Photocatalytic Degradation Of Indigo Carmine Research Articles

Construction of coordination polymer [Ni(ppda) (tib) (H2O)]·H2O and photocatalytic degradation of indigo carmine

Semiconductor coordination polymers have garnered significant attention as photocatalysts for wastewater treatment owing to their adaptable structure, expansive specific surface area, and outstanding selectivity, stability, and sensitivity. In this study, coordination polymer [Ni(ppda) (tib) (H2O)]·H2O was synthesized utilizing flexible phenyldiacetic acid (H2ppda) and rigid 1,3,5-tris(1-imidazolyl)benzene (tib). Crystal structure analysis revealed that the three-linked tib ligands and the central Ni(II) ion create a wavy 2D surface. Additionally, cis-ppda2- ligands form a 1D wave chain alongside central Ni(II), which traverse through a 2D layer. Adjacent layers are interlaced via ppda2−, resulting in a complex 3D supramolecular structure. The fundamental framework of [Ni(ppda) (tib) (H2O)]·H2O exhibits stability up to 316 °C and remains stable over 5 cycles, with a band gap energy of 2.9 eV, rendering it a viable candidate for catalytic applications. In aqueous systems, [Ni(ppda) (tib) (H2O)]·H2O demonstrates efficient photocatalytic degradation of Indigo Carmine (IC), achieving a degradation rate of 98.5% and a reaction rate of 0.027 min−1, showcasing commendable selectivity and semiconductor properties. The primary photocatalytic degradation mechanism involves the synergistic formation of ·OH and ·O2- active species through the interaction between [Ni(ppda) (tib) (H2O)]·H2O and H2O2, facilitating the oxidative degradation of dye molecules.

Effectiveness of Ag@NiO@g-C3N4 photocatalysts: Green fabrication and superior photocatalysis capability

A novel nanocomposite material, Ag@NiO@g-C3N4, was synthesized using ultrasonic irradiation with Ag@NiO as precursor materials. X-ray diffraction (XRD) analysis confirmed the formation of g-C3N4 and anatase Ag@NiO phases within the nanocomposite. Transmission electron microscopy (TEM) imaging revealed the deposition of Ag@NiO nanoparticles onto g-C3N4 layers. X-ray photoelectron spectroscopy (XPS) verified the presence of C, N, O, Ni, and Ag in the nanocomposite. The synthesized nanocomposite exhibited a significantly increased surface area of 94.705 m2/g and a reduced energy band gap of 3.07 eV. The photocatalytic activity of NiO nanoparticles, Ag@NiO nanoparticles, g-C3N4 nanosheets, and the Ag@NiO@g-C3N4 nanocomposite was evaluated under visible light irradiation. The Ag@NiO@g-C3N4 nanocomposite demonstrated superior photocatalytic performance compared to the individual components. The photocatalytic degradation of indigo carmine (IC) dye was used to assess the photocatalytic activity, and the Ag@NiO@g-C3N4 nanocomposite exhibited exceptional efficacy exhibited a significantly higher reaction rate, estimated to be approximately 100 times faster than the unmodified process. This observation implies that the Ag@NiO@g-C3N4 nanocomposite exhibits potential as a viable material for various environmental applications.

Luminescence and photocatalytic degradation of indigo carmine in the presence of Sm3+doped ZnS nanoparticles

Industrial wastewater discharge is well acknowledged to constitute a significant environmental and public health risk. In addition, synthetic dyes used in the textile sector are major culprits in water pollution. The amount of water polluted by these dyes is simply staggering. We urgently address this issue to protect our planet and health. The degradation of indigo carmine dye in the presence of Sm3+-doped ZnS nanoparticles is reported in this study and characterized by XRD, FTIR, SEM, EDX, TEM, BET, PL, UV, etc. The particle size calculated from the Scherrer equation was 3–12 nm. When excited at 395 nm, Sm3+ undergoes f–f transitions, which are visible as prominent peaks in the photoluminescence spectrum at 559, 595, and 642 nm wavelengths. The catalyst showed vigorous catalytic activity for dye degradation, with a 93% degradation rate when used at 15 mg/L catalyst within 210 min. The reaction was found to have pseudo-first-order kinetics. After applying the Freundlich and Langmuir data, the Langmuir isotherm offered the best fit. The findings indicate that the Sm3+-doped ZnS catalyst might be successfully used in the degradation of dyes present in the environment. Doping with Sm3+ ions can significantly change the photocatalytic breakdown of indigo carmine and the luminescence characteristics of ZnS.

Environmental remediation promoted by silver nanoparticles biosynthesized by eucalyptus leaves extract

A simple and low-cost green synthesis method was optimized to prepare stable silver nanoparticles (AgNP) using aqueous Eucalyptus globulus leaves extract. This green method allows to obtain AgNP with spherical morphology and variable size around 25 nm, and it is dependent of the reaction temperature and concentration of the plant extract. AgNP stability was followed during 3 months by zeta potential measurements and a negative zeta range from −30.7 to −33.6 was determined. Biogenic-stabilized AgNP exhibited dual-functional properties as effective in environmental remediation with bacterial growth inhibition and dye photodegradation. Staphylococcus aureus and Escherichia coli were tested for antibacterial activity, and considerable inhibitory activity was found. High photocatalytic degradation of indigo carmine (IC) dye was performed in the presence of the AgNP as catalysts under sunlight irradiation. The degradation efficiency after 2 h of reaction was 37 %, 83 % and 98 % in the presence of UV light, visible light and sunlight irradiation, respectively. The germination of corn kernels test was used to determine the toxicity of the treated IC solutions and the results showed low toxicity after the photodegradation process.

TiO2-CoFe2O4 and TiO2-CuFe2O4 Composite Films: A New Approach to Synthesis, Characterization, and Optical and Photocatalytic Properties

Here, we report a new simple and fast method of cobalt and copper ferrites film fabrication on the Ti/TiO2 surface. The approach is based on the deposition of gelatin gel containing copper and cobalt nitrates on the surface of porous oxide-silicon coatings on titanium obtained by plasma electrolytic oxidation (PEO) followed by two-stage annealing at 300 °C and 800 °C to yield ferrite films with good adhesion to PEO layer. The presence of Co/Cu ferrite phases was confirmed by EDX analysis, XRD, and Mössbauer spectroscopy. TiO2-CoFe2O4 and TiO2-CuFe2O4 composite films have excellent performance in the photocatalytic degradation of indigo carmine as a model dye at pH 3 under UV and visible irradiation. The suggested approach to obtain ferrite/TiO2 composite films is promising for the development of magnetic materials, sensors, catalysts, and photocatalysts for various applications.

Pulsed laser-induced dewetting to fabricate Au-Pd nanoparticles supported on ZnO films and its application for the photocatalytic degradation of indigo carmine

Gold-palladium (Au-Pd) bimetallic alloy nanoparticles (NPs) were obtained by the interaction of a laser pulse with a stack of Au and Pd thin films, these films were previously and sequentially deposited on a zinc oxide (ZnO) thin films grown on a glass substrate. This method can produce, with a single laser pulse, spherical NPs of different compositions which remain attached to the surface of the ZnO film. X-ray diffraction analysis showed that the NPs are composed of a solid solution of the metals whose relative content was modified by varying the deposition time of the starting metal films. The higher amount of Pd in the NPs, the smaller particle size being the minimum around 50 nm. To demonstrate the usefulness of this method to produce Au-Pd NPs directly on surfaces, the decorated ZnO layers were tested as photocatalysts material for the decomposition of indigo carmine dye. The bimetallic NPs supported on ZnO showed to have a better photocatalytic performance to decompose the dye than their mono-metallic counterpart and bare ZnO thin film. The bimetallic NPs richer in Pd achieved a degradation of 99% of the dye while bare ZnO film reached just 32%.

Preparation of mesoporous ThO2 nanoparticles: Influence of calcination on morphology and visible-light-driven photocatalytic degradation of indigo carmine and methylene blue

The present article reports the synthesis of thoria nanoparticles (ThO2 NPs) via sol-gel process and examines the effect of calcination temperature of ThO2 on the morphology and photocatalytic degradation of indigo carmine (IC) and methylene blue (MB) under visible-light. As-synthesized white crystals of ThO2 were subjected to calcination at different temperatures, viz. 700 °C (TH-700), 800 °C (TH-800), and 900 °C (TH-900). The effect of calcination temperature on the structural, morphological, thermal, surface area-porosity, and optical properties of ThO2 NPs were investigated by diverse analytical techniques. XRD patterns show the cubic-space group Fm-3m (225) with parameter a = 5.597 Å and reveals crystallite sizes increased with calcination temperature. The bandgap energy was found to be 1.85 eV, 2.33 eV, and 2.71 eV for TH-700, TH-800, and TH-900 NPs, respectively, calculated by Kubelka-Munk (KM) plot. SEM and TEM unveil that the sample TH-700 calcined at a low temperature of 700 °C yields assembled nanosheets, while at higher temperatures, i.e., 800 °C (TH-800) and 900 °C (TH-900), produces agglomerated nanomaterials. Further, TH-700 sample exhibits enhanced photocatalytic degradation within 120 min for both IC and MB dye than TH-800 and TH-900 counterparts. Among the dyes, IC shows improved photocatalytic efficiency than MB for TH-700, owing to the increased optical absorption and improved separation of photogenerated charge carriers. The reusability study of TH-700 reveals that the catalysts were stable up to four successive cycles with no drastic changes in photocatalytic efficiency. Also, systematic photodisintegration of IC was investigated by Liquid chromatography–mass spectrometry (LC–MS).

Preparation and Property Characterization of In2YSbO7/BiSnSbO6 Heterojunction Photocatalyst toward Photocatalytic Degradation of Indigo Carmine within Dye Wastewater under Visible-Light Irradiation.

In2YSbO7 and In2YSbO7/BiSnSbO6 heterojunction photocatalyst were prepared by a solvothermal method for the first time. The structural characteristics of In2YSbO7 had been represented. The outcomes showed that In2YSbO7 crystallized well and possessed pyrochlore constitution, a stable cubic crystal system and space group Fd3m. The lattice parameter of In2YSbO7 was discovered to be a = 11.102698 Å and the band gap energy of In2YSbO7 was discovered to be 2.68 eV, separately. After visible-light irradiation of 120 minutes (VLGI-120M), the removal rate (ROR) of indigo carmine (IC) reached 99.42% with In2YSbO7/BiSnSbO6 heterojunction (IBH) as a photocatalyst. The ROR of total organic carbon (TOC) reached 93.10% with IBH as a photocatalyst after VLGI-120M. Additionally, the dynamics constant k which was taken from the dynamic curve toward (DCT) IC density and VLGI time with IBH as a catalyst reached 0.02950 min−1. The dynamics constant k which came from the DCT TOC density and VLGI time with IBH as a photocatalyst reached 0.01783 min−1. The photocatalytic degradation of IC in dye wastewater (DW) with IBH as a photocatalyst under VLGI was in accordance with the first-order kinetic curves. IBH was used to degrade IC in DW for three cycles of experiments under VLGI, and the ROR of IC reached 98.74%, 96.89% and 94.88%, respectively, after VLGI-120M, indicating that IBH had high stability. Compared with superoxide anions or holes, hydroxyl radicals possessed the largest oxidative ability for removing IC in DW, as demonstrated by experiments with the addition of trapping agents. Lastly, the probable degradation mechanism and degradation pathway of IC were revealed in detail. The results showed that a visible-light-responsive heterojunction photocatalyst which possessed high catalytic activity and a photocatalytic reaction system which could effectively remove IC in DW were obtained. This work provided a fresh scientific research idea for improving the performance of a single catalyst.

Preparation of Silver Decorated Reduced Graphene Oxide Nanohybrid for Effective Photocatalytic Degradation of Indigo Carmine Dye

Background: Even though silver decorated reduced graphene oxide (Ag-rGO) shows maximum absorptivity in the UV region, most of the research on the degradation of dyes using Ag-rGO is in the visible region. Therefore the present work focused on the photocatalytic degradation of indigo carmine (IC) dye in the presence of Ag-rGO as a catalyst by UV light irradiation. Methods: In this context, silver-decorated reduced graphene oxide hybrid material was fabricated and explored its potential for the photocatalytic degradation of aqueous IC solution in the UV region. The decoration of Ag nanoparticles on the surface of the rGO nanosheets is evidenced by TEM analysis. The extent of mineralization of the dye was measured by estimating chemical oxygen demand (COD) values before and after irradiation. Results: The synthesized Ag-rGO binary composites displayed excellent photocatalytic activity in 2 Χ 10-5 M IC concentration and 5mg catalyst loading. The optical absorption spectrum of Ag-rGO showed that the energy band-gap was found to be 2.27 eV, which is significantly smaller compared to the band-gap of GO. 5 mg of Ag-rGO was found to be an optimum quantity for the effective degradation of IC dye. The degradation rate increases with the decrease in the concentration of the dye at alkaline pH conditions. The photocatalytic efficiency was 92% for the second time. Conclusion: The impact of the enhanced reactive species generation was consistent with higher photocatalytic dye degradation. The photocatalytic mechanism has been proposed and the hydroxyl radical was found to be the reactive species responsible for the degradation of dye. The feasibility of reusing the photocatalyst showed that the photocatalytic efficiency was very effective for the second time.

Photocatalytic degradation of indigo carmine by using tungsten doped bismuth vanadate

The photocatalytic degradation of indigo carmine dye was studied using tungsten doped BiVO4. Bismuth vanadate powder has been synthesized by sol-gel technique. The incorporation of W ions into BiVO4 was confirmed by EDX. The photocatalytic activity was studied using different samples of BiVO4 by variation of pH, concentration of dye, dose of semiconductor and light intensity. It has been found that degradation of dye is more effective in presence of W doped BiVO4, It shows the role of tungsten ions for enhancing degradation of indigo carmine by reducing the recombination of photogenerated electrons and holes.

Investigation on the photocatalytic activity of chemically synthesized zirconium doped cadmium selenide nanoparticles for indigo carmine dye degradation under solar light irradiation

A simple chemical methodology has been adopted for the synthesis of zirconium (Zr) doped and un-doped cadmium selenide (CdSe) nanoparticles for the application towards photocatalytic degradation of indigo carmine (IC) dye under solar light irradiation. The as prepared Zr-CdSe (doped) and CdSe (un-doped) nanoparticles were characterized by ultraviolet visible spectroscopy (UV-vis), X-ray diffraction (XRD), Scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDAX) and Transmission electron microscopy (TEM) studies. The inclusion of Zr ion into the CdSe nanoparticles matrix was confirmed by SEM-EDAX and XRD studies. TEM studies confirm the zirconium ions are uniformly doped over the CdSe surface. The photocatalytic degradation performance of Zr doped and un-doped CdSe nanoparticles were examined for the degradation of IC dye under solar light irradiation. The experimental results showed that the Zr doped CdSe possessed greater photocatalytic activity in comparison to un-doped CdSe. Photodegradation process parameters such as the initial concentration of the dye, as well as the amount of catalyst and time were investigated. The photocatalytic degradation rate was favored by a high concentration of solution in respect to Langmuir–Hinshelwood model.

Sunlight-induced photocatalytic degradation of indigo carmine using Bi5Ti3FeO15 layered structure

A sample of an Aurivillius structure formulated as Bi5Ti3FeO15 was prepared via a simple co-precipitation of Bi(NO3)3, Ti(OEt)4 and FeCl3 salts and was characterized based on XRD, FE-SEM, EDS, FT-IR, Uv–vis, DRS, BET and VSM techniques. The XRD pattern shows an orthorhombic phase of Bi9Ti6FeO27. The crystallite size of the sample was estimated by the Scherrer equation (55 nm) and the Williamson-Hall (W–H) (45 nm) methods. The micro strain (ε) and dislocation density (δ) values were determined using W-H method as 0.0297 and 4.94*10−4 respectively. The band-gap energy of Bi5Ti3FeO15 was determined by the Tauc equation from its DRS analysis as 2.03 eV. The sample shows reasonable magnetic parameters Ms =2.003 emu/cc, Mr = 0.95 emu/cc, and Hc =30 Oe. Finally, the photocatalytic degradation of indigo carmine was investigated by Bi5Ti3FeO15 nanostructure under natural sunlight irradiation condition. The maximum degradation of indigo carmine was achieved at pH = 4, catalyst dosage (0.06 g) and pigment concentration (30 ppm).

The oligomer approach: An effective strategy to assess phenylene vinylene systems as organic heterogeneous photocatalysts in the degradation of aqueous indigo carmine dye

Four oligo-phenylenevinylenes (OPVs) were synthesized by the Mizoroki-Heck cross-coupling reaction to provide a deeper understanding of the mechanism and fate of phenylenevinylene systems when applied to the heterogeneous photocatalytic degradation of indigo carmine (IC) dye in aqueous media. OPVs displayed visible light absorption near 500 nm and appreciable emission properties. The stability, mechanism, and photodegradation activity of the OPV systems over aqueous indigo carmine were investigated using radical scavengers, a singlet oxygen (1O2) trap, and ESI-IT-MS. It was confirmed that superoxide radical (O2·−), 1O2, and direct oxidation are responsible for dye degradation. Hydroxide radical formation, under neutral pH conditions, does not occur, and it was corroborated by the HOMO and LUMO levels of the photocatalysts. Additionally, the use of oxalic acid as an electron sacrificial donor was demonstrated as an effective approach to enhance the OPVs photocatalytic activity. However, a significant decrease in activity during the first three irradiation cycles was observed, indicating that the enhancement in photo- and chemical stability is required for further dye-contaminated water treatment applications.

High photocatalytic activity of TiO2/Fe2O3 nanocomposite prepared by impregnation method for degradation of indigo carmine

The photocatalytic degradation of indigo carmine (IC) dye was carried out by using TiO2/Fe2O3 nanocomposite prepared by impregnation method under UV light irradiation. The effect of TiO2 to Fe2O3 mole ratio on the properties and photocatalytic activity of TiO2/Fe2O3 nanocomposite was studied by the prepared three series of TiO2/Fe2O3 nanocomposites with TiO2 to Fe2O3 mole ratio of 1:3, 1:1 and 3:1. The characterization of TiO2/Fe2O3 nanocomposite by XRD showed that the iron (III) oxide extracted from iron ore and calcined at 700°C was in hematite phase (a-Fe2O3). The photocatalytic activity of TiO2/Fe2O3 nanocomposites was determined by using 6 W UV lamps with the wavelength 365 nm and the degradation efficiency of indigo carmine was determined based on UV-Vis spectrophotometer data. The TiO2/Fe2O3 nanocomposite with the the mole ratio of TiO2 to Fe2O3 1:3 showed higher photocatalytic activity than other mole ratio and bare Fe2O3. Degradation efficiency also was highly affected by the initial pH of IC solution, photocatalyst dosage and initial IC concentration. The maximum experimental degradation efficiency of IC was achived at pH value 1 using 0.35 g of photocatalyst and at 20 ppm of initial IC concentration after being irradiated by UV light for 120.

ZnO-Bi2O3/graphitic carbon nitride photocatalytic system with H2O2-assisted enhanced degradation of Indigo carmine under visible light

Indigo carmine in aqueous solution was effectively degraded using ZnO-Bi2O3/Graphitic Carbon Nitride heterojunction structure by visible light/H2O2 system. The mechanism of photocatalytic degradation of Indigo carmine shows the responsible species for the degradation of Indigo carmine in the ZnO-Bi2O3-xC3N4/H2O2/visible light system (x = 0, 1, 2, and 3) is the hydroxyl radicals which were generated from the reaction of e− and h+ with H2O2. Under optimal conditions, ZnO-Bi2O3-2C3N4/H2O2/Vis system degraded more than 93% of Indigo carmine in 180 min. Besides, the kinetic of the photocatalytic process was detailed. These results demonstrate that the ZnO-Bi2O3-2C3N4/H2O2/visible light system may become a promising approach to achieve efficient environmental remediation as an environmentally friendly oxidant.

Graphene oxide–nano‐titania composites for efficient photocatalytic degradation of indigo carmine

Nano‐titania composites assembled with variable weight percentages (wt%) of graphene oxide (GO) were synthesized, and their effectiveness as photocatalysts was investigated for the degradation of indigo carmine under visible light irradiation. Controlled hydrolysis of titanium tetrachloride (TiCl4) was performed in aqueous medium, and 1% aqueous solution of GO was added under ultrasonication. Depending on the wt% of GO, the materials were designated as 1, 2, 5, 10, 15 wt%GO–nano‐titania (GO–NT) composites. Their morphology and structural properties were characterized using X‐ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), high‐resolution transmission electron microscopy (HRTEM), and field‐emission scanning electron microscopy (FE‐SEM). Excellent photocatalytic activity was demonstrated by the NT composite containing 10%GO in 60 min, and the required optimum conditions were established.

Photocatalytic degradation of indigo carmine by ZnO photocatalyst under visible light irradiation

In this work, the photocatalytic degradation of indigo carmine (IC) using zinc oxide suspension was studied. The effect of influential parameters such as initial indigo carmine concentration and catalyst loading were studied with the effect of Vis irradiation in the presence of reused ZnO was also investigated. The increased in initial dye concentration decreased the photodegradation and the increased catalyst loading increased the degradation percentage and the reused-ZnO exhibits lower photocatalytic activity than the ZnO catalyst. It has been found that the photocatalytic degradation of indigo carmine obeyed the pseudo-first-order kinetic reaction in presence of zinc oxide. This was found from plotting the relationship between ln (C0/Ct) and irradiation the rate constant of the process.UV- spectrophotometer was used to study the indigo carmine photodegradation.

Synthesis, characterization, and photocatalytic activity of N-doped carbonaceous material derived from cellulose in textile dye remediation

N-doped carbonaceous materials were synthesized by pyrolysis of microcrystalline cellulose and urea at 900°C. The pyrolyzed materials were characterized via SEM, XPS, STEM/EDX, and FT/IR. Microscopy images revealed wrinkled sheet-like morphology with stacked graphitic layers, and elemental analyses confirmed 7.74% nitrogen content, which was evenly distributed throughout the material. The characteristic peaks of CN and CN bonds in FT/IR indicated N-atom incorporation in the material. The catalytic experiment with alcian blue 8Gx dye under visible light showed higher degradation than in dark, which illustrated the photocatalytic nature of the material. The pH conditions and material ratios were optimized during the photocatalytic experiments. Various dyes were subjected to degradation photocatalytically using the materials at pH 5.5 and recyclability studies indicated multi-cycle use of the material. Additionally, kinetic studies of the photocatalytic degradation of indigo carmine showed that the disappearance of the dye followed a first-order kinetics. The significance of adsorption phenomena in the process of degradation was established by comparing the adsorption constant (KLH=0.898Lmg−1) calculated using the Langmuir-Hinshelwood model with that calculated based on the adsorption isotherm model (KL=0.2457Lmg−1). Degradation products were characterized via various analytical techniques, including GC–MS, ion chromatography, FT/IR, and total organic carbon analyses. Furthermore, the role of oxygen and radical quenchers were studied and it was found that the main species responsible for dye degradation was hydroxyl radical. N-doping of cellulose via a simple pyrolysis method has therefore been proven to be effective in development of photocatalytic materials for pollutant mitigation.

Photocatalytic degradation of indigo carmine by ZnO photocatalyst under visible light irradiation

In this work, the photocatalytic degradation of indigo carmine (IC) using zinc oxide suspension was studied. The effect of influential parameters such as initial indigo carmine concentration and catalyst loading were studied with the effect of Vis irradiation in the presence of reused ZnO was also investigated. The increased in initial dye concentration decreased the photodegradation and the increased catalyst loading increased the degradation percentage and the reused-ZnO exhibits lower photocatalytic activity than the ZnO catalyst. It has been found that the photocatalytic degradation of indigo carmine obeyed the pseudo-first-order kinetic reaction in presence of zinc oxide. This was found from plotting the relationship between ln (C0/Ct) and irradiation the rate constant of the process.UV- spectrophotometer was used to study the indigo carmine photodegradation.

Cr/S/TiO2-loaded hollow glass microspheres as an efficient and recyclable catalyst for the photocatalytic degradation of indigo carmine under visible light

Chromium and sulfur co-doped nanometer TiO2 hollow glass microspheres (Cr/S/TiO2-HGM) were synthesized by a sol-gel method. Characterization used X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), N2 adsorption-desorption (Brunauer-Emmett-Teller (BET) measurements) and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activity was evaluated by photodegradation of indigo carmine in an aqueous solution under visible light irradiation. The results indicated that the Cr/S/TiO2 containing 0.60% (atomic ratio) chromium and 1.2% (atomic ratio) sulfur calcined at 500 oC for 2 h had high catalytic efficiency under visible light irradiation. The floating Cr/S/TiO2-HGM catalyst had greater photocatalytic activity than Cr/S/TiO2 powder. Therefore, Cr/S/TiO2-HGM is a promising, high-performing, visible-light-driven, and more reusable photocatalyst.