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In last week’s article, we explored what buffer solutions are, and we’re taking it one step further this week as we look at uses of buffer solutions.
To briefly recap, buffer solutions are aqueous solutions of a weak acid with its conjugate base, or a weak base with its conjugate acid. Buffer solutions are incredibly useful as they have the ability to maintain a stable pH balance and resist change, even when a strong base or acid is introduced.
What Are The Main Uses of Buffer Solutions?
Many chemical reactions require a stable pH to be effective, so buffer solutions have many uses. Industrially, buffer solutions are used in:
Yes, buffer solutions are used in the production of alcohol. They are added before fermentation – the conversion of sugar to alcohol – begins to keep the pH at a specific level and inhibit the acidity, which would ruin the product. Since the pH of a solution changes during fermentation process, buffer solutions are an important element in every alcoholic drink.
The same applies to baking bread, when the dough’s pH decreases and becomes more acidic. In this case, milk and flour are the buffering agents as they combat the drop in pH by releasing carbon dioxide.
Many fabric dyeing processes use buffer solutions in order to maintain the correct pH for the dye. The incorrect pH can affect the colour of the dye and its ability to properly dye a fabric. Many of the different processes involved in dyeing fabrics require a balanced pH, for example scouring cotton requires strong alkalinity, and buffer solutions are also used in bleaching and finishing.
Manufacturing Personal Hygiene & Cosmetic Products
Buffer solutions are used in the manufacture of many cosmetic and personal hygiene products in order to maintain a pH that’s neutral or even slightly alkaline. The buffer solution prevents the products becoming too acidic or too alkaline, as this could cause skin irritations. For example, soap has a naturally high pH so are typically buffered to a pH of around 5.5, which is the skin’s natural pH.
Another example is shampoo. Citric acid or sodium citrate are commonly used as buffers to maintain a slightly acidic pH, which works against the natural alkalinity of the detergents in shampoo that could burn the scalp.
Baby lotions use a buffer solution which maintains a slightly acidic pH of around 6. This helps to prevent the growth of bacteria and nappy rash.
Other Uses of Buffer Solutions
- Printing – the pH of paper and inks are regulated to ensure that the ink penetrates the paper and dries properly
- Leather – maintaining a specific pH balance using buffer solutions in a tanning bath helps to determine the texture of the finished leather
- Household products – buffer solutions are used in the manufacture of laundry detergents and washing up liquids to prevent the breakdown of natural ingredients
- Calibrating equipment
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