Temperature-responsive graphene oxide/N-isopropylacrylamide/2-allylphenol nanocomposite for the removal of phenol and 2,4-dichlorophenol from aqueous solution

In this study, a novel thermo-responsive polymer was synthesized with efficient grafting of N-isopropylacrylamide as a thermosensitive polymer onto the graphene oxide surface for the efficient removal of phenol and 2,4-dichlorophenol from aqueous solutions. The synthesized polymer was conjugated with 2-allylphenol. Phenol and 2,4-dichlorophenol were monitored by ultra-performance liquid chromatography system equipped with a photodiode array detector. The nanoadsorbent was characterized by different techniques. The nanoadsorbent revealed high adsorption capacity where the removal percentages of 91 and 99% were found under optimal conditions for phenol and 2,4-dichlorophenol, respectively (for phenol; adsorbent dosage = 0.005 g, pH = 8, temperature= 25 degrees C, contact time = 60 min; for 2,4-dichlorophenol; adsorbent dosage = 0.005 g, pH = 5, temperature = 25 degrees C, contact time = 10 min). Adsorption of phenol and 2,4-dichlorophenol onto nanoadsorbent followed pseudo-second-order kinetic and Langmuir isotherm models, respectively. The values of Delta G (average value = - 11.39 kJ mol(-1) for phenol and 13.42 kJ mol(-1) for 2,4-dichlorophenol), Delta H (- 431.72 J mol(-1) for phenol and - 15,721.8 J mol(-1) for 2,4-dichlorophenol), and Delta S (35.39 J mol(-1) K-1 for phenol and - 7.40 J mol(-1) K-1 for 2,4-dichlorophenol) confirmed spontaneous and exothermic adsorption. The reusability study indicated that the adsorbent can be reused in the wastewater treatment application. Thermosensitive nanoadsorbent could be used as a low-cost and efficient sorbent for phenol and 2,4-dichlorophenol removal from wastewater samples.

Automated summary

In this study, a novel thermo-responsive polymer was synthesized and grafted onto the surface of graphene oxide for efficient removal of phenol and 2,4-dichlorophenol from aqueous solutions. The nanoadsorbent demonstrated high adsorption capacity, achieving removal percentages of 91% and 99% for phenol and 2,4-dichlorophenol, respectively, under optimal conditions. The adsorption of phenol and 2,4-dichlorophenol followed pseudo-second-order kinetics and Langmuir isotherm models, and the thermodynamic parameters confirmed spontaneous and exothermic adsorption. The reusability study showed that the adsorbent can be reused in wastewater treatment applications.