Auramine Research Articles

One pot green synthesis of Al doped zinc ferrite nanoparticle decorated with reduced graphene oxide for photocatalytic remediation of organic pollutants: Green synthesis, kinetics, and photoactivity

The world is drawn to the widespread use, toxicity, and bioaccumulation of the Atrazine (AT) and Auramine O (AO). Pesticides and dyes also have endocrine disruptors, genotoxic and persistent properties. Therefore, the photodegradation of AT and AO in water was investigated. Herein, the structural design of Al–ZnFe2O4 incorporated in rGO nanocomposite has been synthesized via facile precipitation and green synthesis methodology. PXRD and microscopic analysis confirmed the reduced crystallinity nature of Al–ZnFe2O4 due to the incorporation of amorphous rGO. The green Al–ZnFe2O4@rGO nanocomposite (AT: 90%; AO: 95%) showed maximum degradation as compared to native nanoparticles with minimum pollutants concentration of 10 mg catalytic dose at neutral pH in sunlight irradiation due to negative zeta potential (−36.0 mV), higher surface area (163 m2g-1) and tailored band gap (2.1 eV). First-order kinetics followed by initial Langmuir adsorption constituted the degradation process. The presence of different radical quenchers (t-BuOH, p-BZQ, Na2EDTA) concluded that hydroxyl radical plays a significant role in the degradation of toxic AT and AO. Green fabricated Al–ZnFe2O4@rGO also showed excellent efficiency for the degradation of AT and AO pollutant in real wastewater sample. Nanocomposite demonstrated remarkable sustainability and cost-effectiveness by remaining effective for up to nine cycles without experiencing any appreciable activity reduction. Due to its favorable surface features, Al–ZnFe2O4@rGO nanocomposite made via green process is a unique and potential photocatalyst for industrial applications.

Synthesis and Characterization of Phosphorus-Containing Sorbent for Basic Dye Removal.

A new phosphorus-containing sorbent was prepared by copolymerizing ethylene glycol dimethacrylate (EGDMA) and trimethylvinyl silane (TMVS) with diphenylvinylphoshine oxide (DPVO). It was characterized and applied in the removal of cationic dyes such as C.I. Basic Yellow 2 (BY2), C.I. Basic Blue 3 (BB3) and C.I. Basic Red 46 (BR46) using the batch method. Spectroscopic analysis indicated that the phosphinoyl group was introduced into the sorbent structure. Equilibrium adsorption data were fitted to the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. The Freundlich model is the most suitable to describe the adsorption of BB3 (the Freundlich constant kF = 32.3 mg1-1/nL1/n/g) and BY2 on the sorbent (13.8 mg1-1/nL1/n/g), while the Langmuir model is the most adequate to describe the adsorption of BR46 (the monolayer capacity Q0 = 2.7 mg/g). The kinetics of the dye adsorption follows the assumptions of the pseudo-second-order (the rate constants k2 = 0.087 ÷ 0.738 g/mg min) model rather than pseudo-first-order or intraparticle diffusion. The presence of Na2SO4 and cationic surfactant in the aqueous solutions inhibited dye retention by the DPVO-EGDMA-TMVS. Adsorbent regeneration efficiency does not exceed 60% using 1 M NaCl and 1 M HCl solutions in the presence of 50% v/v methanol.

Adsorption of Basic Yellow 28 and Basic Blue 3 Dyes from Aqueous Solution Using Silybum Marianum Stem as a Low-Cost Adsorbent.

In the present study, the ability of an adsorbent (SLM Stem) obtained from the stem of the Silybum Marianum plant to treat wastewater containing the cationic dyes basic blue 3 (BB3) and basic yellow 28 (BY28) from aqueous solutions was investigated using a batch method. Then, the SLM Stem (SLM Stem-Natural) adsorbent was carbonized at different temperatures (200-900 °C) and the removal capacity of the products obtained for both dyes was examined again. The investigation continued with the product carbonized at 800 °C (SLM Stem-800 °C), the adsorbent with the highest removal capacity. The dyestuff removal studies were continued with the SLM Stem-Natural and SLM Stem-800 °C adsorbents because they had the highest removal values. The surface properties of these two adsorbents were investigated using IR, SEM, and XRD measurements. It was determined that the SLM Stem-Natural has mainly non-porous material, and the SLM Stem-800 °C has a microporous structure. The optimal values for various parameters, including adsorbent amount, initial dye solution concentration, contact time, temperature, pH, and agitation speed, were investigated for BY28 dye and were 0.05 g, 15 mg/L, 30 min, 40 °C, pH 6 and 100 rpm when SLM Stem-Natural adsorbent was used and, 0.15 g, 30 mg/L, 30 min, 40 °C, pH 10, and 150 rpm when SLM Stem-800 °C adsorbent was used. For BB3 dye, optimal parameter values of 0.20 g, 10 mg/L, 30 min, 25 °C, pH 7, and 100 rpm were obtained when SLM Stem-Natural adsorbent was used and 0.15 g, 15 mg/L, 40 min, 40 °C, pH 10, and 100 rpm when SLM Stem-800 °C adsorbent was used. The Langmuir isotherm described the adsorption process best, with a value of r2 = 0.9987. When SLM Stem-800 °C adsorbent was used for BY28 dye at 25 °C, the highest qm value in the Langmuir isotherm was 271.73 mg/g. When the study was repeated with actual water samples under optimum conditions, the highest removal for the BY28 dye was 99.9% in tap water with the SLM Stem-800 °C adsorbent. Furthermore, the reuse study showed the adsorbent's efficiency even after three repetitions.

Sunlight assisted highly efficient photocatalytic remediation of organic pollutants by green biosynthesized ZnO@WO3 nanocomposite

The widespread use of toxic plastic additives in the plastics industry and dyes in various sectors has drawn scientific attention since their ability to leak from consumer goods raises environmental concerns. Plastic additives and dyes also have endocrine disruptor, genotoxic, and persistent properties that have been demonstrated. Herein, photodegradation of bisphenol A (BPA) and Auramine O (AO) in water was investigated. Herin, the structural design of ZnO doped WO3 nanocomposite has been synthesized via facile precipitation and green synthesis methodology. Sharp PXRD peaks ensured that the spherical nanocomposite had great crystallinity and purity. XPS analysis, PXRD, and FE-SEM confirmed the effective doping of ZnO with WO3. Subsequently, ZnO@WO3 nanocatalyst was evaluated for the effective elimination of BPA and AO at variable reaction parameters (pollutant: 5–25 mgL−1; catalyst: 5–25 mg; pH: 5–9, dark-sunlight-artificial bulb). At neutral pH and in sunlight, ZnO@WO3 demonstrated maximal degradation of 5 mgL−1 of BPA (91%) and AO (96%) at a catalytic dosage of 15 mg. The yellow color of AO decolorized within 3 h, confirming the effective removal of AO. First-order kinetics followed by initial Langmuir adsorption constituted the degradation process. The presence of different radical quenchers (t-BuOH, p-BZQ, Na2EDTA) concluded that hydroxyl radical plays a significant role in the degradation of toxic BPA and AO—formation of safer metabolites after degradation of BPA and AO confirmed by LC-MS analysis. The efficiency of green fabricated ZnO@WO3 was also investigated in actual wastewater samples to remove BPA and AO. Nanocomposite demonstrated remarkable sustainability and cost-effectiveness by remaining effective for up to eight cycles without experiencing any appreciable activity reduction. A potential and different photocatalyst for industrial applications, green synthesized ZnO@WO3 nanocomposite has good surface properties.

Effect of indium (III) doping on Ag3PO4 catalyst stabilization and its visible light photocatalytic activity toward toxic dyes in water.

Indium(III)-doped Ag3PO4 (In-AgP) catalysts at different weight percentages were elaborated by co-precipitation and subjected to XRD, SEM, UV-vis DRS, and FTIR characterization. The prepared catalysts were of spherical morphology and their diameters depends on doping dosage. The whole materials crystallize in a centered cubic system with a slight dissimilation in the positions of the characteristic peaks as a function of indium dosage. The photocatalytic performance of the catalysts under visible light was investigated in the photocatalytic degradation of anionic dye (methyl orange (MO)) and cationic dye (auramine O (AO)) in moderate acid, neutral, and basic pH conditions. Results showed more selectivity to MO than AO. Furthermore, indium-doped samples are more active in the acidic medium than the pure Ag3PO4 (AgP), and 10%In-AgP catalyst presents the highest activity. The degradation efficiency reached 99 % in 60 min for MO and in 180 min for AO. In addition, a high recycling stability was achieved and the catalyst retains its degradation capacity above 99 % after five cycles.

Investigation of Effective Removal of Auramine O Dye by Pyracantha Coccinea Biosorbent: Isotherm and Kinetics

In this study, the effect of biosorbent dosage (0.1-0.4 g/L), dye pH (3.0-9.0) and initial dye concentration (50-500 mg/L) on synthetic Auramine O (AU-O) dye removal of biosorbent produced from Pyracantha coccinea (PC) plant by physical modification was investigated and the dye removal behavior of the biosorbent was investigated by kinetic and isotherm experiments. In the batch experiments, it was observed that as the adsorbent quantity was raised from 1 g/L to 4 g/L at a consistent dye concentration, the adsorption capacity declined from 69.25 mg/g to 22.73 mg/g. The adsorption capacities of AU-O dye at concentrations of 50 mg/L and 100 mg/L were determined to be 22.350 mg/g and 72.35 mg/g at 200 mg/L, respectively. The reason why there was no significant increase in adsorption capacity at higher dye concentrations (250-500 mg/L) was that at constant amount of biosorbent, the change in adsorption capacity was minimal since the active sites of the biosorbent reached saturation. The adsorption capacity was determined to be 26.512 mg/g, 38.74 mg/g, and 44.07 mg/g at pH:3.0, pH:4.88, and pH:7.0, respectively. It has been determined that the adsorption capacity achieved at pH 9.0 (44.21 mg/g) was nearly equivalent to the adsorption capacity observed under neutral pH conditions. The adsorption mechanism is best explained by the Langmuir isotherm (qm:123.10 mg/g and R2:0.990) and the pseudo-second-order kinetic models (R2: 0.985) in the adsorption isotherm and kinetic research.

Biodegradable tamarind kernel powder/kappa-carrageenan hydrogel for efficient removal of cationic dyes from effluents.

As an adsorbent for wastewater treatment, an eco-friendly biodegradable hydrogel was utilized in an effort to reduce the hydrogel production costs and decrease its negative impact on the environment. The biodegradable hydrogel of natural polysaccharides, tamarind kernel powder (tkp) with kappa-carrageenan (kcg), was employed as an adsorbent to remove cationic dyes from an aqueous environment. The impact of factors such as initial adsorbate concentration, pH, contact time, temperature, and adsorbent dosage on maximum adsorption were investigated. The tkp-kcg hydrogel has a remarkable swelling percentage of 1840%. The high water penetration of the tkp-kcg hydrogel made the internal adsorption sites for safranin (SF) and auramine-O (AO) dye adsorption accessible. The correlation coefficient supported the Langmuir isotherm model's applicability, with maximum adsorption efficiency of 9.372 mg g-1 for SF and 9.225 mg g-1 for AO. The kinetics of adsorption revealed a pseudo-second order process. Adsorption was an exothermic and spontaneous, according to thermodynamic analyses. Furthermore, the adsorbent was effectively used for five consecutive cycles of SF and AO dye adsorption-desorption. The biodegradation of tkp-kcg hydrogel was characterized by percentage of weight loss, Fourier transform infrared and scanning electron microscopy techniques. The composting technique of biodegradation was used in the biodegradation studies. Using the composting process, 92.6% of the synthesized hydrogel was degraded after 70 days. The results demonstrated that the hydrogel has a high microbiological biodegradability. It is believed that the tkp-kcg hydrogel could have excellent wastewater and agricultural applications due to its high water absorption, excellent retention capacities, cost-effective and ecofriendly synthesis. PRACTITIONER POINTS: Microwave assisted tkp-kcg hydrogel was synthesized with the swelling percentage of 1840%. Synthesized hydrogel showed excellent cationic dyes (SF and AO) adsorption capacity with a good recyclability. The synthesized hydrogel showed very good biodegradability of 92.6 % in 70 days by using composite method.

Bazı Azo Boyalarının QSAR Yöntemi ve Daphnia Magna ile Akut Toksisite Testi ile İncelenmesi

Azo dyes represent the most important class of textile dyes. Biotransformation of azo dyes can release aromatic amines. It is well known that some aromatic amines have genotoxic and/or carcinogenic properties. In this study, it was aimed to investigate the effects of azo dyes, which are composed of aromatic amines, and are widely used in the textile industry, on the environment using acute water toxicity test. The acute water toxicity test using Daphnia Magna was investigated experimentally and theoretically. The OECD QSAR Toolbox program, which has recently attracted attention in theoretical studies and is also used in international regulations, has been preferred. As a result of the studies, it was seen that the experimental and theoretical results gave parallel results. This study showed that theoretical studies can be substituted for experimental studies in order to reduce cost, time, and animal mortality in acute toxicity tests on Daphnia Magna. In addition, according to the results of this study, it was found by experimental and theoretical methods that Basic Yellow 28, Disperse Blue 291, and Disperse Brown 27-1 azo dye are ecotoxicologically toxic.

Modelling of Basic Yellow 28 adsorption onto activated carbon: batch and continuous process

Purpose This study aims to model and investigate Basic Yellow 28 (BY28) adsorption onto activated carbon in batch and continuous process. Design/methodology/approach Batch adsorption experiments were carried out at 25 °C with 50 mg/L BY28 solution at pH 6 with different amounts of activated carbon. Freundlich and Langmuir adsorption isotherm models were used to model batch data. Pseudo-first-order and pseudo-second-order kinetic models were applied with linear regression. The changes of the breakthrough curve with the column height, flow rate, column diameter and adsorbent amount were examined in fixed bed column at room temperature. BY28 adsorption data were modelled by using different adsorption column models (Adams & Bohart, Thomas, Yoon & Nelson, Clark and modified dose–response) with non-linear regression. Findings Freundlich model and pseudo-second-order kinetic model expressed the experimental data with high compatibility. Modified dose-response model corresponded to the fixed bed column data very well. Originality/value Adsorption of Basic Yellow 28 on activated carbon in a fixed bed column was studied for the first time. Continuous adsorption process was modelled with theoretical adsorption models using non-linear regression.

Analysis of 13 Banned Colorants in Cosmetics via Liquid Chromatographic and Mass Spectrometric Techniques

Even though synthetic colorants can cause side effects such as allergies and pigmentation, they have not been sufficiently researched. Herein, high-performance liquid chromatography, liquid chromatography-tandem mass spectrometry, and liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) were used to detect 13 banned synthetic colorants in cosmetics and characterize their fragmentation. The developed HPLC method was validated following the International Conference on Harmonisation guidelines (specificity, limit of detection, limit of quantification, recovery, linearity, accuracy, and precision) and applied to 120 distributed cosmetic products, one of which was found to contain three illegal synthetic colorants, namely Basic Blue 26 (0.33 mg/g), Basic Red 2 (0.53 mg/g), and Basic Yellow 28 (31.50 mg/g). Additionally, based on their fragment ions obtained using LC-Q-TOF-MS, the fragmentation pattern of synthetic colorants was predicted. Thus, our work paves the way for the reliable detection of illegal synthetic colorants and may help to prevent the distribution of cosmetics containing the same.

Magnesium ferrite as a dispersive solid-phase extraction sorbent for the determination of organic pollutants using spectrophotometry

This study aimed to determine of malachite green (MG) and auramine O (AO) dyes in different environmental water samples. For this purpose, MG and AO dyes were pre-concentrated by ultrasound-assisted dispersive solid-phase extraction (UA-DSPE) and measured by spectrophotometry. Magnesium ferrite (MgFO) was applied as a magnetic adsorbent in the UA-DSPE-UV/Vis method. The effect of different parameters on the dye extraction efficiency, including pH of the solution, sorbent mass, sample volume, ultrasound frequencies, irradiation time, and type and volume of eluent, were investigated. In addition, response surface methodology (RSM) approach-based central composite design (CCD) was used to design and optimize parameters affecting the process. Analysis of variance (ANOVA) results based on high F-values, low p-values, coefficient of determination (R2 > 0.99), and adjusted-R2 (R2adj > 0.99) revealed that the quadratic model was the best model for defining the interaction of the studied variables. The calibration curve, the limit of detection (LOD), and relative standard deviation (RSD, n = 5) for MG and AO dyes were 1–800 ng mL−1 and 3–1200 ng mL−1, 0.33 ng mL−1 and 1 ng mL−1, and 3.2% and 2.8%, respectively. The effect of some external species (including cations and anions) on the determination of MG and AO dye was investigated. The results revealed that adding different ions does not significantly interfere with determining MG and AO dyes. The reusability of the MgFO adsorbent showed that it could be reused for up to 7 cycles, maintaining its high efficiency in the extraction of MG and AO dyes. Moreover, the proposed method was used for the extraction of MG and AO dyes from different water samples. The obtained extraction efficiency was in the range of 95.37–99.54%.

Effective removal of cationic dyes from aqueous solutions by using black cumin (Nigella sativa) seed pulp and biochar

Black cumin seed pulp (C), as well as biochar (CC) produced via pyrolysis of black cumin seed pulp were used to remove methylene violet 2B (MV) and basic yellow 28 (BY28) from aqueous solution. Adsorption isotherms and kinetics were applied at 10, 25, and 35 °C. The adsorption of methylene violet 2B and basic yellow 28 on the black cumin seed pulp and biochar surface was exothermic; the heat of adsorption values were lower than 0. The adsorption capacities of BY28-C, BY28-CC, MV-C, and MV-CC were 212.8, 625, 164, and 909 mg g-1 at 25 °C, respectively. The adsorption of black cumin seed pulp and biochar data were examined with the Freundlich, Langmuir, Temkin, Dubinin-Radushkevich (D-R), and Flory-Huggins (F-H) isotherm models. The kinetics of the adsorption were fitted to the pseudo first-order and pseudo second order equations. The pseudo second order equation gave a better fit than the pseudo first-order equation.

Amazon raw clay as a precursor of a clay-based adsorbent: experimental study and DFT analysis for the adsorption of Basic Yellow 2 dye.

A clay-based adsorbent (CBA) was purified from a sustainable precursor (raw clay, RC), which was obtained from the Amazon region in Brazil. The CBA was characterized using X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Brunauer-Emmet-Teller surface area (SBET, RC = 23.386 m2.g-1, CBA = 33.020 m2.g-1), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), thermogravimetric analysis (TGA), cation exchange capacity (CEC, CBA = 44.75 cmol/kg), and point of zero charge analyses (pHPZC, CBA = 2.20). Subsequently, CBA was used to adsorb basic yellow 2 (BY2) dye from aqueous solutions. A CBA dosage (1g/L), initial concentration of dye (C0 = 15mg/L), and pH (5.6) were ideal conditions for the BY2 dye removal of ~ 98%. The BY2 kinetics was better represented by the pseudo-first-order (PFO) model while the BY2 equilibrium was well represented by the Sips model, with a maximum adsorption capacity of qms = 18.04mg/g at 28°C. The negative values of ΔG° and ΔH° showed that the studied process is spontaneous and exothermic, while the values of isosteric heat (∆Hst, -16 to -20kJ/mol) suggest a predominance of physical interactions. The molecular chemical reactivity of BY2 was investigated using quantum chemical descriptors calculated based on Density Functional Theory (DFT) optimization of the dye molecule, and the results revealed a large energy gap value (4.3900eV) and considerable chemical hardness (η = 2.1950eV). Therefore, the correlation between DFT and experimental results consistently sustains that BY2 dye tends to be adsorbed on the CBA surface by electrostatic interactions, thus, this is the possible adsorption mechanism of this process.

Synthesis, Characterization and Application of a New Functionalized Polymeric Sorbent Based on Alkenylphoshine Oxide

A novel phosphorus-containing sorbent (CyP(Ph)4-DVB) was prepared by copolymerizing divinylbenzene (DVB) with bis α,β-unsaturated phosphorylated cyclohexene (CyP(Ph)4). ATR-FT-IR indicated that the phosphinoyl group was introduced into the sorbent structure. The thermal properties of the sorbent were investigated using a differential scanning calorimeter (DSC), which revealed that (CyP(Ph)4-DVB) is more stable than poly(DVB). The CyP(Ph)4-DVB was applied for cationic dye removal, such as C.I. Basic Yellow 2 (BY2) and C.I. Basic Blue 3 (BB3). Batch adsorption tests suggested that the Freundlich isotherm model seemed to be the better one for the description of equilibrium sorption data at equilibrium, rather than the Langmuir or Temkin models. The Freundlich constants concerning the adsorption capacity of CyP(Ph)4-DVB, kF, were calculated as 14.2 mg1-1/nL1/n/g for BY2 and 53.7 mg1-1/nL1/n/g for BB3.

A novel and simple heat-based method eliminates the highly detrimental effect of xylene deparaffinization on acid-fast stains.

Histopathology is an important method for diagnosing extrapulmonary tuberculosis, yet tissue sections are often negative for mycobacteria after use of acid-fast stain (AFS). This study investigated the mechanism of AFS use and the detrimental effect of histologic processing-in particular, xylene deparaffinization-on AFS and mycobacterial detection. The target of the fluorescent Auramine O (AuO) AFS was investigated using triple staining with DNA- and RNA-specific dyes. The effect of xylene deparaffinization on the acid fastness of mycobacteria in cultures or tissue sections was studied using AuO fluorescence as a quantitative marker. The xylene method was compared with a novel, solvent-free projected-hot-air deparaffinization (PHAD). Co-localization of AuO with DNA/RNA stains suggests that intracellular nucleic acids are the true target of AFS, producing highly specific patterns. Xylene reduces mycobacterial fluorescence significantly (P < .0001; moderate effect size, r = 0.33). The PHAD process yielded significantly higher fluorescence than xylene deparaffinization in tissues (P < .0001; large effect size, r = 0.85). Auramine O can be applied for nucleic acid staining of mycobacteria in tissues producing typical beaded patterns. Acid-fast staining depends heavily on the integrity of the mycobacterial cell wall, which xylene appears to damage. A solvent-free tissue deparaffinization method has the potential to increase mycobacterial detection significantly.

Andisol and microcrystalline cellulose from Typha angustifolia for auramine O adsorption

Andisol has a large surface area, is mesoporous, and contains the active groups' silanol (Si-OH) and aluminol (Al-OH). Besides andisol, cellulose is a good adsorbent, because microcrystalline cellulose has an active hydroxyl group (OH). The number of active adsorbent groups can be enhanced by chemically modifying the surface area (increment), or adding other materials. These modifications included alkaline modified-andisol with the addition of NaOH to increase pore size, cellulose hydrolysis with HCl to increase surface area, and andisol modification with the inclusion of other materials, mainly cellulose, to increase surface area. After the adsorption process is complete, the adsorption capacity of andisol-microcrystalline cellulose (AMS) to auramine O (AO) is known. As an adsorbent for AO, the surface area of BET andisol is 25.92 m&lt;sup&gt;2&lt;/sup&gt;/g and the pore diameter is 14.40 nm, while the surface area of microcrystalline cellulose and AMS adsorbent are 26.60 m&lt;sup&gt;2&lt;/sup&gt;/g and 18.60 m&lt;sup&gt;2&lt;/sup&gt;/g, respectively. The maximum AO adsorption conditions by AMS were at pH 7, optimum at a contact time of 5 minutes, and maximum at a concentration of 40 mg/L with an adsorbent ratio of 1:1. The adsorption kinetics and isotherm more closely followed the pseudo second-order and Langmuir isotherm with an adsorption capacity of 5.24 mg/g.

Constructing trinary heterostructure of TiO2/CoCr2O4/SrTiO3 to enhance photocatalytic activity toward degradation of yellow 28 dye

Today, the design of efficient visible light-driven photocatalytic systems for the degradation of organic dyes is of great interest in human health and environmental protection. Constructing heterostructured nanocomposites using coupling metal oxide semiconductors with visible-light-responsive photocatalytic materials is an effective strategy to improve the photocatalytic potential. For this purpose, a trinary TiO2/CoCr2O4/SrTiO3 heterostructured photocatalyst with enhanced visible-light photocatalytic activity was fabricated using the intimate interfacial contact of TiO2/SrTiO3 nanotubes with CoCr2O4 nanoparticles. Compared with single or binary photocatalysts, trinary TiO2/CoCr2O4/SrTiO3 nanocomposite demonstrated enhanced photocatalytic activity and cycling stability in the degradation of basic yellow 28 (BY28) dye under visible-light irradiation. The optimal TiO2/CoCr2O4/SrTiO3 nanocomposite degraded almost 99% of BY28 under visible light in 2 h, compared to approximately 37%, 66%, and 71% for the SrTiO3 nanorods, CoCr2O4 nanoparticles, and TiO2 nanotubes, respectively. This superior photocatalytic performance can be ascribed to the synergistic effects of elevated photon absorption, charge transfer, and efficient charge separation. In addition, the probable mechanism for the degradation of BY28 dye over TiO2/CoCr2O4/SrTiO3 nanocomposite is also elucidated using PL and active species scavenger studies.

Study on Treatment of Basic Yellow 28 dye Wastewater by Micro-nano Bubble Ozone Catalytic Oxidation

Mn loaded AC (Mn/AC), Cu loaded AC (Cu/AC), and Fe loaded AC (Fe/AC) catalysts were prepared by the impregnation-calcination method, which can be used to degrade Basic Yellow 28 dyes in simulated printing and dyeing wastewater for catalytic ozonation. The catalyst preparation and reaction conditions were optimized with the degradation efficiency of chemical oxygen demand (COD) and the absorbance of some organic compounds under 254 nm UV light (UV254) as indicators. The surface structure, specific surface area, and active component distribution of the catalysts were analyzed by scanning electron microscopy (SEM), nitrogen adsorption, and X-ray diffraction (XRD) characterization. Results indicated that Mn was the best active component, and a catalyst dosage of 3.5 g/L, an initial pH of 9.4, and an initial temperature of 31.7°C were the best reaction parameters to degrade Basic Yellow 28 dyes. After five recycling experiments, the catalysts could retain a relatively stable catalytic effect. Furthermore, this study can be informative for the sustainable development of future catalysts.

Sol-gel combined mechano-thermal synthesis of Y2O3, CeO2, and PdO partially coated ZnO for sulfamethazine and basic yellow 28 photodegradation under UV and visible light

The presence of organic pollutants in marine systems has made wastewater treatment extremely complicated, due to the release of a series of harmful contaminants into the ocean and causing direct damage to humans and the aquatic ecosystem. The present research aims to examine the impact of ZnO partial coating with different nonmetric layers based on CeO2, Y2O3, or PdO for water-charged organic contaminants treatment, using a photocatalysis process. In this vision, the photodegradation of two organic pollutants, sulfamethazine (SMZ) and basic yellow 28 (BY28), using ZnO and ZnO partially coated with cerium, yttrium or palladium oxides was studied. These materials have been successfully synthesized by the combination of both sol-gel and mechano-thermal methods. The prepared catalysts were characterized using X-ray diffraction, scanning electron microscopy SEM-EDX, UV diffuse reflectance spectra (DRS), and X-ray photoelectron spectroscopy analysis (XPS). The XRD measurements discovered that all the synthesized photocatalysts have the hexagonal crystal system of ZnO, and the crystallite size value is calculated to be 36 nm. EDX results affirmed the existence of yttrium, cerium and palladium elements in the prepared ZnO/Y2O3, ZnO/CeO2, and ZnO/PdO materials, respectively, with good dispersion and homogeneity. The XPS spectra of ZnO/Y2O3, ZnO/CeO2, and ZnO/PdO, confirmed the presence of Zn, O, Y, Ce, and Pd elements, where they are, excited as Zn2+, Y3+, Ce4+, and Pd2+ oxidation state, respectively. The photoactivity tests demonstrate that the partial coating increases the degradation efficiency of ZnO, with a total photodegradation of BY28 and SMZ under UV irradiation. Moreover, ZnO/PdO under visible light degrades 94% of BY28 in 120 min and 60% of SMZ in 180 min due to the effective separation of photo-induced charge carriers between PdO and ZnO.

Mg-doped TiO2 nanorods-SrTiO3 heterojunction composites for efficient visible-light photocatalytic degradation of basic yellow 28

In this study, a series of Mg-doped TiO2/SrTiO3 heterojunctions were constructed using SrTiO3 nanoparticles anchored onto the surface of TiO2 nanorod arrays. Titanium dioxide (TiO2) nanorods and SrTiO3 nanoparticles were synthesized using the liquid phase deposition (LPD) and sol-gel methods, respectively. The photocatalytic activity of obtained photocatalysts was investigated towards the degradation of basic yellow 28 (BY28) dye under visible-light irradiation compared to the pristine TiO2 nanorods and SrTiO3 nanoparticles. The obtained samples were carefully characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX), X-ray photoelectron (XPS), UV–Vis, and photoluminescence spectroscopy. 1.5 Mg–TiO2/SrTiO3 nanocomposite demonstrated the highest photocatalytic activity and the corresponding apparent rate constants of 0.0255 min−1 which is that is 2.9, 9.4, and 2.3 times higher than TiO2 nanorods, SrTiO3 nanoparticles, and TiO2/SrTiO3 nanocomposite, respectively. This enhanced photocatalytic performance can be attributed to the improved charge transfer, more effective electron-hole separation, and a red-shift in light absorption derived from the Mg doping and coupling effect of TiO2 nanorods and SrTiO3 nanoparticles.