Kinetics of Struvite Crystals Formation through Adsorption and Crystallization Using Zeolite Modification

Eko Ariyanto; Dian Kharismadewi; Mardwita Mardwita; Stefanus Muryanto

doi:10.24996/ijs.2024.65.1.1

Authors

Eko Ariyanto Departement of Chemical Engineering, Engineering Faculty, Universitas Muhammadiyah Palembang, Palembang, Indonesia
Dian Kharismadewi Departement of Chemical Engineering, Engineering Faculty, Universitas Muhammadiyah Palembang, Palembang, Indonesia
Mardwita Mardwita Departement of Chemical Engineering, Engineering Faculty, Universitas Muhammadiyah Palembang, Palembang, Indonesia
Stefanus Muryanto Department of Chemical Engineering, UNTAG University, Semarang, Indonesia

DOI:

https://doi.org/10.24996/ijs.2024.65.1.1

Keywords:

Struvite, Natural Zeolite, Crystallization, Equilibrium Studies

Abstract

This study observed the formation of struvite crystals in wastewater using natural zeolite activated with Mg²⁺ ions. Mg²⁺ ions released from natural zeolite would react with PO₄^3- and NH₄⁺ ions from in wastewater to form struvite crystals. The results showed that at pH 8.5, the removal of PO₄^3- and NH₄⁺ ions was more effective using the modified zeolite than the natural zeolite. Adding 40 g/L Zeo-Mg (1) produced the best results, with PO4^3- (93.32%) and NH₄ (40%) adsorption. Meanwhile, 40g/L Zeo-Mg (2) adsorbed 81% PO₄^3- ions and 27.12% NH₄⁺ ions. The eqilibrium time of all the treatments was 40 min. The results of observation through SEM, EDX, and FTIR showed that struvite crystals were formed on the zeolite surface. Kinetic models indicated that the mechanism of struvite formation on the surface of natural and modified zeolite was mainly chemisorption. Further calculations showed that the adsorption of PO₄^3- and NH₄⁺ ion followed the pseudo-first-order kinetic model.