海泡石原位生长纳米结构Mg(OH)_2及MAP结晶法同步回收废水中的氮磷

In-situ growth of nano-sized Mg(OH)_2 on sepiolite and its application on simultaneous removal of nutrients from waste water through MAP crystallization

采用水热法在海泡石纤维表面原位沉积纳米结构Mg(OH)_2(MSEP),以其为吸附剂同步回收废水中的氮磷;考察吸附剂投加量、溶液初始pH值、反应时间等对回收过程的影响;采用SEM、TEM、XRD、SEM-EDS、FTIR等手段对回收沉泥的理化特征进行表征。结果表明,当MSEP添加量为1. 0g/L、反应时间为40min、溶液初始pH值为7.5时,样品对氨氮、磷酸盐的平衡吸附量分别达62. 52、115. 68mg/g;MSEP对废水中氮磷的回收过程符合准二级动力学模型(R^2> 0.99);沉泥理化表征证明MSEP对废水中氮磷的主要回收机制为磷酸铵镁结晶法。

Brucite nanoflakes were deposited in-situ on sepiolite fiber(MSEP) via a hydrothermal method,and were applied for simultaneous recovery of phosphate and ammonium from waste water. Different reaction conditions including adsorbent dosage,solution pH and contact time were investigated. Precipitates collected were characterized by SEM,TEM,XRD,SEM-EDS and FTIR. The results show that MSEP exhibits a high equilibrium adsorption capacity reaching 62.52mg/g of ammonium and 115. 68 mg/g of phosphate at adsorbent dosage of 1.0g/L,initial pH of 7.5 and contact time of40 min. The MSEP adsorption kinetics follows the pseudo-second-order kinetic model(R^2> 0.99). Characterization of precipitates reveals the main mechanism of phosphate and ammonium recovery by MSEP is magnesium ammonium phosphate crystallization.