ESTIMATING THE ZETA POTENTIAL IN DOLOMITE-BRINE SYSTEMS TO RECOVER CRITICAL METALS FROM BRINE DEPOSITS

Zeta potential is a crucial parameter in electrokinetics for determining sorption and water-rock reactions of ionic species in solution. It varies in water-rock systems depending on factors such as rock mineral composition, ionic strength, temperature, and pH. The growing demand for lithium and cobalt, key components in energy storage technologies like lithium-ion batteries (LIBs), has been driven by the global shift towards green energy. Previous studies have identified high lithium concentrations in produced water brine (PWB).

This study investigated the sorption of cobalt and lithium using low-cost natural dolomite as a sorbent. Adsorption experiments elucidated the role of alkalinity in the high removal of Pb, Ba, Sr, Cd, and Pb, as well as the effective recovery of Li and Co from PWB through sorption and precipitation reactions on dolomite under low pH and high temperature conditions. Zeta potential measurements revealed a consistent decrease with increasing pH, transitioning from positive values in acidic conditions to negative values in alkaline environments. The isoelectric point was observed between pH 6 and 8 across the studied temperature range (20-50°C). Increasing temperature generally reduced the magnitude of zeta potential, with this effect being more pronounced at neutral and alkaline pH.

These findings provide valuable insights into dolomite's surface charge behavior under reservoir-relevant conditions, crucial for understanding and optimizing processes such as enhanced oil recovery, metal adsorption, and mineral precipitation in carbonate systems. This study demonstrates that dolomite filtration is an effective and inexpensive alternative for removing both divalent toxic metals and monovalent critical metals. The results address environmental concerns while also highlighting potential opportunities for critical metal recovery from produced water, contributing to both environmental remediation and resource recovery efforts.