Functionality of nano and 3D-microhierarchical TiO2 particles as coagulants for sericin extraction from the silk degumming wastewater

• Published in: Separation and purification technology 2016-10, Vol.170, p.92-101
• Main Authors: Pakdel, Esfandiar, Wang, Jinfeng, Allardyce, Benjamin J., Rajkhowa, Rangam, Wang, Xungai
• Format: Article
• Language: English
• Subjects: 3D-microhierarchical; Coagulation; Degumming; Nanostructure; Particulate composites; Reduction; Sericin; Settling; Silk; TiO2; Titanium dioxide; Turbidity
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2016.06.025

[Display omitted] •Introducing functionalised TiO2 particles as coagulants for sericin separation.•Comparing the efficiency of nano and 3D-microhierarchical TiO2 particles.•Investigating the role of TiO2 dosage, pH and settling time in sericin removal.•The sericin/TiO2 composites are stable after several cycles of wash. Amine-functionalised TiO2 particles were employed as coagulants to remove sericin from the silk degumming wastewater. Two types of TiO2 particles including 3D-microhierarchical TiO2 (Micron-size) and TiO2 nanoparticles (Degussa P-25) were used in this study. The surfaces of both types of TiO2 particles were functionalised using 3-aminopropyl trimethoxysilane (APTMS). The impacts of TiO2 type, pH, TiO2 concentration, and settling time on sericin removal efficiency were investigated. The efficiency of TiO2 particles in sericin removal was evaluated by measuring the residual turbidity and UV–vis spectra of the solutions before and after the treatment. Moreover, the COD, SDS-PAGE and protein assay tests were conducted to further analyse the treated solutions. The results demonstrated that the sericin removal efficiency of around 67% and turbidity reduction of 95% were achieved at the optimum conditions of 0.04g TiO2, pH=5, and 60min settling time. Nano and micron-size TiO2 particles showed similar efficiency for sericin removal, but micron-size particles outweighed due to their higher efficiency in inducing greater turbidity reduction after 60min. The obtained sericin/TiO2 composites were stable after several cycles of wash and could be useful in different fields including cosmetic, and textile finishing, among others.