Large Amount Of Dyes Research Articles

Changing cellulose acetate deriving from cigarette filters to be used as catalyst in effluent treatment

Cigarette butts are a significant environmental issue, mainly when they are improperly discarded. However, this waste type is recyclable, since its structure is based on cellulose acetate, which is used in the industrial sector for absorbent and filtering purposes. The aim of the present study is to chemically change cellulose acetate deriving from cigarette filters by incorporating iron to it, in order to use it as catalyst in effluent treatment processes. Three different methods were used for iron immobilization purposes in basic, acidic and ferric media, for 7 days. The method showing the best iron adsorption, based on spectroscopic analyses, was the one wherein cigarette butts remained in contact with 0.1 mol/L ferric solution. Therefore, the group of cigarette butts resulting from this method was used in Fenton and photo-Fenton processes. Moreover, it recorded positive results for textile dye mix discoloration, as evidenced by spectral changes in the 350-700 nm range, which pointed out significant color change in the assessed sample. Although the current article results from a preliminary study, the herein collected data point towards the potential use of cigarette butts as alternative to treat effluents deriving from companies that use large amounts of dye.

The effect of applying lead ion to the surface of TiO2 on dye-adsorption rate and photovoltaic properties of solar cells

Lead ion was incorporated into TiO2 layers prepared on an F-doped tin oxide (FTO) substrate. The resulting electrodes (Pb2+-TiO2/FTO) were sensitized with N719 dye and put to use in dye-sensitized solar cells (DSCs). Owing to the electrostatic attraction between the positively charged TiO2 and the carboxylate anions (–COO−) in the N719 dye, more dye was adsorbed into the Pb2+-TiO2/FTO, which required only 2 h for sensitization, than in a reference TiO2/FTO electrode that was sensitized for 8 h. The power conversion efficiency of a DSC with the Pb2+-TiO2/FTO rose to 10.01 % over the efficiency (9.29 %) of the reference device. It was found that the increased dye adsorption in the Pb2+-TiO2/FTO allowed the cells to more efficiently harvest light and collect electrons, resulting in a higher short-circuit current in the DSC. The larger amount of dye also induced a higher open-circuit voltage in the cell by increasing the total number of photoinjected electrons and prolonging their lifetime.

Recent Trends and Advances in the Removal of Dyes from Industrial Wastewater Using Low Cost Adsorbents

Dyes are complex class of organic compound having wide range of applications in textile and food industries and a large amount of dyes are wasted, which get mixed in natural water resources, and pollute environment. Mixing of dyes in water resources must be prohibited for the safety of natural ecosystem. Dyes are used for coloring textiles, wool, leather, paper and fibers. Natural dyes like indigo have been in use for over 5000 years. Natural dyes are replaced by synthetic dyes because of their low cost and vast range of new colors. Today, there are more than 10,000 dyes with different chemical structures available commercially. The natural and modified adsorbents are being successfully used for the adsorption of dyes from wastewater. Importance of several adsorbents like industrial waste, agricultural waste and clay adsorbents of both raw and modified for adsorption of dyes from textile wastewater has been highlighted in this review article. In this review we cover the regeneration capacity and adsorption efficiency of different adsorbents for the treatment of industrial dyes to control water pollution. We also reviewed wide variety of techniques and materials that have been used to remove organic pollutants from water. some adsorption techniques are cost-effective, ecofriendly, clay-supported adsorbents are widely because if their simplicity and good efficiency.
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Research on reuse of standing dye bath of reactive dye

The aim of the work was to find out suitable method of dyeing so that costly reactive dye bath can be reused without draining them. Because of the hydrolysis of residual reactive dyes due to the fixation conditions and because of relatively large amounts of dyes and salts left in the effluent, reusing hydrolyzed reactive dyes is a challenge to dyers. Two reactive dyes were examined (reactive red, reactive yellow and two fabrics: nylon, silk as well as silk fiber and nylon yarn). When using suitable dyeing conditions by controlling pH and temperature, hydrolyzed reactive dye baths for silk and nylon dyeing showed very good wash and moderate colorfastness.

To enhance the dyeability of cotton fiber with the application of reactive dyes by using chitosan

Due to growing environmental concerns, the research on coloration of textiles with reactive dyes is gaining special attention nowadays because of their maximum usage, excellent wet fastness and friendliness. One disadvantage of reactive dye is the hydrolysis, due to which a large amount of dye does not fix the fabric leading to extensive washing. The present study deals with increasing dyeability and functionality of cotton reactive dyeing using chitosan. In conventional reactive dyeing method, salt and alkali’s concentration are more used generating effluent, which is harmful for marine life, crops and also for human health. For overcoming this problem, we have used a chemical name as chitosan due to which concentration of salt and alkali will be reduced. Different reactive dyes were applied on woven fabric pretreated with chitosan and comparison was made. Colorfastness properties like rubbing, washing and light fastness of untreated and treated dyed fabric samples were measured using AATCC 08, AATCC 61 (2A) and AATCC 16, respectively. The color strength of these dyed fabric samples was determined by K/S value for comparison.

Application of a novel rGO-CuFeS2 composite catalyst conjugated to microwave irradiation for ultra-fast real textile wastewater treatment

The disposal of wastewater containing large amounts of dyes is a public health and environmental problem, due to its toxicity into the aquatic biota, the reduction in sunlight penetration, which consequently interference in photosynthetic activity. In the present study a new composite, based on the heterojunction of reduced graphene oxide (rGO) and chalcopyrite (CuFeS2), was developed to treat a real textile wastewater (RW). The efficiency of the composite assisted by microwave irradiation was evaluated to catalyze the decolorization and degradation of RW containing a high concentration of the azo Direct Black 22 (DB22). A small amount (0.5 w/w%) of rGO on CuFeS2 was enough to uplift the efficiency of decolorization to 74 % of DB22 and 97 % TOC in the RW, only in the first min of treatment, and 97 % and 99 %, respectively, at 6 min. The improvement in catalytic activity can be attributed to the dipolar polarization effect, hot spots and the generation of hydroxyl radicals. Additionally, a synergistic effect between the composite and microwave irradiation, assisted by hydrogen peroxide, reduced the RW phytotoxicity, improving the radicle length of Lactuca sativa three times (from 0.87 cm to 2.65 cm with the application of a single minute of treatment). The reduction in phytotoxicity led to an increase in the germination percentage from 36 % to 53 %. Finally, the use of MW irradiation coupled to a novel rGO-CuFeS2 composite, in presence of H2O2 under acid medium, provides a feasible and highly rapid method to treat RW, reducing its phytotoxicity.Capsule: A novel rGO-CuFeS2 catalyst was developed and applied together with microwave irradiation for an ultra-fast degradation treatment (6 min) in real textile wastewater.

Herbul black henna (hair dye) causes cardiovascular defects in zebrafish (Danio rerio) embryo model.

Herbul black henna (hair dye) have been widely used as cosmetic agents to temporarily change the color of hair. Their use was tremendously increased in the past decade. Especially, hair dye containing paraphenylenediamine (PPD) is extensively used globally because of its abundance and low cost. PPD, one of the main chemicals in hair dye, is known as a toxin. Hair dye has various adverse effects, including negative impacts on human health, especially during pregnancy and on aquatic environment. Although a large amount of dyes has been released into the environment, studies on environmental toxicity of these substances are still poorly understood. Hence, the main objective of this study is to evaluate the potential cardiovascular toxicological effects of hair dye on zebrafish (Danio rerio) embryo as a model. After exposing zebrafish embryos to various concentrations (100, 200, 300, 400, 500, and 600μM), their cardiotoxicity and other teratogenic effects were examined for various exposure periods ranged from 24 to 96hpf. As a result, the tested embryos could not survive over intervals of 48h after 72 and 96hpf at higher concentrations (300, 400, 500, and 600μM), except the lower concentration cases (100 and 200μM) some embryos were survived, respectively. However, hair dye increases mortality and decreases yolk stalk length, heart rate and severely affects heart looping in zebrafish embryos. In addition, the dye was observed to induce cardiovascular defects in transgenic Tg (fli1a:EGFP) and Tg (flk1:EGFP) zebrafish embryos at environmentally realistic dye concentrations. However, further study using bioassays is fundamentally required to predict the toxicity of hair dyes, aside from providing the information on their safe levels for living organisms. Therefore, the present results would be vital for the ecological risk assessment of hair dye, particularly for freshwater aquatic ecosystem and human health.

HETEROGENEOUS ELECTRO FENTON PROCESS FOR TEXTILE WASTEWATER TREATMENT: APPLICATION OF Fe3O4-Mn3O4 AS A CATALYST

To produce quality textile products, many stable synthetic dyes are invented. However, textile wastewater discharged into the environment contains a large amount of dyes which are bio-recalcitrants and stable to heat and solar radiation. These toxic contaminants impact negatively the environment for a long time and poison plants, animals, and human. In this study, Heterogeneous Electro Fenton process with Fe3O4-Mn3O4 as a catalyst was used for textile wastewater treatment. Graphite electrodes were chosen for their stability and good conductivity. Three operating factors greatly affected the removal efficiency are current density, pH and catalyst dosage. Response surface methodology was applied to find empirical mathematical models for these factors, then find an accordant operating condition for treatment which provides high removal efficiency and low operating cost. Investigated ranges scaled in previous studies were: current density (10 – 20 mA/cm2), pH (3 – 5), and catalyst dosage (0.5 – 1.5 g/l). At current density of 17.03 mA/cm2, pH of 3.77, catalyst dosage of 1.17 g/l, the treatment reached its optimum condition, COD and Color removal efficiencies were 93.3 % and 99.2 %, respectively, where COD and Color values in the effluent are 56 mg/l and 16 Pt-Co.

HETEROGENEOUS ELECTRO FENTON PROCESS FOR TEXTILE WASTEWATER TREATMENT: APPLICATION OF Fe3O4-Mn3O4 AS A CATALYST

To produce quality textile products, many stable synthetic dyes are invented. However, textile wastewater discharged into the environment contains a large amount of dyes which are bio-recalcitrants and stable to heat and solar radiation. These toxic contaminants impact negatively the environment for a long time and poison plants, animals, and human. In this study, Heterogeneous Electro Fenton process with Fe3O4-Mn3O4 as a catalyst was used for textile wastewater treatment. Graphite electrodes were chosen for their stability and good conductivity. Three operating factors greatly affected the removal efficiency are current density, pH and catalyst dosage. Response surface methodology was applied to find empirical mathematical models for these factors, then find an accordant operating condition for treatment which provides high removal efficiency and low operating cost. Investigated ranges scaled in previous studies were: current density (10 – 20 mA/cm2), pH (3 – 5), and catalyst dosage (0.5 – 1.5 g/l). At current density of 17.03 mA/cm2, pH of 3.77, catalyst dosage of 1.17 g/l, the treatment reached its optimum condition, COD and Color removal efficiencies were 93.3 % and 99.2 %, respectively, where COD and Color values in the effluent are 56 mg/l and 16 Pt-Co.

Dyes adsorption using clay and modified clay: A review

The effective use of the sorption properties of different clays as sorbents for the removal of dyes from wastewater has currently received much attention because of the eco-friendly nature of clay materials. Dyes are complex class of organic compound having wide range of applications in textile and food industries and a large amount of dyes are wasted, which get mixed in natural water resources. Mixing of dyes in water resources must be prohibited for the safety of natural ecosystem. The adsorbents (natural and modified) have been successfully used for the adsorption of dyes form wastewater. This review article highlights the importance of clay (raw and modified) as an adsorbent for the adsorption of dyes from textile wastewater. Appropriate conditions for clay-dye system and adsorption capacities of a variety of clays are presented and sorption process is critically analyzed. Studies reported the clays as an adsorbent from 2004 to 2016 are included and different properties for the utilization of clay and clay-based adsorbents are discussed. Based on studies, it was found that the clays (natural and modified) are affective adsorbents for the purification of wastewater containing dyes.

Nickel-Cobalt Layered Double Hydroxides for Photocatalytic Degradation under Visible Light Irradiation

As large amount of dye has been discharged as wastewater and infiltrated into our water system, it is now affecting the aquatic life due to its carcinogenic nature. Although heterogenous photocatalytic process is found effective in mineralizing these organic pollutants into less harmful one through light irradiation, the most often explored TiO2 is active only under UV light, thus limits its real application such photocatalyst in environmental remediation. A new class materials with hydrotalcite like structure, layered double hydroxides (LDH) has been recently explored for their superior photocatalytic degradation property as their anionic intercalating layer boosts their absorption capabilities, thus yielding high active surface area for photo-degradation to proceed. Despite their band gap tunability, chemical versatility and high reproducibility in large quantities, they suffer from poor control over particles size and morphology. Here in this paper, three different Nickel-Cobalt LDH morphologies are uniformly produced by utilizing a facile and economical synthesis method and by adjusting the precursor, ammonium fluoride. It is shown that NH4F can act as a structural-mediating agent that transforms 1D to 2D structure as well as a crystal forming agent that boosts the photocatalyst’s crystallinity, which would essentially enhance its photocatalytic methyl orange degradation for almost 2-fold than those of poor crystallinity. In short, this paper demonstrates a facile control of morphology and crystallinity of LDH for better photocatalysis under visible light irradiation.

Photocatalysis in a packed bed: Degradation of organic dyes by immobilized silver nanoparticles

Complete photocatalytic degradation of methyl orange, methylene blue and rhodamine chloride was accomplished using immobilized silver nanoparticles as catalysts and tethered calix[7]hydroquinone molecules as nano-reactors. The nanoparticles were immobilized on quartz beads that were assembled in a packed bed configuration. The large interfacial area afforded by the packed bed geometry, presentation of the nanoparticles as a single, tethered layer, and the optically transparent packing material facilitated intimate interaction between the catalyst, dye solution and radiation. The degradation was accomplished using either UV or visible radiation and the nanoparticles displayed self-cleaning and anti-poisoning properties thereby demonstrating excellent durability and catalytic efficiency. The single-layer coverage of Ag nanoparticles facilitates use of very small amounts of the photocatalyst for degradation of relatively large amounts of dye. The method addresses multiple issues that constrain scale-up of photocatalytic systems that deploy nanoparticles as catalysts.

Biopolymer Stabilized Iron Sulphide Nanoparticles for Removal of Acid Black 1 Dye

India is one of the largest producer and exporter of dyestuff among developing countries. Large amount of dyes is lost in industrial effluents during production and industrial use. Persistence of dyes in the environment, their non-biodegradability and toxicity necessitate urgent steps to develop environment-friendly approaches to remove them from wastewaters. The present work describes attempts to use iron-based catalytic nanoparticles (NPs) for removal and degradation of Acid Black 1, one of the notoriously toxic dyes. A rapid screening assay was developed in order to select NPs possessing reducing properties. Methylene blue (MB) dye (0.1mg/L, 250µl) was exposed to different preparations of NPs (7mg) for 30 minute in a 96-well microtiter plate and read at 630 nm using an ELISA reader. Iron sulphide nanoparticles (FeSNPs) stabilized by a plant biopolymer (BP) could remove >95% MB and were selected for further studies. The FeSNPs could remove Acid Black 1 efficiently (73.8%) with specific dye removal capacity of 19.7 mg/g NPs. FeSNPs were immobilized in alginate beads (average diameter 3.45 mm) and packed in polypropylene columns (22.5 cm long, 3 cm i.d.) having bed volume of 42 ml. Acid black 1 solution (20 mg/L) was passed through the columns at predetermined flow rates in up-flow mode using peristaltic pump. The mass transfer kinetics were favourable at a flow rate of 2.2 ml/min (mass transfer coefficient 9.38X10-5 L.mg-1.min-1), and 120 bed volumes of the solution could be treated with efficiency exceeding 90%. Analysis of column effluent by UV-visible and FTIR spectroscopy revealed that removal of dye from solution was due to reductive degradation.

Evaluating Cellular Repair Potential - Lessons from Skeletal Muscle

The ability to repair disruptions in the plasma membrane is critical for maintaining cellular integrity and health; this is especially true for cells that routinely experience membrane damage as a result of activity such as skeletal muscle. Dysferlinopathies are a class of late onset muscle wasting diseases associated with the absence or truncation of the protein dysferlin. Dysferlin is postulated to have a role in membrane repair and the absence of dysferlin in both humans and animal models is associated with muscle damage. We are developing techniques to evaluate the repair potential of dysferlin null skeletal muscle fibers and myotubes using fluorescence assays of dye-leakage and calcium activity. In isolated muscle fibers or myotubes containing fluorescent dye and subjected to IR laser wounding, both the rate and duration of dye-leakage are measured by confocal microscopy. Upon wounding repair-competent fibers a “puff” of dye is released at the wound site and dye leakage ceases within 60 seconds. Under conditions where resealing is inhibited (i.e. low extracellular [Ca2+]) a large amount of dye is lost; leakage continues for >10 minutes. Changes in intracellular [Ca2+]free are measured using a combination of the calcium indicator dyes fluo-4 and Fura Red. Upon wounding, a rise in [Ca2+]free is observed at the wound site and either returns to the pre-wound level following successful resealing, or in the absence of resealing remains high and spreads through the entire fiber or mytube. Dysferlin null muscle, is repair competent but may differ in the developed calcium load, contractile response, and wounding threshold compared to dysferlin positive muscle. Since our overall goal is to develop interventions that boost cellular repair potential, quantifiable metrics of this complicated cellular process are required when testing the efficacy of repair-targeted treatments.

Production, Characterization and Treatment of Textile Effluents: A Critical Review

Textile industry is one of the major industries in the world that provide employment with no required special skills and play a major role in the economy of many countries. There are three different types of fibres used in the manufacture of various textile products: cellulose fibres, protein fibres and synthetic fibres. Each type of fibre is dyed with different types of dyes. Cellulose fibres are dyed using reactive dyes, direct dyes, napthol dyes and indigo dyes. Protein fibres are dyed using acid dyes and lanaset dyes. Synthetic fibres are dyed using disperse dyes, basic dyes and direct dyes. The textile industry utilizes various chemicals and large amount of water during the production process. About 200 L of water are used to produce 1 kg of textile. The water is mainly used for application of chemicals onto the fibres and rinsing of the final products. The waste water produced during this process contains large amount of dyes and chemicals containing trace metals such as Cr, As, Cu and Zn which are capable of harming the environment and human health. The textile waste water can cause haemorrhage, ulceration of skin, nausea, skin irritation and dermatitis. The chemicals present in the water block the sunlight and increase the biological oxygen demand thereby inhibiting photosynthesis and reoxygenation process. The effluent water discharged from the textile industries undergoes various physio-chemical processes such as flocculation, coagulation and ozonation followed by biological treatments for the removal of nitrogen, organics, phosphorous and metal. The whole treatment process involves three steps: primary treatment, secondary treatment and tertiary treatment. The primary treatment involves removal of suspended solids, most of the oil and grease and gritty materials. The secondary treatment is carried out using microorganisms under aerobic or anaerobic conditions and involves the reduction of BOD, phenol and remaining oil in the water and control of color. The tertiary treatment involves the use of electrodialysis, reverse osmosis and ion exchange to remove the final contaminants in the wastewater. The major disadvantages of using the biological process are that the presence of toxic metals in the effluent prevents efficient growth of microorganisms and the process requires a long retention time. The advanced oxidation processes is gaining attention in the recent days due to the ability to treat almost all the solid components in the textile effluents. The photo oxidation of the effluents is carried out using H2O2, combination of H2O2 and UV and Combination of TiO2 and UV. Advanced oxidation process generates low waste and uses hydroxyl radicals (OHA¢Â—) as their main oxidative power. The hydroxyl radicals (OHA¢Â—) are produced by chemical, electrical, mechanical or radiation energy and therefore advanced oxidation processes are classified under chemical, photochemical, catalytic, photocatalytic, mechanical and electrical processes. The effluents treated with advanced oxidation process were found to reduce 70-80% COD when compared to 30-45% reduction in biological treatment.

Removal of Neutral Red from Aqueous Solution by Pretreated <i>Penicillium Sp</i>

The biosorption of neutral red, from aqueous solutions by Penicilium sp. biomass was studied in a batch system with respect to pretreatment methods, contact time, pH, initial dye concentration and temperature. The NaHCO3- treated biomass exhibited maximum dye uptake at pH 5-6. A larger amount of dye was removed by the pretreated biomass in the first 10 min of contact time and the equilibrium was established in 60 min for 50 mg/L of initial dye concentration. The optimum biosorption temperature was determined as 40 °C. Biosorption played main role in dye removal from aqueous solution in this study. The results indicate that the pretreated Penicilium sp. biomass can be used as an effective biosorbent to remove neutral red from aqueous solution.

The role of transition metal cations in dyeing of fabrics made from synthetic fibres

The use of d-metal cations in dyeing polyester fabric with dark blue K increases the dyeability to 350%. Use of VO2+, Fe2+, and Cu2+ cations is most effective. It is hypothesized that d-metal cations increase the number of active sites due to vacant atomic orbitals on the valence level so that the polyester fibre can sorb a larger amount of dye. The use of d-metal cations in dyeing polyester fabric increases the resistance of the color to external physicochemical effects.

Wastewater treatment of reactive dyestuffs by ozonation in a semi-batch reactor

Water is quickly becoming both scarce and very expensive. Thus, it has become necessary for every industry to examine proposals for the purification and re-use of their wastewater and effluent streams. The Textile industry is one of the largest industrial consumers of water. Predominantly, wastewater from textile industry contains large amounts of dye and dyeing agents, as well as mordant and sizing agents. Current advanced oxidation processes (AOPs) which include ozone, photochemical and photo catalytic oxidation are techniques used for the treatment of such wastewater. Although AOPs are relatively expensive, they appear to be the most likely candidates for full-scale dye house effluent decolouration.The ozonation of wastewater containing four different textile reactive dyestuffs in a semi-batch reactor have been studied. Various ozonation conditions – ozone dose, ozone consumption efficiency, etc. – were explored and studied for these various types of dyestuffs. The mass transfer coefficient of ozone in water and its relationship to the ozone efficiency was studied. Pseudo-first order decolouration rate constants for all dyestuffs were determined experimentally.

Evidence of Degradation of Triarylmethine Dyes on Texas Vermiculite

AbstractSynthetic dyes in industrial effluents pose a significant risk to human health and the environment, so much effort has been expended to degrade them using various methods, including the use of clay minerals as catalysts. The purpose of this study was to advance understanding of the mechanisms for clay-catalyzed degradation of crystal violet (CV) and other triarylmethine dyes using three different vermiculite clays (Llano, Texas, VTx-1; Ojen, OV; and Russian, RV), a montmorillonite (SWy-1), and a Spanish sepiolite (SEP). While OV, RV, SWy-1, and SEP showed almost no activity with respect to dye degradation, VTx-1 caused complete removal of the dye from solution up to the equivalent of 200% of the cation exchange capacity of the clay. While large amounts of dye were removed from the solution, no change in basal spacing was observed by X-ray diffraction. The kinetics of removal of CV from solution began after a lag period of >10 days in a process that can be described by pseudo-second order kinetics. By comparison, adsorption of CV onto SWy-1 and SEP was immediate, without any lag period. Sonication treatment of the VTx-1 vermiculite suspension caused the CV removal process to begin immediately. Fourier-transform infrared measurements of adsorption of CV on clays revealed that for the OV and RV vermiculites, SEP sepiolite, and SWy-1 montmorillonite the spectra were similar to the original dye; the spectra of the VTx-1-dye differed considerably, however, exhibiting vibrations of methylene groups (—CH2—) which were not present in the CV molecule. The significant changes in the IR spectrum indicated that CV underwent degradation on the surface of the VTx-1 vermiculite. Carbon-content analysis led to the conclusion that degradation products remained bound to the clay. Similar effects were observed for two other triarylmethine dyes (malachite green and methyl green) added to VTx-1, indicated that it may, therefore, be considered suitable as a sorbent to remove and decompose such dyes from industrial effluents. Pretreatment by sonication would remove the need for long incubation times.

水溶性光感受性物質NPe6を用いた光化学療法の眼科応用の可能性

The authors evaluated potential of photodynamic therapy with a new photosensitizer, mono-L-aspartyl chlorin e6 (NPe6) that tissue uptake and clearance are rapid. Firstly, NPe6 solution was exposed to diode laser at 664nm that fits to maximum absorption of NPe6. Immediately after laser exposure, these solutions were subjected to electron spin resonance (ESR) to detect generation of activated oxygen species. With ESR, signals of O2, OH, and 1O2 were detected on NPe6 solution. Contrary to this, signals of O2 and OH dissipated when dissolved with superoxide dismutase. Fundi of pigmented rabbits were then irradiated to diode laser after administration of NPe6. Histopathologically, there showed necrosis of endothelial cells and vascular occlusion in choroid, especially in choriocapillaris. Retinal pigment epithelial cells were also injured. In contrast, sensory retina was approximately preserved even with a large amount of dye. A new combination of NPe6 and diode laser at 664nm enables us to occlude choroidal vessels efficiently by generating various activated oxygens. This fact proposed potential of photodynamic therapy with NPe6 in treating retinochoroidal involvement.