Exploring The Adsorption of Nutrients in Industrial Wastewater Using Zeolite

Abstract

Industrial wastewater often contains excess nutrients that can trigger eutrophication if discharged untreated. Zeolite, with its distinct physical and chemical properties, is widely used in wastewater treatment. This work focused on investigating the morphological alterations on the zeolite surface, optimising adsorption operational parameters, and evaluating the adsorption behaviour of ammonium, nitrate, and phosphorus through isotherm and kinetic models. Zeolite was characterised by Scanning Electron Microscopy (SEM), and batch-mode adsorption experiments were operated with varying wastewater percentages (10 - 100% v/v), zeolite dosages (0.4 g - 1.2 g), pH (4 - 9), and contact times (5 - 120 minutes). SEM analysis showed that the initially porous, rough zeolite surface became smoother and less porous after adsorption, confirming nutrient attachment to the zeolite surface. Optimal nutrient removal was achieved at 10% (v/v) wastewater, 1.2 g of zeolite, pH 7, and a 120-minute contact time with agitation at 80 rpm, achieving efficiencies of 32% for ammonium, 67% for nitrate, and 59% for phosphorus. Isotherm analysis showed that ammonium adsorption was better represented by the Freundlich model, nitrate aligned strongly with the Langmuir model, and phosphorus exhibited weak agreement with both models. Also, ammonium and nitrate followed the pseudo-second-order kinetic model, whereas phosphorus was better described by the pseudo-first-order model. The adsorption capabilities of zeolite for nutrient removal were successfully explored, demonstrating its potential as a sustainable treatment option.