Abstract
The purpose of this study is to investigate the adsorption characteristics of granular aggregates under identical experimental conditions for potential applications in highly adsorptive concrete. In this study, industrial by-products (steel slag), lightweight aggregates (expanded silica) and bio-materials (peach shell and miscanthus) are used for phosphorus (P) removal from aqueous solutions. The effects of several parameters such as the initial concentrations of P, reaction time and pH value on adsorption capacity and efficiency of P are investigated using an IC analyzer. Results show that the phosphorus adsorption of all absorbents follows the adsorption isotherms with a varying phosphorus concentration from 5 mg/L to 700 mg/L, and the adsorption isotherms data are fitted well by Langmuir equation. The steel slag exhibits a higher P-adsorption capacity and adsorption efficiency compared to lightweight aggregates and bio-materials, with an estimated maximum adsorption capacity by steel slag of 20.4 mg/g. Moreover, the P-desorption results show that steel slag has a very low P-desorption. Heat treatment is used to increase the adsorption capacity of the miscanthus owing to the change in pore structure characteristics determined by BET. The adsorption kinetic data of the steel slag follows a pseudo-second-order model. The ICP-AES, XRD and SEM-EDS analyses show that the P-adsorption of the miscanthus and peach shell follows physical adsorption, whereas the adsorption mechanism of the steel slag can be attributed to the Ca2+ released from the steel slag, which can react with P and form a stable Ca–P precipitate. It is suggested that steel slags can function as effective adsorptive aggregate for the manufacture of highly adsorptive concrete.
| Original language | English |
|---|---|
| Article number | 123933 |
| Number of pages | 13 |
| Journal | Journal of Cleaner Production |
| Volume | 278 |
| DOIs | |
| Publication status | Published - 1 Jan 2021 |
Funding
This work is funded by the Graduate Student’s Research and Innovation Fund of Sichuan University (Grant No. 2018YJSY091 ), and the China Scholarship Council (CSC) Fund (Grant No. 201806240037 ) and Eindhoven University of Technology . The authors gratefully thank Ing. Anneke Delsing for the support with the chemical test analysis. NNRGY (The Netherlands), ENCI (The Netherlands) and TATA steel (The Netherlands) are thanked for the materials supply.
| Funders | Funder number |
|---|---|
| Eindhoven University of Technology | |
| China Scholarship Council | 201806240037 |
| Tata Steel Europe Ltd. | |
| Sichuan University | 2018YJSY091 |
Keywords
- Adsorption kinetics
- Expanded silica
- Miscanthus
- Peach shell
- Phosphorus removal
- Steel slag
