Dye Removal Research Articles

Modified xanthan gum (natural polymeric material) and its derivative for wastewater treatment: A review

AbstractNaturally occurring xanthan gum (XG) has much commercial importance because of its excellent physicochemical, eco‐friendly, and non‐toxic properties. It is used in various applications like protein extraction, wastewater treatment, tissue engineering, drug delivery, food packaging, and so forth. XG is a natural material, and it has some limitations related to the mechanical stress, thermal stability, and hydration. To overcome the limitation, XG can be modified by adding third component or modification of operation for specific applications. XG can be modified by physical, genetically, enzymatically, or chemical processes. Revamped XG also enhances the efficiency toward adsorbing toxic metal ions and organics from synthetic or industrial effluents. The emphasis of present review article is to address the structural characteristics along with the focus on the developing chemically modified XG like grafted, cross‐linked, nanocomposites, and functionally modified biopolymer. However, this review commences thorough discussion on numerous ways of modifications, which can be attempted in XG structure, expanding its applications for heavy metal ion along with dye removal.

Application of Electron Beam Irradiation for the Removal of Dye from Textile Effluents: A Review

Application of Electron Beam Irradiation for the Removal of Dye from Textile Effluents: A Review

Removal of the bemacid blue E-TL using granular activated carbon from abundant biomass: adsorption isotherm, thermodynamic and kinetic studies

In this work, we were interested in the adsorption of an acid dye, Bemacid Blue E-TL by granular activated carbon based on olive stones. To shed light on the adsorption process, batch experiments were performed to study the effect of operating parameters on the adsorption process such as equilibrium time, GAC dose, pH, initial dye concentration, and temperature. The experimental results showed that the adsorption of the dye Bemacid Blue E-TL by GAC based on olive stones depends on the equilibrium time at 8 hours, the pH is 2 of the solution and the dose is 5 g.L-1. To explain the adsorption equilibrium, the experimental values were examined by Langmuir, Freundlich, and Temkin models. The equilibrium is perfectly described by the Langmuir model whose correlation coefficient is higher than 0.99. The maximum retained quantity of the Bemacid Blue E-TL is 55.6 mg.g-1. Different kinetic models such as pseudo-first order, pseudo-second order, and the intraparticle diffusion equation were used to evaluate the adsorption kinetics. The results of the kinetic modeling showed that the pseudo-second order fitted the data well, with a high coefficient of determination (R2 > 0.99) and intra-particle diffusion is not the only rate-limiting step. The thermodynamic parameter values enthalpy (ΔH°), entropy (ΔS°), and energy change (ΔG°) show that the adsorption processes are endothermic and spontaneous. The various results obtained are promising and encouraging to consider a more comprehensive study with the objective of showing that the adsorbent chosen for this study is effective and could be used as a low-cost adsorbent for acid dye removal.

Adsorbent Biomaterials Based on Natural Clays and Orange Peel Waste for the Removal of Anionic Dyes from Water

This study demonstrates the efficient removal of Alizarin Yellow R anionic dye (AY) from aqueous solutions using green adsorbents. Natural kaolin clay (A1), acid-modified natural clay (A2), chemically treated orange peel (C1) and biochar produced by the thermal treatment of orange peel (C2) were tested for the adsorption of AY. The characteristics of the sorbents were determined by instrumental methods: SEM, EDS, FTIR, BET and TGA. The adsorption experiments were performed under different conditions, including the initial AY dye concentration, adsorbent weight, pH, temperature and contact time. The maximum adsorption capacities had values between 15.72 and 74.62 mg/g at 298 K and the optimal pH of 6.5 at initial concentrations ranging from 30 to 70 mg/L for all adsorbents. The equilibrium data were used for the adsorption isotherm models: Freundlich, Langmuir and Temkin. The Freundlich model fit best for the adsorbents A2, C1 and C2, and the Langmuir isotherm had the highest regression value for the adsorbent A1 (R2 = 0.9935). Thermodynamic parameters indicated the spontaneous and favorable adsorption process of AY. A study of the adsorption kinetics proved that they best fit the pseudo-second-order model, with the highest coefficients of determination (R2), outperforming the pseudo-first-order model. The results of this study indicate the potential for the valorization of locally available clays and orange peel waste in the purification processes of water.

Polyphenol Oxidase from Agricultural Wastes for Dye Removal from Wastewater

Polyphenol Oxidase from Agricultural Wastes for Dye Removal from Wastewater

Application of Three-Dimensional Porous Aerogel as Adsorbent for Removal of Textile Dyes from Water

The textile industry is one of the most important industries in the European Union. The main environmental problems of the textile industry are the high water consumption, the generated pollution, the variety of chemicals used and the high energy demand. Recently, adsorbents with a large specific surface area and low weight, such as aerogels, have attracted great interest as promising materials for removing dyes from polluted water. Cellulose aerogels are inexpensive and non-toxic. Langmuir and Freundlich isotherms were chosen as the best method to describe the performance of the adsorbent. In this study, the adsorption efficiency of Congo red, Naphthol green B, Rhodamine B and Methylene blue were determined by using an adsorbent synthesized from paper and cardboard waste. The total organic carbon concentration was chosen as an indicator of the concentration of the dyes in the solutions. The aerogel capsules had 5% cellulose content. It was found that the adsorption capacity of the aerogel in the solutions of Congo red varied from 0.028 mg/g to 14.483 mg/g; in the solutions of Naphthol green B, from 0.013 mg/g to 7.698 mg/g; in the solutions of Rhodamine B, from 0.020 mg/g to 8.768 mg/g; and in the solutions of Methylene blue, from 0.024 mg/g to 13.538 mg/g.

Production and Characterization of Activated Carbon Derived from Costus Afer Leaves (C. afer) for the Adsorption of Methylene Blue Dye from an Aqueous Solution

In this work, Costus afer leaves (C. after) was utilized as an agricultural waste material for the synthesis of activated carbon (AC) used for the adsorption of methylene blue dye from its aqueous solution. The raw material was prepared, chemically activated using KHCO3 with an impregnation ratio of 1:3, and later carbonized at a temperature of 700℃ in an inert N2 atmosphere for 1hour to produce activated carbon. The proximate analysis of the biomass revealed the percentage of ash content, moisture content, volatile matter, and fixed carbon present in the waste biomass. The raw and activated carbon produced were characterized using various tests such as: Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX), Fourier Transform Infrared-(FTIR) Spectrometry, X-Ray Fluorescence (XRF), and Brunauer-Emmett-Teller (BET). The results revealed that the SBET of the biomass increased from 400m2/g to 600m2/g after activation. Adsorption studies were carried out in batch mode to determine the influencing factors of adsorption with varying adsorbent dosage, contact time, and pH values. The adsorption experiment revealed high adsorption efficiency at an optimum parameter of dosage (0.2g), contact time (10 min), and pH (8) with a 70.58% removal of methylene blue dye. An increase in dosage, contact time, and pH above the optimum parameter leads to a decrease in percentage removal. The adsorption capacity was achieved using adsorption isotherm models like Langmuir and Freundlich. Adsorption of methylene blue validated the Langmuir model with an R2 of 0.999 and a Qm of 11.83 mg/g. These results show that activated carbon prepared from Costus afer leaves constitutes an effective low-cost material for the adsorption of Methylene dye from wastewater.

Facile fabrication of sulfonated porous yeast carbon microspheres through a hydrothermal method and their application for the removal of cationic dye

Water pollution containing dyes become increasingly serious environmental problem with the acceleration of urbanization and industrialization process. Renewable adsorbents for cationic dye wastewater treatment are becoming an obstacle because of the difficulty of desorbing the dye from the adsorbent surface after adsorption. To overcome this dilemma, herein, we report a hydrothermal method to fabricate sulfonic acid modified yeast carbon microspheres (SA/YCM). Different characterization techniques like scanning electron microscopy, FTIR spectroscopy, and X-ray diffraction have been used to test the SA/YCM. Decorated with sulfonic acid group, the modified yeast carbon microspheres possess excellent ability of adsorbing positively charged materials. The removal rate of Methyl blue (MB) by renewable adsorbent SA/YCM can reach 85.3% when the concentration is 500 mg/L. The SA/YCM regenerated by HCl showed excellent regeneration adsorption capacity (78.1%) after five cycles of adsorption–desorption regeneration experiment. Adsorption isotherm and kinetic behaviors of SA/YCM for methylene blue dyes removal were studied and fitted to different existing models. Owing to the numerous sulfonic acid groups on the surface, the SA/YCM showed prominent reusability after regeneration under acidic conditions, which could withstand repeated adsorption–desorption cycles as well as multiple practical applications.

Production of Porous Biochar from Cowdung and its Application

Porous activated carbon (PAC) powder is prepared from solid bio-waste - cow dung samples (CD). UV- Spectroscopy confirms the absorption rate of activated porous biochar at different concentration solutions(in ppm).The activation process is carried out by phosphoric acid and sodium hydroxide treatment followed by calcination at different temperature condition. XRD pattern confirms the amorphous phase formation with graphitic nature for different precursor utilization. SEM analysis shows the uniform and hierarchical porous network formation and aggregated particle with tiny. X- ray analysis confirms the formation of graphitic carbon and porous morphology for sample activated at increased calcination temperature. The elemental composition of as prepared carbon samples is determined by SEM and confirms the formation major carbon content existence. The obtained product is observed for the dye removal process wherein the specific amount of PAC is added to the Methylene Blue(MB) dye solutions and the absorption rate is observed through uv-spectroscopy.

A Sustainable and Cost‐Effective Bioadsorbent for the Removal of Allura Red from Contaminated Water

AbstractFood grade dyes pose severe health hazards when consumed in excessive amounts or enter body via contaminated water. Despite its harmful effects, Allura Red (AR) is very less explored dye for its removal, especially using agricultural/fruit waste. This study presents efficient removal of an important and unsafe food grade dye, AR via adsorption. Waste watermelon peel waste has been used for the first time for treatmenting wastewater contaminated with AR. Waste was converted to two types of adsorbents, with and without subjecting it to pyrolysis. Both the adsorbents were characterized for functionality and crystallinity and used for conducting adsorption studies. Removal of dye was evaluated by intrinsic strategy of monitoring the model solutions under pre‐ and post‐adsorption conditions. Removal percentage of dye was determined by calculating its initial (Co) and final (Cf) concentrations in solution using the formula (see Eq. (1)). Various reaction parameters important for adsorption, viz. pH, adsorbent dose, residence time, reaction temperature and particle size were optimized. Results indicate that ~80 % and >92 % dye could be removed using 0.5 g/L adsorbent before and after pyrolysis respectively in 3.5 h from its 2 ppm concentration in modelled water.

Rapidly chemical preparation of Mn doped ZnO nanostructures for photocatalysis efficiency based on UV light system and mechanism insights

Through a facile chemical precipitation process, pure zinc oxide (ZnO) and various ratio of Mn-doped zinc oxide (Zn1-xMnxO) nanostructured materials were synthesized. The degradation of an azo dye acid orange 2 (AO-2) solution under UV light was investigated using the synthesized materials as photocatalysts. XRD, FTIR, DLS, FESEM, EDS, PL, BET, magnetic, TGA and UV–vis techniques were used to elucidate the structural, functional, particle, elemental, morphological, and optical aspects of the catalysts. The XRD and FESEM analysis showed the hexagonal ZnO structure and spherical shape of the ZnO nano-photocatalyst, respectively. The crystal sizes of Zn1-xMnxO are 27.40–38.31 nm. The optical band gap energy of Zn1-xMnxO are 2.53–3.10 eV. Under UV irradiation for 60 min, MZ-25 NPs demonstrated better degradation (100.0%) of AO-2 dye. The effect of various factors such as catalyst quantity, and pH of the dye solution on the rate removal was investigated. After 60 min of UV light irradiation, dye removal was obtained under ideal conditions (with catalyst loading of 3 mgL−1, and pH 4). The rate constant values of MZ-25 sample are determined to be 0.0219 min−1. The scavenging test reveals that ∙O2 − and ∙OH are responsible for the photo-degradation of AO-2 dye.

Fabrication of Monodisperse Magnetic Polystyrene Mesoporous Composite Microspheres for High-Efficiency Selective Adsorption and Rapid Separation of Cationic Dyes in Textile Industry Wastewater.

Sustainable development has become an inevitable trend in the world's green chemical industry for a generation or more. In this study, a monodisperse magnetic polystyrene mesoporous composite microsphere (MPPS) composed of Fe3O4 nanoparticles loaded on polystyrene mesoporous microspheres is introduced. These microspheres serve as effective adsorbents for the swift removal of cationic dyes. The fabrication of the wastewater adsorbent, with its simple operation and economic practicality, involved a combination of dispersion polymerization, a sulfonation reaction, two-step swelling polymerization, and in situ alkaline oxidation technology. Notably, the adsorption capacity within 3 min reaches 184.0 mg/g, with an impressive adsorption efficiency of 92%. This is primarily attributed to the high specific surface area (Smax) of the MPPS providing more reaction sites for π-π interaction. Simultaneously, the attractive force between negatively charged sulfonic acid groups and cationic dyes is enhanced through surface modification of the MPPS. Furthermore, the MPPS, boasting a maximum saturation magnetization of 38.19 emu/g, ensures rapid separation from the solution for recycling within 3 s. Even after 5 cycles, the adsorption efficiency remains over 90%. The rapid separation of dyes is facilitated by the magnetic attraction of Fe3O4 nanoparticles from the MPPS under the application of a magnetic field. These composite mesoporous materials exhibit outstanding performance in both efficient selective adsorption and recyclability, presenting a novel green adsorbent with promising prospects for sustainable development. This innovation is poised to excel in fields such as sewage treatment, separation, and purification.

Green synthesis and studies on citrus medica leaf extract-mediated Au–ZnO nanocomposites: A sustainable approach for efficient photocatalytic degradation of rhodamine B dye in aqueous media

Abstract Incorporating narrow band gap oxide semiconductors and metals into zinc oxide (ZnO) nanostructures broadens the range of light sensitivity to include visible wavelengths. In this study, the photocatalytic degradation of rhodamine B (RhB) dye was studied as a model for environmental pollution in aqueous media. This study describes the use of photodegradation catalysts, including gold (Au), ZnO, and Au–ZnO nanocomposites (prepared in ratios of 90:10 and 95:5) using the extract of Citrus medica leaves. X-ray diffraction (XRD) findings have shown that ZnO nanoparticles (NPs) have a hexagonal wurtzite structure. Field emission-scanning electron microscopy findings have depicted that ZnO NPs have diverse shapes, including spherical, quasi-spherical, hexagonal, and anisotropic, with some clumping. Au exhibits consistent spherical shapes and sizes with even distribution. Au–ZnO (90:10) shows quasi-spherical NPs with interconnected spherical Au, forming a porous and uneven surface. Au–ZnO (95:5) has spherical gold nanoparticles (Au NPs) dispersed on a textured ZnO surface, with some clustering and size variation as evident from the transmission electron microscopy, atomic force microscopy, and diffuse reflectance UV-visible spectroscopy analysis. The characterization results have demonstrated the uniform distribution of Au across the ZnO lattice. Additionally, the XRD patterns confirmed the hexagonal wurtzite structure of ZnO. Furthermore, energy-dispersive analysis of X-ray (EDX)-mapping verified the inclusion of zinc, oxygen, and Au in the hybrid Au–ZnO nanocomposites and their effective distribution. The topological analysis revealed a rough surface for the generated nanostructures. By comparing the results of various techniques, EDX analysis using atomic and weight ratios confirmed the presence of oxygen and Au in the nanocomposite. Additionally, the surface area analysis (BET) test has reported that the adsorption and desorption of nitrogen follow a Type III isotherm. The presence of an H3-type hysteresis loop further confirms the mesoporous nature of the composites, which reports the presence of wedge-shaped pores. The Au–ZnO (90:10) nanocomposite exhibits a higher surface roughness compared to other composites. In addition, this UV-visible diffuse reflectance spectroscopy has enumerated the band gaps of various nanomaterials using UV-visible spectroscopy. Moreover, the analysis has unveiled that combining ZnO with Au NPs (doping) improved the photocatalytic performance of ZnO. This improvement is attributed to the formation of additional energy levels within the ZnO band gap due to the presence of Au ions. Experimental investigation of the breakdown of RhB dye under visible light irradiation revealed superior photocatalytic activity for the Au–ZnO (90:10) nanocomposite compared to both Au–ZnO (95:5) and pure ZnO and Au counterparts. Multiple experiments confirmed the effective photodegradation and removal of RhB dye from the aqueous medium using the nanocatalyst under visible light irradiation. Under optimal conditions (1.0 g·L−1 photocatalyst, 10 ppm RhB, and pH 10), 99% photodegradation efficiency was reached within 50 min of irradiation. Investigation of reactive species revealed that the increased effectiveness of photodegradation in Au–ZnO (90:10) stems from the presence of photogenerated holes and hydroxyl radicals. The study also analyzed the reaction kinetics and order, and the reusability of the best photocatalyst Au–ZnO (90:10)) was confirmed through five consecutive cycles, demonstrating its sustained effectiveness in photodegradation. These findings highlight the potential of Au–ZnO (90:10) nanocomposite as a promising material for photocatalytic degradation of organic dyes.

One‐Step Synthesis of Thiol‐Functional Mesoporous Silica Nanospheres and Selective Removal of Cationic Dyes

AbstractThe surface characteristics of nanoparticles have a huge impact on adsorption effects. In this paper, thiol‐functional mesoporous silica nanospheres (MSNs−SH) are successfully prepared through simple one‐step hydrolysis and co‐condensation of tetraethyl orthosilicate and (3‐mercaptopropyl) triethoxysilane with hexadecyltrimethylammonium bromide and sulfobetaine 12 as dual‐template. The obtained MSNs−SH have high surface area (1260 m2 g−1), accessible mesopores (2.2 nm), great pore volume (1.7 cm3 g−1), and uniform adjustable diameter (90 nm). Furthermore, the diameter and pore‐size of MSNs−SH can be controlled via adjusting the ethanol content in the synthesis system. MSNs−SH exhibit a fast adsorption kinetics, marked adsorption capacity of cationic rhodamine B (RB 534.2 mg g−1), and remarkable selective adsorption for cationic dyes. Theoretical analysis reveals the adsorption behavior of RB on MSNs−SH follows the Langmuir isotherm models and pseudo‐second‐order kinetic. Additionally, the thermodynamic results indicate that the adsorption process is a spontaneous process driven by temperature. The results demonstrate that MSNs−SH are greatly potential for effectively removing cationic dyes from wastewater, with the advantages of simple preparation, high adsorption performance and perfect selectivity.

Removal of Dyes from Water Using Aluminum-Based Water Treatment Sludge as a Low-Cost Coagulant: Use of Response Surface Methodology

The aim of this research was to valorize waste (sludge) from a drinking water treatment plant as a coagulant in the removal of dyes (methylene blue and crystal violet) from water and to prevent environmental issues associated with sludge storage. To accomplish this purpose, the response surface methodology based on a central composite design with five levels was implemented. In order to enhance the efficacy of the coagulation–flocculation process, three key operational variables were considered for optimization: the pH, coagulant dosage (mg/L), and initial dye concentration (mg/L). To achieve this, a quadratic polynomial model was established. According to the mathematical model that has been developed, it is predicted that the highest efficiency for removing dyes is 94.44%. This maximum effectiveness is reached when the pH is adjusted to 12.04, the coagulant dose is set at 87.044 mg/L, and the dye concentration of MB is maintained at 2.955 mg/L. Conversely, the best dye removal of CV was attained at 100% under the following conditions: pH = 12.045, a coagulant dosage of 2.955 mg/L, and a dye concentration of 2.955 mg/L. The R2 (98.44% and 95.80% for MB and CV, respectively) validated both models. In this work, the coagulant was characterized by the surface charge, FTIR, BET, and SEM analysis.

Eriochrome Black T dye removal from an aqueous solution using graphene oxide-modified activated carbon materials

ABSTRACT The presence of a toxic anionic dye, like Eriochrome Black T (EBT) in the aquatic environment, is the major cause of water contamination. Considering this, we synthesised activated carbon, (AC) derived from the Carica papaya seeds, which is effective, low-cost, simple to design and with a higher surface area. The prepared materials (GO/AC) will be employed for the efficient removal of toxic EBT dye. The synthesised GO/AC composite was further analysed using FTIR, XRD, FE-SEM, EDX and Raman spectra. The adsorption performance of GO/AC materials towards EBT dye removal was checked through a batch adsorption experiment. Various parameters, including initial dye concentration, contact time, adsorbent dosage, stirring speed and pH, were batch-wise varied for the adsorption experiment. The higher correlation coefficient (R 2 = 0.99) indicated that the Langmuir isotherm model was followed by the experimental data suggesting that the adsorption process is a monolayer. The maximum adsorption capacity of EBT dye was found to be 51.84 mg/g. The pseudo-second-order kinetic model was well-fitted. The thermodynamic study suggested that the adsorption process is endothermic and spontaneous. Furthermore, the desorption efficiency of the GO/AC materials was tested through reusability in five cycles. An adsorption mechanism was also performed for the removal of EBT dye.

A Novel Method for the Highly Effective Removal of Binary Dyes from Colored Dyeing Wastewater by Periodic Reversal/Direct Current-Activated Persulfate

In recent years, electrochemical synergistic activation of persulfate (PDS) degradation technology has demonstrated significant potential in wastewater treatment applications. Given the challenges posed by the complex water quality, high COD content, and recalcitrant degradation of dyeing wastewater, this study aimed to evaluate the efficacy of iron/aluminum dual-electrode electrochemical activation of PDS for degrading simulated dyeing wastewater. The results showed that under optimal conditions, utilizing both periodic reversal and direct current electrochemical activation of PDS achieved removal rates of 99.2% and 98.3% for Reactive Black 5 (RB5) and Reactive Red X-3B (RRX-3B), respectively, demonstrating promising removal efficiency. Notably, the removal efficiency of RB5 surpassed that of RRX-3B, suggesting a dependence on initial concentration influencing reaction kinetics. Furthermore, full-spectrum scanning and quenching experiments revealed that RB5 and RRX-3B were primarily degraded through the potent oxidation action of SO4−· and ·OH, with a small number of intermediates present in the solution. Periodic reversal proved effective in mitigating electrode passivation and enhancing electrode longevity. This study provides a highly effective removal method of binary dyes from dyeing wastewater by periodic reversal Fe-Al dual-electrode electrochemical activation of PDS technology, offering valuable insights for sustainable treatment of dyeing wastewater with binary components.

Photocatalytic application of nickel oxide/zinc oxide nanoparticles decorated kaolinite nanocomposite for the degradation of crystal violet

The photocatalysis process, which is effective, economical, and environmentally friendly can overcome rapidly increasing environmental problems, has shown rapid development in recent years. Nontoxic, low-cost natural minerals are often used in photocatalysis processes that remove organic pollution from wastewater. In this study, a selective method for the removal of crystal violet (CV) from aqueous solutions using nanocomposite of nickel oxide/zinc oxide nanoparticles (NiO/ZnO) supported on kaolinite photocatalyst was investigated. The raw kaolinite, bare NiO, bare ZnO and nanocomposite samples were characterized by the XRD, TEM, SEM-EDX, XPS and FTIR techniques. The photocatalytic performances of kaolinite-NiOZnO (K-NiO/ZnO) nanocomposite and bare samples were also investigated and comparatively evaluated by the photodegradation of CV (cationic dye) dye under visible light irradiation. The effects of various parameters such as the dosage of photocatalysis, contact time, and initial dye concentration on the rate of removal of dye were investigated and optimized. The kinetics of decolorization by samples can be well described by the pseudo-first-order model. Finally, it can be used in advanced oxidative processes for the degradation of organic pollutants.

Research upon Cu-Doping Contents in TiO2 Nanoparticles Incorporated onto Cellulose Nanofibers for Dye Removal and Self-Cleaning Applications

Research upon Cu-Doping Contents in TiO₂ Nanoparticles Incorporated onto Cellulose Nanofibers for Dye Removal and Self-Cleaning Applications

Integration of hydrogen evolution and dye removal in flexocatalysis by centrosymmetric semiconductor nanorods

In this work, coupling of the hydrogen (H2) production and dye degradation was first realized in a single flexocatalytic process using cerium oxide nanorods (CeO2 NRs). The flexoelectric polarization in a bending nanorod created an internal electric field, which promoted the separation of the thermal-excited electrons and holes. As a consequence, the H2 evolution rate of the flexocatalysis in dark was twice higher than that of the photocatalysis by the same CeO2 NRs. Moreover, simultaneous dye degradation was realized without reducing the H2 evolution rate, with the degradation constant rate of 0.065 min−1, dye removal efficiency of 89.3%, and H2 generation at 486.4 μmol g−1 h−1. The dual-functional catalytic performance of the CeO2 NRs was benefited from the unique periodic flexoelectric field induced by the ultrasound vibration, which could not be achieved by photocatalysis. This work revealed the important role of flexoelectric effect in overcoming the limitation in photocatalysis, which could be extended to a wide range of semiconductor nanomaterials for designing novel kinds of advanced flexocatalysts.