Photothermal Aerogel Beads Based on Polysaccharides: Controlled Fabrication and Hybrid Applications in Solar-Powered Interfacial Evaporation, Water Remediation, and Soil Enrichment

Abstract

Solar-powered interfacial evaporation has emerged as an innovative and sustainable technology for clean water production. However, the rapid, mass and shape-controlled fabrication of three-dimensional (3D) steam generators (SGs) for versatile hybrid applications remains challenging. Herein, composite aerogel beads with self-contained properties (i.e., hydrophilic, porous, photothermal, and durable) are developed and demonstrated for threefold hybrid applications including efficient solar-powered interfacial evaporation, water remediation, and controlled soil enrichment. The rational incorporation of selected polysaccharides enables us to fabricate bead-like aerogels with rapid gelation, continuous processing, and enhanced ion adsorption. The composite beads can attain a high water evaporation rate of 1.62 kg m–2 h–1 under 1 sun. Meanwhile, high phosphate adsorption capacity of over 120 mg g–1 is achieved in broad pH (2.5–12.4) and concentration (200–1000 mg L–1) ranges of phosphate solutions. Gratifyingly, we demonstrate the first example of recycling biomaterials from interfacial SGs for controlled nutrient release, soil enrichment, and sustainable agriculture. The phosphate-saturated beads can be gradually broken down in the soil. Macronutrients (N, P, and K) can be slowly released in 50 days, sustaining the plant germination and growth in a whole growth stage. This work shines light on the mass and controlled fabrication of aerogel beads based on double-network biopolymers, not merely scaling up solar-powered interfacial evaporation but also considering water remediation, waste material disposal, and value-added conversion.

Enhancing Solar-Driven Water Purification by Multiscale Biomimetic Evaporators Featuring Lamellar MoS2/GO Heterojunctions

“…(b) ER under different solar intensities. (c) Comparisons of our current work with other recently reported works under 1 sum illunination. − ,− ,− ,− (d) Biomimetic evaporator device working under the natural sun. (e) ER at different times during the day.…”

“…However, the present desalination methods, involving distillation and reverse osmosis, exhibit not only high energy consumption but also low efficiency. − Solar desalination can provide a sustainable supply of low-cost, clean drinking water for communities. For a highly efficient evaporator driven by solar energy, the following aspects are necessary to be appraised: , (1) prominent photothermal conversion performance, , (2) an optimal structure to focus photothermal energy at the water–air interface, (3) excellent salt scaling resistance, , and (4) an appropriate steam collection system. , Although some highly efficient evaporators have been developed, − the water evaporation rate (ER) is theoretically limited to 1.47 kg m –2 h –1 at a given solar intensity, which urgently requires the discovery of more effective photothermal conversion materials to exceed this limit.…”

Self‐Contained Moisture Management and Evaporative Cooling Through 1D to 3D Hygroscopic All‐Polymer Composites

“…Solar-powered dehydration was conducted using an artificial optical setup (≈27 °C and ≈30% RH) under a broad solar intensity range of 0.6−1 sun. [71][72] The water-saturated fabrics (size: 10 × 30 mm 2 , thickness: 0.5 mm) were placed on a Petri dish (diameter: 6.5 cm) and illuminated under the solar simulator. The surface temperatures of all samples were measured via an infrared (IR) camera.…”

A wood-inspired bimodal solar-driven evaporator for highly efficient and durable purification of high-salinity wastewater

“…4,5 Solar-driven interfacial evaporation has attracted widespread attention because it is an environmentally friendly and sustainable technology, which utilizes sufficient solar energy to vaporize unpuried water. [6][7][8] Instead of evaporating the overall bulk water, the core of the current solar evaporation system is to separate the evaporation interface from the bulk water and achieve efficient steam generation through effective thermal positioning and energy connement. 9,10 However, the reported solar evaporators are generally effective for pure water harvesting by purifying lowsalinity brine, which is difficult to meet the salt resistance requirements for treating high-salinity wastewater (>15 wt%).…”