Intensifying Solar Interfacial Heat Accumulation for Clean Water Generation Excluding Heavy Metal Ions and Oil Emulsions

Abstract

Solar‐driven interfacial steam generation has emerged as an innovative technique for seawater desalination due to its high photothermal conversion efficiency and potential industrial applications. Herein, a superior interfacial heat accumulation structure composed of semiconductive in situ polymerization (polypyrrole) of nickel foam (IPNF) is reported. The IPNF photothermal layer is assembled with superhydrophilic polyurethane substrate for synchronous water transport and excellent thermal insulation. The 2D ultrablack mesh induces multiple incident rays within the diffused polymerized surface, which allows omnidirectional solar absorption (88.5 %) and intensifying heat localization (49.5 °C @ 1 sun). The state‐of‐the‐art evaporation performances reveal that the integrated IPNF solar evaporator exhibits an excellent evaporation rate (1.74 kg m−2 h−1) and solar‐to‐vapor conversion efficiency (90% excluding heat losses) under 1 kW m−2 solar intensity. Besides this, the long‐term evaporation experiments show negligible discrepancy under seawater conditions (13.27 kg m−2/8 h under 1 kW m−2) and engrain its functioning potential for multimedia and salt rejection (3.2 g × NaCl/240 min). More importantly, herein, insights into different water states in the polymeric network systems during solar‐driven evaporation are provided. This work shows a significant potential to generate freshwater excluding heavy metals and other oil emulsions for industrial applications.

In situ polymerized Fe2O3@PPy/chitosan hydrogels as a hydratable skeleton for solar‐driven evaporation

“…For this, the time‐dependent mass change was recorded by placing the devices over a weighing balance with 0.001‐g resolution and exposed under simulated one sun irradiation. After 1 h, the mass change for all systems was recorded and the obtained data is shown in Figure 5A, revealing that the maximum mass change achieved by an Fe 2 O 3 @PPy/chitosan steam generator was up to 1.80 kg m −2 that is comparatively much higher than bulk water and other steam generation devices reported previously 18,20 . The successive mass change for Fe 2 O 3 @PPy/chitosan hydrogel was also investigated under various solar intensities up to 3 kW m −2 , and the computed data is represented in Figure 5B.…”

“…Many solar steam generation systems suffer from insufficient water production, inefficient light absorption, poor thermal management that causes massive heat losses in non‐evaporative areas and thus lowers the efficiency of systems 14–17 . Besides this, the synthesizing of self‐floating‐enabled noble material that potentially sustains the quick water supply to the localized heated area and holds long‐term stability without surface fouling under intense conditions has not been achieved successfully 18,19 . To tackle this dilemma, significant attempts are invested in the development of new potential functional materials, but still, its practical applications are limited due to significant barriers between the status quo and large‐scale applications 20,21 .…”

“…[14][15][16][17] Besides this, the synthesizing of self-floatingenabled noble material that potentially sustains the quick water supply to the localized heated area and holds longterm stability without surface fouling under intense conditions has not been achieved successfully. 18,19 To tackle this dilemma, significant attempts are invested in the develop-ment of new potential functional materials, but still, its practical applications are limited due to significant barriers between the status quo and large-scale applications. 20,21 Ceramic materials gained significant potential due to their thermal stability and anticorrosion nature.…”

Photothermal Diatomite/Carbon Nanotube Combined Aerogel for High‐Efficiency Solar Steam Generation and Wastewater Purification

“…[15][16][17][18][19][20][21][22] In addition to these photothermal materials, other materials such as ceramics and organic polymers are also widely used. [23][24][25] According to the position where the solar absorbing material is placed in the liquid medium, the photothermal system can be divided into three categories. The first system disperses light-absorbing materials in a working fluid, called nanofluids.…”

Solar‐Initiated Frontal Polymerization of Photothermic Hydrogels with High Swelling Properties for Efficient Water Evaporation

“…[6] Recently, many efforts have been devoted to rationalizing the design of material structures and evaporation systems to concentrate heat at the air/liquid interface, boosting evaporation efficiency to over 90%, even higher than 100%. [7][8][9][10][11][12][13] Among a variety of developed photothermal materials (e.g., semiconductors, [14,15] metallic, and carbonbased materials [16][17][18] ), hydrogel-based materials, as an emerging photothermic material possessing cross-linked interconnected three-dimensional (3D) networks, macroporous structure, and excellent hydrophilicity, have been extensively used to generate freshwater. [19][20][21][22][23] The porous structure of the hydrogels strengthens the internal light reflection and scattering, allowing enhanced light harvesting and absorption.…”