Sorption properties of groundwater treatment residuals containing iron oxides
[ 1 ] Instytut Inżynierii Środowiska i Instalacji Budowlanych, Wydział Inżynierii Środowiska i Energetyki, Politechnika Poznańska | [ P ] employee
2023
scientific article
english
- Heavy metals
- Water pollution
- Water treatment sludge
- Water treatment residuals
- Adsorption capacity
- Sorption mechanism
EN Drinking water treatment produces groundwater treatment residuals (GWTRs), which can be used as mineral sorbents. GWTRs, sometimes referred to as water treatment sludge or waterworks sludge, are by-products produced by drinking water treatment plants. Their disposal is problematic and costly due to environmental constraints and has provided the impetus for research into their reuse as mineral sorbents. The main constituents of the sludge are iron and manganese oxyhydroxides, with calcium carbonate and detrital quartz (Q) in minor amounts. In this study, we investigated the sorption capacity of GWTRs toward Cd(II), Cu(II), Pb(II), Zn(II), and Cr(III), determining the effects of contact time, temperature, initial metal concentration, and pH on metal sorption efficiency. GTWRs are very effective metal sorbents, sorbing from tens to up to 230 g of metal/kg of sorbent, depending on the metal. Optimal conditions for sorption are pH 5–8, a reaction time of 4–5 h, and temperature 298 K. Investigations of the material after sorption by X-ray diffraction (XRD), infrared spectroscopy (FTIR), photoelectron spectroscopy (XPS), scanning electron microscopy with an energy dispersive spectrometer (SEM-EDS) have provided insight into the nature of the interaction of metals with GWTRs and described the reaction mechanism. Metals are removed from the solution through the processes of inner-sphere adsorption on the surface of the precipitate, coprecipitation with iron compounds and incorporation into the ferrihydrite (Fh) structure or precipitation in the form of their mineral phases, such as carbonates, metal oxides or hydroxides. The results obtained from the experiments show that GWTRs effectively remove metal cations from aqueous solutions and can be used as sorbents for pollutants from wastewater or liquid industrial waste. The next step should be to test the ability against anionic forms of metals and organic compounds.
13.06.2023
110342-1 - 110342-14
Article Number: 110342
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