Heavy metals could be in my water?!
It has been estimated that approximately 1 billion people do not have access to clean drinking water per year and 2 million people suffer from casualties each year due to contaminated water. This contaminated water is commonly found to have large concentrations of heavy metals due to heavy use of these metals in industrial settings. The more common metals being used are cadmium, chromium, lead, arsenic, and mercury which cause great concern as these metals are highly toxic to the human body. Scientists have decided to focus in on the problem of lead found in water as there is a high abundance of lead in a number of products from pigments to toys. Furthermore, lead can be found in drinking water of areas which used lead pipes or used lead solder in their infrastructure that over time corroded and contaminated the water quickly.
New technologies (MOFs)!?
Though this is a widely known and prominent issue, commercial methods of extracting heavy metals from water is inefficient and expensive. Scientists decided to focus their efforts on creating inexpensive metal-organic frameworks (MOFs) to clean the water of heavy metals. MOFs are materials made of metal nodes attached by organic chemical “struts”. These compounds are highly versatile and can be easily modified. Due to their cage-like structure they have porous regions which allow for large uptake of selective molecules. These structures can take more than their own weight of selected compounds and many of these structures combined can create a cohesive material that can extract heavy metals at very fast rates from water.
Potential solution for clean, metal-free water!
These newly created MOF-based materials were able to clean up a large concentration of lead and mercury from real world water samples. Even though these materials are made from metal nodes, it was shown that these materials would not break apart nor leech their own structures or the metals they uptake back into the water samples! Due to their structure, they allow for ease of separation of material and water sample, thereby leaving behind cleaner and drinkable water. Scientists now focus on creating variations of these MOF materials to improve their efficiency, target different heavy metals, and allow for these materials to be used in diverse environments.
By Candy Pham
Daniel T. Sun, Li Peng, Washington S. Reeder, Seyed Mohamad Moosavi, Davide Tiana, David K. Britt, Emad Oveisi, Wendy L. Queen. Rapid, Selective Heavy Metal Removal from Water by a Metal–Organic Framework/Polydopamine Composite. ACS Central Science, 2018; DOI: 10.1021/acscentsci.7b00605
Ecole Polytechnique Fédérale de Lausanne. “Removing heavy metals from water in a matter of seconds.” ScienceDaily. ScienceDaily, 14 March 2018. <www.sciencedaily.com/releases/2018/03/180314092258.htm>.
Picture is taken from Rapid, Selective Heavy Metal Removal from Water by a Metal–Organic Framework/Polydopamine Composite.