Research shows the potential of coconut charcoal in water decontamination

Coconut water is a symbol of the country’s beach culture. The cold drink helps refresh tourists and locals alike and withstand the heat, especially in the summer. The problem is that 250 milliliters (ml) of the liquid result, on average, in 1 kilo of waste, formed by the coconut shell, which is not consumed. And this garbage takes 10 to 15 years to decompose. A survey by the Fluminense Federal University (UFF) sought a solution for this waste, which not only prevented its destruction and disposal in a landfill (or in nature) but also contributed to the depollution of the water consumed by the population. In his doctoral thesis, researcher Bruno Salarini Peixoto, under the guidance of Professor Marcela de Moraes, from the Institute of Chemistry at UFF, developed a more economical and efficient technique to transform green coconut into magnetic charcoal and also to use this product as a decontaminant. According to Marcela de Moraes, the coconut is initially transformed into biochar through its burning. Subsequently, it undergoes an activation process and, finally, magnetic nanoparticles are added to the product. This product is capable of adsorbing, that is, it is capable of attracting water contaminants to its surface. And also, once magnetized, it can be removed from the water (after adsorbing the pollutants) through magnets. She explains that removing coal from the water by magnetism is cheaper than the filtration method. Medicine residues Magnetic biochar is even more important if one considers the type of role it can play in cleaning water: the removal of medication residues, including antibiotics, in treatment plants. “The consumption of drugs [no mundo] increased. We take a lot of medicine and everything we take ends up being excreted, somehow. In our urine, for example. And there is also the irregular disposal of drugs”, says Marcela. The researcher points out that traditional methods of cleaning water in treatment plants are unable to eliminate this type of pollutant, called “emerging contaminant” (that is, contaminants that have gained importance recently). “The water and sewage treatment plants that we have today were not developed to remove these substances. So these substances pass through the treatment plant and they come back to us. The trend is that, if we do not change this scenario, the amount of these substances will increase more and more. This means that we would be drinking water with antibiotics, in ever-increasing doses”, explains Marcela. According to the researcher, charcoal can be added directly to the water treatment tank or placed in the pipe through which the water passes after being treated by the station. “Right now we are evaluating the possibility of trapping the coal and making the water pass through it. We are looking to patent the production process for this biochar and the next step would be to get in touch with the water treatment plant here in Niterói [município do Grande Rio de Janeiro, que é sede da UFF], so that we can start applying the material”. The research was funded by the Research Support Fund of the State of Rio de Janeiro (Faperj), by the National Council for Scientific and Technological Development (CNPq) and by the Coordination for the Improvement of Higher Education Personnel (Capes).

Agência Brasil