DRS Analysis Research Articles

Pharmaceutical wastewater treatment using TiO2 nanosheets deposited by cobalt co-catalyst as hybrid photocatalysts: combined experimental study and artificial intelligence modeling

Abstract In this work, we developed a facile method for photocatalytic deposition of cobalt atoms as co-catalyst on TiO2 nanosheets (Co(x)/T) under visible light instead of UV irradiation for the first time. The deposition of cobalt atoms on TNs in the Co(x)/T samples was confirmed by DRS, Raman spectroscopy, photoluminescence, nitrogen physisorption, and TEM analyses. The size of cobalt nanoparticles/cluster dispersed on the TiO2 nanosheets were in the range of 5–20 nm according to TEM results. The PXRD patterns showed that the crystal structure and the anatase phase of TNs were preserved in the Co(x)/T samples after the visible light-assisted deposition process. The Co(x)/T samples showed higher activity compared to pure TiO2 nanosheets for the visible light degradation of tetracycline (TC) as pharmaceutical pollutant due to presence of cobalt co-catalyst. We studied the effect of several parameters on the degradation process and proposed the mechanism of degradation according to quenching experiments results. Due to time-consuming and costly of experimental works, we designed two strong artificial intelligence (AI) models (artificial neural networks (ANN) and neuro-fuzzy inference systems (ANFIS)) to estimate the removal process of TC, and predict the removal percent of TC for new values of inputs before performing experiment. The experimental and computational studies showed that the fabricated photocatalysts are as promising candidates for industrial wastewater treatment to meet environmental regulations and provide a new avenue for practical implications.

Bio-inspired functional photocatalyst: Lipase enzyme functionalized TiO2 with excellent photocatalytic, enzymatic, and antimicrobial performance

Herein, we proposed a novel approach for the improvement of a photocatalytic material via functionalization with biocatalyst for successfully utilization in photocatalytic, enzymatic, and antimicrobial processes. For this, titanium dioxide (TiO2) was first modified using 3-aminopropyltriethoxysilane (APTES) to incorporate silane groups for the effective immobilization of Lipozyme TL 100 L enzyme. The as-synthesized samples were characterized by FT-IR, TGA, BET, SEM, XRD, XPS, UV–vis DRS and PL analyses in order to examine the thermal, structural, textural and optical features. The covalent immobilization yield of lipozyme on the modified TiO2 (TiO2@APTES) was found to be 97.5 % with 2,437.5 U/g of enzyme activity, and the immobilized enzyme (TiO2@LPZM) displayed excellent stability at different pH and temperatures when compared to its free form. The photocatalytic performance of TiO2@LPZM towards degradation of antibiotics significantly enhanced under both UV-A and visible light irradiation. The tetracycline and ciprofloxacin degradation rates of the bio-inspired photocatalyst were found 3.4- and 1.65-times higher than that of raw TiO2, respectively. The enhanced performance was ascribed to the attachment of target antibiotics by enzyme molecules, extended light absorption and reduced recombination rate of charge pairs. In addition, the enzyme immobilization increased the surface adsorbed oxygen species which boosted the photocatalytic reaction. The antimicrobial activity tests of the samples were examined against two types of bacterial species as E. coli and S. aureus and the enhanced antibacterial efficiencies were attributed to the presence of silanol, amino, and hydroxyl groups of modified TiO2. This research highlights the importance of enzyme immobilization on a photocatalytic support with synergistically improved surface features.

A novel adsorptive and photocatalytic system for dye degradation using ZIF-8 derived carbon (ZIF-C)-modified graphene oxide nanosheets

BackgroundAerogels have attracted widespread interest in adsorption and photocatalysis. The effect of single aerogel material cannot meet the demand and we can enhance the adsorption and photocatalysis efficiency via adding other materials such as ZIF-8 and graphene oxide (GO). MethodsWe developed an adsorptive and photocatalytic system of ZIF-GO/CCA using a cellulose-based carbon aerogel (CCA) for the fabrication of GO nanosheets modified with ZIF-8-derived carbon (ZIF-C), followed by pyrolysis. The characteristics were evaluated using SEM, HRTEM, BET, XRD, XPS, UV–vis DRS, ESR, PL, EIS and LC-MS analysis. Significant findingsCCA exhibit hierarchical porosity and conductive network, which provides abundant active sites for dye adsorption and degradation. ZnO and g-C3N4 were formed after the incorporation of ZIF-C into GO to, promote charge separation. In the presence of 1ZIF-GO/CCA and at an initial concentration of 300 mg·L−1 MG, the removal of MG exceeded 96%. The removal capacity reached 1152 mg·g−1 after adsorption-photocatalysis for 120 min. 1ZIF-GO/CCA showed the largest specific surface area (375.059 m2·g−1). GO served as an excellent electron accepter to enable fast electron transfer from the ZIF-C to the conduction band of GO. The narrower bandgap (2.06 eV) and lower resistance during charge transfer promoted the separation of e−/h+ and contributed to the higher photocatalytic activity of ZIF-GO/CCA. Further, ZIF-GO/CCA showed increased recyclability. The plausible photocatalytic mechanism for the 1ZIF-GO/CCA was discussed.

Construction of a novel ZnO/rGO hybrid composite for efficient degradation of CV, Cr (VI) and 2, 4-D under visible light irradiation

The pristine ZnO and ZnO-Graphene hybrid composites at various graphene ratios were synthesized via facile ultrasonic assisted solution approach. The crystal structure is identified by powder XRD technique and disclosed the hexagonal wurtzite structure. The synthesized ZnO exhibited uniform spherical like morphology with low degree of aggregation. The formation of hybrid composite of graphene and ZnO could improve the light absorption ability and separation of photo generated carriers of ZnO, which is confirmed through photoluminescence and UV–Vis DRS analysis. The photo catalytic degradation of Crystal violet, Cr (VI) and 2, 4 D were evaluated under visible light irradiation. The Zn-Graphene hybrid composite exhibited higher photo catalytic activity towards CV dye, Cr (VI) and 2, 4-D, such as high photo degradation efficiency and good stability than bare ZnO. This could be due to the high surface area and synergic effect between the graphene and ZnO p–n junctions. The mechanism of enhanced photo catalytic activity of Zn-Graphene composite discussed in detail.

Comparative Study on Enhanced Photocatalytic Activity of Visible Light-Active Nanostructures for Degradation of Oxytetracycline and COD Removal of Licorice Extraction Plant Wastewater

This study evaluates the effects of carbon, nitrogen, and sulfur dopants on the photocatalytic activity of TiO2 for degradation of oxytetracycline (OTC) and chemical oxygen demand (COD) removal from licorice extraction plant wastewater (LEPW). Three novel visible-light-responsive nanostructures, including L-Histidine-TiO2, L-Methionine-TiO2 and L-Asparagine-TiO2, were successfully synthesized. The results showed that the modification of TiO2 with these three amino acids made the catalyst active in the visible light region and reduced the recombination rate of e−/h+ pairs according to PL analysis. The photodegradation efficiency of L-Histidine (2 wt.%)-TiO2 was 100% and 94% for OTC and COD, respectively. It showed the highest photocatalytic activity under illumination, compared to L-Methionine (1.5 wt.%)-TiO2 and L-Asparagine (2 wt.%)-TiO2. Synthesized composites were characterized with SEM, XRD, FTIR, DRS, and PL analyses. The biological oxygen demand to COD (BOD5/COD) ratio for treated LEPW was determined to be 0.5–0.6, confirming the enhanced biodegradability of the treated effluent. The effect of the independent variables, namely, initial concentration of OTC and COD, catalyst dosage, irradiation time, pH of solution, and light intensity, on the photocatalytic process was evaluated by Response Surface Methodology (RSM), and the optimum value of each independent parameter for maximum degradation of OTC and COD by L-Histidine (2 wt.%)-TiO2 was determined. The radical trapping experiment was performed with various scavengers in order to propose a photocatalytic mechanism, showing that hydroxyl radicals were the main active species. L-Histidine (2 wt.%)-TiO2 showed a stable and reusable structure even after four cycles of COD removal under the following optimal conditions of [COD]: 300 mg/L, [catalyst]: 1 g/L, light intensity: 25 W/cm2 at pH = 4 after 180 min irradiation.

Enhanced photocatalytic activity of TiO2 nanotubes decorated with Ag nanoparticles by simultaneous electrochemical deposition and reduction processes

The photocatalytic activity of the modified TiO2 nanotubes (TNTs) for water purification was studied. Three modification methods including Ag nanoparticles (NPs) decoration (TNT-Ag), electrochemical reduction of the TNTs (TNT-H), and a simultaneous combination of these two methods in one cell (TNT-Ag-H) were investigated. The TEM results showed that the defects formed during the electrochemical reduction, when two methods are combined, act as preferred sites for Ag nucleation, resulting in finer Ag NPs with better distribution. The average size of homogeneous distributed Ag NPs was measured in the range of 3–5 nm. Accordingly, XPS analysis showed an increased amount of Ag NPs on the surface of the modified TNTs in TNT-Ag-H sample. It was also observed that electrochemical reduction was not stable and thus had minor effects on the optical properties of the TNTs. Moreover, the TNT-Ag-H sample showed enhanced SPR and increased absorption in the whole visible light region in DRS analysis. This sample also showed a higher photocatalytic performance in the degradation of two different organic pollutants. The kinetic rate constant after 300 min reached up to 9.12 × 10-3 and 1.39 × 10-3 min−1 for MB degradation under UV and visible irradiation, respectively, which are two times higher than unmodified TNT samples.

Synthesis of Zn doped black TiO2 nanoparticles for degradation of 2, 4, 6 tri-chloro-phenol under visible light

A modified sol-gel method was used for synthesis of zinc doped black TiO2 nanoparticles. The modified sol-gel synthesised catalyst was utilised for degradation of 2, 4, 6 tri-chloro-phenol under visible light irradiation. The catalyst was characterized using XRD, SEM, TEM, BET and DRS analysis. The nanoparticles were crystalline in nature and in anatase phase. The size of zinc doped black TiO2 nanoparticles was 5 nm. The synthesised nanoparticles were mesoporous in nature and the specific surface area was found to be 34.15 m2/g. The band gap energy of zinc black TiO2 nanoparticles was found to be 2.73 eV. The point of zero charge of zinc doped black TiO2 nanoparticles was 6.7. The maximum degradation of 2, 4, 6 tri-chloro-phenol using 2 mol% zinc doped black TiO2 was found to be 95%.

Visible-light-driven super-active Sn and GO single- and Sn/Cu Co-doped nanophotocatalysts for phenol degradation: Thin-film printability, thermal stability, and cytotoxicity assay

Sn- and graphene oxide (GO) single-doped and Sn/Cu co-doped titanium dioxide (TiO2) nanoparticles were synthesized as printed-layer nano-photocatalysts for degradation of phenol under visible-light. The doped TiO2 nanoparticles (Sn-doped-TiO2, Cu/Sn-doped-TiO2, and GO-doped-TiO2) were synthesized via sol–gel method and calcinated at a temperature of 450 °C. X-ray diffraction (XRD), UV–Visible DRS analysis, Raman analyses, and Energy-dispersive X-ray spectroscopy (EDXS) were utilized to evaluate the crystalline structure and photocatalytic activities of doped-TiO2 nanoparticles. Different screen-printing pastes were separately formulated with 26% w/w doped-TiO2 nanoparticles (Paste1-to-Paste3) for printing onto microscope glass slides. Photocatalytic printed film was sustainable filter for unused suspension of nanoparticles in wastewater. The printed pasts were sintered at varying temperatures (100–500 °C), then three-layer printed nanoparticles sintered at 500 °C examined for photocatalysis. Photocatalytic activity of single-layer-printed GO-doped-TiO2 nanoparticles was extraordinary (80% degradation of 10 ppm phenol solution). Hydroquinone, catechol, benzoquinone and acetic acid were observed to be produced at different concentrations over different time intervals as a result of phenol degradation for single-layer-printed GO-doped-TiO2 nanoparticles sintered at 500 °C. Bandgap of GO-doped-TiO2 nanoparticles was 2 eV, meaningfully lower than anatase TiO2 (3.2 eV). The cytotoxicity assay applied for normal and cancer cells demonstrated cytocompatibility besides photodegradability. This novel process is a targeted, clean, cost-effective and on-demand approach, taking a big step toward decontamination of the environmental pollution.

Excellent photocatalysis of Bi2WO6 structured with oxygen vacancies in degradation of tetracycline

Photocatalysis is a green, efficient and clean pollutant degradation technology. In this work, a novel Bi2WO6 photocatalytic material with oxygen vacancies was synthesized by a simple solvothermal method using ethylene glycol and ethanol as solvents. Tetracycline, as typical antibiotic organic pollutant, was selected to evaluate the photocatalytic activity of the prepared photocatalyst. The prepared oxygen-deficient Bi2WO6 material has good photocatalytic activity under visible light irradiation. The results showed that the oxygen-deficient Bi2WO6 was regular microsphere in shape with narrower and more uniform pore size distribution than Bi2WO6. Moreover, when visible light irradiation was lasted for 180 min, the degradation rate of tetracycline reached 79.68%, showing a higher degradation rate compared with that of Bi2WO6. Furthermore, after four cycles, the degradation rate of tetracycline could still reach 68.64%. This was due to the oxygen vacancies significantly enhanced the photocatalytic activity of Bi2WO6. In addition, as shown by the UV–Vis DRS analysis, the presence of oxygen vacancies enhances the utilization of visible light by Bi2WO6, and reduces the band gap of Bi2WO6. This study will provide an innovative idea for the construction of oxygen-deficient photocatalysts for water treatment.

Microwave absorbing characteristics of porphyrin derivates: a loop of conjugated structure.

Microwave absorbing architectures have gained a great deal of attention due to their widespread application in diverse fields, especially in refining electromagnetic pollution. The aim of this study is to investigate the metamaterial characteristics of porphyrin derivatives as conjugated rings in the microwave region and evaluate the influence of electron-withdrawing and donating groups on microwave attenuating performance. Initially, an innovative microwave curing procedure was applied to synthesize the derivates; following that, the phenyl, aniline, and nitrophenyl-coupled structures were identified by XRD, FTIR, FESEM, and DRS analyses. The optical features illustrated that the characteristic band gap of the conjugated loops is obtained and that the optical performance can be manipulated by coupling the functional groups. Eventually, the achieved results demonstrated that the best microwave absorbing performance is related to aniline-coupled porphyrin with a maximum reflection loss (RL) value of -104.93 dB at 10.09 GHz with 2.80 mm in thickness attaining an efficient bandwidth (EB) (RL ≤ 10 dB) higher than the X-band. Noticeably, polyethylene (PE) was applied as an absorbing matrix presenting a meaningful idea for the development of practical microwave absorbers as a new generation of electromagnetic refining and stealth materials. The presented research provides precious inspiration to tailor novel microwave absorbing materials with metamaterial capability to promote their microwave absorbing performance.

Utilizing ferrocene for doping iron into graphitic carbon nitride (FeIII/g-C3N4): an internal dual photocatalyst for tandem oxidation/cyclization of toluene to benzimidazoles under visible light conditions.

Recently, doping metals into graphitic carbon nitride (g-C3N4) is considered for environmental applications and organic reactions. In this study, we used ferrocene as a source of Fe3+ to dope iron onto g-C3N4. The scaffold of the internal electric field is presented as an impressive strategy to increase photocatalytic activities. Fe3+ was doped onto graphitic carbon nitride (FeIII/g-C3N4) by the calcination method, which was well characterized by FT-IR, Raman, XRF, XRD, XPS, UV-visible DRS, photo-luminescence (PL), photocurrent, SEM, HR-TEM, EDX, BET, EIS, and cyclic voltammetry analyses. The synthesis of benzimidazole derivatives as pharmaceutically active compounds was introduced by using a suitable method under mild reaction conditions without using a base, oxidant, and other reagents or additives. The modification by using iron had a considerable effect on the optical and electronic characteristics in contrast to g-C3N4. The nanocomposite FeIII/g-C3N4 could be employed as a multifunctional photocatalyst to perform the tandem process, oxidation of toluene, and then cyclization with o-phenylenediamines to prepare benzimidazoles under visible light conditions. The existence of the dynamic equilibrium of Fe3+/Fe2+ helped in significantly improving the activity. By changing the reaction conditions and different control experiments as well as Mott-Schottky plot analysis, the superoxide ion (O2˙-) can be obtained as the reactive species in this reaction. The photocatalytic activity of FeIII/g-C3N4 for this one-pot reaction is also investigated in detail.

Viable production of hydrogen and methane from polluted water using eco-friendly plasmonic Pd-TiO2 nanocomposites.

Solar-to-fuel conversion is a novel clean energy approach that has gained the interest of many researchers. Solar-driven photocatalysts have become essential to providing valuable fuel gases such as methane and hydrogen. Solar energy has emerged as a renewable, abundant energy source that can efficiently drive photochemical reactions through plasmonic photocatalysis. As a capping agent, orange peel extract was used in this study in a microwave-assisted green method to incorporate titanium dioxide with distinct amounts (3, 5, and 7 wt%) from Pd-plasmonic nanoparticles (2-5 nm). The leading role for plasmonic nanoparticles made from Pd-metal is enhancing the photocatalyst's ability to capture visible light, improving its performance. X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Brunauer, Emmett, and Teller (BET) surface area analysis, and UV-vis DRS analyses have investigated the obtained plasmonic photocatalysts' crystallographic, morphological, and optical characteristics. The UV-vis absorption spectra demonstrated the visible light absorption capacity attributed to the localized surface plasmonic resonance (LSPR) behavior of the newly formed nanoplasmonic photocatalysts. The generated Pd-TiO2 nanomaterials' photocatalytic activity has been examined and evaluated for combustible gas production, including the formation of CH4 and H2 from the photocatalytic degradation of Reactive Yellow 15 (RY) during a deoxygenated photoreaction in a homemade solar photobiogas reactor.

Precipitation Method and Sonication Technique for Advanced Superiority of Nanospherical BiFe2O3 and its Multi-Applications

In this work, a modified BiFe2O3 nanomaterial was prepared using a combination of co-precipitation and sonication methods. High-resolution scanning electron microscopy (HRSEM) results revealed a nanospherical shaped structure. The energy dispersive X-ray analysis (EDX) analysis confirmed that Bi, Fe and O are present in the BiFe2O3 nanomaterial. The photoluminescence analysis also confirmed the presence of bismuth in the BiFe2O3 nanomaterial. The recombination of electron-hole pairs in Fe2O3 transpires when the electrons and holes were transferred between Bi and Fe2O3 nanomaterials. The UV-Vis DRS analysis revealed that the nanomaterial decrease band gap energy and increased the photoenergy. The modified BiFe2O3 was successfully used as multi-functional materials, such as a photocatalytic material for the photodegradation of Rhodamine B and Rhodamine 6G dyes, antibacterial agent and as improved dye sensitized solar cells (DSSCS).

Efficient photodegradation of methyl orange dye using electrogenerated copper-zinc oxide hybrid

A photoactive Cu-doped ZnO (Cu/ZnO) hybrid was synthesized via a simple electro-generation procedure. The resultant catalyst was then subjected to UV–vis DRS and BET analysis for band gap and porosity properties studies. The photocatalytic efficiency of the Cu/ZnO hybrid was then evaluated via discoloration reaction of dye pollutant, methyl orange (MO) under visible light irradiation. To study the effect of Cu loadings on the hybrid catalyst performance, a series of catalysts with different Cu wt.% were synthesized and tested for MO degradation. As result, ZnO doped with 5 wt% Cu was found as the most active catalyst with 100 % MO removal followed by 3 wt% Cu/ZnO (94 %), 7 wt% Cu/ZnO (71 %) and 10 wt% Cu/ZnO (40 %). Whereas, in the presence of pure ZnO, only 23 % MO was managed to be degraded, remarking its low catalytic reactivity compared to Cu/ZnO hybrids, especially 5 wt% Cu/ZnO. This might be due to the increase in surface area and lower band gap of 5 wt% Cu/ZnO (3.11 eV) compared to ZnO (3.20 eV) as analyzed by BET and UV–vis DRS respectively. Meanwhile, the optimum reaction conditions were found to be pH 3, 10 mg/L initial dye concentration, and 0.38 g/L of 5 wt% Cu/ZnO. Conclusively, the electrogenerated Cu/ZnO catalyst was highly capable of degrading methyl orange dye pollutants and therefore has a high potential for future wastewater treatment application.

Electrochemical Performance of Tellurium Oxide on TiO2/Ti Array for Photoelectrocatalytic Chemical Oxygen Demand Sensor Applications

The experiments were carried out using Te-TiO2/Ti as working electrodes, prepared by the simple anodization technique and dip coating method, on Ti substrates (TiO2/Ti). The measurements were performed in an electrochemical cell using a three-electrode system, with Te-TiO2/Ti as the working electrode, Ag/AgCl as the reference electrode and pt as the auxiliary electrode. A flow system for determining the profile and photocurrent response of reactive orange 84 was developed using Linear Sweep Voltammetry (LSV) and Multi-Pulse Amperometry (MPA). The physicochemical properties of Te-TiO2/Ti electrodes have been studied using UV–vis DRS analysis techniques and compared with un-doped TiO2/Ti electrodes. The UV–vis DRS showed that the TiO2/Ti doped Te functionally decreases bandgap to 3.0 eV. The results showed that the photocurrent of reactive orange 84 was observed in the concentration range (1-5 μM), with a linear response between concentration and charge.

A Novel Approach for Generation of Oxygen Vacancies in Trirutile MnSb2O6 and Their Impact on Photocatalytic Degradation of MO Dye

AbstractVisible light‐driven photocatalysis has gained much attention due to its light‐harnessing characteristics and is extensively used in wastewater remediation. This paper presents a novel oxygen‐deficient manganese antimonate, MnSb2O6‐x, with a trirutile structure as an effective visible‐light‐driven photocatalyst for dye degradation. The synthesized samples were subjected to XRD, UV‐Vis DRS, SEM‐EDS, Raman, XPS, and PL analyses to study their physic chemical properties. The influence of sequential or single heating during the preparation method on the generation of oxygen vacancies is evaluated using UV‐Vis DRS, XPS, ESR, and Raman techniques. The oxygen‐deficient MnSb2O6 could achieve up to 85 % of MO degradation in 180 min under visible light irradiation, and its reusability up to six cycles was also investigated. In addition, the mechanism of dye degradation was supported with a scavenger test, and the degradation activities are correlated to the electron‐hole pair separation as convinced from the PL spectra. The simple and unique method of oxygen vacancy generation can inspire the development of antimonates with oxygen deficiencies, which have significant scope of application in environmental and energy conservation.

Enhanced photocatalytic degradation of sulfamethazine by g-C3N4/Cu, N-TiO2 composites under simulated sunlight irradiation

The g-C3N4/Cu, N-TiO2 heterojunction photocatalysts were prepared employing co-precipitation and calcination methods in this work. The as-prepared photocatalysts were characterized using several analytical testing methods such as XRD, SEM, EDS, XPS, UV–vis DRS, and photoluminescence spectra. SEM and EDS analysis confirmed the formation of heterojunction between Cu, N-TiO2 and g-C3N4 and uniform distribution of C, N, Ti, and O elements in the CN/Cu, N-TiO2-1 composite photocatalyst. UV–vis DRS analysis displayed that N and Cu co-doping can reduce the band gap of the involved catalysts, leading to improvement of light absorption. Photoluminescence spectra analysis showed that combining Cu, N-TiO2 and g-C3N4 can improve photogenerated charges separation effectively, demonstrating the formation of g-C3N4/Cu, N-TiO2 heterojunction in CN/Cu, N-TiO2-1 composite photocatalyst. The photocatalytic performance of the synthesized catalysts was evaluated under simulated sunlight irradiation via sulfamethazine (SMZ) degradation experiments. The results displayed that g-C3N4/Cu, N-TiO2-1 heterojunction photocatalyst (with a mass ratio of 1:1 of Cu, N-TiO2 to dicyandiamide) showed the optimum performance with a transformation rate of SMZ of 95.80 % under 240 min irradiation. The plausible photocatalytic mechanism involving g-C3N4/Cu, N-TiO2-1 was proposed according to the trapping experiments of active species, which confirmed that O2•− radicals were the primary active component in photocatalytic degradation of SMZ and h+ and •OH also exhibited significant roles. Furthermore, the main pathways for SMZ degradation were proposed by identifying the involved degradation intermediates. The present research indicates that g-C3N4/Cu, N-TiO2 heterojunction photocatalyst is encouraging for the elimination of sulfonamide antibiotics from actual wastewater.

Improved catalytic performance of ZnO via coupling with CoFe2O4 and carbon nanotubes: A new, photocatalysis-mediated peroxymonosulfate activation system, applied towards Cefixime degradation

In this study, a ternary ZnO@spinel cobalt ferrite@carbon nanotube magnetic photocatalyst (ZSCF@CNT) was successfully synthesized and used to activate peroxymonosulfate (PMS) for Cefixime (CFX) antibiotic degradation under UVC irradiation. The morphology, optical, structural, and physicochemical properties of ZSCF@CNT were characterized and analyzed by XPS, XRD, FESEM-EDX, TEM, BET, VSM, UV–vis DRS and PL analysis. The results indicated that the ternary ZSCF@CNT photocatalyst exhibited superior catalytic activity on CFX elimination than that of individual components and binary composite catalysts, in which CFX with was rapidly removed under UVC irradiation and PMS. The effect of operational parameters including initial PMS, catalyst, and CFX concentrations and solution pH on the catalytic activity was investigated in detail; the optimal conditions were: pH: 7.0, catalyst: 0.3 g/L, PMS: 3.0 mM, leading to total CFX (10 mg/L) elimination in ∼20 min. Based on the radical scavenger tests, various radicals and non-radical species including sulfate, hydroxyl and superoxide radicals, singlet oxygen and electrons were involved in the ZSCF@CNT/PMS/UVC system. The high surface area, reduced agglomeration formation and excellent separation of photogenerated electron-hole pairs embodied in ZSCF@CNT photocatalyst conferred its superior catalytic activity and stability. The results from the tests in real water matrices revealed that ZSCF@CNT could be a promising photocatalyst to activate PMS for actual aqueous matrices’ treatment.

A simple nanocomposite photocatalyst HT-rGO/TiO2 for deoxynivalenol degradation in liquid food

A simple nanocomposite photocatalyst HT-rGO/TiO2 for deoxynivalenol (DON) degradation was synthesized by hydrothermal method to maintain the quality of cereal grains and byproducts. The characterization of HT-rGO/TiO2 was analyzed by XRD, FTIR, Raman spectroscopy, and XPS. Moreover, according to UV–vis DRS analysis, HT-rGO/TiO2 had a smaller band gap, indicating a wider response range to light and a higher utilized rate of quantum photons. Additionally, the results of LC-MS showed that the hydroxyl group at the C3 position, and the unsaturated bond between C9 and C10, and the epoxy group at C12 and C13 positions of DON molecule were destroyed step by step by photocatalytic degradation. These groups have active effects on the DON toxicity, which means it is successful to degrade DON in liquid-food by HT-rGO/TiO2 photocatalyst.

Macroporous flowerlike Bi2O2CO3-CuBi2O4 nanoheterojunction photocatalyst for high concentrated malachite green degradation: Influence of nanocomposite composition and sonication approach

In this work, the novel CuBi2O4 surface-sensitized bismuth subcarbonate as flowerlike sun-light dual-nanoheterojuncted photocatalysts, in different weight ratios of CuBi2O4 to Bi2O2CO3, were prepared via the facile hydrothermal technique with the assistance of ultrasonic waves. Structural characterization, surface morphology, and optical properties of nanophotocatalysts were investigated with XRD, FESEM, TEM, BET-BJH, DRS, and PL analyses. The results represented the highest degradation percentage (91.6 %) for 200 mg/L malachite green over Bi2O2CO3-CuBi2O4 (1:1)-SH nanocomposite under 180 min sunlight irradiation due to two light absorption edges and separation of the charge carriers promoted owing to the heterojunction formation and the specific flowerlike morphology. It has a meso/macroporous structure with 12.4 m2/g surface area, Vmeso= 0.085 cm3/g and Vmacro = 0.039 cm3/g in which facilitates the intra-diffusion and adsorption of malachite green macromolecules Furthermore, the selected nanophotocatalyst stability, reaction mechanism, and kinetic evaluation were examined.