Search

In this study, the porous graphite phase carbon nitride photocatalyst (P-g-C3N4) is prepared by the CaCO3 template method, and then P-g-C3N4/T-polyethylene terephthalate (T-PET) catalytic fibre is prepared by the padding method. P-g-C3N4 can provide more active sites than g-C3N4 as proved by the Brunauer–Emmett–Teller and the UV–Visible diffuse reflectance test. P-g-C3N4 powder catalyst successfully supports PET fibre as proved by scanning electron microscope, Fourier infrared spectroscopy and X-ray diffraction spectroscopy. The photocatalytic performance of P-g-C3N4/T-PET catalytic fibre is tested by constructing a single hexavalent chromium or hexavalent chromium/organic pollutant binary pollution system. The potential application value of P-g-C3N4/T-PET catalytic fibre is further explored by simulating the complex actual water environment. After five recycles, P-g-C3N4/T-PET catalytic fibre shows good catalytic performance. The mechanism of P-g-C3N4/PET photocatalytic degradation of organic pollutants is proposed through the capture agent experiment and electron paramagnetic resonance spectroscopy. Among them, •O2− is the most important active species of P-g-C3N4 catalytic fibre, which is used for the oxidation of organic pollutants. At the same time, photoelectrons generated by the catalytic fibre are used to reduce hexavalent chromium. The efficiency of P-g-C3N4 to remove pollutants is improved by using PET fibre as a carrier, which not only solves the problem of difficult recovery of powder catalysts but also provides more active sites. [ABSTRACT FROM AUTHOR]

Utilising the solution combustion technique, nanocrystalline photocatalysts that included both pristine TiO2 and doped TiO2 with various La (III) dopant percentages (1, 3, 5, and 7 mol%) were created. Different methods, including thermal analysis, high resolution-transmission electron microscopy (HR-TEM), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT-IR), and field-emission scanning electron microscopy (FE-SEM), were used to investigate the prepared nanostructures. The XRD results indicated the anatase form and the crystalline nature of the products (pristine and doped TiO2) in the size range of a crystallite (5–16.5) nm. The photocatalytic assessment of the prepared nano-photocatalysts was carried out by crystal violet (CV) decolourisation under ultraviolet (UV) light. The findings revealed that 3% La-TiO2 showed the highest degradation efficiency (95.98%) in 70 min with a pseudo-first-rate constant of k = 4.73 × 10−2 min−1, compared to pristine TiO2 and the other TiO2 nanostructures with various La (III) dopant ratios. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the performance of the Pd@TMU-16 to act as a photocatalyst in degrading the Acid Red 88 (AR88) dye from an aqueous solution, via photocatalysis process, using UV irradiation. The synthesis of this catalyst was performed under conditions of thermal solvent and its characteristic parameters were confirmed using the XRD, Band gap, SEM, BET, pHPCZ, and FTIR methodologies. The influence exerted by the operative parameters on the AR88 degradation, which included the pH, reaction time, radiation intensity, catalyst mass, and initial dye concentration was examined. At the optimum condition of photocatalysis and utilising only 0.75 g of Pd@TMU-16, total degradation of 10 mg/L dye concentration was performed. From the kinetic studies, the dye degradation indicated that it was similar to the pseudo-first-order model, and the dye degradation mechanism had taken place through the hydroxyl (•OH) and superoxide radicals (•O⁻₂). The adsorbent reusability was also studied, and from the results it was evident that the 18% decrease observed after six consecutive cycles of catalyst use, clearly indicated its stability. For radiation intensities of 8, 15, 24, and 36 W, the Energy Consumed per m3 of the treated wastewater was found 20.2, 28.8, 34.1, and 36.9 kWh, respectively. From these results, namely the low energy gap (2.3 eV) and high degradation capacity, it was evident that the Pd@TMU-16 can be useful, under UV light, as a powerful catalyst in the elimination of dyes and other organic contaminants from polluted aqueous media. [ABSTRACT FROM AUTHOR]

Organic dyes are stable and persistent toxic compounds in the aquatic environment that are refractory to decompose by removal methods such as physico-chemical, optical and biological. Their presence in the aquatic media threatens human and wildlife. Herein, ZnO nanoparticles (NPs) due to good chemical durability, low cost and good photocatalytic performance was anchored on biochar (ZnO@biochar) nanocomposites were synthesized towards activation of peroxymonosulfate (PMS) for the photocatalytic removal of methyl orange (MO) dye. Several methods were used to characterization of the nanocomposites including FESEM, XRD, PL, EDS, FT-IR spectroscopy, and N2 adsorption/desorption. The results of the techniques demonstrated that the well-dispersed ZnO NPs were loaded onto the biochar surface. According to the particle size distribution graph, the average particle size of 64 nm was obtained for the ZnO NPs. BET analyzes showed that pore volume, the specific surface area (SSA) and average pore size of the synthesized nanocomposite increased. The survey of effective operational parameters indicated that the highest photocatalytic activity for MO removal was in the pH 3 of solution, 5 ppm initial dye concentration, 30 mg ZnO/biochar nanocomposite, and 20 mg PMS dose under LED-50W lamp irradiation (97.03% in the reaction time of 80 min). During the process, the reduction of the total organic carbon (TOC) contents and chemical oxygen demand (COD) were observed. Moreover, the MO degradation kinetics under optimal operating conditions were determined. It is concluded that the ZnO@biochar nanocomposite/PMS process was an efficient degradation method for the decomposition of the dye pollutant. [ABSTRACT FROM AUTHOR]

An extremely effective photocatalytic complex, PtLCl2 (1), was synthesized with (4-([2,2':6',2''-terpyridin]-4'-yl)phenyl)boronic acid as ligand and further characterized through single crystal X-ray diffraction, X-ray photoelectron spectroscopy and UV-vis spectrum. Multipoint hydrogen bonds and three kinds of π-π stacking interactions are observed in the supramolecular structure of 1. More significantly, the Pt(II) complex exhibits outstanding photocatalytic degradation efficiency (94.76%) for methyl orange within 120 min under visible light irradiation. The kinetic rate constant (k) for 1 (10 mg) is 0.02505 min−1, which is approximately 70 times higher than that of the ligand (0.00036 min−1). Moreover, its photocatalysis mechanism proposed that ·O2− and h+ were the main active species for MO degradation, providing a great prospect for development of a new efficient photocatalytic complex. [ABSTRACT FROM AUTHOR]

Green fabrication of nanoparticles (NPs) is simple, pocket-friendly, easy, sustainable, and devoid of eco-toxicity issues. Thirty-five bacterial strains were isolated from 'tie and dye' effluent-contaminated soil and effluent samples and were identified using traditional methods. Following a dye decolourization assay, Proteus mirabilis strain (NG-ABK-32) emerged as the isolate with the highest potential to decolourize vat violet RR dye. Titania nanoparticles (TiO2 NPs) fabricated using NG-ABK-32 strain were characterized by UV-visible spectroscopy (UV-vis), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), and Fourier Transform Infrared (FT-IR) spectroscopy. UV-Vis result displayed an absorption peak at 320 nm. The TEM image revealed monodispersed, spherical NPs possessing an average particle size of 3.18 nm. The crystallographic plane of rutile TiO2 NPs and high purity were confirmed by the XRD pattern. The average crystallite size was 52.53 nm. The synthesis of TiO2 NPs was further established from FT-IR by the presence of Ti-O, Ti-OH, and O-Ti-O functional groups. The synergistic treatment caused a significant reduction of total suspended solids (TSS), total dissolved solids (TDS), biological oxygen demand (BOD), chemical oxygen demand (COD), and color (Pt.Co) of the effluent by 96.86%, 78.78%, 67.84%, 56.65%, 67.84%, and 72.09% respectively. Thus, this study confirmed the better efficiency of combining biological (NG-ABK-32) pre-treatment with photocatalytic degradation post-treatment using the synthesized TiO2 NPs in the treatment of 'tie and dye' effluent compared to the application of the TiO2 NPs as a single treatment method. [ABSTRACT FROM AUTHOR]

Different compositions of manganese (x = 1 & 3 wt. %) and nitrogen (y = 1 wt. %) co-doped TiO2 (MnxNyT) photocatalysts are prepared by the conventional sol-gel method. The crystallinity, optical properties, phase purity and surface morphology of prepared nano-photocatalysts were characterised in detail. The structural analyses show that the simultaneous doping with manganese and nitrogen controls the growth of TiO2 crystal structure having an average crystallite size in the range of 14.6 to 24.5 nm. The optical analysis also demonstrated that due to the synergistic effect of Mn and N, co-doped TiO2 represents the red-shift in the absorption band edge from 3.33 eV to 2.39 eV, which improved the response of TiO2 structure towards the visible region and enhanced electron-hole separation. Among all, Mn3N1T represented the better photocatalytic efficiency against anionic dyes (Blue KBR and Red GD) and phenol under optimised conditions (such as initial substrate's concentration = 20 ppm, photocatalyst dose = 0.5 g and solution pH of 3 and 7, respectively) due to its low bandgap, low crystallite size and high absorptivity towards the visible region. The kinetics study also showed that the degradation of dyes and phenol over Mn3N1T followed pseudo-first-order kinetics. [ABSTRACT FROM AUTHOR]

AbstractWet chemical synthesis was used in this instance to create ZnO@TiO2 core-shell nanoparticles. By examining X-ray diffraction and Selected Area Electron Diffraction patterns, it was determined that the phase formation of prepared nanoparticles was a hexagonal primitive structure of ZnO and Tetragonal bcc structure of anatase phase of TiO2 devoid of impurity peaks. It was discovered that crystallites were 25 nm in size on average. The results of a surface morphology analysis utilizing High-Resolution Scanning Electron Microscopy and High-Resolution Transmission Electron Microscopy show that all of the particles are spherical. The energy dispersive X-ray spectroscopy study provided proof for the existence of core-shell elemental compositions. Fourier-Transform Infrared spectrum revealed the presence of characteristics of metal bonding with oxygen of ZnO and TiO2. UV-visible absorption analysis exhibited absorption peak in the UV region and the band gap energy of ZnO@TiO2 core-shell nanoparticles. The thermal behavior of ZnO@TiO2 core-shell nanoparticles was analyzed by using Thermogravimetric Analysis, Differential scanning calorimetry, and Differential Thermal Analysis techniques. The X-ray photoelectron spectroscopy analysis exhibited the coating of TiO2 (shell) on the surface of ZnO (core) for the formation of a core-shell nanostructure. Due to its extremely small crystallite size, wide surface area, and reduced band gap, the ZnO@TiO2 core-shell sample demonstrated outstanding photocatalytic activity when rhodamine-B dye was photocatalytically degraded in the presence of UV light irradiation. Finally, the antibacterial and antifungal activities of ZnO@TiO2 core-shell nanoparticles were investigated, and it was shown that antifungal activity was superior to antibacterial activity. A suitable material for environmental and biological applications that produced core-shell nanoparticles displayed regulated grain size, outstanding photocatalytic performance, and high antifungal activity. [ABSTRACT FROM AUTHOR]

AbstractIn this research, triethanolamine was used as a templating agent to synthesize Cu doped ZnS nanoparticles (NPs) with (1, 3, and 5 wt.%) by sol gel method. Utilizing different characterization techniques such as UV-Vis DRS, IR, XRD, BET and TEM, the produced nanocomposites (NC) were characterized. The surface area increased significantly from 57.1 to 152.4 m2 g−1 because of the computed band gap energy being diminished from 3.6 to 2.25 eV. The photocatalytic activity of the created nanoparticles was determined by destroying methylene blue dye (MB) and methyl violet (MV) under sunlight irradiation. The findings showed that the photocatalytic degradation efficiency of Cu/ZnS (5 wt.%) nano powders for MB and MV rose to 95% from 59 and 99% from 75% for undoped ZnS nanoparticles, respectively. The produced nanocomposites also proved to have excellent antibacterial action against Gram-positive bacteria S. aureus (Staphylococcus aureus) and Gram-negative bacteria E. coli (Escherichia coli) under sunlight irradiation. The antibacterial action of Cu/ZnS (5 wt.%) nano powders reached 99.9 and 96% against S. aureus and E. coli, respectively. [ABSTRACT FROM AUTHOR]

This paper reports on the optimization of fenitrothion photocatalytic degradation in visible light based on Plackett Burman (PB) design and central composite design (CCD) in response surface methodology (RSM). A herbicide routinely used with a negative impact on the environment is fenitrothion, which must be degraded to minimize the impact on the environment. For fenitrothion degradation, Ag-Au bimetallic nanoparticles on the semiconducting s-doped gC3N4 surface were synthesized using the galvanic exchange. The properties of s-gC3N4/Ag-Au bimetallic nanocomposite were confirmed by various methods. Significant factors responsible for fenitrothion photocatalytic degradation were determined using Plackett-Burman (PB) design and were catalyst dosage, initial fenitrothion concentration, H2O2 concentration, pH, and rotational speed. Central composite design (CCD) design was used for further optimization. The optimum conditions for the maximum degradation of fenitrothion (100%) constraints were found to be 100% an amount of H2O2 concentration 60 mM, pH 10, rotational speed 700 rpm. These results showed that s-gC3N4/Ag-Au bimetallic nanocomposite could act as a suitable photocatalyst under visible light in the degradation of fenitrothion. By removing fenitrothion from real water samples, as well as by maintaining its stability and reusability in five successive cycles, the practicality of this nanocomposite was demonstrated. [ABSTRACT FROM AUTHOR]

In this work, different proportions of N-doped carbon quantum dots/porous Co3O4 (NCQDs/p-Co3O4) NCQDs/Co3O4 composite photocatalysts were prepared by a simple self-assembly method. It was demonstrated by a series of characterizations that 50% NCQDs/Co3O4 has a good visible light response and low electrochemical impedance. The photocatalytic degradation of TC was investigated by the 50% NCQDs/p-Co3O4 composite photocatalyst, and the results showed that the degradation effect of TC reached 81.2% within 120 min. The higher photocatalytic activity of 50% NCQDs/p-Co3O4 was analyzed probably because NCQDs can improve the separation efficiency of photogenerated electron–hole pairs and p-Co3O4 can provide a larger specific surface area and thus has more active sites. This study provides a new strategy for improving the photodegradation activity of Co3O4 photocatalysts. [ABSTRACT FROM AUTHOR]

The photocatalytic degradation process of sulfamethoxazole (SMX) using ZnO in aquatic systems has been systematically studied by varying initial SMX concentration from 0 to 15 mgL−1, ZnO dosage from 0 to 4 gL−1 and UV light intensity at the light source from 0 to 18 W(m-lamp length)−1 at natural pH. Almost complete degradations of SMX were achieved within 120 min for the initial SMX concentration ≤15 mgL−1 with ZnO dosage of 3 gL−1 and UV light intensity of 18 W(m-lamp length)−1. The photocatalytic degradation process was found to be interacted with the dissolved oxygen (DO) consumption. With oxygen supply through the gas-liquid free-surface, the DO concentration decreased significantly in the initial SMX degradation phase and increased asymptotically to the saturated DO concentration after achieving about 80% SMX degradation. The change in DO concentration was probably controlled by the oxygen consumption in the formation of oxygenated radical intermediates. A novel dynamic kinetic model based on the fundamental reactions of photocatalysis and the formation of oxygenated radical intermediates was developed. In the modeling the dynamic concentration profiles of OH radical and DO are considered. The dynamics of SMX degradation process by ZnO was simulated reasonably by the proposed model. [ABSTRACT FROM AUTHOR]

A Zn(II)-based polyrotaxane 1D coordination polymer, {[Zn(Or)(Bimb)(H2O)]2·2H2O}n, 1 (Or = orotate; Bimb = 1,4-bis[(1H-imidazol-1-yl)methyl]benzene), has been synthesized. 1 provides for luminescent sensing of acetone, Fe3+, MnO4–, nitrofurantoin (NFT), uric acid (UA), and sucrose. The coordination polymer displays exceptional intensity quenching of ∼96.1% with 200 mg/dl of sucrose in aqueous solution. In addition, the reactivity of 1 to photocatalytically degrade the organic dye methylene blue (MB), a hazardous organic pigment, was established. 1 was able to degrade the dye due to the generation of reactive oxygen species. [ABSTRACT FROM AUTHOR]

Black AuNPs, prepared by a facile seeding growth method under ambient conditions, displayed efficient broadband absorption of the incident light over the entire visible and near-infrared regions of the solar spectrum. The spherical black AuNPs with the size of 2–4 nm were deposited over mesoporous g-C3N4 nanosheets. Novel black AuNPs/g-C3N4 plasmonic photocatalysts were used to remove methylene blue (MB) dye from an aqueous solution. The degradation efficiency for the optimal coupling of 1.3 wt.% black AuNPs with g-C3N4 (1.2 g) was found to be 85% within 60 min under visible light irradiation. The calculated kinetic constant was 0.0186 min−1 which was 6.4 and 2.9 times greater than those for g-C3N4 and AuNPs/g-C3N4 nanocomposite, respectively. The excellent potential in photocatalysis was attributed to the synergistic interactions of the g-C3N4 conduction band and the localized surface plasmon resonance effect of black AuNPs. These properties were responsible for the generation of high-energy electrons, a negative shift in the Fermi level of black AuNPs, and the migration of charge carriers. This work studied a new insight into black gold nanoparticles via the design of a visible-light-driven photocatalyst and provided a perspective on valuable photo-related applications such as water treatment. [ABSTRACT FROM AUTHOR]

Green synthesis of nanoparticles (NPs) is a revolutionary approach in terms of cost-effectiveness as well as minimization of environmental pollution by using perilousness-free bio-sources (different parts of plant, microorganism, plant-based waste). The different phytochemicals present in bio-sources play the role of potential reducing, stabilizing and capping agent during the synthesis of nanoparticles. An impetus in the rise of zinc oxide (ZnO) semiconductor has been perceived over the past decade as advanced nanomaterial to ameliorate the photocatalytic characteristics. Specifically, the use of ZnO is regarded as quite promising, not only because of the choice of green material but also owing to their alluring characteristics like high surface area to volume ratio, varying morphology etc. This review article represents several literature reports revealing the photocatalytic activities of green synthesized ZnO, prepared by using different green sources in degrading various organic pollutants which are present in wastewater. The method of derivation of phytochemicals during green synthesis approach of ZnO formation and the proposed mechanism of ZnO nanoparticles formation by interaction of those phytochemicals has been discussed thoroughly in this critical review. Numerous scientific investigations have been performed which elucidate on the controlling factors of ZnO (band gap, surface defects, surface morphology) and influence the photocatalytic activity. A summarization of such important reports has been synopsised in this article. The optimized parameters influencing the effective green synthesis of ZnO nanoparticles e.g. pH, temperature, metal precursor concentration and bio extract concentration have been concisely discussed with some published reports. Finally, a conclusion and future prospectus of the pioneering research arena are emphasized. [ABSTRACT FROM AUTHOR]

In this work, pure and Mn-doped WO3 nanoparticles (NPs) were prepared by a starch-assisted precipitation method. X-Ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Raman analysis, Fourier Transform Infrared Spectra (FTIR), Ultraviolet-Visible (UV-Vis) spectroscopy, X-ray photoelectron spectroscopy (XPS) and Photoluminescence (PL) spectroscopy were techniques to characterise the pure and Mn-doped WO3 NPs. Under sunlight irradiation, the Mn-doped WO3 NPs had been employed to degrade the organic contaminants Rhodamine B (RhB) and Crystal Violet (CV). The 10 wt% Mn–WO3 catalyst showed improved photocatalytic activity towards the degradation of CV and RhB when compared to pure WO3 and 5 wt% Mn–WO3 NPs. The Mn ions on the surface of the WO3 NPs, which hinder the recombination of photogenerated electron–hole pairs, were primarily responsible for the improvement of photocatalytic activity. A description of the photocatalytic mechanism of Mn-doped WO3 was also provided. This novel Mn-doped WO3 NPs worked well as a tool catalyst to reduce organic impurities. [ABSTRACT FROM AUTHOR]

Ecofriendly magnetic chitosan composite hydrogel (Fe3O4@CS photo-catalyst) was prepared by using an aqueous extract of Boerhevia procombens leaves for the solar light mediated catalytic degradation of lethal organic Congo red dye. The prepared composite hydrogel was structurally studied using Fourier transform infrared spectroscopy (FT-IR) which reveals the formation of the Fe3O4@CS photocatalyst. The X-ray diffraction (XRD) investigation of the composite hydrogel signified high crystallinity of photocatalyst and crystallite structure of 53 nm for magnetite nanoparticles (Fe3O4 NPs). The surface investigation suggests multilayered porous photocatalyst owing to the presence of cavities offering more photoactive sites for the photodecomposition of dye molecules. The energy dispersive X-ray (EDX) scanning supports the fabrication of Fe3O4@CS photocatalyst due to the perseverance of carbon, nitrogen, oxygen, and iron. The thermogravimetric analysis (TGA) together with vibrating sample magnetometry (VSM) certifies the preparation of thermally stable and magnetic composite hydrogel. The fabricated Fe3O4@CS photocatalyst possess low bandgap energy of 2.36 eV, supporting the excellent disintegration of dye molecules in the sunlight irradiations. The photocatalyst exhibited a maximum degradation efficacy of 99.1% for Congo red dye in the solar light irradiations with refined states of 70 min radiation time, dye concentration of 20 mg/L, pH 6, and 200 mg photocatalyst amount obeying the second-order kinetic model (R2 = 0.9959). The Fe3O4@CS photocatalyst displayed a little decrease in dissociation efficiency of dye molecules after five repeated cycles owing to the coverage or rupturing of photoactive sites. Conclusively, the results support Fe3O4@ CS to be an economical and biocompatible magnetic catalyst for the catalytic decontamination of Congo red dye molecules and other organic contaminants in domestic and industrial wastewater effluents. [ABSTRACT FROM AUTHOR]

Wastewater pollution caused by organic dyes is a growing concern due to its negative impact on human health and aquatic life. To tackle this issue, the use of advanced wastewater treatment with nano photocatalysts has emerged as a promising solution. However, experimental procedures for identifying the optimal conditions for dye degradation could be time-consuming and expensive. To overcome this, machine learning methods have been employed to predict the degradation of organic dyes in a more efficient manner by recognizing patterns in the process and addressing its feasibility. The objective of this study is to develop a machine learning model to predict the degradation of organic dyes and identify the main variables affecting the photocatalytic degradation capacity and removal of organic dyes from wastewater. Nine machine learning algorithms were tested including multiple linear regression, polynomial regression, decision trees, random forest, adaptive boosting, extreme gradient boosting, k-nearest neighbors, support vector machine, and artificial neural network. The study found that the XGBoosting algorithm outperformed the other models, making it ideal for predicting the photocatalytic degradation capacity of BiVO4. The results suggest that XGBoost is a suitable model for predicting the photocatalytic degradation of wastewater using BiVO4 with different dopants. [ABSTRACT FROM AUTHOR]

Methylene Blue (MB) is an Azo dye with benzene rings, toxic and persistent in the environment. The aim of this study was selected to evaluate photocatalytic removal of MB dye from aqueous solution using BiOI photocatalyst. Characterisation of BiOI was performed using Fourier transform infrared spectroscopy (FTIR), scanning electronic microscopy (SEM) and X-ray diffraction (XRD). A 5-level-5-factor central composite design (CCD) approach-based response surface methodology (RSM) analysis was used to statistically specify the influence of main process variables, namely contact time, dye concentration, pH and BiOI dosage. The highest removal efficiency of MB was obtained 98.5% in optimum conditions (initial concentration: 10 mg/L, pH: 9, contact time: 91.25 min, BiOI dosage: 0.77 g/L). Experimental data were well fitted to pseudo-second order kinetic model (R2 = 0.989). As a result, BiOI can be applicable for treating industrial wastewater containing dye. [ABSTRACT FROM AUTHOR]

Water pollution caused by the textile industry, increased antibiotic usage and natural pollutants has been on the rise in the last decades; hence, there is a need to find multifunctional and environmentally safe materials. In this study, we report on the facile and biosafe route for the synthesis of CuO nanoparticles using Monsonia Burkeana plant. This material was characterised using HRTEM, HRSEM, EDS, SAED, XRD, FTIR and UV-vis. The CuO nanoparticles were further tested for their photocatalytic and antibacterial activity against methylene blue (MB), malachite green (MG), sulfamethoxazole (SMX), E.coli and S.aureus, respectively. FTIR and UV-vis confirmed the formation of these materials and the deposition of the plant phytochemicals on the materials. XRD and EDS further corroborated this formation through peak identification. Through HRSEM and HRTEM, a rod-like morphology was identified and from image J measurements, they were found to be between 10 and 50 nm in particle size. Testing their photocatalytic activity against dyes, the highest degradation was achieved against MB at 83%. Reusability and trapping studies were also conducted where it was shown that the electrons were species responsible for the degradation of MB. For SMX, the degradation was pH dependent whereby at pH 7, the highest degradation of 58% was achieved. As an antibacterial agent, the green CuO was more active against E.coli and produced a complete removal (100%) using the highest concentration of 0.05 mg/ml. These results confirm that these green derived materials can be used for the treatment of various pollutants. Furthermore, their recent use in pharmaceutical degradation of antibiotics found in water will greatly assist in curbing the rise in the current emerging pollutants. [ABSTRACT FROM AUTHOR]

This work aims to study derivative removal of gentamicin (GMC) antibiotic from the aqueous solution within photocatalytic process using a recyclable magnetic titania (MT) photocatalyst. The MT photocatalyst was synthesised, characterised, and utilised by using co-precipitating method. The process of modelling and optimisation was performed by a second-order polynomial model. The 'F-value' of 432.56 and 'P-value' of 0.0001 indicated that the proposed model could be used for simulating the gentamicin photocatalytic removal process. According to the model prediction, the process could remove GMC antibiotic up to 94.7% in the optimum conditions (initial pH = 6.9, [GMC] = 20 ppm, MT dosage = 195 mg/L, and time = 63 min). Recycling and reusing potentials of the synthesised MT catalyst were studied in five cycles in the optimum conditions. According to the obtained results, in the first stage of catalyst recycling, the removal efficiency decreased by about 12%, but in the subsequent stages, the removal efficiency reduction was lower than the first step and about 5%. Mineralisation of the 51.3% efficiency was obtained in the optimum conditions. Kinetic study results showed that the data were well fitted by pseudo-first-order kinetic model with the regression coefficient of 0.9769. Also, the related reaction rate constant was 0.041 min−1. The effect of sulphate and chloride ions, as radical scavengers, on the removal efficiency demonstrated a reduction in GMC removal efficiency, which occurred by using chloride and sulphate ions. The results represented applying MT for treating real wastewater could remove GMC antibiotic in hospital wastewater up to 91.21%, too. [ABSTRACT FROM AUTHOR]

In this work, a novel hydrogel⁄Fe2O3 composite was synthesized using the microwave-induced copolymerization/sol-gel method. The synthesised hydrogel⁄Fe2O3 composite was characterised by many instruments as FT-IR, XRD, FE-SEM, CHN elemental analysis, and UV-Vis spectrophotometer. The broad peak in the XRD pattern confirms the amorphous structure of the synthesised hydrogel⁄Fe2O3 composite. The diffraction peaks at 2ϴ = 26.92°, 23.50°, and 12.80°, indexed as (013), (130), and (021), respectively confirm the presence of crystalline sheets of chitin. The presence of a peak at 2ϴ = 16.73° (154) was observed because of the presence of polyacrylamide. The synthesised hydrogel⁄Fe2O3 composite was used for the removal of acid orange 8 dye from aqueous media by the adsorption/photocatalytic method. The % removal (% R) increases with an increase in time from 5 min (% R = 14) to 25 min (% R = 52), and after that, approximate stability occurs. In the case of the presence of hydrogen peroxide and hydrogel⁄Fe2O3 composite, the % degradation (% D) under UV irradiations increases with an increase in irradiation time from 10 min (% D = 37.50) to 50 min (% D = 100). The first order is the suitable kinetic model for the description of adsorption and photocatalytic processes. [ABSTRACT FROM AUTHOR]

We report the facile synthesis of Mn doped ZnAl2O4 (MZA) (Zn1-xMnxAl2O4-δ, where x = 0.0, 0.05, 0.10, 0.15, and 0.20) nanostructured materials by simple chemical precipitation technique. Cubic crystalline structure of the samples was confirmed by XRD. Presence of metal–oxygen (Zn–O) bond in the materials was found out by FTIR analysis. The particle size analysis and SEM confirmed the presence of nanosized grains in the samples. Occurrence of appropriate amount of Zn, Al, O, and Mn was detected by EDAX analysis. The optical characteristics of Zn1-xMnxAl2O4-δ were studied using UV spectral studies. The band gap of these materials was found to be in the range of 2.65 to 3.001 eV. The photocatalytic degradation of malachite green (MG) dye over Zn1-xMnxAl2O4-δ nanoparticle suspensions in presence of visible light was investigated in aqueous solution. Zn0.8Mn0.2Al2O4-δ could degrade 57% of MG dye after 120 minutes of irradiation at room temperature. [ABSTRACT FROM AUTHOR]

Methyl orange (MO) is a colored dye and hazardous organic pollutant, which poses threats to human health and the environment. Photocatalytic degradation is widely used to remove MO in water because of its high efficiency and no harmful pollution products. The photocatalytic degradation efficiency of titanium dioxide (TiO2) catalysts has been limited by photogenerated electron/hole recombination. Multi-walled carbon nanotubes (MWCNT) can improve the separation and migration rate of photogenerated electrons. The poly(vinylidene fluoride) (PVDF) membrane with good flexibility, good connectivity and easy recovery, can be selected as carrier material for the photodegradation of MO in water. Here, the hydrophilic TiO2@MWCNT/PVDF membrane was synthesized to photodegrade MO in water and showed excellent pollutant removal efficiency (80%). The novel TiO2@MWCNT/PVDF membrane is a promising photocatalyst for degrading organic pollutants in water. [ABSTRACT FROM AUTHOR]

High photocatalytic activity composites of TiO2/acid-activated kaolinite (T/AK) were optimally constructed utilizing a simple hydrothermal method for the high-performance photocatalytic degradation to sodium ethyl xanthate (SEX) in mineral processing wastewater in this work. The synthesized T/AK composites under different preparation conditions were characterized by SEM, TEM, XRD, XPS, and UV-vis DRS to determine their structure, morphology, elemental composition, and photochemical properties. Compared with pristine TiO2 and kaolinite, the T/AK composites exhibited enhanced photocatalytic degradation performance to SEX due to their synergistic effects of adsorption and catalysis. The photocatalytic degradation efficiency of 0.4 g/L of 0.6T/AK composites to 30 mg/L of SEX reached 94% in 50 min under optimal preparation conditions, demonstrating that T/AK composites photocatalysts could effectively degrade toxic and corrosive SEX. The active radical studies revealed that the most significant active component in the photocatalytic system is h+ . The enhanced photocatalytic activity originated from its large specific surface area and suppressed the recombination rate of the photogenerated carriers of T/AK composites, which makes them great potential in wastewater treatment of mineral processing. [ABSTRACT FROM AUTHOR]

Green synthesis of silver nanoparticles (AgNPs) has attracted substantial interest and achievement due to their environmental friendliness, ease of manipulation, and potential for large-scale production. By using aqueous Camellia sinensis leaf extract, suspensions of AgNPs, which possess photocatalytic and biological activity, were successfully synthesized in this study. The reduction of silver ions to AgNPs was visually inspected via the colour of the reaction mixture, which was altered from pale yellow to reddish brown. The methods of characterization of the as-synthesized AgNPs were performed using Ultraviolet-Visible spectroscopy (UV-Vis), dynamic light scattering technique (DLS), and X-ray diffraction analysis (XRD). The surface plasmon resonance bands of AgNPs at 420-430 nm in UV-Vis spectra indicated the presence of silver particles at the nanoscale. The size of AgNPs was determined by DLS, ranging from 25 nm to 40 nm. XRD analysis showed that AgNPs were highly pure and crystalline. The antibacterial activity of AgNPs against Gram-positive and Gram-negative bacterial strains, including Staphylococcus aureus and Escherichia coli, respectively, was demonstrated by the disc diffusion method. The examination of the photocatalytic activity of AgNPs was conducted through methylene blue (MB) degrading experiments, and the MB degrading performance was approximately 95% within 72 h under sunlight. [ABSTRACT FROM AUTHOR]

Caffeine (CAF) is a widely used stimulant in beverages, foods, and drugs. Extreme usage of this popular molecule can create caffeine pollution for water sources. A photocatalytic method was developed to degrade CAF in water. The pillared interlayered clays (PILCs) were used as the photocatalytic material. Zeolite, a type of clay, was used to prepare PILCs. The operational parameters, such as reaction time, CAF concentrations, H2O2, and PILCs amounts, were examined to obtain the highest removal percentages. The removal rates reached 97%, 100%, and 100% in 120, 180, and 300 min, respectively, using 1.0 mL H2O2 and 1.0 g of Fe-Ti-PILC for 50.0 mg/L CAF under UV exposure. The experiments were carried out in batch method, and RP-HPLC was used to find the remaining CAF concentrations. [ABSTRACT FROM AUTHOR]

The post-treatment of recycling the fine photocatalyst nanoparticles restricts their application. In this study, a new photocatalytic material was synthesized by immobilizing the N-doped TiO2 and graphene oxide (GO) composite on polypropylene (PP) (N–TiO2/GO/PP) fibre sheet, and characterized based on X-ray diffraction spectroscopy (XRD), Raman spectroscopy and Scanning Electron Microscope (SEM). The photocatalytic activity was evaluated using roxithromycin (ROX) as a typical antibiotic pollutant. XRD, Raman spectra and SEM images proved that N–TiO2/GO/PP fibre sheet was successfully synthesized. The photocatalytic degradation of 10 mg L−1 ROX can reach up to 90% and the degradation rate constant was 0.2299 h−1 in surface water with the application amount of TiO2/GO/PP fibre sheet of 24.6 cm × 2.7 cm and reaction time of 9 h under the irradiation of simulated sunlight. The application amount of TiO2/GO/PP fibre sheet, initial concentration of ROX and water matrix significantly affect the degradation of ROX. A low concentration of natural organic matter (NOM) slightly promoted the degradation of ROX, while a high concentration of NOM significantly inhibited the degradation of ROX. Alkaline condition (pH 8–9) is favourable for the photocatalytic degradation of ROX by TiO2/GO/PP fibre sheet. The photocatalytic reactivity of the TiO2/GO/PP fibre sheet showed no significant decrease after three runs. Two primary degradation products of ROX were identified and they showed lower ecotoxicity than ROX. The results demonstrate that the new synthesized TiO2/GO/PP fibre sheet shows promising application prospects in the treatment of antibiotics in wastewater and surface waters. [ABSTRACT FROM AUTHOR]

Ag3PO4 photocatalysts were successfully synthesized via a simple precipitation method. The photocatalytic performance of the synthesized Ag3PO4 was evaluated through the degradation of Rhodamine B (RhB) under visible light illumination. Photodegradation efficiency was up to 98.36% within 20 min. Ag3PO4 had good stability and the contribution of active species during degradation was: h+ > ·O2− > ·OH. This work would provide a new perspective for improving the application of environmental remediation. [ABSTRACT FROM AUTHOR]

A ternary composite α-DMACoPc/UiO-66-NH2/TiO2 was synthesized by solvothermal method and characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) and other means. The composite catalyst was applied to decompose methylene blue dye in visible light, and the degradation rate reached 93.4%. Compared with the monomer, the composite significantly enhanced the efficiency of the catalytic degradation due to the synergistic effect between composites. The transport speed of charge is accelerated and the recombination of hole-electron pairs is inhibited due to the larger specific surface area. A feasible scheme was provided for preparation of composite catalyst and photocatalytic degradation of dye. [ABSTRACT FROM AUTHOR]

Effective textile dye removal from aquatic wastewater is essential, as this effluent is harmful to human health, biodiversity, and natural environments. This study investigates the synthesis of zeolitic materials for dye removal from wastewater using metakaolin and fly ash as starting materials. In the first synthesis step, the starting materials are blended at various metakaolin-to-fly ash ratios and treated with a 3 M sodium hydroxide solution under stirring. The solid-to-liquid ratio of the precursor gel is 1:8 (w/v). The suspensions are then subjected to hydrothermal treatment at 120 °C for 6 h. In the second step, an impregnation method is used to obtain titanium dioxide (TiO2)-containing zeolite, and the effect of the TiO2 content on the zeolite adsorption performance is investigated. The synthesized products are characterized using X-ray diffraction, scanning electron microscopy, particle size analysis, surface area measurement, and ultraviolet-visible spectrophotometry. From the results, a metakaolin-to-fly ash weight ratio of 4:1 is optimal and yields sodalite and zeolite A. For 20-ppm methylene blue solution, the adsorption efficiencies of freshly synthesized zeolite and TiO2-containing zeolite are found to be 87.63% and 99.87%, respectively. In addition, the adsorption performance of the reused product is similar to that of the freshly synthesized product. Thus, the synthesized modified zeolite is an efficient adsorbent for methylene blue removal. Blending of metakaolin (MK) and fly ash (FA) as a starting material for preparing microporous materials. TiO2/zeolite composites were simply prepared for methylene blue (MB) removal. TiO2/zeolite composites can improve photocatalytic degradation of MB. TiO2/zeolite composites had a better MB removal efficiency than zeolite. The degradation rate of MB dye by TiO2/zeolite composites reached 99.87%. [ABSTRACT FROM AUTHOR]

At present, the water pollution caused by antibiotics has seriously affected the ecological balance and human health. The development of a novel and efficient visible-light-responsive semiconductor photocatalysts is of great significance for the degradation of ciprofloxacin by visible light. In this study, solvothermal method was used to prepare ZnO and ZnO/Cu2O composite particles. The effects of ZnO addition on the microstructure, surface morphology and photoelectric properties of composite particles were studied by XRD, XPS, SEM, BET and UV-Vis techniques. The kinetics of photocatalytic degradation of ciprofloxacin by ZnO/Cu2O composite particles and the contribution of different active species in the degradation process were studied. The results show that the purity of the prepared product is high. ZnO/Cu2O has an octahedral morphology. Compared with Cu2O, ZnO/Cu2O has a clear difference, the absorbance is reduced, the band gap is increased, and the surface fitting resistance is significantly reduced. Among them, R3 sample has highest purity and degree of recombination, the surface fitting resistance is the smallest, the separation efficiency of photogenerated electrons and holes is improved, and the photocatalytic performance is improved. The degradation rate of ciprofloxacin by R3 sample is 80.4%, and the degradation of ciprofloxacin conforms to the first-order kinetic equation. After 5 repeated experiments, the ciprofloxacin degradation rate can still reach 75.3%, indicating that the composite material has good stability and reusability. Studies on active species in the process of degradation showed that ·OH played a major role in the degradation of ciprofloxacin. [ABSTRACT FROM AUTHOR]

ZnO was impregnated with Ni in order to increase its photocatalytic performance in the visible region. The Ni-impregnated ZnO catalyst was synthesized by wet impregnation. The synthesis of Ni/ZnO catalyst, its morphological analysis and elemental analysis was confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectroscopy which confirmed that 4.66% Ni was impregnated at the surface of ZnO. The synthesized catalyst was applied for the photocatalytic degradation of Remazol Brilliant Violet-5R (RBV-5R) and methyl orange (MO) in aqueous solution. The catalyst dosage, pH, dye concentration, and effect of scavengers were optimized. 98.92% degradation of RBV-5R was observed at pH 10 using 0.1 g of catalyst, 5 mmol H2O2 in 20 min, whereas 83.77% MO was degraded using 0.2 g of the catalyst at pH 4 in 30 min. The order of reaction was also determined by applying kinetic models and the degradation followed pseudo first-order kinetics for both dyes. [ABSTRACT FROM AUTHOR]

Lead tungstate nanoparticles (PbWO4 NPs) and PEG capped PbWO4 nanoparticles (PEG/PbWO4 NPs) were synthesized by co-precipitation technique. Vibrational, structural, optical and morphological properties of the as-prepared nanoparticles were observed by FTIR, XRD, UV-vis and SEM techniques. These nanoparticles show a tetragonal stolzite crystalline structure. The quantum confinement of nanoparticles was confirmed by UV-vis spectrum. Since polymeric modifying agent, polyethylene glycol (PEG) performs as a stabilizer and also helped to unite the surface of the PbWO4 NPs. FTIR established the functional groups in PEG united with the PbWO4 NPs and reduction took place in the reaction medium. The adsorbed PEG onto the PbWO4 NPs initiated the negative charge onto the particle surface and thus repelled the particles away from one another, hindering them from aggregation. The formation of quasi-octahedrons was confirmed from SEM images. The consequences of the antimicrobial study prove that the better capability of PEG/PbWO4 NPs to inhibit the growth of Staphylococcus aureus, Pseudomonas aeruginosa, and Aspergillus niger. This study signified that PEG is an effective surfactant for morphology control, reduction of crystallite size, photocatalytic degradation of methyl orange and antimicrobial activity of PbWO4, maybe because of the steric impediment it grants. [ABSTRACT FROM AUTHOR]

In this study, a new reactor was carried out to recover UV solar radiation to degrade the methylene blue (MB) and methyl orange (MO) dyes using the raw phosphate doped by TiO2. The raw phosphate (Pht), TiO2, and TiO2/doped phosphate (TiO2/Pht) were characterized by several techniques to determine their physicochemical properties. The performance of MB and MO photocatalytic degradation was very high around 88% for MO and 99% for MB using 1 g of TiO2/Pht at midday. This new process is capable of degrading the high concentrations of dyes in water, especially the azo dyes which are hard to treat. [ABSTRACT FROM AUTHOR]

In this work, novel NiS–Analcime composite was facilely synthesised via ion exchange of analcime with Ni(II) ions then precipitation of Ni(II)-Analcime utilising Na2S. Also, the synthesised composite product was characterised using XRD, FT-IR, TGA, FE-SEM, and UV-Vis techniques. Besides, the synthesised composite was employed as a photocatalyst for the photocatalytic degradation of Eriochrome Black T dye under the influence of ultraviolet irradiation. Moreover, the influence of important operating factors such as time, pH, temperature, dosage of catalyst, and primary concentration of Eriochrome Black T dye was studied. Furthermore, the results confirmed that 50 mg of NiS-Analcime composite decomposed 99.48% of 50 mL of 50 mg/L Eriochrome Black T dye within 100 min at pH = 7.5 and temperature = 25 °C. In addition, the photocatalytic degradation process followed by first-order. [ABSTRACT FROM AUTHOR]

Glutamine-assisted SnO2 nanorods with an average crystallite size of 48.38 nm were facilely fabricated using the hydrothermal procedure. Also, the fabricated sample was characterised using XRD, FT-IR, FE-SEM, HR-TEM, and UV-Vis spectroscopy. The glutamine deeply influences the crystallite size and morphology of the fabricated SnO2. Moreover, the UV–Vis shows a broad absorption spreading into the visible light region. Furthermore, depend on Tauc's plot, the optical energy gap of the fabricated sample is 2.85 eV. Besides, the photocatalytic activity of the fabricated sample was examined by observing the degradation of crystal violet dye under visible light irradiation. The photodegradation efficiency of crystal violet dye over glutamine-assisted tin oxide nanorods is 97.38% within 60 min. Additionally, the fabricated photocatalyst is characterised by the reusability for several times without losing its efficacy. [ABSTRACT FROM AUTHOR]

The microcystin-LR (MC-LR) is a potentially dangerous toxin for animals and human health. So, MC-LR removal from the environment by the use of photocatalysts is recommended. Generally, traditional photocatalysts are dependent on UV light and consume high energy and also produce high heat. So, the use of photocatalysts with low-energy consumption, feasible, and reliable properties that activate in the visible light is very important. The aim of the present study was the removal of microcystin-LR (MC-LR) in visible light by synthesised bismuth vanadate (BiVO4) with the hydrothermal method. The BiVO4 characteristics were determined by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FT-IR) spectra. The Response Surface Methodology (RSM) was used to survey the effects of operating variables such as pH, contact time, and catalyst dose on MC-LR removal. The results showed that the increase of contact time and catalyst dose had a positive effect on enhancing the removal efficiency of MC-LR, but the effect of pH was negative. The maximum removal efficiency of MC-LR at pH = 5, contact time = 180 minutes and catalyst dose = 0.5 g/l was equal to 93.19%. Therefore, BiVO4 as an innovative photocatalyst had a suitable effect on the MC-LR degradation under visible light. [ABSTRACT FROM AUTHOR]

The g-C3N4 has been reported as a promising candidate for promoting photocatalytic activities by reducing the recombination of electrons and holes. Nanostructured materials titanium dioxide (TiO2) is the best photocatalysts but is restricted due to photo-efficiency and limited light response due to its wide bandgap. The heterostructures improve binding sites' efficiency and provide more active sites for photocatalysis. The heterostructure TiO2/g-C3N4 prepared hydrolysis method and used a certain amount of TiCl4. The samples have been characterised by using FTIR, XRD, SEM, UV–Vis Spectroscopy, BET, and TGA. For photocatalytic activity, the TiO2/g-C3N4 shows better photocatalytic activity and kinetic study compared to g-C3N4 and TiO2 due to the formation of heterojunction. The photocatalytic activity parameters were different dyes and applications. Both methylene blue and caffeine degraded well under UV light irradiation, with methylene blue reaching nearly 100% after 240 minutes and phenol reaching 74.66% after 300 minutes. The mechanism of photodegradation has been thoroughly examined. [ABSTRACT FROM AUTHOR]

ZnS:Mn-gly and C60 fullerene nanowhisker–ZnS:Mn-gly composites were synthesized and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and Raman spectroscopy. The photocatalytic degradation of methylene blue (MB) under UV light irradiation was evaluated by UV-vis spectroscopy using ZnS:Mn-gly and C60 fullerene nanowhisker–ZnS:Mn-gly composites. The C60 fullerene nanowhisker–ZnS:Mn-gly composites showed better photocatalytic activity of MB degradation than the ZnS:Mn-gly composites. The kinetics study for the photocatalytic degradation of MB with ZnS:Mn-gly and C60 fullerene nanowhisker–ZnS:Mn-gly composites as photocatalyst under UV irradiation followed a pseudo-first-order reaction rate law. The stability of the photocatalysts after the photocatalytic reaction was studied using XRD and SEM. [ABSTRACT FROM AUTHOR]

Titanium dioxide-doped graphene aerogel (TiO2/GA) was synthesized via one-pot the hydrothermal method. The characterisation of the prepared nanocomposite was thoroughly investigated with various modern analysis method. The results revealed a good terms in both of photo–absorption and nanoparticle sizing. The low band-gap energy of 2.61 eV and the larger specific surface area of TiO2/GA are the main differentiators when compared to the pristine materials. The size of TiO2 nanoparticles has been observed to range from 5 to 20 nm, which is necessary to promote a high photocatalytic performance. The photocatalytic performance of TiO2/GA was examined through photodegradation of p-nitrophenol (PNP). The optimization via Box-Behnken model suggested that 99.89% of PNP could be removed at the pH 7, 20 mg photocatalyst dosage, and 1 mL H2O2 volume. With the excellent results obtained, TiO2/GA material has extensive promise in the emoval of phenolic. [ABSTRACT FROM AUTHOR]

The homogeneous Cu–ZnO and heterogeneous Ag/ZnO nanorods were synthesised by controlling the ionic radius of Cu and Ag with lattice of ZnO. The structure of Cu–ZnO and Ag/ZnO was investigated by a series of methods. The study of the photoelectric properties suggested both the homogeneously and heterogeneously doped ZnO displayed an increased photocatalytic performance. It was worth noting that the Cu–ZnO and Ag/ZnO composites shown different degradation activities of methylene blue under the visible and UV light irradiation. The data suggested that the Cu species incorporated into the crystal lattice of ZnO nanorods could promote the utilisation of visible light, leading to 2.5- and 2.7-fold increase in the degradation rates compared with Ag/ZnO and ZnO nanorods. However, when UV light was employed, on the one hand, the significant increase of the activity for both Cu–ZnO and Ag/ZnO compared with ZnO was observed and on the other hand, the degradation rate of Cu–ZnO was close to that of Ag/ZnO. The investigation suggested that the metallic Cu in the ZnO crystal lattice could promote the separation of electrons and holes generated by ZnO under visible light. As for the UV light, both doping styles could favour the separation process. The present work could provide a further insight for the design of ZnO-based nanomaterials and development of their applications in environmental catalysis. [ABSTRACT FROM AUTHOR]

The photocatalytic reduction of methylene blue was recognized as an economical and effective way for dye removal. To enhance photocatalytic activity under visible-light condition, fluorine and graphene synergistically modified TiO2 (F-TiO2/rGO) nanocomposites were successfully prepared by sol–gel method. Characterization results showed F ions played an essential role in the formation of TiO2 nanoparticles. Between the fluorine sources selected, NH4F was more optimal than NaF doping on the grounds that the existence of Na+ ion was an inevitable factor for the production of brookite. F-TiO2/rGO nanocomposite obtained by adding 5%at NH4F significantly narrowed the bandgap energy from approximately 3.17 to 2.41 eV. Box–Behnken design was adopted to optimize the MB photo-degradation process by F(5%NH4F)-TiO2/rGO nanocomposites under different reaction conditions. Moreover, the antibacterial behaviour of this novel material was also investigated by Escherichia coli (E. coli) bacteria under visible light. The morphology changes of E. coli cells were directly observed by field emission scanning electron microscope and further confirmed that the excellent sterilization of F-TiO2/rGO nanocomposites resulted from the active species. The outstanding photocatalytic performance and antibacterial behaviour of F-TiO2/rGO nanocomposite was attributed to the synergistic effect of photocatalytic redox reaction and adsorption. These results indicated F(5%NH4F)-TiO2/rGO nanocomposite was a promising antibacterial photo-adsorbent for wastewater treatment improvement. [ABSTRACT FROM AUTHOR]

Trichloroacetic acid (TCAA) is considered as one of the major of water chlorination by-products. The present work demonstrates decomposition, mineralisation and dechlorination of TCAA by photocatalytic reduction using F doped TiO2. In this regard, the effects of various operational factors including F-TiO2 dose, the initial concentration of TCAA, photo-reaction time and solution pH were examined on the process efficiency. Based on the results, H C O 3 − , P O 4 − 3 , S O 4 − 2 , C l − and C O 3 − 2 , as the common anions in water, had no considerable impact on the TCAA degradation efficiency. Decomposition and mineralisation rate of TCAA by MeOH/UV/F-TiO2process under the optimum conditions (catalyst dosage of 0.34 g L−1, the contact time of 76 min, TCAA content of 1 mg L−1 and pH of 7.9) were found to be 97.1% and 68%, respectively. The decomposition intermediates of TCAAdetected by LC/MS and LC-MS/MStechniques were non-chlorinated compounds, mainly formic and acetic acids. It can be concluded thatMeOH/UV/F-TiO2processcan use as low energy and efficiently treatment method for the degradation of TCAA contaminated water and wastewater. [ABSTRACT FROM AUTHOR]

The aim of the present study was to synthesis Ni-doped TiO2 nanoparticles (NPs) in order to evaluate their effectiveness in photocatalytic degradation of formaldehyde in the aqueous phase. The Ni-doped TiO2 NPs were synthesised using a mild hydrothermal method. They were then immobilized on glass plates by the calcination method. Characterisation of Ni-doped TiO2 NPs was also carried out using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The SEM images showed the uniform distribution of as-synthesised NPs on the surface of glass plates, with multidimensional crystalline structures. The results indicated that increasing the dopant weight ratio to 0.7% enhanced the photocatalytic degradation efficiency of formaldehyde; however, a further increase in the dopant weight ratio reduced the process efficacy. According to the results, increasing the initial pH from acidic and neutral to alkaline conditions decreased the efficacy of the process. Furthermore, the results showed that increasing the amount of nanocatalyst and decreasing the initial concentration of formaldehyde favoured the photocatalytic degradation of formaldehyde. [ABSTRACT FROM AUTHOR]

A new type of photocatalysts, nanocrystalline titanium dioxide (TiO2) doped with Co and I, were synthesized and modified via the sol-gel method to enhance the utilization of visible light. Herein, mono- and co-doped TiO2 (i.e. Co-TiO2, I-TiO2, Co-I-TiO2) were employed as the photocatalysts to investigate the photocatalytic performance on gaseous benzene removal. The prepared photocatalysts were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET)-specific surface areas, Raman spectroscopy, UV-visible diffuse reflectance spectroscopy (UV-vis-DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and electrochemical impedance spectroscopy (EIS). Results indicated that both particle sizes and band gaps of TiO2 were significantly reduced by doping with Co/I. Also, the lattice defects and the specific surface areas of TiO2 were substantially augmented by adding Co/I because of the increase of oxygen vacancies, especially for Co-I-TiO2. Meanwhile, Co and I were distributed on the titanium base with the existence of multivalent states. The benzene treatment capacity of Co-I-TiO2, Co-TiO2, I-TiO2 and Pure TiO2 is 441.46, 424.36, 388.06, and 51.25 μgC6H6/(g·h), respectively. To sum up, photocatalytic degradation of gaseous benzene could be improved by doping with Co/I because of the extension of catalyst lifetime and light response range covering visible light. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) entering into soils via sewage sludge could be posing arresting environmental risks. Photocatalytic remediation has been considered as a powerful tool of degrading PAHs in soils. In the present study, a synthesized nanometer mixed-crystal TiO2 was employed to investigate its effects on PAHs degradation in soils by Ultra Violet (UV).Two typical substances of PAHs widely detected in sewage sludge (phenanthrene and pyrene), were added into soils from farmland to provide polluted soil for a series of simulated experiments. These polluted soil samples were mixed with five different levels of the synthesized TiO2 (0, 1%, 2%, 3%, and 4%, wet weights) and the decreases of PAHs under different conditions were compared. The results showed that among the five treatments, the activities of the synthesized photocatalysts followed the order of 0<1%<2%<4%<3%, and the 3% of TiO2 addition was determined as the optimum condition. Moreover, it was found that the degradation of PAHs could increase with the increasements of H2O2, photon flux, and humic substances in treated soils. Our findings supports the perspective of using nanometer synthesized mixed-crystal TiO2 in the degradation of PAHs in contaminated soils by sewage sludge addition and provides hints on understanding the mechanism of developing photocatalytic remediation in PAHs-contaminated soils. [ABSTRACT FROM AUTHOR]

SiO2-CNFs composites were prepared by electrospinning and calcination with change of the dosage of SiO2 nanoparticles into electrospinning precursor solution. CuS nanosheets were controllably grown on the surface of SiO2-CNFs through hydrothermal method, which was characterized by SEM, FTIR, TEM, XRD, and XPS techniques. The results showed that multi-hydroxyl on the surface of SiO2 provided active sites to attract Cu2+. Hence, SiO2 modified CNFs had the function of directional anchoring CuS nanosheets. The photocatalytic degradation of tetracycline using CuS-SiO2-CNFs was further investigated. Compared with CuS-CNFs and CuS-2%SiO2-CNFs samples, the CuS-1%SiO2-CNFs had the optimal photocatalytic activity, which was attributed to that CuS nanosheets were homogeneously dispersed on the surface of 1%SiO2-CNFs. [ABSTRACT FROM AUTHOR]

SiO2-CNFs composites were prepared by electrospinning and calcination with change of the dosage of SiO2 nanoparticles into electrospinning precursor solution. CuS nanosheets were controllably grown on the surface of SiO2-CNFs through hydrothermal method, which was characterized by SEM, FTIR, TEM, XRD, and XPS techniques. The results showed that multi-hydroxyl on the surface of SiO2 provided active sites to attract Cu2+. Hence, SiO2 modified CNFs had the function of directional anchoring CuS nanosheets. The photocatalytic degradation of tetracycline using CuS-SiO2-CNFs was further investigated. Compared with CuS-CNFs and CuS-2%SiO2-CNFs samples, the CuS-1%SiO2-CNFs had the optimal photocatalytic activity, which was attributed to that CuS nanosheets were homogeneously dispersed on the surface of 1%SiO2-CNFs. [ABSTRACT FROM AUTHOR]

Using the response surface method (RSM), the temperature, time and nickel-iron ratio of the synthesis of NiFe-LDH photocatalyst were used as influencing factors, the removal rate of norfloxacin (NOR) was the response factor, the Sub-mathematical equation was structured. The optimized model predicts that the optimal synthesis temperature, time and nickel-iron ratio are: 127.1 °C, 36 min, 2.854:1, and the removal rate of NOR is 88.25%. The actual removal rate of NOR over NiFe-LDH prepared under the conditions was 89.14%, indicating that the model was successfully established. It provides a reference for the synthesis of hydrotalcite by microwave method. [ABSTRACT FROM AUTHOR]