摘要：

粉煤灰已成为我国排放量较大的工业固废之一，富含二氧化硅、氧化铝和氧化铁，是制备聚硅酸铝铁（PSAF）的理想原料，其资源化利用具有重要的环境和经济效益。通过正交实验优化了粉煤灰制备PSAF的条件，并将最优条件下制备的PSAF基液负载于粉煤灰上，制备新型粉煤灰负载PSAF絮凝剂，评估了其对低浓度生活污水的处理效能及经济性。研究表明，PSAF絮凝剂的最佳制备条件为碱灰比n（Na₂CO₃）∶n（SiO₂）=1∶2、煅烧温度900 ℃、盐酸浓度2 mol/L、酸浸温度70 ℃。粉煤灰负载PSAF絮凝剂投加614.8 mg/L处理低浓度生活污水时，污水COD去除率、浊度去除率以及出水透光率最高，分别可达75.9%、97.0%和98.3%。与未负载产品及市购PSAF絮凝剂相比，粉煤灰负载PSAF絮凝剂用量少，COD去除效果好。采用X射线衍射仪（XRD）、傅里叶红外光谱仪（FT-IR）、扫描电镜（SEM）等分析粉煤灰负载PSAF絮凝剂的晶体结构、形貌及表面基团，以阐明其混凝机理。结果表明，该新型絮凝剂在混凝过程中表现出高效的电中和、吸附架桥和网捕卷扫性能。粉煤灰负载PSAF絮凝剂固体生产成本较市售PSAF絮凝剂节约1 000~1 500元/t，具有良好的实用价值和经济效益。

关键词: 粉煤灰, 聚硅酸铝铁絮凝剂, 混凝, 低污染废水

Abstract:

Coal Ash has become one of the largest industrial solid wastes in China, due to its content of silicon dioxide,alumina and metal oxides, it serves as an ideal raw material for preparing polysilicate aluminum ferric (PSAF) with significant environmental and economic benefits for waste utilization. Through orthogonal experiments, the optimal preparation conditions for PSAF were determined. The PSAF base liquid prepared under optimal conditions was then mixed with coal ash to produce an innovative coal ash-loaded PSAF flocculant, whose treatment efficiency and economic performance for low-concentration domestic wastewater were evaluated. The study revealed that the optimal preparation conditions for the PSAF flocculant were as follows: alkali-to-ash ratio n(Na₂CO₃)∶n(SiO₂)=1∶2, calcination temperature of 900 ℃, hydrochloric acid concentration of 2 mol/L, and acid leaching temperature of 70 ℃. When treating low-concentration domestic wastewater with a dosage of 614.8 mg/L of the coal ash-loaded PSAF flocculant, the maximum removal rates of COD, turbidity, and effluent light transmittance reached 75.9%, 97.0%, and 98.3%, respectively. Compared to unloaded products and commercially available PSAF flocculants, the coal ash-loaded PSAF flocculant required a smaller dosage and demonstrated superior COD removal efficiency. The crystal structure, morphology, and surface functional groups of the flocculant were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) to elucidate the coagulation mechanism. The results indicated that the novel flocculant exhibited more efficient charge neutralization, adsorption bridging, and sweep flocculation. The solid production cost of the coal ash-loaded PSAF flocculant was 1 000-1 500 yuan/t lower than that of commercially available PSAF flocculants, highlighting its strong practical value and significant economic benefits.

Key words: coal ash, polysilicate aluminum ferric flocculant, coagulation, low-concentration wastewater

中图分类号: 

• X703