Sustainable Biochar-Based Solar Absorbers for High-Performance Solar-Driven Steam Generation and Water Purification

Abstract

Solar-driven interfacial steam generation is emerging as a green and sustainable technology for potential applications in sterilization, desalination, and water purification. Despite the encouraging progress to date, the solar absorbers of the interfacial steam generators generally are composed of costly and/or delicate nanostructures made from metal particles or semiconductor materials, which partially hinder their mass production for practical applications. Herein, the biomass Enteromorpha prolifera was successfully recycled to construct four biochar-based solar absorbers via a set of processing methods. The hydrophilic, hierarchically porous, and microtubular nanostructures of the carbonized E. prolifera contribute to synergistically efficient water pumping and steam generation of the solar absorbers. Inspired by the natural transpiration of trees, the two-dimensional interfacial steam generators based on the four solar absorbers attain good water evaporation rates of 1.1− 1.3 kg m −2 h −1 and high photothermal conversion efficiencies of 80−84% under one sun. Specifically, the performance is among the best-performing solar steam generators constructed via biochar-based solar absorbers. The indoor and outdoor experiments demonstrate the first example of using green tide as a sustainable source for biochar-based solar absorbers and realizing costefficient and high-performance steam generation and clean water production.

Low-cost and scalable carbon bread used as an efficient solar steam generator with high performance for water desalination and purification

“…[11][12][13][14] To this end, immense efforts have been dedicated to developing an advanced absorber to achieve the above properties. [13][14][15][16][17][18][19][20][21][22][23][24][25][26] So far, multitudinous materials including plasmonic metals, 13,[15][16][17][18] carbon-based nanostructures, 14,[19][20][21][27][28][29] semiconductors 22,23 and bio-inspired materials [24][25][26][30][31][32] have been investigated by researchers to boost the efficiency of solar energy harvesting further. For instance, Zhu's group 18 demonstrated a gold based plasmonic absorber, which has over 90% efficiency under 4 sun (4 kW m À2 ) illumination.…”

Biowaste‐Derived Carbonized Bone for Solar Steam Generation and Seawater Desalination

“…In fact, after the desalination experiment the ions concentration of Na + , Mg 2+ , K + , Ca 2+ , and Sr + in the collected water are 8.70, 0.90, 0.75, 0.45, and 0 mg L −1 , respectively, lower than the values set by WHO (World Health Organization) for the drinking water such as (100, 50, 10, and 3 mg L −1 ). [56,57] These values not only meet the WHO drinking water standards but also are lower than that of the water recovered after treatment using the current state-of-the-art thermal distillation (1-50 mg L −1 ) and membrane-based seawater desalination processes (10-500 mg L −1 ). [58]…”

Highly Efficient Solar Steam Generation under Low Solar Flux via Carbon‐Nanotube‐Modified Sugarcane

“…The solar energy conversion efficiency of CNT-SC under 1 sun is 94.2%, which is higher than most recently reported biomass-based solar evaporators and is the highest efficiency among the sugarcane-based materials (Figure 4c and Table S1). [22,25,31,32,35,[42][43][44][45][46] With the increase of solar illumination up to 5 sun, visible steam can be observed on the CNT-SC surface with the efficiency of 95.8%, demonstrating the fast evaporation of water.…”

“…[8][9][10] The solar-thermal material plays a crucial role and an optimal absorber should satisfy several characteristics: 1) strong and broadband light absorption; 2) excellent thermal management to minimize the heat loss; and 3) porous structure for water transport. [11,12] Various light absorbers such as carbon foam, [13,14] graphene, [15,16] carbon nanotubes (CNTs), [17,18] metal nanomaterials, [19,20] biomass-based materials, [21][22][23][24][25] and other materials [26] have been used as light-to-heat conversion materials for efficient solar steam evaporation. Although great efforts have been made, the practical applications of most absorbers are relatively limited due to the high cost, complicated fabrication, or poor efficiency under low solar flux.…”