No abstract

Emulsified pickling waste liquid, derived from cleaning oily hardware, cause serious environmental and ecological issues. In this work, a series of grafted (3-aminopropyl)triethoxysilane (APTES) TiO2 pillared montmorillonite (Mt), Ti-Mt-APTES, are prepared and characterized for their assessment in demulsification of acidic oil-in-water emulsion. After titanium hydrate is introduced through ion exchange, montmorillonite is modified by hydrophobic groups coming from APTES. The Ti-Mt-APTES in acidic oil-in-water emulsion demulsification performance and mechanism are studied. Results show that the prepared Ti-Mt-APTES has favorable demulsification performance. The Ti-Mt-APTES demulsification efficiency (ED) increased to an upper limit value when the mass ratio of APTES to the prepared TiO2 pillared montmorillonite (Ti-Mt) (RA/M) was 0.10 g/g, and the 5 h is the optimal continuous stirring time for breaking the acidic oil-in-water emulsion by Ti-Mt-APTES. The ED increased to 94.8% when 2.5 g/L of Ti-Mt-APTES is added into the acidic oil-in-water emulsion after 5 h. An examination of the demulsification mechanism revealed that amphiphilicity and electrostatic interaction both played vital roles in oil-in-water separation. It is demonstrated that Ti-Mt-APTES is a promising, economical demulsifier for the efficient treatment of acidic oil-in-water emulsions.

In this paper, silicon-modified Al powders (SiO2@Al) were prepared by tetraethyl orthosilicate (TEOS) hydrolysis under alkaline conditions. Using SiO2@Al as additives, a new Al2O3-SiO2 ceramic coating (ASMA) was formed on carbon steel to prevent carbon steel from oxidization at 1250 °C for 120 min. Compared with the Al2O3-SiO2 ceramic coating without additive (AS), ASMA showed a remarkably better anti-oxidation performance, especially during the temperature-rise period. According to the characterization conducted by TG-DTA, XRD and SEM-EDS, it was found that the metallic Al in ASMA melted at 660 °C and reacted with SiO2 on its surface, which generated local high temperature and accelerated the sintering of ceramic raw materials. The mullite and hercynite formed in ASMA also played a major role for enhancing the anti-oxidation performance of ceramic coating.