(The) dispersion stability of precipitated caclium carbonate particles with adsorbed APG layers계면활성제가 흡착된 침강성 탄산칼슘 입자의 분산 안정성에 관한 연구

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The electrostatic and rheological properties of precipitated calcium carbonate suspension adsorbed with surfactant layers were investigated. In this experiment, alkyl polyglycoside (APG) and sodium stearate was used as coating materials of calcium carbonate particle. The pH of suspension was adjusted to 6, 8, and 12 by using HCl and NaOH standard solution to investigate the pH effect (various surface charge effects) on adsorption of APG surfactant onto calcium carbonate particle. As an electrostatic property of particle, zeta potential was measured by using electrophoretic method and viscosity of suspension was investigated using rheometrics with Coutte geometry. From the measurement of suspension viscosity, yield value of suspension with surfactant concentration was determined using Casson equation. The dispersion stability of suspension was determined by measurement of settling time and compared with other properties of calcium carbonate suspension. Total potential energy of calcium carbonate in aqueous medium was calculated using DLVO theory and the minimum surface potential to disperse calcium carbonate particle stably without surfactant adsorption was revealed as 28mV. The adsorption amount of APG onto calcium carbonate particle was exhibited to depend on surface charge of particle. The higher surface charge, the more amount of APG was adsorbed onto particle surface and by the adsorption of APG molecules, the surface potential of calcium carbonate particle was markedly decreased. This indicates that APG molecule has a negative charge in solution. In low APG concentration, the dispersion stability of suspension does not show a relationship with zeta potential at all suspension pHs and exhibits very poor stability. This indicates that the hydrophobic interaction among particles caused by hydrophobic surface property destabilizes the suspension, and this destabilization region continued to monolayer coverage of surfactant layer. After this monolayer satur...
Advisors
김종득researcherKim, Jong-Dukresearcher
Description
한국과학기술원 : 화학공학과,
Publisher
한국과학기술원
Issue Date
1998
Identifier
133657/325007 / 000963319
Language
eng
Description

학위논문(석사) - 한국과학기술원 : 화학공학과, 1998.2, [ viii, 76 p. ]

Keywords

Zeta potential; Alkyl polyglycoside; Surfactant; Viscosity; 점도; 제타 포텐션; 탄산칼슘; 알킬 폴리글리코사이드; 계면활성제

URI
http://hdl.handle.net/10203/29607
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=133657&flag=dissertation
Appears in Collection
CBE-Theses_Master(석사논문)
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