For the first time, we have investigated the beneficial effects of non-cavitating coupling fluids and their moderate overpressures in enhancing mass-transfer and acoustic energy transfer in a double cell micro-sonoreactor. Silicon and engine oils of different viscosities were used as non-cavitating coupling fluids. A formulated monoethylene glycol (FMG), which is a regular cooling fluid, was also used as reference. It was found that silicon oil yielded a maximum acoustic energy transfer (3.05 W/cm2) from the double jacketed cell to the inner cell volume, at 1 bar of coupling fluid overpressure which was 2.5 times higher than the regular FMG cooling fluid. It was also found that the low viscosity engine oil had a higher acoustic energy value than that of the high viscosity engine oil. In addition, linear sweep voltammograms (LSV) were recorded for the quasi-reversible Fe2+/Fe3+ redox couple (equimolar, 5 × 10-3 M) on a Pt electrode in order to determine the mass-transport limited current density (jlim) and the dimensionless Sherwood number (Sh). From the LSV data, a statistical analysis was performed in order to determine the contribution of acoustic cavitation in the current density variation |Δj|average. It was found that silicon oil at 1 bar exhibited a maximum current density variation, |Δj|average of ~2 mA/cm2 whereas in the absence of overpressure, the high viscosity engine oil led to a maximum |Δj|average which decreased gradually with increasing coupling fluid overpressure. High viscosity engine oil gave a maximum Sh number even without any overpressure which decreased gradually with increasing overpressure. The Sh number for silicon oil increased with increasing overpressure and reached a maximum at 1 bar of overpressure. For any sonoelectrochemical processes, if the aim is to achieve high mass-transfer and acoustic energy transfer, then silicon oil at 1 bar of overpressure is a suitable candidate to be used as a coupling fluid.

中文翻译：

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使用非空化耦合液来增强声电化学过程。

首次，我们研究了非空化耦合液及其适度的超压在增强双室微声反应器中的传质和声能传递方面的有益效果。硅油和不同粘度的机油被用作非空化耦合液。作为常规冷却液的配制单乙二醇（FMG）也用作参考。已发现，在1 bar的耦合流体超压下，硅油从双层夹套电池到内部电池体积产生的最大声能转移（3.05 W / cm2）比普通FMG冷却液高2.5倍。还发现低粘度机油比高粘度机油具有更高的声能值。此外，记录Pt电极上准可逆的Fe2 + / Fe3 +氧化还原对（等摩尔，5×10-3 M）的线性扫描伏安图（LSV），以确定质量传输极限电流密度（jlim）和无量纲Sherwood数字（Sh）。从LSV数据进行统计分析，以确定声空化在电流密度变化|Δj|平均值中的贡献。发现1 bar的硅油表现出最大电流密度变化，|Δj|平均值为〜2 mA / cm2，而在没有超压的情况下，高粘度机油导致最大值|Δj|平均值，其随时间而逐渐降低耦合液过压增加。即使没有任何过压，高粘度的机油也具有最大的Sh值，但随着超压的增加而逐渐减小。硅油的Sh值随超压的增加而增加，并在1 bar超压时达到最大值。对于任何声电化学方法，如果目标是实现高质量传递和声能传递，则过压为1 bar的硅油是适合用作耦合液的候选材料。