Mixed precipitation characteristics of Cu in high alkaline waste by CO_2 bubbling
WANG Lei;CHEN Qi;GAO He-hua;XING Guang-cheng;Key Laboratory of Clean Energy of Liaoning Province,Shenyang Aerospace University;
The change of wastewater p H value,the characteristics of formation of insoluble metal hydroxide precipitate and metal Carbonate precipitate,and the adsorption and coprecipitation characteristics of heavy metal ions with the hydrated oxides of iron and aluminium and calcite have been investigated by bubbling of CO2. After CO2 was gradually bubbled to the high alkaline waste,the value of waste p H was measured. Meanwhile,the metal ion in waste water was measured by Inductively Coupled Plasma( ICP) and the precipitated sediments,principally Ca CO3,were inspected by X-ray powder diffraction( XRD). The complicated precipitation characteristics of Cu in high alkaline wastewater by addition of CO2 was simulated by PHREEQC. The results showed that solution p H value was effectively neutralized and the amount of Cu was significantly decreased after CO2 was gradually bubbled to the high alkaline waste. The sediment primarily consisted of Ca CO3 and the precipitate contains Cu. At high p H value,the sediment of Cu was mainly hydroxide precipitate. As more CO2 was bubbled in,Coprecipitation with Ca CO3 was produced. The adsorption of Cu on Fe and Al colloid and co-precipitation with Ca CO3 was investigated in detail. Iron and aluminum hydroxide can adsorb copper,but the effect is not obvious because the amount of colloid is low.