles with filters also remove particles ranging from half a micrometer (one-thousandth of a meter) to 50 micrometers. Furthermore, the effectiveness of a filter depends both on the surface area of the activated carbon, but also on how quickly the water flows through the filter. The longer it takes for water to flow through the filter, the more time it is exposed to the activated carbon, and the more contaminants that are ultimately removed from the water.
Water bottles with filters are increasingly becoming more popular. They’re greener, they’re cheaper, and they offer a convenience unmatched by other water bottles. As demand for them grows, drinkware companies like Custom Water Bottle have begun to make custom plastic bottles for sale, making for great gifts and team gear. Do your research and find the one that is best for you!
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