LOW‑COST SUPPORTED MG–AL LAYERED DOUBLE HYDROXIDES ON NATURAL BENTONITE/DOLOMITE FOR FLUORIDE REMOVAL FROM GROUNDWATER

Excess fluoride (F⁻) in groundwater jeopardizes public health in many arid and semi‑arid regions. This extended thesis proposes a low‑cost approach based on Mg–Al layered double hydroxides (LDHs) grown in‑situ on natural mineral supports—bentonite or dolomite—to achieve efficient, regenerable F⁻ removal suitable for decentralized treatment. The concept integrates a constant‑pH co‑precipitation route (pH ≈ 10) using commodity salts, mild aging (≤65 °C), and simple washing, yielding LDH platelets anchored on inexpensive, locally available supports that improve handling and column hydraulics. A compact characterization‑and‑testing workflow (XRD/FTIR/BET/SEM‑EDS, pH pzc, zeta potential; batch adsorption across pH 3–11; kinetic/isotherm modeling; alkaline‑saline regeneration) is defined and translated into engineering guidance (EBCT 2–6 min; alkaline brine regeneration; brine management). The approach is publishable without proprietary instrumentation and provides a replicable pathway for laboratories and water utilities to deploy supported LDHs for defluoridation in practice.