Fly Ash Sintered Ceramiste Preparation And Enhanced Removal Of Phosphate In Wastewater

Coal fly ash, the solid waste of a coal-fired power plant, can not only pollute the groundwater system, but also can generate atmospheric pollution caused by Dust. The sintered ceramsites made from coal fly ash, small amount of clay and other admixtures were tested and used in wastewater nutrient pollution control (phosphate removal), which is a new way of fly ash resourcization. As for fly ash, the current research mainly focuses on the preparation and removal of heavy metal ions and oil from wastewater, and the fly ash ceramsite is rarely used for enhanced removal of phosphate from wastewater in ecological pollution control engineering and Biological Aerated Filter.The new sintered ceramsites were made from coal fly ash adopting sintering method, the best recipe and sintering conditions of fly ash ceramsite were selected through the design of single factor experiment and the orthogonal experiment, with specific surface area and bulk density as the measure index simultaneously.X-ray diffraction (XRD) and scanning electronic microscope (SEM) were applied to measure the fly ash ceramsite compared with normal ceramsites. Besides, the ceramsite is used for removal of phosphate on simulate the effluent of a secondary treatment process of a wastewater treatment plant, discussing the influence of initial concentration of phosphate, usage of ceramsite,reaction temperature and pH on the removal effects. In addition, the desorption experiment of adsorption saturation ceramsite was carried on, discussing synchronously the influence of desorbent,concentration of desorbent and pH on the desorption effects.The results show that specific surface area was high under the best material rate of fly ash at50g, bentonite at35g, quick lime at12g, sodium silicate at5g, and the optimal sintering condition of sintering temperature at1150℃, sintering time at45min, preheated temperature at400℃preheating time at25min. Results also proved that the remaining concentration of phosphate was less than0.5mg/Lunder the pH4-10, and the dosage of2g/L. The phosphate adsorption is a relatively slow process, and reaches equilibrium status in12hours, and the pseudo-second-order kinetic equation is suitable for the stimulation of the process. The maximum adsorption capacity of phosphate decreases with the increase of temperature, and for the temperature of15℃,25℃,35℃, the maximum adsorption capacity of fly ash ceramsites are0.7903mg/g,0.7426mg/g,0.6111mg/g respectively. The phosphate adsorbed by fly ash ceramsites could be desorbed, and the desorption rate was about70%when the concentration of stripping liquid NaOH was2.0mg/L...