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Your search keyword '"Gernjak, Wolfgang"' showing total 124 results
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124 results on '"Gernjak, Wolfgang"'

8. Catalytic Ozonation of Pharmaceuticals Using CeO 2 -CeTiO x -Doped Crossflow Ultrafiltration Ceramic Membranes.

Author

Tsiarta, Nikoletta, Morović, Silvia, Mandić, Vilko, Panžić, Ivana, Blažic, Roko, Ćurković, Lidija, and Gernjak, Wolfgang

Subjects
MICROPOLLUTANTS, CERIUM oxides, ORGANIC compounds removal (Sewage purification), SEWAGE disposal plants, OZONIZATION, CERAMICS, ULTRAFILTRATION
Abstract

The removal of persistent organic micropollutants (OMPs) from secondary effluent in wastewater treatment plants is critical for meeting water reuse standards. Traditional treatment methods often fail to adequately degrade these contaminants. This study explored the efficacy of a hybrid ozonation membrane filtration (HOMF) process using CeO2 and CeTiOx-doped ceramic crossflow ultrafiltration ceramic membranes for the degradation of OMPs. Hollow ceramic membranes (CM) with a 300 kDa molecular weight cut-off (MWCO) were modified to serve as substrates for catalytic nanosized metal oxides in a crossflow and inside-out operational configuration. Three types of depositions were tested: a single layer of CeO2, a single layer of CeTiOx, and a combined layer of CeO2 + CeTiOx. These catalytic nanoparticles were distributed uniformly using a solution-based method supported by vacuum infiltration to ensure high-throughput deposition. The results demonstrated successful infiltration of the metal oxides, although the yield permeability and transmembrane flow varied, following this order: pristine > CeTiOx > CeO2 > CeO2 + CeTiOx. Four OMPs were examined: two easily degraded by ozone (carbamazepine and diclofenac) and two recalcitrant (ibuprofen and pCBA). The highest OMP degradation was observed in demineralized water, particularly with the CeO2 + CeTiOx modification, suggesting O3 decomposition to hydroxyl radicals. The increased resistance in the modified membranes contributed to the adsorption phenomena. The degradation efficiency decreased in secondary effluent due to competition with the organic and inorganic load, highlighting the challenges in complex water matrices. [ABSTRACT FROM AUTHOR]

Published
2024
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45. A comparative study of supported Ti[O.sub.2] as photocatalyst in water decontamination at solar pilot plant scale

Author

Kus, Mahmut, Gernjak, Wolfgang, Ibanez, Pilar Fernandez, Rodriguez, Sixto Malato, Galvez, Julian Blanco, and Icli, Siddik

Subjects
Titanium dioxide -- Usage, Solar collectors -- Analysis, Catalysis -- Analysis, Engineering and manufacturing industries, Environmental issues
Abstract

The degradation of gallic acid and imidacloprid with supported Millennium PC500 and Degussa P25 Ti[O.sub.2] is reported. Ti[O.sub.2] particles were immobilized using a titanium solsolution and direct deposition on glass supports. The film characterization was done by x-ray diffraction, scanning electron microscopy, and atomic force microscopy, and degradation of organic compounds was monitored by high-performance liquid chromatography, total organic carbon analyzer, and ion chromatography. The experiments were performed under sunlight in compound parabolic collector plants with flat supports inside the glass tubes. Photocatalytic activity of the films was compared and identified. Although sol-gel coatings had better mechanical properties, mineralization was observed to be approximately five times slower than paste-deposited films. Photoactivity of the films decreased with silver deposition due to the nature of the organic compounds. The rate constants were calculated to be between 2 x [10.sup.-1] and 6 x [10.sup.-2] mg [m.sup.2]/kJ for organic compounds, and 6 X [10.sup.-2] and 6 x [10.sup.-3] for total organic carbon. [DOI: 10.1115/1.2210494] Keywords: photocatalysis, supported catalyst, silver deposition, sol-gel film

Published
2006

46. Applied studies in solar photocatalytic detoxification: an overview

Author

Malato, Sixto, Blanco, Julian, Vidal, Alfonso, Alarcon, Diego, Maldonado, Manuel I., Caceres, Julia, and Gernjak, Wolfgang

Subjects
Refuse and refuse disposal, Rural -- Service development, Company service development, Earth sciences, Petroleum, energy and mining industries
Abstract

The technical feasibility and performance of photocatalytic degradation of four water-soluble pesticides (diuron, imidacloprid, formetanate and methomyl) have been studied at pilot scale in two well-defined systems which are of special interest because natural-solar UV light can be used for them: heterogeneous photocatalysis with titanium dioxide and homogeneous photocatalysis by photo-Fenton. The pilot plant is made up of compound parabolic collectors specially designed for solar photocatalytic applications. The initial concentration tested with imidacloprid, formetanate and methomyl was 50 and 30 mg/l with diuron, and the catalyst concentrations were 200 mg/l and 0.05 mM with Ti[O.sub.2] and iron, respectively. Total disappearance of the parent compounds, 90% mineralisation and toxicity reduction below the threshold (E[C.sub.50]) have been attained with all pesticides tested. All these results have contributed to an evaluation of photocatalytic treatment capacity and comments on the main parameters of Ti[O.sub.2] and Fe separation from the treated water.

Published
2003

50. Long-term performance of enhanced-zero valent iron for drinking water treatment: A lab-scale study.

Author

Liu, Peng, Gernjak, Wolfgang, and Keller, Jurg

Subjects
*DRINKING water purification, *IRON removal (Water purification), *ORGANIC compounds removal (Water purification), *WATER quality, *DISSOLVED organic matter
Abstract

Former studies have shown that enhanced-zero valent iron (ZVI) could effectively remove various contaminants. The present study evaluates for the first time the long-term performance of enhanced-ZVI to remove natural organic matter (NOM), an important water quality parameter in drinking water. Lab-scale flow-through experiments showed that averagely 7–14% dissolved organic carbon (DOC) and 6–15% ultraviolet absorbance at 254 nm (UV 254 ) reduction could be achieved by enhanced-ZVI in the first 10,000 bed volumes filtration when a 0.36 or 1.8 mins empty bed contact time (EBCT) was applied. After 10,000-bed volumes, the enhanced-ZVI bed became passivated. However, sulphuric acid was able to regenerate the passivated enhanced-ZVI bed, recover the capacity of enhanced-ZVI in removing NOM, and hence make the best use of the available ZVI. The acidic rinsing solution containing dissolved iron was suitable as a supplemental source of iron for coagulation. In addition, during the long-term experiments, the biofilters following enhanced-ZVI (1.8 min EBCT) removed more NOM than biofilters without any pre-treatment. This could be explained by the formation of biodegradable organic matter (BDOC) during the enhanced-ZVI process and the precipitation of iron in the biofilters. Based on these findings, a novel water treatment train, incorporating enhanced-ZVI with periodical regeneration, biofiltration, and coagulation, was proposed and evaluated. [ABSTRACT FROM AUTHOR]

Published
2017
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