Removal of Organic Pollutants – Mycotoxin Ochratoxin A and Pharmaceutical Ketoprofen by Cationic Surfactant Modified Kaolinite

The potential of kaolin modified with a cationic surfactant - hexadecyltrimethylammonium (HDTMA) bromide as an adsorbent for the removal of two different contaminants: mycotoxin - ochratoxin A (OCHRA) and the pharmaceutical - ketoprofen (KET) from buffer solutions (pH 7) was investigated. The amount of HDTMA used for modification was equal to 50% of kaolin's cation exchange capacity (CEC). The obtained material (HKR-50) was characterized using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry/thermogravimetric analysis (DSC/TG), and scanning electron microscopy (SEM), confirming successful surface modification of kaolinite with HDTMA. Adsorption experiments demonstrated that HKR-50 exhibited significantly enhanced removal efficiency for both OCHRA and KET compared to unmodified kaolin. Nonlinear adsorption isotherms suggested a complex mechanism involving both hydrophobic and electrostatic interactions between contaminants and HDTMA ions. The data fit well to the Langmuir model, with maximum adsorption capacities of 2.57 mg/g for OCHRA and 1.40 mg/g for KET. These findings indicate that surfactant-modified kaolin is a promising and cost-effective adsorbent for the removal of mycotoxins from animal feed and pharmaceuticals from contaminated water, contributing to environmental protection and public health.