Comparative study on the adsorption of tetracycline and amoxicillin on glycine and poly-pyrrole functionalized multiwalled carbon nanotubes

Tetracycline (TC) and Amoxicillin (AMX) are widely used antibiotics for disease treatment. In this study, we developed a novel adsorbent by functionalizing multi-walled carbon nanotubes (MWCNT) with glycine (Gly) and polypyrrole (PPy). The materials were characterized using XRD, FTIR, FE-SEM, BET, and EDS analyses. Adsorption experiments were conducted under varying conditions, including initial pollutant concentration, pH, contact time, adsorbent dosage, and temperature. The optimal adsorption conditions were determined to be 0.005 g of adsorbent, 60 min of contact time, a temperature of 298 K, and a pH of 3. Under these conditions, the maximum adsorption capacities of MWCNT-Gly-PPy were 117.07 mg/g for TC and 102.09 mg/g for AMX. Thermodynamic analyses revealed that the adsorption process for both antibiotics was spontaneous and exothermic. The adsorption behavior was best described by the Langmuir isotherm model, while the kinetics followed the pseudo-second-order model. Cyclic adsorption-desorption experiments demonstrated the reusability of the adsorbent, with TC and AMX removal efficiencies of 81.3 % and 70.4 %, respectively, after 8 cycles. This research lays the foundation for the development of a highly efficient adsorbent, MWCNT-Gly-PPy, which demonstrates exceptional adsorption capacities and reusability for the removal of TC and AMX from contaminated water. Furthermore, the findings provide valuable insights into the adsorption mechanisms of antibiotics on functionalized MWCNTs, paving the way for the design of advanced materials for sustainable water treatment applications.