Influence of Ca2+ ions on freshly precipitated CaCO3 particles için kapak resmi
Influence of Ca2+ ions on freshly precipitated CaCO3 particles
Majekodunmi, Olukayode Titus, author.
Fiziksel Tanımlama:
xii, 64 leaves: illustrarions, charts;+ 1 computer laser optical disc
The objective of this study was to develop a method to synthesize CaCO3 nanoparticles from a chemical precipitation reaction under ambient and high supersaturation conditions. Equimolar CaCl2 and Na2CO3 solutions were reacted in a tubular reactor at a constant rate. The particles growth inhibition was attempted by dispersing the reaction mixture in a continuously stirred Ca(OH)2 solution. This procedure separated the nucleation phase from the growth inhibition process, and was conducted without pH and composition control. The possibility of impeding the CaCO3 particles overgrowth was explored at different precipitants and Ca(OH)2 concentrations. Their effects on the particles morphology, colloidal stability and specific surface area were studied. Although rapidlysettling particles were produced at precipitants concentration of 100 mM, colloidally stable CaCO3 nanoparticles were obtained at concentrations ≤75 mM. Additive Ca2+ ions, provided by the Ca(OH)2 solutions, inhibited the crystals growth by adsorbing irreversibly on the growth sites. The synthesized particles were as much as 95% smaller than those obtained when pure H2O was used instead. Ca2+ ions concentration and amount of precipitated particles were observed to be important factors for monodispersity and high growth inhibition. Monodisperse and stable nanoparticles were synthesized at low reactants concentration and/or precipitates volume. Vaterite phase was observed in the particles obtained when pure H2O was used as the growth-inhibiting solution. However, the presence of additive Ca2+ ions effected the crystallization of pure calcite, regardless of Ca(OH)2 or precipitants concentration, reaction mixtures retention time in the tubular reactor, volume of precipitates, and the growth-inhibiting solutions initial pH.
Konu Başlığı:

Yazar Ek Girişi:
Tek Biçim Eser Adı:
Thesis (Master)--İzmir Institute of Technology:Chemical Engineering.

İzmir Institute of Technology:Chemical Engineering--Thesis (Master).
Elektronik Erişim:
Access to Electronic Versiyon.


Materyal Türü
Demirbaş Numarası
Yer Numarası
Durumu/İade Tarihi
Tez T002011 TP156.P3 M23 2019

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