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The main objective of this study is to optimise a new composite for the depollution of contaminated water. This pollution can have adverse effects on both human health and the environment. The aim ...

Ibuprofen (IBP) is one of the most detected pharmaceuticals in wastewater. The conventional methods such as biological treatment, adsorption, etc. are ineffective and usually produce secondary pollution. In this contribution, FePO4 was synthesized using an inorganic sol-gel method assisted by microwave and used to remove IBP from water. X-ray diffraction (XRD), Thermal gravitational Analysis (TGA), Fourier transform infrared spectroscopy (FTIR), physisorption, Diffuse reflectance spectroscopy (DRS), X-ray photoelectron (XPS), and scanning electron microscopy (SEM-EDS) were used to study the phase structure, morphology, and optical properties of the synthesized FePO4. Moreover, for the first time, the photocatalytic property of the as-synthesized FePO4 compound has been evaluated via the degradation of Ibuprophen under artificial sunlight illumination. The findings indicated that FePO4 has a high activity under artificial sunlight irradiation, and the IBP removal was 97 % after 120 min.. Furthermore, the generation cycles indicated the higher stability of the photocatalyst to be effectively recycled up to four times without any considerable reduction in the photocatalytic performance. Finally, the involved mechanism of the photocatalytic performance of FePO4 was proposed based on the active species trapping experiments. Thus, It can be suggested that the FePO4 can serve as a promising photocatalyst in the degradation of IBP under sunlight illumination.

A novel arginine-modified Heliotrope leaf (Arg@HL) was used as adsorbent for the crystal violet (CV) dye adsorption in a batch process. The physicochemical and morphological composition of Arg@HL were characterized by field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The experiments were carried out to investigate the factors that influence the dye uptake by the adsorbent, such as the contact time under agitation, adsorbent amount, initial dye concentration, temperature and pH of dye solution. The optimum conditions of adsorption were found on the batch scale as followed: CV concentration of 20 mg·L−1, an amount of 0.75 g·L−1 of the adsorbent, 90 min contact time, 6 pH and 25 °C temperature for Arg@HL. The results confirmed a second-order model explaining the dye crystal violet's adsorption's kinetics by Arg-Heliotrope leaves. The Langmuir model effectively defines the adsorption isotherms. The results revealed that the Arg@HL has the potential to be used as a low-cost adsorbent for the removal of CV dye from aqueous solutions. HIGHLIGHTS The first effort to use a low-cost arginine-modified Heliotrope leaves material as an adsorbent for crystal dye elimination by adsorption procedures.; CV dye was efficiently removed using Arg@HL.; Arg@HL exhibited high adsorption capacity for CV dye.; Adsorption process follows the Langmuir isotherm.

α-Fe2O3 nanoparticles were synthesized via a straightforward method. XRD, FTIR, SEM, ESR, and DRS techniques investigated the influence of various calcination temperatures on the crystal structure, optical, and photocatalytic properties of the samples. The obtained results demonstrated that the average crystallite size increased with the increase in the calcination temperature. Measured and computed optical properties were in accordance and the bandgap energy decreased with the increase in the calcination temperature. The highest photocatalytic degradation efficiency for diclofenac (DCF) was obtained with the sample calcinated at 300 °C (96%). The photocatalytic process occurs because of the presence of OH• radicals. The addition of H2O2 led to the inhibition of OH• radicals that H2O2 scavenged.

Over more than three decades, the scientific community has been contentiously interested in structuring varying photocatalytic materials with unique properties for appropriate technology transfer. Most of the existing reported photocatalysts in the literature show pros and cons by considering the type of application and working conditions. Bismuth titanate oxides (BTO) are novel photocatalysts that raised recently towards energy and environmental-related applications. Most recent advances to developing bismuth titanate-based photocatalysts for the oxidation of organic pollutants in the water phase were reviewed in this report. To counter the potential drawbacks of BTO materials, i.e., rapid recombination of photoproduced charges, and further promote the photoactivity, most reported approaches were discussed, including creating direct Z-scheme junctions, conventional heterojunctions, metal/non-metal doping, coupling with carbon materials, surface modification and construction of oxygen vacancies. In the end, the review addresses the future trends for better engineering and application of BTO based photocatalysts towards the photodegradation of organic pollutants in water under controlled lab and large scales conditions.

Air pollution has become a significant challenge for both developing and developed nations. due to its close association with numerous fatal diseases such as cancer, respiratory, heart attack, and brain stroke. Over recent years, heterogeneous semiconductor photocatalysis has emerged as an effective approach to air remediation due to the ease of scale-up, ready application in the field, use of solar light and ready availability of a number of different effective photocatalysts. To date, most work in this area has been conducted using UV-absorbing photocatalysts, such as TiO2 and ZnO; However, recent studies have revealed Ag3PO4 as an attractive, visible-light-absorbing alternative, with a bandgap of 2.43 eV. In particular, this material has been shown to be an excellent photocatalyst for the removal of many types of pollutants in the gas phase. However, the widespread application of Ag3PO4 is restricted due to its tendency to undergo photoanodic corrosion and the poor reducing power of its photogenerated conductance band electrons, which are unable to reduce O2 to superoxide •O2 −. These limitations are critically evaluated in this review. In addition, recent studies on the modification of Ag3PO4 via combination with the conventional heterojunctions or Z-scheme junctions, as well as the photocatalytic mechanistic pathways for enhanced gas-pollutants removal, are summarized and discussed. Finally, an overview is given on the future developments that are required in order to overcome these challenges and so stimulate further research into this promising field.

In this work, the core–shell PANI@WO3 composite was obtained from the reaction of aniline monomer polymerization with WO3 particles; sodium persulfate was used as an oxidant. Various analytical techniques such as scanning electron microscopy (SEM-EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET), and X-ray photoelectron spectroscopy (XPS) were used to characterize the as-prepared PANI@WO3 adsorbent, which well confirmed that the WO3 particles were coated by polyaniline polymer. The PANI@WO3 composite was tested as an adsorbent to remove reactive orange G (OG) for the first time. pH, adsorbent dose, contact time, initial dye concentration, and temperature were systematically investigated in order to study their effect on the adsorption process. The experimental findings showed that the PANI@WO3 composite has considerable potential to remove an aqueous OG dye. Langmuir and Freundlich's models were used to analyze the equilibrium isotherms of OG dye adsorption on the PANI@WO3 composite. As a result, the best correlation of the experimental data was provided by the Langmuir model, and the maximum capacity of adsorption was 226.50 mg g 1. From a thermodynamic point of view, the OG dye adsorption process occurred spontaneously and endothermically. Importantly, PANI@WO3 still exhibited an excellent adsorption capability after four regeneration cycles, indicating the potential reusability of the PANI@WO3 composite. These results indicate that the as prepared PANI@WO3 composite could be employed as an efficient adsorbent and was much better than the parent material adsorption of OG dye

Mass spectrometers can provide information about molecular composition and chemical structure. However, with complex mixtures, superpositions and even suppression of signals may occur. On the other hand, Chromatography is an ideal technique for separating complexes but is often insufficient for compound identification. Hence, coupling both techniques in order to eliminate the limitations of each technique makes perfect sense. In this contribution, a brief description of mass spectrometry coupled with chromatography in the gas and liquid phase will be discussed to explain the advantages of coupling the two methods. The ionization techniques are also reported and followed by application areas of these techniques. Finally, the recording and treatment of the results are reviewed.

Photocatalytic degradation of Doxycycline in heterogeneous media constituted by nanoparticles of Fe2O3 and Fe2O3-Bi2WO6 was studied. The Bi2WO6 was prepared by hydrothermal method, and the Fe2O3-Bi2WO6 was obtained by mechanical mixing of Bi2WO6 to an amount of Fe2O3 and their photocatalytic activity to degrade doxycycline (Dox) under UV irradiation supported by H2O2 were studied. The H2O2 reacts with photogenerated electrons leading to the production of hydroxyl radicals (OH●). The Fe2O3 acts like a Fenton reagent, accelerating the production of OH●. In the present study Bi2WO6-Fe2O3/ H2O2 system demonstrate much higher photocatalytic efficiency to degrade Dox than pure Bi2WO6.

Herein, a novel PANI@Fe2O3@TiO2 (PANI@TF) composite containing different amounts of polyaniline was synthesized by in situ polymerization of aniline monomer in the presence of TF. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), BET surface area, Diffuse reflectance spectroscopy (DRS), X-ray photoelectron (XPS), and scanning electron microscopy (SEM-EDS) were used to study the phase structure, morphology, and optical properties of the synthesized PANI@TF composites. Moreover, for the first time, the photocatalytic property of the as-synthesized PANI@TF composites has been evaluated via the decolorization of MB under sun-like illumination. The findings confirmed that all the PANI@TF ternary composites with different PANI content showed enhanced visible-light photocatalytic activity for methylene blue (MB) dye degradation compared to pure Fe2O3@TiO2. The highest degradation efficiency for MB via 1% PANI@TF ternary catalyst reached 96% after 2 h under sun-like illumination, which was 4.3 higher than TF. Finally, a plausible photocatalytic mechanism for the improved photocatalytic activity was proposed to guide further improvement of its photocatalytic performance.

TiO2 nanoparticles of the single anatase phase, binary anatase–brookite phases, and ternary anatase–brookite–rutile phases were synthesized using an HNO3-catalyzed hydrothermal process. The types and amounts of phases varied depending on the hydrothermal synthesis conditions. The results revealed that N dissolves in different amounts and chemical states, depending on the phases present and their proportions in the nanoparticles. Brookite and rutile nanoparticles oriented through one direction were found to be crystallized by the surface transformation from anatase. Photocatalytic activity tests, evaluated by degradation of methylene blue (MB) under ultraviolet (UV) and visible light illumination, revealed that the N-doped TiO2 nanoparticles containing a ternary-phase mixture had the best photocatalytic activity. The MB degradation of the visible light–active nanoparticles was three times better than that of a commercially available well-known TiO2 powder, P25 under UV illumination. The enhanced photoactivity was attributed to the following: i) a high surface area, ii) suppression of the recombination of electron–hole pairs with ternary-phase mixture crystallized in heterojunctions, iii) larger anatase phase content, and iv) narrower band gap and facilitation of charge separation by dissolved N atoms.

International audience; A polyaniline@Fe-ZSM-5 composite was synthesized via an in situ interfacial polymerization procedure. The morphology, crystallinity, and structural features of the as-developed PANI@Fe-ZSM-5 composite were assessed using scanning electron microscopy – energy dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The composite was efficiently employed for the first time as an adsorbent to adsorb Orange G (OG) dyestuff from water. The OG dye adsorption performance was investigated as a function of several operating conditions. The kinetic study demonstrated that a pseudo-second-order model was appropriate to anticipate the OG adsorption process. The maximum adsorption capacity was found to be 217 mg/g. The adsorption equilibrium data at different temperatures were calculated via advanced statistical physics formalism. The entropy function indicated that the disorder of OG molecules improved at low concentrations and lessened at high concentrations. The free enthalpy and internal energy functions suggested that the OG adsorption was a spontaneous process and physisorption in nature. Regeneration investigation showed that the PANI@Fe-ZSM-5 could be effectively reused up to five cycles. The main results of this work provided a deep insight on the experimental study supported by advanced statistical physics prediction for the adsorption of Orange G dye onto the novel polyaniline@Fe-ZSM-5 hybrid composite. Additionally, the experimental and advanced statistical physics findings stated in this study may arouse research interest in the field of wastewater treatment.

This study investigates the degradation of imazapyr herbicide from wastewater by photocatalytic ozonation using TiO 2 as a semiconductor. Effects of operational parameters on imazapyr removal efficiency including TiO 2 dosing, initial herbicide concentration and pH were also studied. Obtained results showed that more than 90% of removal efficiency representing the disappearance of imazapyr was maintained until 7 µM in the presence of 200 mgL -1 of UV100-TiO 2 . Otherwise, the degradation of imazapyr followed the first-order kinetics with a photocatalytic rate constant of 0.247 min -1 , and complete degradation was achieved within 20 min using photocatalytic ozonation for 5µM of Imazapyr at pH 7.

The objective of this work is to correlate the photocatalytic degradation of the herbicide imazapyr in aqueous suspensions of the commercially available Evonik Aeroxide TiO2 P25 with the dark adsorption phenomena considering both the equilibrium state and the kinetics of adsorption. The results of this study show that the adsorption of imazapyr onto the TiO2 surface is a second-order reaction and satisfies the criteria required by the Langmuir model. The adsorbed amount of imazapyr is found to be high at pH 3 and to decrease with increasing pH. The kinetics of the photocatalytic degradation of imazapyr were analysed taking into account the effect of the pH as well as of the catalyst mass concentration. However, special attention was focussed on the influence of the reactant concentration on the reaction rate. The Langmuir–Hinshelwood model fitting revealed that the apparent adsorption constant obtained under irradiation is significantly larger than the adsorption constant obtained in the dark. The initial reaction rates of the photocatalytic imazapyr degradation were larger than the initial adsorption rates of the probe molecule on the TiO2 surface. It is therefore concluded that the photocatalytic imazapyr degradation does not follow necessarily a Langmuir–Hinshelwood mechanism despite the fact that a rate law having the mathematical form of the Langmuir–Hinshelwood rate law was successfully used to describe the observed dependence of the initial reaction rates on the initial concentrations. A Langmuir–Hinshelwood mechanism for the photocatalytic imazapyr degradation is compatible only with the additional assumption that the rate constant of adsorption increases by irradiation with UV light.

International audience; In the current study, an in-situ oxidative polymerization method was used to synthesize polyaniline-coated tungsten trioxide biphasic composite (PANI@WO3). The as-developed composite material properties were elucidated using different characterization tools such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), N2 sorption-desorption isotherm, and X-ray photoelectron spectroscopy (XPS). The PANI@WO3 was further applied to remove hexavalent chromium (Cr(VI)) from aqueous solutions. The results demonstrated that the optimal removal efficacy was achieved at pH 2. Meanwhile, the pseudo-second-order kinetic and isotherm of the Langmuir model were fitted for Cr(VI) adsorption. Cr(VI) amount of 549.37 mg·g−1 was the maximum capacity of adsorption attained for PANI@WO3, which is significantly higher than that of existing adsorbents. From a thermodynamic point of view, the Cr(VI) adsorption process occurred spontaneously and endothermically. Importantly, PANI@WO3 still exhibited an excellent adsorption capability after five regeneration cycles, indicating the potential reusability of the PANI@WO3 composite. XPS analysis of PANI@WO3 surface after adsorption of Cr(VI) confirmed its adsorption and concomitant reduction into Cr(III) ions. The transfer of mass phenomenon, electrostatic attraction, and reduction reaction were the primary processes for Cr(VI) ions elimination. These findings revealed that the synthesized PANI@WO3 exhibited a high potential for wastewater treatment containing Cr(VI).

Humankind is currently heavily reliant on fossil fuel for its energy supply. However, fossil fuels are a nonrenewable source. It requires hundreds of millions of years for fossil fuels to develop inside the earth, and with our daily rate of consumption, we will run out of fuel unless we find an alternative source. Solar energy has gained much attention as a solution for the current energy deficit since it converts light energy directly to electrical energy. Dye-sensitized solar cells deliver a cheaper and dependable alternative for numerous photovoltaic devices such as organic, inorganic, and hybrid solar cells. Dye-sensitized-solar-cell technology characteristically depends on photosensitizer (Dye), electrolyte, and the metal oxide semiconductor. This review paper enlightens the working principle, components, and development of DSSCs present development and future prospectus for this novel technology.

In this study, the synthesis of a novel arginine-functionalized polyaniline/FeOOH (Arg-PANI@FeOOH) composite for hazardous Hexavalent chromium ions (Cr(VI)) removal from wastewater was reported. The SEM, EDS, FTIR, XRD, and PZC measurements were used to characterize the as-developed Arg-PANI@FeOOH composite. Batch adsorption experiments were used to investigate the influence of pH, temperature, contact time, Arg-PANI@FeOOH amount, initial Cr(VI) concentration and coexisting ions on the efficiency of Cr(VI) removal. The Cr(VI) adsorption was much more advantageous at lower pH values, reflecting that the electrostatic interactions were the main driving forces that govern Cr(VI) binding mechanism on the Arg-PANI@FeOOH surface. The experimental data showed good fitness to the pseudo-second-order kinetics and Langmuir isotherm. The Cr(VI) species highest monolayer coverage capacity onto Arg-PANI@FeOOH was 682.30 mg g−1. The adsorption of Cr(VI) onto the Arg-PANI@FeOOH is spontaneous via an endothermic reaction. The competing anions were not affected the Cr(VI) adsorption, demonstrating that the Arg-PANI@FeOOH selectively adsorb Cr(VI) ions. The developed Arg-PANI@FeOOH material demonstrated good reusability up to five regeneration cycles. The process capability to predict the practical aptitude of Arg-PANI@FeOOH adsorbent to remove Cr(VI) from aqueous solutions was successfully applied. As a result, the adsorption of Cr(VI) onto Arg-PANI@FeOOH composite is a capable process for full-scale wastewater purification purposes. This paper provides relevant findings for a polyaniline-based adsorbent for the efficient removal of Cr(VI) from wastewater.

Mixed oxides, α-Fe2O3/Bi2WO6, were prepared using a mechanical mixing procedure by adding to the Bi2WO6 previously obtained by hydrothermal method the corresponding amount of a prepared α-Fe2O3, the latter obtained by thermal decomposition of Fe(NO3)∙9H2O. The physicochemical surface, structural, morphological characteristics and optical properties of the samples, single and mixed, were determined by BET, XRD, FE-SEM, XPS and UV–vis diffuse reflectance spectroscopy. UV–vis diffuse reflectance spectra showed that incorporating a 5%wt. of α-Fe2O3 to the corresponding amount of Bi2WO6 sample broadened the visible light absorption of Bi2WO6 as expected. The photocatalytic activity, of single and mixed catalysts, to degrade a selected dye such as Methyl Orange (MO) as well as the transparent substrate Phenol (Ph) was studied, in aqueous medium (pH ≈ 5.5) under UV and sun-like illumination conditions in the absence and presence of H2O2. In the present study the use of a α-Fe2O3-Bi2WO6/H2O2 system demonstrate much higher photocatalytic efficiency to degrade both MO and Ph than pristine Bi2WO6or α-Fe2O3, single or mixed. Using the system α-Fe2O3-Bi2WO6/H2O2, around 85% of MO was degraded in 60 min under sun-like illumination whereas 100% was degraded in 60 min under UV-illumination. However, just around 30% of Ph was degraded in 120 min in the α-Fe2O3-Bi2WO6/H2O2 system under sun-like illumination whereas around a 95% was degraded in 90 min under UV-illumination. Under UV-illumination, the generation of hydroxyl radicals is favorable; whereas under sun-like illumination, only the small fraction of the UV can produces the radical dotOH. Under illumination, the H2O2 could react with photoinduced electrons from the photocatalysts leading to the production of hydroxyl radicals (radical dotOH).

BaO-containing glasses of Bi2O–P2O5-V2O5 are synthesized by a conventional melt-quenching method. The as-prepared samples are first heat-treated at 350 °C overnight, and then heat-treated at 1000 °C for 30 min. The as-prepared samples are studied for their physicochemical properties using FTIR, SEM, and EDX analysis. A study of the as-prepared photocatalytic properties for the degradation of common organic dyes such as RhB under UV light is carried out. The highest rate of degradation (70%) is observed when a Bi(0.5-y)BayP(0.75-0.5y)V(0.75-0.5y)O4.5-3y catalyst with y = 0.1 was used. This sample maintains high photocatalytic activity after three cycles, without any significant decrease.

α-Fe2O3/TiO2 heterogeneous composites were synthesized by the sol-gel process to increase the photocatalytic activity of TiO2. The structural, morphological, and optical characteristics of the composites were determined by X-ray diffraction, scanning electron microscope, and UV–vis diffuse reflectance spectroscopy. Results revealed that the incorporation of α-Fe2O3 to TiO2 widened the visible light absorption ability of TiO2. It was realized that the calcination temperature plays a crucial role in morphology development hence photocatalytic activity of the α-Fe2O3/TiO2 heterogeneous composites. The photocatalytic activity of the composites calcined at various temperatures was evaluated for the degradation of Methylene Blue (MB) and Phenol (Ph) in aqueous medium under UV and sun-like illuminations. The α-Fe2O3-TiO2 composites exhibits superior photocatalytic efficiency to degrade both MB and Ph as compared to both pristine TiO2 and pristine α-Fe2O3 under sun-like illumination. The α-Fe2O3/TiO2 composite degraded approximately 90 % of MB and 50 % of Ph in 180 min sun-like illumination. Improvement in photocatalytic activity is attributed to the separation of photogenerated electron/hole pairs through the interaction of α-Fe2O3 and TiO2.

Humic acid (HA) and fulvic acid (FA) exist ubiquitously in environments and have a variety of functional groups, which allow them to complex with metal ions and pesticides. Furthermore, these interactions can not only alter the environmental behavior, but also influence the removal and transportation of those pollutants. The study of the interaction between Cu (II), VO (II) and Mn (II) with HAs provides environmental information on the oxidation states of paramagnetic metals and their mechanisms of binding to humic acids. Electron spin resonance (ESR) study demonstrates that VO (II) and Cu (II) ions are bound with oxygen ligands to HAs, while the Mn (II) complex occurs as [Mn(H2O)6]2+. Additionally, Cu (II) ions are more strongly bound than Mn (II) ions to soil HAs. The effect of the presence of HA on photolysis of Tribenuron-methyl (TRB) and Imazapyr (IMAZ) herbicides in water was studied by irradiation of different mixtures of HA/herbicide (0.5:1 and 1:1 by volume). The obtained results clearly demonstrate that HA substances exhibit a screening effect on the photochemical degradation of the two herbicides. The protective effect of HAs on the TRB and IMAZ degradation could be explained with an inclusion and/or adsorption of the herbicide molecules in the humic matrix., Moroccan Journal of Chemistry, Vol. 5, No 3 (2017)