Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment & Technology, Wuxi 214122, China; School of Mechanical Engineering, Jiangnan University, Wuxi 214122, China; Wuxi General Machinery Works Co. Ltd., Wuxi 214028, China.
Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment & Technology, Wuxi 214122, China; School of Mechanical Engineering, Jiangnan University, Wuxi 214122, China.
Water Res. 2024 Nov 15;266:122338. doi: 10.1016/j.watres.2024.122338. Epub 2024 Aug 26.
Microplastics have attracted considerable attention as emerging contaminants that threaten water bodies. The removal of microplastics from a mini-hydrocyclone, enhanced by air flotation, was studied numerically. The three-phase flow was modeled using the Eulerian-Eulerian model coupled with interphase interactions. The characteristics of the flow field and distribution of microplastics and microbubbles were discussed, and the mechanism of cyclonic air flotation separation was analyzed. It was found that injecting microbubbles accelerated the axial migration of microplastics and moved the enriched area upward toward the overflow. The coalescence rate of the bubbles near the axis was higher than their breakage rate, which led to the formation of an air core. The length and diameter of the air core increased with the inlet gas holdup. When the air core size closely matched the overflow, the constrained flow channel prevented the discharge of microplastics. The optimal air holdup must be determined to ensure the efficiency of the cyclonic air flotation process. The sizes of the microbubbles used for cyclonic air flotation should be comparable to those of the separated microplastics. The upper cone angle significantly promoted the migration of microplastics to the axis. This study was conducted to purify microplastic-containing wastewater using an environmentally friendly and energy-efficient technique and to provide a theoretical basis and practical reference for applying microplastic separation technology in water.
微塑料作为新兴污染物，对水体造成了威胁，引起了广泛关注。本文采用欧拉-欧拉模型并耦合相间相互作用对微型水力旋流器增强空气浮选去除微塑料进行了数值模拟。讨论了流场特性、微塑料和微气泡的分布，并分析了旋流空气浮选分离的机理。研究发现，注入微气泡会加速微塑料的轴向迁移，并将富区向上移动到溢流口。轴附近气泡的聚并速率高于破裂速率，从而形成了一个空气核。空气核的长度和直径随入口气含率的增加而增加。当空气核尺寸与溢流口相匹配时，受限的流道会阻止微塑料的排出。为了确保旋流空气浮选过程的效率，必须确定最佳的气含率。用于旋流空气浮选的微气泡尺寸应与要分离的微塑料相当。上锥角显著促进了微塑料向轴的迁移。本研究旨在采用环保且节能的技术净化含微塑料废水，为在水中应用微塑料分离技术提供理论依据和实际参考。
