Wu H F, Wang J P, Duan E G, Feng Y F, Wan Z Y, Wu Y X, Lu Y Q
Department of Municipal Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China E-mail:
Water Sci Technol. 2019 Jun;79(12):2378-2386. doi: 10.2166/wst.2019.241.
Alum sludge is the sludge discharged from a sedimentation tank in a drinking water treatment plant when polymerized with poly-aluminum chloride (PAC). In this paper, granular alum sludge adsorbent (GASA) was manufactured using powdery alum sludge (PAS) as the raw material and methods such as gluing and pore-forming. The effects of different binders, pore-forming agents, roasting temperatures, and roasting times on the formation of GASA and its dephosphorization performance were investigated. Results showed that the optimum binder was AlCl at a mass ratio of 8%, and the best pore-forming agent was starch at a 4% dosage ratio. Meanwhile, the optimum roasting temperature and time were 500 °C and 2 hours, respectively. The specific surface area of GASA was 23.124 m/g. Scanning electron microscopy suggested that GASA's surface became rough, particles became tight, and average pore size increased, with additional pore channels. P adsorption by GASA reached 0.90 mg/g. The effluent phosphorus concentration of actual tail water decreased to 0.49 mg/L and the removal rate reached 73.5% when the GASA dosage was 20 g/L. The findings of this study are important for the further development of a low-cost adsorbent material for P removal in the future.
明矾污泥是饮用水处理厂沉淀池在与聚合氯化铝（PAC）聚合时排出的污泥。本文以粉状明矾污泥（PAS）为原料，采用粘结、造孔等方法制备了颗粒状明矾污泥吸附剂（GASA）。研究了不同粘结剂、造孔剂、焙烧温度和焙烧时间对GASA形成及其脱磷性能的影响。结果表明，最佳粘结剂为质量比8%的AlCl，最佳造孔剂为用量比4%的淀粉。同时，最佳焙烧温度和时间分别为500℃和2小时。GASA的比表面积为23.124 m/g。扫描电子显微镜显示，GASA的表面变得粗糙，颗粒变得紧密，平均孔径增大，并有额外的孔道。GASA对磷的吸附量达到0.90 mg/g。当GASA投加量为20 g/L时，实际尾水的出水磷浓度降至0.49 mg/L，去除率达到73.5%。本研究结果对未来开发低成本除磷吸附材料具有重要意义。
