Fabrication of novel multifunctional copper-functionalized hemp fibers to remove anionic dye and non-steroidal anti-inflammatory drugs from wastewaters.

This research aims to design a novel selective and multifunctional adsorbent based on Al/Cu modified hemp fibres as a novel and multifunctional adsorbent for removing different classes of pollutants. The adsorbent, which was widely characterized, was shown to be more effective in removing anionic dyes compared to cationic ones. Among the tested dyes, methyl orange (MO) was selected to understand how different parameters, such as temperature (20-80 °C), contact time, pH (2-12), initial dye concentration (50-300 ppm), salinity and adsorbent dosage (1-10 g/L) affect the removal capacity. The Langmuir model greatly describes the adsorption data with a q_m = 338.98 mg/g. Thermodynamic calculation proved that the adsorption process is spontaneous (negative ΔG) and endothermic (positive enthalpy) while the adsorption process is governed by either film or pore diffusion. The Design of Experiment algorithm was adopted to predict the recovery of MO through a response surface model by varying simultaneously the pH, temperature and initial dye concentration, in accordance with the experimental data. It was demonstrated the multifunctional properties of the produced adsorbent since it showed a great selectivity in removing two anti-inflammatory drugs (91% for piroxicam and 34% for diclofenc sodium salt). Finally, the selective removal of different anionic dyes in a mixed solution was proved, following the order methyl orange>congo red>acid yellow 17. The reported approach presents a sustainable, low-cost option for the preparation of novel and effective adsorbents with interesting properties to achieve remarkable adsorption of anionic dyes and anti-inflammatory drugs with a great reusability.