Chen Liang, Zhou Chun Hui, Zhang Hao, Tong Dong Shen, Yu Wei Hua, Yang Hui Min, Chu Mao Quan
Research Group for Advanced Materials & Sustainable Catalysis (AMSC), College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, 310014, China; Key Laboratory of High Efficient Processing of Bamboo of Zhejiang Province, China National Bamboo Research Center, Hangzhou, 310012, China.
Research Group for Advanced Materials & Sustainable Catalysis (AMSC), College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, 310014, China; Qing Yang Institute for Industrial Minerals (QYIM), Youhua Township, Qingyang County, 242804, Anhui, China; Centre for Future Materials, University of Southern Queensland, Toowoomba, QLD, 4350, Australia.
Chemosphere. 2017 Nov;187:302-310. doi: 10.1016/j.chemosphere.2017.08.065. Epub 2017 Aug 13.
The capture and reuse of NH is an ideal solution to treat NH-containing wastewater. The capture and reuse process needs to be clean and cost-effective. Currently, however, there are many obstacles, particularly in the availability, cost, and recovery of the chemical sources required. Here, we demonstrate a clean and efficient method to capture and recycle NH by a dolomite-aided struvite precipitation process. Dolomite calcined carefully in CO atmosphere was used as a Mg source to react with PO (KHPO) and NH in model wastewater (2000 mg L NH). The precipitation was performed at nMg:nNH:nPO = 1:1:1.2 and pH = 8.0 for 2 h; 89.7% of NH was recovered in the form of struvite precipitate. The competition between K and NH in the model wastewater led to the formation of K-struvite (MgKPO·6HO) and struvite (MgNHPO·6HO). The formation of K-struvite resulted in a decrease in the NH removal rate. When struvite was heated at 110 °C for 4 h, the NH release rate from the thermolysis reached 75.7%. Thermolysis readily occurred as an unstable Ca-CO-NH system formed in the mixture of MgNHPO·6HO and CaCO. The elements Mg and P that were obtained during the struvite precipitation-thermolysis-reprecipitation process can be repeatedly used. After 6 cycles, under the conditions pH = 9.0, nMg:nNH:nPO = 1:1:1 and reaction time of 2 h, up to 78.3% of NH was removed from the model wastewater.
氨氮的捕集与回用是处理含氨氮废水的理想解决方案。该捕集与回用过程需要清洁且具有成本效益。然而目前存在许多障碍，特别是在所需化学源的可用性、成本和回收方面。在此，我们展示了一种通过白云石辅助鸟粪石沉淀法来捕集和循环利用氨氮的清洁高效方法。在二氧化碳气氛中小心煅烧的白云石用作镁源，与模拟废水（2000 mg·L氨氮）中的磷酸根（磷酸二氢钾）和氨氮反应。沉淀在nMg:nNH:nPO = 1:1:1.2且pH = 8.0的条件下进行2小时；89.7%的氨氮以鸟粪石沉淀的形式回收。模拟废水中钾离子和氨氮之间的竞争导致形成钾镁磷灰石（MgKPO·6H₂O）和鸟粪石（MgNH₄PO·6H₂O）。钾镁磷灰石的形成导致氨氮去除率降低。当鸟粪石在110℃加热4小时时，热解产生的氨氮释放率达到75.7%。由于在MgNH₄PO·6H₂O和CaCO₃的混合物中形成了不稳定的Ca-CO₃-NH₃体系，热解很容易发生。在鸟粪石沉淀 - 热解 - 再沉淀过程中获得的镁和磷元素可以重复使用。经过6个循环后，在pH = 9.0、nMg:nNH:nPO = 1:1:1以及反应时间为2小时的条件下，高达78.3%的氨氮从模拟废水中被去除。
