Characterization of Nanoporous Ceramic Granules Made with Coal Fly Ash and Their Utilization in Phenol Removal from Water

Coal fly ash has been evaluated as low-cost material for pollutants adsorption. But powdered fly ash is difficult to be separated from the adsorbate and solution after saturation. When it is made into granules, this problem can be solved. Granules with uniform diameter of 6mm were prepared and used as adsorbents for phenol removal from aqueous solution. The physical and chemical characteristics of the granules were investigated. The data indicated that the granules were abundant with nanosize pores of 9.8 nm on average. The specific surface area and porosity reached 130.5m(2)/g and 60.1%, respectively. The main components in the granules were SiO2, Al2O3, MgO, Fe2O3, CaO, K2O, and unburned carbon. The adsorption batch experiments showed that this granular material was an efficient adsorbent for phenol removal. Phenol adsorption on the granules was mainly influenced by dosage and contact time. Increase in the dosage could enhance phenol adsorption effectively. More than 90% phenol could be removed under normal temperature and neutral pH with initial concentration of 100mg/L, contact time of 90 min, and dosage of 140 g/L. The adsorption of phenol on the granules was spontaneous and complied well with the pseudo-second-order model and Langmuir isotherm model.