Gypsum scale formation and inhibition kinetics with implications in membrane system

Area of Science:

• Environmental Science
• Chemical Engineering
• Materials Science

Background:

• Membrane technology is crucial for addressing water scarcity and pollution.
• Mineral scale deposition and fouling severely impact membrane performance and longevity.
• Accurate prediction of scale kinetics is essential for effective control strategies.

Purpose of the Study:

• Develop a mechanistic model for gypsum crystallization and inhibition kinetics.
• Investigate the transition from homogeneous to heterogeneous nucleation.
• Elucidate the role of inhibitors in prolonging gypsum induction time.

Main Methods:

• Developed a new gypsum crystallization and inhibition model.
• Incorporated classical nucleation theory and Langmuir adsorption isotherm.
• Validated the model against experimental data with and without inhibitors.

Main Results:

• The model accurately predicted gypsum crystallization induction times across wide ranges of temperature, saturation index, and NaCl concentration.
• Inhibitor affinity constants correlated with those for barite, suggesting similar adsorption mechanisms.
• The model accurately predicted gypsum deposition times on membrane surfaces when integrated with a two-phase deposition model.

Conclusions:

• The developed model provides accurate predictions of gypsum crystallization and inhibition.
• It elucidates the mechanisms of gypsum nucleation, crystallization, and inhibition.
• The model offers a tool for optimizing mineral scale control in membrane filtration systems.