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Wastewater pollution is a pressing environmental issue, necessitating effective remediation strategies to mitigate its impact. This study investigates the use of an efficient catalyst for degrading nitrophenols by converting them into useful aromatic amines, which are crucial building blocks for many pharma industries, and photodegradation of various dyes in their unitary solution as well as in mixture. The Cu-Co-Mn ferrite was synthesized using the sol-gel process and sintered at different temperatures. Structural analysis using XRD and Rietveld refinement revealed a crystal structure corresponding to the Fd 3 ‾ m space group having high purity in all the samples. Additionally, the impact of sintering temperature on the magnetic features of the phases were also studied and the findings suggest that all the phases exhibit ferromagnetic behaviour, which means they can be easily separated from reaction mixtures using an external magnetic field. It was also found that higher sintering temperatures lead to a rise in saturation magnetization and magnetic moment with decrease in coercivity (H c). Further, it was observed that Curie temperature (T c) increases with increase in sintering temperature with the exception of CFM400. The catalytic performance of all the catalysts, including CFM400, CFM500, CFM600, CFM800, and CFM1000, was evaluated and the results indicate that CFM400 exhibits the highest catalytic activity for nitrophenols reduction and photodegradation of dyes, which could be accredited to its larger BET surface area and lower PL intensity. Overall, the structural and magnetic features of the catalyst's sheds light on the underlying mechanisms governing their catalytic activity. These insights offer valuable guidance in the designing and development of effective catalysts for sustainable wastewater treatment practices, emphasizing the importance of considering both structural and magnetic features in catalyst design. [ABSTRACT FROM AUTHOR]

Due to the versatile usage and applications of chromium compounds in the industry worldwide, the chromium ions are present in the major effluents from a broad range of industries. Cr(VI) which is highly hazardous and carcinogenic poses a serious threat to the our ecosystem and human health even at very low concentration limits. Cr(III) ions are also toxic to aquatic life, but they are less harmful than Cr(VI) ions. Therefore, detection and analysis of the toxic Cr(VI) and Cr(III) ionic species in waste water are an utmost important area of research. Various chemical reagents and the different methods which require expensive instrumentation used in the past for detection and determination of the non-biodegradable Cr(VI) ions suffer from serious limitations. The present review summarises the use of spectrophotometric methods of determination of Cr(VI) and Cr(III) ions from aqueous solutions with high sensitivity, selectivity, accuracy and at lesser costs. The use of chemical reagents such as diphenylcarbazide (DPC) and several other dye-based reagents for spectrophotometric determination of hazardous Cr ions in water samples is discussed. Additionally, the use of DPC reagent in developing advanced technologies such as microfluidic detection system, microfluidic paper-based analytical devices (µPADs) and 3D printed device with online spectrophotometric detection system for onsite monitoring of water samples is elucidated. Different methods for selective speciation and preconcentration of Cr(VI) ions prior to spectrophotometric determination in water samples with very low concentrations (as low as ppb) of Cr ions are also described. The emerging trends in detection and determination of carcinogenic Cr(VI) ions involving the use of novel and innovative technologies and different categories of nanomaterials are also elucidated in the present review. [ABSTRACT FROM AUTHOR]

Organic luminogens play an indispensable role in optoelectronic devices, yet there is a pressing need to address their aggregation‐caused quenching (ACQ) and stability. Here we designed and prepared multilayered boron nitride nanosheets/fluorescein isothiocyanate (MBNNSs/FITC) composite phosphors with tunable photoluminescence by controlling the FITC content and annealing temperature. The research results indicate that MBNNSs/FITC with low or high loading of FITC is not conducive to enhancing the emission intensity of FITC, which can be attributed to the fact that low loading leads to a decrease in the content of fluorescent groups, while high loading promotes intermolecular aggregation of FITC dyes. Interestingly, the emission intensity of FITC in MBNNSs/FITC‐6 composite phosphors can be further enhanced by annealing treatment (200 °C), which can be ascribed to the suppression of the ACQ and effective energy transfer from the MBNNSs to the FITC. Moreover, the resultant composite phosphor displays outstanding thermal stability, remarkable photo stability and exceptional water‐resistance. This work provides a new design space for the development of non‐rare‐earth fluorescent materials using organic fluorescent dyes. [ABSTRACT FROM AUTHOR]

Despite the excellent thermometric performance of many developed luminescent nanomaterials, their use has not gone beyond proof‐of‐concept in vivo experiments to date. An important issue that needs to be resolved before moving toward true biomedical applications of engineered nanothermometers is their potential toxicity and bioaccumulation in the human body considering the ultimate objective of clinical applications. Since most reported nanothermometers currently are not degradable materials and are mainly based on the incorporation of heavy metal ions, these aspects remain of genuine concern in the fields of nanomedicine, nanobiotechnology, nanotoxicology, and nanopharmacology. This work explores the possibility of designing visible, as well as near‐infrared, emitting luminescent ratiometric nanothermometers based on appropriate organic dye mixtures embedded in hollow disulfide‐bridged periodic mesoporous organosilica (PMO) particles. Such hybrid particles show excellent thermometric performance in the physiological temperature range (20–50 °C), favorable degradability in simulated physiological conditions, as well as no toxicity to healthy normal human dermal fibroblast (NHDF) cells in a wide concentration range. Considering the simplicity of the approach from the synthetic point of view, and the large available library of known fluorescent dyes emitting in various regions of the electromagnetic range, this motif renders a very promising approach to designing novel non‐toxic, decomposable, luminescent ratiometric thermometers. [ABSTRACT FROM AUTHOR]

This article reports the synthesis, along with structural and photophysical characterization of 2‐(2'‐hydroxyphenyl)benzazole derivatives functionalized with various azaheterocycles (pyridine, pyrimidine, terpyridine). These compounds show dual‐state emission properties, that is intense fluorescence both in solution and in the solid‐state with a range of fluorescent color going from blue to orange. Moreover, the nature of their excited state can be tuned by the presence of external stimuli such as protons or metal cations. In the absence of stimuli, these dyes show emission stemming from anionic species obtained after deprotonation (D* transition), whereas upon protonation or metal chelation, ESIPT process occurs leading to a stabilized and highly emissive K* transition. With the help of extensive ab initio calculations, we confirm that external stimuli can switch the nature of the transitions, making this series of dyes attractive candidates for the development of stimuli‐responsive fluorescent ratiometric probes. [ABSTRACT FROM AUTHOR]

Many organic dyes are fluorescent in solution. In the solid state, however, quenching processes often dominate, hampering material science applications such as light filters, light‐emitting devices, or coding tags. We show that the dimethylene‐cyclopropanide scaffold can be used to form two structurally different types of chromophores, which feature fluorescence quantum yields up to 0.66 in dimethyl sulfoxide and 0.53 in solids. The increased fluorescence in the solid state for compounds bearing malonate substituents instead of dicyanomethide ones is rationalized by the induced twist between the planes of the cyclopropanide core and a pyridine ligand. [ABSTRACT FROM AUTHOR]

Valorizing biodegradable raw materials derived from agri‐waste is ecologically beneficial. Employing such materials to produce adsorbents is a smart platform for applications in wastewater purification. Lignin is one of the most plentiful natural biopolymers in the world. Its macromolecular structure possesses phenolic and carboxyl groups that can capture heavy metals and dyes. Lignin can be chemically and physically modified to generate adsorbent materials with enhanced capacity to remove pollutants from wastewater. In this work, lignin has been used as a natural resource to synthesize metal oxide‐based nanoadsorbents. The synthesized lignin‐based green nanomaterials effectively removed common pollutants from wastewater including dyes, heavy metals, and bacteria. The lignin‐based water purification technique holds immense potential to effectively remove the most common pollutants from wastewater. [ABSTRACT FROM AUTHOR]

This study investigates the adsorption of pollutants with different chemical structures; organic Naphtol Green B (NGB) dye and copper on a nanocomposite material with a hexagonal structure of the SBA-15 type. This research is divided into two main parts: the first carries out the synthesis of SBA-15 (Santa Barbra Amourphous) and its derivatives phases functionalized by 3-aminopropyl-triethoxylane (APTES) and calcined at 823 K. The second part presents the influence of the adsorption conditions on the adsorption efficiency of NGB dye and copper. High-resolution X-ray diffractogram (XRD) showed three distinct peaks characteristic of highly ordered mesoporous material. Nitrogen adsorption–desorption isotherm of SBA-15 at 77 K° is type IV typical of mesoporous materials. In addition, Fourier transform infrared spectroscopy (FT-IR) was also used in the characterization before and after the adsorption of the selected pollutants. At optimal conditions of pH 5.2, initial concentration of 50 mg/L, adsorbent dosage of 20 mg, and at adsorption time of 90 min the maximum removal of pollutants reached 76% and the adsorption capacity was 227.25 mg/g for NGB dye and 221.006 mg/g for copper. Furthermore, the adsorption kinetics followed the pseudo-second-order model, indicating that chemisorption was the dominant mechanism and the Sips isotherm model best described the adsorption data. Our research demonstrates that the SBA-15 material after modification is an effective adsorbent for removing effluents regardless of their different chemical structure (organic and inorganic). [ABSTRACT FROM AUTHOR]

The principal objective of this article is a thorough analysis of the usage of inexpensive adsorbents to eliminate dyes from different aquatic environments. Dyes, commonly employed in industries—textiles, pharmaceuticals, and food, pose a significant environmental concern due to their persistence and potential toxicity. In response, researchers have explored the efficacy of low‐cost adsorbents (LCAs) as sustainable and economical alternatives for dye elimination. An overview of the environmental effects of dye contamination and the difficulties in using traditional dye removal techniques is given at the outset of the paper. It then delves into the diverse range of LCAs, including agricultural by‐products, waste materials, and natural substances, that have shown promise in adsorbing and eliminating dye contaminants. Examples of such adsorbents include activated carbon (AC) derived from agricultural residues, bio‐adsorbents from various plant materials, and industrial by‐products with inherent adsorption properties. Key mechanisms involved in the adsorption process, such as surface chemistry, pore structure, and electrostatic interactions, are elucidated to offer a fundamental understanding of the sorption capabilities of these materials. This comprehensive review consolidates the current knowledge on dye removal utilizing LCAs, offering insights into the challenges, advancements, and future directions in this environmentally significant field. The findings underscore the potential of harnessing readily available, sustainable materials as effective sorbents for mitigating the adverse impacts of dye pollutants in aqueous systems. The adsorption capacity is comparable to supplementary adsorbents suggested for the removal of dyes. The widely accessible adsorption properties of basic and acidic dyes do not significantly differ from one another. [ABSTRACT FROM AUTHOR]

Nanotechnology has enormous, economic, social, and environmental ramifications. Due to their capacity to survive in complex processes, inorganic nanomaterials like metal/metal oxides have received substantial study during the past decade. Nanoparticles have antibacterial, magnetic, electrical, and catalytic characteristics due to their greater surface area. There are several methods to develop nanoparticles but environment friendly behavior with no toxic byproducts attracts researchers toward biological process of nanoparticles. This work synthesizes copper oxide (CuO) nanoparticles and zinc oxide (ZnO) with Aloebarbadensis (Aloe vera) leaves extract and successfully characterizes them with different analytical techniques. The catalytic activity of such nanoparticles tests over different cationic and anionic dyes like methylene blue (MB), methyl orange (MO), and methyl red (MR) for different intervals of time and reveals. The degradation efficiency of CuO nanoparticles for MB, MO, and MR dyes are 59.92%, 73.48%, and 73.10% respectively, and for ZnO nanoparticles it is 81.44%, 76.46%, and 63.30% for MB, MO, and MR dyes respectively under the exposure of sunlight for 8 h. The present work successfully develops an ecofriendly process of dye degradation by biologically synthesized nanoparticles. [ABSTRACT FROM AUTHOR]

ABSTRACT Nowadays, surface‐enhanced Raman spectroscopy (SERS) has become a powerful tool for rapidly detecting and analyzing textile cultural relics due to its ability to provide chemical information with single‐molecule sensitivity. However, preserving a high level of detection sensitivity while avoiding sample damage remains a persistent challenge. In this work, we developed a SERS approach with both microextraction and detection functions. The alcohol–water droplet with iodide‐modified Au nanoparticles (AuIMNPs) is directly dropped on the textile, where dyes strongly bound on textiles can be extracted by ethanol (EtOH). As a result, the sample can be well preserved from being damaged. In particular, the volatility of EtOH allows the molecules to be captured in the hot spots through the capillary effect during droplet evaporation, resulting in a dramatic increase in Raman signal intensity. This highly sensitive strategy can be used to measure dyes in plant extracts and mock‐up textiles. Furthermore, the capability of SERS to provide fingerprint information allows us to distinguish different dyes in overdyeing textiles. Eventually, this approach is successfully applied to identify dyes of authentic ancient Chinese textiles. This rapid, universal, and negligibly invasive approach provides a powerful way to study textile cultural relics. [ABSTRACT FROM AUTHOR]

Dyes are one of the most threatening toxins released from industry. Methylene blue (MB) is one of the extremely common dyes in the textile industry. Being complicated in structure and non-biodegradable in nature, removing MB from the aqueous environment is a great challenge. Elimination of dye is usually performed in two ways, degradation, and adsorption. Iron-based nanoparticles, being biocompatible and non-expensive, became a hot field of research in the context of the elimination of toxic dyes. In our review article, we consolidated the data about the synthesis, nature, state, and applications of iron-based nanoparticles to remove MB dye from aqueous solutions specifically via adsorption and degradation. We also reviewed the effect of doping on nanoparticles and their effects on dye removal capacity. Physiological factors such as pH, and temperature play an important role in iron-based nanoparticle synthesis as well as dye degradation and adsorption. A comparative account between adsorption and degradation was tried to depict the elimination of dye in various aspects including efficiency and mechanism. [ABSTRACT FROM AUTHOR]

The current study proposes an introduction of interfering ions to the reaction medium as a simple way for obtaining efficient visible-light driven photocatalysts with active surface based on ZnO nanosheets. 9 samples with different morphological and structural parameters were obtained via simple and inexpensive precipitation and hydrothermal methods. XRD, SEM, FTIR, SSA, XPS, Raman, absorption spectra and DLS methods were used for ZnO nanosheet characterisation. An original approach was used to determine the amount of defects by processing Raman spectra via software specially designed for this purpose. XPS was used to estimate an overall amount of oxygen vacancies in the samples, and the DFT method was employed to model oxygen vacancies in the crystal structure. The latter were verified via absorption spectra. The most effective sample showed a dye degradation efficiency of 94 % after 60 min of irradiating by a common LED lamp available in a local store. The kinetic studies showed that the rate of adsorption and photodegradation depends on the DFT-calculated "surface-dye" interaction energy. Consequently, by regulating the ratio of ZnO nanosheet surface parameters, adsorption and photodegradation efficiency against a particular dye can be improved. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, we developed TiO2-coated aluminum (TiO2/Al) surfaces using eco-friendly methods to create efficient and environmentally friendly photoactive materials with the potential to enhance water purification systems. TiO2 particles were deposited onto aluminum foil surfaces via a spray method, followed by heat treatment at 200 °C for 15 min. The morphology of the TiO2/Al surfaces, both before and after photocatalytic treatment, was characterized using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The photocatalytic properties of these modified surfaces were evaluated through the degradation of rhodamine B (RB), methylene blue (MB), and methyl orange (MO) under simulated solar and UV–LED irradiation. Among the dyes tested, MO exhibited the highest degradation, influenced by factors such as absorption maximum, molecular structure, charge, and the number of condensed rings. The computational study of interactions between dye molecules and the combined nanoparticle revealed that the binding was the strongest in the case of MO dye. This study also explored the influence of varying the number of TiO2/Al surfaces in solution (one, five, and ten) on the photodegradation efficiency. The solution with five TiO2/Al surfaces demonstrated optimal performance, achieving a 16% degradation of RB. The reusability of the TiO2/Al surfaces was confirmed through five successive runs of RB degradation. The results indicate that TiO2/Al surfaces are a promising solution for addressing water contamination challenges and advancing sustainable water treatment practices. [ABSTRACT FROM AUTHOR]

The transition from lab-scale studies to pilot-scale applications is a critical step in advancing water remediation technologies. While laboratory experiments provide valuable insights into the underlying mechanisms and method effectiveness, pilot-scale studies are essential for evaluating their practical feasibility and scalability. This progression addresses challenges related to operational conditions, effectiveness and energy requirements in real-world scenarios. In this study, the potential of nanopulsed plasma bubbles, when scaled up from a lab environment, was explored by investigating critical experimental parameters, such as plasma gas, pulse voltage, and pulse repetition rate, while also analyzing plasma-treated water composition. To validate the broad effectiveness of this method, various classes of highly toxic organic pollutants were examined in terms of pollutant degradation efficiency and energy requirements. The pilot-scale plasma bubble reactor generated a high concentration of short-lived reactive species with minimal production of long-lived species. Additionally, successful degradation of all pollutants was achieved in both lab- and pilot-scale setups, with even lower electrical energy-per-order (EEO) values at the pilot scale, 2–3 orders of magnitude lower compared to other advanced oxidation processes. This study aimed to bridge the gap between lab-scale plasma bubbles and upscaled systems, supporting the rapid, effective, and energy-efficient destruction of organic pollutants in water. [ABSTRACT FROM AUTHOR]

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Advances in green engineering and technology have revealed a number of environmentally acceptable alternatives for water purification. In line with this, recent advances in biosorption of pollutants from aqueous solutions using animal biowaste-based activated carbon (AC) are reported herein. Apart from the fish scale-derived AC which is extensively documented, animal bones, among the rest others, have been studied most widely, followed by hair and feathers. Out of the various target water pollutants, removal of heavy metals has been mostly studied. Majority of the reports showed the Freundlich isotherm and pseudo second order as the best fit. Few investigations on the thermodynamics of the adsorption studies and reports on the Gibbs free energy change (ΔG°), enthalpy change (ΔH°), and entropy change (ΔS°) have also been discussed in this report. It has been concluded that while plant-based AC has gained wide interest, the same is not true for the animal-based counterpart albeit the latter's potential for high sorption efficiency as seen in the present report. [ABSTRACT FROM AUTHOR]

The contamination of water by organic dye compounds are worldwide environmental problem due to their highly toxic nature. To address this environmental issue, a simple technique with highly efficient dye removal was developed to prepare pH‐ sensitive dual‐crosslinked anionic and amphoteric interpenetrating network (IPN) hydrogels based on Na‐carboxymethyl cellulose (Na‐CMC) using jute stick‐based cellulose. Crosslinked Na‐CMC and crosslinked κ‐carrageenan (KC) were interlaced by H‐bonding in anionic IPN hydrogel (An‐gel), but crosslinked Na‐CMC and crosslinked Chitosan (CS) were interlaced by electrostatic interaction in amphoteric IPN hydrogel (Am‐gel). In various operating conditions (pH, temperature, etc.) An‐gel displayed a higher number of swelling ratios of about 2560% at pH 7.2 and Am‐gel of about 1874% at pH 5.5. Based on the point of zero charge, An‐gel achieved the maximum removal efficiency of 81.62 % for methylene blue (MB) at pH 7.2, whereas Am‐gel achieved 85.38% removal efficiency for eosin yellow (EY) at pH 5.5. The adsorption kinetics of IPN hydrogels followed a pseudo‐second order model and best fitted by Langmuir isotherm model. The removal efficiency of MB and EY decreased slightly with increasing temperature. The values of ΔH°, ΔG°, and ΔS° indicated an exothermic, spontaneous, and disordered adsorption process. [ABSTRACT FROM AUTHOR]

Currently, water pollution caused by dyes is a serious problem since they are toxic and carcinogenic to living beings. To reduce the presence of these contaminants, natural adsorbents have been considered as they are easy to obtain, inexpensive, and have high removal efficiency. In this work, the adsorption process using natural brushite (nDCPD) was studied for the removal of phenol red (PR), achieving a removal rate of 99.15% and an adsorption capacity of 82.24 mg/g, and gentian violet (GV), achieving a removal rate of 97.03% and an adsorption capacity of 74.22 mg/g. Equilibrium adsorption occurs for both dyes in multiple layers on the surface. The adsorption process is spontaneous for both dyes. The kinetics of the adsorption process involve using a single active site on the surface for PR adsorption, while for GV, two active sites on the surface are required. Analysis via FTIR, EDS, and XRD revealed various mechanisms that intervene in the adsorption process of both dyes on the surface of nDCPD, such as electrostatic forces, functional groups, physisorption, and ion exchange. [ABSTRACT FROM AUTHOR]

Sorption technologies have been proposed for the treatment of water containing methylene blue (MB), a toxic and persistent pollutant. Despite its environmental risks, the role of process variables in MB removal has not been fully explored through experimental design. The objective of this study is to assess the potential of bone meal powder (BMP), an underexplored agricultural byproduct, as an affordable adsorbent for the removal of MB from water. BMP was subjected to a series of analytical characterization techniques, and its adsorption capacity was evaluated through a comprehensive factorial design, which investigated the effects of biosorbent dosage, solution pH, and initial MB concentration. The study revealed that the highest adsorption level was 14.49 mg g-1, attained under the following conditions: 1 g L-1 BMP, pH 11, and 100 mg L-1 MB. The adsorption equilibrium was reached within 60 min, with a measured capacity (qexp) of 18 mg g-1. Theoretical adsorption isotherms indicated a capacity of 63 mg g-1, which aligned well with the Langmuir model. To predict adsorption outcomes, machine learning models were applied, with multiple linear regression performing best. Optimization of decision trees and neural networks improved accuracy but risked overfitting. FT-IR, XRD, and ICP analyses indicated ion exchange as a significant mechanism of adsorption. In desorption studies, H2SO4 was the most effective agent, achieving 68.72% desorption efficiency. BMP exhibited optimal recyclability for up to four cycles before efficiency declined. [ABSTRACT FROM AUTHOR]

Pollutant removal from different sources, especially water pollutants, is a major concern in today's world. Various methodologies were being utilized to purify water resources because water scarcity is a major problem of the twenty-first century. In the current study, we searched and discovered novel green, renewable, cost-effective, environmentally benign, and readily available adsorbent Aerva Javanica (A. Javanica), for remediation of selected fourteen (14) dyes from aqueous media. A quantitative structure–property relationship model was developed to relate the structural properties of dyes with the percentage adsorption based on data and information which was collected by the adsorption study of these selected dyes. The structures of these dyes were optimized using MOPAC2016 and DRAGON software and further used for descriptors calculation. Initially, 1666 descriptors were calculated. The heuristic method was employed to select significant descriptors, and after pre-reducing steps, we left with 36 descriptors. Stepwise multiple linear regression (SMLR) analysis followed by artificial neural network (ANN) was employed on these descriptors for model generation. The SMLR-ANN model has shown better predictive ability (R2 = 0.9907) than only the SMLR model (R2 = 0.9778). Validation of the model was performed by internal validation by measuring cross-validation squared correlation coefficient (Q2 = 0.921) and external validation (predictive R2 = 0.9211). Significant descriptors calculated for modeling include Mor10e, HATS5p, nHAcc, E3m, and GATS5v. All these descriptors are built on basic molecular properties like molecular structure, electronegativity, and polarity. So the model is significant in this regard as it relates basic molecular properties with their adsorption potential. Generated models have shown good robustness, stability, and predictive ability. [ABSTRACT FROM AUTHOR]

This research investigates methylene blue as a high-performance photocatalyst in the photo-oxidation conversion of alcohols to aldehydes. The present study investigates the optimal conditions for the solvent effect, catalyst, and oxidant amount. The objective is to identify the most practical combination of these factors to optimize the desired outcome of the experiment. The notable characteristics of this transformation include its gentle conditions, the use of a metal-free organic dye as a photocatalyst, and TBHP's dual function as both a radical initiator and a means for regenerating the photocatalyst. This research provides valuable insights into the potential of methylene blue as a high-performance photocatalyst in the photo-oxidation reaction of alcohols, paving the way for more efficient photocatalytic processes. [ABSTRACT FROM AUTHOR]

Activated carbon was prepared at 300 °C and 600 °C, characterized by SEM, EDX and XRD, and was then used as an adsorbent for the removal of acidic dyes; acid yellow 25 and acid red 4. The activated carbon prepared at high temperature (600 °C) due to its high carbon contents and surface area was subsequently used as adsorbent for the selected dyes adsorption using batch adsorption approaches to estimate different adsorption parameters. For the estimation of kinetics and equilibrium parameters a number of kinetics and isotherm models were employed. Dyes were adsorbed on activated carbon surface at a high rate for the first 15 min, after which it began to diffuse into the micro pores and thus the process became steady. The rate constant was estimated for first and second order kinetics models. The maximum adsorption capacities recorded were 526.32 mg g−1 for acid red 4 and 555.55 mg g−1 for acid yellow 25. The enthalpy change values recorded were; 19.44 kJ mol−1 for acid yellow 25 adsorption and 16 kJ mol−1 for acid red 4 adsorption, meant that the process is endothermic. The negative values of Gibbs free energy change (−393.28, −1,515.48, −2,634.68 J mol−1) of acid red 4 and acid yellow 25 (−251.72, −1,058.06, −2,367.84 J mol−1) at tested temperatures, confirmed the feasibility and spontaneity of the adsorption processes. The adsorption of dyes on the carbon surface was diffusion-controlled process, as demonstrated by the linear graph of intraparticle diffusion model. [ABSTRACT FROM AUTHOR]

One major environmental issue responsible for water pollution is the presence of dyes in the aquatic environment as a result of human activity, particularly the textile industry. Chitosan–Polyvinylpolypyrrolidone (PVPP) polymer composite beads were synthesized and explored for the adsorption of dyes (Bismarck brown (BB), orange G (OG), brilliant blue G (BBG), and indigo carmine (IC)) from dye solution. The CS-PVPP beads demonstrated high removal efficiency of BB (87%), OG (58%), BBG (42%), and IC (49%). The beads demonstrated a reasonable surface area of 2.203 m2/g and were negatively charged in the applicable operating pH ranges. TGA analysis showed that the polymer composite can withstand decomposition up to 400 °C, proving high stability in harsh conditions. FTIR analysis highlighted the presence of N-H amine, O-H alcohol, and S=O sulfo groups responsible for electrostatic interaction and hydrogen bonding with the dye molecules. A shift in the FTIR bands was observed on N-H and C-N stretching for the beads after dye adsorption, implying that adsorption was facilitated by hydrogen bonding and Van der Waals forces of attraction between the hydroxyl, amine, and carbonyl groups on the surface of the beads and the dye molecules. An increase in pH increased the adsorption capacity of the beads for BB while decreasing OG, BBG, and IC due to their cationic and anionic nature, respectively. While an increase in temperature did not affect the adsorption capacity of OG and BBG, it significantly improved the removal of BB and IC from the dye solution and the adsorption was thermodynamically favoured, as demonstrated by the negative Gibbs free energy at all temperatures. Adsorption of dye mixtures followed the characteristic adsorption nature of the individual dyes. The beads show great potential for applications in the treatment of dye wastewater. [ABSTRACT FROM AUTHOR]

The Dagulf Psalter is a precious Carolingian manuscript on calf parchment, dated to 793–795. Its unique and high historical value required a non-invasive, multi-analytical approach to gain insights into the material composition of gold and silver inks, pigments, and dyes used for writing and illuminations. Elemental mapping based on X-ray fluorescence analysis (XRF), Fibre Optics Reflectance Spectroscopy (FORS) measurements, and hyperspectral imaging (HSI) gave complementary information on colour media and their brilliant shades. Knowledge of the material composition of inks, dyes, and pigments is of crucial importance not only for art historical research, but also for the preservation of the manuscript, as it is known that among other factors, silver inks and some pigments can lead to deterioration of parchment supports. The purple dye orchil and blue indigo were used for painted backgrounds on the initial folios. Lapis lazuli was found in decorative frames on these folios. Orchil, indigo, and lapis lazuli also appear in decorations of small initials throughout the manuscript. Red lead, ochre, cinnabar, orpiment, and lead white were also found in various painted details. Gold and silver inks of high purity were identified. The proof of chlorine in the silver ink indicates the presence of corrosion products. [ABSTRACT FROM AUTHOR]

The lanasyn black is among the most often used in manufacturing and is challenging to take out during the treatment of wastewaters from textile industry. The cloud point extraction was used for their elimination from an aqueous solution. The multivariable process parameters have been independently optimized using the central composite design and the Levenberg-Marquardt algorithm-based artificial neural network for the highest yield of the extraction of lanasyn black via the cloud point extraction. The CCD forecasts the output maximum of 97.01 % under slightly altered process parameters. Still, the ANN-LMA model predicts the extraction yield (99.98 %) using 1.04 g of KNO3, the beginning pH of solution 8.99, the initial content of lanasyn black 24.57 ppm and 0.34 mass % of Triton X-100. With the coefficients of determination of 0.997 and 0.9777, the most recent empirical verification of the model mentioned above predictions using CCD and ANN-LMA is determined to be satisfactory. [ABSTRACT FROM AUTHOR]

Background: Strongyloidiasis, a parasitic infection, presents a significant public health challenge in tropical regions due to the limited repertoire of effective treatments. The screening of chemical libraries against the therapeutically relevant third-stage larvae (L3) of the model parasite Strongyloides venezuelensis yielded meager success rates. This situation is reminiscent of Gram-negative bacteria, where drug entry is a limiting factor. Methods: Here, we set out to determine whether similar barriers are in place and establish whether structural and property requirements exist for anti-strongyloides drug discovery. We focused on dyes as their uptake and effects on viability can be independently assessed in the multicellular parasite, thus providing a means to study the possibility of similar entry rules. We tested different dyes in in vitro assays on L3s. Results: We found that staining was necessary to reduce parasite viability, with some dyes achieving anti-strongyloides effects at concentrations similar to those of the reference drug, ivermectin (IV). Some dyes also showed activity against female adults at concentrations well below that of ivermectin. Unfortunately, the most potent dye, Methylene Blue, was unable to prevent the infection in a preliminary in vivo mouse model assay, presumably due to fast dye clearance. Structural analysis showed that positive charges facilitated the access of the compounds to the L3 tissue, thus providing a structural tool for the introduction of activity. For female adults, low globularity is additionally required. As a proof of concept, we added a positive charge to an inactive compound of one of our chemical libraries and re-determined the activity. Conclusions: These findings allow us to establish structural rules for parasite entry that could be of interest for future drug screening or drug development campaigns. These rules might also be applicable to other related parasites. [ABSTRACT FROM AUTHOR]

The adsorption properties of microporous carbon materials modified with iron citrate were investigated. The carbon materials were produced based on resorcinol-formaldehyde resin, treated in a microwave assisted solvothermal reactor, and next carbonized in the tube furnace at a temperature of 700 °C under argon atmosphere. Iron citrate was applied as a modifier, added to the material precursor before the synthesis in the reactor, in the quantity enabling to obtain the nanocomposites with C:Fe mass ratio equal to 10:1. Some samples were additionally activated using potassium oxalate or potassium hydroxide. The phase composition of the produced nanocomposites was determined using the X-ray diffraction method. Scanning and transmission electron microscopy was applied to characterize the changes in samples' morphology resulting from the activation process and/or the introduction of iron into the carbon matrix. The adsorption of nitrogen from gas phase and dyes (methylene blue and congo red) from water solution on the obtained materials was investigated. In the case of methylene blue, the adsorption equilibrium isotherms followed the Langmuir isotherm model. However, in the case of congo red, a linear dependency of adsorption and concentration in a broad equilibrium concentration range was found and well-described using the Henry equation. The most efficient adsorption of methylene blue was noticed for the sample activated with potassium hydroxide and modified with iron citrate, and a maximum adsorption capacity of 696 mg/g was achieved. The highest congo red adsorption was noticed for the non-activated sample modified with iron citrate, and the partition coefficient for this material equaled 171 dm3/g. [ABSTRACT FROM AUTHOR]

Industrial wastewater discharge, tainted with hazardous substances, including dyes like methylene blue (MB) from the textile sector, further emphasizes the need for water treatment to produce safe drinking water. This study explores the potential of olive mill solid waste, an abundant and cost-effective agricultural waste in Mediterranean regions, to yield high-quality activated carbon (AC) with zinc chloride activation for MB adsorption. The activation process, carried out at a modest temperature of 500 °C without the need for an inert atmosphere, resulted in AC with remarkable characteristics, boasting a substantial surface area of 1184 cm2·g−1 and a total pore volume of 0.824 cm3·g−1. Extensive characterization of the AC was carried out through a large range of surface techniques. The pH of the solution had minimal influence on MB adsorption, the maximum removal was 95%, which was under slightly acidic pH conditions (5.8), and the adsorbent dose was 0.4 g·L−1 for a 50 mg·L−1 MB concentration. Equilibrium data pertaining to MB adsorption were subjected to fitting with different models, namely Langmuir, Freundlich, and Temkin. Notably, the Langmuir model exhibited the best fit, revealing a maximum monolayer adsorption capacity of 500 mg·g−1 at 25 °C, and the adsorption kinetics closely followed a pseudo-second-order model. [ABSTRACT FROM AUTHOR]

In this work, we designed and synthesized two novel bi-heteroatom functionalized hyper-crosslinked porous polymers (HCP-CT and HCP-CF) through a simple one-step Friedel–Crafts alkylation reaction. The resulted polymers N/S bi-heteroatom functionalized polymer HCP-CT and N/O bi-heteroatom functionalized polymer HCP-CF both have good adsorption property for organic dyes such as methyl orange (MO) and methylene blue (MB) in aqueous solution due to its rich pore structure, high specific surface area and rich-heteroatoms of pore surface. It is worth mentioned that the maximum adsorption capacity (qmax) of cationic dye MB by the porous polymer HCP-CT at room temperature was reached up to 1571.46 mg/g, which is much higher than that of most reported porous materials. Furthermore, the adsorption capacity of HCP-CT for the cationic dye MB was more than seven times that of the anionic dye MO (qmax = 212.77 mg/g). Also, the polymer HCP-CF for the MB adsorption capacity (qmax = 352.11 mg/g) was more than twice higher than that of anionic dye MO (qmax = 131.75 mg/g). The above trends may be because of the stronger electrostatic interaction between the negatively charged N-S/O bi-heteroatom of HCP-CT and HCP-CF with the cationic dye MB than that of MO. In addition, the removal percentage of polymers HCP-CT and HCP-CF still remained above 80% after five adsorption–desorption cycles. Hence, this work may provide a convenient synthetic route to develop a novel hyper-crosslinked polymer with high capacity for the entrapment of dyes from aqueous solution. [ABSTRACT FROM AUTHOR]

The present study is focused on the synthesis of zero-valent iron/cellulose acetate (Fe0-x/CA) membranes by phase inversion route for the activation of peroxymonosulfate (PMS). The generated •OH and SO4•− effectively degraded methylene blue (MB) dye in water to give comparatively non-toxic byproducts. The SEM investigations revealed that Fe0 nanoparticles are evenly dispersed into the CA membrane resulting in decline of agglomeration and enhancing the roughness of the composite surface. Moreover, the catalytic degradation of MB demonstrated that M5-alone showed 85% and was further boosted to 97% when coupled with PMS (M5/HSO5−). The catalytic degradation of degradation of MB by M5/HSO5− membrane system in acidic, neutral, and basic media indicated that the degradation was 99.5%, 98.0%, 97.0%, 86.0% and 70.0% when the pH of the medium was 3, 5, 7, and 11, respectively. Furthermore, the degradation performance of M5/HSO5− membrane system was evaluated in de-ionized water (DIW), tape water (TPW) and industrial wastewater (IWW) and the results indicated that MB catalytic degradation was in the order of DIW (97%) > TPW (84%) > IWW (68%). Besides, various parameters like water flux permeability, contact angle, porosity, and fouling performance were also investigated. In addition, the degradation products were evaluated, and the degradation pathways were proposed accordingly. [ABSTRACT FROM AUTHOR]

This article examines how colour was used as a tool of pictorial narrative in the Bayeux Tapestry and the illustrated Old English Hexateuch, the two longest such cycles to survive from 11th-century England. The dyes employed for the former and the pigments of the latter are identified; the palettes that they permitted their respective artists to realize are set out; the colouring of cognate scenes are compared; and the general principles (such as they were) that affected the deployment of colour in the two works are explained. [ABSTRACT FROM AUTHOR]

Tannins are capable of producing natural dyes with antioxidant and antibacterial propertis, while synthetic dyes are commonly used in the textile industry, causing environmental issues like water pollution. This research aims to utilize waste tannins as natural dyes as an alternative to synthetic dyes. This study examined the effect of the extraction method on tannin properties such as phenolic content, antioxidants, and antibacterial activity. In addition, Pyrolysis Gas Chromatography‒Mass Spectrometry (Py-GCMS) analysis was used to identify the effect of extraction temperature on the chemical elucidation of tannin. The effect of tannin concentration was evaluated against four bacteria that are usually found on human skin: Staphylococcus epidermidis, Bacillus subtilis, Propionibacterium acnes, and Staphylococcus aureus. Extraction temperature significantly influences the chemical composition of tannin, which leads to different antioxidant properties. The maximum antibacterial properties of tannin were obtained at 90°C with the inhibition zone in the range of 0.9–1.0 mm against four bacteria, tannin yield of 26.59%, Gallic Acid Equivalents or total phenolic content (GAE) of 40.30 mg/g, and Radical Scavenging Activity or antioxidant activity (RSA) of 89.88%. Moreover, the concentration of tannin was significantly linear with its antibacterial properties. Tannin was successfully applied to the textile by using alum as a mordanting agent to create an antibacterial textile. The textile's bacterial structure damage was analyzed under Field Emission Scanning Electron Microscopy (FESEM). After 50 washings, tannin-textiles with alum-modified properties remained stable compared to those without alum, with S. aureus and S. epidermidis being the most vulnerable bacteria, as confirmed by FESEM images. Hence, tannin is a feasible alternative to harmful and nondegradable synthetic dyes and antibacterial agents. [ABSTRACT FROM AUTHOR]

Synthetic and untreated dyes discharged in wastewater effluents are a threat to an ecosystem. This study investigated dye degradation and detoxification efficiency of crude lignin peroxidase separately obtained from the cultures of Escherichia coli (LR0250096.1) and Pseudomonas aeruginosa (CP031449.2). The ability of the crude lignin peroxidase to degrade Malachite Green (MG), Remazol Brilliant Blue R (RBBR), Congo Red (CR), and Azure B (AZ) was evaluated at different operating conditions (enzyme, dye, and hydrogen peroxide concentrations; pH; temperature; and contact time). The ability of the degraded dyes to support the growth of bacteria was also investigated. The observed optimum operating conditions for lignin peroxidase extracts of the Escherichia coli on AZ were 20 mg/mL enzyme concentration, 50 mg/L dye, pH 7.0, temperature 50 °C, and 1.5 mM hydrogen peroxide within 20–50 min of incubation time and on MG were 20 mg/mL, 50 mg/L, 9.0, 30 °C, 0.1 mM, and 20 min, respectively. The enzyme extract from Pseudomonas aeruginosa on AZ demonstrated optimum operation conditions of 20 mg/mL, 50 mg/L, pH 9.0, 40 °C, 1.5 mM, and 50 min, respectively and on MG, they were 20 mg/mL, 50 mg/L, 6.0, 30 °C, 1.0 mM, and 20 min, respectively). The prepared enzyme showed an appreciable degradative effect on CR and RBBR compared with commercial lignin peroxidase. The degraded dyes were able to support the growth of two Gram-positive (Bacillus cereus and Staphylococcus aureus), and two Gram-negative (Proteus mirabilis and Escherichia coli) bacteria, indicating the efficiency and the potential use of the enzyme complexes in the clean-up of industrial dyes' waste. [ABSTRACT FROM AUTHOR]

The dyeing process in textile industries has significant environment implication, primarily due to the release of a large amount of water effluents. Photocatalyst is a perennially effective technique used for the degradation of toxic, low- biodegradable hazardous effluents from water bodies. This method is highly selective, cost-effective, straightforward synthesis, and environmentally friendly process. Semiconductor metal oxides-based photocatalysts have gained attraction due to their superior properties including less toxicity and environment applications. However, their widespread implementation has diminished because of the poor photocatalytic activity in the visible region. To address this limitation, incorporating a conducting polymer particularly Polyaniline, has proven more effective. The enhanced charge-carrying capacity and ability to change the optical band gap makes the semiconductor more efficient for the degrading the organic effluents from the water bodies. This review primarily focuses on degradation of poisonous dyes present in textiles wastewater, using the polyaniline-semiconductor nanocomposite as a photocatalyst material. [ABSTRACT FROM AUTHOR]

This work is focused on the visualization of latent fingerprints left on unfired brass cartridges. Polymer films were prepared from 2 mM neutral red or 5 mM toluidine blue using two different electrochemical methods (cyclic voltammetry or chronoamperometry) with relatively short polymerization times. The conditions for the deposition of conductive polymers, poly(neutral red) and poly(toluidine blue), from a neutral medium (phosphate buffer with 0.1 M KNO3 or 0.1 M KNO3, respectively) were optimized to produce high-quality visualization of the remaining fingerprints on the brass substrates. The surface morphology and quality of the polymer films after the electrochemical deposition of both polyphenazine dyes were characterized by stereomicroscope. Phenazine dyes, which were used for the visualization of fingerprints, have been shown to provide different degrees of homogeneity in the deposited film. Furthermore, the dependence of the stability of the monomer solutions on their age, use, and storage conditions are discussed. Finally, a methodology is proposed for how to apply this technique of visualizing latent fingerprints with observed details of papillary lines in forensic practice. [ABSTRACT FROM AUTHOR]

Dye decolorization through biological treatment techniques has been gaining momentum as it is based on suspended and attached growth biomass in both batch and continuous modes. Hence, this review focused on the contribution of moving bed biofilm reactors (MBBR) in dye removal. MBBR have been demonstrated to be an excellent technology for pollution extraction, load shock resistance, and equipment size and energy consumption reduction. The review went further to highlight different biocarrier materials for biofilm development this review identified biochar as an innovative and environmentally friendly material produced through the application of different kinds of reusable or recyclable wastes and biowastes. Biochar as a carbonized waste biomass could be a better competitor and environmentally friendly substitute to activated carbon given its lower mass costs. Biochar can be easily produced particularly in rural locations where there is an abundance of biomass-based trash. Given that circular bioeconomy lowers dependency on natural resources by turning organic wastes into an array of useful products, biochar empowers the creation of competitive goods. Thus, biochar was identified as a novel, cost-effective, and long-term management strategy since it brings about several essential benefits, including food security, climate change mitigation, biodiversity preservation, and sustainability improvement. This review concludes that integrating two treatment methods could greatly lead to better color, organic matter, and nutrients removal than a single biological MBBR treatment process. [ABSTRACT FROM AUTHOR]

Nano-biocomposite hydrogel samples were produced using graphene oxide (GO) and agar and applied as adsorbents of organic components in water. The hydrogels were prepared by varying the wt% of Agar and GO. The samples were characterized, and batch adsorption experiments evaluated the effect of initial pH, equilibrium isotherms, and kinetics for the adsorption of the anionic dye Acid Orange 7 (AO) and the cationic dyes Nile Blue A (NB) and methylene blue (MB) in an aqueous medium. Overall, both hydrogel samples exhibited satisfactory results for removing NB and MB; however, there was no effective removal for the anionic dye AO. Adsorption equilibrium isotherms were obtained, and Freundlich, Langmuir, and Sips models were fitted to the experimental equilibrium data; moreover, kinetic data were adjusted to driving force models and particle mass balance. The maximum experimental adsorption capacities, 141.48 mg·g−1 (MB) and 284.69 mg·g−1 (NB), were obtained, on a dry basis, for the sample produced with 70 wt% of agar and 30 wt% of GO. Both hydrogels exhibited remarkable regenerative potential for NB and MB, with the adsorption capacity remaining constant, even after five adsorption/desorption cycles. [ABSTRACT FROM AUTHOR]

The printing and dyeing wastewater has high chromaticity, biorefractory properties, and significant toxicity. In this study, PVDF-PVA/GO was synthesized for dyes' adsorption with various chemical properties. Incorporating graphene oxide (GO) into the composite substantially enhanced the hydrophilicity and electronegativity of the PVDF membrane. Results indicated that the adsorption efficiencies for rhodamine B (RhB) and methylene blue (MB) are higher than those of methyl orange (MO) and bromocresol green (BCG). At an initial pH of 8, the maximum adsorption capacities for RhB and MB were 11.81 and 9.25 mg/g, respectively, while MO and BCG indicated considerably lower capacities of 0.59 and 0.63 mg/g, respectively. The cyclic utilization of the PVDF-PVA/GO revealed minimal degradation in adsorption efficiency. The adsorption kinetics of the four dyes primarily follow intra-particle diffusion mechanisms, resulting in the binding of dye molecules to the PVDF-PVA/GO membrane through electrostatic interactions. Notably, competitive adsorption phenomena were observed in mixed dye systems, especially between RhB and MB. Comparative analyses indicated an increased adsorption capacity for MB in the mixed dye system, accompanied by a notable reduction in the adsorption capacity of RhB. This study provides a theoretical foundation for the remediation of printing and dyeing wastewater. Highlights: PVDF-PVA/GO membrane was prepared for the printing and dyeing wastewater treatment. The loading of GO significantly improved the hydrophilicity of PVDF membranes. Anionic, cationic, and non-ionic dyes exhibited opposite adsorption. There are differences in adsorption between single-dye and mixed-dye systems. [ABSTRACT FROM AUTHOR]

Environmental remedy calls for scientific contributions with ever increasing urgency. This research aims to a circular economy look to deliver the concept of novel materials, created from renewable by-product waste feedstock and designed to be reused, recycled, then the feedstock renewed through wastewater treatment process. The use of alum sludge (AS) waste as a photocatalyst in the catalytic oxidation of wastewater to the potential capability of ˙OH radical use as a strong oxidant is explored. Investigation has performed using magnetite (M) augmented with alum sludge as a composite material formed as alum sludge/magnetite (ASM) at different proportions (1:1), (1:2), (1:3), (1:5) and (2:1) and the samples labelled as ASM-1, ASM-2, ASM-3, ASM-4 and ASM-5, respectively. The characterisation of such composite materials was explored by X-ray diffraction (XRD), Transmission electron Microscopy (TEM) and the composition of the composite material is attained by the Energy dispersive X-ray spectroscopy (EDX). The capabilities of these materials are tested for dye removal. Consequently, the corresponding photocatalytic performance was notably improved. The various operating conditions, initial dye concentration, initial pH value, catalyst and H2O2 concentrations on the oxidation efficiency of the dye were optimised at pH 2.0 and 800 mg/L and 2 g/L for H2O2 and ASM-1, respectively. Thermodynamic and kinetics were studies and the data revealed that the reaction is spontaneous and exothermic in nature and follows the first-order reaction kinetics. This assessment introduces the role of engineers and chemists in a world without waste. [ABSTRACT FROM AUTHOR]

Abstract To obtain high efficient elimination of ammonia (NH4 +) from wastewater, Cu(II), Ni(II), and Co(II)) were loaded on Dowex-50WX8 resin (D-H) and studied their removal efficiency towards NH4 + from aqueous solutions. The adsorption capacity of Cu(II)-loaded on D-H (D-Cu2+) towards NH4 + (qe = 95.58 mg/g) was the highest one compared with that of D-Ni2+ (qe = 57.29 mg/g) and D-Co2+ (qe = 43.43 mg/g). Detailed studies focused on the removal of NH4 + utilizing D-Cu2+ were accomplished under various experimental conditions. The pseudo-second-order kinetic model fitted well the adsorption data of NH4 + on D-Cu2+. The non-linear Langmuir model was the best model for the adsorption process, producing a maximum equilibrium adsorption capacity (qmax = 280.9 mg/g) at pH = 8.4, and 303 K in less than 20 min. The adsorption of NH4 + onto D-Cu2+ was an exothermic and spontaneous process. In a sustainable step, the resulting D-Cu(II)-ammine composite from the NH4 + adsorption process displayed excellent catalytic activity for the degradation of aniline blue (AB) and methyl violet 2B (MV 2B) dyes utilizing H2O2 as an eco-friendly oxidant.

In this review, topic modeling—an unsupervised machine learning tool—is employed to analyze research on pigments in cultural heritage published from 1999–2023. The review answers the following question: What are topics and time trends in the past three decades in the analytical study of pigments within cultural heritage (CH) assets? In total, 932 articles are reviewed, ten topics are identified and time trends in the share of these topics are revealed. Each topic is discussed in-depth to elucidate the community, purpose and tools involved in the topic. The time trend analysis shows that dominant topics over time include T1 (the spectroscopic and microscopic study of the stratigraphy of painted CH assets) and T5 (X-ray based techniques for CH, conservation science and archaeometry). However, both topics have experienced a decrease in attention in favor of other topics that more than doubled their topic share, enabled by new technologies and methods for imaging spectroscopy and imaging processing. These topics include T6 (spectral imaging techniques for chemical mapping of painting surfaces) and T10 (the technical study of the pigments and painting methods of historical and contemporary artists). Implications for the field are discussed in conclusion.

Spectroscopic techniques were carried out to identify the dyes used on the famous mediaeval Lady and the Unicorn tapestries kept in the Cluny Museum. Among the six tapestries, La Vue shows a colour variation between the front, which appears blue, and the back, which appears violet, on the Lady’s skirt. In the Middle Ages, it was common for the violet colour to be made with a blue dye bath (woad or indigo) followed by a red bath, which could be madder, cochineal, kermes, or orchil. Since orchil is known to be very unstable to light, its potential use in the original recipe was investigated and a study on this dye was performed. Contactless analyses (hyperspectral imaging in the visible-near-infrared range and UV fluorescence spectroscopy) were carried out on both the tapestry and mock-ups prepared following various mediaeval recipes. The investigation allowed for the identification of woad and orchil on the back of the tapestry, which was preserved from exposure to light. In addition, an ageing study elucidated colour degradation, revealing not only the different responses to light of different dyes but also the effect of specific dye preparations on light resistance. The experiments showed that the longer the maceration, the higher the light resistance of the dye. Furthermore, the red orchil colour fades faster than the woad.

Abstract This study compares the adsorption behavior of both Methylene Blue (MB) and Congo Red (CR) dyes on the surfaces of cement kiln dust (CKD) powder from the experimentally simulated wastewater solution. The cement kiln dust powder was characterized using X-ray Fluorescence (XRF), X-ray diffraction (XRD), N2 adsorption–desorption Brunauer–Emmett–Teller (BET), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) tests. The adsorption for such dyes was studied under varying mixing contact times, temperatures, and pH as well as various initial concentrations of both dyes and adsorbent using the batch mode experiments. Pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were applied, and the results revealed that the pseudo-second-order fitted well to the kinetic data. Thermodynamic parameters stated that the adsorption process was endothermic. Studying Linear and nonlinear forms of Langmuir and Freundlich's adsorption isotherms revealed that the adsorption process was followed by both homogeneous mono-layer and heterogeneous multilayer coverage on the active sites of cement kiln dust particles. The data showed that the adsorption capacities of the methylene blue and Congo red dyes were 58.43 and 123.42 mg/g, respectively and cement kiln dust is an adsorbent with little cost for the treatment of wastewater.

To obtain high efficient elimination of ammonia (NH4+) from wastewater, Cu(II), Ni(II), and Co(II)) were loaded on Dowex-50WX8 resin (D-H) and studied their removal efficiency towards NH4+ from aqueous solutions. The adsorption capacity of Cu(II)-loaded on D-H (D-Cu2+) towards NH4+ (qe = 95.58 mg/g) was the highest one compared with that of D-Ni2+ (qe = 57.29 mg/g) and D-Co2+ (qe = 43.43 mg/g). Detailed studies focused on the removal of NH4+ utilizing D-Cu2+ were accomplished under various experimental conditions. The pseudo-second-order kinetic model fitted well the adsorption data of NH4+ on D-Cu2+. The non-linear Langmuir model was the best model for the adsorption process, producing a maximum equilibrium adsorption capacity (qmax = 280.9 mg/g) at pH = 8.4, and 303 K in less than 20 min. The adsorption of NH4+ onto D-Cu2+ was an exothermic and spontaneous process. In a sustainable step, the resulting D-Cu(II)-ammine composite from the NH4+ adsorption process displayed excellent catalytic activity for the degradation of aniline blue (AB) and methyl violet 2B (MV 2B) dyes utilizing H2O2 as an eco-friendly oxidant. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, a functionalized magnetic powder complex porous carbon derived from ZIF‐8 (ZIF‐8@Na‐Cit@Fe3O4NPs@AC(500°C)) was prepared and applied for the waste liquid containing MB, TC, and Cu2+ adsorption removal. The ZIF‐8@Na‐Cit@Fe3O4NPs@AC(500°C) perfectly inherited the feature of parent ZIF‐8, posed a high specific surface area (SBET = 812.73 m2 g−1), be rich in surface nitrogen functional groups, and resulting in a good dynamic adsorption of the MB, TC, and Cu2+. The ZIF‐8@Na‐Cit@Fe3O4NPs@AC(500°C) exhibited the best adsorption performance of high‐concentration waste liquid containing MB, TC, and Cu2+, with equilibrium adsorption capacity of MB (408 mg g−1), TC (417 mg g−1), and Cu2+ (386 mg g−1), respectively. The acetone and toluene adsorption were spontaneously and exothermic, given the negative values of free energy (ΔG) and enthalpy (ΔH). The difference of MB, TC, and Cu2+ adsorption on ZIF‐8@Na‐Cit@Fe3O4NPs@AC(500°C) attributed to the affinity difference (polarity and molecular diameter) and the nitrogen‐containing functional groups (π‐π interaction and electrostatic attraction). Therefore, it was found that ZIF‐8@Na‐Cit@Fe3O4NPs@AC(500°C) could effectively adsorb MB, TC, and Cu2+, and ZIF‐8@Na‐Cit@Fe3O4NPs@AC(500°C) could remove more than 70% of the above pollutants after repeated use for four times; it has a good application prospect. [ABSTRACT FROM AUTHOR]

The ability of algae to decolorize and remove synthetic dyes such as Congo red, methylene blue, rhodamine B, and remazol black dyes was investigated in this study. The tested algae showed increased efficiency for color degradation observed by UV spectral analysis. Chlorococcum sp. exhibited a very drastic reduction in absorbance on the 5th day, and the laccase enzyme production was also higher (533 U/ml) in Congo red treatment. The other tested dyes also showed limited degradation, but their absorbance dropped only after 10 days of treatment. Fourier-transform infrared spectroscopy (FTIR) analysis confirmed a significant shift in functional groups of control and treated samples. Furthermore, the Clarias gariepinus fish was acclimatized and was preceded for dye treatment. In the toxicity assessment of Congo red, the mortality rate of 100% was observed on the 8th day, whereas the algae-treated dye at 2 ppm showed only 40% mortality on the 20th day. Histopathological observations of the liver and kidney from sacrificed fishes revealed intense cellular damage in higher concentrations. In the experimental studies, 6 ppm of the dye had the least toxicity to tested fish cells (kidney and liver). The uniqueness and significance of the present investigation was to evaluate the toxicity of various concentrations of Congo red dye on fish by performing histological studies of internal organs, which made Chlorococcum sp. a potential candidate for dye effluent treatment. From the present study, it is evident that the investigated microalgae may serve as a better tool for industrial applications in safe toxicant removal from aquatic ecosystems. [ABSTRACT FROM AUTHOR]

The scientific community is becoming increasingly interested in the production of activated carbon (AC) using pyrolyzed biomass wastes as potential sustainable precursors. Both chemical and physical methods may have a significant impact on the chemical and physical properties of AC, making it suitable for a variety of applications such as water pollution treatment, CO2 capture, dye, and heavy metal (HM) removal, and energy storage. The properties of AC are significantly influenced by feedstock composition, pyrolysis conditions, and carbon activation parameters. In comparison to traditional AC, activated biochar appears to be a new potentially cost-effective, and environmentally friendly carbon material with a wide range of applications. Walnut is a well-known member of the Juglandaceae family. Walnut Shell (WS) is extremely tough and degrades very slowly, and the multiple synthesis procedures employ the shell to prepare AC. In this review article, a detailed list of products and different applications of AC from the WS is provided. The cited results explain the optimal conditions for an adsorption process, which include pH, adsorbent dosage, temperature, agitation speed, contact time, efficiency, adsorption capacity, fitting model, kinetics, and thermodynamics. In addition, it also describes the removal of a few organic compounds, and energy storage applications using parameters such as BET, different electrolytes, and specific capacitance. [ABSTRACT FROM AUTHOR]