A study on regenerated zeolite adsorption capacity for ammonical nitrogen and COD removal from leachate

Abstract

Leachate pollutant in the form of amnonical nitrogen (NH4-N) and chemical oxygen demands (COD) is becoming more important to avoid problems to aquatic as well as human life. The goal of this present study is to investigate the removal of such pollutant using zeolite media at different condition. The different technologies like air stripping, membrane filtration, chemical precipitation, electrolytic treatment and reverse osmosis are used but are expensive to build, operate and also maintain the system. The physio-chemical treatment or ion exchange/adsorption is preferred over the other methods because of its stability, simplicity, easy maintenance and quality control. The batch experiments were investigated at 350rpm for 60minutes to evaluate the natural zeolite and regenerated zeolite capacity by using Freundlich Isotherm. The equilibrium adsorption data is fit and followed Freundlich isotherm for natural Zeolite (Kf = 0.0530, 1/n = 0.2326 and R2 = 0.9727) and regenerated Zeolite (Kf = 0.1337, 1/n = 0.1669 and R2 = 0.9621) for NH4-N. As for the COD natural Zeolite (Kf = 0.0113, 1/n = 0.4612 and R2 = 0.9822) and regenerated Zeolite (Kf = 0.0123, 1/n = 0.0932 and R2 = 0.9938). The removal observed were 20.7%, 28.2% for NH4-N and 18.6%, 19.5% for COD for both natural and regenerated Zeolite, respectively. The Freundlich’s Isotherm equation shows stronger bond are made by NH4-N compared to COD represented by the Isotherm Kf value. However regenerated Zeolite performance in removing NH4-N and COD is higher than natural Zeolite due to the high ion exchange selectivity on Na+. Whereby the NH4-N is replaced much easier when the absorbent pores is fill up by Na+ ion. The capacity of the regenerated Zeolite remains almost the same up to 10 times of regeneration. Hence serve as an effectively adsorption material in waste water treatment as recyclable adsorption material.