Abstract:

Solar interfacial evaporation is an emerging and sustainable method for seawater desalination and wastewater purification, which has great potential to alleviate freshwater shortages. Attapulgite/agar composite aerogel (AACA) was prepared from attapulgite and agar by physical mixing, freeze-drying and crosslinking. AACA had hierarchical porous structure, excellent thermal insulation and super hydrophilicity. In order to improve the light absorption ability of the material, the photothermal conversion material PPy-AACA was prepared by polypyrrole (PPy) spraying on the surface of AACA and its average light absorption rate could reach 97.7% in the range of 250—2500nm. Using PPy-AACA as a solar interfacial evaporator under the illumination intensity of 1 sun (1kW/m²), the evaporation rate of PPy-AACA was 1.5012kg/(m²·h), the energy conversion efficiency was 88.76%. PPy-AACA showed excellent stability and salt resistance in cyclic evaporation and brine evaporation experiments. In addition, the photothermal conversion material had also demonstrated the ability of seawater desalination and purification of dye wastewater, and the retention rate of salt ions and organic dyes was greater than 99%.

Key words: attapulgite, agar, aerogel, solar interfacial evaporation, seawater desalination

摘要：

太阳能界面蒸发是一种新兴的、可持续海水淡化和废水净化方法，在缓解淡水资源短缺方面具有巨大的潜力。本研究以凹凸棒和琼脂为原料，通过物理混合、冷冻干燥、交联反应等步骤制备得到凹凸棒/琼脂复合气凝胶（AACA），AACA具有分级多孔结构、优异的隔热性能以及超亲水性能。为了提高材料的光吸收性能，对AACA的表面进行聚吡咯（PPy）喷涂，制备得到了光热转换材料PPy-AACA，其在250~2500nm范围内的平均光吸收率可达到97.7%。以PPy-AACA作为太阳能界面蒸发器，在1个太阳的光照强度下（1kW/m²），PPy-AACA的蒸发速率为1.5012kg/(m²·h)，能量转换效率为88.76%。PPy-AACA在循环蒸发实验和盐水蒸发实验中表现出优异的稳定性和抗盐性能。此外，该光热转换材料还证明了海水淡化和净化染料污水的能力，其盐离子和有机染料的截留率均大于99%。

关键词: 凹凸棒, 琼脂, 气凝胶, 太阳能界面蒸发, 海水淡化