Acid Red Research Articles

Removal of Pb(Ii), Cd(Ii), Cu(Ii), Cr (Vi), Acid Red 1, Phenol and Toluene Using Carbon Sphere and Layered Double Hydroxide Composites

Removal of Pb(Ii), Cd(Ii), Cu(Ii), Cr (Vi), Acid Red 1, Phenol and Toluene Using Carbon Sphere and Layered Double Hydroxide Composites

Study of photo catalytical, antimicrobial activity, dielectric and ac impedance properties of Zn doped Mg nanoferrites synthesized from citrate gel auto combustion method

Mg–Zn nano ferrites with composition Mg(1-x)ZnxFe2O4 where x = 0.0 to 1.0 with 0.2 variation, were fabricated through citrate gel auto combustion method with step wise variation 0.2 mol%. UV–Visible spectroscopy confirmed the direct allowed transitions and optical band gap increased from 2.61ev to 2.71 with the addition of dopant Zn. The PL spectroscopy revealed that the broad near band edge emission in visible range 350–450 nm wavelength region. Antibacterial efficiency of the nano ferrites enhanced with the antibacterial dopant element Zn against gram positive Bacillus subtilis (MTCC 121) and gram negative Escherichia coli (MTCC 1687) strains. Organic dyes such as methylene blue and acid red were used to do photocatalytical degradation process and significant rate of degradation was found. Frequency dependent AC conductivity (σac) of the nano ferrites increased as a function of temperature and dopant Zn content. Dielectric parameters such as dielectric constant, dielectric loss (tan δ) were decreased with applied frequency. The results of dielectric studies reveals that the dielectric dispersion because of the hopping mechanism of electrons takes place in between Fe2+ and Fe3+ ions.

Enhanced photocatalytic degradation of toxic contaminants using Dy2O3-SiO2 ceramic nanostructured materials fabricated by a new, simple and rapid sonochemical approach

The present study is on the fabrication of new photocatalytic nanocomposites (Dy2O3-SiO2) employing a basic agent, tetraethylenepentamine (Tetrene), through a simple, efficient and, quick sonochemical approach. The features of the fabricated photocatalytic nanocomposite were examined employing a variety of microscopic and spectroscopic methods such as XRD, EDS, TEM, FTIR, DRS, and FESEM. The outcomes of morphological studies demonstrated that by proper tuning of sonication time and ultrasonic power (10 min and 400 W), a porous nanocomposite composed of sphere-shaped nanoparticles with a particle size in the range of 20 to 60 nm could be fabricated. The energy gap for the binary Dy2O3-SiO2 nanophotocatalyst was determined to be 3.41 eV, making these nanocomposite favorable for removing contaminants. The photocatalytic performance of the optimal nanocomposite sample was tested for photodecomposition of several contaminants including erythrosine, thymol blue, eriochrome black T, Acid Red 14, methyl orange, malachite green, and Rhodamine B. The binary Dy2O3-SiO2 nanophotocatalyst exhibited superior efficiency toward the decomposition of the studied contaminants. It was able to degrade the erythrosine pollutant more effectively (92.9%). Optimization studies for the photocatalytic decomposition of each contaminant demonstrated that the best performance could be achieved at a specific amount of contaminant and nanocatalyst. Trapping experiments illustrated that hydroxyl radicals were more effectively involved in the decomposition of contaminant molecules by Dy2O3-SiO2 nanophotocatalyst.

Functionalization of Zeolite NaP1 for Simultaneous Acid Red 18 and Cu(II) Removal.

The efficiency of azo dye Acid Red 18 (AR18) and Cu(II) ions simultaneous removal from an aqueous solution on NaP1CS and NaP1H was investigated, taking into account the effect of the phase contact time, pH, initial concentration, temperature, and interfering ions presence. Zeolite denoted as NaP1CS was modified by chitosan (CS) and zeolite denoted as NaP1H was modified by hexadecyltrimethylammonium bromide (HDTMA). In order to characterize sorption properties of NaP1CS, the obtained sorbent was characterized using Fourier transform infrared spectroscopy (FTIR) and nitrogen adsorption/desorption (ASAP). The kinetic parameters were determined by means of the pseudo first order (PFO), pseudo second order (PSO), and intraparticle diffusion (IPD) kinetic models. To present the adsorption data, three different isotherm models (Langmuir, Freundlich and Dubinin-Radushkevich) were used. The desorption process was also examined. It was found that for sorbent NaP1CS the pseudo second order (PSO) kinetic model and the Langmuir isotherm fitted best the experimental data. Moreover, it was noted that the acidic pH is appropriate to achieve the best sorption properties of NaP1CS for Cu(II) and NaP1H for AR18 and Cu(II). The thermodynamic parameters indicate an endothermic process. The most effective solution for the desorption process was found to be 1 M HCl. The results indicate that simultaneous removal of dye AR18 and Cu(II) on modified zeolite NaP1CS or NaP1H is possible and proceeds with a very good efficiency. The obtained zeolites could effectively adsorb AR18 an Cu(II) simultaneously, but their adsorption abilities were rather different.

Chitosan/lemon residues activated carbon efficiently removal of acid red 18 from aqueous solutions: batch study, isotherm and kinetics

ABSTRACT In this research, chitosan-decorated activated carbon (AC-CS) was proposed. The AC was cross-linked with glutaraldehyde to prepare an adsorbent (AC-CS). The AC-CS has a rough surface. Adding the AC-CS directly to the dye solution can achieve simple and convenient removal of anionic azo dyes acid red 18 (AR-18). In the dye solution, the AC-CS was used as an adsorbent. The effects of pH, contact time, temperature, initial concentration of AR-18 and the AC-CS dosage on the adsorption efficiency were investigated. Full kinetic and isotherm analyses were also undertaken. In addition, the reusability of the AC-CS was evaluated, and the results showed that the removal rate of AR18 after regeneration remained relatively stable, above 90%. This experiment has shown that AC-CS is a promising anionic azo dye adsorbent.

Pure and cerium-doped ZnO nanorods grown on reticulated Al2O3 substrate for photocatalytic degradation of Acid Red 88 azo dye

Pure and Ce-doped ZnO photocatalyst nanorods were both grown on α-Al2O3 ceramic foams manufactured using a polymeric sponge replication technique. A three-dimensional network of α- Al2O3 struts which served as the substrate for the photocatalyst material was first seeded via dip coating. The seed-mediated synthesis of ZnO nanorods with controlled lengths and diameters was then carried out at low temperature (∼95 °C) by chemical bath deposition (CBD). Their morphologies and crystallographic orientations were verified using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The effect of Ce-doping on the optical properties of the ZnO nanorods was investigated by ultraviolet–visible (UV–Vis) and photoluminescence (PL) spectroscopies. There was a modification in the band-gap structure with the incorporation of cerium atoms in the ZnO matrix as observed by the partial redshift at the absorption edges and by the blue and green light emissions. Color removal efficiencies of the samples were evaluated under UVA and visible light irradiations over the photocatalytic degradation of Acid Red 88 (AR88) azo dye molecules dissolved in water. Enhanced degradation rates were achieved for the Ce-doped samples compared to those of the pure ones. Similarly, the extend of mineralization (i.e., total organic carbon (TOC) removal) reached the maximum value of 54% for the Ce-doped samples under UVA light. According to the scavenging experiment results, it was found that the most effective radical involved in the present photocatalytic degradation reactions was the superoxide anion (·O2−).

CdTe quantum dots incorporated in CoNiAl layered double hydroxide interlayer spaces as a highly efficient visible light driven photocatalyst for degradation of an azo dye and Bisphenol A

The photocatalytic application of CdTe quantum dots (QDs) is restricted by the charge carriers recombination and tendency to aggregate in suspended systems. Novel functionalized CdTe (F-CdTe) QDs and CoNiAl layered double hydroxide (LDH) nanocomposite have been prepared to utilize the unique advantages of CdTe QDs. The nanocomposite is prepared via in situ synthesis of LDH in the presence of as-prepared F-CdTe QDs where the QDs partially intercalated in the interlayer spaces of LDHs. As a result of the effective electronic coupling between F-CdTe QDs and CoNiAl LDH, the light-harvesting ability has been enhanced and the absorption edge expands toward the higher visible light wavelengths. Moreover, the charge carriers recombination in nanocomposite has been considerably suppressed compared to the pristine CoNiAl LDH and F-CdTe QDs. Also, the nanocomposite shows remarkable enhancing in photocatalytic degradation of Acid Red 14 (AR14) and Bisphenol A (BPA) as the sample pollutants. The photogenerated holes and hydroxyl radicals have a determining role in the degradation of AR14. The plausible mechanism is proposed based on the experimental results and theoretical calculations. The prepared nanocomposite represents superior photocatalytic activity after 5 consecutive runs. So, the CdTe QDs can be effectively utilized in photocatalytic applications through the proposed promising approach.

Magnetic metal-organic framework (Fe3O4@ZIF-8) nanocomposites for adsorption of anionic dyes from wastewater

Since organic dyes are a major category of water contaminants, the processing of dye removal materials focuses on significant environmental significance. A metal organic structure adjusted by Fe3O4 nanoparticles (Fe3O4@MOF) has been easily synthesized and used as an adsorbent for the adsorption of Acid Red 57 (AR57) and Remazol Red (RR) anionic dyes and is used as a high-performance aqueous solution adsorbent. Fe3O4@ZIF-8, using a simple process, was synthesized at room temperature. The SEM, XRD, IR, and BET review described the Fe3O4@MOF as prepared. Fe3O4@MOF had a large specific area (475.3 m2/g), pore volume and pore size were also measured, X-ray diffraction spectroscopy (XRD), surface modification was measured using electron microscopy (SEM) scanning with a mean particle size of ∼248 nm in diameter, High chemical and thermal stability and high saturation magnetization (56.2 emu/g). Variables such as initial pH, adsorbent dosage, contact time and temperature have been studied in order to find optimal adsorption conditions for the extraction of Acid Red 57 (AR57) and Remazol Red (RR) from aqueous solutions. For the respective AR57 and RR, the optimal pH for extracting the anionic dyes tested from water solutions was 3 and 4. For AR57 and RR dyes, the overall predicted adsorption potential was 888.68 and 808.43 mgg−1, respectively, the effects of the initial solution pH, temperature, and, Initial concentration, contact time, salinity and dosing were systematically analyzed for Fe3O4@ZIF-8. These colors were ideal for acidic medium adsorption, where the zero-charge point (pHPZC) is equal to 4.3. The adsorption results were based on the isotherms of Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich adsorption. For both colors, the adsorption isotherm was found to obey the Lungmuir model. For AR57 and RR, the mean adsorption energy (Ea) is 20.24 and 31.3 kJmol−1, respectively, which indicates a phase of chemisorption. It was found that the kinetics of adsorption followed the pseudo-second-order kinetic model. The adsorption process was verified to be endothermic and random by thermodynamic experiments. The use of ethanol as the solvent was also studied in the method of desorption of the adsorbed anionic dyes.

Influence of interfacial, thermodynamic and hydrophobic parameters on Acid Red 57 removal by ionic micellar flocculation

ABSTRACT Most dyes are complex organic molecules that are highly resistant to degradation and may cause severe damage to live organisms and photosynthetic activities. In this respect, the aim of the present study was to assess the influence of interfacial, thermodynamic and hydrophobic parameters on Acid Red 57 removal from aqueous media by ionic micellar flocculation using surfactants sodium dodecanoate (C12), sodium tetradecanoate (C14) and sodium hexadecanoate (C16). The results demonstrate that an increase in the hydrophobic nature of the surfactant provokes different Krafft (Tkrafft) temperature and critical micelle concentration behaviors, and the greater the hydrophobicity the higher the solubilization temperature and lower the concentration needed for micelle formation. It was also found that long-chain surfactants cause an increase in the area of the polar part of the surfactant and change the micelle shape from lamellar (C12, C14) to cylindrical (C16), interfering in the solubilization capacity of the micelles. Micelle diameter determination aimed at demonstrating that the dye is solubilized inside the micelles via hydrophobic interactions. The dye removal tests showed that an increase in surfactant concentration improves process efficiency, surfactant C12 exhibiting the best dye removal indices (around 90%). Thermodynamic parameters showed that ionic micellar flocculation is exothermic and non-spontaneous.

Chromium (III) doped polycrystalline MgAl2O4 nanoparticles for photocatalytic and supercapacitor applications

A significant increase in demand for non-conventional energy sources has occurred recently. The most promising and dependent energy storage devices are supercapacitors. The mixed metal oxide MgAl2O4 has appreciable dielectric behavior but its application as an electroactive material is limited due to its low conductivity. In the present work, we demonstrated the exceptional supercapacitor application of doped MgAl2O4. Chromium (Cr3+)-doped (5 mol%) MgAl2O4 nanoparticles (NPs) were synthesized by solution combustion method. The morphological and structural features of the synthesized NPs were confirmed by the application of modern techniques. The Cr3+-doped MgAl2O4 NPs showed excellent photocatalytic activity against Acid Red-88 (AR-88) dye, with 89.2% degradation compared to 77.5% for undoped MgAl2O4. The electrochemical activity of Cr3+-doped MgAl2O4 NPs over the undoped counterpart was compared using cyclic voltammetric and electrochemical impedance spectroscopic measurements in an alkaline medium. The positive impact of Cr3+ on the conductivity and electrochemical activity of MgAl2O4 was evident with the attainment of higher specific capacitance value of 955.3 F g−1 at 1 A g−1 current density compared to 816.8 F g−1 for undoped MgAl2O4, and a high cycle life of over 2000 cycles. We report the superior electrochemical behavior of Cr3+-doped MgAl2O4 as anodic material for supercapacitor applications compared to undoped MgAl2O4. In addition, the synthesized Cr3+-doped MgAl2O4 NPs exhibited 89.2% degradation efficiency against AR-88.

Degradation of Acid Red 1 Catalyzed by Peroxidase Activity of Iron Oxide Nanoparticles and Detected by SERS.

Magnetic iron oxide nanoparticles (MIONPs) were synthesized using tannic acid and characterized by Raman, FTIR, UV, and DRX spectroscopy. In a heterogeneous Fenton-like reaction, the catalytic peroxidase-like activity of MIONPs in the degradation of Acid Red 1 (AR 1) dye was investigated. TEM/STEM was used to determine the quasi-spherical morphology and particle size (3.2 nm) of the synthesized MIONPs. The XRD powder patterns were indexed according to the reverse spinel structure of magnetite, and SEM-EDS analysis confirmed their chemical composition. At pH = 3.5, the decomposition of H2O2 in hydroxyl radicals by MIONPs results in high AR 1 degradation (99%). This behavior was attributed to the size and surface properties of the MIONPs. Finally, the Surface Enhanced Raman Spectroscopy (SERS) technique detected intermediary compounds in the degradation process.

Optical and Thermal Properties of Acid Red Doped Triglycine Acetate Crystal for Optoelectronic Applications

AbstractA positive change in crystal can be induced by dye. Pure and Acid Red 1 dye (AR) doped triglycine acetate (TGAc) single crystals are synthesized by solution approach to enrich the characteristics of pure TGAc crystals. The crystalline nature of the grown crystals is investigated using powder X‐ray diffraction. The Scherrer method has been used to calculate the crystallite size of both developed crystals and is compared to the Williamson and Hall method. Fourier transform infrared spectroscopy confirms the existence of several functional groups as well as dye inclusion in the produced crystals. Four distinct absorption bands are found in UV–vis–NIR absorption spectra at the location where AR dye is inserted into the TGAc matrix. Different optical constants, such as optical bandgap (Eg), extinction coefficient (k), refractive index (n) and optical conductivity (σ) are measured for both samples based on transmittance measurements. The thermal stability and decomposition temperature of 0.05 mol% AR dye doped TGAc are found to be higher. The doped crystals' improved optical characteristics and thermal stability prove their applicability for optoelectronic applications.

Electrochemical Sensing of Dextrose and Photocatalytic Activities by Nickel Ferrite Nanoparticles Synthesized by Probe Sonication Method

Background: Electrochemical sensing has been widely used as a glucose sensor. Methods: In the present work, we have investigated the application of nickel ferrite (NiFe2O4) nanoparticles (NFNPs) for dextrose sensing applications. NFNPS were synthesized by using a simple and low-cost probe sonication method (PSM). The structural, optical and electrochemical properties of prepared nanoparticles were measured by using XRD, FTIR and DRS techniques. Results: The PXRD pattern confirmed the formation of inverse spinel structure for NFNPs with a face-cente red cubic (FCC) structure. The diffuse reflectance spectral studies revealed the energy band gap of NFNPs as deduced to be 2.50 eV by using Kubelka-Munk function. The efficiencies in the photocatalytic degradation of Acid Red 88 (AR-88) and Acid Blue 88 (AB-88) dyes were found to be better with 93.45% and 84.45%, respectively. The EIS parameters corroborated the significant reduction in the charge transfer resistance of NFNPs electrode. The sensing of dextrose in acidic solution by using NFNP through carbon paste electrode was successful. Conclusion: The obtained sensing and photocatalytic results revealed that the synthesized NFNPs could be a better electrode material for the detection of dextrose with high electrode reversibility, in addition to its excellent photocatalytic characteristics towards the dye degradation.

Facile fabrication of AgFe1−xCuxO2 composite with abundant oxygen vacancies for boosted photocatalytic Cr (VI) reduction and organic pollutants degradation under visible light

In order to enhance the utilization of visible light and improve photocatalytic performance of AgFeO2, in this work, a novel copper (Cu) doped AgFeO2 composite catalysts with abundant oxygen vacancies (OVs) were synthesized by the co-precipitation method. The results of X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) showed Cu was successfully doped in AgFeO2 to form lattice defects, resulting in a large number of oxygen vacancies, which is beneficial for oxygen molecules to be activated into superoxide radicals. Compared with pure AgFeO2, the Cu doped samples expand the absorption region of visible light, thereby enhancing photocatalytic activity in the oxidization of organic pollutants and the reduction of Cr (VI). In a mixed Cr (VI)/ Acid Red G (ARG) solution, the 20 mg/L of ARG could be almost completely degraded within 90 min by Cu doped AgFeO2 composite, while the reduction efficiency of Cr (VI) is up to 90.19%, which is 1.95 times higher than that of AgFeO2. After the fourth photocatalytic recycling experiment, the photocatalytic performance of Cu doped AgFeO2 composite is still superior. The results of scavenger experiments show that holes (h+) and superoxide anions (O2•-) were the main dominant reactive for promoting photocatalytic reduction of Cr (VI) and degradation of organic pollutants over the Cu doped AgFeO2 composites. Based on the results of photoluminescence spectra (PL) and electron spin resonance (ESR), the enhanced photocatalytic performance of the Cu doped AgFeO2 could be contributed to oxygen vacancy caused by doping defects and the enhancement of visible light absorption.

Oxygen and methyl co-modified carbon nitride for enhanced photocatalytic dagradation

Carbon nitride (C3N4) is a promising photocatalytic material to degrade various pollutants. However, the degradation activity is restricted by the limited light absorption and fast recombination of photoinduced carriers. Herein, a structure modification strategy by introducing a functional reagent during the polymerization process was adopted. The structure, composition and morphology of prepared materials were investigated by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. Benefiting from the implantation of oxygen and methyl groups in triazine unit of C3N4, enhanced light absorption and effective carrier separation are achieved. As a result, the modified C3N4 exhibits a significant enhanced degradation activity and the optimal rate constant of modified C3N4 for Acid Red 9 degradation is 5.83 times that of pristine C3N4. The work demonstrates the effect of structure modification in C3N4 for enhancing degradation activity.

Microwave Assisted Reduction for Screening Banned Aromatic Amines in Azo Dyes

The study proposes a simple, novel and green alternative for the efficient reduction of azo dyes by the standard method, EN 14362-1:2012 (Annex. F) for detection of harmful aromatic amines in colorants, by incorporating microwave heating in place of convective heating. Basic dye response to reduction methods was explored by UV-visible spectroscopy and the results were confirmed through GC-MS and HPLC-DAD. Four azo dyes namely Acid red 1 (AR-1), Direct blue 15 (DB-15), Direct red 28 (DR-28) and Direct red 7 (DR-7) were reduced with sodium dithionite at 70 °C for 30 min in a buffered solution at pH 6.0, serving as a reference method. The decline in dye absorbance after their reduction was explored by UV-visible spectroscopy with carefully chosen bands of maximum absorbance from 300 to 700 nm. The alternative method exposed dye solutions to short microwave heating (10 s) and immediate cooling, in cycles till the desired duration of microwave heating was achieved. Results obtained from reference method were used for comparison with MAR (experimental method 1). Most prominent results of MAR were observed in the case of DR-28 dye. Hence DR-28 was further subjected to the conditions of experimental method 2, which was simply EN 14362-1:2012 (F) method modified with MAR. For standard method and experimental method 2, amines were analysed by GC-MS and HPLC-DAD. MAR methods were compared with reference and standard reduction methods for efficiencies. The total saving with MAR in terms of time and energy was ~70% and ~92% respectively.

Structural and optical properties of MgNb2O6 NPs: Its potential application in photocatalytic and pharmaceutical industries as sensor

Present research accounts for the production of columbite type MgNb2O6 nanoparticles (MNO NPs) by solution combustion method, its application in photocatalytic degradation and electrochemical sensor studies. The resultant nanoparticles were well characterized by Powder X-ray diffraction (PXRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and UV–Visible (UV–Vis) spectral studies. PXRD patterns showed that nanoparticles have orthorhombic phase with average crystallite size of ∼29 nm.The energy band gap of the sample was found to be 4.4 eV by Diffused reflectance spectroscopy (DRS) analysis. The MNO photocatalyst matrix influences excellent photocatalytic decolourization of Acid Red-88 (AR-88) and Fast orange red (FOR) dyes under UV light irradiation. The experiment show 86 % and 74 % dye decolourization respectively after 120 min irradiation. The holes (h+) are mainly responsible for excellent photocatalytic activities as confirmed by scavenger test. Electrochemical analysis was carried out to find the reversibility of the electrode reaction of electrode using 0.1 M KCl by Cyclic voltammetry (CV) and Electrochemical impedance spectroscopy (EIS) analysis. Thus, the prepared sample plays an excellent role in photocatalysis, electrochemical activity and chemical sensing applications.

CORRELATION STUDIES OF INDIGENOUS BIOFILM FORMING BACTERIA FOR RESISTANCE AGAINST SELECTED METALS, ANTIBIOTICS AND DYES DEGRADATION

This study determines correlation of biofilm-forming bacteria for selected metals, antibiotics and dyes. Total 12 strains having biofilm production potential were targeted in this study. Majority of them were Gram negative excluding MB377 and MB378, and facultative anaerobes. Isolates were mesophilic and exhibited growth capacity over a wide variety of pHs. Almost all isolates conferred resistance capacity against a wide range of multiple antibiotics having 0.0063 MAR for bacitracin, ampicillin, clindamycin, amoxicillin and sulphamethoxazole. Bacterial isolates displayed tolerance to diverse variety of metals i.e. cadmium, lead and iron 1000 mg L-1, copper 600-1000 mg L-1, chromium 700-1000 mg L-1 and nickel 200-600 mg L-1. Maximum heavy metal tolerance of 0.033 was observed for all metals excluding nickel. Correlation among metal tolerance and antibiotic resistance was extremely significant for chromium and bacitracin 0.862. Furthermore, moderate relationship (r= 0.682) between copper resistance and Basic Green 4 dye degradation was observed. Correlation coefficient for cadmium and Acid Red 2 dye was recorded as 0.512, while that for bacitracin and Basic Green 4 was noted as 0.665. These correlations proposed that resistance conferring genes might be present on same locus, genetic elements, chromosome or on a plasmid. 16S rRNA sequenced isolates were identified to be Klebsiella pneumoniae MB375, Staphylococcus sp. MB377, Klebsiella oxytoca MB381, Klebsiella pneumoniae MB394 and Klebsiella pneumoniae MB398. Potential of these biofilm forming strains to thrive under stressed environmental conditions proves them good entrants for being used in bioremoval of polluted sites after further studies on their metabolic pathways.

Theoretical analysis of the removal mechanism of Crystal Violet and Acid Red 97 dyes on Agaricus bisporus residue

In this paper, the Agaricus bisporus residue (ABR) is employed as an adsorbent to study the adsorption mechanism of two relevant dyes, namely Crystal Violet (CV) and Acid Red 97 (AR97). The adsorption mechanism is theoretically analyzed by application of models derived from statistical physics and the model parameters derived from the best fitting are used for the interpretation of the experimental results. A double-layer model best fitsboth CV and AR97 experimental data,showing that AR97 molecules aggregate only at high temperature forming a dimer (n = 2.55 at T = 328 K). Similarly, CV dye tends to form a monomer with a slight tendency to a dimer at high temperature.AR97 dye is adsorbed through a non-parallel orientation on the ABR surface at most of the investigated temperatures (T = 298, 318 and 328 K), while CV dye is removed via both parallel and non-parallel orientations. The analysis of the adsorption capacity suggests that ABR adsorbent has a stronger affinity to remove AR97. The calculation of the adsorption energies indicated that the adsorption process is a physisorption.

Photocatalytic activity enhancement of carbon‐doped g‐C3N4 by synthesis of nanocomposite with Ag2O and α‐Fe2O3

AbstractCarbon‐doped g‐C3N4 (CGNS) nanocomposite with Ag2O and α‐Fe2O3 has been synthesized to improve g‐C3N4 photocatalytic activity. The prepared CGNS/Ag2O/α‐Fe2O3 (GAF [with mass ratio 3:2:1]) nanocomposite exhibits the expanded visible‐light absorption region leading to the enhanced photocatalytic performance for Acid Red 14 (AR14) degradation. Besides, it is found that the recombination rate of the charge carriers effectively suppresses the nanocomposite. For a better understanding of the photocatalytic degradation mechanism, the reactions have been performed in the presence of different scavengers. The experiments indicate that superoxide anion radicals possess a more influential role in AR14 degradation in comparison with hydroxyl radicals and holes. The degradation efficiency has been decreased from 94.68 to 85.60 after five consecutive photocatalytic tests implying that the prepared nanocomposite is a stable photocatalyst. In the end, the kinetic study of AR14 degradation on nanocomposite with considering pseudo‐first‐order kinetics results in a nonlinear empirical kinetic model development for prediction of degradation efficiency of AR14 on nanocomposite.