How to recover silver from laundry waste water

Did you know that some of your clothes might actually be made from silver?

This sounds fascinating doesn’t it?

The use of silver nanoparticles in clothing is becoming quite common as manufacturers use it in clothing for its anti-odour properties as it kills odour-causing bacteria.

But when your clothes are laundered, some of the silver particles come off and ends up in your washing machine waste water. It then culminates in the environment and poses eco-toxicological risks and possibly harming aquatic life.

The scientists also used an ion-exchange resin to draw out about 99 percent of the silver depending on the pH concentration and concentration of competing ions.

Removing silver from the waste water is therefore an environmental necessity and scientists have attempted to do just that.

One group of scientists have reported that the amount of detergent plays a big role in how much silver can be removed from laundry waste water.

Removing silver nanoparticles from waste water is not an easy task because of low concentrations of silver, high-concentration of competing ions and uncertainty about the forms of silver that may be present in the water.

Previous studies have shown that the interaction between silver and ion is highly selective for silver but there has been no investigation into the role of detergent chemistry which could interfere with the method.

For this study, researchers analysed how silver interacts with detergent ingredients.

Silver mainly exists as a positively charged ion and this form will interact with many detergent compounds under certain conditions.

For example, the positively charged ions of silver will interact with the negatively charged ions of the detergent under different pH ranges.

The scientists also used an ion-exchange resin to draw out about 99 percent of the silver depending on the pH concentration and concentration of competing ions.

They then tested the resin with detergent compounds and found that that the resin can be used over five washing cycles and it maintained its ability to remove silver.

However, the efficiency of the resin was negatively impacted by the addition of other products such as bleaching and water-softening products.

This study demonstrated a closed-loop sustainable method of recycling and reusing resin and a regenerant solution over five wash cycles.

This is great news for us and the environment as we can continue wearing anti-bacterial clothing and protect the environment at the same time.

Source: ACS Sustainable Chemistry & Engineering,