BACKGROUND: Layered double hydroxide nanoparticles have been extensively investigated and exploited for the removal of harmful anions from contaminated water. For adsorption of acid yellow dye (AY) from contaminated water, nitrate-intercalated MgAl layered double hydroxide (LDH) nanoparticles were synthesized using the co-precipitation method with the refluxing condition in a nitrogen atmosphere.RESULTS: The X-ray diffraction pattern of LDH nanoparticles showed that LDH nanopowder with nitrate in the interlayer position was successfully synthesized. The shift in (003) basal plane diffraction peak to a lower angle (2θ) of 7.75°in the LDH-AY from 10.40°in the pristine LDH confirmed the intercalation of AY in the interlayer space of LDH. Variable factors for the adsorption of the AY on the LDH nanoparticles were examined in the batch process using ultraviolet-visible spectroscopy and those included the adsorbent dose (5-30 mg), the incubation time (3-60 min), the temperature (25-50 °C), the pH of the AY aqueous suspension (5-9) and the AY concentration (0.03-0.1 mg mL −1 ). Box-Behnken design was used to optimize the three independent variables of temperature, incubation time and pH of AY solution for the adsorption of the dye. The optimized values of the incubation time, temperature and pH were found to be 25.89 min, 35.99 °C and 5.16, respectively. A maximum adsorption rate of 0.00515 g mg −1 min −1 of AY onto LDH nanoparticles was found at a solution pH of 5 and a temperature of 50 °C. The adsorption kinetics of the AY at different suspension pH values and temperature followed a pseudo-second-order kinetic model. Furthermore, an adsorption isotherm study for the adsorption of AY at a temperature of 40 °C and pH 5 followed a Langmuir isotherm model, and the maximum adsorption capacity of the AY was calculated to be 412.55 mg g −1 with excellent regeneration capacity.CONCLUSION: The study revealed that the synthesized nitrate intercalated Mg Al LDH nanoparticles using the reflux conditions offered promising potential to adsorb acid yellow 36 dye form its aqueous solution.

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