Study on the mechanism of copper-ammonia complex decomposition in struvite formation process and enhanced ammonia and
Cong Peng1, Liyuan Chai1, Chongjian Tang1
1Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China; Chinese National Engineering Research Centre for Control and Treatment of Heavy Metal Pollution, Changsha 410083, China.
Abstract:
Heavy metals and ammonia are difficult to remove from wastewater, as they easily combine into refractory complexes. The struvite formation method (SFM) was applied for the complex decomposition and simultaneous removal of heavy metal and ammonia. The results indicated that ammonia deprivation by SFM was the key factor leading to the decomposition of the copper-ammonia complex ion. Ammonia was separated from solution as crystalline struvite, and the copper mainly co-precipitated as copper hydroxide together with struvite. Hydrogen bonding and electrostatic attraction were considered to be the main surface interactions between struvite and copper hydroxide. Hydrogen bonding was concluded to be the key factor leading to the co-precipitation. In addition, incorporation of copper ions into the struvite crystal also occurred during the treatment process.
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