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使用的化学试剂和溶剂都是从商业渠道购买,使用前并未经进一步纯化。纤维素纸购自Cytiva生命科学有限公司,氯仿购自Xilong科学股份有限公司,Y6购自Hyper光电科技有限公司。
热重分析(TGA)和差示扫描量热分析(DSC)在TA Q600型仪器上测试,加热速率为10 K/min。用Angilent Cary
5000 分光光度计记录紫外-可见(UV-Vis)吸收光谱。采用扫描电镜(JEOL JSM-6700F)对纤维素纸的形貌进行观察。采用接触角测量仪(Dataphysics-OCA20)记录样品的水接触角。采用红外热成像仪(FLIR-C5)和接触式温度计(UNI-T, UT325)记录样品的温度变化。利用CEL-HXF300型号的氙气光源(AM 1.5G光谱滤波器)进行了水蒸发和热电发电实验。发电选用商用热电片(TEC1-12706,长40 mm,宽40 mm,高3.6 mm)。输出电压由Keithley 2612系统源表测量和记录。采用电感耦合等离子体发射光谱(ICP-OES, PE Avio 200)测定蒸发前后的金属离子浓度。
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将Y6在低沸点溶剂氯仿中充分溶解后,喷洒在纤维素纸上并自然挥发除去残余溶剂。将基于纤维素纸的蒸发器放在1个装满模拟海水的小烧杯内。太阳光由带有AM 1.5G标准光谱滤光片的太阳模拟器产生,在特定的光强度下照射在样品上。用电子天平测量水的失重,通过接触式温度计记录整个过程的温度。
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光热水蒸发过程中太阳能的光热转换效率η计算公式如下[15]:
$$ \eta=\dot{m} h_{\mathrm{LV}} / q_i $$ (1) 式中:
ṁ ——蒸发速率[kg/(m2·h)],太阳光照下水的蒸发速率ṁ = ṁlight−ṁdark,在我们的工作中ṁdark = 0.102 55 kg/(m2·h);
qi ——功率密度(mW/cm2),为太阳光模拟器在水蒸发实验过程中的功率密度;
hLV ——液-气相变总焓(kJ/kg),计算公式为:
$$ h_{\mathrm{LV}}=C \Delta T+\Delta h $$ (2) 式中:
C ——水的比热容[4.18 J/(g·K)];
ΔT ——水的升高温度(℃);
Δh ——相对温度下的蒸发焓(kJ/kg)。根据研究报道,hLV约为2 256.4 kJ/kg。
对于Y6蒸发器:
$$ \begin{gathered} \dot{m}_{\text {light }}=1.130\;67 \mathrm{~kg} /\left(\mathrm{m}^2 \cdot \mathrm{h}\right) \\ \dot{m}_{\text {dark }}=0.102\;55 \mathrm{~kg} /\left(\mathrm{m}^2 \cdot \mathrm{h}\right) \\ \dot{m}=\dot{m}_{\text {light }}-\dot{m}_{\text {dark }}=1.028\;12 \mathrm{~kg} /\left(\mathrm{m}^2 \cdot \mathrm{h}\right) \\ h_{\mathrm{LV}} \approx 2\;256.4 \mathrm{~kJ} / \mathrm{kg}\\ q_{\mathrm{i}}=100 \mathrm{~mW} / \mathrm{cm}^2 \\ \eta = \frac{{\dot m{h_{{\rm{LV}}}}}}{{{q_{\mathrm{i}}}}} = 64.4\text{%} \end{gathered} $$ -
将条状纤维素纸粘在热电器件的上表面,纤维素纸的两端与热电器件的下表面和水接触。将Y6纤维素纸粘在条状纤维素纸的上表面,用聚苯乙烯泡沫作为漂浮承载体。分别在1.0 kW/m2和3.0 kW/m2模拟太阳光照射下进行光热发电,用源表测量并记录电压。
Application of Wide Spectrum Conjugated Small Molecule for High Efficiency Solar-Powered Seawater Desalination and Power Generation
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摘要:
目的 为解决太阳能海水淡化器件成本高、制备工艺复杂的难题,选择具有重量轻、成本低、合成及提纯工艺简单等优点的有机小分子光热材料作为太阳能吸收材料。 方法 利用1种有机共轭小分子Y6,与低成本的纤维素纸结合,制备了在350~ 1000 nm范围内宽光谱吸收的高光热转换性能的Janus结构水蒸发器。结果 蒸发器的下表面具有高效的水粘附性,利于高速集水,而蒸发器的上表面具有拒水性,能够达到理想的自漂浮能力。并且每3.14 cm2的器件仅需0.5 mg光热材料就能实现超过70 ℃的温度,节约用料优势明显。 结论 在1.0 kW/m2太阳光辐照下,基于Y6的蒸发器的光热能量转换效率为64.4%,蒸发速率高达1.13 kg/(m2·h),明显高于对照的纤维素纸蒸发器。经过太阳能蒸发脱盐后,得到的纯化水的离子浓度相比于初始的模拟海水显著降低4~6个数量级。该蒸发器与热电器件集成,在1.0 kW/m2太阳光照射下,蒸发速率达到1.02 kg/(m2·h),同时还产生了55 mV的输出电压。研究结果表明,基于有机小分子Y6的太阳能蒸发器,在光热水净化和热电发电协同作用方面具有良好的应用前景。 Abstract:Introduction In order to solve the problems of high cost and complex preparation process of solar desalination devices, organic small molecule photothermal materials, which possess advantages such as light weight, low cost, simplified synthesis and purification processes, are selected as solar energy absorption materials. Method A kind of organic conjugated small molecule Y6 was combined with a low-cost cellulose paper to prepare a Janus structure water evaporator with wide spectrum absorption in the range of 350~1 000 nm and high photothermal conversion performance. Result The bottom surface of the evaporator has efficient water adhesion, facilitating rapid water collection, while the top surface has water repellency, which can achieve the self-floating ability. Moreover, each 3.14 cm2 device only needs 0.5 mg photothermal material to achieve a temperature of more than 70 ℃, demonstrating significant material-saving advantages. Conclusion Under 1.0 kW/m2 solar irradiation, the photothermal conversion efficiency of Y6-based evaporator is 64.4%, and the evaporation rate is up to 1.13 kg/(m2·h), which is obviously higher than that of the control cellulose paper evaporator. After solar evaporation desalination, the purified water obtained exhibits a significant reduction in ion concentration by 4~6 orders of magnitude compared to the initial simulated seawater. When the evaporator is integrated with a thermoelectric device, the evaporation rate reaches 1.02 kg/(m2·h) under 1.0 kW/m2 solar irradiation. Meanwhile, an output voltage of 55 mV is generated. This study demonstrates that the solar evaporator based on organic small molecule Y6 has a promising application prospect in the synergistic effect of photothermal water purification and thermoelectric power generation. -
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