Synthesis of carbon nanotubes grafted with PEG and its efficiency for the removal of phenol from industrial wastewater

Carbon nanostructures have a great potential in various applications. They are considered as promising sorbents of contaminants owing to their unique physical and chemical behaviors. In this work, a hybrid adsorbent was successfully prepared by oxidizing carbon nanotube (CNT) and grafted with polyethylene glycol (PEG). The performance of the hybrid material (CNT/PEG) as an adsorbent was investigated for the phenol removal in a batch system. The effects of contact time, initial solution pH, the initial concentration of phenol, and adsorbent dosage on the efficiency of phenol removal were investigated. The phenol adsorption by CNT/PEG was pH-dependent and under optimum conditions, high adsorption efficiency (≈100 %) was achieved at a contact time of 30 min. The magnitude of R² acquired with the pseudo-second-order model is high (>0.99) which indicates the process follows this model. Both the Langmuir and Freundlich isotherm models show a good fit to the adsorption experimental data. However, Freundlich model shows a better fit to the experimental results than the Langmuir model (R² > 0.98). The prepared hybrid material (CNT/PEG) demonstrated to be an efficient adsorbent for removal of phenol from water as well as for simultaneous removal of phenol with pollutants such as Cu, Hg, Cr, Fe, Co, Ni, Al and Pb from industrial wastewater.