Wastewater chemical contaminants: remediation by advanced oxidation processes

Antimicrobial Photodynamic Approach in the Inactivation of Viruses in Wastewater: Influence of Alternative Adjuvants

Pathogenic viruses are frequently present in marine and estuarine waters, due to poor wastewater (WW) treatments, which consequently affect water quality and human health. Chlorination, one of the most common methods used to ensure microbiological safety in tertiarily treated effluents, may lead to the formation of toxic chemical disinfection by-products on reaction with organic matter present in the effluents. Antimicrobial photodynamic therapy (aPDT) can be a promising disinfecting approach for the inactivation of pathogens, without the formation of known toxic by-products. Additionally, some studies have reported the potentiator effect on aPDT of some compounds, such as potassium iodide (KI) and hydrogen peroxide (H2O2). In the present study, the aPDT efficiency of a PS formulation constituted of five cationic porphyrins (Form) in the inactivation of E. coli T4-like bacteriophage, a model of mammalian viruses, in different aqueous matrices with different organic matter content, was evaluated. Photoinactivation studies were performed at different concentrations of Form and in the presence of the adjuvants KI and H2O2. The results showed that the efficiency of bacteriophage photoinactivation is correlated with the Form concentration, the amount of the organic matter in WW, and the adjuvant type. Form can be an effective alternative to controlling viruses in WW, particularly if combined with H2O2, allowing to significantly reduce PS concentration and treatment time. When combined with KI, the Form is less effective in inactivating T4-like bacteriophage in WW.

Application of TiO2-Based Photocatalysts to Antibiotics Degradation: Cases of Sulfamethoxazole, Trimethoprim and Ciprofloxacin

The extensive application of antibiotics in human and veterinary medicine has led to their widespread occurrence in a natural aquatic environment. Global health crisis is associated with the fast development of antimicrobial resistance, as more and more infectious diseases cannot be treated more than once. Sulfamethoxazole, trimethoprim and ciprofloxacin are the most commonly detected antibiotics in water systems worldwide. The persistent and toxic nature of these antibiotics makes their elimination by conventional treatment methods at wastewater treatment plants almost impossible. The application of advanced oxidation processes and heterogeneous photocatalysis over TiO2-based materials is a promising solution. This highly efficient technology has the potential to be sustainable, cost-efficient and energy-efficient. A comprehensive review on the application of various TiO2-based photocatalysts for the degradation of sulfamethoxazole, trimethoprim and ciprofloxacin is focused on highlighting their photocatalytic performance under various reaction conditions (different amounts of pollutant and photocatalyst, pH, light source, reaction media, presence of inorganic ions, natural organic matter, oxidants). Mineralization efficiency and ecotoxicity of final products have been also considered. Further research needs have been presented based on the literature findings. Among them, design and development of highly efficient under sunlight, stable, recyclable and cost-effective TiO2-based materials; usage of real wastewaters for photocatalytic tests; and compulsory assessment of products ecotoxicity are the most important research tasks in order to meet requirements for industrial application.

Evaluation and comparison of advanced oxidation processes for the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D): a review

Organochlorine pesticides have generated public concern worldwide because of their toxicity to human health and the environment, even at low concentrations, and their persistence, being mostly nonbiodegradable. The use of 2,4-dichlorophenoxyacetic acid (2,4-D) has increased in recent decades, causing severe water contamination. Several treatments have been developed to degrade 2,4-D. This manuscript presents an overview of the physicochemical characteristics, uses, regulations, environmental and human health impacts of 2,4-D, and different advanced oxidation processes (AOPs) to degrade this organic compound, evaluating and comparing operation conditions, efficiencies, and intermediaries. Based on this review, 2,4-D degradation is highly efficient in ozonation (system O₃/plasma, 99.8% in 30 min). Photocatalytic, photo-Fenton, and electrochemical processes have the optimal efficiencies of degradation and mineralization: 97%/79.67% (blue TiO₂ nanotube arrays//UV), 100%/98% (Fe²⁺/H₂O₂/UV), and 100%/84.3% (MI-meso SnO₂), respectively. The ozonation and electrochemical processes show high degradation efficiencies, but energy costs are also high, and photocatalysis is more expensive with a separation treatment used to recover the catalyst in the solution. The Fenton process is a viable economic-environmental option, but degradation efficiencies are often low (50-70%); however, they are increased when solar UV radiation is used (90-100%). AOPs are promising technologies for the degradation of organic pollutants in real wastewater, so evaluating their strengths and weaknesses is expected to help select viable operational conditions and obtain optimal efficiencies.

Kiwifruit bacterial canker: an integrative view focused on biocontrol strategies

Phage-based biocontrol strategies can be an effective alternative to control Psa-induced bacterial canker of kiwifruit. The global production of kiwifruit has been seriously affected by Pseudomonas syringae pv. actinidiae (Psa) over the last decade. Psa damages both Actinidia chinensis var. deliciosa (green kiwifruit) but specially the susceptible Actinidia chinensis var. chinensis (gold kiwifruit), resulting in severe economic losses. Treatments for Psa infections currently available are scarce, involving frequent spraying of the kiwifruit plant orchards with copper products. However, copper products should be avoided since they are highly toxic and lead to the development of bacterial resistance to this metal. Antibiotics are also used in some countries, but bacterial resistance to antibiotics is a serious worldwide problem. Therefore, it is essential to develop new approaches for sustainable agriculture production, avoiding the emergence of resistant Psa bacterial strains. Attempts to develop and establish highly accurate approaches to combat and prevent the occurrence of bacterial canker in kiwifruit plants are currently under study, using specific viruses of bacteria (bacteriophages, or phages) to eliminate the Psa. This review discusses the characteristics of Psa-induced kiwifruit canker, Psa transmission pathways, prevention and control, phage-based biocontrol strategies as a new approach to control Psa in kiwifruit orchards and its advantages over other therapies, together with potential ways to bypass phage inactivation by abiotic factors.

Current and Emerging Adsorbent Technologies for Wastewater Treatment: Trends, Limitations, and Environmental Implications

Wastewater generation and treatment is an ever-increasing concern in the current century due to increased urbanization and industrialization. To tackle the situation of increasing environmental hazards, numerous wastewater treatment approaches are used—i.e., physical, chemical, and biological (primary to tertiary treatment) methods. Various treatment techniques being used have the risks of producing secondary pollutants. The most promising technique is the use of different materials as adsorbents that have a higher efficacy in treating wastewater, with a minimal production of secondary pollutants. Biosorption is a key process that is highly efficient and cost-effective. This method majorly uses the adsorption process/mechanism for toxicant removal from wastewater. This review elaborates the major agricultural and non-agricultural materials-based sorbents that have been used with their possible mechanisms of pollutant removal. Moreover, this creates a better understanding of how the efficacy of these sorbents can be enhanced by modification or treatments with other substances. This review also explains the re-usability and mechanisms of the used adsorbents and/or their disposal in a safe and environmentally friendly way, along with highlighting the major research gaps and potential future research directions. Additionally, the cost benefit ratio of adsorbents is elucidated.

Recent advances in the adsorptive remediation of wastewater using two-dimensional transition metal carbides (MXenes): a review

MXenes, since their discovery in 2011, have garnered significant research attention for a variety of applications due to their exciting physico-chemical properties.

Catalytic enrichment of plasma with hydroxyl radicals in the aqueous phase at room temperature

Iron oxide on mesoporous silica gave a synergy with plasma jet for HO˙ radical production at neutral pH.

Manganese-Doped Zinc Oxide Nanostructures as Potential Scaffold for Photocatalytic and Fluorescence Sensing Applications

Herein, we report the photocatalytic and fluorescence sensing applications of manganese-doped zinc oxide nanostructures synthesized by a solution combustion technique, using zinc nitrate as an oxidizer and urea as a fuel. The synthesized Mn-doped ZnO nanostructures have been analyzed in terms of their surface morphology, phase composition, elemental analysis, and optical properties with the help of scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and UV-Visible (UV-Vis) spectroscopy. A careful observation of the SEM micrograph reveals that the synthesized material was porous and grown in very high density. Due to a well-defined porous structure, the Mn-doped ZnO nanostructures can be used for the detection of ciprofloxacin, which was found to exhibit a significantly low limit of detection (LOD) value i.e., 10.05 µM. The synthesized Mn-doped ZnO nanostructures have been further analyzed for interfering studies, which reveals that the synthesized sensor material possesses very good selectivity toward ciprofloxacin, as it detects selectively even in the presence of other molecules. The synthesized Mn-doped ZnO nanostructures have been further analyzed for the photodegradation of methyl orange (MO) dye. The experimental results reveal that Mn-doped ZnO behaves as an efficient photocatalyst. The 85% degradation of MO has been achieved in 75 min using 0.15 g of Mn-doped ZnO nanostructures. The observed results clearly confirmed that the synthesized Mn-dopedZnO nanostructures are a potential scaffold for the fabrication of sensitive and robust chemical sensors as well as an efficient photocatalyst.

Treatment Processes for Microbial Resistance Mitigation: The Technological Contribution to Tackle the Problem of Antibiotic Resistance

Advances generated in medicine, science, and technology have contributed to a better quality of life in recent years; however, antimicrobial resistance has also benefited from these advances, creating various environmental and health problems. Several determinants may explain the problem of antimicrobial resistance, such as wastewater treatment plants that represent a powerful agent for the promotion of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARG), and are an important factor in mitigating the problem. This article focuses on reviewing current technologies for ARB and ARG removal treatments, which include disinfection, constructed wetlands, advanced oxidation processes (AOP), anaerobic, aerobic, or combined treatments, and nanomaterial-based treatments. Some of these technologies are highly intensive, such as AOP; however, other technologies require long treatment times or high doses of oxidizing agents. From this review, it can be concluded that treatment technologies must be significantly enhanced before the environmental and heath problems associated with antimicrobial resistance can be effectively solved. In either case, it is necessary to achieve total removal of bacteria and genes to avoid the possibility of regrowth given by the favorable environmental conditions at treatment plant facilities.

Unravelling the Environmental Application of Biochar as Low-Cost Biosorbent: A Review

In this age, a key target for enhancing the competitiveness of the chemical, environmental and biotechnology industries is to manufacture high-value products more efficiently and especially with significantly reduced environmental impact. Under this premise, the conversion of biomass waste to a high-value added product, biochar, is an interesting approach under the circular economy principles. Thus, the improvements in the biochar production and its new and innovative uses are hot points of interest, which are the focus of vast efforts of the scientific community. Biochar has been recognized as a material of great potential, and its use as an adsorbent is becoming a reliable strategy for the removal of pollutants of different streams, according to its high adsorption capacity and potential to eliminate recalcitrant compounds. In this review, a succinct overview of current actions developed to improve the adsorption capability of biochar, mainly of heavy metal and organic pollutants (dyes, pharmaceuticals and personal care products), is summarized and discussed, and the principal adsorption mechanisms are described. The feedstock and the production procedure are revealed as key factors that provide the appropriate physicochemical characteristics for the good performance of biochar as an adsorbent. In addition, the modification of the biochar by the different described approaches proved their feasibility and became a good strategy for the design of selective adsorbents. In the last part of this review, the novel prospects in the regeneration of the biochar are presented in order to achieve a clean technology for alleviating the water pollution challenge.

Anticorrosion Coated Stainless Steel as Durable Support for C-N-TiO2 Photo Catalyst Layer

The development of durable photocatalytic supports resistant in harsh environment has become challenging in advanced oxidation processes (AOPs) focusing on water and wastewater remediation. In this study, stainless steel (SS), SS/Ti (N,O) and SS/Cr-N/Cr (N,O) anticorrosion layers on SS meshes were dip-coated with sol gel synthesised C-N-TiO₂ photo catalysts pyrolysed at 350 °C for 105 min, using a heating rate of 50 °C/min under N₂ gas. The supported C-N-TiO₂ films were characterised by scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy. The results showed that C-N-TiO₂ was successfully deposited on anticorrosion coated SS supports and had different morphologies. The amorphous C and TiO₂ were predominant in C-N-TiO₂ over anatase and rutile phases on the surface of SS and anticorrosion supports. The C-N-TiO₂ coated films showed enhanced photocatalytic activity for the decolouration of O.II dye under both solar and UV radiations. The fabricated C-N-TiO₂ films showed significant antibacterial activities in the dark as well as in visible light. Herein, we demonstrate that SS/Ti(N,O) and SS/Cr-N/Cr(N,O) anticorrosion coatings are adequate photocatalytic and corrosion resistant supports. The C-N-TiO₂ photo catalytic coatings can be used for water and wastewater decontamination of pollutants and microbes.

3D Printed Hydrogel-Based Sensors for Quantifying UV Exposure

Exposure to excessive ultraviolet (UV) radiation can have detrimental effects on human health. Inexpensive easy-to-use sensors for monitoring UV radiation can allow broad-scale assessment of UV exposure, but their implementation requires technology that enables rapid and affordable manufacturing of these sensors on a large scale. Herein, we report a novel three-dimensional (3D) printing procedure and printable ink composition that produce robust, flexible, and wearable UV sensors. To fabricate the sensors, a color-changing hydrogel ink was first developed from which standalone constructs were 3D printed. The ink contains alginate, gelatin, photoactive titanium dioxide nanoparticles, and dyes (methyl orange, methylene blue, and malachite green) in which the nanoparticles are used to initiate photocatalytic degradation of dyes, leading to discoloration of the dye. The sensors resemble a color-changing tattoo that loses color upon exposure to UV. The viscosity and ink composition were optimized to achieve printability and tune the mechanical properties (e.g., modulus, hardness) of the sensors. The optimized procedure enabled the one-step fabrication of mechanically stable sensors that can effectively measure outdoor sun exposure by quantifying the decrease in color, visible to the naked eye. Apart from being used as wearable sensors, these sensors have the potential to be used along with UV-based workspace sterilizing devices to ensure that surfaces have been efficiently exposed to UV. The sensors are inexpensive, stable, extremely robust, biodegradable, and easy to use. The tunability, biocompatibility, and printability of the ink offer excellent potential for developing advanced 3D printing methods that, in addition to UV sensors, can be applied more broadly to fabricate other sensing technologies for a variety of other applications.

Complementary behavior of doping and loading in Ag/C-ZnTa2O6 for efficient visible-light photocatalytic redox towards broad wastewater remediation

This work reports on the simple fabrication of a silver loaded and carbon doped zinc tantalate (Ag/C-ZnTa₂O₆) photocatalyst with visible light photocatalytic activity toward broad wastewater remediation, including high photo-reduction of Cr(vi) (98.4% in 210 min), excellent photo-oxidation of tetracycline hydrochloride (94.7% in 210 min), and superior photo-degradation of multiple dyes (>99.0% within 210 min). The optimal photocatalytic performance of Ag/C-ZnTa₂O₆ is mainly due to the excellent visible light absorption capacity and superior electron-hole separation efficiency, which is ascribed to the complementary behavior between carbon doping and silver loading. Particularly, the generation of defects due to C-doping is greatly inhibited by Ag-loading, and the SPR effect of Ag nanoparticles is enhanced due to the obstruction of Ag⁺ by C doping.

Antimicrobial Photodynamic Therapy in the Control of Pseudomonas syringae pv. actinidiae Transmission by Kiwifruit Pollen

Pseudomonas syringae pv. actinidiae (Psa) is a phytopathogen responsible for bacterial canker in kiwifruit plants and can be disseminated through pollen. This study aimed to evaluate the effectiveness of antimicrobial photodynamic therapy (aPDT) in the inactivation of Psa on kiwifruit pollen using New Methylene Blue (NMB) and Methylene Blue (MB) in the presence/absence of potassium iodide (KI). Pollen germination assays were also performed to evaluate if it was affected by aPDT. Higher reduction of Psa was achieved using NMB (5.0 μM) combined with KI (100 mM) in vitro (ca. 8 log CFU mL-1 after 90 min of irradiation), while NMB alone promoted a lower reduction (3.7 log CFU mL-1). The most efficient NMB concentration with KI was used to study the photodynamic efficiency of MB (5.0 μM). MB with KI photo-inactivated Psa more efficiently than NMB, causing the same bacterial reduction (ca. 8 log CFU mL-1) in half the irradiation time (45 min). Therefore, MB was selected for the subsequent ex vivo aPDT assays in pollen. Almost all the Psa cells added artificially to the pollen (3.2 log CFU mL-1) were photo-inactivated (3.1 log CFU mL-1), whereas aPDT had a low effect on pollen natural microorganisms. When KI was added, a significant increase in aPDT effectiveness was observed (4.5 log CFU mL-1). No negative effects were observed in the pollen germination after aPDT. The results show aPDT is an effective and safe method to Psa inactivation on kiwifruit pollen, and MB use is a promising alternative in the control of Psa transmission.

Synthesis of Magnetic Fe3O4/ZnWO4 and Fe3O4/ZnWO4/CeVO4 Nanoparticles: The Photocatalytic Effects on Organic Pollutants upon Irradiation with UV-Vis Light

Magnetic Fe3O4/ZnWO4 and Fe3O4/ZnWO4/CeVO4 nanoparticles with different molar ratios of CeVO4 to other inorganic components were synthesized through co-precipitation with a sonochemical-assisted method. X-ray diffraction, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, vibrating sample magnetometry, and scanning electron microscopy (SEM) methods were used for the physico–chemical characterization of the obtained nanoparticles. As shown in the SEM images, the average sizes of the Fe3O4/ZnWO4 and Fe3O4/ZnWO4/CeVO4 nanoparticles that formed aggregates were approximately 50–70 nm and 80–100 nm, respectively. The photocatalytic performance of these nanoparticles was examined by measuring methylene blue degradation under visible light (assisted by H2O2). The sample with a mass ratio of 1:2:1 (Fe3O4/ZnWO4/CeVO4, S4) exhibited optimal photocatalytic performance, and thus this sample was subsequently used for the photodegradation of different organic pollutants upon irradiation with ultraviolet (UV) and visible light. Approximately 90% and 70% degradation of methyl violet and methylene blue, respectively, was observed after visible light irradiation. Additionally, the mechanism of the photocatalytic reaction was investigated by measuring ˙OH release under UV light in a system with terephthalic acid and by measuring the release of ˙O2−, ˙OH, and hole scavengers.

Quantitative structure-property relationship of the photoelectrochemical oxidation of phenolic pollutants at modified nanoporous titanium oxide using supervised machine learning

Here we report on an advanced photoelectrochemical (PEC) oxidation of 22 phenolic pollutants based on modified nanoporous TiO2, which was directly grown on a titanium substrate electrochemically. Their degradation rate constants were experimentally determined and their physicochemical properties were computaionally calculated. The quantitative structure-property relationship (QSPR) was elucidated by employing multiple linear regression (MLR) method. A supervised machine learning approach was employed to build QSPR models. The high predictive abilities of the QSPR model were validated via leave-one-out (LOO) method and a strict regimen of statistical validation tests. The significant descriptors identified in the QSPR Model for the phenolic compounds were also assessed using a typical dye pollutant Rhodamine B, further confirming the high effectiveness and predictability of the optimized model. Our study has shown that the integrated effect of the structural, hydrophobic and topological properties along with electronic property should be considered in order to design an efficient PEC catalytic approach for environmental applications.

Feasibility of the use of Lentinula edodes mycelium in terbinafine remediation

A detailed understanding of the fate of xenobiotics introduced into the environment and the mechanisms involved in their biotransformation, biodegradation, and biosorption is essential to improve the efficiency of remediation techniques. Mycoremediation is a form of bioremediation technique that has become increasingly popular in recent years as fungi are known to produce various effective extracellular enzymes that have the potential to neutralize a wide variety of xenobiotics released into the environment. Hence, mycoremediation appears to be a promising technique for the removal of a wide array of toxins and pharmaceutical residues from a damaged environment and wastewater. This study primarily aimed to investigate whether white-rot fungus (Lentinula edodes) can be utilized for the bioremediation of common antifungal agent terbinafine, which is mainly available in the market as powder or cream. The cultures of L. edodes were cultivated in the medium containing terbinafine powder or terbinafine 1% cream, each at a final concentration of 0.1 mg mL^-1. The addition of terbinafine in powder form have a negative effect on biomass growth (p < 0.05). The total amount of terbinafine in the dry weight of mycelium after culture was estimated to be 7.63 ± 0.45 mg and 12.52 ± 2.46 mg for powder and cream samples, respectively. In addition, there were no traces of terbinafine in any of the samples of medium used for culturing L. edodes after the experimental duration period. The biodegradation products of terbinafine were identified for the first time using UPLC/MS/MS. The biodegradation of terbinafine resulted in the loss of 1-naphthylmethanol, which occurred via oxidative deamination, N-demethylation, or tert-butyl group hydroxylation. The results of the study demonstrate that L. edodes mycelium can be effectively used for the remediation of terbinafine.

Facile one-pot synthesis of heterostructure SnO2/ZnO photocatalyst for enhanced photocatalytic degradation of organic dye

In this work, heterostructure SnO₂/ZnO nanocomposite photocatalyst was prepared by a straightforward one step polyol method.

Advanced Oxidation Processes for the Removal of Antibiotics from Water. An Overview

In this work, the application of advanced oxidation processes (AOPs) for the removal of antibiotics from water has been reviewed. The present concern about water has been exposed, and the main problems derived from the presence of emerging pollutants have been analyzed. Photolysis processes, ozone-based AOPs including ozonation, O3/UV, O3/H2O2, and O3/H2O2/UV, hydrogen peroxide-based methods (i.e., H2O2/UV, Fenton, Fenton-like, hetero-Fenton, and photo-Fenton), heterogeneous photocatalysis (TiO2/UV and TiO2/H2O2/UV systems), and sonochemical and electrooxidative AOPs have been reviewed. The main challenges and prospects of AOPs, as well as some recommendations for the improvement of AOPs aimed at the removal of antibiotics from wastewaters, are pointed out.

Water reclamation and reuse

Literature published in 2018 pertinent to water reclamation and reuse has been classified into five topics: safe reuse, treatment technologies, management, assessment, and case studies. Researches have been conducted to develop new technologies and improve conventional treatments for achieving sustainable wastewater reclamation, and increasing efforts have been made to facilitate safe water reuse. PRACTITIONER POINTS: The way of publicity greatly influences people's acceptance of water reuse and willingness to purchase produce irrigated with recycled water. Integrated process is the most commonly used treatment technology to reclaim water. There is a lack of local or regional regulatory and policy for sustainable water management.

Emerging pollutants-Part II: Treatment

Recently, emerging pollutants (EPs) have been frequently detected in urban wastewater, surface water, drinking water, and other water bodies. EPs mainly usually include pharmaceuticals and personal care products, endocrine-disrupting chemicals, antibiotic resistance genes, persistent organic pollutants, disinfection by-products, and other industrial chemicals. The potential threat of EPs to ecosystems and human health has attracted worldwide attention. Therefore, how to treat EPs in various water bodies has become one of the research priorities. In this paper, some research results on treatment of EPs published in 2018 were summarized. PRACTITIONER POINTS: At present, more attention has been paid to emerging pollutants (EPs), including pharmaceuticals and personal care products (PPCPs), endocrine-disrupting chemicals (EDCs), antibiotic resistance genes, persistent organic pollutants, disinfection by-products, etc. Existing EPs disposal technologies mainly include: engineered wetlands and natural systems, biological treatment, physical and physicochemical separation, chemical oxidation, catalysis, etc. This paper reviews some research results on the treatment technologies of EPs published in 2018.

Removal of Organic Pollution in the Water Environment

The development of civilization entails a growing demand for consumer goods. A side effect of the production and use of these materials is the production of solid waste and wastewater. Municipal and industrial wastewater usually contain a large amount of various organic compounds and are the main source of pollution of the aquatic environment with these substances. Therefore, the search for effective methods of wastewater and other polluted water treatment is an important element of caring for the natural environment. This Special Issue contains nine peer-review articles presenting research on the determination and removal of environmentally hazardous organic compounds from aqueous samples. The presented articles were categorized into three major fields: new approaches to the degradation of water pollutants, new methods of isolation and determination of the emerging organic contaminants (EOCs), and the occurrence of EOCs in the water environment. These articles present only selected issues from a very wide area, which is the removal of organic pollution in water environment, but can serve as important references for future studies.

Cobalt phthalocyanine-TiO2 nanocomposites for photocatalytic remediation of textile dyes under visible light irradiation

CoPc(COOH)[Formula: see text]-TiO[Formula: see text] nanocomposites to be used as efficient visible light photocatalysts were obtained by modifying TiO2 nanoparticles with cobalt(II) tetracarboxyphthalocyanine (CoPc(COOH)[Formula: see text]). The photocatalyst was then characterized by ultra-violet diffuse reflectance spectroscopy (UV-DRS), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The UV-DRS spectra showed that the absorbance spectrum of the modified catalyst was shifted to the visible region. Different textile dye solutions of Reactive Red 180, Acid Red 88 and Direct Orange 46 were efficiently degraded under visible light. Color removal rates were established to be 30%, 53% and 47% after 180 min for RR180, AR88 and DO46 dyes, respectively. The optimum catalyst concentration was determined to be 1 g/L of CoPc(COOH)[Formula: see text]-TiO[Formula: see text]. Development of the CoPc(COOH)[Formula: see text]-TiO[Formula: see text] nanocomposite photocatalyst enabled the utilization of visible light irradiation for efficient photodegradation of organic textile dye solutions.