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1

Synthesis and Characterization of Hydroxyapatite/Titania Composite and Its Application on Photocatalytic Degradation of Remazol Red B Textile Dye Under UV Irradiation

Sukarta I. Nyoman, Sastrawidana I. Dewa Ketut

Ecological Engineering & Environmental Technology

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2024

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Vol. 25, iss. 2

178--189

EN

This research was conducted to synthesize and characterize hydroxyapatite-titania (HA/TiO2) composites and test their photocatalytic degradation activity on the remazol red RB textile dye. The chemical precipitation method was utilized to produce hydroxyapatite (HA) based on the conversion of calcium carbonate presented in sea mussel shells into calcium oxide with a calcination temperature of 1000°C for 2 hours and then followed by the addition of phosphorous acid at pH medium of 11 and sintered at 700°C to obtain an HA crystal. The HA/TiO2 composite at variation weight of HA and TiO2 ratio were prepared with hydrothermal technique and characterized by the FTIR spectroscopy, X-ray diffraction, and scanning electron with energy dispersive X-ray spectroscopy. A total of 250 mL of 50 mg/L Remazol red RB dye solution was photocatalytically removed using a HA/TiO2 composite irradiated with 25 Watt UV light and using the adsorption method. Characterization results using FTIR, XRD, and SEM-EDX show that the synthesized hydroxyapatite (HA) has a degree of crystallinity of 68% with a Ca/P ratio of 1.66. The highest degradation efficiency of 250 mL of remazol red RB with a concentration of 50 mg/L was achieved at 94.22% in 2 hours of contact time by a photocatalysis treatment employing the HA/TiO2 composite at a ratio of 1:1 in comparison to only 92.23% removal by the HA adsorption process.

2

Fabric Treated with Dye Modified TiO2/Graphene Composite and its Photocatalytic and Self-Cleaning Properties

Wen Yu-xin, Bao Li-hong, Ling Jia-wen, Guan-Fanglan, Mei Zhang, Nie-Jinmei

Fibres & Textiles in Eastern Europe

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2022

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Vol. 30, no. 5

53--59

EN

In this paper, a dye modified titanium dioxide/graphene composite (DTG20) was prepared using direct grey D, a dye with good water solubility, as a modifier. Then the DTG20 and its intermediates, including TiO2 and titanium dioxide/graphene (TG), were finished on cotton fabric through the padding, coating and compounding methods, respectively. Photocatalytic properties of the treated fabrics were investigated using the MB simulated pollutant. It was found that the photodegradation efficiency of MB shown by DTG20 finished fabric treated with the compounding method can reach 90.55 %, and after four recycling experiments, the removal rate of MB can still reach 77.07 %. After being exposed to sunlight for 6 hours, the photodegradation efficiency of MB stained on the surface of DTG20 treated fabric can achieve 91.44 %; therefore, it also exhibited an excellent self-cleaning effect.

3

Preparation and Characterization of ZnO-Zeolite Nanocomposite for Photocatalytic Degradation by Ultraviolet Light

Gayatri Rianyza, Agustina Tuty Emilia, Bahrin David, Moeksin Rosdiana, Gustini Gustini

Journal of Ecological Engineering

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2021

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Vol. 22, nr 2

178--186

EN

The increasing growth of the textile industry does not only provide benefits in the economic sector but also has the potential to damage the environment, because it generates the dye wastewater which is hard to eliminate. Procion red is one of the synthetic textile dyes that is toxic to the aquatic environment and it needs to be processed properly. The photocatalytic method of processing dye wastewater is the most effective, because it can remove the harmful pollutants in the dye wastewater. This study aimed to prepare and characterize the ZnO-Zeolite nanocomposites for photocatalytic applications tested with a 50 mg/L procion red dye sample. The nanocomposites consisted of the ZnO semiconductors and synthetic zeolite adsorbents prepared by using the sol-gel method. The dye degradation test was carried out under the irradiation conditions with ultraviolet (UV) lamp. Apart from the ZnO-Zeolite nanocomposite, testing was also carried out with the synthetic zeolite and ZnO. The results of SEM-EDX and XRD characterization proved that the nanocomposite forming components were ZnO and zeolite and could be seen from the resulting peaks. BET showed that the surface area value of the ZnO-Zeolite nanocomposite increased to 95.98 m2/g, the pore size of the ZnO-Zeolite nanocomposite was 4.42 nm, and the total pore volume was 0.08 cm3/g. The obtained average crystalline size of ZnO-Zeolite nanocomposite was 32.87 nm. The percentage of dye degradation using the ZnO-Zeolite nanocomposite for 120 minutes has reached 90.42%.

4

Fotokatalityczna degradacja herbicydów : nowe katalizatory na bazie TiO2

Ożóg S.

Wiadomości Chemiczne

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2015

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[Z] 69, 7-8

606--616

EN

Over the past few decades a rapid increase in standard of living is observed. Rapid urbanization and development of new technologies, which are focused on the needs of a modern society, influence negatively the environment. The present policy of sustainable development is focused on the principles of rational use of scarce resources and raw materials. New technologies should comply with a number of requirements: efficiency, low costs and a low impact on the environment. Photocatalytic processes are the answer for these requirements. Photocatalysis can be used in many aspects of everyday life, offering self-cleaning surfaces, photo-drugs (e.g. for photodynamic therapy) and even photovoltaic devices. Photocatalytic degradation of pollutants in the presence of inorganic photocatalysts (e.g. TiO2 or ZnO) is one of the available methods of removing impurities from aqueous and gaseous phases. The main advantage of this process is the lack of wastes and formation of carbon dioxide, water and simple inorganic ions as end- -products. The aim of our work was to develop new TiO2-based photocatalysts doped with tungsten and molybdenum oxides. A series of materials with different content of the dopants, calcined at various temperatures, was prepared. The photocatalytic activity of the materials was determined following the degradation of two model herbicides: 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). These compounds are used for the control of weed growth on crop plantations, but in a high dosage they can lead to destruction of the plants. They are readily soluble in water, therefore their use is simple, but brings a great risk to aquatic organisms and people. Photocatalytic degradation of herbicides is the main goal of the 4G-PHOTOCAT project. The efforts are directed towards development of a low-cost photocatalytic paint, that could be used in reactors for groundwater purification. The active ingredient of the paint is a composite material based on TiO2 modified with other metal oxides.

5

Ocena efektywności procesu fotodegradacji barwników azowych w obecności tlenku cynku

Adamek E., Baran W., Szołtysek-Bołdys I., Sobczak A.

Proceedings of ECOpole

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2015

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Vol. 9, No. 2

523--531

PL

Trudności w usuwaniu zanieczyszczeń pochodzących z przemysłu włókienniczego (tzw. barwne ścieki) stanowią ważny problem, głównie w krajach rozwijających się. Jest to spowodowane m.in. trwałością i odpornością barwników na procesy biodegradacji oraz niecałkowitym usuwaniem w oczyszczalniach ścieków. Jednym z rozwiązań może być połączenie konwencjonalnego oczyszczania z tzw. metodami pogłębionego utleniania, do których zalicza się procesy fotokatalityczne. Celem niniejszej pracy była ocena efektywności procesu fotokatalitycznej degradacji barwników azowych (kationowych i anionowych) w ich roztworach wzorcowych w obecności tlenku cynku (ZnO) jako fotokatalizatora. Dla roztworu każdego barwnika, przy różnym pH (3,0-10,5) oraz dla różnych ilości ZnO (25-500 mg), wyznaczano stopień adsorpcji, stopień fotodegradacji oraz stałe szybkości reakcji degradacji. Stwierdzono, że wszystkie badane barwniki były odporne na fotolizę, a w obecności ZnO i pod wpływem promieniowania UV uległy fotokatalitycznej degradacji. Omawiane procesy rozkładu przebiegały każdorazowo zgodnie z kinetyką reakcji pseudopierwszego rzędu względem degradowanego barwnika. Najkorzystniejsze warunki do przeprowadzenia fotokatalitycznej degradacji dla prawie wszystkich barwników to pH 8,5-9,5 oraz 1,0 g ZnO/dm3. Wykazano również zależność pomiędzy stopniem adsorpcji barwników na powierzchni fotokatalizatora i stopniem ich fotodegradacji a pH roztworu i budową barwnika.

EN

Difficulties in removing of pollutants from textile industry (the so-called coloured effluent) are a significant problem, particularly in the developing countries. It is caused by, among other, stability and resistance of dyes to biodegradation processes and incomplete removal of dyes in wastewater treatment plants. One of the solutions may be a combination of the conventional, mechanical-biological treatment with advanced oxidation processes, which include photocatalytic processes. The aim of this study was to evaluate the efficiency of photocatalytic degradation of azo dyes (cationic and anionic) in the standard solutions in the presence of zinc oxide (ZnO) as a photocatalyst. The degree of dyes adsorption, the degree of photodegradation and reaction rate constants were determined in each dye solution at different pH values (3.0-10.5) and at different amounts of ZnO (25-500 mg). All the investigated azo-dyes were resistant to photolysis and they underwent the photocatalytic degradation in the presence of ZnO and under UV-irradiation. In each case the processes were carried out in accordance with the kinetics of pseudo-first order reaction with respect to the degraded dye. The most favourable conditions to the photocatalytic degradation for almost all azo-dyes were: pH 8.5-9.5 and 1.0 g ZnO/dm3. Additionally, a relationship between the degree of dyes adsorption on the photocatalyst surface, the degree of photodegradation and pH of the dyes solutions and the dye structure was also stated.

6

Preparation of TiO2/Al-MCM-41 mesoporous materials from coal-series kaolin and photodegradation of methyl orange

Li S., Wu Q., Cui C., Lu G., Zhang C., Zhiye Y.

Materials Science Poland

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2013

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Vol. 31, No. 3

372--377

EN

TiO2/Al–MCM-41 mesoporous materials were prepared via sol-gel method by loading titania onto Al–MCM-41 mesoporous molecular sieve by hydrothermal treatment from coal-series kaolin as raw material. The TiO2/Al–MCM-41 mesoporous materials were characterized by XRD, FT-IR, HRTEM, N2 adsorption-desorption and the photocatalytic degradation of methyl orange solution under visible light irradiation. The results showed that the TiO2/Al–MCM-41 mesoporous materials possessed a high surface area of 369.9 – 751.3 m2/g and a homogeneous pore diameters of 2.3 – 2.8 nm. The titania crystalline phase was anatase, and the particles size of TiO2 increased with TiO2 content. The Al–MCM-41 mesoporous materials exhibited excellent photodegradation activity under visible-light irradiation for methyl orange.

7

Badania nad rozkładem benzo[a]pirenu na powierzchni farby o właściwościach fotokatalitycznych

Orlikowski J., Tryba B., Morawski A. W.

Przemysł Chemiczny

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2012

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T. 91, nr 9

1775-1778

PL

Przeprowadzono fotokatalityczny rozkład benzo[a]pirenu (BAP) na powierzchni farby o właściwościach fotokatalitycznych zawierającej TiO₂. Do badań wykorzystano farbę fotokatalityczną firmy Pigment, którą naniesiono na szklaną płytkę. BAP naniesiony był na powierzchnię farby z roztworu acetonu. Badania fotokatalitycznego rozkładu BAP prowadzone były pod wpływem naświetlania sztucznym światłem słonecznym. Stężenie BAP na powierzchni farby analizowano na podstawie pomiarów widm UV -VIS/DR in situ, natomiast zmianę powierzchni chemicznej farby z BAP podczas jego fotokatalitycznego rozkładu obserwowano na wykonanych in situ pomiarach widm w podczerwieni (FT-IR/DRS). Badania UV-VIS/DR próbek wykazały stopniowe zanikanie pików charakterystycznych dla BAP wraz z czasem naświetlania, a badania FT-IR/DRS wzrost intensywności pasm pochodzących od produktów jego rozkładu. Po upływie 900 h na widmach UV-VIS/DR nastąpił niemal całkowity zanik sygnałów BAP na powierzchni farby fotokatalitycznej.

EN

Benzo[a]pyrene was deposited in AcMe soln. on the surface of TiO₂-contg. photocatalytic paint supported on glass plates and decompd. under artificial solar light irradn. A gradual disappearance of IR peaks attributed to benzo[a]pyrene was obsd. After 900 h of irradn. almost complete degrdn. of benzo[a]pyrene was achieved.

8

Photocatalytic degradation of malachite green dye using doped and undoped ZnS nanoparticles

Tolia J., Chakraborty M., Murthy Z. V. P.

Polish Journal of Chemical Technology

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2012

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Vol. 14, nr 2

16-21

EN

In the present study, ZnS nanoparticles were prepared using the mechanochemical method. The ZnS nanoparticles prepared were doped with different concentrations of manganese using metal acetate and manganese acetate by mechanochemical method. The as-prepared particles were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The photocatalytic activity of the prepared nanoparticles samples, in the photocatalytic degradation of malachite green, had been investigated. The nanoparticles were photo induced, generating hole transfer for photocatalytic activity. The photodegradation of malachite green was observed at different pH (2-5) values, dye concentrations (10-100mg/L) and amount of ZnS nanoparticles (1-2.5 g/L). About 95% degradation of dye was observed on the addition of 2 g/L ZnS in 50 mg/L dye solution after 90 minutes illumination at 125 W. Degradation has been increased up to 99% using UV/nanoparticles/H2O2 (50 mL/L) combined process. The degradation efficiency was also compared using Mn doped ZnS nanoparticles (Zn1-x MnxS, where x = 0.01, 0.22 and 0.3). Maximum of 97% degradation was observed with 0.01% concentration of Mn. Kinetics study and performance of UV/ZnS, UV/ZnS/H2O2, UV/doped ZnS processes were evaluated to compare the efficiency of different processes.

9

Photocatalytic degradation of an organic dye in some aqueous buffer solutions using nano titanium dioxide: A kinetic study

Montazerozohori M., Nasr-Esfahani M., Joohari S.

Environment Protection Engineering

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2012

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Vol. 38, nr 3

45--55

EN

Photocatalytic degradation of an organic dye, emerald green, on nano titanium dioxide (anatase 99.5%) at basic buffer pH of 7, 8 and 9 has been investigated. The effects of various operating parameters such as initial concentration of dye, catalyst dosage, bufferic pH and irradiation time on photocatalytic degradation have been studied in a photoreactor cell containing high pressure mercury lamp to obtain the optimum conditions. COD removal was found to be 65-71% confirming considerable mineralization. The photodegradation of the dye obeyed a pseudo-first order kinetics according to the Langmuir-Hinshelwood model at all used buffer pH. The observed rate constants (Kobs) of photocatalytic degradation were 3.3 ×10-2 min-1, 7.09 × 10-2 min-1 and 1.32 × 10-1 min-1 at buffer pH of 7-9 respectively. Furthermore, the Langmuir-Hinshelwood rate constants, kr and adsorption constants, KA are reported for current process at various buffer pH.

10

Fotokatalityczna degradacja gentamycyny w roztworach wodnych

Makowski A., Baran W., Adamek E., Nocoń W.

Proceedings of ECOpole

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2011

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Vol. 5, No. 2

561--566

PL

Metody zawansowanego utleniania polegające na powstawaniu wysokoreaktywnych rodników hydroksylowych są stosowane do usuwania substancji leczniczych z roztworów wodnych. Mogą być stosowane do degradacji antybiotyków i ich metabolitów do związków przejściowych, które następnie ulegają łatwiejszej biodegradacji. Same antybiotyki należą do tzw. związków refrakcyjnych, czyli nieulegających łatwo biodegradacji. Roztwory gentamycyny naświetlano promieniowaniem UV λ = 366 nm w obecności fotokatalizatora P 25 Degussa. Zawartość gentamycyny badano metodą HPLC. Stałe szybkości fotokatalitycznego rozkładu wyznaczano z zależności logC/Co od czasu trwania procesu. Jony żelaza i kobaltu przyspieszają proces fotokatalitycznego rozpadu gentamycyny, natomiast jony miedzi, wapnia i magnezu spowalniają ten proces. Na powierzchni P 25 następuje proces adsorpcji gentamycyny; proces ten nasila się w obecności jonów metali, zwłaszcza jonów żelaza. Najszybsza mineralizacja gentamycyny następuje również w obecności jonów żelaza. Jony żelaza, wapnia i magnezu tworzą kompleksy z gentamycyną o stosunku molowym 1:1, rozpadające się w trakcie naświetlania. Jony miedzi osadzają się na powierzchni fotokatalizatora podczas procesu fotokatalitycznego.

EN

Drugs and their metabolites belong to the group of compounds which can be micropollutants present in surface waters, sewage and soil. The widespread use of pharmaceuticals for the human health care results in their undesirable accumulation in the environment. The most hazardous groups of drugs are antibiotics because they are hardly biodegradable and can cause the formation of a drug resistance in numerous bacteria strains. The aim of the work was to investigate of the photocatalytic degradation of aminoglycoside antibiotic, namely gentamicin, the influence of metal ions (Fe2+, Co2+, Cu2+, Mg2+ and Ca2+). It was stated that the iron and cobalt ions accelerated the process of the photocatalytic degradation of gentamicin, while copper, calcium and magnesium slowed down this process. It was observed the adsorption of gentamicin on the photocatalyst surface. The fastest mineralization of organic substances was obtained in the presence of iron ions. It was found that the iron ions formed stable complexes with gentamicin (in the molar ratio 1:1).

11

Fotokatalityczna degradacja cefuroksymu w roztworach wodnych

Makowski A., Adamek E., Baran W., Sobczak A., Nocoń W.

Proceedings of ECOpole

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2011

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Vol. 5, No. 2

547--552

PL

Leki i ich metabolity są mikrozanieczyszczeniami ścieków, gleby i wód powierzchniowych. Najbardziej niebezpieczne wśród nich są antybiotyki, gdyż jako związki tzw. refrakcyjne są trudno biodegradowalne i powodują powstawanie zjawiska lekooporności wielu szczepów bakterii. Zaawansowane metody utleniania (AOP) są rozwijanymi powszechnie technologiami oczyszczania ścieków, wód gruntowych i powierzchniowych z zanieczyszczeń organicznych. Polegają one na generowaniu rodników hydroksylowych (OH), o wysokim potencjale utleniającym, które są zdolne zmineralizować związki organiczne. Roztwory antybiotyków naświetlano promieniowaniem UV λ = 366 nm w obecności fotokatalizatora P 25 Degussa. Zawartość cefuroksymu i jego produktów przejściowych w czasie fotokatalitycznej degradacji badano metodą HPLC. Kationy metali obecne w roztworze mogą zmieniać szybkość fotokatalitycznej degradacji, gdyż mogą adsorbować się na powierzchni fotokatalizatora i tworzyć połączenia kompleksowe. Stałe szybkości fotokatalitycznego rozkładu cefuroksymu wyznaczano z zależności logC/Co od czasu trwania procesu. Jony żelaza przyspieszają ten proces, natomiast jony ceru, miedzi, magnezu i wapnia spowalniają go. Na powierzchni fotokatalizatora adsorbuje się cefuroksym, szczególnie gdy w roztworze są obecne jony żelaza.

EN

In the recent years, much attention has been given to the micropollutans in the environment, ie drugs and their metabolites. Beta lactams antibiotics, such as penicillin, ampicillin and cefuroxime are excreted in an unchanged form (60÷90%). It can be threat to human health because the presence of antibiotics in the environment causes the evolution of drug-resistance in several bacteria strains. The advanced oxidation methods are used to remove antibiotics from water solutions.They can be effectively used to degrade antibiotics to the intermediate metabolites, which are then easily biodegradable. The objective of this work was to study the photocatalytic degradation of cefuroxime and the effect of metal ions Fe3+, Cu2+, Ca2+, Mg2+ and Ce3+ as well as determination of the optimal pH range for this process.The solutions were irradiated with 366 nm in presence of TiO2 P 25 as a photocatalyst. It was stated that the addition of iron to the cefuroxime solution increased the rate in the photocatalytic degradation while the copper, calcium, magnesium and cerium ions decreased the degradation rate of antibiotic. It was noticed the adsorption of cefuroxime on the photocatalyst surface. The optimum pH range for the photodegradation process was 6.1. Moreover, the TOC concentrations were compared during the photocatalytic degradation in cefuroxime solutions and in solutions with iron ions. Interactions of cefuroxime with Fe3+ and Ca2+ ions were measured using conductometric method. It was observed that these meatals formed complexes with cefuroxime in the molar ratio 1:1.

12

Fotokatalityczna degradacja doksycykliny w roztworach wodnych

Makowski A., Sobczak A., Wcisło D., Adamek E., Baran W., Kostecki M.

Proceedings of ECOpole

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2009

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Vol. 3, No. 1

87--94

PL

Wśród substancji stanowiących mikrozanieczyszczenia wód powierzchniowych, ścieków i gleby znajdują się leki i ich metabolity. Najbardziej niebezpieczne są antybiotyki, gdyż są trudno biodegradowalne i wywołują powstawanie zjawiska lekooporności wielu szczepów bakterii. Zaawansowane procesy utleniania są powszechnie akceptowanymi technologiami oczyszczania ścieków, wód gruntowych i powierzchniowych z opornych i trudno biodegradowalnych zanieczyszczeń organicznych. Polegają one na generowaniu rodników hydroksylowych (•OH) o wysokim potencjale utleniającym, które są zdolne zmineralizować związki organiczne. Roztwory antybiotyków naświetlano promieniowaniem UV λ = 366 nm w obecności fotokatalizatora P 25 firmy Degussa. Zawartość doksycykliny i jej produktów przejściowych podczas fotokatalitycznej degradacji badano metodą HPLC. Stałe szybkości fotokatalitycznego rozkładu doksycykliny wyznaczano z zależności logC/Co od czasu trwania procesu. Jony żelaza i kobaltu przyśpieszają proces fotokatalitycznego rozpadu doksycykliny, natomiast jony miedzi, wapnia, magnezu i jony fosforanowe spowalniają ten proces. Na powierzchni P 25 następuje proces adsorpcji doksycykliny, największy w przypadku obecności w roztworze jonów żelaza. Jony miedzi ulegają w trakcie procesu redukcji i miedź osadza się na powierzchni fotokatalizatora. Optymalnym odczynem podczas procesu jest pH równe 6,8; nie znaleziono jednak korelacji pomiędzy stałymi szybkości rozpadu doksycykliny a pH roztworu.

EN

Drugs and their metabolites are among substances which micro-pollute surface waters, sewage and soil. Antibiotics are the most hazardous, as they are hardly biodegradable and trigger the formation of drug resistance of numerous bacteria strains. The advanced oxidation processes (OP) are widely accepted techniques for removing resistant and hardly biodegradable organic pollutants from sewage, as well as ground and surface waters. They involve generating hydroxylic radicals (•OH) with high oxidation potential, which are able to mineralize organic compounds. This work aims at testing the photocatalytic degradation of doxycycline and the influence of metal ions Fe3+, Cu2+, Ca2+, Mg2+, Co2+ and phosphate ions on this process, as well as at determining the optimum pH range for this process. The solutions were irradiated with UV λ = 366 nm in the presence of P 25 Degussa photocatalyst. The content of doxycycline and its transient products during photocatalytic degradation was tested using the HPLC method. To estimate the photocatalytic degradation rate constants of doxycycline, the relationship log C/Co from time of duration of photocatalytic process were determined. The iron and cobalt ions accelerate the process of photocatalytic doxycycline breakdown, while the copper, calcium, magnesium and phosphate ions slow down this process. The process of doxycycline adsorption takes place in the presence of metal ions, particularly iron. The fastest mineralization of organic substances takes place in the presence of iron ions. The copper ions are reduced during the process and copper forms a deposit on the photocatalyst. The optimum pH of the solution during the photocatalytic process is 6.8. However, no correlation was found between the constants of doxycycline breakdown rate and and pH of the solution.

13

Fotokatalityczna degradacja ampicyliny w roztworach wodnych

Makowski A., Sobczak A., Wcisło D., Adamek E., Baran W., Nocoń W.

Proceedings of ECOpole

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2009

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Vol. 3, No. 1

81--86

PL

Metody zaawansowanego utleniania, polegające na generowaniu reaktywnych rodników hydroksylowych, są stosowane do usuwania antybiotyków z roztworów wodnych. Mogą być też stosowane do degradacji antybiotyków do związków przejściowych, które następnie ulegają łatwiej biodegradacji. Roztwory antybiotyków naświetlano promieniowaniem UV λ = 366 nm w obecności fotokatalizatora P 25 Degussa. Zawartość ampicyliny i jej produktów przejściowych w trakcie fotodegradacji badano metodą HPLC. Stałe szybkości rozkładu ampicyliny wyznaczano z zależności logC/Co od czasu trwania procesu. Dodatek jonów żelaza do roztworu ampicyliny powoduje nieznaczny spadek szybkości jej degradacji. Wpływ jonów miedzi zależy od stosunku molowego metalu do antybiotyku. Wpływ jonów wapnia na szybkość rozpadu ampicyliny jest niewielki, natomiast w przypadku jonów magnezu i jonów kobaltu powoduje spadek szybkości degradacji ampicyliny. Na powierzchni katalizatora P 25 adsorbuje się ampicylina; proces ulega zmianie w obecności jonów metali i jonów fosforanowych.

EN

The advanced oxidation methods are applied to remove antibiotics from water solutions. They involve generating hydroxylic radicals (.OH) with high oxidation potential, which are able to mineralize organic compounds. They can be use to degrade antibiotics to transient metabolites, which are then easily biodegradable. They were irradiated with UV λ = 366 nm in the presence of P 25 Degussa photocatalyst. The level of ampicillin and its transient products during photocatalytic degradation was tested using the HPLC method. To estimate the photocatalytic degradation rate constants of ampicillin, the relationship log C/Co from time of duration of photocatalytic process were defined. The addition of iron ions to the ampicillin solution slightly slows down its photocatalytic degradation. The influence of copper ions on the speed of ampicillin degradation depends on the molar ratio of metal to antibiotic. The influence of calcium ions on the speed of ampicillin breakdown is not too significant, while in the case of magnesium ions, similar to cobalt ions, the ampicillin breakdown slows down. Ampicillin is adsorbed on the surface of P 25 catalyst; the process changes in the presence of metal ions and phosphate ions. The optimum of environment during the photodegradation process is pH reaction 7.2.

14

Photocatalytic Degradation of Crystal Violet by Use of Copper Oxide as Semiconductor

Shah A., Mittal N., Bhati I., Sharma V. K., Punjabi P. B.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 11

2001-2007

EN

The photocatalytic degradation of crystal violet on copper oxidesemi conductor suspended in aqueous solution has been carried out. The progress of reaction has been studied spectrophotometrically by observing absorbance of reaction mixture at different time intervals. The effects of various parameters such as concentration of crystal violet, pH of reaction mixture amount of semiconductor and intensity of light on the rate of reaction have also been observed. The photocatalytic degradation of crystal violet follows pseudo first order kinetics and the rate constant has been determined. Atentative mecha nism for the reaction has also been proposed.