Excellent Photodegradation Performance Research Articles

Construction of nanocomposite hydrogel by TiO2-carbon quantum dots encapsulated in alginate with a highly efficient adsorption and photodegradation of dye pollutants

This presentation introduces an integrated photocatalyst/adsorbent system, achieved through immobilization and encapsulation of the TiO2 doped with CQDs (carbon quantum dots) nanocomposite within the calcium alginate (CaAlg) matrix. The nanoparticles and nanocomposites were analyzed using various techniques, including FE-SEM, EDX, TEM, XRD, PL, FT-IR, BET, and UV–vis DRS, to determine their structure and properties. The TiO2/CQDs/Alg nanocomposite hydrogel considerably influenced the adsorption and photocatalytic degradation of methylene blue (MB) as a dye pollutant. The adsorption studies were conducted to assess parameters such as adsorption capacity, kinetic behavior, and adsorption isotherms. The outcomes revealed a high adsorption capacity (44.13 mg/g at 90 min) and indicated that the pseudo-second-order kinetic model was highly suitable for describing the adsorption behavior of MB. Moreover, the Freundlich isotherm exhibited better fitting capabilities compared to the Langmuir isotherm. CQDs not only facilitated the transfer of photoelectrons from the TiO2 surface, preventing recombination of electron-hole pairs but also enhanced visible light absorption by the upconversion photoluminescence. The TiO2/CQDs/Alg displayed excellent photodegradation performance (97 %) of MB compared with TiO2 and TiO2/CQDs under visible light due to the abundance of active sites for MB adsorption and photocatalytic reactions. The TiO2/CQDs/Alg hydrogel exhibited excellent reusability in degrading MB for up to five consecutive cycles and showed significant swelling behavior across a broad pH range, reflecting the hydrogel's exceptional stability. The use of charge carrier scavengers indicated that O2˙−radicals were the primary surface species involved in the photodegradation of MB.

A handy way for forming N-doped TiO2/carbon from pectin and d,l-serine hydrazide hydrochloride

N-doped TiO2/carbon composites (N-TiPC) have shown excellent photodegradation performances to the organic contaminants but are limited by the multistage preparation (i.e., preparation of porous carbon, preparation of N-doped TiO2, and loading of N-doped TiO2 on porous carbon). Here, we develop a handy way by combining the Pickering emulsion-gel template route and chelation reaction of polysaccharides. The N-TiPC is obtained by calcinating pectin/Dl-serine hydrazide hydrochloride (SHH)-Ti4+ chelate and is further described by modern characterization techniques. The results show that the N atom is successfully doped into the TiO2 lattice, and the bandgap value of N-TiPC is reduced to 2.3 eV. Moreover, the particle size of N-TiPC remains about 10 nm. The configurations of the composites are simulated using DFT calculation. The photocatalytic experiments show that N-TiPC has a high removal efficiency for methylene blue (MB) and oxytetracycline hydrochloride (OTC-HCL). The removal ratios of MB (20 mg/L, 50 mL) and OTC-HCL (30 mg/L, 50 mL) are 99.41 % and 78.29 %, respectively. The cyclic experiments show that the photocatalyst has good stability. Overall, this study provides a handy way to form N-TiPC with enhanced photodegradation performances. It can also be promoted to other macromolecules such as cellulose and its derivatives, sodium alginate, chitosan, lignin, etc.

Synthesis of novel PdO@Al2O3 nanocomposite for energy storage devices, photodegradation, and other applications

The process for developing PdO@Al2O3 nanocomposites for wastewater treatment involves improving their ability to resist corrosion and their self-cleaning capabilities. To achieve this, it is necessary to carefully combine and analyze different elements to optimize the effectiveness of the catalyst. The objective is to deliver effective and long-lasting solutions for environmental remediation. The PdO@Al2O3 nanocomposite was characterized using FTIR, XRD, SEM, EDS, TEM, UV–Vis, PL, and TGA techniques. The nanocomposites were examined for their photocatalytic activity. The nanocomposite showed significant corrosion resistance and possessed self-cleaning characteristics. The photodegradation of Congo red dye in the aqueous solution was done by using the composite of palladium-aluminum oxides as a catalyst and it revealed excellent photodegradation performance. The photocatalyst degraded the Congo red dye to 98.79 % with a rate constant of 1.5 × 10−2 in a short time of 30 minutes under the irradiation of UV–visible light. The significant band gap in conduction and structure of the core electrostatic field within the p-n heterojunction produces a powerful stimulus for the photogenerated electrons to migrate from PdO to Al2O3 when exposed to visible light. The superior photodegradation of Congo red showed that the heterostructure of the nanocomposite (PdO@Al2O3) exhibited more charge separation with excellent photodegradation proficiency compared to the purely Al2O3 when exposed to visible light. This work represents a significant advancement by providing efficient remedies for wastewater treatment, while also improving the ability to resist corrosion and self-cleaning applications.

Visible-light responsive CuO-ZnO nanostructure synthesized using Muntingia calabura extract for efficient H2O2 evolution and organic pollutant degradation

In this study, ZnO-CuO heterostructures were synthesized via a green approach using Muntingia calabura leaf extract with insights into the precursor ratio for enhanced photocatalytic performance. The synthesized materials were characterized by modern analytic methods, including X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, ultraviolet-visible absorption spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry, which elucidated the presence of CuO nanospheres and ZnO semi-cuboids. Thanks to a lower bandgap of 2.24 eV compared to pristine ZnO (2.82 eV), better visible light absorption, and longer charge lifetime, the optimal ZC16 sample, corresponding to a Cu:Zn ratio of 1:16, achieved a hydrogen peroxide production of 350.23 μM under visible light that was further increased to 478.98 μM with oxygen aeration. In addition, ZC16 also demonstrated excellent photodegradation performance towards malachite green (95.82 %) and tetracycline (97.78 %). Disclosure into the photocatalytic mechanism of both processes revealed the significant roles of active radicals, which have proven the environmentally friendly and cost-efficient synthesis pathway of ZnO-CuO heterostructures for environmental remediation and clean energy applications.

Efficient photocatalytic H2O2 production and photodegradation of RhB over K-doped g-C3N4/ZnO S-scheme heterojunction

Designing efficient dual-functional catalysts for photocatalytic oxygen reduction to produce hydrogen peroxide (H2O2) and photodegradation of dye pollutants is challenging. In this work, we designed and fabricated an S-scheme heterojunction (g-C3N4/ZnO composite photocatalyst) via one-pot calcination of a mixture of ZIF-8 and melamine in the KCl/LiCl molten salt medium. The KCN/ZnO composite produced 4.72 mM of H2O2 within 90 min under illumination (with AM 1.5 filter), which is almost 1.3 and 7.8 times than that produced over KCN and ZnO, respectively. Simultaneously, the KCN/ZnO also showed excellent photodegradation performance for the dye pollutants (Rhodamine B, RhB), with a removal rate of 92 % within 2 h. The apparent degradation rate constant of RhB over KCN/ZnO was approximately 5–8 times that of KCN and ZnO. In the photocatalytic process, photo-generated holes and superoxide radicals are the main active species. Oxygen (O2) was mainly reduced to produce H2O2 via a two-electron (2e−) pathway with superoxide radicals as intermediates and the 2e− oxygen reduction reaction selectivity of KCN/ZnO was close to 69.82 %. Photo-generated holes are mainly responsible for the degradation of RhB. Compared with pure KCN and ZnO, the enhanced photocatalytic activity of the KCN/ZnO composite is mainly attributed to the following aspects: 1) larger specific surface area and pore volume is beneficial to expose more active sites; 2) stronger light harvesting ability and red-shifted absorption edge bestow the compound a stronger light utilization efficiency; 3) the construction of S-scheme heterostructure between KCN and ZnO improve the photogenerated electron-hole pairs separation ability and bestow photogenerated carriers a higher redox potential.

Enhanced desulfurization performance of model fuel by Cu-ZnO/TiO2 heterostructure.

A facile hydrothermal approach was employed to synthesize a novel Cu-ZnO/TiO2 Z-heterojunction with a high density of defects, which was then utilized for the oxidative desulfurization process, demonstrating excellent photodegradation performance. The results showed that by adjusting components such as Cu, ZnO, and TiO2, the removal efficiency of DBT reached 88.12% within a duration of 240 min. In the 5 repeated experiments, 7.5%Cu-ZnO/TiO2 still exhibited high stability and could be reused. The improved photocatalytic performance of the 7.5%Cu-ZnO/TiO2 composite can be attributed to its high light absorption capability and well-matched energy levels, which are due to the abundant presence of imperfections. The adoption of a Z-heterojunction has enabled efficient separation and transfer of photo-generated electrons and holes (e-/h+), thereby reducing the probability of charge carrier recombination.

High-efficient photocatalytic degradation of multiple pollutants by CdPS3 nanosheets

Photocatalytic degradation technique is an effective route for degrading the polluting sources by using photocatalysts. In recent years, van der Waals material based photocatalysts has been drawing more and more attention due to their excellent photodegradation performance. In this research, we have developed a type of highly efficient layered photocatalyst, CdPS3 nano flakes prepared by the liquid-phase exfoliation method. We compared different photodegradation rates of rhodamine B (RhB) by using photocatalysts of CdPS3 ground bulk powder and CdPS3 nanosheets exfoliated by three different dispersants, i.e., N-methyl pyrrolidone (NMP), deionized (DI) water and sodium cholate (SC). For a complete degradation of RhB (80 mL, 100 mg/L), the SC-exfoliated CdPS3 nanosheets exhibited the highest degradation efficiency within 15 min. These SC-exfoliated nanosheets also demonstrated good potential for degrading methylene blue (MB), potassium dichromate (PD), tetracycline (TC) and methyl orange (MO). The strong dark adsorption and dye-sensitized photocatalytic properties of CdPS3 nanosheets could both contribute to high degradation efficiencies of RhB and MB, synergistically. Capture experiments revealed that superoxide radicals dominated the degradations of these pollutants. Additionally, for PD and MO, hydroxyl radicals and holes were also important active species in the photodegradation redox reactions.

Easy Preparation of Zinc Molybdate Photocatalyst and Its Application for Degradation of Methylene Blue

Photocatalyst is one way that can be done to overcome the problem of dye waste in water. Hazardous chemicals are regularly used in the manufacture of photocatalysts. In this research, ZnMoO4 was prepared by an environmentally friendly and cost-effective synthesis. The functional groups, crystalline structure and morphology of ZnMoO4 were characterised using fourier transform infrared (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The band gap energy has been studied through UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). The photocatalytic activity of ZnMoO4 was tested against the organic pollutant methylene blue under visible light irradiation and its degradation products were analyzed with a UV-Vis spectrophotometer at a wavelength of 664 nm. The photocatalytic process of ZnMoO4 has been able to degrade 99% of methylene blue after 80 minutes of irradiation. The excellent photodegradation performance indicates that the transition activity of electron currents from the valence band to the conduction band on ZnMoO4 is going well.

S/P co-doped g-C3N4 with secondary calcination for excellent photocatalytic performance

The metal-free and low-cost g-C3N4 has received a lot of attention from researchers as a photocatalyst to solve environmental and energy problems. However, bulk g-C3N4 suffers from limited light absorption, few reactive sites and easy recombination of photogenerated electrons and holes, resulting in unsatisfactory photocatalytic performance. In this study, g-C3N4 nanosheets with excellent photodegradation performance were successfully fabricated by a combination of S/P co-doping and secondary calcination modifications. The modified g-C3N4 could degrade 99.4% rhodamine B (30 mg L−1) in only 4 min, which was 15 times higher than that of pure g-C3N4 due to the synergistic effect of bi-element doping and secondary calcination. Furthermore, experiments using photocatalytic water splitting for hydrogen production have shown different results, demonstrating that the critical factor is different from the photodegradation reaction.This paper provides an effective and feasible novel idea for the modification of g-C3N4.

Prompt antibacterial activity of silver nanoparticle decorated on HAp embedded NiFe2O4 nanocomposite (NiFe2O4@HAp-Ag) against pathogenic strains and investigation of its photocatalytic activity towards degradation of antibiotics

Local bacterial infection in clinics is still a difficult task and poses serious health threats to human. Systemic antibiotic administration typically results in negative side-effects and bacterial resistance and only has transient antibacterial activity. Several biomedical applications immensely prefer modified hydroxyapatite with excellent biocompatibility and antibacterial characteristics. Herein, we fabricate hydroxyapatite-embedded NiFe2O4 using in situ hydrothermal method and used as a support for silver nanoparticle onto its surface to achieve an effective biological response. The properties of the as-synthesized materials were characterized using several spectroscopic techniques which include X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, ultraviolet–diffuse reflectance spectroscopy spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy. In addition, the magnetic behavior of these nanocomposites was examined using the vibrating sample magnetometer technique. This ternary nanocomposite exhibits potent antimicrobial activity against both Gram-negative bacteria (Pseudomonas aeruginosa and klebsiella pneumoniae) as well as Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus). The MIC or minimum inhibitory concentration, MBC or minimum bactericidal concentration, the disc diffusion, bacterial growth rate, and inhibition rate tests were utilized for the examination of the antimicrobial effect of this synthesized nanocomposite against pathogenic strains. Along with this, we have also investigated its photocatalytic activity toward degradation of cefixime antibiotic under solar light and it shows excellent photodegradation performance. The fabricated nanocomposite demonstrated high reusability with good photostability. Notably, using magnetic decantation this prepared nanocomposite can be easily eliminated from the disinfected medium.

In Situ Construction of Near-Infrared Response Hybrid Up-Conversion Photocatalyst for Degrading Organic Dyes and Antibiotics.

Unique nonlinear optical properties for converting low-energy incident light into high-energy radiation enable up-conversion materials to be employed in photocatalytic systems. An efficient near-infrared (NIR) response photocatalyst was successfully fabricated through a facile two-step method to load BiOBr on the Nd3+, Er3+@NaYF4 (NE@NYF) up-conversion material. The NE@NYF can transform NIR into visible and UV light and promote charge-energy transfer in the semiconductor. Consequently, the as-obtained photocatalysts exhibit excellent photodegradation performance for rhodamine B dye (RhB) and tetracycline (TC) organic pollutants. About 98.9% of the RhB was decomposed within 60 min with the 20% NE@NYF-B sample, outperforming the pristine BiOBr (61.9%). In addition, the 20% NE@NYF-B composite could decompose approximately 72.7% of the organic carbon during a 10 h reaction, which was almost two-fold more than that of BiOBr. Meanwhile, a possible charge transfer mechanism is proposed based on the recombination of electron-hole pairs and reactive oxygen species. This work provides a rational hybrid structure photocatalyst for improving photocatalytic performance in the broadband spectrum and provides a new strategy for NIR light utilization.

Recent Advances in MXenes Based Composites as Photocatalysts: Synthesis, Properties and Photocatalytic Removal of Organic Contaminants from Wastewater

AbstractMXene has indeed gained significant attention in recent years as a promising photocatalyst for various applications, including photocatalytic degradation of pollutants. MXene possesses several unique physical and chemical properties that make it suitable for such applications, including its uniform planar structure, strong metal conductivity, effective functional groups, and numerous derivatives. These properties contribute to the excellent photodegradation performance and long‐term stability exhibited by MXene‐based photocatalysts compared to other photocatalysts. MXene‐based composites, which are formed by incorporating MXene with other materials, demonstrate even better photodegradation activity due to their abundant active sites and porous structure. One crucial factor influencing the photodegradation performance of MXene‐based photocatalysts is the presence of active functional groups on the surface of MXene. These functional groups play a significant role in the photocatalytic process and contribute to the overall efficiency of the catalyst. To provide a broader understanding of MXene‐based photocatalysts, the physicochemical properties of MXene are briefly described in this review. This includes its structural characteristics, electrical conductivity, and the presence of functional groups. This review also investigates the physical and chemical synthesis routes for preparing MXene, both in its natural state and as composites with other materials. These synthesis methods are essential for tailoring the properties of MXene‐based photocatalysts to meet specific requirements. Finally, the review discusses future work and challenges in MXene‐based photocatalysis. This field holds great promise for addressing environmental concerns and improving the degradation of organic compounds. However, further research is needed to optimize the synthesis methods, enhance the photocatalytic efficiency, and explore the practical applications of MXene‐based photocatalysts.

Construction of Bi2MoO6/CoWO4 Z-scheme heterojunction for high-efficiency photocatalytic degradation of norfloxacin under visible light: Performance and mechanism insights

In this work, we employed Bi2MoO6 and CoWO4 to fabricate a direct Z-scheme Bi2MoO6/CoWO4 (BMC-x) heterostructure with high redox potential for norfloxacin (NOR) photodegradation. Under visible light (λ > 420 nm) illumination, BMC-x composites displayed excellent photodegradation performance toward norfloxacin. The photodegradation rate of norfloxacin by BMC-30 reached 97.1% within 60 min of illumination, and the apparent rate constant (0.0588 min−1) was 2.42 and 17.8 times those of Bi2MoO6 and the CoWO4, respectively. The photocatalytic performance of BMC-x nanocomposites was mainly ascribed to the more efficient utilization of electrons (e−) and holes (h+) due to the fabrication of a direct Z-scheme heterostructure. In addition, the mechanisms of NOR degradation were investigated through active species capture experiments and ESR analyses, indicating that O− 2and h+ worked as primary components. Furthermore, the NOR photodegradation pathways were investigated by density functional theory (DFT) and intermediates analysis. More importantly, depending on the QSAR predictions and E.colicultivation, the comprehensive toxicity of the final intermediates was lower than that of the parent. Thus, this work offers a feasible idea for the design and construction of Z-scheme heterojunctions for the highly effective degradation of emerging contaminants in water.

Degradation of Rhodamine B in the photocatalytic reactor containing TiO2 nanotube arrays coupled with nanobubbles

Although photocatalytic technology is applied in water treatment, the challenge still exists due to its low photocatalytic performance. Herein, a photocatalytic reactor coupled with nanobubbles (NBs) is developed to degrade organic pollutants in wastewater. The reactor contains Ti mesh coated with TiO2 nanotube arrays as a photocatalyst. The introduction of NBs in the reactor increases the dissolved oxygen content to enhance photocatalytic performance. The photocatalytic reactor exhibits outstanding photocatalytic performance, and the degradation ability of Rhodamine B is 95.39% after 2 h of irradiation treatment. The reactor also shows excellent photodegradation performance for other organic pollutants, such as methylene blue (74.23%), tetracycline (68.68%), and oxytetracycline hydrochloride (64.10%). Radical trapping experiments further prove that ·O2−, h+ and ·OH are the active species for the degradation of RhB in the photocatalytic system. Therefore, this work provides a feasible strategy to design a photocatalytic reactor coupling with nanobubbles technology for the photodegradation of organic pollutants in wastewater.

Dual defect sites of nitrogen vacancy and cyano group synergistically boost the activation of oxygen molecules for efficient photocatalytic decontamination

Solar-driven photodegradation of pharmaceutical and personal care products (PPCPs) is an attractive strategy for environmental remediation but faces poor activity mainly due to the unsatisfied generation rate of active radicals. Herein, we design and synthesize a hierarchical C3N4 tubes containing dual defect sites of nitrogen vacancy and cyano group (Nv/Cy-tCN) via an alkali-assisted strategy. Density functional theory calculations demonstrate that modification of dual defect sites boost the activation of molecular oxygen through the polarization of O-O bonds. Furthermore, the ability to separate carriers and absorb light can be enhanced by the creation of an electron-rich structure in Nv/Cy-tCN. Consequently, the Nv/Cy-tCN shows excellent photo-degradation performance for eleven types of PPCPs, affording a 100% removal rate toward diclofenac within 7 min of natural sunlight irradiation. The Nv/Cy-tCN system exhibited enhanced diclofenac degradation kinetics with a reaction rate constant of 0.055 min−1, which was 12.8 times higher than that of pristine carbon nitride (0.0043 min−1). Importantly, the impacts on real wastewater and the degradation of trace contaminants further support that this photocatalytic system could be effectively used to remediate PPCPs pollution in environmental waterways.

Dual-functional superwetting CuCo2O4 coated stainless steel mesh for wastewater treatment: Highly efficient oil/water emulsion separation and photocatalytic degradation

Oily water and soluble contaminants from marine oil spills, industrial wastewater and domestic sewage has caused serious water pollution. Although advanced membranes with super-wettability have been used in oil/water separation, most of them lack the capacity to separate oil/water emulsions and remove water-soluble contaminants. Herein, a dual-functional CuCo2O4 nanoneedle array coated stainless steel mesh is successfully fabricated for water purification. The as-prepared mesh shows excellent superhydrophilicity-underwater superoleophobicity and superior anti-oil-fouling capability. The as-prepared mesh can efficiently separate oil/water emulsion and photodegrade soluble organic dyes under UV light irradiation. The as-prepared mesh exhibits the superior oil/water separation emulsion performance with separation efficiency > 99.5% and high flux (172 L m−2 h−1). In addition, the as-prepared mesh possesses excellent photodegradation performance toward organic dyes with a degradation efficiency of more than 96.95%. More importantly, the as-prepared mesh shows durability and stability. The as-prepared mesh has great potential for multi-functional water purification.

Z-scheme Bi4O5Br2/MIL-88B(Fe) heterojunction for boosting visible light catalytic oxidation of tetracycline hydrochloride

Bi4O5Br2/MIL-88B(Fe) Z-scheme heterojunction photocatalyst is fabricated by a facile hydrothermal followed by a coprecipitation method. The heterojunction catalyst greatly improved the visible light utilization and has shown excellent photodegradation performance for tetracycline hydrochloride (TCH). The high oxidation capability, unique charge migration, and enhanced photogenerated charge carrier separation of Z-scheme Bi4O5Br2/MIL-88B(Fe) heterojunction simultaneously contributed to improved catalytic performance. Meanwhile, Z-scheme Bi4O5Br2/MIL-88B(Fe) heterojunction has achieved the highest photodegradation of TCH with ∼93.04 % within 80 min. In addition, the time-resolved photoluminescence (PL) emission decay spectra confirmed a prolonged lifetime of electron excitation with a fluorescence lifetime of ∼1.08 ns compared with Bi4O5Br2 (t = 0.95 ns). Furthermore, following operating conditions, such as pH, solution concentration, various ionic species, etc., the Bi4O5Br2/MIL-88B(Fe) heterojunction has shown excellent photodegradation of TCH in various environmental conditions with high photostability. Additionally, a substantial charge transfer mechanism and TCH photodegradation pathway were explained. This work demonstrates a promising approach to constructing other high-efficiency Z-scheme heterojunction materials for wastewater treatments.

Preparation and application of Bi4O7/Cu-BiOCl heterojunction photocatalyst for photocatalytic degradation of tetracycline under visible light

The construction of heterojunction composites using suitable semiconductor materials is an effective method for the removal of organic pollutants from wastewater. Herein, Bi4O7/Cu-BiOCl nanocomposites were synthesized by hydrothermal and calcination methods as photocatalysts. The morphology, structure, and optical properties of the composites were characterized by SEM, XRD, EDX, FT-IR, DRS, and PL related techniques. Results show that Cu-BiOCl was tightly loaded on the surface of Bi4O7, and the heterojunction was successfully formed between them. The photocatalytic activity of the composites was evaluated by the degradation of tetracycline (TC) under visible light irradiation. It was found that Bi4O7/Cu-BiOCl-2 exhibit excellent photodegradation performance than that of single-phase materials, and the photodegradation efficiency of TC could reach 91% in short time (60 min). Meanwhile, Bi4O7/Cu-BiOCl-2 composite showed high stability and degradation efficiency in simulation experiments with different water sources and inorganic anions doping. The possible degradation pathways were investigated by LC-MS and 3D EEM, and the mechanism was studied using capture experiments and electron spin resonance. Thus, this work provides a new approach for the design of bismuth-based heterojunction photocatalysts.

Sb2X3 (X = S, Se) nanowires/graphene aerogel monoliths for effective photodegradation of dye/drug under visible light irradiation

The visible-light-responsive photocatalysts with high efficiency have been attracting tremendous focus in environmental remediation. Herein, three-dimensional (3D) Sb2X3 (X = S, Se) nanowires/graphene aerogel (Sb2X3/GA) monoliths were prepared by a facile hydrothermal route. The as-prepared Sb2X3/GA monoliths show the shape of a cylinder with a hierarchical porous structure. FESEM and porosimetry analyses revealed that the monoliths have high porosity, large total pore area as well as large pore volume. Sb2X3/GA demonstrated excellent photodegradation performance for the representative anionic/cationic dyes (methyl orange, rhodamine B, and crystal violet) and antibiotic drug (tetracycline hydrochloride) under 120 min of visible light irradiation. The degradation efficiencies of Sb2X3/GA were found to be 92.6–99.8% for the above-mentioned dye/drug, which were much larger than that of the pristine Sb2X3 nanowires. The enhanced photodegradation activity could be ascribed to the synergistic effect between the Sb2X3 nanowires and graphene aerogel, which was confirmed by the results of the photoluminescence and electrochemical impedance spectra. These findings provide an innovative strategy for designing 3D visible-light-responsive photocatalysts for water purification.

Making Pb Adsorption-Saturated Attapulgite with Excellent Photocatalysis Properties through a Vulcanization Reaction and Its Application for MB Wastewater Degradation.

Attapulgite (AT) is a clay mineral with rich reserves in China, and it has good adsorption activity for Pb-containing wastewater. However, as a hazardous waste, the treatment of Pb adsorption-saturated attapulgite was quite difficult. In this work, through a simple vulcanization reaction, the waste Pb adsorption-saturated attapulgite (AT@Pb) was transformed into composite materials (AT@PbS) with good photocatalytic performance. After comprehensive material characterization (including XRD, TEM, XPS, and UV-Vis), the photocatalytic degradation performance and mechanism of AT@PbS for methylene blue (MB) were investigated. The results revealed that AT@PbS was a composite material of attapulgite nanorods (500–600 nm) and nanosquare PbS particles (80–100 nm). Additionally, AT@PbS displayed good visible light absorption, improved photo-electric properties, excellent photodegradation performance for MB, and recycling stability. Moreover, the energy band range of AT@PbS was about −0.043 V to 1.367 V. The photo-generated holes and their derived hydroxyl radicals were the main active species for MB degradation. This work not only provides a new approach to construct the composite photocatalyst, but also demonstrates the possibility of the comprehensive utilization of heavy metal adsorbents for wastewater degradation.