Photocatalytic Degradation Of Salicylic Acid Research Articles

Cu/Nb2O5, Fe/Nb2O5 and Cu-Fe/Nb2O5 applied in salicylic acid degradation: Parameters studies and photocatalytic activity

This study describes the synthesis of Cu/Nb2O5, Fe/Nb2O5, and Cu-Fe/Nb2O5 catalysts obtained by incorporating copper and/or iron metals into niobium pentoxide (Nb2O5). The new materials were characterized by the following techniques: Thermogravimetric Analysis (TA), surface and pore analysis, X-ray diffractometry (XRD), and Fourier Transform Infrared Spectroscopy (FT-IR). The catalyst was applied in the photocatalytic degradation of salicylic acid (SA). The influence of different parameters (calcined temperature, pH, and metal addition) on the photocatalytic reaction was evaluated. The results indicated that catalysts containing copper were more active and pH influenced the SA degradation process. SA removal results indicated that Cu/Nb2O5 photocatalyst presented a 1.5 fold higher degradation after 120 min in comparison to Cu-Fe/Nb2O5 and 4.6 fold higher than Fe/Nb2O5 catalyst, all them calcined at 400 °C. In tests carried out in the presence of formic acid, increasing the pH from about 3 to 7 allowed an almost 3.4-fold increase in SA degradation for the Cu-Fe/Nb2O5 catalyst calcined at 400 °C.

Photocatalytic degradation of salicylic acid employing TIO2 and ZNO in aqueous suspension / Degradação fotocatalítica do ácido salicílico empregando TIO2 e ZNO em suspensão aquosa

The photocatalytic degradation of salicylic acid (SA) in reduced concentration (14.5 µmol L-1) was investigated using TiO2 and ZnO as photocatalysts under irradiation with UV light using UV-Vis spectrophotometry and HPLC analysis. The effect of different catalysts and catalyst loading, kinetic analysis, and dissolution of ZnO using the experimental conditions adopted were evaluated in acidic medium (pH = 3.0). Chronic ecotoxicity tests of the effluent from the reactions were conducted employing a concentration of 1 g L-1 of photocatalysts. The results showed that TiO2 and ZnO presented very similar performance for the SA degradation, whose profile followed first-order kinetics. The dissolution of ZnO observed was low using the experimental conditions adopted. Chronic ecotoxicity tests carried out showed that the use of ZnO/UV system for degradation of SA leads to a product with significant harmful effects on Ceriodaphnia dubia, even at reduced concentrations of the effluent from the reaction.

Molecular imprinting produces high photoelectric effect facilitating the efficient photocatalytic degradation of salicylic acid by TiO2

Molecular imprinting produces high photoelectric effect facilitating the efficient photocatalytic degradation of salicylic acid by TiO2

Photocatalytic Degradation of Salicylic Acid in Water Under Different Irradiation Conditions in the Presence of Doped (N, Fe) Titanium Dioxide

Photocatalytic Degradation of Salicylic Acid in Water Under Different Irradiation Conditions in the Presence of Doped (N, Fe) Titanium Dioxide

Enhanced photocatalytic performance of ultrasound treated GO/TiO2 composite for photocatalytic degradation of salicylic acid under sunlight illumination.

The current research work deals with the preparation of TiO2 and GO/TiO2 composite by simple, chemical, cost effective hydrothermal method. Graphene oxide (GO) is prepared by modified Hummer's method. Dispersion of GO is achieved by an ultrasonic cleaning bath for 1 h. using a power of 200 W and at a frequency of 40 kHz. The prepared catalyst material is characterized by different characterization techniques. XRD study confirms the prepared material is polycrystalline in nature. The synthesized TiO2 and GO/TiO2 photocatalyst materials are used to study the photocatalytic degradation of salicylic acid under sunlight illumination. GO/TiO2 composite shows superior photocatalytic activity than TiO2. GO/TiO2 composite shows 57% degradation of salicylic acid. Mineralization of salicylic acid is studied using chemical oxygen demand.

Effect of the preparation method and metal content on the synthesis of metal modified titanium oxide used for the removal of salicylic acid under UV light

ABSTRACTTitanium dioxide modified with Ag and Fe was synthesized using two preparation methods, characterized and applied to the photocatalytic degradation of salicylic acid in aqueous solution. The modified TiO2 samples were prepared by the sol–gel and wet impregnation methods starting from titanium(IV) isopropoxide and using AgNO3 and Fe(NO3)3·9H2O as precursors of the modifiers, with their content varying between 0 and 5 wt.%. Catalysts characterization was based on powder X-ray diffraction (PXRD), nitrogen physisorption at 77 K, temperature programmed reduction (H2-TPR), chemisorption of NH3 at 343 K and X-ray photoelectron spectroscopy (XPS). The photocatalytic degradation of salicylic acid by modified TiO2 was investigated under ultraviolet irradiation at 298 K considering various concentrations of the catalyst, between 100 and 1000 mgcatalyst/dm3, and of the organic molecule, between 0 and 15 mg/dm3. The catalysts most active in the degradation of salicylic acid were those having the highest Fe content.

Photocatalytic degradation of salicylic acid using BaTiO3 photocatalyst under ultraviolet light illumination

The present study deals with the preparation of tetragonal barium titanate (BaTiO3) by hydrothermal technique and its use in the photocatalytic degradation of salicylic acid. The structural, morphological, and photocatalytic properties of the BaTiO3 nanoparticles are studied. The prepared samples are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscope (SEM) and Ultraviolet–visible (UV–Vis) spectroscopy. The end result shows that the degradation percentage of salicylic acid using BaTiO3 photocatalyst has reached 51% under ultraviolet light illumination after 120 min. The amount of degradation is confirmed by COD analysis.

Facile preparation of CuO/g-C3N4 with enhanced photocatalytic degradation of salicylic acid

CuO particles supported on graphitic carbon nitride (g-C3N4) nanosheeets were prepared using a novel one-pot method. In the presence of ammonium nitrate, different mass ratios of copper nitrate/melamine were used to fabricate these catalysts, which were characterized using XRD, N2-physisorption, FT-IR, TEM, XPS and UV–vis analysis. The catalytic performance of CuO/g-C3N4 was evaluated by photodegrading salicylic acid under visible-light irradiation. Among these novel catalysts, CuO(1.0)/g-C3N4 was found to exhibit the highest catalytic activity, which was more than 100% greater than the parent g-C3N4 material. The improved photocatalytic properties of CuO/g-C3N4 may be ascribed to the formation of p-n heterojunctions between CuO and g-C3N4, resulting in the effective separation of photogenerated electron-hole pairs and the enhanced absorption of visible light. Furthermore, the CuO/g-C3N4 composites had excellent stability and reused for five times without obvious loss of activity.

Effect of preparation methods on the activity of titanium dioxide-carbon nitride composites for photocatalytic degradation of salicylic acid

In this study, titanium dioxide-carbon nitride (TiO2-CN) composites were prepared by three methods, which were one pot oxidation, impregnation, and physical mixing. Each series of the photocatalysts was prepared with different ratios of titanium to carbon (Ti/C), i.e., 1, 5, 10, 20, and 50 mol%. All samples were characterized by X-ray diffraction (XRD) and diffuse reflectance ultraviolet-visible (DR UV-Vis) spectroscopies. The characterization results confirmed the successful preparation of TiO2, CN, and the TiO2-CN composites. Photocatalytic activity tests were carried out for degradation of salicylic acid at room temperature for 6 h under UV and visible light irradiations. It was confirmed that all the prepared TiO2-CN composites showed better photocatalytic activities than the bare TiO2 and the bare CN. Under UV light irradiation, 90.6% of salicylic acid degradation was achieved on the best composite prepared by one pot oxidation with 5 mol% of titanium to carbon (Ti/C) ratio. On the other hand, the highest degradation under visible light irradiation was 94.3%, observed on the composite that was prepared also by one pot oxidation method with the Ti/C ratio of 10 mol%. Therefore, among the investigated methods, the best method to prepare the titanium dioxide-carbon nitride composites with high photocatalytic activity was one pot oxidation method.

Novel synthesis method for photo-catalytic system based on some 3d-metal titanates

In this paper, we studied titanium (TiO2) nanoparticle in three different structures (Anatase, Rutile, and Degussa) and then they were synthesized by the sol–gel method which is used butanol, toluene, and triethylene glycol as solvent at different temperatures and times. Then in this case to modify the TiO2, doping was done by transition metals and CdTiO3, CrTiO3, NiTiO3, MnTiO3, FeTiO3, and CoTiO3 were synthesized. The pure MTiO3 (M = Cd, Cr, Ni, Mn, Fe and Co) nanoparticles were formed when the precursor was heat-treated at 750 °C for 210 min. Characterizing the new additions was conducted by X-ray diffraction, FT-IR spectroscopy, UV–Vis spectroscopy, Scanning electron microscopy (SEM) image and N2 absorption–desorption. The BET analysis was performed to calculate the specific surface area. Pore diameter, pore volume, and the percentage of mesoporous MTiO3 were obtained by the BJH method according to the reaction. Titanium(IV) butoxide as a precursor was reacted with the metals and the energy band gap based on the metals decreased markedly and differently. To show the existing bond of titanium and metals, FT-IR and SEM image were used to investigate the obtained addition and investigating better their morphology respectively. To evaluate the photocatalytic properties of the nanocrystalline TiO2 (Degussa P-25) and MTiO3, the photocatalytic degradation of salicylic acid as a chemical toxic compound under ultraviolet light irradiation was carried out.

Photocatalytic degradation of salicylic acid with magnetic activated carbon-supported F-N codoped TiO2 under visible light

In this work, magnetically separable F-N co-doped TiO2 were synthesized using a facile sol-gel method grafted on magnetic activated carbon decorated with carbonized chitosan (F-N-TiO2/MAC-CTS). The composite photocatalysts were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), the N2 adsorption/desorption method (BET), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometry (VSM). The usage of hydrofluoric acid (HF) as F precursor could modify the morphology, crystalline size, specific surface area and energy bandgaps of the photocatalysts. Photocatalysts with different molar ratio of F:Ti turned out to show different photocatalytic ability for salicylic acid (SA). The highest degradation rate of 61.99% was achieved for samples with molar ratio (F:Ti) of 0.1 after 3 h visible light irradiation. The rate constant of F0.1-N-TiO2/MAC-CTS was 0.00532 min−1, which was about 2.5 times higher compared with photocatalyst doped with N only. Results of quenching experiment showed that ·OH and h+ played major roles in the photocatalysis. F0.1-N-TiO2/MAC-CTS still remained good photocatalytic activity after 4 times of recycling experiments.

Kinetic study of salicylic acid photocatalytic degradation using sol–gel anatase thin film with enhanced long-term activity

The scope of this work was to evaluate the photocatalytic degradation of salicylic acid (SA) using the anatase TiO2 thin film (hereafter: ATF) under UV-A irradiation and to explore the tentative long-term activity of ATF. The ATF was immobilized by the sol–gel procedure on the inner side of outer wall of annular glass reactor for maximized exposure area to applied irradiation. The ATF was used for 41 consecutive photocatalytic runs (trun = 60 min) and then irradiated under natural sunlight over a period of 15 days. Photocatalytic runs were repeated with irradiated catalyst, showing the unchanged photocatalytic activity with observed reaction rate constant k SA,obs = 4.0 × 10−7 min−1 W−0.5 m1.5. The degradation and mineralization kinetics of SA and the degradation by-products were studied. A tentative reaction scheme was presented. 2,5-Dihydroxybenzoic acid (2,5-DHBA) and 2,3-dihydroxybenzoic acid (2,3-DHBA) were identified as the main degradation by-products. The incident photon flux was determined along the inner reactor wall, i.e. on the thin film surface (I tf, W m−2) using two radiation emission models. To obtain kinetic parameters independently of photocatalyst optical properties and irradiation conditions, its lump value was introduced to kinetic model. A detailed kinetic study revealed first-order kinetics for SA, 2,5-DHBA, 2,3-DHBA and residual organics degradation and confirmed the preferred degradation pathway via ·OH radical attack.

Photocatalytic Degradation of Salicylic Acid and Reduction of Cr(VI) using TiO2

Photocatalytic Degradation of Salicylic Acid and Reduction of Cr(VI) using TiO2

Electrochemical assisted photocatalytic degradation of salicylic acid with highly ordered TiO2 nanotube electrodes

To explore the kinetics of photoelectrocatalytic degradation of salicylic acid, one of the important PPCPs, highly ordered TiO2 nanotube arrays (NTs) were prepared by the electrochemical anodization and characterized with scanning electron microscopy and X-ray diffraction techniques. The effect of TiO2 NTs properties, bias potential, initial salicylic acid concentration and solution pH on the degradation efficiency was studied and carefully analyzed. The results revealed that the salicylic acid degradation follows quasi-first order kinetics in the photoelectrocatalytic process, and the fastest decay kinetics was achieved in acidic environment (pH 2). The result was further interpreted through the electrochemical impedance spectroscopy. It is confirmed that the electrochemical assisted photocatalysis is a synergetic approach to combat stable organic substances with improved efficiency.

Preparation of polypyrrole–TiO2 and its adsorption and photocatalytic degradation of salicylic acid

Polypyrrole–TiO2 composited photocatalysts have been prepared by sol–gel method. The as-prepared photocatalysts were characterized by scanning electron microscopy, X-ray diffraction, and FT-IR. The results showed that the polypyrrole–TiO2 consists of well-defined hollow tubes with the size of inner diameter 0.5–1 μm, and the hollow tubes exhibited non-crystal phase and it was well-formed anatase phase at high temperature treatment. The performances of polypyrrole–TiO2 were tested by adsorption and degradation of salicylic acid. The adsorption equilibrium data, at different temperatures, were described by the Langmuir, Freundich, Temkin and Dubinin–Radushkevich isotherm models. The results showed that the Langmuir model was well fit to the equilibrium adsorption data, and the adsorption capacities could reach 32.4 mg g−1. The photocatalytic degradation activity of salicylic acid with polypyrrole–TiO2 was investigated under visible light irradiation. It was revealed that the degradation rate of salicylic acid with the polypyrrole–TiO2 which synthesized at 5°C without heat treatment could reach 48.6%. And the kinetics of photocatalytic degradation obeyed second-order kinetics.

Enhancing the photocatalytic degradation of salicylic acid by using molecular imprinted S-doped TiO2 under simulated solar light

Molecular imprinted polymer coated S-doped TiO2 (MIP/S-TiO2) nanocomposites were successfully synthesized by a surface molecular imprinting technique using p-phenylenediamine as the functional monomer and salicylic acid as the template molecule. The structure and properties of the catalysts were characterized by X-ray diffraction, scanning electron microscopy, and UV–vis diffuse reflectance spectra. Compared with TiO2 nanoparticles, the absorption edge of MIP/S-TiO2 nanocomposites was enhanced over the whole range of visible region. Moreover, MIP/S-TiO2 nanocomposites showed higher adsorption capacity for salicylic acid than for S-TiO2 nanoparticles. The rate constant for the photodegradation of salicylic acid over MIP/S-TiO2 nanocomposites was 1.7 times that of salicylic acid over S-TiO2 nanoparticles, which was attributed to the molecular recognition ability of MIP/S-TiO2 nanocomposites for the target molecules.

Enhanced Photocatalytic Degradation of Salicylic Acid in Water-ethanol Mixtures from Titanium Dioxide Grafted with Hexadecyltrichlorosilane

Abstract The aim of this paper is to study the effect of the chemical modification on the photocatalytic properties of TiO2. The TiO2 Degussa-P25 nanoparticles are chemically modified using the hydrophobic organosilane hexadecyltrichlorosilane (HTS). The samples are employed as catalysts for salicylic acid photocatalytic oxidation in water-ethanol mixtures. The kinetics of salicylic acid photodegradation is investigated as a function of ethanol content in water-ethanol mixtures and initial HTS concentrations. The results indicate that the HTS groups are not degraded during the photocatalytic process. The TiO2 grafted by HTS is more efficient than bare TiO2 for the photodegradation process in presence of ethanol. The photodegradation process follows first order kinetics and the apparent rate constant increases linearly with the initial HTS concentration (amount of HTS grafted).

Mass transfer measurements and modeling in a microchannel photocatalytic reactor

The main objective of this paper was to evaluate the influence of mass transfer on the photocatalytic efficiency at a low flow rate in the order of several mL per hour. Several continuous flow microchannel reactors have been used to study the degradation of salicylic acid (SA) taken as a model pollutant. The photocatalytic degradation of salicylic acid, under UV illumination of 1.5mWcm−2, was assessed from the outlet concentration measured by liquid chromatography HPLC. It was shown that the degradation of SA by UV was limited by mass transfer. Numerical simulations have allowed establishing a relationship of the Sherwood number valuable for all the microchannel geometries. Computational fluid dynamics with Comsol Multiphysics is useful for predicting the degradation yield for a given geometry of the microreactor. The best representation of the experimental data is obtained by introducing a kinetic law taking into account mass transfer limitation.

PHOTOCHEMICAL FABRICATION OF TRANSITION METAL NANOPARTICLES USING CdS TEMPLATE AND THEIR CO-CATALYSIS EFFECTS FOR TiO2 PHOTOCATALYSIS

Transition metal nanoparticles were prepared by chemical dissolution of CdS template from metal photodeposited CdS nanorod (length = 70–85 nm and width = 5–6 nm) heterocomposites. Size (9–10 nm) of metal nanoparticles obtained after CdS removal was larger than the size (4–6 nm) of metal nanodeposits over CdS template. The obtained Au nanoparticles displayed a broad red shifted absorption band at 660 nm, whereas Pt , Pd and Rh nanoparticles exhibit featureless absorption spectra. Elemental analysis confirms the complete removal of CdS template from Au – CdS ( Au — 2.65 at.%) and Ag – CdS ( Ag — 2.06 at.%) composites showing no Cd peak. These metal nanoparticles imparted dissimilar co-catalytic activity of TiO 2 for photocatalytic degradation of salicylic acid in the order Au > Pt > Pd > Ag > Rh as a function of their nature, electronegativity, redox potential and work function.

Photocatalytic Degradation of Phytotoxic Substances in Waste Nutrient Solution by Various Immobilized Levels of Nano-TiO2

The photocatalytic degradation effectiveness of six selected typical phytotoxic substances (ferulic, benzoic, gallic, salicylic, tannic, and acetic acid) by two levels of 10 nm TiO2 (11 and 22 g/m2) immobilized on tiles under 254 nm of UV light irradiation was investigated. The results showed that the immobilized nano-TiO2 significantly degraded all phytotoxic substances dissolved in distilled water, and the cumulative degradation rates of ferulic, benzoic, gallic, salicylic, tannic, and acetic acid reached 22.2, 33.6, 48.2, 56.9, 57.5, and 76.0 % after 6 h of treatment, respectively. Furthermore, the cumulative degradation rates of six phytotoxic substances by immobilized nano-TiO2 were different remarkably, i.e., salicylic acid > benzoic acid, gallic acid > ferulic acid, acetic acid > tannic acid. The maximal photocatalytic degradation efficiencies of all phytotoxic substances appeared at the first 2 h in the three experiments. During the 6-h treatment period, the photocatalytic degradation efficiency of all phytotoxic substances decreased gradually. There was no significant difference in the photocatalytic degradation of benzoic acid and ferulic acid between the two levels of immobilized nano-TiO2 treatments, whereas a significant difference was found in the photocatalytic degradation of salicylic acid, gallic acid, tannic acid, and acetic acid. In a word, nano-TiO2 photocatalysis is an effective method to degrade phytotoxic substances. And the photocatalytic degradation effectiveness of six typical phytotoxic substances may be related to their structures.