As selenium is toxic at low levels, treatment methods to remove selenium from industrial waste waters are needed. In this work, non-crystalline Mg-Al-CO<sub>3</sub> layered double hydroxide (LDH) in powdered and granular form obtained from commercial sources were evaluated for treatment of selenate-containing deionized, power plant, and flue gas desulfurization (FGD) waters in static jar tests and rapid small scale column tests (RSSCT). Isotherms conducted in spiked DI water fit the Langmuir model and showed a maximum selenate adsorption capacity of 67 mg/g for the calcined LDH powder. The LDH materials showed good capacity for removing selenate from power plant waters that contained very high levels of sulfate and total dissolved solids. By using a dosage of 5 g/L, calcined LDH could remove close to 100% of the selenate from almost all of the power plant waters, including cooling tower blowdown water. With the same dosage, close to 50% of the selenium from FGD water was removed.  RSSCTs were investigated using the granular LDH to treat well water. Removal of sulfate using chemical pre-treatment of the water with barium chloride resulted in about three times higher selenate loading onto the granular LDH. <br/>

Selenium removal from power plant waters using layered double hydroxide materials

253rd National Meeting (2017)

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