Lamellar Double Hydroxides Intercaled with Humic Substances and Nitrate: Evaluation of Phosphate Removal in Water and Application in Agricultural Sectors

Phosphate species can affect aquatic ecosystems, as excess of this nutrient can cause eutrophication, generating environmental impacts. Lamellar double hydroxides have shown promise in removing phosphate at low concentrations (10-50 mg L 1). In this context, lamellar double hydroxides were synthesized interspersed with nitrates and humic substances, searching for a new product that favors phosphorus adsorption. X-ray diffraction showed the presence of characteristic peaks of lamellar double hydroxides and thermogravimetric analysis showed the decomposition behavior of lamellar structure. The adsorption capacity occurred quickly (< 30 min), being more efficient for lamellar double hydroxides with NO₃. The maximum adsorption capacity showed results of 35.03 and 44.20 mg g 1 for lamellar double hydroxides with humic substances and lamellar double hydroxides with NO₃, respectively. The complexation capacity showed that pH directly influences complexation, being greater for lamellar double hydroxides with humic substances at pH 6.5. Thus, nanostructured materials with humic substances are promising for use in contaminant remediation and adsorption can be a fast and efficient technique for use in soil and water.

Keywords:
lamellar double hydroxides; humic substances; adsorption; phosphate