STUDY ON ADSORPTION OF NITRATE BY WATER HYACINTH (Eichhornia crassipes) BIOCHAR

Abstract

The purpose of the article is studying on adsorption capacity of nitrate ions in solutions by biochar prepared from water hyacinth under conditions including pH, adsorbent dosage, contact time and and initial NO₃^- ion concentration. Experimental data were applied to apparent kinetic models (pseudo-first-order model and the pseudo-second-order model); adsorption equilibrium according to Langmuir isotherm model and Freundlich adsorption isotherm model. The result of the maximum adsorption capacity of nitrate ions by water hyacinth biochar was 5.9597 mg g^-1 at pH = 4; the adsorbent dosage was 1 g; the contact time was 120 minutes and the initial nitrate ion concentration in the solution was 50 mg NO₃^- L^-1. The removal of NO₃^- fitted both the pseudo-first-order model and pseudo-second-order kinetic model. The Langmuir isotherm showed a better fit than the Freundlich isotherm. Thus, water hyacinth biochar can be used to treat nitrate ions in water or wastewater containing NO₃^- ions.