科研之友
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摘要
BACKGROUND: Copper-ammonia-containing wastewater is widely generated in various industrial sectors, such as semiconductor production, printed circuit board (PCB) manufacturing, surface finishing, and electroplating processes. Three chemical precipitation methods, i.e. hydroxide precipitation, sulfide precipitation and struvite formation for treatment of chelated copper-ammonia wastewater have been comparatively evaluated. RESULTS: The conventional hydroxide precipitation method possessed the highest copper and ammonia removal at 60.5% and 9.7%, respectively. Although sulfide precipitation decomposed the copper-ammonia complex with the high copper removal of 98.5%, the ammonia removal was just 14.0%. The struvite formation method was demonstrated to be effective for enhanced simultaneous copper and ammonia removal with efficiencies of 99.9% and 98.8%, respectively. UV-vis analysis indicated that the struvite formation method also decomposed the copper-ammonia complex ion. Using XPS and XRD spectra, struvite and cupric hydroxide were shown to be formed after the addition of magnesium and phosphate (with molar ratio n(Mg:P): n(NH3-N) ranging from 1.0-1.2:1). The larger particle size of the precipitates in the struvite forming process and the enhanced settling property indicated the binding interaction between Cu(OH)(2) and struvite which enhanced the sedimentation and finally contributed to the simultaneous and highly efficient removal of copper and ammonia from the recalcitrant chelated wastewater. CONCLUSION: The struvite formation method performs far better than hydroxide precipitation and sulfide precipitation methods. Binding interaction between cupric hydroxide and struvite enhanced the performance. This study provides some guidance on application of the struvite formation method for the simultaneous removal of heavy metal and ammonia from polluted water.
- 出版日期2017-2
- 单位中南大学
