Modified starch flocculants with quaternary ammonium groups

Wednesday, September 6, 2017 - 10:00
Rectorate Hall (K. Donelaicio St. 73-402 room)

Author, Institution: Edita Lekniutė-Kyzikė, Kaunas University of Technology

Science Area, Field of Science: Technological Sciences, Chemical Engineering – 05T

Summary of the Doctoral Thesis: Summary

Scientific Supervisor:Assoc. prof. dr. Joana BENDORAITIENĖ (Kaunas University of Technology, Technological Sciences, Chemical Engineering  - 05T).

Dissertation Defence Board of Chemical Engineering Science Field:
Prof. dr. Raimundas ŠIAUČIŪNAS (Kaunas University of Technology, Technological Sciences, Chemical Engineering, 05T) – chairman;
Prof. dr. Saulutė BUDRIENĖ (Vilnius University, Physical Sciences, Chemistry, 03P);
Assoc. prof. dr. Andra DĖDINAITĖ (KTH Royal Institute of Technology, Physical Sciences, Chemistry, 03P);
Prof. habil. dr. Juozas Vidas GRAŽULEVIČIUS (Kaunas University of Technology, Technological Sciences, Chemical Engineering, 05T);
Assoc. prof. dr. Jolita OSTRAUSKAITĖ (Kaunas University of Technology, Technological Sciences, Chemical Engineering, 05T).

The doctoral dissertation is available on the internet and at the library of Kaunas University of Technology (K. Donelaičio g. 20,Kaunas)

Synthetic flocculants are used for water treatment, sewage treatment and destabilization of other disperse systems. However they are not biodegradable or their degradation products are toxic. Starch, which is biodegradable, its degradation products are environmentally friendly, and is derived from renewable sources, is an excellent source of effective flocculants that can be a suitable alternative to synthetic flocculants.
The aim of the work was to develop an effective biodegradable modified starch flocculant with quaternary ammonium groups which would be suitable for removing negatively charged pollutants and for thickening the municipal sewage sludge.
A novel hydromechanical method for obtaining starch flocculants was proposed and the conditions of obtaining an efficient and biodegradable optimal structure ionogenic starch flocculant were selected. The dependence of biodegradability on the degree of substitution was determined. According to the model systems and municipal wastewater destabilization studies, the flocculation mechanism of new modified starch derivatives was proposed. It was determined that the sheared cross-linked cationic starch derivative is the most suitable for thickening municipal sewage sludge; the floccules resistant to mechanical stress are obtained when using this derivative. A technological scheme for the production of flocculant was invented and a prototype was produced in the pilot of equipment and tested in the water treatment company.