Soaps, detergents, shampoos, are just some examples of compounds that contain surfactants

Like every medal there is a bright side and a dark side, in our case, today, we are talking about both the bright side, that is, cleaning products that fulfill a noble and dutiful task, as well as on the dark side, which concerns the environmental impact of the discharge of surfactants into rivers, lakes and seas.

What are surfactants

Surfactants, also known as surfactants, are chemical compounds that are commonly used in detergents, such as shampoo, soaps, detergentsand many other personal and domestic cleaning products.

Their main function is to lower the surface tension between two immiscible phases, such as water and oil , allowing them to mix into a homogeneous solution.

This ability makes them effective at dispersing grease and dirt, facilitating cleaning and eliminating impurities. Surfactants can be of different types:

- as anionic

- cationic

- non-ionic

- amphoteric

each with specific properties depending on the desired application.

Categories and differences between surfactants

Surfactants can be divided into several main categories based on their polarity and electrical charge. The main categories of surfactants are:

Anionic surfactants

These surfactants have a negative charge when dissolved in water. They are commonly used in laundry and dish detergents, as well as soaps. Examples include sodium lauryl sulfate (SLS) and sodium lauryl sulfonate (SLES).

Cationic surfactants

Unlike anionic surfactants, cationic surfactants have a positive charge in an aqueous environment. They are often used as additives to fabric softeners, hair conditioners and fabric detergents. Examples of cationic surfactants include quaternary ammonium chlorides.

Non-ionic surfactants

These surfactants have no electrical charges and are often used in delicate detergents, such as detergents for sensitive skin or dishwasher detergents. Examples include ethoxylated fatty alcohols (AEOs) and ethoxylated nonylphenols (NPEs).

Amphoteric surfactants

They can have both positive and negative charges under different pH conditions. They are commonly used in hair products, such as shampoos and conditioners. A common example of an amphoteric surfactant is cocamidopropyl betaine.

The differences between surfactants mainly concern their electrical charges and the properties that these give to the compounds.

Additionally, the type of surfactant used can impact its effectiveness for specific applications, such as fat removal, foaming, and the ability to be stable under different conditions of pH and temperature. The choice of surfactant will depend on the specific needs of the product and its intended use.

The history of surfactants

The use of natural surfactants, such as soap, dates back thousands of years. The first attempts to clean and wash objects pushed man to use mixtures of oils and fats of animal and vegetable origin, which already contained natural surfactant compounds.

These surfactants present in the soap allowed the surface tension of the water to be reduced, making cleaning easier.

However, the large-scale production of synthetic surfactants, such as those used today, began during the 20th century, with major developments in industrial chemistry and materials first.

In fact, the first synthetic surfactants were developed during the first half of the 20th century and were mainly used in the detergent and soaps.

There is no single inventor of synthetic surfactants, but credit goes to many scientists and researchers who have helped develop and refine these chemical compounds over time . Their discovery and application have had a significant impact on the cleanliness, hygiene and production of a wide range of chemicals and modern consumer goods.

What does the discharge of surfactants into the environment mean

The discharge of surfactants into the environment can have several negative effects, as these chemical compounds can be harmful to aquatic and terrestrial ecosystems.

Let's see some of the main environmental problems related to the discharge of surfactants into the environment:

Water pollution

Surfactants can enter water bodies through domestic and industrial wastewater. These compounds can alter the surface tension of water, reducing the ability of organisms to glide or float.

This may have negative effects on some aquatic species, such as insects or small animals that move on the surface of the water to feed or reproduce.

Toxicity to aquatic life

Some surfactants, especially non-biodegradable ones, can be toxic to aquatic organisms such as fish, invertebrates and aquatic plants. These compounds can damage organisms present in aquatic ecosystems, altering their physiology and their ability to survive and reproduce.

Foaming

Excessive discharge of surfactants can lead to foaming on the surface of the water, especially at discharge sources such as rivers or lakes. This foam can interfere with oxygen transport, create obstructions and obstacles for wildlife, and become an aesthetic problem.

Soil pollution

If surfactants are absorbed into the soil, they can contaminate groundwater or negatively affect soil microorganisms, compromising soil health and fertility.

What are biodegradable surfactants

Biodegradable surfactants are chemical compounds that can be easily broken down and decomposed naturally by biological organisms present in the environment, such as bacteria and other microorganisms . This characteristic makes them less harmful to the environment than non-biodegradable surfactants, since they degrade quickly and transform into less toxic substances.

Let's see what the main biodegradable surfactants are:

Sugar-based surfactants

They are obtained from plant sources such as corn, sugar cane or coconut. They are considered biodegradable and often used in eco-friendly and sustainable cleaning products.

Amino acid-based surfactants

They are derived from amino acids, the building blocks of proteins. They are biodegradable and commonly used in personal hygiene products, such as shampoo and mild cleansers.

Surfactants based on vegetable oils

Some surfactants can be obtained from the saponification of vegetable oils such as palm oil or coconut oil. They are biodegradable and used in cleaning and skin care products.

Enzyme surfactants

They are based on enzymes, which are highly biodegradable natural proteins. They are often used in laundry and dishwasher detergents.

Surfactants of natural origin

Some surfactants can be extracted from natural sources such as soapworts (Sapindus spp.) or other trees and plants.

When choosing products containing surfactants, it is always advisable to look for those with "biodegradable" or "eco-friendly" labels to help reduce the environmental impact of their use.