Polyethylenimine-Modified Membranes for CO₂ Capture and in Situ Hydrogenation

Abstract

Enzymatic CO reduction can provide value-added chemicals from greenhouse gases at ambient temperature and pressure. However, poor solubility of CO results in a low conversion rate. In this work, polyethylenimine (PEI) was attached onto the surface of poly(acrylic acid)-grafted (PAA-grafted) polyethylene membranes, and then, the membranes were used in an integrated process of CO capture and in situ hydrogenation. Modification conditions were optimized with a surface amino group density of PEI-modified membranes as the characteristic parameter, and then, SEM, FTIR, and XPS analyses were conducted. The effect of PEI-modified membranes on enzyme-catalyzed CO conversion to formic acid, regeneration conditions, and reusability were studied. The results show that when the grafting ratio of PAA increased, surface amino group density of PEI-modified membranes increased up to 6.00 × 10 mol/cm and then kept constant. The optimum modification time, temperature, and PEI concentration were 40 min, 40 °C, and 0.3 wt %. With the same concentration, PEI-1800 could bring more amino groups than PEI-600. SEM, FTIR, and XPS results further confirmed PEI attachment. Introduction of membrane-supported PEI with 5.86 × 10 mol of amino groups facilitated greatly enzymatic CO hydrogenation, and the initial reaction rate increased from 0.280 to 6.90 μM/min. After being regenerated in ammonia, PEI-modified membranes could be reused, and the relative reaction rate was, respectively, 88.0% and 65.7% after 5 and 10 cycles.

Development of an Ionic Porphyrin-Based Platform as a Biomimetic Light-Harvesting Agent for High-Performance Photoenzymatic Synthesis of Methanol from CO2

“…According to Wang et al, the reaction rate of enzymatic conversion of CO 2 was increased from 0.280 to 6.90 μM by grafting PEI on the support for capture CO 2 . 44 Also, Jiang et al reported that methanol concentration was increased by increasing local CO 2 concentration, which was ascribed to the switching of the equilibrium to the product side. 45 PDA/PEI contributed therefore to improve methanol concentration by increasing local CO 2 concentration.…”

“…Furthermore, local CO 2 concentration around enzymes was enhanced by PDA/PEI coating, owing to a large amount of amino groups on PDA/PEI that could capture CO 2 . According to Wang et al., the reaction rate of enzymatic conversion of CO 2 was increased from 0.280 to 6.90 μM by grafting PEI on the support for capture CO 2 . Also, Jiang et al reported that methanol concentration was increased by increasing local CO 2 concentration, which was ascribed to the switching of the equilibrium to the product side .…”

Dopamine/Polyethylenimine-Modified Silica for Enzyme Immobilization and Strengthening of Enzymatic CO2 Conversion

“…In our previous work, polyethyleneimine (PEI) with high affinity to CO 2 was introduced to the surface of the carboxyl-functionalized polymer membrane that was then applied in an integrated process of CO 2 capture and in situ enzymatic hydrogenation, and the initial reaction rate was increased by 24.6 times, much higher than all reported. This finding proves that the PEI-modified material may be a promising candidate for process intensification of the enzymatic conversion of CO 2 .…”

“…Unless specified otherwise, all enzymatic reactions were carried out at 37 °C and 170 rpm in 0.05 M PB (pH 6.0), and in a sealed stainless-steel reactor. 24 Typically, PDA/ PEI-SiO 2 was added to the reaction solution (2 mL) containing 50 mM NADH and 2 mg of FDH. After being purged with CO 2 , the reactor was sealed and kept at 0.5 MPa.…”

Synthesis and Characterization of Aminosilane Grafted Cellulose Nanocrystal Modified Formaldehyde-Free Decorative Paper and its CO2 Adsorption Capacity

“…At present, a series of solid adsorbents mainly include zeolite, activated carbon, hydrotalcite, metal oxides, and solid amine adsorbents [8][9][10][11][12]. Amino-modified adsorbents have high selective adsorption capacity (they adsorb CO 2 in the air instead of N 2 ) and higher CO 2 adsorption capacity [13,14]. Meanwhile, amine-modified adsorbents can be divided into impregnation and grafting methods according to their different synthesis methods.…”