A novel porous adsorbentbased on cactus powder/ionic liquid for the removal of nimesulide from wastewater

This work proposes the fabrication of a novel adsorbent based on agro-waste resources with functional adsorption properties to remove a recalcitrant pollutant, such as Nimesulide, from water effluents. An aerogel system, produced through supercritical carbon dioxide drying, was made of cactus powder and 1-ethyl-3-methylimidazolium dicyanamide ionic liquid. The use of ionic liquid allowed to obtain a 3D porous structure showing a mean pore size of 0.12 μm. Its incorporation into cactus-based aerogel improved the adsorption capacity, allowing a drug removal of 88% compared to pristine aerogel, which showed a removal capacity of 15%. Different parameters such as temperature, contact time, pH, initial drug concentration, adsorbent dosage, and salt presence were changed, and their effects on the removal of Nimesulide were assessed. According to the Langmuir model, the maximum adsorption capacity is q_m = 109.9 mg/g, while the kinetic data obeyed the pseudo-second-order model. The reusability tests proved that the adsorbent can be reused for up to 10 cycles without significant adsorption performance loss.