Preparation and modification of porous lightweight ceramsite and its performance investigation

ABSTRACT

In this study, fly ash was used as the main raw material to prepare a lightweight ceramsite which has a specific density close to that of water (0.95–1.05 g/cm³) and good wear resistance. The ceramsite was modified with positively charged iron oxide coating layer by heterogeneous coagulation and coating method. The adsorption property, iron load, bulk density, apparent porosity, compressive strength, surface morphology, surface electrical property, and phase composition of the coating layer were characterized. The optimum modification conditions determined by methylene blue adsorption experiment were: 1 mol/L FeCl₃ solution, calcination temperature 650°C, and calcination time 3 h. The modified ceramsite was covered with an iron oxide layer with uneven thickness. The main crystal phase of the coating layer was α-Fe₂O₃ which exhibited porous structures. The modified ceramsite has a good application prospect in water treatment and purification.

Keywords:

• Iron oxide
• Modification
• Isoelectric point
• Adsorption

Acknowledgments

This study was funded by the Jiangxi Provincial Natural Science Foundation of China (Grant No. 20122BAB203001) and the Jiangxi Provincial Science & Technology Support Project of China (Grant No. 2009AE00800).