The fine fraction of granular ferric hydroxide (MyGFH, < 0.3 mm) is a promising adsorbent for the removal of heavy metals and phosphate, but properties of MyGFH were hitherto not known. The present study aimed at characterizing MyGFH regarding its physical and chemical properties and at evaluating methods for the conditioning of fixed-bed filters in order to develop a process that combines filtration and adsorption. Conditioning was done at different pH levels and for different particle sizes. Anthracite, coke, pumice and sand were studied as potential carrier materials. A method for the evaluation of the homogeneity of the iron hydroxide particle distribution on pumice filter grains using picture analysis was developed. Pre-washed pumice (pH 8.5) proved to lead to high embedment and a homogeneous distribution of MyGFH. Filter runs with phosphate (2 mg/L P) showed similar breakthrough curves for the embedded fine fraction adsorbent and for conventional GFH. © 2018 by the authors.
Vanadium 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).
The use of micro-sized iron hydroxide adsorbents in mixed reactors is a promising technique for the removal of inorganic contaminants from wastewater within minutes of contact time. This study focusses on phosphate adsorption onto fine fraction granular ferric hydroxide (nGFH) and iron oxy(hydr)oxide agglomerates (IOAs) in a reactor with submerged ultrafiltration (UF) membrane. The performance of the hybrid adsorption/UF membrane system was evaluated for various adsorbents and phosphate concentrations, residence times and concentrations of co-existing ions. The membrane was not fouled at the experimental conditions used (up to 6.3 g/L adsorbent). Phosphate loadings of 20 and 60 mg P/g Fe (36.1 and 108.3 mol P/mol Fe) were reached for nGFH and IOAs, respectively (C0(P) = 4.5 mg/L, deionized water at pH 8, C(Fe) = 0.6 g/L). A shortened residence time of 15 min in the reactor led to a decrease in final loading of 6 mg/g compared to 30 min residence time (54 mg/g compared to 60 mg/g). An extension to 60 min did not result in higher loadings. An increase in adsorbent (IOA) concentration from 0.1 to 0.3 mg/L resulted in an increase of phosphate removal (27 to 35%). Simultaneously, loadings decreased from 50 to 35 mg/g. The application of the developed process for the treatment of artificial secondary effluent resulted in an increase of 87 and 60% in treated volumes until breakthrough (50%) for nGFH and IOAs, respectively, compared to deionized water. Thus, the combined process of adsorption and particle separation using a submerged membrane can be well adjusted according to water composition, initial pollutant concentrations and desired removals. © 2019 Elsevier B.V. All rights reserved.
In order to reach 4 (micro)g l-1 vanadium in drinking water adsorption onto in-situ biogenic amorphous ferric hydroxide (AFH) is identified as robust new treatment. The evaluation of its technical feasibility and robustness was the aim of this study. As approach at pilot-scale, Fe(II) and oxygen was dosed before pilot waterworks and Fe(II) subsequently biotically oxidized and precipitated in a filter bed. The so in-situ generated biogenic AFH served as adsorbent for vanadium removal. Results show that an initial vanadium concentration of 30 (micro)g l-1 was removed to below 4 (micro)g l-1, if at least 3 mg l-1 Fe(II) were dosed, resulting in a loading of 8.7 mg V per g AFH. A vanadium concentration of 60 (micro)g l-1 with a dosage of 3 mg l-1 Fe(II) was the upper limit for sufficient removal. Vanadium removal increased with increasing pH in the technical setup, due to faster oxidation of Fe(II) in the supernatant, even though adsorption capacity of AFH decreases with increasing pH. A filtration velocity of 20 m h -1 represented the highest velocity to undercut 4 (micro)g l-1 vanadium in the effluent. By mixing Fe(II) containing groundwater with oxygen and vanadium containing water prior to an adsorption filter with AFH sufficient removal was reached, however dependent on the resulting Fe(II) concentration. © 2023 by the authors
Adsorption onto ferric hydroxide is a known method to reach very low residual phosphate concentrations. Silicate is omnipresent in surface and industrial waters and reduces the adsorption capacity of ferric hydroxides. The present article focusses on the influences of silicate concentration and contact time on the adsorption of phosphate to a micro-sized iron hydroxide adsorbent (nGFH) and fits adsorption data to multi-component adsorption isotherms. In Berlin drinking water (DOC of approx. 4 mg L-1) at pH 7.0, loadings of 24 mg g-1 P (with 3 mg L-1 initial PO43--P) and 17 mg L-1 Si (with 9 mg L-1 initial Si) were reached. In deionized water, phosphate shows a high percentage of reversible bonds to nGFH while silicate adsorption is not reversible probably due to polymerization. Depending on the initial silicate concentration, phosphate loadings are reduced by 27, 33 and 47% (for equilibrium concentrations of 1.5 mg L-1) for 9, 14 and 22 mg L-1 Si respectively. Out of eight tested multi-component adsorption models, the Extended Freundlich Model Isotherm (EFMI) describes the simultaneous adsorption of phosphate and silicate best. Thus, providing the means to predict and control phosphate removal. Longer contact times of the adsorbent with silicate prior to addition of phosphate reduce phosphate adsorption significantly. Compared to 7 days of contact with silicate (c0 = 10 mg L-1) prior to phosphate (c0 = 3 mg L-1) addition, 28 and 56 days reduce the nGFH capacity for phosphate by 21 and 43%, respectively. Quelle: https://pubs.rsc.org
Hexavalent chromium is highly toxic and elaborate technology is necessary for ensured removal during drinking water production. The present study aimed at estimating the potential of a micro-sized iron hydroxide (nGFH] adsorbent for chromate removal in competition to ions presents in drinking water. Freundlich and Langmuir models were applied to describe the adsorption behaviour. The results show a high dependency on the pH value with increasing adsorption for decreasing pH values. The adsorption capacity in deionized water (DI) at pH 7 was 5.8mg/g Cr(VI) while it decreased to 1.9mg/g Cr(VI) in Berlin drinking water (DW) at initial concentrations of 1.2mg/L. Desorption experiments showed reversible adsorption indicating ion exchange and outer sphere complexes as main removal mechanisms. Competing ions present in DW were tested for interfering effects on chromate adsorption. Bicarbonate was identified as main inhibitor of chromate adsorption. Sulfate, silicate and phosphate also decreased chromate loadings, while calcium enhanced chromate adsorption. Adsorption kinetics were highly dependent on particle size and adsorbent dose. Adsorption equilibrium was reached after 60ââą ¯min for particles smaller than 63nm, while 240 min were required for particles from 125nm to 300nm. Adsorption kinetics in single solute systems could be modelled using the homogeneous surface diffusion model (HSDM) with a surface diffusion coefficient of 4x10-14m2/s. Competitive adsorption could be modelled using simple equations dependent on time, adsorption capacity and concentrations only. © 2018 Elsevier Ltd. All rights reserved.
Die Heizkraftwerk Altenstadt GmbH und Co. KG, Triebstraße 90, 86972 Altenstadt hat die immissionsschutzrechtliche Genehmigung nach § 16 Abs. 2 BImSchG für die wesentliche Änderung des Biomasseheizkraftwerkes insbesondere durch die Erweiterung der bestehenden Brennstoffpalette um Ersatzbrennstoffe auf dem Grundstück Fl.Nr. 1964/1 der Gemarkung Altenstadt beantragt. Das Vorhaben umfasst im Wesentlichen folgende Anlagenteile, bzw. Maßnahmen: - Erweiterung der bestehenden Brennstoffpalette um den Einsatz von Ersatzbrennstoff, - Errichtung eines neuen Brennstoffbunkers für EBS als Rundbau mit einem Durchmesser von 20 m und insgesamt 4 Andockstationen für die LKW Entladung sowie eines Aufbaus zur Aufnahme der Krananlage, - Errichtung eines zum Bunker gehörenden Gewebefilters zur Abluftreinigung, - Errichtung von Luftkanälen zur Nutzung der Bunkerabluft als Verbrennungsluft für die Wirbelschichtfeuerung, inkl. Kamin zur Ableitung der gereinigten Abluft bei Stillstand der Wirbelschichtfeuerung, - Anpassung / Ergänzung der Fördertechnik, um den EBS aus dem Bunker über Zuteiler, Sichter und Förderschnecken in die Wirbelschichtfeuerung zu fördern, - Erweiterung der Rauchgasreinigungsanlage um folgende Komponenten: Zyklon zur Abscheidung von Staub aus dem Wirbelschichtfeuerung, Station zur Zudosierung von Aktivkoks vor die Gewebefilter der Rauchgasreinigung und der Siloabluftreinigung, Station zur Dosierung eines hochtemperaturstabilen Adsorbens in den Feuerraum der Wirbelschichtfeuerung, Silo zur Zwischenlagerung von Zyklonasche, Silo für hochtemperaturstabiles Adsorbens, - Änderung der SNCR-Anlage und der zugehörigen Ammoniakwasserversorgung, - Entfall der Genehmigung für den bisher noch nicht errichteten Reservekessel mit 13,04 MW zur Verfeuerung von Heizöl EL und Erdgas. Das Änderungsvorhaben betrifft eine Anlage nach Nr. 8.1.1.3 des Anhangs 1 zur 4. BImSchV und bedarf eines vereinfachten Verfahrens nach § 16 Abs. 2 Satz 3 i.V.m. § 19 BImSchG. Die Regierung von Oberbayern führt antragsgemäß ein Genehmigungsverfahren nach § 16 Abs. 2 BImSchG durch, da erhebliche nachteilige Auswirkungen durch das Vorhaben nicht zu erwarten sind und eine Umweltverträglichkeitsprüfung nicht erforderlich ist.
Recent toxicological findings and expected lower regulatory limits for chromate (hexavalent chromium, Cr(VI)) in drinking water enforce the search for practical treatment options for efficient Cr(VI) removal. Cr(VI) adsorption and chemical reduction of highly soluble Cr(VI) to much less soluble Cr(III) are the main options that have already been experimentally investigated. Granular ferric hydroxide (GFH) is an established adsorbent for different pollutants but only to a limited extent for Cr(VI). The present study aimed at enriching ferrous iron (Fe(II)) as reducing constituent in the GFH to integrate reductive capabilities and thus to enhance Cr(VI) elimination. Three different batches were prepared and analyzed with regard to elemental and mineralogical compositions in comparison to conventional GFH. Long-term column tests showed enhanced Cr(VI) elimination in the modified materials with remarkably extended run-times until breakthrough. © 2019 Elsevier B.V. All rights reserved.
Small polymer particles with a diameter of less than 5 mm called microplastics find their way into the environment from polymer debris and industrial production. Therefore a method is needed to identify and quantify microplastics in various environmental samples to generate reliable concentration values. Such concentration values, i.e. quantitative results, are necessary for an assessment of microplastic in environmental media. This was achieved by thermal extraction in thermogravimetric analysis (TGA), connected to a solid-phase adsorber. These adsorbers were subsequently analysed by thermal desorption gas chromatography mass spectrometry (TDS-GC-MS). In comparison to other chromatographic methods, like pyrolyse gas chromatography mass spectrometry (Py-GC-MS), the relatively high sample masses in TGA (about 200 times higher than used in Py-GC-MS) analysed here enable the measurement of complex matrices that are not homogenous on a small scale. Through the characteristic decomposition products known for every kind of polymer it is possible to identify and even to quantify polymer particles in various matrices. Polyethylene (PE), one of the most important representatives for microplastics, was chosen as an example for identification and quantification.Quelle: http://www.sciencedirect.com
Die CABB GmbH hat beim Landratsamt Augsburg die immissionsschutzrechtliche Genehmigung gemäß § 16 BImSchG für die wesentliche Änderung der Anlage zur Herstellung von Mono-/Trichloressigsäure (MCE/TCE-Anlage) auf ihrem Betriebsgrundstück Flur-Nrn. 2235/56-62 im Industriepark Gersthofen beantragt. Dieser Antrag umfasst folgende Maßnahmen: • die Erweiterung des vorhandenen Essigsäureanhydrid-Lagers durch Installation eines zusätzlichen Lagertanks für Essigsäureanhydrid (50 m³) und eines Adsorbers sowie • verschiedene redaktionelle Änderungen (Nachtrag einer Sumpfpumpe und einer Tauchpumpe sowie Anpassung von Aggregatbezeichnungen). Die Errichtung und der Betrieb einer Anlage zur Herstellung von Mono-/Trichloressigsäure ist der Nummer 4.2 der Anlage 1 zum UVPG zuzuordnen und in Spalte 2 mit „A“ gekennzeichnet. Für das geplante Vorhaben war deshalb im Rahmen des immissionsschutzrechtlichen Genehmigungsverfahrens vom Landratsamt Augsburg eine allgemeine Vorprüfung zur Feststellung der UVP-Pflicht entsprechend den §§ 9 Abs. 2 und 4 i.V.m. § 7 Abs. 1 UVPG durchzuführen.
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