Chemistry

What is the difference between liquid detergent and powdered laundry detergent? It’s not just the obvious ones

Credit: Pixabay/CC0 Public Domain

When shopping for laundry detergent, the sheer number of choices can be overwhelming. All of these products will make your laundry a little cleaner. But what will give you the best results for your outfit and your budget?

Want more whites? Are enzymes necessary? So, what is the difference between powder detergent and liquid detergent?

As is often the case, knowing more about the chemistry involved can help answer these questions.

What is detergent?

The active ingredients in both laundry powders and liquids are “surfactants”, also known as detergents (hence the product name). These are usually charged or “ionic” molecules that have two distinct parts in their structure. One part interacts well with water and the other part interacts with oil.

This useful property allows surfactants to lift grease and dirt from fabrics and suspend them in water. Surfactants can also form foam.

Metal salts dissolved in water can limit surfactant performance. So-called hard water contains a lot of calcium and magnesium salts, which makes it easier for soap scum to form.

Therefore, modern laundry detergents contain phosphates, water softeners, and other metal “sequestrants” to prevent the formation of soap scum. Phosphates can cause algal blooms in freshwater environments. This is why modern detergent formulations contain low amounts of phosphates.

Many products also contain optical brighteners. These chemicals absorb ultraviolet light and emit blue light, resulting in a “whiter” or “brighter color” phenomenon.

Laundry detergents usually contain fragrances. These are not essential to the cleaning chemistry, but they add a fresh look to your clothes.

Finally, some laundry detergents contain enzymes, but more on that later.

What’s in laundry powder?

The ingredients that prevent detergent and soap scum are the most important ingredients, but they are not the most abundant. The main component of the powder is salt (such as sodium sulfate), which adds bulk and prevents the powder from clumping.

Another common salt added to laundry powder is sodium carbonate, also known as laundry soda. Washing soda (a type of baking soda) chemically modifies grease and dirt so that it dissolves in water.

Laundry powders often also contain oxidizing agents such as sodium percarbonate. This is a stable combination of washing soda and hydrogen peroxide. An additive known as tetraacetylethylenediamine activates the percarbonate, creating a mild bleaching effect.

Chemically, powders have the advantage that their components can be formulated and mixed, but kept separate in solid form. (Laundry powders usually contain different types of granules.)

What’s in the washing liquid?

The main component of washing liquid is water. The remaining ingredients must be carefully considered. These must be stable in the bottle and work together during cleaning.

These include ingredients similar to powders, such as alkali salts, sequestering agents, water softeners, and surfactants.

Surfactants found in liquid products are often listed as “ionic” (charged) and “nonionic” (uncharged). Nonionic surfactants may be liquid by default, making them unsuitable for powder formulations. Nonionic surfactants are better at suspending oils in water and do not form soap scum.

Liquid detergents also contain preservatives that prevent the growth of microorganisms that can ruin the mixture.

The inside of your washing machine is also affected by microorganisms. Liquid products cannot contain peroxide (mild bleach), which is present in powder products. Peroxide kills microorganisms. Liquid detergents do not contain peroxide, which increases the chance of mold biofilm forming in the machine or transferring bacteria between clothes.

As an alternative to peroxide, the liquid usually contains only optical brighteners.

Liquids have one advantage over powders. It can be added directly to the stain before placing the item in the washing machine.

A modern “convenience” version of liquid milk is a highly concentrated detergent pod. These products, which resemble colorful, sweet treats, are known to be dangerous for young children and people with cognitive disabilities.

The pod also removes the option to add less detergent if you’re running lower loads or just want to use less detergent in general.

So what about enzymes?

Enzymes are naturally evolved proteins found in laundry products to remove certain stains. Chemically, they are catalysts, meaning things that accelerate chemical reactions.

Enzymes are named by adding “-ase” after the molecule they act on. For example, lipases break down fats (lipids), proteases break down proteins, and amylases and mannanases break down starches and sugars.

These enzymes are derived from organisms that live in cool climate regions and help them function in cold wash water.

Excessively hot wash cycles can damage or denature the enzyme structure, rendering it ineffective for enzymatic cleaning. Consider that egg whites change from translucent to white during cooking. This is protein denaturation.

If the detergent contains enzymes, the washing temperature should not be too hot or too cold. As a guide, standard laundry tests use temperatures of 15-20°C.

Which is better, powder or liquid?

We base consumer choices on performance, psychology, cost, fragrance, environmental friendliness, and convenience.

It’s worth trying out different products to find what works best for you, your needs, your household budget and environmental considerations such as recyclable packaging.

I personally wash at 20°C using half the recommended dose of a pleasantly scented laundry powder packaged in recyclable cardboard and containing various enzymes and activated peroxide sources .

Knowing a little about chemical reactions can go a long way in cleaning your clothes.

However, laundry detergent manufacturers do not always disclose the full ingredient list on product packaging.

If you want to know more about what’s in the product, you should visit the product website. You can also find out more by reading a document called a Safety Data Sheet (SDS). All products containing potentially hazardous chemicals require an SDS.

Presented by The Conversation

This article is republished from The Conversation under a Creative Commons license. Read the original article.conversation

Quote: What is the difference between liquid and powder laundry detergent? That’s just the obvious facts Retrieved November 11, 2024 from https://phys.org/news/2024-11-difference-liquid-powder-laundry-detergent.html (November 11, 2024) Not.

This document is subject to copyright. No part may be reproduced without written permission, except in fair dealing for personal study or research purposes. Content is provided for informational purposes only.

Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button