UABDivulga - Barcelona recerca i innovació

The presence of toxic metals in industrial or municipal waste-water requires prior monitoring and an effective treatment strategy according to the contamination level for the further use of these waters or their confinable delivery to rivers, lakes, etc., following the permissible limits of contamination stated by regulatory agencies.
 
Although calorimetric, fluorimetric and electrochemical techniques, as well as atomic adsorption spectroscopy, have been developed for toxic metal detection and continue to be the main techniques used for metal determination, these methods are expensive and require trained personnel. In addition to these techniques, other chemical methods are also used.
 
Advances in nanoscale science and engineering are providing new opportunities to develop more cost-effective and environmentally acceptable water purification processes through the use of nanomaterials. Many different nanoscale materials such as zeolites, metal oxides, carbon nanotubes and enzymes, various noble metals and titanium dioxide have been explored for water remediation.
 
Nanomaterials from transition metal hydroxides or oxides, especially iron, have been extensively studied for monitoring, remediation and water pollution prevention. In the past ten years, biomaterials such as CaCO₃ have been added to the list of potential nanomaterials for water treatment.
 
Calcium carbonate is one of the most important and cheapest biomaterials in nature. Many organisms produce calcium carbonate with unique hierarchical structures and fascinating characteristics in their tissues for a variety of functions. Calcium carbonate has ideal biocompatibility and biodegradability properties.
 
In our group, we have developed a new and simple multifunctional system based on calcite-polyethyleneimine nanostructure rod formations which shows the sensing and removal of Pb²⁺. This system is able to detect up to 1 ppm Pb²⁺. The maximum of Pb²⁺ removal capacity reported here is higher than other capacities reported previously, in which the materials used were not as cheap nor as biodegradable as calcite.


Figure 1. A) Outline of new system's functioning. B) Chemical reaction which is produced in the new system.