Dye Phenol Research Articles

Synergistically enhanced photocatalytic properties of Co3O4-G/GO nanocomposites: unravelling their interactions and charge-transfer dynamics using XAS.

Metal oxide composites with graphene/graphene oxide have increasingly gained popularity in enhancing the photocatalytic degradation of several existing harmful dyes. Moreover, identifying the role of carbon networks and their interactions in composite formation would assist in the design and development of photocatalysts. In the present study, we investigated the role of carbon networks in improving photocatalytic properties. Electronic structure analysis of cobalt oxide-graphene (C2)/graphene oxide (C3) nanocomposites using XAS suggested possible charge transfer from cobalt oxide nanoparticles to the carbon network during composite formation. The photocatalytic degradation of C3 towards phenol dye (1×10-3M) was >50% and improved the degradation rate with k = 0.231 h-1.In the quest to understand the mechanism unfolding on its surface, in situ XAS under UV-visible irradiation was performed, which shed light on delayed excitonic recombination in the synthesized nanocomposites. This enabled hydroxy radicals (˙OH) to play a preeminent role in the cleavage of the phenol ring and its intermediaries. Based on these observations, a detailed mechanism for charge transfer occurring during nanocomposite formation and the mechanism involved in the enhanced photocatalytic activity of the nanocomposite photocatalyst towards phenol degradation under the influence of UV-visible irradiation are discussed.

Mesoporous and thermally stable phenol red encapsulated Ag-SiO2 and zincite decorated Ag-SiO2 opto-chemical Sensor

Sol-gel-based silver-doped silicon dioxide (Ag-SiO2) and zincite-decorated silver-doped silicon dioxide (Z-Ag-SiO2) are synthesized at low temperatures (80 °C). The pH indicator dye phenol red (PR) is encapsulated in Ag-SiO2 (AS) and Z-Ag-SiO2 (ZAS) for pH assessment at dynamic pH 12. Thermally stable PR encapsulated AS nanocomposite and PR encapsulated ZAS nanocomposite revealed porous nanostructure with a crystallite size of approximately 0.85 nm and 1.21 nm. The PR/AS and PR/ZAS nanocomposites also feature a surface area of about 438 m2g−1 and 370 m2g−1, respectively. The PR/AS and PR/ZAS demonstrate a pKa of 10.9 and 10.2 at 560 nm, and a rapid color response of approximately 0.46 s and 0.25 s at pH 12.

Tailoring the physical, optical, and structural properties of bismuth oxide to enhance its anionic, cationic, and phenol dye degradation activities

We provide a novel investigation that demonstrates the synthesis of silver-doped bismuth oxide (ABO), holmium-doped bismuth oxide (HBO), nanostructured bismuth oxide (BO), and silver-holmium co-doped bismuth oxide (CDBO) by a cost-effective and straightforward surfactant-assisted co-precipitation technique. In comparison to the BO, ABO, and HBO samples, the optical tests revealed that the CDBO sample exhibited superior photocatalytic characteristics. This is possibly attributed to the physical, optical, and structural properties of the material tailored by the synergistic effect of the adopted strategies, i.e., nanotechnology, oxygen vacancies, and co-doping. The microstructures, physicochemical properties, morphological characteristics, and compositional attributes of the synthesized materials were investigated using sophisticated characterization techniques. The intrinsic conductivity of the bismuth oxide was enhanced with the incorporation of Ag and Ho as co-dopants, as shown by the results obtained from two probe current-voltage experiments. The co-doped sample exhibited the highest efficacy in decomposing rhodamine B dye, with a degradation rate of 91 % during a mere 70-min exposure to W-lamp illumination. The most ideal settings for CDBO photocatalytic activities were identified by comprehensive parameter optimization research. These parameters include a basic pH, a catalyst dosage of 25 mg, a dye concentration of 15 ppm, and an operating temperature of 30 °C. The co-doped and nanostructured photocatalyst also showed an outstanding capability to break down orange II and phenol dye. The trapping experiments' results indicate that the hydroxyl and superoxide radicals play a significant role in the mineralization of the tested dye.

Utilization of river tamarind stem driven biochar for efficient removal of phenol dye from polluted water: insights from adsorption studies

Utilization of river tamarind stem driven biochar for efficient removal of phenol dye from polluted water: insights from adsorption studies

Histidine–cysteine–copper hybrid nanoflowers as active site-inspired laccase mimics for the colorimetric detection of phenolic compounds in PDMS microfluidic devices

Although laccases are essential multicopper oxidases in biosensing and bioremediation, their widespread use is hindered by issues such as instability and high cost. In this study, drawing inspiration from the active site structure of laccase, we developed hybrid nanoflowers through the coordination of copper ions with histidine-cysteine dipeptides (HC–Cu NFs) as highly robust laccase-mimicking nanozymes. The HC–Cu NFs possessed higher laccase-like activity compared to free laccase, yielding an approximately five-fold higher Vmax with a similar Km at the same mass concentration. Additionally, HC–Cu NFs exhibited exceptional stability across diverse environments, including a broad range of pH, temperature, salinity, and extended storage periods. Notably, HC-Cu NFs catalyzed the decolorization of phenolic dyes more rapidly than natural laccase. Utilizing these beneficial features, HC–Cu NFs were incorporated in a polydimethylsiloxane-based microfluidic device, enabling the on-site colorimetric determination of phenolic compounds, such as p-aminophenol, catechol, and hydroquinone, with outstanding sensitivity. By injecting only 20 μL of the sample solution through the inlet of the device, the sample solution rapidly moves to the detection zones where the HC-Cu NFs are retained, followed by catalytic oxidation to further react with 4-aminoantipyrine to produce a colored adduct. Using the microfluidic device, the target phenolic compounds were successfully determined within 20 min at ambient conditions using an image acquired with a smartphone with the ImageJ software. This study unequivocally demonstrates that active site-mimicking dipeptide-incorporated hybrid nanoflowers have the potential to serve as nanozymes, to replace natural laccase. This lays the groundwork for the further advancement of hybrid nanoflower-type nanozymes and their applications, particularly in point-of-care testing environments.

Quantification of Phytochemical Constituents, and Non-Enzymatic Antioxidants of Polyherbal-Formulated Tea on Antitussive, Expectorant, and Analgesic Activity in Rodent

Introduction: Polyherbal formulations maximize therapeutic effects and reduce toxicity by combining effective herbs in specific ratios. The present study aimed to quantify some phytochemical constituents, and some non-enzymatic antioxidants and to estimate the analgesic, expectorant, and antitussive properties of polyherbal-formulated tea (Curcuma longa, Citrus limon, Zingiber officinale, Allium sativum, and Moringa oleifera). Materials and Methods: Some phytochemical constituents and some non-enzymatic antioxidants of the polyherbal tea were evaluated using colorimetric methods. The antitussive efficacy was assessed by examining the cough induced by citric acid in 20 healthy guinea pigs and ammonium in 20 mice. The expectorant activity was evaluated using phenol dye secretion in mice. The analgesic properties were analyzed using pain caused by a hot plate and writhing test caused by acetic acid. Four groups were formed by randomly dividing 20 healthy adult experimental animals (mice and guinea pig), with 5 of both sexes’ animals in each group. Group 1 was given distilled water (10 ml/kg), group 2 was given 5 mg/kg of the polyherbal-formulated tea, group 3 was given 10 mg/kg of the polyherbal-formulated tea, and group 4 was given standard drugs depending on the model of animals used. The tea and standard drugs were administered orally. Results: The result showed that the polyherbal-formulated tea contains phenolic compounds (53.57±1.96 mg/g), alkaloids (40.93±5.96 mg/g), flavonoids (99.44±1.96mg/g), Vitamin C (862±18.76mg/g), carotenoid (5200±6.93 mg/g) and Lycopene (19.50±1.35mg/g). The polyherbal-formulated tea decreased the number of cough bouts and raised the percentage of cough suppression caused by citric acid when compared to the control group. Tea decreased the number of cough bouts caused by ammonium in mice compared to the control group and it raised phenol dye secretion in the expectorant experiment. In hot plate-induced pain, tea increased the latency of the pain threshold in mice and reduced the number of writhing the percentage of pain inhibition increased compared to the control group in acetic acid-induced pain. Conclusion: The polyherbal-formulated tea contains phenolic compounds, alkaloids, flavonoids, Vitamin C, carotenoid, and lycopene and has antitussive, expectorant, and analgesic activity.

Significance of synthesized digenite phase of copper sulfide nanoparticles as a photocatalyst for degradation of bromophenol blue from contaminated water

Organic pollutants such as phenolic compounds have received global interest since they are harmful, toxic, and carcinogenic. This work aimed to synthesize copper sulfide nanoparticles in digenite phase (Cu1.8S) via sol–gel method and apply it as a photocatalyst to remove a phenolic contaminate, bromophenol blue (BPB) dye, from water. The copper sulfide nanoparticles were prepared by the sol–gel technique under different conditions, such as reaction temperature, reactant concentration, and aging time, in the presence of a stabilizing agent (cetyltrimethylammonium bromide, CTAB). The synthesized nanoparticles were then described using different characterization techniques. Then these nanoparticles were applied as a photocatalyst for the degradation of bromophenol blue (BPB) under different conditions, including photo-irradiation time, catalyst dosage, dye concentration and power lamp. The aimed copper sulfide digenite nanoparticles (Cu1.8S) were obtained at a 3 h aging time, exhibiting a cubic crystal structure and a size of 8 nm in a 3-dimensional closed-packed structure model with an energy band gap of 1.82 eV. This material has the ability to absorb visible light and thus can be a superior candidate for photocatalysis, demonstrating strong photocatalytic activity towards the degradation of the phenolic dye (i.e., BPB). Excellent results were achieved at a contact time of 3 h, 7 ppm of BPB, 50 mg catalyst dose, and 32 W power lamp. As a consequence, about 96.7% of the contaminants were removed. The photocatalytic degradation was found to obey the Langmuir postulate and exhibit pseudo first order kinetics.

Cell Staining Microgels Derived from a Natural Phenolic Dye: Hematoxylin Has Intriguing Biomedical Potential.

Hematoxylin (HT) as a natural phenolic dye compound is generally used together with eosin (E) dye as H&E in the histological staining of tissues. Here, we report for the first time the polymeric particle preparation from HT as poly(Hematoxylin) ((p(HT)) microgels via microemulsion method in a one-step using a benign crosslinker, glycerol diglycidyl ether (GDE). P(HT) microgels are about 10 µm and spherical in shape with a zeta potential value of -34.6 ± 2.8 mV and an isoelectric point (IEP) of pH 1.79. Interestingly, fluorescence properties of HT molecules were retained upon microgel formation, e.g., the fluorescence emission intensity of p(HT) at 343 nm was about 2.8 times less than that of the HT molecule at λex: 300 nm. P(HT) microgels are hydrolytically degradable and can be controlled by using an amount of crosslinker, GDE, e.g., about 40%, 20%, and 10% of p(HT) microgels was degraded in 15 days in aqueous environments for the microgels prepared at 100, 200, and 300% mole ratios of GDE to HT, respectively. Interestingly, HT molecules at 1000 mg/mL showed 22.7 + 0.4% cell viability whereas the p(HT) microgels exhibited a cell viability of 94.3 + 7.2% against fibroblast cells. Furthermore, even at 2000 mg/mL concentrations of HT and p(HT), the inhibition% of α-glucosidase enzyme were measured as 93.2 ± 0.3 and 81.3 ± 6.3%, respectively at a 0.03 unit/mL enzyme concentration, establishing some potential application of p(HT) microgels for neurogenerative diseases. Moreover, p(HT) microgels showed two times higher MBC values than HT molecules, e.g., 5.0 versus 2.5 mg/mL MIC values against Gram-negative E. coli and Gram-positive S. aureus, respectively.

Evidence from the use of a solvatochromic detection system indicates that water is an inert carrier of the homeopathic signal

Using a high specification potentiser (Pinkus Potentiser) capable of consistently and reliably producing homeopathic potencies to rigorous standards, unsuccussed control water, Water 10M and Arsenicum 10M have been compared with respect to their effect on the solvatochromic dye phenol blue. Water 10M was found to have no statistically significant effect compared with unsuccussed water whilst Arsenicum 10M produced a statistically significant effect different from both unsuccussed water and Water 10M.
 The conclusion from this result is that bulk pure water does not potentise and is no different from unsuccussed water. This in turn indicates that what is potentised during cycles of dilution and succussion are the substances placed in water and not water itself, and that water is simply an inert carrier of the homeopathic signal.
 Evidence from the practice of homeopathy, in particular the storage and administering of homeopathic medicines, supports this conclusion.

Evidence from the Use of Solvatochromic Dyes Indicates that Bulk Pure Water does not Potentise.

Whilst it is assumed that water plays a crucial role in homeopathy, it is unclear what specific functions water has in the generation, propagation and maintenance of homeopathic potencies. Solvatochromic dyes have demonstrated themselves to be reliable indicators of the presence of potencies and so are well placed to begin to address these questions. The aim of the current study was to ascertain whether pure water could be potentised. If pure water can be potentised, this would indicate that water plays a crucial role in the generation of homeopathic potencies. If it cannot be potentised, then this result points to water being an inert carrier and medium for the potentisation of substances placed in it. A specially designed potentiser capable of consistently and reliably producing homeopathic potencies to rigorous standards (Pinkus Potentiser) was used to run up potencies of "Water 10M" and Arsenicum 10M in two interchangeable stainless-steel vials. "Water 10M" and Arsenicum 10M, along with unsuccussed control water, were then tested against solutions of the solvatochromic dye phenol blue by following the absorbance of the dye at 658 nm. RESULTS ": Water 10M" gave results no different statistically from unsuccussed water (p > 0.05) with no change over the time course of the experiments, whereas Arsenicum 10M gave statistically different results (p < 0.001) with increasing divergence from both "Water 10M" and unsuccussed water over time. Similar results were obtained when the vials in which Arsenicum 10M and "Water 10M" were produced were exchanged, so that the vial in which Arsenicum 10M had been produced was then used to produce "Water 10M" and vice versa, indicating the results could not be explained by any anomalies in the production vials themselves. Results using the solvatochromic dye phenol blue to detect and measure homeopathic potencies indicate that bulk water itself does not potentise and that unsuccussed water and water that has been succussed are no different. This indicates that what is potentised during cycles of dilution and succussion are the substances placed in water and not the water itself. In turn, this indicates that water is simply a carrier for the homeopathic signal. Evidence from the practice of homeopathy supports this conclusion.

The Green Approach of Cerium Oxide Nanoparticle and Its Application for Photo-degradation of Phenol Dye

The approach to the synthesis of cerium oxide nanoparticles (CeO2NPs) using plants as capping agents has been widely researched because of its eco-friendly, low-cost, simple, effective, and reusability. In this research, we used Moringa oleifera leaf extract-mediated CeO2NPs. CeO2NPs were characterized by XRD, FTIR, SEM, TEM, and DRS UV-vis. The photocatalytic activity of CeO2NPs was tested using a phenol dye concentration of 7 mg/L with variations in photocatalyst weight of 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 mg under UV irradiation, respectively, with time variations of 15, 30, 45, 60, 75, 90, 105, 120, 135, and 150 min. SEM and TEM morphology results showed that the CeO2NPs were spherical and agglomerated. The crystal structure is cubic, with a crystal size of 18 nm with a band gap of 2.87 eV. CeO2NPs showed high photo-degradation phenol dye of 94.45% under visible light in 120 min irradiation time. The results show that M. oleifera leaf extract could be as inexpensive and safe for synthesizing other metal oxide nanoparticles, potentially having applications in the biomedical and environmental fields.

Phenolic Compounds from By-Products for Functional Textiles.

Textile dyeing is known to have major environmental concerns, especially with the high use of toxic chemicals. The use of alternatives such as natural dyes rich in phenolic compounds has become extremely appealing in order to move towards a more sustainable circular economy. Phenolic dyes have the potential to functionalize textile fabrics with properties such as antimicrobial, antioxidant, and UV protection. Wastes/residues from the agri-food industries stand out as highly attractive sources of these compounds, with several by-products showing promising results in textile dyeing through the implementation of more sustainable and eco-friendly processes. This review presents an up-to-date exploration of the sources of phenolic compounds used in the textile industry over the past two decades, with a primary focus on the functional properties they provide to different fabrics. The research highlights a surge in interest in this theme since 2017, accentuating a noticeable upward trend. Throughout this review, emphasis is given to by-products from the agri-food industry as the sources of these compounds. The reviewed papers lay the foundation for future research, paving the way for exploring the potential of raw materials and by-products in the creation of functional and smart textiles.

Influence of sodium carboxymethylcellulose on sodium dodecyl benzene sulfonate and sodium dioctyl sulfosuccinate micelles in the presence of phenol red dye

Strong dye-surfactant interactions and innovative formulations are required for dyeing, which is one of the most important operations in the pharmaceutical, food, cosmetic, and textile industries for colouring goods and other uses. The interactions of sodium dioctyl sulfosuccinate (AOT) and sodium dodecyl benzene sulfonate (SDBS) with the dye phenol red (sodium salt of PR) in the presence and absence of the polyelectrolyte sodium carboxymethylcellulose (NaCMC) were investigated using conductometric analysis. The critical micelle concentration (CMC) of SDBS and AOT was found to decrease as PR concentration increased in the water and NaCMC medium. However, in the presence of PR, the counterion binding (βc) of SDBS and AOT increased and negative (∆Gmic°) values indicated that micelle formation was energetically favourable. The results of the UV absorbance experiments indicated that the majority of the binding in the DBS¯ and DS¯ micelles was caused by the ketone proton groups (H+PR¯) of the PR. In NaCMC media, PR (H+PR¯) binding to DBS¯ and DS¯ micelles has been regulated by electrostatic interactions, which have been demonstrated by absorption data and binding constant values. According to dynamic light scattering (DLS) examinations, increasing the amount of PR increased SDBS and AOT micellar size in aqueous and NaCMC media.

Characterizations of MnO2 doped TiO2 nanostructures and effective degradation of methylene blue dye under visible light irradition

Pure and TiO2 doped MnO2 nanoparticles were made using a simple sol-gel technique, and their structural, morphological, characteristics were characteristically examined using XRD, FTIR, and UV-Visible and photocatalytic analysis. Through XRD and SEM analyses, a tetragonal crystalline structure with spherical nanoparticles was discovered. The EDAX experiments provide additional evidence of TiO2's presence in the MnO2 crystal matrix. From UV spectral studies, the band gap energy of MnO2 doped was determined. Photo-degradation study was monitored using methylene blue (MB) and phenol dye solution under visible light irradiation. MnO2 doped catalyst displayed exceptional photocatalytic efficacy towards MB dye under ideal conditions

Bio-Fabrication of Cu/Ag/Zn Nanoparticles and Their Antioxidant and Dye Degradation Activities

The biological synthesis of nanoparticles with copper, silver, and zinc (Cu, Ag, Zn) is reported in this study, adopting a greener, safe, reliable, and eco-friendly approach by using an aqueous leaf extract of Catharanthus roseus. The synthesised trimetallic nanoparticles were characterised using different characterisation techniques. The UV–visible spectroscopic technique was initially used to assess nanoparticle formation, in which absorption bands were observed at 220, 270, and 370 nm for Cu, Zn, and Ag nanocomposites, respectively. XRD revealed that the average crystalline size of the nanocomposites was 34.67 nm. The roles of reducing and capping/stabilising agents in the synthesis of Cu/Ag/Zn nanoparticles were confirmed by FTIR analysis, and the successful biosynthesis of the same was also confirmed by X-ray energy-dispersive spectroscopy (EDX) analysis. Potential applications of these synthesised trimetallic nanoparticles were evaluated by assessing their antioxidant and catalytic dye degradation activities. The antioxidant activity of the synthesised nanomaterial was studied using the DPPH assay. The catalytic breakdown of the harmful dyes phenol red and eosin yellow was examined using NaBH4 as a reducing agent. The results showed that the nanomaterial’s radical scavenging capacity at 1000 ug/mL was 75.76% and the degradation of these dyes was up to 78% in the presence of NaBH4. Furthermore, the biogenic trimetallic nanomaterial exhibited effective catalytic degradation activity against methyl red and phenol red dyes.

Rare earth and transition metal co-doped LaFeO3 perovskite and its CNTs reinforced nanohybrid for environmental remediation application

Herein, rare earth (Gd) and transition metal (Co) co-doped LaFeO3 [La1-xGdxFe1-yCoyO3, (x = 0.08, y = 0.05), LGFCO] perovskite and its carbon nanotube (CNT) reinforced nanohybrid (LGFCO@C) were prepared for the first time via a wet-chemical and post-ultrasonication method. The well-known physical and electronic studies, i.e., XRD, Raman, FTIR, and EDX, were carried out to confirm the doping and CNT reinforcement. The effects of adopted co-doping and reinforcing approaches on the morphology, surface area, conductivity, and band structure were also investigated via SEM, BET, I–V, and UV–vis studies. Due to its hybrid composition, adequate band gap (2.37 eV), greater surface area (105.6 m2 g−1), and superior electronic conductivity (4.432 × 10−1 Scm−1), the LGFCO@C catalyst has remarkable catalytic capabilities for the mineralization of the anionic dye phenol red (PR). Apart from doping, the CNTs reinforced with LGFCO perovskites greatly improved the nano-hybrid's light harvesting and catalytic activity. After only 1 h of exposure to solar radiation, LGFCO@C mineralized 91.6% PR dye with a constant rate value of 0.04 sec−1. A dose of 20 mg of LGFCO@C effectively mineralizes the PR dye in acidic media (pH = 3), according to an optimization study. Furthermore, scavenging tests validate that photo-generated electrons, holes, superoxide, and hydroxyl radicals form during the photocatalytic reaction and play their role in the PR dye mineralization process. The stability and reusability of the LGFCO@C catalyst were also evaluated for five cycles. Even after five successful reusability tests, the LGFCO@C catalyst lost only 11.4% of its activity. Our study indicates that integrating the maximum number of features into a single catalyst is a promising strategy and can open a new avenue in the field of photocatalysis.

Low-Cost Graphene-Based Composite Electrodes for Electrochemical Oxidation of Phenolic Dyes

Electrochemical removal of organic pollutants represents an attractive methodology in water depollution. The key challenges for researchers comprise finding simple, affordable electrode materials with satisfactory efficiency in all ranges of pollutant concentration. Electrochemical oxidation of a mixture of phenol-based dyes: bromocresol green (BCG), cresol red (CR), and thymol blue (TB), in sulphate medium, at total concentration not exceeding 15 ppm, has been performed using simply prepared, low-cost composite electrodes, based on graphene nanoplatelets (GNP) and metallic oxides (TiO2 and SnO2) loaded on stainless steel substrate: GNP@SS, SnO2/GNP@SS, and TiO2/GNP@SS. Electrodes were characterised by XRD, FTIR, and electrochemical techniques. The degradation kinetics of initial dyes was tracked with UPLC and GC-MS chromatography for 6 h, at a current density of 10 mA/cm2. GC-MS analysis of the degradation products revealed oxidised aromatic compounds as the main products, while TOC analysis confirmed a total mineralisation extent in the range of 30–35%. The proposed degradation mechanism involves the attack of OH-radical, as the main oxidising agent, to the hydroxyl oxygens of dye phenolic rings. Obtained results provide useful information for the further development of affordable laboratory-scale and industrial systems for the complete removal of phenol-based compounds.

Unraveling solvent‐dependent hydrogen bonding interaction and excited‐state intramolecular proton transfer behavior for 2‐(benzo[d]thiazol‐2‐yl)‐4‐(9H‐carbazol‐9‐yl)phenol: A theoretical study

AbstractOrganic chemosensors with excited‐state intramolecular proton transfer (ESIPT) behavior have attracted much attention because it has great potential in a wide range of applications. Considering the paramount behavior of excited‐state relaxation, in this work, we mainly focus on deciphering photo‐induced hydrogen bonding effects and ESIPT mechanism for the novel 2‐(benzo[d]thiazol‐2‐yl)‐4‐(9H‐carbazol‐9‐yl)phenol (mCzOH) dye. Considering the effects of different solvents on excited‐state dynamics of mCzOH flurophore, we adopt four solvents with different polarities. Analyses of fundamental structural changes, infrared (IR) vibrational spectra, and core valence partition index between S0 and S1 state, we confirm hydrogen bond OH···N of mCzOH should be enhanced via photoexcitation. Especially, the increase of solvent polarity could promote hydrogen bonding strengthening degree. Intramolecular charge transfer (ICT) resulting from photoexcitation qualitatively facilitates the ESIPT occurrence to a large extent. For further checking and probing into ESIPT mechanism, via constructing potential energy curves (PECs) in four solvents, we clarify the ESIPT behavior for mCzOH. Most worthy of mention is that polar solvent plays critical roles in lowering potential barrier of ESIPT reaction and in facilitating ESIPT process. We not only clarify the detailed excited‐state process, but also present the solvent‐polarity‐dependent ESIPT mechanism for mCzOH fluorophore.

Hierarchical self-assembly of 0D/2D β-Bi2O3 crossandra flower morphology exhibits excellent photocatalytic activity against bromophenol dyes

Crossandra flower shape morphology of β-Bi2O3 nanoflakes was achieved successfully by the solvothermal method. Synthesized β-Bi2O3 nanoflakes were characterized using various characterization techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectra, Ultraviolet–Visible diffuse reflectance spectroscopy (UV-DRS), X-ray photoelectron spectrometer (XPS), N2 adsorption-desorption isotherms (BET), liquid chromatography with mass spectrometry LCMS, Dynamic light scattering (DLS) and Zeta potential (ZP). Moreover, thermal stability and phase change were studied using thermogravimetric analyzer (TGA) and differential thermal analyzer (DTA). The size, shape, and extent of growth was studied using transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDAX), and field emission scanning electron microscopy (FESEM). The crossandra flower shape morphology was achieved due to the effect of temperature (350 °C); this was due to the uniform shifting of heat throughout the material during calcination, which allows material growth along the c-axis. The obtained material was partially in de-agglomerated and agglomerated form, and agglomeration was due to electrostatic forces of attraction. Besides this, the synthesized β-Bi2O3 was utilized to investigate photocatalytic activity for the degradation of bromophenol blue (BPB) and bromocresol purple (BCP). β-Bi2O3 shows the effective catalytic activity as it degrades the phenolic dyes effectively. The degradation was 96% (160 min) and 94% (200 min) for BPB and BCP, respectively. Overall, β-Bi2O3 nanoflakes were more responsive as a photocatalyst for BPB, which took minimal time as compared to BCP.

Chitosan cross-linked polyaniline grafted graphene oxide composite: a new adsorbent to remove phenol and cationic dye from aqueous solutions

ABSTRACT Rapid industrialisation has led to severe environmental pollution, mainly due to the discharge of organic pollutants into the waterbodies. The removal of organic compounds such as dyes and phenolic pollutants from the industrial effluents before it is discharged should be the top priority. This article synthesised a novel chitosan cross-linked polyaniline grafted graphene oxide (CS-PANI@GO) composite with variable morphology, enhanced surface area, low cost, biocompatibility, and notable characteristics of high malachite green (MG) and phenol adsorption capacity. The physicochemical properties of CS-PANI@GO were studied by FESEM, FTIR, XRD, RAMAN, BET, and BJH pore size distribution. FESEM analysis demonstrated that the surface of CS-PANI@GO composite is porous in nature. The BET surface area of the composite is 88.91 m2/g. The effect of various parameters such as temperature, pH of the solution, initial concentration of MG and phenol, adsorption time, and dosage were investigated, and the optimal values were recorded. The adsorption performance of CS-PANI@GO composite for both MG and phenol follows the pseudo-second-order model suggests chemisorption occurs in the process. For MG dye, the adsorption equilibrium data follows the Freundlich model and for phenol, the data follows the Langmuir model. The maximum uptake for MG dye and phenol were 699.022 mg/g and 198.254 mg/g, respectively. Thermodynamic data demonstrated that the process of MG and phenol adsorption was spontaneous, endothermic, and feasible. The recyclability study shows that after five cycles of regeneration, the composite has excellent adsorption performance. The adsorption mechanism is also proposed to be hydrogen bond, π-π interaction, and electrostatic attraction. Based on the present adsorption results under various parameter conditions, the synthesised novel CS-PANI@GO composite could be applied as an efficient adsorbent for the treatment of dyes and phenolic pollutants from wastewater.