Cotton textile waste valorization for removal of tetracycline and paracetamol alone and in mixtures from aqueous solutions: Effects of H3 PO4 as an oxidizing agent.

The use of waste and by-products locally available in large quantities and at low cost as adsorbents can be considered an appropriate approach for improving waste management and protecting the environment. Cotton textile waste was used to prepare adsorbents (MC) via pyrolysis followed by a chemical modification with H3 PO4 . MC samples were characterized by scanning electron microscopy, FTIR spectroscopy, and N2 adsorption-desorption isotherm. The results revealed that MC treated with 1 M H3 PO4 (MC1 ) showed an excellent adsorption performance. The single and binary adsorption of tetracycline (TC) and paracetamol (Pa) onto MC1 were studied. In a single system, TC was better adsorbed than Pa and maximum adsorption capacities qm are 87.7 mg/g and 62 mg/g, respectively. The adsorption follows the Langmuir and pseudo-second-order kinetic models. For a binary system, the experimental data indicate that Pa (44.04 mg/g) is better adsorbed than TC (24.13 mg/g). Adsorption equilibrium data of TC and Pa evaluated by the selectivity extended-Langmuir model in which selectivity factor was introduced provided good correlation results with the binary adsorption data. Cotton textile waste is potentially promising for the preparation of effective adsorbents for the removal of pharmaceutical residues in aqueous solutions. PRACTITIONER POINTS: Valorization of cotton textile waste into adsorbents. Adsorbents were prepared by pyrolysis at 600°C followed by chemical modification in the presence of H3 PO4 . Removal of tetracycline (TC) and paracetamol (Pa) alone or in mixtures by adsorption. Adsorbent showed high-capacity adsorption of the TC and Pa even in a mixture from solutions at low concentrations. The Langmuir and selectivity extended-Langmuir models describe the adsorption of TC and Pa alone and in mixtures, respectively.