Tang Jianping, Zhang Yachao, Yao Yansheng, Dai Nianwei, Ge Zhangsen, Wu Dong
School of Mechanical and Electrical Engineering, Anhui Jianzhu University, Hefei, Anhui 230601, China.
CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230026, China.
Langmuir. 2021 Jun 15;37(23):6947-6952. doi: 10.1021/acs.langmuir.1c00437. Epub 2021 Jun 1.
Aeration is a mass transfer process, in which gas is dispersed into a liquid by utilizing air inflation or agitation. Typically, a microporous device is often used for aeration. Increasing the gas flow rate and decreasing the pore size reduce the bubble size, but the surface wettability of the gas/solid interface also has a significant impact on the bubble size, which is rarely studied. In this study, a superhydrophilic/superhydrophobic Janus aluminum foil (JAF) is fabricated by laser microstructuring and low surface energy modification. The gas-repelling superhydrophilic surface not only facilitates ultrafine bubble generation but also allows the bubbles to detach from the aerator surface quickly, while the superhydrophobic surface prevents water from infiltrating into the aeration chamber and reduces the mass transfer resistance. The micropores with different diameters are obtained by adjusting the laser processing parameters. The pore prepared by the laser is uniform, consequently leading to the uniform bubble size. When the pore diameter is set to 30 μm, the diameter of bubbles released from the superhydrophilic surface of the JAF is only 0.326 mm, and the gas dissolution rate is about six times that of the double-sided superhydrophobic aluminum foil. This simple, low-cost, and controllable method of the laser processing JAF has broad applications in wastewater treatment, energy production, and aquaculture.
曝气是一种传质过程，其中气体通过空气充气或搅拌分散到液体中。通常，微孔装置常用于曝气。增加气体流速和减小孔径会减小气泡尺寸，但气/固界面的表面润湿性对气泡尺寸也有显著影响，而这方面的研究很少。在本研究中，通过激光微结构化和低表面能改性制备了一种超亲水/超疏水双面铝箔（JAF）。拒气的超亲水表面不仅有助于产生超细气泡，还能使气泡迅速从曝气器表面脱离，而超疏水表面可防止水渗入曝气腔并降低传质阻力。通过调整激光加工参数可获得不同直径的微孔。激光制备的孔均匀，从而导致气泡尺寸均匀。当孔径设置为30μm时，从JAF超亲水表面释放的气泡直径仅为0.326mm，气体溶解速率约为双面超疏水铝箔的六倍。这种简单、低成本且可控的激光加工JAF方法在废水处理、能源生产和水产养殖等领域具有广泛应用。
