纳米颗粒作为稳泡剂泡沫分离酪蛋白的工艺

为了增强乳制品废水中低浓度酪蛋白（casein,CS）的泡沫性能进而提高其泡沫分离效果,首先采用十二烷基二甲基甜菜碱（dodecyl dimethyl betaine,BS12）改性疏水二氧化硅纳米颗粒（silica nanoparticle,SNP）,以制备接触角为61.6°±3.1°的部分疏水二氧化硅纳米颗粒（BS12-SNP）,分别从静态和动态泡沫性能两个角度来研究BS12-SNP作为稳泡剂的功效。实验结果表明,BS12-SNP作为稳泡剂可以抑制泡沫排液和泡沫聚并,进而增强20.0～60.0mg/L酪蛋白的泡沫稳定性。与不添加BS12-SNP相比,添加BS12-SNP后的酪蛋白废水泡沫半衰期最大可提高6.5倍。泡沫分离实验表明,在BS12-SNP浓度50mg/L、气速250mL/min、装液量500mL的条件下,上述浓度范围内的酪蛋白回收率最高可达94.2%,此时富集比为12.3。本文开发了一种表面功能化纳米颗粒代替表面活性剂的泡沫分离工艺,实现了废水中酪蛋白的有效回收。

Technology of foam separation of casein using nanoparticle as a foam stabilizer

In order to enhance the foaming properties of low concentration casein (CS) in dairy wastewater and then improve its performance of foam separation, dodecyl dimethyl betaine (BS12) was used to modify hydrophobic silica nanoparticle (SNP) to prepare a partially hydrophobic SNP (BS12-SNP) with a contact angle of 61.6°±3.1°. This paper studied the effect of BS12-SNP as a foam stabilizer from the static and dynamic foam properties. The results of experiments showed that BS12-SNP could act as a foam stabilizer to inhibit foam drainage and coalescence, thereby enhancing the foam stability of casein (20.0mg/L to 60.0mg/L). The half-life of CS with BS12-modified SNP could be increased by up to 6.5 times compared with that without BS12-SNP. Furthermore, the results of foam separation experiments showed that the maximum recovery percentage of casein at the above concentration range reached 94.2% and the enrichment ratio reached 12.3, under the conditions of the BS12-SNP concentration 50mg/L, air flow rate 250mL/min and liquid volume 500mL. A technology of foam separation with surface-functionalized nanoparticles instead of surfactant was developed and the efficient recovery of casein from its wastewater was realized.