Precipitation of calcium-aluminum-cetyltrimethylammonium bromide nanoparticles on the sand to generate novel adsorbent for eliminating of amoxicillin from aquatic environment

The main focus of this work is changing inert sand into a reactive material by adding new binding sites (layered double hydroxide nanoparticles) to its surfaces. The main ingredients used to create these nanoparticles are surfactant, chicken eggshells (solid waste), and alum (cheap material). The efficacy of modified sand, also known as “sand coated with (Ca/Al-CTAB)-LDH,” was examined by removing amoxicillin from an aqueous solution. Two surfactants (CTAB and DK1) were investigated and measurements proved that the sorbent with CTAB has high ability to remove the adopted antibiotic with efficiency > 80 % at best synthesis conditions of pH 12, CTAB dosage 0.05 g, Ca/Al ratio 2 and sand dosage 1 g/50 mL. According to isotherm models, the sorption curve for amoxicillin onto modified sand is “favorable” with a maximum sorption capacity of 43.642 mg/g. The pseudo first-order model was more efficient in the fitting of kinetic results. Characterization analyses showed that the structure of coated sand has significantly changed due to the formation of a plate-like layer made up of loosely aggregated micrometric plates caused by (Ca + Al + CTAB) LDH nanoparticles. This can result in a significant increase in the removal of antibiotics.