Catalytic Activity For Degradation Research Articles

Cobalt based bimetallic catalysts for heterogeneous electro-Fenton adapting to vary pH for HEDP and MIT degradation

ABSTRACT Most of the materials studied as catalysts in the electro-Fenton system are variants of iron oxide or iron hydroxide. However, iron-based catalysts often exhibit weak catalytic capabilities under neutral and alkaline conditions. In this work, we synthesized three cobalt based bimetallic oxides, Co2CuOx, Co2AlOx, and Co2NiOx, using hydrothermal method and evaluated them as catalysts for the heterogeneous electro-Fenton system to remove 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) and Methylisothiazolinone [2-methyl-4-isothiazolin-3-one] (MIT). Co2NiOx has the highest catalytic degradation activity for HEDP, and Co2CuOx has the best catalytic degradation effect for MIT. Based on characterization results of the catalysts, the reasons for the differences in the pollutant removal efficiency were analysed, and the optimal pH for the three cobalt based oxides to remove HEDP and MIT was investigated. The results showed that the optimal pH values of the three cobalt based bimetallic oxides are not only influenced by the second metal type, but also by the properties of pollutants. Therefore, suitable cobalt based catalysts can be selected based on the different properties of pollutants, or the composition of cobalt based catalysts can be adjusted to meet the different pH requirements of target wastewater. The three cobalt based bimetallic oxides exhibited good degradation of HEDP and MIT under neutral conditions, which to some extent solved the problem of narrow pH range in the practical application of the electro-Fenton process.

Modulating pollutant adsorption and peroxymonosulfate activation sites on Co3O4@N,O doped-carbon shell for boosting catalytic degradation activity

The construction of double active sites for pollutant adsorption and peroxymonosulfate (PMS) activation on the surface of catalyst is conducive to further enhancing the pollutant-removing effect. Herein, an N, O co-doped carbon-encapsulated tricobalt tetraoxide (Co3O4@N,O–C) with double active sites is prepared by a one-step laser carbonization method. The optimized Co3O4@N,O–C shows excellent tetracycline (TC) removal ability, in which the k value reaches 0.608 ​min−1. On the surface of Co3O4@N,O–C, TC is adsorbed to the N site, and PMS is activated at the O site. Building double active sites on the catalyst surface not only avoids competition for the active site, but also confines the pollutant molecules to the surface of the catalyst, thus shortening the migration distance between reactive oxygen species (ROS) and the pollutant and boosting the removal efficiency of pollutants. In addition, the Co3O4@N,O–C/PMS system exhibits both good resistance to environmental interference and cyclic stability. Finally, a practical continuous flow reactor based on Co3O4@N,O–C catalyst is built, which shows a stable and efficient TC degradation performance.

Sn-based precursors dependence for electrocatalytic degradation of organic pollutants on Ti/SnO2-Sb electrode

The utilization of SnO2-based coated electrodes prepared through thermal decomposition process for degrading organic pollutants is a prominent topic in the field of wastewater treatment. However, the impact of precursor salts on the structure and catalytic degradation activity of Sn oxide coatings still lacks research. This study examined the procedures for synthesizing SnO2 coatings by high-temperature oxidation of two common Sn chlorides with different valences. Through systematic characterization, it was revealed that the high boiling point of SnCl2 makes it less volatile during the high-temperature oxidation stage, allowing for maximum retention of Sn source on the substrate, thereby forming a dense and stable oxide coating structure (Ti/SnO2-Sb(II)). On the other hand, the low boiling point of SnCl4 makes it easily volatile during heating, resulting in a thin and loose structure coating (Ti/SnO2-Sb(IV)). Due to these factors that the electrical conductivity of Ti/SnO2-Sb(II) is significantly superior to Ti/SnO2-Sb(IV). Moreover, at 20 mA·cm−2, Ti/SnO2-Sb(II) can achieve almost complete decolorization of methylene Blue (MB) in just 40 minutes, while achieving the same decolorization rate with Ti/SnO2-Sb(IV) requires over 90 minutes. Furthermore, stability tests demonstrated that after 5 cycles of reaction, Ti/SnO2-Sb(II) showed no significant decrease in decolorization rate of MB, whereas Ti/SnO2-Sb(IV) exhibited a decline in decolorization performance towards MB starting from the 2nd cycle. This study revealed the crucial role of precursor salt boiling points in the formation of stable SnO2-based coated electrodes, providing a theoretical basis for the development of structurally stable and highly catalytic oxidation active coating electrodes.

Hexagonal Cu2O-Pt alloyed nano-lilies mediated Fenton catalysis for recyclable degradation of organic dye

This paper presents the synthesis of hexagonal lily-like cuprous oxide‑platinum compound nanolilies (HCu2O-Pt NLs) and confirms their successful preparation using various characterization methods. These nano-enzymes possess remarkable photothermal ability, as irradiation under 808 nm near-infrared (NIR) laser causes a rapid temperature increase to about 50 °C. Furthermore, HCu2O-Pt NLs exhibited significantly enhanced Fenton catalytic activity for organic dye pollutant degradation compared to conventional photothermal catalysts, as demonstrated by Rhodamine B (RhB) degradation experiments. Additionally, HCu2O-Pt NLs demonstrated good photothermal stability, reusability, and non-toxicity to the environment, thereby highlighting their potential application in wastewater treatment.

Enhanced catalytic degradation of organic dye by Sn1-xLaxO2 nanoparticles under UV light for wastewater treatment

Effectively eliminating dyes and heavy metals from wastewater, without secondary contamination and with easy recovery, is a significant challenge. To address this, SnO2-based photocatalysts were fabricated using a straightforward sol–gel method, aiming to achieve high-value reutilization and environmental protection. Utilizing XRD, FTIR, and HRTEM, the investigation has conclusively confirmed the emergence of nanoparticles (NPs) through rigorous analysis and observation techniques. Raman, XPS, and PL spectroscopy probed electronic, optical properties, and lattice defects, offering comprehensive insights into material characteristics. Specific BET surface areas were observed to be 17.72 and 39.64 m2/g for 0 % and 5 % La samples. The introduction of dopant La to the SnO2 lattice resulted in enhanced optical properties, demonstrated by a significant red shift. La-SnO2 nanoparticles demonstrated remarkable catalytic efficacy, degrading 94 % of RB dye solution under 60 min of UV light exposure. Even after four cycles, the catalytic degradation activity remained high at 87 %, showcasing excellent structural stability. Enhanced adsorption capacity and effective separation of electron-hole pairs under light contribute to this improvement. Moreover, the study delved into defect-based room temperature ferromagnetism (RTFM) by examining the formation of a novel network, such as La3+-O-Sn4+. The results highlight the potential of these composites doped photocatalysts as effective materials for degrading harmful organic pollutants in wastewater treatment and for their application in spintronic devices. The present study aims to characterize the structural, magnetic, and optical attributes of La-doped SnO2 nanoparticles.

The inherent nature of N/P heteroatoms in Sargassum fusiforme seaweed biochar enhanced the nonradical activation of peroxymonosulfate for acetaminophen degradation in aquatic environments

This study investigated the catalytic activity of biochar materials derived from algal biomass Sargassum fusiforme (S. fusiforme) for groundwater remediation. A facile single-step pyrolysis process was used to prepare S. fusiforme biochar (SFBCX), where x denotes pyrolysis temperatures (600 °C-900 °C). The surface characterization revealed that SFBC800 possesses intrinsic N and P heteroatoms. The optimum experimental condition for acetaminophen (AAP) degradation (>98.70%) was achieved in 60 min using 1.0 mM peroxymonosulfate (PMS), 100 mg L−1 SFBC800, and pH 5.8 (unadjusted). Moreover, the degradation rate constant (k) was evaluated by the pseudo-first-order kinetic model. The maximum degradation (>98.70%) of AAP was achieved within 60 min of oxidation. Subsequently, the k value was calculated to be 6.7 × 10−2 min−1. The scavenger tests showed that radical and nonradical processes are involved in the SFBC800/PMS system. Moreover, the formation of reactive oxygen species (ROS) in the SFBC800/PMS system was confirmed using electron spin resonance (ESR) spectroscopy. Intriguingly, both radical (O2•−, •OH, and SO4•−) and nonradical (1O2) ROS were formed in the SFBC800/PMS system. In addition, electrochemical studies were conducted to verify the electron transfer process of the nonradical mechanism in the SFBC800/PMS system. The scavenger and electron spin resonance (ESR) spectroscopy showed that singlet oxygen (1O2) is the predominant component in AAP degradation. Under optimal condition, the SFBC800/PMS system reached ∼81% mineralization of AAP within 5 min and continued to ∼85% achieved over 60 min of oxidation. Coexisting ions and different aqueous matrices were investigated to examine the feasibility of the catalyst system, and the SFBC800/PMS system was found to be effective in the remediation of AAP-contaminated groundwater, river water, and effluent water obtained from wastewater treatment plants. Moreover, the SFBC800-activated PMS system demonstrated reusability. Our findings indicate that the SFBC800 catalyst has excellent catalytic activity for AAP degradation in aquatic environments.

Acidic ionic liquid-based liposome for efficient catalytic degradation of azo dyes

Amphiphilic ionic liquids (ILs) with an imidazole head and two undecene tails (abbreviated as [MimV11, V11]Br) were synthesized through alkylation reaction. They were utilized as lipoid monomers for constructing an isotropic catalytic degradation platform of azo dyes. The spherical structure of this IL-based liposome was reinforced by cross-linking polymerization of the olefin tails. The imidazole groups served as anchor points for attaching catalytic heteropolyanions (such as [PW12O40]3-, [PMo12O40]3-) to the liposomal vehicle. Furthermore, the arrangement of these linkers on the liposome surface facilitated the trapping and enrichment of the catalytic species. Consequently, a series of isotropic catalysts decorated with heteropolyanions (poly[MimA11, A11][heteropolyanions]) were prepared through anion exchange, where sufficiently exposed heteropolyanions maximized the catalytic degradation activity. The morphology, structure, and properties of the catalysts were confirmed using SEM, TEM, FTIR, XPS, UV–vis, and GC–MS. Experimental results found that poly[MimA11, A11][PW12O40] was the optimal catalyst, achieving a removal efficiency of 97.2% for methyl orange (MO) within 3 h. The intermediates involved in the reaction were analyzed to propose the degradation pathway of MO. Moreover, this kind of solid catalyst could be recovered by centrifugation, and its degradation efficiency remained above 91% even after five cycles. This research provides valuable insights for expanding the applications of IL-functionalized materials.

La doping of CoFe Prussian blue analogs for improved catalytic activity toward norfloxacin degradation

Prussian blue analogs (PBAs) are promising catalysts in heterogeneous oxidation processes. The catalytic activity of PBAs relies on exposed crystal facets and accessible active sites on the PBA framework. Employing a heteroatom doping strategy using a rare earth element (La), we regulated the crystal structure and optimized the catalytic activity of CoFe PBA for peroxymonosulfate (PMS)-driven degradation of the antibiotic norfloxacin (NOR). The La atoms were mainly doped in the interstitial sites of the CoFe PBA cubic lattices, without affecting the electron distributions of Co and Fe metals or the face-centered cubic crystal phase of the coordination skeleton. La doping dominated the (111) and (100) as the main exposed facets of CoFeLa PBA, increasing the affinity of CoFeLa PBAs for PMS adsorption due to the higher surface energy of the two facets. Consequently, the activation energy considerably declined from 77.57 kJ/mol in CoFe PBA to 51.66 kJ/mol in CoFeLa PBA and the catalytic activity for PMS-driven NOR degradation was largely improved, which can reach 76.4 % removal of NOR within 15 min, with an increased initial rate constant k of 0.095 min−1. 1O2 was proven as the main reactive specie responsible for NOR degradation in the PMS/CoFeLa system, and O2·− and SO4·− were verified as the important intermediates to generate 1O2. Thus, La doping can effectively enhance the catalytic performance of PBA-based catalysts for organic pollutant removal.

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.

Solution Blow Spinning Ultrafine Fiber Sponge-Loaded MOF-808 for Effective Adsorption and Degradation of Mustard Gas.

Functional materials that can quickly absorb and degrade mustard gas are essential for chemical warfare emergency response kits. In this study, a fiber membrane with excellent adsorption and catalytic degradation activity was developed by solution blow spinning polystyrene (PS)/polyurethane (PU) and hydrothermal in situ growth of a zirconium-based MOF (MOF-808). The mechanical properties of the PS/PU fibers were improved by adding a trimethylolpropane tris (2-methyl-1-aziridine propionate) (TTMA) cross-linking agent. Moreover, the C═O bonds in TTMA provided abundant growth sites for MOF-808 in the hydrothermal process, thereby greatly increasing the loading capacity. The fiber surface was completely covered with the MOF-808 particles within 24 h. The PS/PU/TTMA/MOF-808 fiber membrane was used for the catalytic degradation of 2-chloroethyl ethyl sulfide (CEES). The degradation efficiency reached 97.7% after 72 h, indicating its great application potential in emergency wiping cloths for mustard gas adsorption and degradation.

Monodispersed ZIF-67 in situ nucleated on CoAl-LDH nanosheets for efficient carbamazepine degradation via activation of peroxymonosulfate

Abundant exposed ligand-unsaturated sites of Co have been found to enhance the catalytic oxidation property of ZIF-67 material for peroxymonosulfate (PMS) catalysis. Nevertheless, serious stacking of ZIF-67 still poses a challenge to its application. Herein, we employed a specific in situ growth strategy to establish an LDHNS@ZIF-67 composite based on morphology modulation and performance optimization for carbamazepine (CBZ) degradation. ZIF-67 crystals were successfully grown in situ via nucleating on the CoAl-LDH nanosheets (LDHNSs) substrate surface, which facilitated the crystals’ dispersion. LDHNS@ZIF-67 (0.1 M) was optimized to display outstanding PMS catalytic activity for CBZ degradation, with almost 100% degradation in 5 min (PMS dose, 0.2 mM, catalyst dose, 25 mg/L, and CBZ concentration, 5 ppm). Quenching and electron paramagnetic resonance (EPR) tests confirmed that both radical substances (SO4•-) and nonradical substances (1O2) dominated the reaction system. As the active site, Co(II) ions on the LDHNS@ZIF-67 (0.1 M) surface effectively promoted active substance formation. The intermediate degradation products and pathways for CBZ were investigated. Toxicity assessment for CBZ and its intermediates was conducted. This work will broaden the application of ZIF-67 materials in advanced oxidation process design based on persulfate.

Nitrogen-doped carbon aerogel supported SnO2 anode for electrocatalytic degradation of phenol: Enhanced generation of free radicals

To obtain a high-efficiency and low-cost electrocatalytic anode for environmental pollutant degradation, a nitrogen doped graphene aerogel supported tin oxide (SnO2-NGA) composite catalyst was prepared and SnO2-NGA/Ti anode was fabricated. The influence of nitrogen doping content on electrocatalytic activity of the catalysts was investigated. The effects of current density and initial solution pH on degradation efficiency were studied. The SnO2-N3.0GA/Ti anode shows good catalytic activity for phenol degradation. The conversion of phenol and COD removal by SnO2-N3.0GA/Ti reached 83.6% and 61.2% within 4 h when applied current density was 5.00 mA/cm2 and initial pH was 3.0. The SnO2-N3.0GA/Ti electrode has higher specific surface area, and lower charge transfer resistance. The nitrogen atoms doping increased the content of pyridinic N species, which is beneficial for providing more in-situ catalytic active sites and enhancing the production of reactive oxygen species, especially hydroxyl radical (•OH). This work provides a novel strategy for synthesis of electrocatalytic anode with enhanced activity for degradation of refractory organic pollutants in water.

Biogenic derived cobalt nanoparticles using Morus alba and their potent antibacterial and catalytic degradation activity

Biogenic derived cobalt nanoparticles using Morus alba and their potent antibacterial and catalytic degradation activity

Deep Oxidation of Chlorinated VOCs by Efficient Catalytic Peroxide Activation over Nanoconfined Co@NCNT Catalysts.

The catalytic removal of chlorinated VOCs (CVOCs) in gas-solid reactions usually suffers from chlorine-containing byproduct formation and catalyst deactivation. AOP wet scrubber has recently attracted ever-increasing interest in VOC treatment due to its advantages of high efficiency and no gaseous byproduct emission. Herein, the low-valence Co nanoparticles (NPs) confined in a N-doped carbon nanotube (Co@NCNT) were studied to activate peroxymonosulfate (PMS) for efficient CVOC removal in a wet scrubber. Co@NCNT exhibited unprecedented catalytic activity, recyclability, and low Co ion leakage (0.19 mg L-1) for chlorobenzene degradation in a very wide pH range (3-11). The chlorobenzene removal efficiency was kept stable above 90% over Co@NCNT, much higher than that of nonconfined Co@NCNS (45%). The low-valence Co NPs achieved a continuous electron redox cycling (Co0/Co2+ → Co3+ → Co0/Co2+) and greatly promoted the O-O bond dissociation of PMS with the least energy (0.83 eV) inside the channel of Co@NCNT to form abundant HO• and SO4•-. Thus, the deep oxidation of chlorobenzene was achieved without any biphenyl byproducts from the coupling reaction. This study provided a new avenue for designing novel nanoconfined catalysts with outstanding activity, paving the way for the deep oxidation of CVOC waste gas via AOP wet scrubber.

A facile green synthesis of Ag@MnO2 nanoparticles using Martynia annua plant extract and their biological activity and catalytic reduction of dye

The Ag@MnO2 NPs were characterized by UV, FTIR, HRTEM, SAED, and EDX analysis. UV analysis revealed the characteristic wavelength absorption maxima at 425 nm, which confirmed the synthesis of Ag@MnO2 NPs. Martynia annua plant extract presented phytochemical compounds that act as reducing and capping agents in the synthesis of Ag@MnO2 NPs, as confirmed by FT-IR analysis. HRTEM analysis to determine the Ag@MnO2 NPs morphology images showed the spherical shape of NPs with sizes from 1 to 8 nm. The crystalline nature of Ag@MnO2 NPs was identified using SAED and EDX analysis revealed the composition of these synthesized NPs. In-vitro antioxidant activities of Ag@MnO2 NPs were evaluated using a DPPH assay for the significant radical scavenging ability of these NPs. Our findings revealed that M.annua plant-mediated Ag@MnO2 NPs have been highly active against both bacterial and fungal strains. The BSA and EA methods for inhibition of albumin denaturation were investigated for their anti-inflammatory activity. The Ag@MnO2 NPs showed superior activity as anti-inflammatory agents, reduced the viability of the human lung cancer cell line A549 up to 9.92 % at a concentration of 500 µg/ml, and exhibited a good cytotoxic effect. In the presence of NaBH4, the Ag@MnO2 NPs showed excellent catalytic degradation activity against Fuchsin basic dye.

MOFs-derived Cu/Carbon membrane as bi-functional catalyst: Improving catalytic activity in detection and degradation of PFOA via regulation of reactive Cu species

Developing bi-functional materials to simultaneously detect and degrade persistent pollutant perfluorooctanoic acid (PFOA) is of significant importance for environmental and human health. In this study, a copper-based mimic enzyme colorimetric detecting sensor coupling with solar photo-electro-Fenton degradation (SPEF) system was built based on Cu/carbon nanofiber (CNF-Cu/C) membrane. Self-supporting flexible CNF-Cu/C membrane was successfully prepared by solvothermal method with further secondary seed growth and in-situ thermal reduction. Based on calcination temperature regulation, the obtained CNF-Cu/C membrane derived from MOFs/polyacrylonitrile (HKUST/PAN) membrane was characterized by 3D carbon fiber network dispersed with porous carbon skeleton embedded copper species, which exhibited good dispersibility, cycling stability and excellent electrical conductivity. With excellent peroxidase-like activity, CNF-Cu/C can rapidly detect PFOA based on the inhibition of color reaction of tetramethylbenzidine (TMB) with detection limit of 0.133 μM. Furthermore, CNF-Cu/C also exhibited outstanding optical properties and oxygen redox reaction (ORR) activity, and the removal efficiency of PFOA in Cu-SPEF system reached 98.22 % within 180 min under optimal conditions. Based on the results of free radical quenching experiment, EPR experiment and HPLC-MS experiments, the degradation mechanism and degradation path of PFOA by SPEF system were further speculated.

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.

Green synthesis of MnO2 nanoparticles from Psidium guajava leaf extract: Morphological characterization, photocatalytic and DNA/BSA interaction studies

In this work, a simple, efficient and eco-friendly green synthesis of manganese dioxide nanoparticles (MnO2NPs) by Psidium guajava leaf extract was described. Fourier-Transform infrared spectra results revealed that involvement of the plant extract functional groups in the formation of MnO2NPs. The UV–vis absorption spectra of the synthesized MnO2NPs exhibited absorption peaks at 374 nm, which were attributed to the band gap of the MnO2NPs. Crystal phase identification of the MnO2NPs were characterized by X-ray diffraction analysis and the formation of crystalline MnO2NPs have been confirmed. Furthermore, scanning electron microscopy analysis showed that the synthesized MnO2NPs have a spherical in shape. Interestingly, the prepared green synthesized MnO2NPs showed catalytic degradation activity for malachite green dye. Malachite green's photocatalytic degradation was detected spectrophotometrically in the wavelength range of 250–900 nm, and it was discovered to have a photodegradation efficiency of 75.5 % within 90 min when exposed to solar radiation. Green synthesized MnO2NPs are responsible for this higher activity. An interaction between synthesized NPs and biomolecules, including CT-DNA and BSA was also evaluated. The spectrophotometric and Fluoro spectroscopic analyses indicate a gradual reduction in peak intensities and shifts in wavelengths, indicating binding and affinity between the NPs and the biomolecules.

Preparation of a new B-CNTs/PSSF composite catalyst for catalytic wet peroxide oxidation of phenol in structured fixed bed

A new structured catalyst consisting of boron-doped carbon nanotubes growing directly on paper-like stainless steel fibers support (B-CNTs/PSSF) was developed for continuous catalytic wet peroxide oxidation (CWPO) of phenol in a structured fixed bed. Firstly, B-CNTs/PSSF was synthesized by chemical vapor deposition (CVD) with phenyboronic acid as a single precursor and CNTs/PSSF was prepared with camphor for comparison. Secondly, the effects of different deposition temperatures, deposition times, and phenylboronic acid dosages on the morphology and properties of B-CNTs were investigated, respectively. The results verified that under the conditions of deposition temperature of 750 °C, deposition time of 20 min, and phenylboronic acid dosage of 2 g, the B-CNTs/PSSF composite catalyst with uniform growth density, wavy and kinked morphology, abundant oxygen-containing functional groups and defect sites, and boron-doped content of 2.96% was successfully prepared. Then, the performance of B-CNTs/PSSF for continuous CWPO of phenol was evaluated. Catalytic results revealed that the B-CNTs/PSSF showed excellent catalytic activity in phenol degradation within 7 h (phenol conversion reached about 100% and total organic carbon (TOC) conversion was up to 68%). In contrast, the average phenol and TOC conversion of CNTs/PSSF were about 75% and 35%, respectively. It indicated that boron doping endowed CNTs with higher catalytic activity.

High-efficient charge separation in novel Zn0.5Cd0.5S/Bi4V2O11 heterostructure for boosting photocatalytic Cr (VI) reduction and degradation of tetracycline hydrochloride

Photocatalysis is a green and sustainable technology for the efficient removal of harmful pollutants in water, however, due to the coexistence of multiple pollutants in water system, it is a great challenge to develop multi-functional and efficient photocatalytic systems. Herein, a novel bifunctional Zn0.5Cd0.5S/Bi4V2O11 (ZCS/BVO) heterostructrue photocatalyst was designed and prepared by growing Zn0.5Cd0.5S nanospheres on the surfaces of Bi4V2O11 disc-like nanoflowers through a facial in-situ hydrothermal method. The as-prepared ZCS/BVO heterostructure showed much more enhanced bifunctional visible-light catalytic activity for Cr (VI) reduction and TCH degradation compared with pure Zn0.5Cd0.5S and Bi4V2O11. Among ZCS/BVO samples, ZCS/BVO-10 possessed the best Cr (VI) reduction performance of 86.7 % in 60 min, which was 1.38 and 9.96 times of Zn0.5Cd0.5S and Bi4V2O11. Moreover, ZCS/BVO-10 heterostructure also showed excellent TCH degradation ability of 80.3 % in 48 min, about 2.38 and 3.20 times as high as those of Zn0.5Cd0.5S and Bi4V2O11. The synergistic effect between Zn0.5Cd0.5S and Bi4V2O11 and the close contacted ZCS/BVO heterostructure greatly favored TCH degradation and Cr (VI) reduction reactions due to the increased surface area, enhanced light absorption and boosted charge separation. From the cyclic experiment, ZCS/BVO exhibited high stability and reusability. This work undoubtedly provided a multi-functional and effective photocatalyst for treating various pollutants in water bodies.