Modified Red Muds and Slag Based Hydraulic Binders for Zn Removal: A Matrix-Spiking Approach Applied on Clayey Sediments

Dredging sediments can be implemented as primary resources in several civil engineering applications, on the condition that release of anthropogenic compounds meets environmental requirements. The remediation sedimentary wastes constitutes therefore, a key step before valorization consideration circular economy schemes. This study focused Zn removal from clayey river dredged northern France (Lille, Saint-Omer and Aire-Sur-La Lys) using Thermo-Evolved Red Mud (TERM) Slag Based Hydraulic Binder (SBHB). first consisted investigating Zn-trapping mechanisms prior to TERM SBHB application Zn-stabilizers. Results underlined poorer metal retention within most organic sediment (high fatty acids polycyclic aromatic molecules concentrations), emphasizing minor role fraction typology during Zn-trapping. pollutant displayed its best binding yields with highest interstitial pH specific areas, which stressed out preponderant influence alkalinization ability particles size distribution. In second step, spiked were treated SBHB, resulted substantial lowering at 12% stabilizer/sediment ratio. Even though content was not preeminent trapping, it appeared here influential delays efficiencies observed for endowed sediment. Two preferential geochemical pathways adopted operations significant promotive roles basic background pH. Indeed, mainly sorptive involving exchanges Ca Mg ions, whereas onto principally achieved through precipitation phenomena.