The construction of bio-inspired hierarchically porous graphene aerogel for efficiently organic pollutants absorption

Multi-scale microstructural construction in ultralight graphene aerogels enables super elasticity and unprecedented durability for impact protection materials

Ultralight graphene aerogels have gained extensive recognition in the impact protection field. However, attaining both elasticity and durability at low material density is challenging due to their intrinsic conflicts. Inspired by the mantis ootheca, we present a simultaneous improvement in the elasticity, durability, and density restrictions of ultralight graphene aerogels via constructing a multiscale honeycomb microstructure (MHM) within the graphene skeleton. This approach enables resulting graphene aerogel to achieve a strength per unit volume of 284.6 cm3 mg-1, the ability to recover its shape within 10 ms after an impact at 3.569 m/s, and maintain 97.2 % of its sample height after 20,000 cycles at 90 % strain. The operand analyses and calculation results reveal that the MHM structure facilitates this aerogel's dual-stage stress transfer pathway. Initially, the macroscale honeycomb structure (millimeter-scale) of the graphene aerogels bear and transmit stress to the surrounding regions, followed by the microscale honeycomb structure (micron-scale) deformation to convert stress kinetic energy into elastic potential energy. This two-stage stress transition mechanism of the MHM structure can effectively mitigate excessive local stress and suppress strain localization, thus providing remarkable elasticity and durability. Ultimately, the obtained graphene aerogel demonstrates promising applications as a fall height detection device and impact protective material.

High-efficiency and sustainable sodium humate aerogel evaporator for solar steam generation

The utilization of solar interface evaporation technology (SIET) for freshwater production from seawater and sewage is a sustainable, green, viable, and promising approach. However, the absorption rate of sunlight, evaporation rates, and high costs still pose large-scale solar steam generation. In this paper, a novel aerogel (named SAS) was prepared by graft copolymerization with sodium alginate (SA), acrylic acid (AA) and sodium humate (SH) in aqueous solution, using N, N'-Methylenebisacrylamide (MBA) as crosslinker and ammonium persulfate (APS) as initiator, which has high light absorption (90 %), high porosity (87.96 %), superhydrophilicity (35 ms), low thermal conductivity (0.23 W m-1 k-1). The evaporation rate of SAS aerogel can reach up to 1.66 kg m-2h-1 under 1 kW m-2 light intensity, and the reusability and reliability of SAS aerogel are verified by 10 cycles of experiments. The utilization of this SAS aerogel holds significant implications for the design and fabrication of cost-effective, high-performance solar steam evaporation systems, thereby offering promising solutions to address global freshwater shortages and enhance wastewater treatment efficiency.

Hierarchical Porous Aerogels With Multiple Adsorptive Interactions for Dye Wastewater Purification

Aerogels present a huge potential for removing organic dyes from printing and dyeing wastewater (PDW). However, the preparation of aerogels with multiple dye adsorption capabilities remains a challenge, as many existing aerogels are limited to adsorbing only a single type of dye. Herein, a composite aerogel (CG/T-rGO) with the addition of carboxymethyl chitosan, gelatin and tannic acid reduced graphene oxide (T-rGO) was synthesized by freeze-drying technology. The electrostatic interactions between dye molecular and GEL/CMCS (CG) networks, as well as the supramolecular interactions (H-bonds, electrostatic interactions and π-π stacks) between T-rGO, have endowed the aerogel with the ability to adsorb multiple types of dye, such as methylene blue (MB) and methyl orange (MO). Results exhibited that the prepared CG/T-rGO aerogel possessed strong mechanical strength and a porous 3D network structure with a porosity of 96.33 %. Using MB and MO as adsorbates, the adsorption capacity (88.2 mg/g and 66.6 mg/g, respectively) and the mechanism of the CG/T-rGO aerogel were investigated. The adsorption processes of aerogel for MB and MO were shown to follow the pseudo-second-order kinetic model and Langmuir isotherm model, indicating the chemical adsorption of a monolayer. The proposed aerogel in this work has promising prospects for dye removal from PDW.