Person: Zerelli, Sami Sofiene
Lade...
E-Mail-Adresse
Geburtsdatum
Forschungsvorhaben
Organisationseinheiten
Berufsbeschreibung
Nachname
Zerelli
Vorname
Sami Sofiene
Name
3 Ergebnisse
Suchergebnisse
Gerade angezeigt 1 - 3 von 3
Veröffentlichung Biogenic amorphous ferric hydroxide as adsorbent for vanadium removal in drinking water production(2023) Dippon-Deissler, Urs; Mahringer, Daniel; Ruhl, Aki Sebastian; Zerelli, Sami SofieneVanadium as toxic heavy metal is a drinking water relevant contaminant. However, there is a lack in treatment processes to meet regulatory requirements (e.g. 4 g l-1 in Germany). This study introduces a novel treatment process - the vanadium adsorption onto biogenic amorphous ferric hydroxide (AFH). Basic mechanisms of adsorption onto AFH are described and compared to granular ferric hydroxide (GFH). Adsorption kinetics and pH dependent isotherms in drinking and ultrapure water, parametrization via the empirical Freundlich and Langmuir models, and bond type and strength assessments via sequential extraction are presented. AFH was generated in pilot waterworks in which Fe(II) and oxygen were dosed and subsequently Fe(II) microbiologically oxidized and precipitated in the filter bed. The backwash-water was collected and used for adsorption experiments. Sequential extraction was executed with vanadium loaded AFH produced in the pilot plant. AFH is identified as alternative adsorbent to GFH with similar affinity and capacity. The isotherms cover a concentration range from 10 g l-1 to 4 mg l-1 and the Freundlich model showed a better fit with the experimental data than the Langmuir model. A bidentate mononuclear inner sphere complex is assumed for vanadium adsorption onto AFH, while a bidentate binuclear inner sphere complex is expected for GFH. Sequential extraction showed a strong bond between AFH and vanadium, which was only mobilized by the last extraction step the dissolution of iron particles. A treatment process - adsorption onto biogenic AFH - is suitable for effective vanadium removal and should be further investigated for technical implementation. © 2023 The Author(s).Veröffentlichung Entfernung von Chrom (VI) mit Reduktion, Koagulation, Filtration und biologischer Eisenoxidation (RCbF) im Pilotmaßstab(2021) Dippon-Deissler, Urs; Mahringer, Daniel; Ruhl, Aki Sebastian; Zerelli, Sami SofieneVeröffentlichung Pilot scale hexavalent chromium removal with reduction, coagulation, filtration and biological iron oxidation(2020) Dippon-Deissler, Urs; Mahringer, Daniel; Ruhl, Aki Sebastian; Zerelli, Sami SofieneCr(VI) is identified as highly toxic, therefore a far-reaching limitation of total chromium or Cr(VI) in drinking water was proposed by the Germany Environment Agency. There is a lack in efficient treatment processes to reach Cr(VI) concentrations below 1 (my)g L-1. In this study, the combination of chemical reduction, coagulation and filtration (RCF) was further developed by adding biological iron removal as filtration step (RCbF). The aim of this enhancement was to reach lower effluent concentrations and a higher robustness regarding process parameters. The effectiveness of Cr(VI) removal was investigated using two-stage pilot-scale waterworks. RCbF reaches Cr(VI) effluent concentrations below 0.5 (my)g L-1 despite variations of pH, filtration velocity, or Cr(VI) influent concentrations. Fe(II) dosage and hence molar excess of Fe(II) over Cr(VI) was identified as the key parameter for Cr(VI) removal. Low oxygen dosage for biological iron removal improved the efficiency of RCbF compared to RCF. The co-precipitation of Cr(III) and Fe(III) as solid solution in the supernatant of the filter bed was promoted by low oxygen concentrations making Cr(VI) the preferred oxidant. RCbF was shown to be a suitable treatment process for reaching a low limit value for total chromium or Cr(VI) concerning technical feasibility. © 2020 The Authors.