聚乙烯醇/海藻酸钠复合气凝胶的制备及其高效海水淡化应用

李萌; 王甜; 侯宪广; 张宪胜

聚乙烯醇/海藻酸钠复合气凝胶的制备及其高效海水淡化应用

青岛大学　纺织服装学院青岛 266071

基金项目: 国家自然科学基金 (No. 52003131)；

详细信息

通讯作者:
张宪胜，博士，副教授，硕士生导师，研究方向为功能防护与能量转换材料　E-mail: xshzhang@qdu.edu.cn

中图分类号: TB332
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- 被引次数: 0
出版历程
- 收稿日期: 2022-11-10
- 修回日期: 2023-02-15
- 录用日期: 2023-03-03
- 网络出版日期: 2023-03-14

Preparation of polyvinyl alcohol/sodium alginate composite aerogel and its application in efficient seawater desalination

College of Textiles and Clothing, Qingdao University, Qingdao 266071, China

Funds: National Natural Science Foundation of China (No. 52003131)

摘要

摘要: 太阳能是最大的可再生和可持续能源，基于太阳能界面水蒸发技术的海水淡化蒸发器可以实现海水的淡化提纯，吸引了越来越多研究者的关注。但目前海水淡化蒸发器的蒸发速率相对较低，严重限制了其实际应用。本文创新性地将碳纳米管(CNT)与聚乙烯醇(PVA)和海藻酸钠(SA)复合，通过定向冷冻方法制备了具有不同垂直孔隙的PVA-SA复合气凝胶，并将其组装成二维(2D)和三维(3D)的太阳能蒸发器。通过调整PVA和SA溶液的浓度，可以调控最终气凝胶的内部孔隙尺寸，实现高效的水传输和良好的热管理性能。通过系统研究PVA与SA的浓度、两者复合比例等因素对微观孔隙和蒸发速率的影响，制备的气凝胶蒸发器光吸收率可以达到97%左右，在一个太阳光照射下最高可以实现2.7 kg·m^-2·h^-1的蒸发速率，展示出高效的蒸发速率以及优异的稳定性。1CNT/PVA-SA复合气凝胶蒸发器的制备过程示意图2不同浓度二维和三维CNT10/PVA-SA(6-10)气凝胶在一个太阳光照射下的水蒸发质量变化
- 气凝胶 /
- 定向冷冻 /
- 海水淡化 /
- 水蒸发 /
- 自清洁 /
- 海藻酸钠 /
- 碳纳米管 /
- 聚乙烯醇
Abstract: The desalination evaporator based on the solar interface water evaporation technology can realize the desalination and purification of seawater, but the evaporation rate of the evaporator is low at present. In this work, the composite aerogel of polyvinyl alcohol and sodium alginate was prepared by directional freezing. At the same time, carbon nanotube materials were used as light absorbing materials. The effects of the composition, proportion and content of light absorbing materials of the composite aerogel on the evaporation performance of evaporator water were explored. The research found that the composite aerogel evaporator has a light absorption rate of up to 97% and excellent seawater desalination performance. The water evaporation rate under a sun light can reach 2.7 kg·m⁻²·h⁻¹. In the long-term alternating process of light and darkness, the salt crystals accumulated on the surface of the evaporator will automatically melt and disappear, playing a self-cleaning effect, and can achieve long-term sustainable evaporation. It has broad application prospects in the field of seawater desalination.
- aerogel /
- directional freezing /
- seawater desalination /
- water evaporation /
- self-cleaning /
- sodium alginate /
- carbon nanotube /
- polyvinyl alcohol

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图 1 CNT/PVA-SA复合气凝胶蒸发器的制备过程示意图

Figure 1. Schematic diagram of preparation process of CNT/PVA-SA composite aerogel evaporator

CNT—carbon nanotube;PVA—polyvinyl alcohol; SA—sodium alginate

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图 2 (a)CNT10/PVA-SA (6)的SEM图像，(b)CNT10/PVA-SA (7)的SEM图像, (c)CNT10/PVA-SA (8)的SEM图像，(d)CNT10/PVA-SA (9)的SEM图像，(e)CNT10/PVA-SA (10)的SEM图像，(f)复合气凝胶的宏观图像

Figure 2. (a) SEM image of CNT10/PVA-SA (6), (b) SEM image of CNT10/PVA-SA (7), (c) SEM image of CNT10/PVA-SA (8), (d) SEM image of CNT10/PVA-SA (9), (e) SEM image of CNT10/PVA-SA (10), and (f) macro image of composite aerogel

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图 3 PVA、PVA-SA、CNT10/PVA-SA (6)的接触角测试图

Figure 3. Contact angle test diagram of PVA, PVA-SA and CNT10/PVA-SA (6)

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图 4 (a-d)CNT10/PVA-SA (6)在热板上的红外图像，(e)干态CNT10/PVA-SA (6)在1-5 sun下的红外图像，(f)湿态CNT10/PVA-SA (6)在1-5 sun下的红外图像

Figure 4. (a-d) Infrared image of CNT10/PVA-SA (6) on hot plate, (e) infrared image of dry CNT10/PVA-SA (6)under 1-5 sun, and (f) infrared image of wet CNT10/PVA-SA (6) under 1-5 sun

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图 5 (a) PVA-SA和CNT10/PVA-SA的吸收光谱，(b)一个太阳光照射下CNT(5-20)/PVA-SA的表面温度变化曲线，(c)在一个太阳光照射下CNT(5-20)/PVA-SA的水蒸发质量变化，(d)在一个太阳光照射下不同比例CNT10/PVA-SA(1-5)的水蒸发变化

Figure 5. (a) Absorption spectra of PVA-SA and CNT10/PVA-SA, (b) Surface temperature change curve of CNT(5-20)/PVA-SA under one sunlight, (c) Water evaporation mass change of CNT(5-20)/PVA-SA under one sunlight, (d) Water evaporation mass change of CNT10/PVA-SA(1-5) with different proportions under one sunlight

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图 6 (a)在3 kW·m⁻²的太阳光下产生的水蒸汽的图像(左图)，在2D蒸发下的红外图像(右图)，(b)3D水蒸发测试示意图(左图)，在3D蒸发下的红外图像(右图)，(c)在一个太阳光照射下不同浓度CNT10/PVA-SA(6-10)的2D水蒸发质量变化，(d)在一个太阳光照射下不同浓度CNT10/PVA-SA(6-10)的3D水蒸发质量变化

Figure 6. (a) Image of water vapor generated under the sunlight of 3 kW ·m ^{− 2} (left figure), infrared image under 2D evaporation (right figure), (b) Schematic diagram of 3D water evaporation test (left figure), infrared image under 3D evaporation (right figure), (c) Change of 2D water evaporation quality with different concentrations of CNT10/PVA-SA(6-10) under one sunlight, and (d) Change of 3D water evaporation quality with different concentrations of CNT10/PVA-SA(6-10) under one sunlight

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图 7 (a)脱盐前后，真实海水(中国黄海)中四种主要阳离子的浓度，(b)CNT10/PVA-SA蒸发器表面模拟自然环境的盐沉积/自清洁照片

Figure 7. (a) Concentrations of four main cations in real seawater (Yellow Sea, China) before and after desalination, (b) Photos of salt deposition/self-cleaning on the surface of CNT(10)/PVA-SA evaporator simulating the natural environment

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表 1 不同CNT含量和PVA与SA不同比例的复合气凝胶

Table 1. Composite aerogels with different CNT content and different proportions of PVA and SA

Sample	3 wt%PVA/mL	3 wt%SA/mL	CNT/g
PVA	20	/	/
PVA-SA	10	10	/
CNT5/PVA-SA	10	10	5
CNT10/PVA-SA	10	10	10
CNT15/PVA-SA	10	10	15
CNT20/PVA-SA	10	10	20
CNT10/PVA-SA(1)	10	10	10
CNT10/PVA-SA(2)	6.66	13.3	10
CNT10/PVA-SA(3)	5	15	10
CNT10/PVA-SA(4)	15	5	10
CNT10/PVA-SA(5)	13.3	6.66	10

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表 2 不同PVA与SA浓度的复合气凝胶

Table 2. Composite aerogels with different PVA and SA concentrations

Sample	PVA/5 mL	SA/15 mL	CNT/10 g
CNT10/PVA-SA(6)	1wt%	1wt%	CNT10 g
CNT10/PVA-SA(7)	2wt%	2wt%	CNT10 g
CNT10/PVA-SA(8)	3wt%	3wt%	CNT10 g
CNT10/PVA-SA(9)	4wt%	4wt%	CNT10 g
CNT10/PVA-SA(10)	5wt%	5wt%	CNT10 g

下载: 导出CSV

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