Environmental-Friendly Modifications of Zeolite to Increase Its Sorption and Anion Exchange Properties, Physicochemical Studies of the Modified Materials

Abstract

Zeolites, naturally possessing a high negative surface charge and large specific surface, are used in agriculture as cationic fertilizers, water holders, heavy metals, and organic pollutants sorbents. Since some nutrients occur in anionic forms, there is a need to modify the zeolite surface to hold anions. In this study, hydrogen (hydrochloric acid), iron (Fe2+ and Fe3+), and aluminum cations as well as the influence of sodium hydroxide modifiers on the specific surface area, water vapor, adsorption energy, fractal dimension, mesopore volumes and radii, electrokinetic (zeta) potential, and isoelectric point were investigated. The use of alkali solution did not affect the zeolite properties significantly, whereas hydrogen, iron, and treatments with aluminum cations resulted in an increase in the specific surface area, mesopore volumes, and radii, and a decrease in the water-binding forces. Aluminum cations were the most effective in recharging the zeolite surface from negative to positive, shifting the isoelectric point toward the highest values. Calcination enlarged the negative surface charge and mesopore radius, and diminished the surface area and mesopore volume. The modified zeolites are promising carriers of anionic nutrients, large surface area sorbents, and suppliers of water for plant roots in soil.

Effects of natural and modified zeolite based composite fertilizers on slow release and nutrient use efficiency

“…The availability of more water in the pore channel of zeolite can improve the slow delivery of nutrients to the plant. This unique quality of zeolite is crucial during times of water scarcity, which reduces biomass output, especially in regions where water availability is restricted or where there are large water losses [ 38 ].…”

Zeolite Composite Materials for the Simultaneous Removal of Pharmaceuticals, Personal Care Products, and Perfluorinated Alkyl Substances in Water Treatment

“…The increased influence of negative charges from the acidic functional groups on the shorter carbon chains of both PFBA and PFBS likely contributed to less retention. The surface charges of zeolites are typically negative in water . Although these structures should have been physically capable of adsorbing within channels, increased forces of repulsion may have restricted them from replacing water molecules within the zeolite structure.…”

TiO2/Zeolite Composites for SMX Degradation under UV Irradiation

“…Zeolite is a material with distinctive properties including peculiar ion exchange [25,26], surface acidity, and inexpensive and environmentally benign nature [27,28]. Modifying TiO 2 with zeolites may provide more active surfaces and prevent clotting, significantly improving the photodegradation performance of the catalyst.…”