This study aims to explore oxidized carbon black nanoparticles (OCB-NPs) capped with an inorganic surfactant dispersed in water, as a carbon black water-based nanofluid, on photothermal conversion enhancement. We used ultraviolet–visible (UV–vis) absorption spectroscopy and zeta potential analyzers to identify the optimal concentration of sodium hexametaphosphate (SHMP) as an inorganic surfactant for OCB-NPs in order to determine the maximum value of UV–vis light absorption and absolute zeta potential. Then, the concentrations of 0.025–0.1 wt % OCB water-based nanofluid with SHMP were formulated by an ultrasonic bath for the examination of rheological behavior, thermal conductivity, and heating rate. The results indicated that the heating rate improvement of the water-based nanofluid involving 0.1 wt % OCB-capped with SHMP after irradiation by UV–vis light with wavelengths ranging from 220 to 380 nm, which is included in the solar spectrum, and an intensity of 205 W/m² increased by approximately 66%, compared to the base fluid in the cyclic flow system. Furthermore, after a 1 month storage period, the dispersion stabilization of water-based nanofluid including 0.1 wt % OCB-capped with SHMP reached 98%, as estimated by the UV–vis spectrophotometer.

中文翻译：

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水溶液中氧化碳黑纳米粒子分散体的制备和稳定化，以提高光热转化率

这项研究的目的是探索用分散在水中的无机表面活性剂封端的氧化碳黑纳米颗粒（OCB-NPs），作为碳黑水基纳米流体，以提高光热转化率。我们使用紫外可见（UV-vis）吸收光谱仪和ζ电势分析仪确定了六偏磷酸钠（SHMP）作为OCB-NPs无机表面活性剂的最佳浓度，以确定紫外-可见光吸收和绝对值的最大值。 Zeta电位。然后，用超声波浴配制含有SHMP的0.025-0.1 wt％OCB水性纳米流体，以检测流变行为，导热率和加热速率。结果表明，水基纳米流体的升温速率为0。²增加了大约66％，相比于基础在循环流动系统的流体。此外，根据紫外线可见分光光度计的估计，经过1个月的储存后，包含0.1 wt％OCB的SHMP封端的水基纳米流体的分散稳定性达到98％。