The research paper titled "A novel slide-like cotton-based evaporator with gradient evaporation strategy for seawater resource acquirement" is authored by Master student Qian Liang as the first author and Associate Professor Changkun Liu as the corresponding author. The affiliations of both the first author and the corresponding author are Shenzhen University. This paper was published in Chemical Engineering Journal, which has an impact factor of 13.3 (at the accepted/publication date) and is listed as Tier 1 journal as categorized by the Chinese Academy of Sciences.

Solar-driven Interfacial Evaporation (SDIE) is a promising green technology with great potential for seawater desalination. In this study, a novel slide-like cotton-based solar evaporator is designed using Carbon Nanotubes (CNTs) and Musou Black (MB) in an inclined mode, achieving a fast capillary force-induced gravity-assisted water transport. The evaporator achieved a stable desalination of the concentrated brine (10.0 wt% NaCl solution) at the evaporation rate of 1.44 kg m^-2 h^-1 under one simulated sunlight (1 KW m^-2). Adequate water supply facilitated a superior self-cleaning property without salt aggregation at the evaporation surface and its periphery. In the 10-day long-term evaporation (3.5 wt% NaCl solution), a stable water evaporation rate (1.77 kg m^-2 h^-1) and a light-to-heat conversion efficiency (95.47%) were obtained without salt aggregation. The evaporation rate could even reach 1.88 kg m^-2 h^-1 in a closed evaporation system outdoors under the practical light. Then, the gradient evaporation strategy was applied by combination of the slide-like solar evaporators consecutively in three stages, in-between which two collection tanks for the concentrated seawater were present. As the concentrated seawater can be used to extract Li, Mg, etc., and the mineral salts of the sea can be used for nutrients, bathing products, etc., the gradient evaporation strategy has realized the simultaneous derivation of the condensed pure water, the concentrated seawater with different concentrations, and the mineral salts at the last stage as industrial raw materials. This study provides new insights into the design of high-efficiency solar evaporators that can comprehensively realize the utilization of seawater resources.

Full-text link: https://doi.org/10.1016/j.cej.2023.147222

The research paper titled "Novel mushroom-like cotton-based evaporator for simultaneous freshwater production and salt harvesting via edge-preferential crystallization" is authored by Master student Jun Li as the first author and Associate Professor Changkun Liu as the corresponding author. The affiliations of both the first author and the corresponding author are Shenzhen University. This paper was published in Chemical Engineering Journal, which has an impact factor of 13.3 (at the accepted/publication date) and is listed as Tier 1 journal as categorized by the Chinese Academy of Sciences.

Solar-driven interfacial evaporation (SDIE) has emerged as a promising technology to alleviate the global freshwater scarcity. However, the simultaneous collection of water and salt as resources while maintaining stable evaporation rate without salt contamination at the evaporation interface remains a huge challenge. Herein, we report a novel mushroom-like cotton-based evaporator, inspired by the vertical stem and inclined caps of mushrooms, for simultaneous freshwater production and salt harvesting. By depositing polyaniline (PANI) and carbon nanotubes (CNTs) onto the cotton fabric (CF), an evaporation rate of 1.88 kg m^-2 h^-1 and a high solar evaporation efficiency of 99.4% can be achieved in 3.5 wt% NaCl solution under one solar irradiation. Furthermore, a significant water collection efficiency of 70.2% and a high salt harvesting rate of 42.1 kg m^-2 h^-1 can be derived. Even exposed to high-concentration (15 wt%) brine, our design still effectively prevents salt contamination. The distinctive edge-preferential crystallization not only avoids the salt contamination but also promotes the salt harvesting, due to the capillary force, the criss-cross water channels from the nature of cotton cloth, as well as the gravity-assisted water transport of the “mushroom cap” during evaporation. In addition, the low thermal conductivity (0.163 W m^-1 K^-1) of the photothermal layer with the integration of PANI and CNTs, as well as the vertical water upward transport via the “mushroom stem” effectively reduce the heat loss. This research holds great potential for seawater desalination applications with the comprehensive utilization of seawater resources.

Full-text link: https://doi.org/10.1016/j.cej.2024.151670

The research paper titled "Novel solar evaporator with closely-stacked reverse U-shaped hydrogel tubes for long-term stable evaporation with excellent salt resistance" is authored by Master student Dahang Deng as the first author and Associate Professor Changkun Liu as the corresponding author. The affiliations of both the first author and the corresponding author are Shenzhen University. This paper was published in Chemical Engineering Journal, which has an impact factor of 15.1 (at the accepted/publication date) and is listed as Tier 1 journal as categorized by the Chinese Academy of Sciences.

The effective long-term utilization of the solar desalination technology requires stable evaporation rates and the ability to prevent salt crystallization. To address these challenges, this paper develops a novel 3D stacked hydrogel solar evaporator using reduced graphene oxide (rGO), sodium alginate (SA), and polyvinyl alcohol (PVA) to create hollow hydrogel tubes having multiple capillary structures. This evaporator with closely stacked reverse U-shaped hydrogel tubes has an average evaporation rate of 1.51 kg m^-2 h^-1 for pure water evaporation and a solar evaporation efficiency of 93.65%, due to the presence of hydrophilic groups and the unique 3D structure. The simulated experiment demonstrates that the evaporation rates of different locations on the surface of the three-dimensional evaporator are non-uniform. This is due to the joint impact of the water supply in the hydrogel tubes and the surrounded air humidity fields. The evaporator maintains a stable evaporation rate greater than 1.31 kg m^-2 h^-1 for 12 h of light per day and for seven consecutive days in simulated seawater, with no formation of crystalline salt. The experimental and finite element simulation results show that the salt con centration at the evaporation interface increases to 4.54 wt% after operating the evaporator in a 3.5 wt% NaCl solution for a certain period. Due to the effective water supply and structural characteristics, the highly concentrated brine at the top can flow back to the water body along the concentration gradient, which prevents the salt crystallization and ensures the stable operation of the evaporator. This study designs a stable and efficient 3D solar evaporator for seawater desalination, which supports the theoretical application for addressing freshwater scarcity.

Full-text link: https://doi.org/10.1016/j.cej.2023.145422

The research paper titled "Directional solution transfer of a 3D solar evaporator inhibiting salt crystallization" is authored by Master student Ye Peng as the first author and Associate Professor Changkun Liu as the corresponding author. The affiliations of both the first author and the corresponding author are Shenzhen University. This paper was published in Journal of Materials Chemistry A, which has an impact factor of 14.5 (at the accepted/publication date) and is listed as Tier 1 journal as categorized by the Chinese Academy of Sciences.

Solar interface evaporation with high thermal utilization and evaporation rate has great application potential for seawater desalination. Improving evaporation performance and inhibiting the formation of crystalline salt are the key to achieve long-term continuous and efficient solar desalination. In this study, a novel 3D hydrogel evaporator constructed from cotton, reduced graphene (rGO), sodium alginate (SA) and polyvinyl alcohol (PVA) was prepared by a simple method. The evaporator showed an excellent evaporation rate of 4.57 kg m⁻² h⁻¹ and kept high-performance evaporation without salt crystallization for 5 days. Based on the excellent water transport capacity and the exceptional 3D structure, the evaporator realized cold and heat dual-mode evaporation enhancing the evaporation performance and the suppression of salt crystallization by directional solution transfer. This work aimed to solve the shortage of freshwater resources by developing sustainable and high-performance solar desalination technology.

Full-text link: https://doi.org/10.1039/d1ta05529a

The research paper titled "Novel Three-Dimensional Cut Umbrella-like Evaporator with Four Angle-Adjustable Evaporation Surfaces in a Submersible Floatation State for Enhanced Seawater Desalination" is authored by Master student Dahang Deng as the first author and Associate Professor Changkun Liu as the corresponding author. The affiliations of both the first author and the corresponding author are Shenzhen University. This paper was published in ACS Sustainable Chemistry & Engineering, which has an impact factor of 7.1 (at the accepted/publication date) and is listed as Tier 1 journal as categorized by the Chinese Academy of Sciences.

Solar-driven evaporators provide eco-friendly and efficient solutions for purifying seawater. This study developed a novel three-dimensional (3D) cut umbrella-like evaporator (CUL-evaporator) featuring four angle-adjustable evaporating surfaces incorporating cross-linked poly(vinyl alcohol) (PVA) and reduced graphene oxide (rGO) into cotton fabric. Notably, the CUL-evaporator with less production material outperforms the full umbrella-like evaporator (FUL-evaporator) in terms of the evaporation rate and pure water production. This superior performance results from the effective utilization of the back sides of the evaporating surface for water evaporation. When positioned at a 22.5° angle, the CUL-evaporator achieved a high evaporation rate of 3.45 kg h^–1 m^–2, benefiting from the gravity-assisted water transport. Furthermore, it performed consistently over 7 days, maintaining an evaporation rate of 3.36 kg h^–1 m^–2 using simulated seawater (3.5 wt%). The CUL-evaporator also exhibited excellent stability, preventing salt accumulation on the evaporating surface, even with high-concentrated salty water (20 wt% NaCl). Leveraging these characteristics, an outdoor submersible floatation evaporator installation was designed and achieved substantial water production of 7.63 L m^–2 within 8 h. This study presented a novel design model for 3D evaporators, offering an effective approach for long-term, stable, and salt-resistant evaporation processes.

Full-text link: https://doi.org/10.1021/acssuschemeng.3c05529

The research paper titled "Overcoming salt crystallization with ionic hydrogel for accelerating solar evaporation" is authored by Associate Research Fellow Xinzhen Zhao as the first author and Associate Professor Changkun Liu as the corresponding author. The affiliations of both the first author and the corresponding author are Shenzhen University. This paper was published in Desalination, which has an impact factor of 9.5 (at the accepted/publication date) and is listed as Tier 1 journal as categorized by the Chinese Academy of Sciences.

A new hydrogel-based solar evaporator was prepared by a convenient one-step cross-linking method. Sodium alginate and PEDOT:PSS composite hydrogels were used as the functional layer to realize photothermal conversion and in situ heating for the generation of the solar steam. The evaporation rate of the evaporator was as high as 1.23 kg m^-2 h^-1, and the removal rate of various ions in simulated seawater was higher than 99.8%, showing excellent application stability. It was also found that the salt crystallization phenomenon could be effectively overcome in the process of solar desalination. Based on the swelling ability and super hydrophilic three dimensional pores of the ionic hydrogel, the evaporator exhibited stable self-driven water-drawing ability to form a hydration layer in an effort to suppress the supersaturation of the salt solution at the evaporation interface. PEDOT component realized in situ heating of the hydration layer near the evaporation interface for enhancing the utilization of thermal energy. The purpose of this paper is to provide references for the practical desalination application using a new hydrogel-based solar evaporator.

Full-text link: https://doi.org/10.1016/j.desal.2020.114385