Adsorption of l-phenylalanine on ordered mesoporous carbons prepared by hard template method

Highlight
• Mesoporous carbons CMK-3 and CMK-8 were prepared by hard template method.
• Adsorption of l-phenylalanine was studied from solutions with different pH.
• Electrostatic, hydrophobic, steric interactions are important in l-Phe adsorption.
• Sorption capacities decrease in the following order: CMK-8 > CMK-3 > KIT-6 > SBA-15.
• Adsorption of l-Phe leads to a decrease in surface area and pore volume of carbons.

Mesoporous carbons, CMK-3 and CMK-8 were synthesised by hard template method with the use of ordered silicas SBA-15, KIT-6 as solid state matrices and sucrose as carbon precursor. The physicochemical properties of materials obtained were characterised by X-ray diffraction, electron transmission microscopy and low-temperature nitrogen adsorption. The results proved the presence of ordered mesoporous structure both in CMK-3 and in CMK-8. Adsorption of l-phenylalanine by mesoporous adsorbents was studied from solutions of different pH 5.6–9.4. Electrostatic, hydrophobic and steric interactions are all likely to be important effects in amino acid adsorption. The maximum sorption capacity was observed at pH 5.6, close to the isoelectric point of l-phenylalanine (pI = 5.48). Above this pH value, the amount of adsorbed amino acid decreases. Mesoporous carbons CMK-8 and CMK-3 show much higher sorption capacities than silica. The adsorption capacities of different mesoporous adsorbents decrease in the following order: CMK-8 (2446 μmol/g) > CMK-3 (1654 μmol/g) > KIT-6 (420 μmol/g) > SBA-15 (389 μmol/g).