Turbidity Changes during Carbamazepine Oxidation by Photo-Fenton

The objective of this study is to evaluate the turbidity generated during the Fenton photo-reaction applied to the oxidation of waters containing carbamazepine as a function of factors such as pH, H2O2 concentration and catalyst dosage. The results let establish the degradation pathways and the main decomposition byproducts. It is found that the pH affects the turbidity of the water. Working between pH = 2.0 and 2.5, the turbidity is under 1 NTU due to the fact that iron, added as a catalyst, is in the form of a ferrous ion. Operating at pH values above 3.0, the iron species in their oxidized state (mainly ferric hydroxide in suspension) would cause turbidity. The contribution of these ferric species is a function of the concentration of iron added to the process, verifying that the turbidity increases linearly according to a ratio of 0.616 NTU L/mg Fe. Performing with oxidant concentrations at (H2O2) = 2.0 mM, the turbidity undergoes a strong increase until reaching values around 98 NTU in the steady state. High turbidity levels can be originated by the formation of coordination complexes, consisting of the union of three molecules containing substituted carboxylic groups (BaQD), which act as ligands towards an iron atom with Fe3+ oxidation state.

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Arsenic removal by ferric-chloride coagulation – effect of phosphate, bicarbonate and silicate

Water Science & Technology ◽

10.2166/wst.2011.419 ◽

2011 ◽

Vol 64 (5) ◽

pp. 1046-1055 ◽

Cited By ~ 11

Author(s):

Dóra Laky ◽

István Licskó

Keyword(s):

Adverse Effect ◽

Arsenic Removal ◽

Linear Regression Analysis ◽

Arsenic Concentration ◽

Ferric Hydroxide ◽

Multiple Linear Regression Analysis ◽

Ph Values ◽

Robust Model ◽

Coagulant Dosage ◽

Negative Effect

Jar tests with synthetic water were carried out in order to investigate the effect of phosphate, bicarbonate and silicate on arsenic removal efficiency by in-situ formed ferric hydroxide. Above 12 mg C/L inorganic carbon concentration, the adverse effect of bicarbonate was definite, and resulted in higher remaining arsenic concentration. At all pH values (7.5–7.8) and coagulant dosages (0.84–3.00 mg/L Fe) tested, the negative effect of phosphate on arsenic removal was also evident. In the presence of silicate small ferric-hydroxide colloids were formed, which were able to go through the 0.45 μm pore-size membrane. Compared to silicate-free systems, 2.5–3.5 times higher coagulant dose was needed to achieve the target arsenic concentration in the presence of 14–23 mg/L Si. At higher pH values the adverse effect of silicate was even more significant. All data were merged and multiple linear regression analysis was carried out in order to build up a robust model to predict the residual arsenic concentration if the raw water contains 50–60 μg/L initial arsenic concentration. The estimation was based on the following variables: PO4-P concentration, final pH, Si concentration, Fe(III) dose. The most important influencing factors proved to be the silicate concentration and applied coagulant dosage.

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Batch studies of phosphonate adsorption on granular ferric hydroxides

Water Science & Technology ◽

10.2166/wst.2020.055 ◽

2020 ◽

Vol 81 (1) ◽

pp. 10-20 ◽

Cited By ~ 1

Author(s):

T. Reinhardt ◽

M. Gómez Elordi ◽

R. Minke ◽

H. Schönberger ◽

E. Rott

Keyword(s):

Contact Time ◽

Room Temperature ◽

Adsorption Process ◽

Ferric Hydroxide ◽

Batch Experiments ◽

Batch Studies ◽

Influence Of Temperature ◽

Ph Values ◽

Adsorption Desorption ◽

Granular Ferric Hydroxide

Abstract Phosphonates are widely used in various industries. It is desirable to remove them before discharging phosphonate-containing wastewater. This study describes a large number of batch experiments with adsorbents that are likely suitable for the removal of phosphonates. For this, adsorption isotherms for four different granular ferric hydroxide (GFH) adsorbents were determined at different pH values in order to identify the best performing material. Additionally, the influence of temperature was studied for this GFH. A maximum loading for nitrilotrimethylphosphonic acid (NTMP) was found to be ∼12 mg P/g with an initial concentration of 1 mg/L NTMP-P and a contact time of 7 days at room temperature. Then, the adsorption of six different phosphonates was investigated as a function of pH. It was shown that GFH could be used to remove all investigated phosphonates from water and, with an increasing pH, the adsorption capacity decreased for all six phosphonates. Finally, five adsorption–desorption cycles were carried out to check the suitability of the material for multiple re-use. Even after five cycles, the adsorption process still performed well.

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Heterogeneous Photocatalytic Discoloration/Degradation of Rhodamine B with H2O2 and Spinel Copper Ferrite Magnetic Nanoparticles

Australian Journal of Chemistry ◽

10.1071/ch13435 ◽

2014 ◽

Vol 67 (4) ◽

pp. 609 ◽

Cited By ~ 11

Author(s):

Ariadna Flores ◽

Karina Nesprias ◽

Paula Vitale ◽

Julia Tasca ◽

Araceli Lavat ◽

...

Keyword(s):

Rhodamine B ◽

Uv Light ◽

Synergetic Effect ◽

Copper Ferrite ◽

H2o2 Concentration ◽

Experimental Conditions ◽

Secondary Pollution ◽

Uv Light Irradiation ◽

Degradation Reaction ◽

Catalyst Dosage

The discoloration/degradation of the artificial dye Rhodamine B (RhB) was investigated using advanced oxidation technologies. Aqueous solutions of RhB containing spinel copper ferrites (CuFe2O4) as a heterogeneous catalyst were exposed to UV irradiation/hydrogen peroxide. Under these experimental conditions the discoloration/degradation of RhB is strongly promoted by copper ferrites, reaching 95 % discoloration of the dye in 10 min and 97 % degradation in 200 min. The influence of the catalyst amount, H2O2 concentration, light source, and UV light intensity were studied. Optimum concentrations of H2O2 and catalyst dosage were found for the RhB degradation reaction. The catalyst had high magnetic sensitivity under an external magnetic field, which allowed its magnetic separation from water avoiding secondary pollution processes, and its recycling. A markedly synergetic effect of spinel copper ferrite and UV light irradiation was observed for the RhB discoloration/degradation with H2O2 as a green oxidant.

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Influence of particle properties on iron flocculation

Water Science & Technology Water Supply ◽

10.2166/ws.2017.216 ◽

2017 ◽

Vol 18 (5) ◽

pp. 1617-1624

Author(s):

D. J. de Ridder ◽

D. van Halem

Keyword(s):

Positive Charge ◽

Water Phase ◽

Significant Delay ◽

Iron Species ◽

Particle Properties ◽

Charged Species ◽

Ph Values ◽

Ph Range ◽

Positively Charged ◽

Charge Interactions

Abstract In this study, the importance of charge interactions during flocculation of Fe3+ in the presence of particles and anions/cations at various pH values was investigated. SiO2, (s) and ZnO(s) were dosed as particles to promote charge interactions and/or serve as a nucleus to accelerate floc formation. In the pH range 6–9, SiO2, (s) is negatively charged, while ZnO(s) carries a positive charge. Ca2+ and HPO42− were selected to investigate charge interactions in the water phase. A significant delay in floc growth due to charge repulsion between negatively charged iron species was observed at pHini 9. For positively charged species at pHini 6, a delay in floc growth was observed as well, but to a lesser degree. These effects could be neutralized by either dosing (positively charged) ZnO(s) or Ca2+ at pHini 9, or (negatively charged) SiO2, (s) at pHini 6. The addition of phosphate did not hinder floc growth at pHini 6. While phosphate completely inhibited floc growth at pHini 7–9 in the presence of negatively charged SiO2, (s), the presence of positively charged ZnO(s) partly neutralized the detrimental influence of phosphate on floc growth. Similarly, dosing Ca2+ partly neutralized the effect of phosphate.

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Precipitation of Ferric Phosphate in Activated Sludge: A Chemical Model and Its Verification

Water Science & Technology ◽

10.2166/wst.1989.0235 ◽

1989 ◽

Vol 21 (4-5) ◽

pp. 325-337 ◽

Cited By ~ 43

Author(s):

Cornelia Luedecke ◽

Slawomir W. Hermanowicz ◽

David Jenkins

Keyword(s):

Activated Sludge ◽

Adsorption Mechanism ◽

Solubility Product ◽

Ferric Hydroxide ◽

Phosphate Removal ◽

Chemical Model ◽

Additional Mechanism ◽

Ph Values ◽

Ferric Phosphate ◽

Proposed Model

A chemical model of ferric phosphate precipitation was developed describing ferric hydroxy-phosphate precipitation either alone or together with ferric hydroxide. Conditions for formation of one or two precipitates are examined. The model also incorporates an additional mechanism for phosphate removal through adsorption of PO43− ions on the precipitate. Experimental verification of the proposed model was carried out in lab-scale batch and continuous activated sludge units fed with municipal primary effluent and at five pH values in the range of 6.5 to 8.0. Solubility of ferric phosphate in the activated sludge system was significantly different from that reported in the literature for distilled water systems and was pH-dependent with a minimum at pH of approx. 7.0. It is proposed that the composition of precipitating ferric hydroxy-phosphate can be represented by the empirical formula Fe2.5PO4(OH)4.5. Corresponding solubility product was estimated at pKsp=96.7. The adsorption mechanism has an important effect on total phosphate removal, especially at low residual phosphate concentrations.

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Heterogeneous catalytic ozonation of 2-chlorophenol queous solution with alumina as a catalyst

Water Science & Technology ◽

10.2166/wst.2001.0092 ◽

2001 ◽

Vol 43 (2) ◽

pp. 213-220 ◽

Cited By ~ 35

Author(s):

C.H. Ni ◽

J.N. Chen

Keyword(s):

Catalytic Ozonation ◽

Solid Catalyst ◽

Heterogeneous Catalytic ◽

Ph Values ◽

Catalyst Dosage ◽

Reaction Constants ◽

Kinetics Of

Heterogenous catalytic ozonation of 2-chlorophenol (2-CP) in the presence of γ-alumina as a solid catalyst has been investigated in this research. It showed that the rate for degradation of TOC could increase from 21% to 43%. The pseudo-first reaction constants of 2-CP could increase from 0.8688 min-1 to 0.1270, increasing by approximately 40%. At the same time, the consumption of ozone was only half that of ozone alone. This research also explored the effects of the catalyst dosage, pH values and removal kinetics of 2-CP. In addition, three consecutive running with the same catalyst revealed insignificant reduction of the activity. Furthermore, the elimination of toxicity was evaluated by Microtox® analysis. The detoxification was more stable and with good results.

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Glycine–Nitrate Combustion Synthesis of Cu-Based Nanoparticles for NP9EO Degradation Applications

Catalysts ◽

10.3390/catal10091061 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1061

Author(s):

Hsu-Hui Cheng ◽

Shiao-Shing Chen ◽

Hui-Ming Liu ◽

Liang-Wei Jang ◽

Shu-Yuan Chang

Keyword(s):

Photocatalytic Activity ◽

Photoelectron Spectroscopy ◽

Catalyst Activity ◽

Particle Surface ◽

Operating Conditions ◽

Optimum Operating ◽

H2o2 Concentration ◽

Particle Surface Area ◽

X Ray ◽

Catalyst Dosage

Copper-based nanoparticles were synthesized using the glycine–nitrate process (GNP) by using copper nitrate trihydrate [Cu(NO3)2·3H2O] as the main starting material, and glycine [C2H5NO2] as the complexing and incendiary agent. The as-prepared powders were characterized through X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy analysis. Using Cu(NO3)2·3H2O as the oxidizer (N) and glycine as fuel (G), we obtained CuO, mixed-valence copper oxides (CuO + Cu2O, G/N = 0.3–0.5), and metallic Cu (G/N = 0.7). The XRD and BET results indicated that increasing the glycine concentration (G/N = 0.7) and reducing the particle surface area increased the yield of metallic Cu. The effects of varying reaction parameters, such as catalyst activity, catalyst dosage, and H2O2 concentration on nonylphenol-9-polyethoxylate (NP9EO) degradation, were assessed. With a copper-based catalyst in a heterogeneous system, the NP9EO and total organic carbon removal efficiencies were 83.1% and 70.6%, respectively, under optimum operating conditions (pH, 6.0; catalyst dosage, 0.3 g/L; H2O2 concentration, 0.05 mM). The results suggest that the removal efficiency increased with an increase in H2O2 concentration but decreased when the H2O2 concentration exceeded 0.05 mM. Furthermore, the trend of photocatalytic activity was as follows: G/N = 0.5 > G/N = 0.7 > G/N = 0.3. The G/N = 0.5 catalysts showed the highest photocatalytic activity and resulted in 94.6% NP9EO degradation in 600 min.

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Uranium Mineral – Groundwater Equilibration at the Palmottu Natural Analogue Study Site, Finland

MRS Proceedings ◽

10.1557/proc-294-497 ◽

1992 ◽

Vol 294 ◽

Cited By ~ 3

Author(s):

Lasse Ahonen ◽

H. Ervanne ◽

T. Ruskeeniemi ◽

T. Jaakkola ◽

R. Blomqvist

Keyword(s):

Narrow Range ◽

Ferric Hydroxide ◽

Oxidation States ◽

Water Type ◽

Uranium Mineral ◽

Natural Analogue ◽

Ph Values ◽

Analogue Study ◽

Uranium Oxidation ◽

Good Consistency

ABSTRACTThe redox-potential, pH, chemical composition of fracture waters, and uraninite alteration associated with the Palmottu uranium mineralization, have been studied. The data have been interpreted by means of thermodynamic calculations. The results indicate equilibrium between uraninite, ferric hydroxide and groundwater in the bedrock of the study site. Partially oxidized uraninite (UO2.33) and ferric hydroxide are in equilibrium with the fresh, slightly acidic and oxidized water type, while primary uraninite is stable with deeper waters that have a higher pH and lower Eh. Measured Eh-pH values of groundwater cluster within a relatively narrow range indicating buffering by heterogenous redox-processes. A good consistency between measured Eh and analyzed uranium oxidation states was observed.

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