Degradation Of Dye Wastewater Research Articles

Preparation of Heterogeneous Fenton Catalysts Cu-Doped MnO2 for Enhanced Degradation of Dyes in Wastewater.

Herein, a series of heterogeneous Fenton catalysts, Cu doped MnO2 (CDM), with different Cu/Mn molar ratios were prepared via a hydrothermal reaction. Meanwhile, detailed characterizations were used to study the structures of CDM, and it is amazing that the morphology of CDM changed from nanowires to nanoflowers with an increasing amount of Cu doped. Apart from this, both the specific surface area and oxygen vacancy increased obviously with the increasing Cu/Mn molar ratio. Then, the degradation of different dyes was utilized to evaluate the catalytic activity of different CDM with H2O2 used as the oxidizing agent, and the 50%-CDM with the highest content of Cu doped displayed the best catalytic activity. Herein, the degradation efficiency (D%) of Congo red (CR) solution with low concentration (60 mg/L) reached 100% in 3 min, while the D% of CR solution with a high concentration (300 mg/L) reached 99.4% after 5 min with a higher dosage of H2O2. Additionally, the 50%-CDM also displayed excellent reusability, for which the D% values were still higher than 90% after the 14th cycles. Based on the structure characteristics and mechanism analysis, the excellent catalytic capacity of 50%-CDM was due to the combined influence of large specific surface area and abundant oxygen vacancy. Thus, a promising heterogeneous Fenton catalyst was developed in this study, which proved the treatment efficiency of actual dye wastewater.

Exploring the influence of lanthanum doping on pyroelectric and pyrocatalytic Characteristics in NBT-BT-2Zn ceramics

The present work investigates the pyroelectric properties of 0.94Na1/2Bi1/2TiO3-0.06BaTiO3-0.02Zn-xLa (NBT-6BT-2Zn-xLa; x = 0, 0.25, 0.5 and 1 in mole %) and its use in methylene blue (MB) dye degradation in wastewater. La doping is used to enhance the pyroelectric properties of NBT-6BT-2Zn for energy harvesting and pyrocatalysis applications. The 0.25 mol % La-doped sample consists of a maximum pyroelectric coefficient of 3.8 × 10−4 C m−2 °C−1 and shows a 55% MB dye decomposition. The presence of •OHandO2•− is confirmed by scavengers and radical trapping experiments. The repeatability test ensures the reusability of the NBT-6BT-2Zn-0.25La as a pyrocatalyst for dye degradation. The bulk form of NBT-6BT-2Zn-0.25La is also investigated to overcome the limitations of powder recovery in dye degradation.

Natural sunlight energy harvesting using NiAl2O4@N-rGO hetero-junction for photocatalytic degradation of crystal violet dye: Kinetic and mechanistic insights

In this study, NiAl2O4 (NA) was synthesized by the co-precipitation route and its hetero-junctions were fabricated with N-doped reduced graphene oxide (N-rGO) through the ultra-sonication method. The structural, morphological, magnetic, optical and photocatalytic properties of synthesized NA, N-rGO, and the NA@N-rGO 1–4 hetero-junctions characterized by XRD, FTIR, SEM, VSM, PL and UV–visible spectroscopy, respectively. XRD results showed that crystallite size decreases from 25.01 nm (NA) to 15.20 nm for NA@N-rGO-4 and porosity increases up to 77.7 % for NA@N-rGO-4 making it remarkable for photocatalytic applications and FTIR results confirmed the formation of N-rGO as well as its successful integration into NA matrix, resulting in the formation of hetero-junctions. Magnetic properties were investigated using a vibrating sample magnetometer (VSM), revealing distinctive S-shaped hysteresis loops at 25 °C for both NA and N-rGO, as well as the NA@N-rGO 1–4 hetero-junctions and magnetic saturation decreases with an increase in N-rGO content as for NA@N-rGO-4 Ms drops to 0.0038 emu/g. Notably, the bandgap of NA@N-rGO-4 hetero-junction was effectively reduced from 3.0 eV (in the case of NA) to 2.1 eV, resulting in a discernible decrease in photoluminescence (PL) intensity and increase in e--h+ pair separation. Under visible light, NA@N-rGO-4 exhibited a remarkable 94.68 % efficiency in crystal violet (CV) dye degradation within just 90 min, outperforming NA's 59.05 % degradation efficiency and OH. Radicals play a major contribution to the degradation of dye. The optimization of degradation capabilities was achieved through the manipulation of catalyst dosage, dye concentration and varying pH values for the degradation of CV dye. NA@N-rGO-4 hetero-junction demonstrates the considerable potential for efficient dye degradation in wastewater under visible light, owing to its exceptional catalytic performance.

Bifunctional boron-nitrogen-containing graphite felt cathode for highly efficient treatment on dye wastewater depending on the metal-free electro-Fenton process

The heterogeneous electro-Fenton technology can settle a matter of narrow pH application range in the traditional electro-Fenton process. Direct O2 electro-reduction to •OH on the surface of metal-free catalysts can effectively solve the problem of easy leaching of metal-based catalysts under acidic conditions and improve the oxidation efficiency of H2O2. In this work, a stable bifunctional boron-nitrogen-containing catalyst was directly synthesized on the surface of graphite felt. The H2O2 yield (4.32 mg cm-2 h−1) and rhodamine B degradation rate (0.174 min−1) of boron-nitrogen-containing catalyst were significantly improved at the pH value of 7, compared with nitrogen-containing graphite felt catalyst. The catalyst had a rapid degradation ability for various dyes and actual dye wastewater, and the specific energy consumption of actual dye wastewater degradation was 4.02 kW h kg−1 COD-1 lower than that reported in literature (6.38–29.7 kW h kg−1 COD-1). DFT calculations and XPS results revealed the potential reaction mechanism. The introduction of −BCO2 group into the nitrogen-containing plane significantly enhanced the oxygen adsorption and oxygen reduction activity, and the directly formation of •OH was promoted jointly by graphite nitrogen and −BCO2 group. This work provided a new insight into the development of metal-free electro-Fenton catalyst.

Potential of White Rot Fungi from Berbak-Sembilang National Park, Indonesia for Decolorization and Detoxification Commercial Direct Dyes

Commercial direct dyes are frequently employed in the dyeing of Jumputan, a traditional craft originating from South Sumatra, Indonesia. The introduction of synthetic dyes into the environment can have a detrimental impact on ecosystem stability, necessitating the implementation of remedial measures. There has been a growing interest in the utilization of White Rot Fungi (WRF) as a viable biological agent for the purpose of decolorizing and detoxifying synthetic colors. However, it is imperative to investigate the isolated WRF from Berbak-Sembilang National Park (TNBS) due to the varying capacities of decolorization and detoxification exhibited by each WRF. The study involved 5 WRF from TNBS screened in solid media, and grown in a liquid medium containing commercial direct dyes (direct turquoise, direct orange and direct yellow). WRF grown on liquid medium contains a single dye, mixture dyes and temperature characterization. It measured decolorization, biomass and enzyme activities. Toxicity is measured by the BSLT method. The findings indicated that 3 specific fungi, namely Phellinus noxius (BRB 11), Lentinus sajor-caju (BRB 12) and Leotrametes menziesii (BRB 73), exhibited a significant capacity to remove the color from both individual and mixture of direct dyes through the production of laccase and MnP enzymes. The optimal temperature for decolorization of the mixture of direct dyes was 35 °C for BRB 11 (61.4 %) and BRB 73 (60.7 %), whereas BRB 12 (47.4 %) exhibited optimal temperature at 30 °C. The toxicity assay conducted using A. salina showed a progressive rise in the LC50 value, from 15.37 mgL−1 in the control group to a range of 21.63 - 35.84 mgL−1 in the treated group, indicating a detoxification process. However, the most toxic isolate was BRB 12. This study proposes the potential of 2 isolates, Phellinus noxius (BRB 11) and Leotrametes menziesii BRB 73, from TNBS for degradation of single and mixture dye wastewater in the environment. HIGHLIGHTS The discovery of 3 White Rot Fungi from TNBS (Indonesia) has the ability to remove color and reduce the level of toxicity of commercial direct dyes, both individual and mixture of commercial direct dyes. Uncovering one of White Rot Fungi has not been widely published for decolorization and detoxification commercial direct dyes, namely Leotrametes menziesii (BRB 73). The optimal temperature was 35 °C for decolorization of commercial direct dyes by Phellinus noxius (BRB 11) and Leotrametes menziesii (BRB 73) GRAPHICAL ABSTRACT

A water stable Cu-MOF/GO composite as a persulfate activator for efficient degradation of dye wastewater

Water pollution caused by textile dyes is considered a major and growing issue. To address this challenge, in this research, water-stable Cu-MOFs/GO composite catalysts were produced using the hydrothermal synthesis method as an efficient persulfate (PDS) activator for methyl orange (MO) degradation. We also explored the changes in surface morphology, crystal structure, surface functional groups, and valence states of the materials before and after the introduction of GO by Cu-MOFs. It was shown that Cu-MOFs/GO demonstrates a more stable surface structure, and the unique folded structure of GO provides a better hydrophobic environment for Cu metal cluster hence making MOF easier to grow. The Cu-MOFs/GO-PDS system showed a high activation performance on persulfate in a wide pH range (3–11), meanwhile, was less affected by the presence of natural anions in the environment and more inhibited by natural organic matter citric acid. Furthermore, the Cu-MOFs/GO had excellent stability, reusability and structural integrity, and the removal rate of MO was maintained after five cycles. In terms of oxidation mechanism, in addition to the generation of ·SO4− and OH· radicals, there were also singlet oxygen 1O2 and active Cu(III) in the system, and all of these active substances contributed to the removal of pollutant MO.

Comparison of treatment performance and microbial community evolution of typical dye wastewater by different combined processes

The degradation of typical dye wastewater is a focus of research in the printing and dyeing industry. In this study, a combined micro-electrolysis and microbial treatment method was established to treat refractory dye wastewater, and the pivotal factors in the microbial treatment were optimized. In the series and coupled modes, the removal rates of chroma reached 98.75% and 92.50%, and the removal rates of chemical oxygen demand (COD) reached 96.17% and 82.29%, respectively. The high-throughput sequencing results showed that the microbial communities in the microbial system varied at different treatment stages. From the culture stage to the domestication stage, the dominant phylum was Proteobacteria; however, the community abundance of microorganisms decreased. A combination of micro-electrolysis and biological methods can alter the characteristics of the microbial community, increase the number of dominant phyla, and increase the abundance of microorganisms. The degradation effect of the series mode and the overall strengthening effect of micro-electrolysis on the microorganisms were better than those of the coupled mode. In actual wastewater, the maximum removal rates of chroma, COD, total nitrogen (TN), ammonia nitrogen (NH3-N), and total phosphorus (TP) are 97.50%, 98.90%, 94.35%, 93.95%, and 91.17%, respectively. Three-dimensional fluorescence spectrum analysis showed that microbial processes could significantly degrade fluorescent components in wastewater, and methanogenic active enzymes in anaerobic processes could continue to react. The combined process can realize the efficient treatment of toxic dye wastewater by reducing the toxicity of wastewater and efficiently degrading organic matter, which has important guiding significance for the treatment of refractory dye wastewater.

Pulsed laser-indued nanoscale phase transition in FePC alloy with enhancing the catalytic activity in dye wastewater degradation

A nanoscale heterogeneous environmental catalyst, FePC alloy, was successfully fabricated by a single-roller melt spinning technique. The prepared catalyst had a biphasic disorder structure with α-Fe nanocrystallites embedded in the amorphous matrix. The pulsed laser process effectively improved the nanoscale heterogeneity degree, thermodynamic properties, surface photothermal conversion, corrosion resistance and hydrophilicity of the catalyst. The 60 W pulsed laser processing induced the nanocrystalline Fe3P precipation in the catalyst, which is transformed from α-Fe and amorphous matrix, promoting the electron donation rate of the galvanic cell system; therefore, the 60 W pulsed laser processed catalyst exhibited an excellent catalytic performance, such as a high k value, strong TOC removal rate and low activation energy. In addition, compared with other oxide, metallic crystal and metallic glass catalysts, this catalyst exhibited a much higher surface area-normalized rate constant kSA. The reusability test showed that this catalyst exhibited a reliable stability, and its decolorization efficiency at the 20th cycle still remained above 95 %; moreover, the parameter analysis showed that it had a strong adaptability in the persulfate system. This study provides a new strategy for designing and fabricating the efficient, low-cost and environmental catalysts for dye wastewater degradation.

Effect of pH on the photo-Fenton degradation of rhodamine B by Prussian blue/g-C<sub>3</sub>N<sub>4</sub>

The pH solution is one of the critical factors affecting the photo-Fenton degradation of dyes in wastewater. The photoactivity of Prussian blue/g-C3N4 was investigated using the photodegradation of RhB acidic, neutral, and essential medium. The results implicated that more than 98.5% removal of RhB was achieved at pH = 3.62 after irradiation for 60 minutes under visible light. The photocatalytic activity of Prussian blue/g-C3N4 showed the best performance in an acidic medium. This is due to the formation of hydroxyl radicals during the photocatalytic degradation of RhB. Thus, this study has shown the role and potential of the application of photocatalysts in the degradation of toxic organic compounds the wastewater.

ZnO/ZIF-8 nanocomposite for orange G dye degradation: synthesis, characterization, photocatalytic activity, and mechanism

Textile dyes are one of the dominant reasons for water pollution. Among these dyes, Orange G is toxic, carcinogenic, and non-biodegradable and can cause a severe threat to humans and marine life. Therefore, in this present work, a novel photocatalyst was synthesized, and systematic degradation of Orange G dye was investigated. The novel ZnO/ZIF-8 nanocomposite has been successfully synthesized via a two-step method, thermal decomposition for ZnO and wet-chemical method for ZnO/ZIF-8 nanocomposite. The band gap of the nanocomposite was calculated using a KM plot and found to be 3.5 eV. The surface charge of the materials was examined using zeta potential measurement, which was found to be suitable for dye degradation. The recombination time of the materials was investigated using Time-Resolved Photoluminescence (TRPL) study, and it was found that nanocomposite has a lower recombination rate than pristine materials. The degradation efficiency of materials towards Orange G dye was calculated to be ∼95% after 120 min illumination. The photocatalysis mechanism was proposed on the basis of Mott–Schottky measurements, which were supported by the scavenger test. Furthermore, to evaluate the reusability of the nanocomposite, a photocatalytic experiment was conducted several times. The ZnO/ZIF-8 nanocomposite could be used for the degradation of textile dye wastewater.

Discerning the catalytic treatment of cationic dye wastewater in photoreactor comprising ternary (Co3+/Co2+)-embedded SnO2/ZnFe2O4 composite sensitive toward ultra-violet illumination.

Herein, magnetic (Co3+/Co2+)-integrated SnO2, SnO2/ZnFe2O4, and ZnFe2O4 composites have been prepared from triply distilled water and 30% of isopropanol in the water medium. The phase evolution, microstructure, and magnetism were investigated successfully and tested for cationic dye wastewater degradation containing Rhodamine 6G and Methylene Blue under ultra-violet irradiation. Composite spheres are attributed to efficient heterojunction interfaces between ZnFe2O4 and SnO2 semiconductors with the support of (Co3+/Co2+) nanoparticles. The results provide a simple, low-cost, environmentally friendly, and scalable method of ternary composites to degrade mixed dyes. Co3+/Co2+-implanted SnO2/ZnFe2O4 offered narrowed bandgap energy, more light absorption, diminishing electron-hole recombination, and more charge carriers toward cationic dye wastewater than the binary components. The rate constant of Rhodamine 6G degradation was observed at 0.0237min-1, and Methylene Blue degradation was observed at 0.0187min-1 at 90min under UV (λ = 365nm) irradiation. Capturing studies of various organic reactive species and mechanisms of composites was also proposed in detail.

Simultaneous Efficient Photocatalytic Hydrogen Evolution and Degradation of Dye Wastewater without Cocatalysts and Sacrificial Agents Based on g-C3N5 and Hybridized Ni-MOF Derivative-CdS-DETA.

Inspired by energy conversion and waste reuse, hybridized Ni-MOF derivative-CdS-DETA/g-C3N5, a type-II heterojunction photocatalyst, is synthesized by a hydrothermal method for simultaneous and highly efficient photocatalytic degradation and hydrogen evolution in dye wastewater. Without the addition of cocatalysts and sacrificial agents, the optimal MOF-CD(2)/CN5 (i.e. Ni-MOF derivative-CdS-DETA (20 wt.%)/g-C3N5) exhibit good bifunctional catalytic activity, with a H2 evolution rate of 2974.4µmolg-1h-1 during the degradation of rhodamine B (RhB), and a removal rate of 99.97% for RhB. In the process of H2-evolution-only, triethanolamine is used as a sacrificial agent, exhibiting a high H2 evolution rate (19663.1µmolg-1h-1) in the absence of a cocatalyst, and outperforming most similar related materials (such as MOF/g-C3N5, MOF-CdS, CdS/g-C3N5). With the help of type-II heterojunction, holes are scavenged for the oxidative degradation of RhB, and electrons are used in the decomposition of water for H2 evolution during illumination. This work opens a new path for photocatalysts with dual functions of simultaneous efficient degradation and hydrogen evolution.

Facile green fabrication of copper/polyvinylidene fluoride nanocomposite for pathogens disinfection and dye degradation in wastewater

This study aimed to explore the production of valuable nanomaterials using natural waste-derived extracts through a green synthesis approach. Copper nanoparticles (CuNPs) were successfully fabricated using coffee grounds as a reducing agent. Characterization via TEM and DLS confirmed the small average size of the biogenic CuNPs, while XRD analysis indicated their formation in a pure state without impurities. To enhance effectiveness in bacterial disinfection, dye degradation, and conductivity, a CuNPs@polyvinylidene fluoride (PVDF) nanocomposite was developed. Various spectroscopic and microscopic methods validated CuNPs production. Experimental data demonstrated significant antibacterial activity in the CuNPs@PVDF nanocomposite, eliminating harmful bacteria (Salmonella enterica, Klebsiella pneumoniae, Bacillus subtilis, and Enterococcus faecalis) within 60 to 115 min. At concentrations of 50, 100, and 150 µg/mL, the nanocomposite notably accelerated Methyl Red (MR) dye degradation, achieving degradation rates of 68.72 %, 81.48 %, and 100 % after 150 min. These findings advocate for the potential use of the CuNPs@PVDF nanocomposite in eliminating pathogens and reducing organic dye pollution. Its eco-friendly synthesis, effective disinfection, and photocatalytic proficiency signify its wide applicability in water treatment, establishing it as a promising solution for tackling water contamination issues.

Enhanced photocatalytic degradation of dyes using a novel waste toner-based TiO2/Fe2O3@nanographite nanohybrid: A sustainable approach

This study synthesized a ferric oxide–nanographite (NG) nanocomposite (Fe2O3@NG) from waste toner powder through carbonization. Subsequently, a TiO2/Fe2O3@NG nanohybrid was fabricated using the sol–gel technique to improve the photocatalytic degradation of dyes. TiO2/Fe2O3@NG nanocomposites were prepared at TiO2:Fe2O3@NG ratios of 2:1 (Ti:T-21), 1:1 (Ti:T-11), and 1:2 (Ti:T-12). The porosity, morphology, surface chemistry, and chemical interactions between TiO2, Fe2O3, and graphite in the prepared TiO2/Fe2O3@NG nanocomposites were characterized using the Brunauer–Emmett–Teller (BET) method and microscopic and spectroscopic analyses. The TiO2/Fe2O3@NG nanohybrid exhibited a reduced bandgap (2.4–2.9 eV) and enhanced charge carrier separation through charge transfer at the junction of the hetero-structured TiO2/Fe2O3@NG nanohybrid. Preliminary experiments revealed that Ti:T-21 was the most effective photocatalyst for degrading acid blue-25 (AB-25) compared to Ti:T-11, Ti:T-12, sole TiO2, and Fe2O3@NG. This study also investigated the impacts of catalyst dose and initial dye concentration on the AB-25 photocatalytic degradation. Notably, 97% of 5-mg/L AB-25 was removed using 1.25-g/L Ti:T-21 at an unmodified pH of 6.4 within 120 min. Furthermore, Ti:T-21 exhibited remarkable recyclability in its immobilized form, achieving degradation ratios of 74.7%–71.8% over five consecutive runs, compared to removal efficiencies of 85.0%–62.3% in the suspended mode. Trapping experiments identified hydroxyl radicals, holes, and superoxide as the principal reactive radicals. The TiO2/Fe2O3@NG/light system was effective in disintegrating and mineralizing other synthetic dyes such as Congo red, methylene blue, and methyl red, indicating its potential for industrial-scale degradation of authentic dye wastewater. The utilization of waste toner for water treatment is highlighted as a strategy to promote environmental sustainability, foster a circular economy, and contribute to pollution remediation.

Research Progress on Photocatalytic Degradation of Methyl Orange Dye Wastewater by Light‐assisted Composite‐modified Ag3PO4

AbstractA new type of modified catalyst was prepared by a silver ammonia‐assisted precipitation method through a custom‐built electrochemical reactor, and the catalytic degradation of the azo dye methyl orange was studied under the synergistic effect of visible light. The optimum doping ratio for the loading of graphene oxide (GO) is 1.0 %. Under the optimum conditions, the degradation rate of Ag3PO4/GO/NiFe2O4 to methyl orange is 97.56 % when the light reaction time is 50 min. After three cycles, the degradation rate of methyl orange by Ag3PO4/GO/NiFe2O4 is 94.47 %. Through the free radical capture experiment, it is known that the contribution degree of the main active substances in the photocatalytic degradation of methyl orange is h + >⋅O2− >⋅OH. By forming a Z‐type heterojunction between Ag3PO4 and NiFe2O4, the recombination probability of photogenerated carriers is greatly reduced, and the stability of Ag3PO4 is improved.

Photocatalytic Degradation of Malachite Green by Titanium Dioxide/Covalent Organic Framework Composite: Characterization, Performance and Mechanism.

In this paper, a titanium dioxide/covalent organic framework (TiO2/COF) composite was prepared and its photocatalytic removal of dye was investigated. Using tetrabutyl titanate as a titanium source, TiO2 nanomaterial was prepared by sol-gel method. In the presence of TiO2, TiO2/COF core-shell composite was prepared by solvothermal synthesis using melamine and 1,4-phthalaldehyde as ligands. The prepared materials are characterized by SEM, TEM, XPS, XRD, TG, FTIR, BET, EPR, PL, and UV-Vis-DRS techniques. Using malachite green as a model of dye wastewater, the photocatalytic degradation performance of TiO2/COF composites was investigated under the irradiation of ultraviolet light. The results show that the modification of COF significantly improves the photocatalytic efficiency of TiO2, the degradation rate increases from 69.77 % to 93.64 %, and the reaction rate constant of the first-order kinetic equation is increased from 0.0078 min-1 to 0.0192 min-1. Based on the free radical capture experiment, the photocatalytic degradation mechanism of TiO2/COF was discussed, and the feasibility of its photocatalytic degradation of malachite green was theoretically clarified. Accordingly, a simple and practical method for photocatalytic degradation of malachite green was constructed, which has potential application value in the degradation of dye wastewater.

Construction of Co-doped Fe2O3/carbonized melamine foam heterogeneous catalyst for enhanced degradation of organic pollutants through peroxymonosulfate activation

Co-doped Fe2O3/carbonized melamine foam heterogeneous catalyst (CMF/Co-Fe2O3) was prepared by hydrothermal method. Rhodamine B (RhB) degradation was employed as a model test for evaluating peroxymonosulfate (PMS) activation. The degradation efficiency of RhB can reach 97 % in the catalyst dosage (50 mg/L), PMS concentration (100 mg/L), pH = 7 and RhB initial concentration (10 mg/L) after 60 min reaction. The reaction rate constant is 10 times higher than that of CMF/Fe2O3 and the activation ability of PMS is greatly improved. The degradation efficiency of RhB can be inhibited by increasing the initial mass concentration of RhB and pH value. The effect of temperature on the degradation rate of RhB conforms to the Arrhenius model, and the degradation process is a surface reaction controlled process. The results of free radical capture experiments and electron paramagnetic resonance (EPR) experiments showed that SO4¯ was the main active free radical for RhB degradation. After four cycles, the degradation efficiency of RhB still maintains 80 % with CMF/10 %Co-Fe2O3 catalyst. The heterogeneous catalyst exhibited potential application in the field of degradation of dye wastewater due to its excellent cycling stability.

Photocatalytic degradation of azo dye wastewater promoted by inorganic acid post-treated carbon nitride

A series of inorganic acid post-treated carbon nitride was synthesized to regulate the electronic structure, surface properties and then improve the photocatalytic activity.

Research Progress on Degradation of Methylene Blue Dye Wastewater by Electro-Fenton Process

Research Progress on Degradation of Methylene Blue Dye Wastewater by Electro-Fenton Process

Application of the synergistic Ti/SnO2–Sb–Cu anode and Ti/ZnO/CuO cathode in the electrochemical treatment of wastewater

The current research mostly focused on the single working electrode of anode for the treatment of wastewater. Therefore, a low-cost dual-electrode system using Ti/SnO2–Sb–Cu (TSSC) as the anode and Ti/ZnO/CuO (TZC) as the cathode was constructed for the synergistic treatment of methylene blue dye wastewater. Electrochemical analyses of the TSSC electrode show an ultra-high oxygen evolution potential of 2.2 V, the greater stability and the excellent corrosion resistance when compared with the traditional Ti/SnO2–Sb (TSS) electrodes. Hydroxyl radicals (•OH) are thought to be the main oxidants in the degradation process, the results show that the content of •OH of the TZC cathode is 57 % higher than that of ordinary inert electrode. Due to the synergistic effect of the two electrodes, the color of methylene blue can be quickly removed by 99 % in 20 min, and the highest chemical oxygen demand (COD) removal rate can reach 79.5 %. The optimal operation conditions were a pH of 4, a current density of 20 mA cm−2 and an initial concentration of 50 mg L−1. Finally, the degradation pathway of MB was investigated using GC-MS technique and UV absorption spectroscopy. The results suggest that the large organic molecules are continuously cleaved to produce simple aromatic hydrocarbons, which are then destroyed to simple minor organic molecules, ultimately oxidized to CO2 and H2O. This investigation suggests a new idea for the design of an efficient and cost-effective double electrode for the electrocatalytic degradation of dye wastewater.