Modified natural zeolites for enhanced nutrient uptake

• Main Author: Rafaee, Mutiara Iman
• Other Authors: Lam Yeng Ming
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Materials
• Online Access: https://hdl.handle.net/10356/153061
• Institution: Nanyang Technological University

The introduction of soilless agriculture brought about advantages in being much less labour intensive, more hygienic, and better soil control as compared to traditional means. Zeolites are a popular soilless plant growth substrate, possessing attractive properties such as low cost, high water retention, high cationic exchange capacities, low density, and high stability. However, zeolites are known to have poor affinity towards anionic nutrients due to its intrinsic negative charge. This project aims to obtain a more in-depth understanding in natural zeolite’s nutrient uptake. It is followed by surface modification to develop a polymer-zeolite composite to enhance nutrient loading capability, especially towards anionic nutrients such as PO4 and SO4 which is essential for plant growth. Surfactant-modified and chitosan-modified zeolites were developed at different modification ratio, further subject to systematic nutrient uptake tests which vary electrical conductivity of nutrient solution and nutrient loading time. Both modified zeolites exhibited improved anion uptake ability without undermining their cation uptake. Surprisingly, compared with pristine zeolite there is a 400 ppm increase in PO4 adsorption and 100 ppm increase for SO4 on chitosan modified zeolites. The results show great promises towards the application of modified zeolite as a slow-release fertiliser for self-sustained plant growth.