Min Yin,Chaohu Xiao,Yang Jin,Yanyu He,Yuhan Zhang,Lihua Chen
Solar-driven interfacial evaporation plays an essential part in the production of potable water. Nevertheless, the intricate water conditions in real-world scenarios continue to pose limitations on its utilization. This study prepared a novel bionic PPy/BiVO 4 -PI/MXene aerogel composite material with radial center structure through directional freezing as the evaporator, which integrates both photothermal and photocatalytic properties into the evaporation system. In order to evaluate the efficacy of photocatalytic degradation and salt collection during interfacial evaporation, high-concentration saline water, simulated seawater and dyeing wastewater were employed as substitutes for real contaminated water bodies. After being exposed to 1 kW/m −2 (−|-) of irradiation, the PPy/BiVO 4 -PI/MXene composite exhibits an evaporation rate of 1.64 kg m -2 h −1 and achieves a photothermal efficiency of 96.77 %. In high-concentration saltwater containing 20 wt% NaCl, the PPy/BiVO 4 -PI/MXene exhibited an evaporation rate of 1.32 kg m -2 h −1 and a photothermal conversion efficiency of 77.41 %. Furthermore, approximately 26.7 g of salt can be collected after 15 days’ continuous evaporation. Furthermore, the PPy/BiVO 4 -PI/MXene demonstrated exceptional photocatalytic capabilities to organic dyes such as MB, RhB, CR and MG with removal efficiencies of 79.28 %, 70.96 %, 76.70 % and 80.95 %, respectively. This study realizes the synergistic effect of interfacial evaporation, photocatalysis and salt collection, providing a highly promising choice for the treatment of high-salt dyeing wastewaters.
Muneerah Alomar,Badriah S. Almutairi,Seham S. Alterary,Manal A. Awad,Fida Hussain,Awatif A. Hendi,Maha F. El-Tohamy,N. Al-Hoshani
Water scarcity is a serious issue which is increasing gradually due to rapid industrialization and population explosion. Biomass-inspired photothermal materials are of great importance due to their low-cost and enhanced photothermal conversion efficiencies. Herein, a pyrolyzed honokiol biochar (HB) is successfully synthesized to fabricate a self-regenerating solar evaporating system for in situ freshwater, and salt collection from seawater. The pyrolyzed biochar was innovatively printed onto a non-woven fabric (HB@NF) that exhibits excellent solar absorption (96%), and efficient stability in seawater. The self-regenerating structure is constructed in two parts: (1) HB-printed fabric as a photothermal layer for efficient solar-to-vapor conversion efficiencies (93%) under 1 kW m−2. (2) Umbrella-like centralized seawater supply via cigarette filter to achieve the Marangoni effect for in situ water evaporation and salt collection. More importantly, effective thermal management achieved efficient heat accumulation (48.5 °C) under one sun intensity (1 kWm−2), and its validation is also demonstrated in a COMSOL heat transfer simulation. Furthermore, a series of experiments on salt collection over different periods, evaporation stability under different cycles, and rejection of primary metal ions via Inductively Coupled Plasma–Optical Emission Spectrometry (ICP–OES) have been investigated. It is believed that this work will create new avenues regarding in situ freshwater and minerals recovery from seawater.Keywords:water scarcity;solar evaporation;honokiol;self-regeneration;freshwater;salt collection
Solar photothermal interfacial evaporation represents an approach for water purification and desalination, offering a solution to mitigate global water scarcity. However, the uncontrolled crystallization of NaCl on the evaporator surface during saline water evaporation can reduce evaporation efficiency, block water channels, and degrade the evaporator. In this study, we designed an evaporator that effectively suppresses the crystallization of NaCl (200), thereby regulating the crystal structure and shape of the precipitated NaCl. Besides, a Janus hemispherical evaporation interface was proposed, facilitating the self-shedding of NaCl under gravity. The collecting resistance ( F Cr ) of dendritic NaCl is reduced by about two orders of magnitude than that of cubic NaCl. Under 1 kW m −2 illumination, the evaporator simultaneously achieved a high NaCl salt collection efficiency of 54.30 % and the evaporation rate of 1.10 kg m −2 h −1 when treating 20 wt% saltwater. This work introduces a strategy for salt resource extraction and pure water production.
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