Abstract
Due to the global shortage of phosphate ore, sewage sludge is an important resource for P recovery. This study aims to investigate how P was migrated and transformed during the microwave hydrothermal (MHT) process of sewage sludge. The effects of MHT and hydrothermal (HT) conversion were compared. The results reveals that there were no significant differences on the P distribution and speciation changes between the HT and MHT products, especially under high hydrothermal temperature. Ortho-P/Pyro-P was the dominant P form in the hydrothermal solid products, and high temperature promoted the transformation of C-O-P to Ortho-P/Pyro-P. The analysis of X-ray absorption near edge structure (XANES) shows that Ca5(PO4)3OH was formed after the hydrothermal processes. The relative abundance of Ca-P decreased first and then increased with increasing hydrothermal temperature. Moderate MHT temperature (170 °C) and holding time (30–60 min) promoted the transformation of P to the liquid products. Generally, the effect of MHT temperature was more significant than that of heating type and holding time on the variations of P distribution and speciations.
Original language | English |
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Article number | 152801 |
Journal | Science of the Total Environment |
Volume | 815 |
Early online date | 2 Jan 2022 |
DOIs | |
Publication status | Published - 1 Apr 2022 |
Bibliographical note
Funding Information:We acknowledge the financial support provided by: Shanghai Sailing Program ( 21YF1401700 ). We also thank the staffs of 4B7A beamline of Beijing Synchrotron Radiation Facility for the data of P K-edge XANES.
Publisher Copyright:
© 2022 Elsevier B.V.
Keywords
- Hydrothermal conversion
- Microwave hydrothermal conversion
- Phosphorus
- Sewage sludge
- X-ray absorption near edge structure