In small quantities, certain heavy metals such as copper, zinc and chromium are required by the human body. In larger quantities, heavy metals are toxic, with lead, mercury, arsenic and cadmium among the more popularly known toxic heavy metals. Large quantities of heavy metals in our waste water pose great risks to the environment, animals and humans alike.
Heavy metals have the ability to dissolve in wastewaters and when discharged into surface waters, can be ingested and concentrated as they travel up the food chain. Dissolved heavy metals can also seep into groundwater, resulting in the contamination of drinking and irrigation water.
Globally, the need for management of water quality and sustainability has spawned wide–ranging environmental legislation in most developed countries. Technology advances, similarly, have dramatically progressed our ability to treat contaminated waters and remove these metals.
Working in the technology category, Gabriel Ramirez Monter, a graduate researcher at the National Polytechnic Institute (IPN) in Mexico, has developed a biological solution to removing heavy metals from water.
Monter has designed microbiological structures called dendrimers, which are highly branched molecules in the shape of a tree with multiple branches.
“Dendrimers adhere and spread on a microfiltration membrane; i.e., thin sheets of porous material that are not normally capable of retaining heavy metals due to their pore size. Once placed, it achieves total removal of heavy metal ions in the same way a marine anemone would act, using tentacles to concentrate and catch food; in this case, the branches of the dendrimers capture pollutants, ” says Monter.
A microfiltration membrane has been converted into a nanofiltration membrane that can easily capture and remove the heavy metals. These membranes are durable, washable and reusable.
The application of this new technology may significantly reduce the overall percentage of heavy metals in waste water. If successful, this will have a substantial impact on the environment as well as public health.
Monter’s dendrimers are still in the entrepreneurial phase in Mexico and thus a while away from worldwide release.