Ultralight, Mechanically Enhanced, and Thermally Improved Graphene-Cellulose-Polyethyleneimine Aerogels for the Adsorption of Anionic and Cationic Dyes

Abstract

Graphene-cellulose-polyethyleneimine aerogels (GA-MCC-PEI) were prepared using a simple, environmentally friendly method to remove anionic and cationic dyes in water. Graphene-cellulose hydrogels were prepared using a hydrothermal method and then immersed in a polyethyleneimine aqueous solution for 48 h to obtain graphene-cellulose-polyethyleneimine hydrogels, which were then freeze-dried. The light and porous composite aerogels had a good compression resistance, and the maximum allowable pressure of the graphene-cellulose-polyethyleneimine aerogel with a cellulose content of 43% was 21.76 kPa, which was 827 times its weight. Adsorption of the anionic dye amaranth and the cationic dye methylene blue by the graphene-cellulose-polyethyleneimine aerogel was satisfactorily modeled using the Langmuir isothermal equation, indicating monolayer adsorption. When the cellulose content was 39%, the equilibrium adsorption capacities of the composite aerogel for amaranth and methylene blue were 369.37 mg/g and 237.33 mg/g, respectively. This graphene-cellulose-polyethyleneimine aerogel can be used to remove dye pollutants in water to maintain ecological balance, thus broadening the application space of aerogel materials, that is, as adsorbents in different environments.

SiO2 Nanostructure-Based Aerogels with High Strength and Deformability for Thermal Insulation

“…Thereinto, the average pore sizes of H2F-SA-0.214, H2F-SA-0.252, and H2F-SA-0.334 are close to or lower than the average free path of air molecules (about 70 nm), which can effectively suppress the convective heat transfer. Usually, thermal conduction and thermal convection at room temperature are the main causes of thermal conductivity, and the thermal radiation is negligible. , For aerogel materials with high porosities, the thermal convection occupies a major part of the thermal conductivity. , Therefore, the thermal conductivities of H2F-SA-0.214, H2F-SA-0.252, and H2F-SA-0.334 are relatively low (Figure d). Although H2F-SA-0.334 has an lower average pore size, a higher density results in a higher solid-phase thermal conduction, resulting in a higher thermal conductivity than that of H2F-SA-0.252.…”

“…3,28 For aerogel materials with high porosities, the thermal convection occupies a major part of the thermal conductivity. 29,30 Therefore, the thermal conductivities of H2F-SA-0.214, H2F-SA-0.252, and H2F-SA-0.334 are relatively low (Figure 3d). Although H2F-SA-0.334 has an lower average pore size, a higher density results in a higher solid-phase thermal conduction, resulting in a higher thermal conductivity than that of H2F-SA-0.252.…”

A Novel Method for the Fabrication of Antibacterial Stainless Steel with Uniform Silver Dispersions by Silver Nanoparticle/Polyethyleneimine Composites

“…The highly cross-linked structure of the PEI-GA-Ag composite is also capable of generating more van der Waals forces with the 316LSS surface [ 50 ]. Furthermore, the negative zeta potential of the metal surface is a critical parameter for attracting the functional polymer, PEI-co-GA/Ag (a cationic polymer), with a positive charge [ 51 , 52 ]. In that case, the charged cationic amine groups in the PEI structure are able to form a tight attraction with the surface of 316LSS while achieving an effective distribution of Ag NPs through the branched structure of the PEI.…”

On the Analysis of Cryogels and Xerogels Using Cellulose Nanofibers and Graphene Oxide

“…A decrease in the peaks at around approximately 12° compared to the GO XRD was observed, indicating its reduction. Furthermore, the characteristic peak of NFC at around approximately 16° is defined in the nanomaterials [ 57 ].…”