Ultrasonic-Assisted Rapid Preparation of Sulfonated Polyether Ether Ketone (PEEK) and Its Testing in Adsorption of Cationic Species from Aqueous Solutions

• Published in: Materials Vol. 15; no. 21; p. 7558
• Main Authors: Baltag, Laurentiu, Cojocaru, Corneliu, Enache, Andra-Cristina, Samoila, Petrisor, Harabagiu, Valeria
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 27.10.2022; MDPI
• Subjects: Adsorbents; Adsorption; Aqueous solutions; Cations; Chemical elements; Design optimization; Fuel cells; Membranes; Methylene Blue; modeling and optimization; Molecular docking; Morphology; NMR; Normal distribution; Nuclear magnetic resonance; Pollutants; Polyether ether ketones; Polymers; Pore size; Pore size distribution; Reaction time; Scanning electron microscopy; Spectrum analysis; sulfonated polyether ether ketone; Germany
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15217558

Herein, we report a new approach for the sulfonation of polyether ether ketone (PEEK) following a shorter path of reaction undertaken at 60 °C under ultrasonication. The application of this method enabled the reduction of the reaction time from several hours to less than one hour, achieving a relevant sulfonation degree. The sulfonated-PEEK (SPEEK) was characterized by advanced chemical and physical instrumental methods. According to 1H-NMR analysis, the degree of sulfonation of the polymer was equal to 70.3%. Advanced microscopy (SEM) showed that the fabricated SPEEK beads (2–4 mm) were porous inside with a log-normal distribution of pore sizes within the range 1.13–151.44 μm. As an application, the SPEEK polymer was tested for the adsorption of a cationic organic pollutant (Methylene blue, MB) from aqueous solutions. The equilibrium studies (isotherms) disclosed maximum adsorption capacities of 217 mg/g, 119 mg/g, and 68 mg/g at temperatures of 323 K, 313 K, and 300 K, respectively. The thermodynamic calculations indicated an endothermic effect (ΔHad = +11.81 kJ/mol) of the investigated adsorption process. The maximum removal efficiency of 99.14% was established by process optimization using the design of experiments strategy and data-driven modeling. Additionally, molecular docking simulations were performed to disclose the mechanism of interaction at the molecular level between the adsorbent (SPEEK) and pollutant.