The heterogeneous photocatalysis process has been known to provide significant levels of degradation and mineralization of emerging contaminants including antibiotics. For that, nanoparticle CuCr
2
O
...4
(CCO) ceramics were successfully prepared via sol-gel (SG) and co-precipitation (CP) methods to obtain spinel with desired structural features and properties and also to improve the photocatalytic performances. The CCO crystallite phase was produced at 750 °C all ceramics, disregarding the synthesis route. CCO physical and chemical properties were checked by X-ray diffraction (XRD) with Rietveld refinement, Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM), and diffuse reflectance solid (DRS). The XRD patterns demonstrated that the synthesized catalysts displayed a small crystallite size between 17.45 and 26.24 nm for SG and 20.97 and 36.86 nm for the CCO
CP
samples. The observation by SEM and TEM of the nanopowders showed a typical morphology with comparable particle sizes for both synthesized routes (20–30 nm). SG agglomeration rates were higher, and particles stick together more efficiently considering the CP method, while the CCO
CP
method led to a more significant porosity. Their photocatalytic and adsorption performances were examined for cefaclor (CFC) removal chosen as a target pharmaceutical contaminant in water. The results obtained by the methods differed since nanoparticles prepared by SG led to high photocatalytic activity. In contrast, a high CFC adsorption was observed for those prepared via the CP method, and that agreed with the findings of the characterization analysis. The kinetics of the adsorption process was found to follow the pseudo-second-order rate law. In contrast, the data of the photodegradation process were further found to comply with the Lagergren kinetic law. Nevertheless, the global reaction rate is probably controlled by the intra-particular diffusion of CFC, regardless of the elimination process.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The present contribution is to synthesize and characterize a new material photocatalyst. It also explores the possibility of using it to remove organic and inorganic pollutants in water. In this ...context, the sillenite Bi
12
CoO
20
(BCO) in pure phase was synthesized by the combustion sol–gel method. The phase was identified by X-ray diffraction (XRD) then it was refined in the cubic symmetry in the space group (I23 N°197) using the Rietveld refinement method; the lattice constant was accurately determined. A direct optical bandgap of 2.56 eV was evaluated using the UV–Visible diffuse reflectance. The electrochemical properties were investigated for the first time. A flat band potential of
E
fb
= 0.62 V
SCE
was found with a
p
-type character; the hole density
N
d
= 54.2 × 10
17
cm
−3
extends the depletion width at 27 nm. The photocatalytic activity of BCO nanoparticles was tested to eliminate organic and inorganic pollutants namely the Basic red 46 (BR46) and hexavalent chromium Cr(VI). An acceptable rate was observed within 3 h for both contaminants.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Zn-Fe layered double hydroxides was prepared by three methods of coprecipitation: coprecipitation at constant pH (pH Cst), coprecipitation at variable pH (pH Var), and direct coprecipitation (DC). ...The Zn-Fe LDH was utilized as an effective adsorbent for removal of cochineal red dye (CR) from aqueous solutions. The structure of the prepared materials was characterized by XRD and FTIR. The effects of various experimental parameters such as initial pH, adsorbent dosage, initial dye concentration, contact time, and temperature have been investigated using a batch adsorption technique and their optimum conditions were ascertained to find the optimal conditions for a maximum adsorption. At 50 mg/
l
cochineal red dye concentration and 50 mg of adsorbent mass, Zn-Fe LDH prepared by coprecipitation at constant pH had 1.09 and 1.31 times more adsorption capacity than Zn-Fe LDH prepared by direct coprecipitation and coprecipitation at variable pH, respectively. The adsorption capacity of the studied adsorbents was in the order pH Cst > DC > pH Var. The removal of Cochineal Red dye reaches its maximum of 96.74 %, 95.70 %, and 92.48 % after 40 min, 50 min, and 80 min for Zn-Fe LDH prepared by coprecipitation at constant pH, direct coprecipitation, and coprecipitation at variable pH respectively with the use of the optimum masses of 50 mg, 80 mg, and 100 mg for these respective materials. Freundlich and Temkin isotherm models were applied to describe the equilibrium adsorption experimental data. The cochineal red dye adsorption follows the Temkin model for the materials synthesized by coprecipitation at variable pH and direct coprecipitation. This indicates that the adsorption is characterized by a uniform distribution of binding energies between the molecules adsorbed and adsorbents. The Zn-Fe LDH prepared by coprecipitation at constant pH follows the Freundlich model, indicating the heterogeneous nature of adsorption sites. The adsorption kinetics of the dye obeyed pseudo-second-order kinetic model. Thermodynamic study indicates that the adsorption process is spontaneous and endothermic in nature.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
CoBi
2
O
4
(CBO) nanoparticles were synthesized by sol-gel method using polyvinylpyrrolidone (PVP) as a complexing reagent. For a single phase with the spinel structure, the formed gel was dried and ...calcined at four temperatures stages. Various methods were used to identify and characterize the obtained spinel, such as X-ray diffraction (XRD), scanning electron micrograph (SEM-EDX), transmission electron microscope (TEM), Fourier transform infrared (FT-IR), X-ray fluorescence (XRF), Raman, and UV-Vis spectroscopies. The photocatalytic activity of CBO was examined for the degradation of a pharmaceutical product cefixime (CFX). Furthermore, for the prediction of the CFX degradation rate, an artificial neural network model was used. The network was trained using the experimental data obtained at different pH with different CBO doses and initial CFX concentrations. To optimize the network, various algorithms and transfer functions for the hidden layer were tested. By calculating the mean square error (MSE), 13 neurons were found to be the optimal number of neurons and produced the highest coefficient of correlation
R
2
of 99.6%. The relative significance of the input variables was calculated, and the most impacting input was proved to be the initial CFX concentration. The effects of some scavenging agents were also studied. The results confirmed the dominant role of hydroxyl radical OH
•
in the degradation process. With the novel CoBi
2
O
4
/ZnO hetero-system, the photocatalytic performance has been enhanced, giving an 80% degradation yield of CFX (10 mg/L) at neutral pH in only 3 h.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This study explores efficient Sicomet Green (SG) dye degradation using Fe(III)/Lig and Fe(II)/Lig complexes in modified photo-Fenton processes under UV, LED, and sunlight. Sunlight irradiation showed ...rapid kinetics with over 70% degradation efficiency. Multi-objective grey wolf optimization achieved 98% degradation and 96% mineralization yield using Fe(III)/Lig without pH adjustment. Inorganic ions inhibited the modified photo-Fenton process. A user-friendly app aided predictions and optimal parameters selection, emphasizing natural light sources and pH-neutral medium for dye removal through photo-Fenton.
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•Efficient SG dye degradation with Fe(III)/Lig & Fe(II)/Lig under sunlight.•Sunlight irradiation yielded rapid kinetics (>70% degradation efficiency).•MOGWO optimization achieved 98% degradation, 96% mineralization without pH adjustment.•Inorganic ions inhibited modified photo-Fenton process performance.•User-friendly app for accurate predictions & optimal parameters.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this research work, removal of Cochineal Red A dye from aqueous solution was studied using layered double hydroxide materials prepared by a coprecipitation method at variable pH. The effects of ...the synthesis pH, the nature of the divalent cations and the total metal salt concentration on the formation of layered double hydroxides and their application to the removal of Cochineal Red A dye from aqueous solution were investigated. The structure of the materials prepared was characterized by X-ray diffraction and Fourier transform infrared. It was found that the nature and content of the bi- and trivalent metal ions in the layered double hydroxide influenced the adsorption. Ni–Fe had 0.96 to 1.70 times more adsorption capacity before reaching its equilibrium adsorption than Zn–Fe prepared at pH 7–9 with 2.2 M of total metal salt concentration. No difference was observed in the amount of Cochineal Red A dye adsorbed onto Zn–Fe prepared at both pH 7–9 and pH 10–11 in the range 1.1–3.3 M of total metal salt concentration. The results show that the increase in the precipitation pH leads to decreasing adsorption capacity. The Cochineal Red A dye adsorption follows the Temkin model for the Ni–Fe and Zn–Fe prepared at pH 7–9 and follows the Langmuir model for the Zn–Fe synthesized at pH 10–11 with high coefficient correlation. The adsorption kinetics data fitted the pseudo-second-order model. A thermodynamic study indicates that the adsorption process is both spontaneous and endothermic in nature.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Sillenite catalysts have shown efficient photocatalytic activity for the removal of various pollutants from water in previous studies, thus enhancing their activity by combining them with other ...materials will be very promising for environmental applications. In this context, an interesting hybrid system containing Polyaniline (PANI) as an adsorbent and Bi12TiO20 (BTO) sillenite as a catalyst was proposed in this work. Cefixime (CFX) has been selected as a pollutant for this study, and its removal was evaluated using PANI (adsorption), PANI and BTO (combined system) and the hybrid system Bi12TiO20/Polyaniline (BTO/PANI). First, the impact of PANI adsorption was investigated on its own; after that, the solution was filtered to separate the adsorbent from the liquid in order to re-treat the solution using photocatalysis (combining adsorption with photocatalysis). At the same time, a similar technique was used involving the hybrid system BTO/PANI. The results show that the hybrid system can remove a very high Cefixime concentration of 30 mg/L, almost 100%, within only 2 h, and this is better than previous investigations. These results indicate that it is possible to combine photocatalysis and adsorption processes to control water pollution.
This research attempted to synthesize a photocatalyst with a narrow bandgap and to investigate the possibility of using it to remove dyes from wastewater. The spinel CuCr
2
O
4
(CCO) was selected as ...a topical catalyst as it showed interesting proprieties in previous studies. The catalyst CCO has been synthesized using the sol–gel method and used to degrade Sunset Yellow (SY) in a stirred reactor. Before starting, the phase was identified by X-ray diffraction (XRD) and Fourier transform infrared (FTIR). Rietveld structure refinement (RSR) and the maximum entropy method (MEM) were used to derive accurate electron-density distributions of CCO from X-ray diffraction results, as well as to study the crystal and electronic structures. An orthorhombic structural phase with space group Fddd was observed for CCO. The morphology of this spinel was investigated using a scanning electron micrograph (SEM) and transmission electron microscope (TEM). The optical properties were measured using Diffusion reflectance spectroscopy (DRS) and an optical gap band of 0.9 eV was determined. After characterization, the photocatalytic activity of CCO was investigated for SY degradation. The effect of pH, catalyst dose and initial concentration (C
o
) on photocatalytic degradation was investigated. A degradation efficiency of 97% was achieved for 4 h under optimal conditions (pH 4, catalyst dose 0.8 g/L, C
o
10 ppm).
Highlights
The spinel CuCr
2
O
4
spinel has been synthesized by the sol–gel method.
An orthorhombic structural phase with space group Fddd was observed for CuCr
2
O
4
.
An optical bandgap of 0.9 eV was found for this semiconductor.
Efficient degradation of sunset yellow dye around 97% has been recorded using this catalyst.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This work aims to synthesize and characterize a material that can be used as an effective catalyst for photocatalytic application to remove both organic and inorganic compounds from wastewater. In ...this context, sillenite Bi12ZnO20 (BZO) in a pure phase was synthesized using the sol–gel method. Before calcination, differential scanning calorimetry (DSC) analysis was done to determine the temperature of the formation of the sillenite phase, which was found to be 800 °C. After calcination, the phase was identified by X-ray diffraction (XRD) and then refined using the Rietveld refinement technique. The results prove that BZO crystals have a cubic symmetry with the space group I23 (N°197); the lattice parameters of the structure were also determined. From the crystalline size, the surface area was estimated using the Brunauer-Emmett-Teller (BET) method, which was found to be 11.22 m2/g. The formation of sillenite was also checked using the Raman technique. The morphology of the crystals was visualized using electron scanning microscope (SEM) analysis. After that, the optical properties of BZO were investigated by diffuse reflectance spectroscopy (DRS) and photoluminescence (PL); an optical gap of 2.9 eV was found. In the final step, the photocatalytic activity of the BZO crystals was evaluated for the removal of inorganic and organic pollutants, namely hexavalent chromium Cr(VI) and Cefixime (CFX). An efficient removal rate was achieved for both contaminants within only 3 h, with a 94.34% degradation rate for CFX and a 77.19% reduction rate for Cr(VI). Additionally, a kinetic study was carried out using a first-order model, and the results showed that the kinetic properties are compatible with this model. According to these findings, we can conclude that the sillenite BZO can be used as an efficient photocatalyst for wastewater treatment by eliminating both organic and inorganic compounds.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
This work aims to synthesize a photocatalyst with high photocatalytic performances and explore the possibility of using it for antibiotic removal from wastewater. For that, the spinel ZnBi2O4 (ZBO) ...was produced with the co-precipitation method and its optical, dielectric, and electrochemical characteristics were studied. The phase has been determined and characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). For the ZBO morphology, a Scanning Electron Microscopy (SEM) has been used. Then, the optical and dielectric properties of ZBO have been evaluated by calculating refractive index n (λ), extinction coefficient (k), dissipation factor (tan δ), relaxation time (τ), and optical conductivity (σopt) using the spectral distribution of T(λ) and R(λ). An optical gap band of 2.8 eV was determined and confirmed. The electrochemical performance of ZBO was investigated and an n-type semiconductor with a flat band potential of 0.54 V_SCE was found. The photocatalytic efficiency of ZBO was investigated in order to degrade the antibiotic Cefixime (CFX) under different light source irradiations to exploit the optical properties. A high CFX degradation of approximately 89% was obtained under solar light (98 mW cm−2) only after 30 min, while 88% of CFX degradation efficiency has been reached after 2 h under UV irradiation (20 mW cm−2); this is in line with the finding of the optical characterizations. According to the obtained data, solar light assisted nanoparticle ZBO can be used successfully in wastewater to remove pharmaceutical products.
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