Lech Magdalena, Klimek Agnieszka, Porzybót Damian, Trusek Anna
Department of Micro, Nano and Bioprocess Engineering, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.
Membranes (Basel). 2021 Dec 28;12(1):39. doi: 10.3390/membranes12010039.
As biodiesel production as renewable fuel increases, so does the amount of wastewater resulting from this technology. Wastewater is generated during the so-called biodiesel washing, i.e., washing out glycerol and methanol with water. The purified biodiesel must meet international standards, such as EN 14214 or the American ASTM D6751 standard. To fully say that biodiesel technology is environmentally friendly, the amount of wastewater should be minimized. It is also desirable that the purified water can be recycled to the technology. For this purpose, wastewater pre-treated by flotation, during which mainly oils are removed, was subjected to three-stage membrane separation. For each of the stages, the membrane was selected and characterized in terms of its separation capacity and stream stability. Starting with microfiltration, which was mainly aimed at reducing turbidity, affects the permeate flux in the following steps. Then, ultrafiltration and nanofiltration membranes were selected. These membranes were aimed at reducing the concentration of inorganic and organic substances. Consequently the cascade was composed of: MF-0.45 µm, UF-150 kDa, and NF-characterized by an 80% degree of desalination. The final permeate has a salt concentration of less than 0.15 g/L and can be reused in biodiesel technology.
随着作为可再生燃料的生物柴油产量增加，该技术产生的废水量也随之增加。废水是在所谓的生物柴油洗涤过程中产生的，即用清水洗出甘油和甲醇。纯化后的生物柴油必须符合国际标准，如EN 14214或美国ASTM D6751标准。要全面说明生物柴油技术是环保的，就应尽量减少废水量。纯化水能够循环回该技术中也是可取的。为此，对通过浮选预处理的废水（在此过程中主要去除油类）进行了三级膜分离。对于每个阶段，都根据其分离能力和通量稳定性对膜进行了选择和表征。从主要旨在降低浊度的微滤开始，这会影响后续步骤中的渗透通量。然后，选择了超滤膜和纳滤膜。这些膜旨在降低无机和有机物质的浓度。因此，该级联由以下部分组成：MF - 0.45 µm、UF - 150 kDa和NF - 其脱盐率为80%。最终渗透液的盐浓度低于0.15 g/L，可在生物柴油技术中重复使用。
