Influence of Sodium Dodecyl Sulfate and Static Magnetic Field on the Properties of Freshly Precipitated Calcium Carbonate

Abstract

Properties of calcium carbonate precipitated from aqueous solutions of CaCl(2) and Na(2)CO(3) in the presence of sodium dodecyl sulfate (SDS) and S-S 0.1 T magnetic field (MF) were studied. The nucleation and precipitation processes of CaCO(3) were investigated by pH and zeta potential measurements at 20 +/- 1 degrees C up to 2 h after mixing the solutions. Also the amounts of calcium carbonate deposited on the glass surfaces and its structure were examined. It was found that SDS influences the kinetics of precipitation, crystallographic forms, and crystal size of CaCO(3). The SDS effects are more pronounced in MF presence. A small amount of SDS accelerates transformation of vaterite into calcite, whereas increasing surfactant concentration moderates such a transformation. On the other hand, in all the systems, MF in the presence of SDS causes a slower transformation of vaterite into calcite. These effects are reflected in pH and zeta potential changes, although there is no clear dependence between the SDS amount present during the precipitation and changes of the parameters investigated. It seems that MF effect is most significant at a defined optimal SDS concentration. The results, however, do not allow suggestion of any detailed mechanism of the field interaction.

Effects of a static magnetic field on water and electrolyte solutions

“…The effects of these fields still attract much research. The changes caused by MF depend on many factors, such as the field strength [1][2][3]17], the direction of the applied field [13], the time of the magnetic exposure [1,16,17], the flow rate of the solutions [9,10,24], the additives present in the system [6][7][8]11], and the pH [12,15]. The effects caused by external MF lasted even up to 200 h after the field had ceased [9].…”

“…Especially, MF effects on calcium carbonate and calcium sulfate precipitation processes and their suspensions have been investigated extensively [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. This is because of the problem of hard scale formation.…”

“…This is because of the problem of hard scale formation. It was found that the presence of static MF increases aragonite formation, which is less adhesive than calcite [2,3], altered the ζ potential of colloidal particles [6,7,11,17], and promoted homogeneous precipitation of CaCO 3 [21]. However, reproducibility of carried out experiments was very often low.…”

Effect of Surfactants on CO2 Biomineralization with Sporosarcina pasteurii and Bacillus megaterium

“…Except when CTAC was added, residual calcium concentration profiles had a very similar trend in all the experiments with S. pasteurii (Fig. 3a), where calcium concentration decreased from 2.5 to 0.24 mmol after 48 h. It has been known that in the presence of SDS in CaCO 3 , precipitation reaction can regulate the crystal size and amount of precipitate depending on the surfactant content (Chibowski et al 2005). In the presence of SDS, negatively charged head groups of surfactant probably adsorb on the initially positively charged CaCO 3 surface and promote its phase transformation (Heywood and Mann 1994).…”

Study on the Effect of A Magnetic Field on Pb(II) Removal Using Modified Chitosan

“…It has been demonstrated in recent years that magnetic fields influence the physicochemical properties of water and aqueous solutions and suspensions [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Different hypotheses for the influence of magnetic fields on water and aqueous solutions have been extensively studied [25][26][27].…”