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Advisor(s)
Abstract(s)
Phosphorus (P) removal from urban wastewater is increasingly relevant in the wastewater treatment sector. The
present work aims to contribute to the study of the adsorption process as a P removal technology. Biogenic
calcium carbonate from industrial eggshell waste prepared by milling and calcination was used as an adsorbent.
Batch adsorption experiments were conducted using real wastewater with 40 mg P/L (orthophosphate), original
pH 7.33, under stirring conditions (100 rpm). The adsorbent was characterized using SEM-EDS, XRD, and FTIRATR
before and after adsorption. From an initial screening of calcination times (15, 30, 60, and 120 min) and
considering a balance between P removal and energy saving, the adsorbent selected was eggshell calcined at
700 ◦C for 60 min. The Langmuir isotherms describe the experimental data with a maximum adsorption capacity
of 4.57 mg P/g at 25 ◦C. The adsorption process reached equilibrium within 120 min for different dosages (5, 10,
and 20 g/L at 25 ◦C). Batch experiments showed that SO42 , at a concentration of 2689 mg/L reduced the P
adsorption selectivity for dosages ≤10 g/L at 25 ◦C. Characterization of the loaded adsorbent shows that P
adsorption from real wastewater is mostly electrostatic attraction, with the contribution of ligand exchange and
microprecipitation. The adsorption capacity and behavior of the selected adsorbent seem promising for P
removal from urban wastewater compared with other low-cost adsorbents.
Description
Keywords
Eggshell Equilibrium isotherms Kinetics Phosphate Wastewater treatment
Pedagogical Context
Citation
Santos, A.F., Lopes, D.V., Alvarenga, P., Gando-Ferreira, L.M., Quina, M.J. (2024). Phosphorus removal from urban wastewater through adsorption using biogenic calcium carbonate, Journal of Environmental Management, 351, 119875
Publisher
Elsevier