The developed sorbent materials are shaped into granulates enabling their application in column set-ups with high hydraulic conductivity, easily replaceable and safe. Granular sorbents will be produced at VITO and sent for application testing at the Indian demonstration site. The composition of the designed sorbents will be adapted to the specific conditions of the Indian test-cases (considering relevant concentrations and possible competitive ions).
However, the high sorption capacity, low cost production and regeneration abilities will be present as well. In such a configuration the proposed technology follows the removal-recovery-reuse approach in which the wastewater purification (by sorption onto the granulated material), metal (Cr) and/or nutrient (P) recovery or removal (by desorption) is concomitant with a sorbent regeneration step allowing its reuse in a new wastewater purification step and the recovery of the valuable metals and nutrients.
Requirements for a good sorption material:
- High loading capacity and (controlled) selectivity (material property) and regenerability
- Good permeability (shape property)
- applicable in column set-ups
- improved mass transfer
- low-pressure drops
Results from previous projects
Horizon 2020 project CHROMIC (2016-ongoing)
This project conducted lab tests for selective recovery of chromates and vanadates from hydrometallurgical streams. The focus of this project is on selective adsorption and regeneration of sorbents.
The sorbents are synthetic clay-based powders and granulates.
Results: the sorbent sorption capacity is up to 60mg Cr6+/g. An increase of pH leads to reduced sorption capacity and the presence of carbonates may inhibit the sorption process. The optimization of sorbent regeneration is ongoing.
FWO Vlaanderen project 'Regenerable sorbent materials for aqueous waste streams' (2014-2017)
This project conducted lab tests for selective recovery of PO43- from aqueous stream with focus on selective adsorption and regeneration of sorbents. The sorbents are synthetic clay-based powders and granulates.
Results: sorbent sorption capacity up to 60mgPO43-/g, presence of carbonates may inhibit the sorption process, while P is adsorbed preferentially over Cl, NO32- or SO42-
Link to test reports: E.M. Seftel, B. Michielsen et al., Appl. Clay Sci. 165 (2018) 234-246
Interreg North Sea Region Nuredrain: Nutrients Removal and Recovery from Drainage Water (2017-2020)
This project performs lab tests for removal recovery of PO43- from aqueous streams with focus on adsorption of phosphate at different concentrations (0.5, 5, 25 ppm). The sorbents are: synthetic clay-based powders and granulates.
It involves one long-term column test of 200 days at low concentration (0.5 ppm).
The results: sorbent sorption capacity up to 15mgPO43-/g, fast kinetics (at influent concentration of 25mgPO43-/L).