Study On The Preparation And The Foaming Performance Of Protein Foaming Agent Extracted From Sludge

The residual activated sludge contains large amounts of recyclable material, which is the material basis of its resourcefulness. The organic content of sludge shows high-protein and low-fat features, so sludge can be used to produce protein solution after hydrolysis, filtration, concentration and other process. The foamability of the protein solution is not very good, but it has good foam stability, so it can be made into excellent protein foaming agent by further processing.This paper studied on the original protein solution and its diluted solution by Ross-Miles method as the basic method of detecting the foaming performance of the protein solution. Firstly, the effect of the concentration of the original solution, temperature, pH and various additives on the foaming performance of the protein solution was researched by single-factor experiments. Secondly, the proportioning of the protein solution (the concentration of the original solution, and the amount of the additives) was optimized by the orthogonal experiment. Finally, set up a regression equation between the foaming performance of protein solution and the addition of the additives by the orthogonal regression design.The experiments showed that: the temperature affected the foamability of the protein solution, while the concentration of the original protein solution determined the foam stability of its diluted solution, the higher the concentration, the better the foam stability. Adding little acid or alkali can significantly improve the foaming performance of the protein solution, but adding excess acid was detrimental to the foam stability. By contrast, zinc sulfate, sugar and Arabic gum were the three additives which can significantly improve the foaming performance of the protein solution. The result of the orthogonal experiment showed the best condition for the foaming performance of the protein solution was that the concentration of the original solution was 10% and the additions of the three additives were 0.3g/300ml. Finally, a regression equation was established by orthogonal regression experiment, and analysis showed that the equation accorded with the actual situation well. This article focused on improving the foaming performance of the protein solution from sludge mainly by adding appropriate additives. After a series of experiments, I got an excellent protein foaming agent which had laid a good basis for the application of the protein solution extracted from sludge.