Reactive Red Dye Research Articles

Metal oxide-doped polymer-based nanocomposite hydrogels: batch adsorption of reactive red dye from aqueous solutions

Metal oxide-doped polymer-based nanocomposite hydrogels: batch adsorption of reactive red dye from aqueous solutions

Fabrication of biopolymeric sheets using cellulose extracted from water hyacinth and its application studies for reactive red dye removal

Driven by the imperative need for sustainable and biodegradable materials, this study focuses on two pivotal aspects: cellulose extraction and dye removal. The alarming repercussions of non-biodegradable food packaging materials on health and the environment necessitate the exploration of viable alternatives. Herein, we embark on creating easily degradable biopolymer substitutes, achieved through innovative crafting of a biodegradable cellulose sheet sourced from extracted cellulose. Concurrently, the significant environmental and health hazards posed by textile industry discharge of wastewater laden with persistent dyes demand innovative treatment strategies. This study extensively investigated four distinct methods of cellulose extraction from water hyacinth, a complex aquatic weed. The functional groups, crystallinity index, thermal stability, thermal effects, and morphology of the extracted cellulose were characterized by FTIR, XRD, TGA, DSC, and SEM. This exploration yielded a notable outcome, as the most promising yield (39.4 ± 0.02% w/w) emerged using 2% sodium chlorite and 2% glacial acetic acid as bleaching agents, surpassing other methods. Building on this foundational cellulose extraction process, the extracted fibers were transformed into highly biodegradable cellulose sheets, outlining conventional packaging materials. Moreover, these cellulose sheets exhibit exceptional efficacy in adsorbing reactive red dye, with the adsorption capacity of 71.43 mg/g by following pseudo-second kinetics. This study establishes an economically viable avenue for repurposing challenging aquatic weeds into commercially valuable biopolymers. The potential of these sheets for dye removal, coupled with their innate biodegradability, opens auspicious avenues for broader applications encompassing commercial wastewater treatment procedures.

FABRICATION OF POLYETHERSULFONE – POLYITACONIC ACID (PES-PIA) MEMBRANE FOR REMOVAL OF REACTIVE RED 120

The hazardous and mutagenic properties of dye effluents discharged into water bodies have led to the development of membrane separation for water treatment. pH-sensitive membranes have been widely employed as they exhibit remarkable improvements in the permeability and separation performance of polyethersulfone (PES) membranes. In this study, the PES membranes incorporated with polyvinylpyrrolidone (PVP), pluronic F108, and polyitaconic acid (PIA) by phase inversion were fabricated and characterized. PIA at different weight percentages were introduced into the PES dope solution via blending technique. The dye removal capacity, chemical composition, and thermal stability were characterized using UV-Vis spectrometer, fourier transform infrared (FTIR), and thermogravimetric analyzer (TGA) respectively. The fabricated membranes showed excellent rejection of reactive red 120 (RR120), which is an anionic dye. The study evaluated the membrane performance of pure water permeation (PWP) along with RR120 dye rejection. M20-PPI1, with a weight percentage of PVP/Pluronic F108/PIA; 3%/1.5%/0.25%, exhibited the highest water flux of 12 L/m2h and dye rejection of 82% at pH value of 2 for RR120 dye rejection. The findings propose that M20-PPI1 is an effective pH-sensitive membrane for dye rejection.

Solar-Induced Photocatalytic Degradation of Reactive Red and Turquoise Dyes Using a Titanium Oxide/Xanthan Gum Composite

The present study explores the solar-induced photocatalytic degradation of reactive red (RR) and reactive turquoise (RT) dyes in a single system using TiO2 immobilized in xanthan gum (TiO2/XG), synthesized using the sol–gel dip-coating technique for direct precipitation. SEM-EDX, XRD, FTIR, and UV–Vis were used to assess the characteristics of the resulting catalyst. Moreover, the effects of different operating parameters, specifically pH, dye concentration, TiO2/XG concentration, H2O2 concentration, and contact time, were also investigated in a batch photocatalytic reactor. The immobilized TiO2/XG catalyst showed a slight adsorption degradation efficiency and then improved the RR and RT dye degradation activity (92.5 and 90.8% in 120 min) under solar light with a remarkable Langmuir–Hinshelwood pseudo-first-order degradation rate of 0.0183 and 0.0151 min−1, respectively, under optimum conditions of pH 5, dye concentration of 25 mg/L, TiO2/XG concentration of 25 mg/L, H2O2 concentration of 400 mg/L, and reaction time of 120 min. The improved photocatalytic ability was ascribed to the impact of TiO2/XG nanoparticles with a high surface area, and lower band gap energy. Solar light energy has significant potential for addressing energy deficit and water pollution concerns.

Effect of Low Temperature Reactive Dye Reactive Red 2 on Dyeing and Tensile Properties of Twisted Bamboo Fibers.

This study employed bamboo as the raw material and employed the sodium chlorite method to remove most of the chromogenic groups in bamboo. The low-temperature reactive dyes were then utilized as the dyeing agents in combination with the one-bath method to dye the decolorized bamboo bundles. The dyed bamboo bundles were subsequently twisted into bamboo fiber bundles with high flexibility. The effects of various factors, including dye concentration, dyeing promoter concentration, and fixing agent concentration, on the dyeing properties, mechanical properties, and other properties of the twisted bamboo bundles were investigated using a tensile test, dyeing rate test, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. The results indicate that the macroscopic bamboo fibers prepared by the top-down method have excellent dyeability. The dyeing treatment not only improves the aesthetics of bamboo fibers but also improves their mechanical properties to a certain extent. When the concentration of dye is 1.0% (o.w.f.), the concentration of dye promoter is 30 g/L, and the concentration of color fixing agent is 10 g/L, the comprehensive mechanical properties of the dyed bamboo fiber bundles are the best. At this time, the tensile strength is 95.1 MPa, 2.45 times that of undyed bamboo fiber bundles. XPS analysis results show that the relative content of C-O-C in the fiber is significantly increased compared with that before dyeing, which indicates that the formed dye fiber covalent bond can strengthen the cross-linking between fibers, thus improving its tensile performance. The covalent bond is stable, and the dyed fiber bundle can retain its mechanical strength even after high temperature soaping.

Graphite oxide as an electronic conductor modified ZIF-8/NH2-MIL-125(Ti) hybrid material used as a photocatalyst for removal of organic dyes under visible light irradiation.

It is a great challenge to develop photocatalysts for the degradation of organic pollutants in the aqueous environment, especially those with excellent catalytic performance under visible light conditions. In this work, using graphene oxide (GO) as an electron shuttle agent and carrier, a hybrid of ZIF-8/NH2-MIL-125(Ti) and GO (ZIF-8/NH2-MIL-125(Ti)/GO) was prepared by a simple two-step solvothermal method. The morphology, structure, and combination of the synthesized catalysts were studied. The results showed that graphene oxide and ZIF-8 formed an in situ load on NH2-MIL-125(Ti). The construction of hybrid materials significantly improved the catalytic activity of NH2-MIL-125(Ti) in the visible light range. The degradation activity of the synthesized catalyst was further tested with reactive red dye. The results showed that the catalyst exhibited excellent catalytic removal efficiency for active red, with a degradation rate of 99.8% within 2 h. The prepared hybrid materials have good application prospects in the field of organic pollutant treatment in water.

PHOTOCATALYTIC DEGRADATION OF REACTIVE RED DYE AND OPTIMIZATION OF THEIR EXPERIMENTAL FACTORS

Box-Behnken design of experiment for the optimization of the experimental parameters of the photocatalytic degradation of reactive red dye using dye concentration (mg/L), catalyst dosage (mg/L), pH and time of exposure as experimental factors was studied and reported. Stock solution of reactive red dye was prepared (0.00001M) and serial dilution was used to prepare twenty-seven (27) different concentration of the dye solution which were subjected to photocatalytic degradation in a photo reactor using a ultraviolent light source under ambient environmental condition. The absorbances of these solutions before and after photo degradation was taken to obtain different percentage degradation for each experimental run. Analysis of these results was carried out using minitab 17 computer software. The result reveals the optimized conditions for the photodegredationas 10mg/L (dye concentration), 1mg/l (catalyst dosage), 5.85 pH and 90 minutes (time of exposure). This was confirmed experimentally after the optimization to prove that minitab17 software is highly effective for the optimization.

Decolorisation of Reactive Congo Red Dye Solution by Electro Coagulation Process

The decolourisation of the reactive Congo red dye from synthetic wastewater was studied using ElectroCoagulation (EC) technique. In an effort to increase removal efficiency, the effects of operating parameters including flow, inter electrode distance, conductivity, voltage, and Hydraulic Detention Time (HDT) were investigated. An electrochemical cell was initially created with an aluminum cathode and anode. Following that, each variable's impact was examined independently using synthetic wastewater. The colour removal efficiency was 93% when the initial dye concentration was 4 mg/L, the conductivity was 300 ppm, the temperature was 24 oC, the interelectrode spacing was 1 cm, and the HDT of the electrolysis was 120 min.

Bactericidal and biocatalytic temperature responsive microgel based self-cleaning membranes for water purification

The present study focuses on creating an antimicrobial and biocatalytic smart gating membrane by synthesizing unique core–shell microgels. The core–shell microgels are synthesized by grafting short chains of poly(ethylenimine) (PEI) onto a poly((N-isopropyl acrylamide)–co-glycidyl methacrylate)) (P(NIPAm-co-GMA)) core. Subsequently, the produced microgels are utilized as a substrate for synthesizing and stabilizing silver nanoparticles (Ag NPs) through an in-situ approach. These Ag NPs immobilized microgels are then suction filtered over a polyethylene terephthalate (PET) track-etched support to create cross-linked composite microgel membranes (CMMs). After structural and permeation characterization of the prepared CMMs, the laccase enzyme is then covalently grafted to the surface of the membrane and tested for its effectiveness in degrading Reactive red-120 dye. The laccase immobilized biocatalytic CMMs show effective degradation of the Reactive red-120 by 71%, 48%, and 34% at pH 3, 4, and 5, respectively. Furthermore, the immobilized laccase enzyme showed better activity and stability in terms of thermal, pH, and storage compared to the free laccase, leading to increased reusability. The unique combination of Ag NPs and laccase on a thermoresponsive microgel support resulted in a responsive self-cleaning membrane with excellent antimicrobial and dye degradation capabilities for environmentally friendly separation technology.

Adsorption of Reactive Red 120 Dye by Polyamide Nylon 6 Microplastics: Isotherm, Kinetic, and Thermodynamic Analysis

In this work, we investigated the effect of various adsorption parameters (solution pH, temperature, contact time, and the presence of phosphate and nitrate ions) on the adsorption of Reactive Red 120 (RR120) dye by Polyamide Nylon 6 (PN6) microplastics (MPs). Maximum uptake was achieved at pH 2.0, and the temperature rise from 295 to 313 K resulted in the decrease of the RR120 sorption by PN6. Equilibrium was achieved after 7 h, and the adsorption kinetic data obeyed the pseudo-second-order kinetic model. The experimental adsorption data were better fitted by the Langmuir isotherm model, and the qm was found to be 3.96 mg/g at pH 2.0 and 295 K. Thermodynamic studies pointed out that the adsorption was spontaneous and exothermic, with decreasing entropy at the solution/solid interface. Future work will focus on the effect of aging on the adsorptive properties of PN6 toward RR120 dye.

Spirulina carbon dots: a promising biomaterial for photocatalytic textile industry Reactive Red M8B dye degradation.

The colorful reactive dyes are toxic, carcinogenic to living organisms and pollute the water environment. We, for the first time, have studied the lab-scale synthesis of novel and eco-friendly carbon quantum dots (CQDs) from Spirulina platensis by microwave-assisted technology. Fluorescence, absorbance, emission, and excitation spectra of biosynthesized CQDs were recorded by UV transilluminator, UV, and photoluminescence spectrophotometer. Elemental analysis of CQDs were carried out by using energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Morphological properties of CQDs were studied by using transmission electron microscope (TEM), scanning electron microscope (SEM), and particle size analyzer. Up to 95.5% of Reactive Red M8B was degraded by CQDs within 6h under sunlight. Dye degradation was facilitated by optimized parameters such as concentration of dyes, catalyst, and pH. Photocatalytic activity of CQDs were studied by gas chromatography mass spectrometry (GC/MS). It proved that the complex molecules were degraded to simpler and easily degradable molecules. Dye degradation reaction follows first-order kinetics, and the synthesized CQDs contain 89% of scavenging activity. MTT assay proved that the treated water was toxic free and charcoal was used to remove the CQDs from treated water in order to standardize the permitted level of physico-chemical parameters such as biological oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), and total inorganic carbon (TIC); chemical, metal, and toxic-free dye treated water was suitable to recycle for algae cultivation.

Ultrasound-Assisted Synthesis of a ZnO/BiVO4 S-Scheme Heterojunction Photocatalyst for Degradation of the Reactive Red 141 Dye and Oxytetracycline Antibiotic.

The preparation of novel sunlight active photocatalysts for complete removal of pollutants from aqueous solutions is a vital research topic in environmental protection. The present work reports the synthesis of a ZnO/BiVO4 S-scheme heterojunction photocatalyst for degradation of the reactive red dye and oxytetracycline antibiotic in wastewater. ZnO and BiVO4 were first fabricated by a hydrothermal technique, and then, the ZnO/BiVO4 heterostructure was synthesized using an ultrasonic route. An increase of the surface area, compared to that of ZnO, was found in ZnO/BiVO4. The enhancement of charge separation efficiency at the interface was obtained so that a remarkable enhancement of the photocatalytic performance was detected in the prepared heterojunction photocatalyst. Complete detoxification of harmful pollutants was achieved by using the economical solar energy. The removal of the pollutants follows the first-order reaction with the highest rate constant of 0.107 min-1. The stability of the prepared photocatalyst was detected after five cycles of use. The ZnO/BiVO4 S-scheme heterostructure photocatalyst still provides high photoactivity even after five times of use. Hydroxyl radicals play an important role in the removal of the pollutant. This work demonstrates a new route to create the step-scheme heterojunction with high photoactivity for complete removal of the toxic dye and antibiotic in the environment.

COMPUTER SOFTWARE AIDED PHOTOCATALYTIC DEGRADATION OF VAT YELLOW DYE USED IN LEATHER AND TEXTILE INDUSTRIES

This research investigated design of experiment for the optimization of the experimental parameters of the photocatalytic degradation of VAT yellow dye using dye concentration (mg/L), catalyst dosage (mg/L), pH and time of exposure (minates) as experimental factors. Stock solution of vat yellow dye was prepared (0.00001M) and serial dilution was used to prepare twenty seven (27) different concentrations of the dye solution which were subjected to photocatalytic degradation in a photo reactor using a ultraviolent light source under ambient environmental condition. The absorbances of these solutions before and after photo degradation were taken to obtain different percentage degradation for each experimental run. Analysis of these results was carried out using minitab18 computer software. The result revealed the best conditions for the photodegredation as (20mg/l) (dye concentration), 2(mg/L) (catalyst dosage), 3.39 pH and 45 minutes (time of exposure). This was confirmed experimentally after the optimization to prove that minitab18 software is highly effective for the optimization of photodegradation of tannery and textile effluent containing reactive red dye.

Ag-Modified ZnO for Degradation of Oxytetracycline Antibiotic and Reactive Red Azo Dye.

It is known that low electron-hole separation efficiency is the major disadvantage influencing low photoactivity of the UV-active ZnO photocatalyst. To solve this drawback, the excellent fabrication technique has been used to disperse silver metal on ZnO surface. In this study, an addition of silver content up to 15 wt% was carried out. The 5Ag-ZnO sample, comprising 5 wt% of silver metal, displayed a hexagonal wurtzite structure, and a band gap of 3.00 eV, with high sunlight-active photocatalytic performance of 99-100% and low photo-corrosion problem. The complete degradation of oxytetracycline (OTC) antibiotic and reactive red dye 141 (RR141) dye under natural sunlight was achieved. The highest rate constant of 0.061 min-1 was detected. The enhancement of the performance is mainly due to lowering of the electron-hole recombination rate. Dispersion of silver on ZnO causes the generation of the Schottky barrier at the interface between Ag and ZnO, so that improvement of quantum efficiency and enhancement of the resultant photoactivity could be expected. Furthermore, good distribution of metallic silver also causes a red shift in absorption of light toward the visible spectrum. This is strongly attributed to the surface plasmon resonance effect, which occurred after successful decoration of the noble metal on ZnO. The photocatalyst, with great structural stability, still maintains high photocatalytic efficiency even after five times of use, implying its excellent cycling ability. The present finding offers a new road to generate a silver decorated ZnO photocatalyst for the complete removal of dye and antibiotics contaminated in the environment.

Effective Removal of Reactive and Direct Dyes from Colored Wastewater Using Low-Cost Novel Bentonite Nanocomposites

The present study was aimed to remove direct violet-51, reactive green-5, reactive red, and acid red dyes by novel bentonite clay nanocomposites prepared using sodium metasilicate and potassium ferricyanide. The effect of temperature, pH, adsorbent amount, contact time, and initial concentration were studied to optimize the removal process. Various adsorption isotherms (Temkin, Freundlich isotherm, Langmuir isotherm, Harkin Jura, and Dubinin Radushkevich models) and kinetic models (pseudo-first order and pseudo-second order) were applied to adsorption data to find out the best fit model, i.e., Freundlich isotherm and pseudo-second order model. The prepared samples of bentonite nanocomposites were characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Bentonite treated with sodium metasilicate and potassium ferricyanide removed 96.6% of direct violet-51 dye, bentonite treated with sodium metasilicate removed 95%, bentonite treated with potassium ferricyanide removed 94%, and pure bentonite removed 80% of the dye from the solution.

Innovation and application of dyes with high fixation

Reactive dyes are the main species for cotton dyeing due to their wide range of hue, satisfactory color fastness and facile application method. Aiming at increasing fixation on cotton fibers, benzimidazolone yellow reactive dyes, sulfonamide red reactive dyes and anthraquinone azo blue reactive dyes are designed. The preparation, characterization and application properties of these dyes with high fixation are introduced in detail. In order to achieve dye fixation to near 100%, macromolecular crosslinking reactive dyes are designed, their dyeing and fixing mechanism are discussed. These novel reactive dyes show promising application prospect in dyeing and printing of cotton fibers.

Application of Salvinia sps. in remediation of reactive mixed azo dyes and Cr (VI) - Its pathway elucidation

The emerging industrialization has resulted in the rapid growth of textile industries across the globe. The presence of xenobiotic pollutants in textile wastewater threatens the ecosystem. Applying different microbes (bacteria, fungi & algae) has paved the way for phytoremediation – the eco-friendly, cost-effective method. The present study focuses on the phytoremediation of reactive dyes - Reactive red, Reactive Brown & Reactive Black and Cr (VI) in synthetic textile wastewater using Salvinia sps. The mixed azo dyes of each 100 mg/L showed decolourization of 75 ± 0.5% and 82 ± 0.5% of removal of 20 mg/L of Cr (VI) after eight days of incubation in a phytoreactor setup. Chlorophyll analysis revealed the gradual decrease in the photosynthetic pigments during the remediation. The degraded metabolites were analyzed using FT-IR and showed the presence of aromatic amines on day zero, which were converted to aliphatic amines on day four. The GC-MS analysis revealed the disruption of –NN- bond, rupture of –CN- bond, scission of –N-N-bond, and loss of –SO3H from the Reactive Black dye leading to the formation of an intermediate p-Hydroxy phenylhydrazinyl. The rupture of Reactive red dye resulted in the formation of p-Hydrazinyl toluene sulphonic acid, Naphthyl amine −3,6-disulphonic acid and 8-Hydroxy Naphthyl amine −3,6-disulphonic acid. Decarboxylation, desulphonation, deoxygenation and deamination of Reactive Brown dye showed the presence of different metabolites and metabolic pathways were proposed for the reactive azo dyes which were phytoremediated.

Statistical Analysis and Optimization of the Brilliant Red HE-3B Dye Biosorption onto a Biosorbent Based on Residual Biomass.

Using various techniques, natural polymers can be successfully used as a matrix to immobilize a residual microbial biomass in a form that is easy to handle, namely biosorbents, and which is capable of retaining chemical species from polluted aqueous media. The biosorption process of reactive Brilliant Red HE-3B dye on a new type of biosorbent, based on a residual microbial biomass of Saccharomyces pastorianus immobilized in sodium alginate, was studied using mathematical modeling of experimental data obtained under certain conditions. Different methods, such as computer-assisted statistical analysis, were applied, considering all independent and dependent variables involved in the reactive dye biosorption process. The optimal values achieved were compared, and the experimental data supported the possibility of using the immobilized residual biomass as a biosorbent for the studied reference dye. The results were sufficient to perform dye removals higher than 70–85% in an aqueous solution containing around 45–50 mg/L of reactive dye, and working with more than 20–22 g/L of prepared immobilized microbial biosorbent for more than 9.5–10 h. Furthermore, the proposed models agreed with the experimental data and permitted the prediction of the dye biosorption behavior in the experimental variation field of each independent variable.

Sulfate Decelerated Ferrous Ion-Activated Persulfate Oxidation of Azo Dye Reactive Brilliant Red: Influence Factors, Mechanisms, and Control Methods

This study investigated the inhibition effects of sulfate on ferrous ion-activated persulfate oxidation of azo dye reactive brilliant red X-3B. The experimental results showed that the degradation efficiency of reactive brilliant red X-3B decreased from 100% to 63% in 60 min when the initial concentration of sulfate increased from 0 to 3 g/L. The ferrous/persulfate molar ratio had remarkable influence on persulfate oxidation capability in presence of sulfate. SO42− could coordinate with Fe2+ and Fe3+ in generating FeSO4 ion pairs as well as FeSO4+ or Fe(SO4)2− complexes, which were difficult to activate persulfate and reduced the regeneration of Fe2+. Radicals quenching and electron paramagnetic resonance experiments showed that ·OH and SO4·− were responsible for the oxidation of reactive brilliant red X-3B; however, the addition of sulfate significantly inhibited the generation of SO4·−, and then the generation of ·OH. Moreover, the corresponding Nernst equation indicated that high concentration of sulfate reduced the oxidation potential of SO4·−/SO42−. Experimental results proved that the adverse effects of sulfate on the persulfate oxidation could be counteracted either by batch addition of ferrous or by adding Ba2+ to remove SO42− in the system.

Synthesis of ZnO Nanorods-Based Photoanode and Electrochemical Characterization for Azoic Dyes Degradation: Reactive Red 239 Study Case

The use of solar energy as an energy vector has been a subject of great interest and study in recent years, showing vast improvements in the efficiencies associated with the conversion to electrical energy. This interest has extended to various applications, among which the production of green hydrogen from the decomposition of water and in environmental remediation processes stand out.The main motivation in focusing the use of solar energy in photoelectrocatalytic degradation processes is the negative impact that the disposal of colored water has on the different effluents, causing a deterioration of the quality of these ecosystems and the death of many forms of life. In this sense, the application of semiconductors based on zinc oxide (ZnO) supported on FTO conductive glass was studied for the treatment of wastewater from the textile industry, contaminated with reactive red azo dye 239.The main motivation in focusing the use of solar energy in photoelectrocatalytic degradation processes is the negative impact that the disposal of colored water effluents has on the different ecosystems, causing a deterioration of the quality of these ecosystems and the death of many forms of life. In this sense, the application of semiconductors based on zinc oxide (ZnO) supported on FTO was studied for the treatment of wastewater from the textile industry, contaminated with reactive red azo dye 239.In the present writing, a process for the synthesis of a ZnO-based semiconductor was defined. This precedence was performed directly on the substrate of 15x15x1.1mm FTO conductive glass plates. Prior to the synthesis process, a pretreatment of the glass is performed. The pretreatment of the plates consists of washing with neutral soap, then immersion in 0.01 M nitric acid (HNO3) for 10 minutes, and finally, cleaning with deionized water in ultrasound for 10 minutes. The synthesis of the nanostructured ZnO was performed in two steps. First, a chronoamperometric electrodeposition of the ZnO seeds on the substrate at a fixed potential of -1.38 V vs. Ag/AgCl as reference, and a platinum electrode as counter electrode, was performed at 70ºC for 200 seconds with a Gamry® Interface 1000 potentiostat, then subjected to a heating period at 400ºC for 2 hours. After electronucleation of the seeds and heat treatment, an additional step is carried out, which is the chemical growth of ZnO, waiting for the formation of ZnO nanorods in the (100), (002) and (101) planes typical of the wurtzite structure, this is done in a zinc nitrate solution at 90ºC, pH > 13.5, for 75 minutes.In the semiconductor characterization, different electrochemical techniques such as cyclic voltammetry, electrochemical impedance spectroscopy and anodic linear scanning were evaluated. At the same time, the response of the photoanode to illumination with a 350 W xenon arc lamp was studied, showing the remarkable effect of light on the generation of charge carriers, decreasing recombination, and increasing photocurrents. On the other hand, the density of charge carriers in the semiconductor was evaluated and defined, as well as the position of the valence and conduction bands and their respective band gap.The charge carrier density was determined from Mott-Schottky, finding densities of 6.25x1021 and 3.72x1021 carriers/cm3, for frequencies of 500 and 1000 Hz, respectively. In parallel, the flat band potential, which under certain circumstances of charge carrier density can approximate the conduction band potential, was evaluated. This was estimated from three methods, Mott-Schottky (500 and 1000 Hz), photocurrent onset potential and open circuit potential, finding values of -0.086 and -0.124 (at 500 and 1000 Hz), -0.121 and -0.161 V vs. Ag/AgCl, respectively. The determination of the bad gap was performed from UV-VIS, obtaining a value of 3.13 eV.Finally, the discoloration of the solution was evaluated from UV-VIS measurements. This analysis was performed on a problem solution that resembles the concentration of dye and salts of a textile industry effluent. A ZnO electrode was used, with a defined working area of 1.30 cm2, and a dye volume of 25 mL. The experiment was carried out for a time period of 4 hours, and an applied potential of 1 V vs. Ag/AgCl/Cl- 3M, reaching a decolorization of 23.2% of the initial solution.