Methylene blue removal from contaminated waters using O3, natural zeolite, and O3/zeolite

2009 ◽  
Vol 60 (6) ◽  
pp. 1419-1424 ◽  
Author(s):  
H. Valdés ◽  
R. F. Tardón ◽  
C. A. Zaror
Keyword(s):  
Methylene Blue ◽  
Natural Zeolite ◽  
Flow Reactor ◽  
Removal Rate ◽  
Experimental System ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Oxidation Reactions ◽  
Simultaneous Treatment ◽  
Ozone Oxidation

This paper compares experimental results on methylene blue (MB) removal systems based on ozone oxidation, zeolite adsorption, and simultaneous adsorption-oxidation using ozone in the presence of natural zeolite. The effect of pH (2–8), and the presence of radical scavengers (sodium acetate) on process rates and removal efficiencies are assessed at laboratory scale. The experimental system consisted of a 1 L differential circular flow reactor and an ozone generator rated at 5 g O3/h. Results show that ozone oxidation combined with zeolite adsorption increases the overall MB oxidation rate with respect to ozonation process and zeolite adsorption. In presence of free radical scavenger, only a 25% of reduction on MB removal rate are observed in the simultaneous treatment, as compared with 70% when ozonation treatment is used, suggesting that MB oxidation reactions take mainly place on the zeolite surface.

Advanced treatment of benzothiazole contaminated waters: comparison of O3, AC, and O3/AC processes

2005 ◽  
Vol 52 (10-11) ◽  
pp. 281-288 ◽  
Author(s):  
H. Valdés ◽  
C.A. Zaror
Keyword(s):  
Activated Carbon ◽  
Flow Reactor ◽  
Removal Rate ◽  
Carbon Surface ◽  
Advanced Treatment ◽  
Radical Scavenger ◽  
Activated Carbon Adsorption ◽  
Simultaneous Treatment ◽  
Ozone Oxidation ◽  
Carbon Adsorption

Benzothiazole (BT) is a toxic and poorly biodegradable contaminant, usually found in wastewater from rubber related applications. This compound could be effectively eliminated using advanced treatment processes. This paper compares experimental results on detoxification systems based on ozone oxidation, activated carbon adsorption, and simultaneous adsorption-oxidation using ozone in the presence of activated carbon. The effect of pH (2–11), and the presence of radical scavengers (tert-butyl alcohol and sodium carbonate) on process rates and removal efficiencies are assessed at laboratory scale. The experimental system consisted of a 1L differential circular flow reactor and an ozone generator rated at 5g O3/h. Results show that ozone oxidation combined with activated carbon adsorption increases the overall BT oxidation rate with respect to the ozonation process and activated carbon adsorption. In the presence of free radical scavenger, only a 44% reduction in BT removal rate is observed in the simultaneous treatment, as compared with 72% when ozonation treatment is used, suggesting that BT oxidation reactions mainly take place on the activated carbon surface.

scholarly journals UJI AKTIVITAS ANTIOKSIDAN EKSTRAK ETANOL ALGA Ulva lactuca MENGGUNAKAN METODE DPPH (1,1 diphenyl-2-picrylhydrazyl)

PHARMACON ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 535
Author(s):  
Gia Aprilia Kartini Ulaan ◽  
Adithya Yudistira ◽  
Henki Rotinsulu
Keyword(s):  
Antioxidant Activity ◽  
Ethanol Extract ◽  
Free Radical Scavenger ◽  
Ulva Lactuca ◽  
Radical Scavenger ◽  
Oxidation Reactions ◽  
Shallow Marine ◽  
Lembeh Strait ◽  
Dpph Method ◽  
Ethanol Extracts

Ulva lactuca Algae habitat was found in shallow marine waters and its morphology is thin and flat thallus. Ulva lactuca Algae, known as sea lettuce, contains a lot of chlorophyll in its cells. Chlorophyll has the ability as a free radical scavenger and also has antioxidant activity. Antioxidants are compounds that could inhibit oxidation reactions by binding to free radicals and highly reactive molecules. This study was conducted to determine the antioxidant activity of ethanol extract of Algae Ulva lactuca obtained from the Lembeh Strait, Bitung City. Ulva lactuca Algae was extracted by maceration method using ethanol solvent. Testing of antioxidant activity was carried out using the DPPH method, which was measured using a UV-VIS spectrophotometer. The results showed that the ethanol extracts of Ulva lactuca Algae had antioxidant activity with a percentage value of 51.63% at a concentration of 100 mg/L. Keywords : Ulva lactuca Algae, Antioxidants, Ethanol, DPPHABSTRAKHabitat tumbuhan Alga Ulva lactuca terdapat di air laut dan morfologinya berupa thallus tipis dan gepeng. Alga Ulva lactuca yang dikenal dengan selada laut, banyak mengandung klorofil dalam sel-selnya. Klorofil memiliki kemampuan sebagai penangkap radikal bebas dan juga memiliki aktivitas antioksidan. Antioksidan merupakan senyawa yang dapat menghambat reaksi oksidasi dengan cara mengikat radikal bebas dan molekul yang sangat reaktif. Penelitian ini dilakukan untuk mengetahui aktivitas antioksidan dari ekstrak etanol Alga Ulva lactuca yang diperoleh dari Peraian Selat Lembeh, Kota Bitung. Alga Ulva lactuca diekstrak dengan metode maserasi menggunakan pelarut etanol. Pengujian aktivitas antioksidan dilakukan dengan metode DPPH yang di ukur menggunakan Spektrofotometer UV-VIS. Hasil penelitian menunjukkan bahwa ekstrak etanol Alga Ulva lactuca memiliki aktivitas antioksidan dengan nilai presentase sebesar 51,63% pada konsentrasi 100 mg/L. Kata kunci : Alga Ulva lactuca, Antioksidan, Etanol, DPPH

The role of reactive oxygen species in Staphylococcus aureus photoinactivation by methylene blue

2008 ◽  
Vol 58 (5) ◽  
pp. 1047-1054 ◽  
Author(s):  
Sonia Sabbahi ◽  
Zoubeir Alouini ◽  
Meryam Jemli ◽  
Abdellatif Boudabbous
Keyword(s):  
Staphylococcus Aureus ◽  
Methylene Blue ◽  
Singlet Oxygen ◽  
Sodium Azide ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Type I ◽  
Survival Fraction ◽  
Photodynamic Activity ◽  
Singlet Oxygen Quencher

Methylene blue (MB) has been shown to photoinduce the direct inactivation of Gram-positive bacteria Staphylococcus aureus (S. aureus) in water. We have investigated the mechanism of S. aureus photoinactivation conducting firstly sodium azide (reactive ion N3−), as a good physical singlet oxygen quencher, then the amino acids tryptophan (Trp), as a non-specific singlet oxygen quencher and the mannitol, as an hydroxyl free radical scavenger. Inactivation of MB photosensitization is the antioxidants type dependent. When the bacteria was treated with MB (20 μM) under light during 10 min of exposure, it was found that survival fraction had decreased dramatically to about 31.27±5.39%. The presence of sodium azide and Trp failed to shown any protection from the MB photodynamic activity. In the presence of mannitol, S. aureus could be protected, reaching a protection level of about 27%. It is possible that the photodynamic activity of MB occurred in part, via a Type I mechanism in which •OH was produced. The interactions between MB and S. aureus were studied spectrophotometrically. This demonstrated that a metachromatic reaction took place between MB and S. aureus bacteria. Furthermore, S. aureus bacteria induced additional dimerization of MB.

Heterogeneous catalytic ozonation of cationic dyes using volcanic sand

2010 ◽  
Vol 61 (12) ◽  
pp. 2973-2978 ◽  
Author(s):  
H. Valdés ◽  
H. P. Godoy ◽  
C. A. Zaror
Keyword(s):  
Methylene Blue ◽  
Removal Rate ◽  
Heterogeneous Systems ◽  
Catalytic Ozonation ◽  
Free Radical Scavengers ◽  
Oxidation Reactions ◽  
Radical Scavengers ◽  
Chemical Surface ◽  
Heterogeneous Catalytic ◽  
Methylene Blue Removal

This work aims to present experimental results on the treatment of methylene blue contaminated waters using heterogeneous catalytic ozonation promoted by volcanic sand. The effect of pH (2–8), and the presence of radical scavengers (acetate ions) in homogeneous and heterogeneous systems are evaluated at laboratory scale. Heterogeneous catalytic ozonation using volcanic sand increases methylene blue removal rate. In the presence of free radical scavengers, only a 37% reduction on methylene blue removal rate is observed in the heterogeneous system, as compared with 70% when homogeneous ozonation is used. The results obtained here indicate the importance of chemical surface properties on methylene blue oxidation reactions, suggesting that acid surface sites of volcanic sand play a key role on the reaction mechanism.

Melatonin reduces high levels of lipid peroxidation induced by potassium iodate in porcine thyroid

2019 ◽  
pp. 1-7 ◽  
Author(s):  
Paulina Iwan ◽  
Jan Stepniak ◽  
Malgorzata Karbownik-Lewinska
Keyword(s):  
Lipid Peroxidation ◽  
Oxidative Damage ◽  
Membrane Lipids ◽  
Chemical Properties ◽  
Iodine Concentration ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Protective Effects ◽  
Potassium Iodate ◽  
Hormone Synthesis

Abstract. Iodine is essential for thyroid hormone synthesis. Under normal iodine supply, calculated physiological iodine concentration in the thyroid is approx. 9 mM. Either potassium iodide (KI) or potassium iodate (KIO3) are used in iodine prophylaxis. KI is confirmed as absolutely safe. KIO3 possesses chemical properties suggesting its potential toxicity. Melatonin (N-acetyl-5-methoxytryptamine) is an effective antioxidant and free radical scavenger. Study aims: to evaluate potential protective effects of melatonin against oxidative damage to membrane lipids (lipid peroxidation, LPO) induced by KI or KIO3 in porcine thyroid. Homogenates of twenty four (24) thyroids were incubated in presence of either KI or KIO3 without/with melatonin (5 mM). As melatonin was not effective against KI-induced LPO, in the next step only KIO3 was used. Homogenates were incubated in presence of KIO3 (200; 100; 50; 25; 20; 15; 10; 7.5; 5.0; 2.5; 1.25 mM) without/with melatonin or 17ß-estradiol. Five experiments were performed with different concentrations of melatonin (5.0; 2.5; 1.25; 1.0; 0.625 mM) and one with 17ß-estradiol (1.0 mM). Malondialdehyde + 4-hydroxyalkenals (MDA + 4-HDA) concentration (LPO index) was measured spectrophotometrically. KIO3 increased LPO with the strongest damaging effect (MDA + 4-HDA level: ≈1.28 nmol/mg protein, p < 0.05) revealed at concentrations of around 15 mM, thus corresponding to physiological iodine concentrations in the thyroid. Melatonin reduced LPO (MDA + 4-HDA levels: from ≈0.97 to ≈0,76 and from ≈0,64 to ≈0,49 nmol/mg protein, p < 0.05) induced by KIO3 at concentrations of 10 mM or 7.5 mM. Conclusion: Melatonin can reduce very strong oxidative damage to membrane lipids caused by KIO3 used in doses resulting in physiological iodine concentrations in the thyroid.

OPTIMASI KONDISI EKSTRAKSI SENYAWA AKTIF ANTIOKSIDAN DARI BIJI ANGGUR

2019 ◽  
Vol 3 (2) ◽  
pp. 35
Author(s):  
Kartini Kartini ◽  
Azminah Azminah
Keyword(s):  
Free Radical ◽  
Optimum Condition ◽  
Active Compound ◽  
Grape Seed ◽  
Free Radical Scavenger ◽  
Water Bath ◽  
Radical Scavenger ◽  
Optimum Conditions ◽  
Ethanolic Solution ◽  
Reduced Pressure

In order to prepare standardized extract, optimization of extraction conditions of grape seed has been done. These conditions are type of menstrum (50, 70 and 96% of ethanolic solution), length of extraction (1, 2 and 4 hours) also method of evaporation (reduced pressure and opened air). Activity on free radical scavenger used as parameters to determine optimum conditions. Based on EC50 (concentration which scavenge 50% amount of free radical) can be concluded that optimum condition for extracting antioxidant active compound from grape seed are 70% ethanolic solution as menstrum, length of extraction 1 hour and evaporation on opened air use water bath.

scholarly journals Suppression of Inflammation-Associated Kidney Damage Post-Transplant Using the New PrC-210 Free Radical Scavenger in Rats

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1054
Author(s):  
Torsten R. Goesch ◽  
Nancy A. Wilson ◽  
Weifeng Zeng ◽  
Bret M. Verhoven ◽  
Weixiong Zhong ◽  
...  
Keyword(s):  
Protective Efficacy ◽  
Serum Levels ◽  
Rat Plasma ◽  
Free Radical Scavenger ◽  
Kidney Damage ◽  
Brown Norway ◽  
Radical Scavenger ◽  
Organ Protection ◽  
Antibody Mediated Rejection ◽  
Allograft Kidney

Allograft kidney transplantation, which triggers host cellular- and antibody-mediated rejection of the kidney, is a major contributor to kidney damage during transplant. Here, we asked whether PrC-210 would suppress damage seen in allograft kidney transplant. Brown Norway (BN) rat kidneys were perfused in situ (UW Solution) with or without added 30 mM PrC-210, and then immediately transplanted into Lewis (LEW) rats. 20 h later, the transplanted BN kidneys and LEW rat plasma were analyzed. Kidney histology, and kidney/serum levels of several inflammation-associated cytokines, were measured to assess mismatch-related kidney pathology, and PrC-210 protective efficacy. Twenty hours after the allograft transplants: (i) significant histologic kidney tubule damage and mononuclear inflammatory cell infiltration were seen in allograft kidneys; (ii) kidney function metrics (creatinine and BUN) were significantly elevated; (iii) significant changes in key cytokines, i.e., TIMP-1, TNF-alpha and MIP-3A/CCL20, and kidney activated caspase levels were seen. In PrC-210-treated kidneys and recipient rats, (i) kidney histologic damage (Banff Scores) and mononuclear infiltration were reduced to untreated background levels; (ii) creatinine and BUN were significantly reduced; and (iii) activated caspase and cytokine changes were significantly reduced, some to background. In conclusion, the results suggest that PrC-210 could provide broadly applicable organ protection for many allograft transplantation conditions; it could protect transplanted kidneys during and after all stages of the transplantation process—from organ donation, through transportation, re-implantation and the post-operative inflammation—to minimize acute and chronic rejection.

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