Nanostructured diatomite and its potential for the removal of an antibiotic from water

Abstract

The objective of this research was to perform characterization of Mexican diatomite through different techniques and to analyze its efficiency in the adsorption of ciprofloxacin present in synthetic water. Mexico has large deposits of diatomite land that have not been well characterized; characterization is important in order to increase the use of this biomaterial in more specialized applications, such as the adsorption of emerging pollutants. Some of the emerging contaminants found in wastewater and surface water are antibiotics, such as ciprofloxacin. With the characterization, it was confirmed that diatomite is a nanostructured material composed of silicon oxide. Different forms of diatoms were found as well, corresponding to the species Discostella, Amphipleura and Cymbopleura, which showed a porous structure on the order of 50–380 nm with a surface area of 27·51 m2/g. The variables that were used to corroborate the adsorption efficiency of ciprofloxacin onto diatomite were the concentration of ciprofloxacin and initial pH for a period of time of 12 h. In this research, the data suggest a good affinity between ciprofloxacin and the diatomite. The adsorption efficiency at pH 9 was between 18 and 34%, and in the case of pH 6, it was between 64 and 75%.