Entrapment of Mg−Al layered double hydroxide into alginate/polyvinyl alcohol beads for water remediation

Mg−Al LDH-alginate/PVA beads were fabricated by entrapment of the Mg−Al LDH powder into alginate/PVA beads. This study has demonstrated the potential use of this technique in environmental remediation using nitrate as a model contaminant. The obtained Mg−Al LDH-alginate/PVA beads were characterized by X-ray diffraction and scan electron microscopy. Batch adsorption experiment showed that the nitrate sorption process on the Mg−Al LDH-alginate/PVA beads followed pseudo-second-order reaction kinetic model and the adsorption isotherm date showed that the Langmuir isotherm was more appropriate at describing the experimental results than the Freundlich isotherm. In the column study the flow rate and inlet nitrate concentration were maintained at 24.84 m3/m2 h and 25 mg N/L, respectively. Using 15 cm column bed depth, the breakthrough and exhaust time found were 8 and 28 h, respectively. The percentage of nitrate removal by column was 67.10. The value of adsorption rate coefficient (K) and the adsorption capacity coefficient (N) were 0.0045 L/mg h and 475.67 mg/L, respectively.