Obtaining modified chitosan nanofiber biomembranes for the removal of divalent lead ions in water contaminated by mining tailings.

This project studies the obtaining of chitosan nanofiber membranes to be applied in the adsorption of lead in aqueous and neutral media.
The chitosan material will be obtained through the enzymatic reaction of chitin obtained from shrimp residues
To obtain chitosan nanofibers, the electrospinning technique using polyvinyl alcohol will be used.
The polymeric materials obtained both in powder and membrane will be subjected to FT-IR characterization to evaluate the degree of deacetylation, in addition, the morphology and area of ​​the material will be known, using scanning electron microscopy techniques and BET surface area measurement. . Finally, the membranes will be evaluated in a flow cell at different flow rates in concentrations of 50 and 100 ppm of lead, in order to know their adsorption kinetics in flow and evaluate the degree of removal of lead ions, both for samples of synthetic water and water samples collected from mine tailings.

One of the main environmental problems of the mining activity is the contamination of the bodies of water in the areas surrounding said activity, mainly by heavy metals that are present in the mining tailings that diffuse towards the superficial waters. One of these polluting metals is lead, whose accumulation in the body produces serious diseases related to an increased risk of cancer, cerebrovascular diseases, kidney failure, decreased memory and high blood pressure. For children, their bodies absorb lead more quickly, which can cause premature births, low birth weight, limited hearing and other brain damage that affects learning and a low IQ level. The Environmental Protection Agency of the United States (EPA) affirms that lead is the most serious environmental hazard for the health of children under 6 years of age, for which reason it recommends as a maximum limit a value that does not exceed 15 g/L, some studies even suggest that this limit should be below 10 g/L.
For the removal of this and other contaminating metals present in the water, different technologies are being used, among which those of precipitation - flocculation, adsorption and biosorption stand out. Regarding the precipitation and coagulation techniques, it is necessary to use reagents in moderate amounts that alter the physicochemical properties of the water, generating excess chloride, nitrate, iron and aluminum ions. For batch adsorption techniques, the problem of separating the microparticles that have retained the polluting metals by filtration arises, which increases the cost of purification.
Therefore, it is necessary to develop a technology that is made up of a material that has the ability to efficiently capture divalent metal ions.