engleski

Interactions in Calcium Oxalate Hydrate/Surfactant Systems

Phase transformation of calcium oxalate dihydrate (COD) into the thermodynamically stable monohydrate (COM) has been studied in anionic (sodium dodecyl sulfate (SDS)) and cationic (dodecylammonium chloride (DDACl)) surfactant solutions. Both surfactants inhibited, but did not completely blocked COD to COM transformation: SDS acts as a stronger transformation inhibitor. The inhibition of the transformation process is attributed to the preferential adsorption of surfactant molecules at different crystal faces. Adsorption isotherms for both surfactants followed the two-step (LS) type adsorption model, although some differences in the adsorption behavior were detected. They originated from different ionic and molecular structures of crystal surfaces and the interactions between the surfactant headgroups and crystal surface.

adsorption; calcium oxalate; surfactants

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