Preparation of non-sintered fly ash filter (NSFF) for ammonia nitrogen adsorption
Preparation of non-sintered fly ash filter (NSFF) for ammonia nitrogen adsorption
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DOI：
10.1080/09593330.2018.1435733
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发表时间：
2019-06
影响因子：
2.8
通讯作者：
Qing Shao;Mingming Lu;Jingchun Zhou;Zufu Zhu;Yin Song
中科院分区：
文献类型：
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作者：
Qing Shao;Mingming Lu;Jingchun Zhou;Zufu Zhu;Yin Song
摘要针对我国“以废治废，变废为宝”的目标，以城市污泥为添加剂，研制了一种非烧结粉煤灰滤料。它由70.9%的粉煤灰，7%的污水污泥，9%的水泥，7.1%的CaO，1%的NaHCO 3和5%的水玻璃溶液。混合后，加入34 g/（100 g干材料）水，然后造粒并在80 ℃下蒸汽固化16 h。NSFF的主要性能指标包括比表面积（SSA）为17.038 m2 g−1，滤料破碎率（FMBR）为2.2%，表观密度（AD）为1140 kg m−3，孔隙率为41.67%，符合中国标准CJ/T 299-2008。与同类非烧结粉煤灰陶粒产品相比，该NSFF具有较大的SSA和较低的AD。此外，NSFF的浸出毒性符合中国危险废物标准（GB5085.3-2007）。因此，NSFF作为水处理过滤介质是有效和安全的。研究了NSFF对氨氮的吸附特性。结果表明，NSFF吸附氨氮的最佳工艺参数为：NSFF投加量为5 g，初始氨氮浓度为225 mg L−1，pH为7，吸附时间为12 h，温度为30°C。在最佳条件下，NSFF对氨氮的吸附容量为4.25 mg g-1。吸附过程符合Langmuir等温式和准二级动力学模型。吸附机理包括吸附和阳离子交换。
ABSTRACT In accordance with China’s goal of ‘treating wastes with wastes, turning wastes into treasure’, a non-sintered fly ash filter (NSFF) with sewage sludge as additive was prepared. It consists of 70.9% fly ash, 7% sewage sludge, 9% cement, 7.1% CaO, 1% NaHCO3 and 5% sodium silicate solution. After mixing, 34 g/(100 g dry material) water was added, and then was granulated and steam cured under 80°C for 16 h. NSFF’s main performance indexes include specific surface area (SSA) of 17.038 m2 g−1, filter media breaking rate (FMBR) of 2.2%, apparent density (AD) of 1140 kg m−3, and porosity of 41.67%, meeting the Chinese Standard CJ/T 299-2008. This NSFF has a larger SSA and a lower AD comparing with the other similar non-sintered fly ash ceramsite products. Moreover, leaching toxicity of the NSFF has met the Chinese Standards for Hazardous Wastes (GB5085.3-2007). Therefore, the NSFF is effective and safe to use as a water treatment filter media. The NSFF’s adsorption characteristics for ammonia nitrogen was investigated. Results showed that the optimized parameters for ammonia nitrogen adsorption are as follows, NSFF dosage at 5 g, initial ammonia nitrogen concentration of 225 mg L−1, pH at 7, contact time of 12 h and temperature at 30°C. Under the optimum conditions, the adsorption capacity of NSFF for ammonia nitrogen was 4.25 mg g−1. The adsorption process can be best described by Langmuir isotherm and pseudo-second-order kinetic model. The proposed adsorption mechanism include adsorption and cation exchange.