Sustainable zeolite production via solar calcination of kaolin and halloysite: structural evolution, phase control, and CO₂ adsorption efficiency

Date

2025-7-21

Author

Paşabeyoğlu, Pelin

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

12806
views

0
downloads

Cite This

The production of zeolites from natural clays offers a promising route toward low-cost and sustainable adsorbent materials, especially for applications in carbon capture. However, conventional calcination processes used to activate kaolin and halloysite clays are highly energy-intensive and carbon-emitting. This thesis explores solar-driven calcination as an environmentally benign alternative for clay activation, aiming to reduce the carbon footprint of zeolite synthesis without compromising material performance. Kaolin and halloysite were subjected to concentrated solar thermal treatment at temperatures ranging from 700 °C to 1000 °C to induce structural transformations into amorphous metaforms and Al–Si spinel intermediates. The thermally activated products were then converted into LTA- and FAU-type zeolites via alkali hydrothermal synthesis. Phase evolution and porosity development were investigated using various characterization techniques. Special attention was given to kaolin, an abundant and low-cost clay that is extensively mined in Türkiye and offers strategic advantages for sustainable materials development. The influence of precursor type and calcination conditions on zeolite formation pathways was systematically evaluated. CO₂ adsorption capacities of the resulting zeolites were assessed at 25 °C and 1 bar using breakthrough and equilibrium measurements. Results demonstrate that solar-calcined clays yield zeolites with comparable crystallinity, surface area, and CO₂ uptake to those produced via conventional heating, while achieving significant reductions in thermal energy consumption and CO₂ emissions. This work validates solar calcination as a viable route for scalable zeolite production and supports the integration of clay-based zeolites into low-cost, low-carbon CO₂ capture technologies.

Subject Keywords

Solar calcination, Kaolin and halloysite, Zeolite 4A and 13X, Al–Si spinel, CO₂ capture

URI

https://hdl.handle.net/11511/115512

Collections

Graduate School of Natural and Applied Sciences, Thesis