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| Performance and Mechanism of Zn2+, Cu2+ and Pb2+ Adsorption by Surplus Sludge Lysed Ash Ceramsite in Acid Mine Drainage |
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Received:March 28, 2023
Revised:April 03, 2023
Accepted:April 04, 2023
Published Online:July 10, 2023
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| DOI：doi：10.3969/j.issn.1007-7545.2023.08.019 |
| KeyWord:surplus sludge; porous ceramic; acid mine drainage; heavy metal adsorption |
| Author | Institution |
| WU Quan-jia |
中国矿业大学环境与测绘学院 |
| WANG Duo |
中国矿业大学环境与测绘学院 |
| YE Tao |
中国矿业大学环境与测绘学院 |
| WANG Jiang-meng |
中国矿业大学环境与测绘学院 |
| LI Xiang-dong |
中国矿业大学环境与测绘学院 |
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| Abstract: |
| The porous ceramsite were prepared by using residual sludge lysed ash as main raw material, mixed in mass ratio of residual sludge lysed ash, bentonite and starch of 6︰3︰1, granulated, cooked, dried, and finally calcined at 1 050 ℃ for 60 minutes under nitrogen atmosphere. SEM-EDS and XRD were used to characterize the micro morphology, elemental changes, and crystal structure of ceramsite before and after adsorption of Zn2+, Cu2+, and Pb2+ in AMD. The results show that the prepared ceramsite has a rough surface and a lot of porosity structures. When the dosage of ceramsite is 3 g, initial pH value is 3.2, and reaction time is 24 h, the removal rate of Zn2+, Cu2+, and Pb2+ from the prepared residual sludge pyrolysis ash ceramsite is 99.20%, 85.10%, and 96.27%, respectively. When the initial pH is neutral, the adsorption effect of ceramsite is better than that of acid conditions. The adsorption processes of Cu2+ and Pb2+ are in accordance with the quasi-secondary kinetic model, with ion exchange as the dominant process; for Zn2+, both the quasi-first and quasi-secondary kinetic models are well fitted, with physical and chemical adsorption playing equally important roles. The adsorption processes of ceramsite are in accordance with the Freundlich isothermal model. The adsorption of Cu2+ mainly occurs at heterogeneous active sites, while the adsorption of Zn2+ and Pb2+ could occur in both homogeneous monolayer and heterogeneous active sites. The preparation of porous ceramsite from residual sludge pyrolysis ash can not only be applied to the treatment of heavy metal ions in AMD, but also solve the problem of sludge disposal, achieving the goal of treating pollution with waste. |
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