Adsorption and Recognition Property of Tyrosine Molecularly Imprinted Polymer Prepared via Electron Beam Irradiation

Abstract

To realize the selective separation of L-tyrosine (L-Tyr) and avoid the drawbacks of traditional thermal polymerization, electron beam irradiation polymerization was developed for the fabrication of L-Tyr molecularly imprinted polymers (MIPs). Firstly, L-Tyr MIPs were prepared with methacrylic acid and ethylene glycol dimethacrylate and without an initiator. Then, the influence of absorbed dosage and temperature on the adsorption capacity of L-Tyr, as well as the thermodynamic behavior, were investigated. The maximum adsorption capacity of 10.96 mg/g for MIPs was obtained with an irradiation dosage of 340 kGy under 15 °C, and the ΔH0 and ΔS0 of the adsorption process are −99.79 kJ/mol and −0.31 kJ/mol·K, respectively. In addition, the effect of adsorption time on adsorption performance was evaluated under different initial concentrations, and the kinetic behavior was fitted with four different models. Finally, the recognition property of the obtained MIPs was investigated with L-Tyr and two analogues. The obtained MIPs have an imprinting factor of 5.1 and relatively high selective coefficients of 3.9 and 3.5 against L-tryptophan and L-phenylalanine, respectively. This work not only provided an L-Tyr MIP with high adsorption capacity and selectivity but also provided an effective and clean method for the synthesis of MIPs.

Adsorption of Levofloxacin onto Graphene Oxide/Chitosan Composite Aerogel Microspheres

“…In addition, the ∆H 0 and ∆S 0 were −2.21 kJ/mol and −5.8 J/mol•K, respectively. The negative value of ∆H 0 shows that LOF adsorption is exothermic, in agreement with other data, and the positive value of ∆S 0 shows that GO/CS aerogel microspheres have good affinity for LOF [26,37].…”

“…As shown in Table 1, with the increase in temperature, the ∆G 0 increased from −0.51 to −0.33 kJ/mol, revealing that the adsorption process is spontaneous. This result also indicated that low temperatures are beneficial for the adsorption of LOF, a finding that is consistent with the results for the effect of temperature on adsorption [37,38]. In addition, the ∆H 0 and ∆S 0 were −2.21 kJ/mol and −5.8 J/mol•K, respectively.…”

“…As can be clearly seen from the figure, the adsorption capacity decreased as the temperature increased, and the maximum capacity was observed at 25 °C. This result demonstrates that the adsorption process is exothermic [37,38]. Although low temperatures can increase adsorption capacity, upon considering the energy consumption needed for lower-temperature investigations and the accessibility of equipment, further investigations were conducted at 25 °C.…”

“…Thermodynamic investigations are very important in elucidating LOF adsorption, as the data produced can reveal whether the adsorption process is endothermic or exothermic and whether it is spontaneous. The thermodynamic parameters Gibbs free energy change (ΔG 0 ), enthalpy change (ΔH 0 ), and entropy change (ΔS 0 ) were calculated using Equations ( 1)-(3) [26,37]: Thermodynamic investigations are very important in elucidating LOF adsorption, as the data produced can reveal whether the adsorption process is endothermic or exothermic and whether it is spontaneous. The thermodynamic parameters Gibbs free energy change (∆G 0 ), enthalpy change (∆H 0 ), and entropy change (∆S 0 ) were calculated using Equations ( 1)-(3) [26,37]:…”

Optimization Conditions of Malachite Green Adsorption onto Almond Shell Carbon Waste Using Process Design

“…Moreover, Figure 4 c displays that the system is very close to the equilibrium within 5 min. Therefore, according to the study by Simonin, caution should be exercised when comparing PFO kinetics with PSO kinetics [ 55 ]. Because for the PFO model, when q t approaches q e , the value of (q e – q t ) becomes smaller and smaller, leading to the accuracy reduction of k1.…”