Biomass-derived Aerogels Research Articles

Eco-friendly MXene/enteromorpha prolifera biomass aerogel with excellent photothermal conversion and flame retardant properties for efficient separation of viscous oil/seawater mixture

Traditional adsorbents are often ineffective in cleaning up high-viscosity oil spills that cause harm to the marine environment. An efficient, safe and eco-friendly solution is urgently needed. Here, we prepare a superhydrophobic MXene/gelatin-enteromorpha prolifera biomass aerogel (H-MXene/G-EP) with excellent photothermal conversion and flame retardancy for solar-driven remediation of high-viscosity oil spills. The short-range aligned multidomain lamellar structure constructed through unidirectional freeze casting endows H-MXene/G-EP with compressibility and an adsorption capacity (63.7 g/g). Due to the excellent light responsiveness and full-spectrum high absorption of H-MXene/G-EP, it can reach a surface temperature 71.6 °C under 1 Sun (1.0 kW/m2), and an in-situ adsorption rate 367.40 g/h for viscous crude oil. The efficiency of separating O/W emulsions is up to 99.1%, which greatly broadens the range of applications for oil/water separation technology. Furthermore, the H-MXene/G-EP exhibits excellent flame retardancy, reducing the heat release rate by 89.59% and the total smoke production rate by 47.83%, respectively. This effectively reduces the probability of secondary marine fires. Thus, this novel biomass-derived aerogel provides a feasible and environmentally friendly solution for effective remediation of marine oil spills.

Wood-inspired elastic and conductive cellulose aerogel with anisotropic tubular and multilayered structure for wearable pressure sensors and supercapacitors

Cellulose nanofiber (CNF) aerogels hold considerable potential in wearable devices as pressure sensors and flexible electrochemical energy storage. However, the undirectional assembly of CNFs results in poor mechanical performance, which limits their application in structural engineering. In this study, we propose an anisotropic aerogel with both elastic and conductive properties inspired by the micro-nanostructure of natural wood. One-dimensional TEMPO cellulose nanofibers (TOCNF) were utilized as structural building blocks, while two-dimensional reduced graphene oxide (rGO) served as the electron transfer platform, owing to their high mechanical strength. The directionally aligned tubular structure composed of multilayered sheets was formed through rapid unidirectional freezing and subsequent steam heating reduction. These structures efficiently transferred stress throughout the porous skeleton, resulting in TOCNF-rGO aerogels with high compressibility and excellent fatigue resistance (2000 cycles at 60 % strain). The aerogel also exhibited high sensitivity, wide detection range, relatively fast response, and excellent compression cycle stability, making it suitable for accurately detecting various human biological and motion signals. Additionally, TOCNF-rGO can be assembled into a flexible all-solid-state symmetric supercapacitor that delivers excellent electrochemical performance. It is expected that this biomass-derived aerogel will be a versatile material for flexible electronic devices for energy conversion and storage.

Fe3O4-Functionalized κ-Carrageenan/Melanin Hybrid Aerogel-Supported Form-Stable Phase-Change Composites with Excellent Solar/Magnetic–Thermal Conversion Efficiency and Enhanced Thermal Conductivity

Impregnating organic phase-change materials (PCMs) into biomass-derived aerogels is regarded as one of the most effective and accessible approach to address the liquid leakage issues of solid–liquid PCMs. However, the inefficient solar–thermal conversion and low thermal conductivity still restrict the large-scaled applications of organic PCMs in solar utilization fields. Herein, novel form-stable PCM composites (CMPCM-Fe) with enhanced thermal conductivity and excellent solar- and magnetic-driven thermal energy conversion and storage efficiency were fabricated by impregnating n-docosane into Fe3O4-functionalized κ-carrageenan/melanin hybrid aerogels (CMA-Fe) through vacuum impregnation. CMA-Fe effectively supported n-docosane and prevented the leakage issue during the phase transition process owing to its strong surface tension and capillary force. CMPCM-Fe exhibited high encapsulated efficiency (88.9–94.6%), satisfactory thermal storage capacity (229.1–246.9 J/g), and excellent reversible stability. The introduction of Fe3O4 nanoparticles enhanced the thermal conductivity (55.3% increased) and solar–thermal conversion efficiency (up to 93.5%) of CMPCM-Fe and endowed it with excellent magnetic–thermal conversion capacity under an alternating magnetic field. The synthesized CMPCM-Fe possesses broad application prospect in mutiresponse thermal management.

Fully biomass-based aerogels with ultrahigh mechanical modulus, enhanced flame retardancy, and great thermal insulation applications

Biomass-derived aerogels have received extensive attention as potential thermal management materials for energy-efficient buildings. However, it remains a huge challenge to fabricate a fully bio-based aerogel with excellent mechanical property, flame retardancy, and low thermal conductivity. Herein, we demonstrate a novel and facile strategy to manufacture a fully biomass-based aerogel from naturally abundant ammonium alginate (AL) and phytic acid (PA), in which PA acting as both flame retardant and cross-linking components constructs a strong network with AL matrix. Consequently, the resultant biomass aerogel with a low density of 0.052 g/cm 3 exhibits ultrahigh mechanical modulus (25.1 ± 3.1 MPa) and specific modulus (440.4 ± 54.4 MPa cm 3 ·g −1 ), much superior to those of biomass aerogels ever reported. Due to the existence of the uniform three-dimensional porous network, the biomass aerogels exhibit low thermal conductivity (34–38 mW/m·K) and excellent thermal insulation performances. Further, the introduction of PA endows the aerogel with high flame retardancy (limiting oxygen index value of 57%, UL-94 V-0 rating, and extremely low heat release), while the biodegradability of the materials keeps at a high level with a biodegradation rate of 91.43%. Combining with the advantages of mechanically strong property, high flame retardancy, excellent thermal insulation, and biodegradation, the aerogel of this work provides a new strategy to fabricate thermal insulation materials with high environmental safety.