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Presence of copying pencils in heritage objects poses a significant challenge for conservators due to their proneness to fading, sensitivity to solvents and difficulties in differentiation from regular graphite pencils. In this paper a method of copying pencils identification by means of ATR—FTIR spectroscopy is used. A protocol for spectra processing and dimensionality reduction of spectral data by means of principal component analysis has been developed, allowing for pencil types differentiation and providing an easy to read visual representation of the collected data. The protocol has been developed on mock-up samples and tested on objects from the archives of the State Museum Auschwitz – Birkenau. [ABSTRACT FROM AUTHOR]

Facile fabrication of flexible substrates containing high concentration of nanoparticles (NPs) is very promising owing to their capability of swab-based surface-enhanced Raman scattering (SERS) trace detection. However, the background signal of the substrate could compromise the trace-detection capabilities. Moreover, the presence of fluorescent molecules may result in intense fluorescence background which could overshadow the Raman peaks. Herein, we demonstrate that the surfactant-free bimetallic (Ag and Au) NPs, synthesized directly on the filter paper, are very effective in reducing the background signal in SERS-based trace detection. Simple soaking of filter paper in a mixture of HAuCl 4 and AgNO 3 solution, and its immediate drying and reduction produces Au-Ag alloy NPs on the filter paper. Interestingly, the substrates are very effective in quenching the background fluorescence of both filter paper and the analyte, thereby effectively detecting the SERS signature of the fluorescent molecules. In particular, Rhodamine6G (R6G) concentrations down to 10−10 M were detected under resonance excitation, both by solution drying and swabbing. The swab detection of ammonium nitrate, which is usually used in homemade explosives, was also demonstrated. Moreover, owing to the fluorescence quenching properties, the Au-Ag alloy substrates (AuAgS) were able to carry out the swab-based multiplex-detection of crystal violet (CV), Brilliant Cresyl Blue (BCB), and R6G upon resonance excitation of R6G. Finally, the substrates have shown good reproducibility, stability, and signal uniformity. This verifies the potential of AuAgS for real-world trace-detection applications. [ABSTRACT FROM AUTHOR]

One of the methods to solve the problem of lead metal in water is adsorption. One of the adsorbents that can be used is cellulose because it has an active group that can bind Pb(II). In this study, cellulose from the HVS wastepaper was used as the adsorbent to adsorb the Pb metal. HVS wastepaper was extracted with 10% w/v NaHCO3 and refluxed with 5% w/v Na2HPO4. Cellulose was characterized using Fourier Transforms Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). Pb(II) adsorption was carried out by the batch method, and it was evaluated using Atomic Absorption Spectrophotometry (AAS) with varying adsorbent mass, concentration, contact time, and pH. FTIR characterization showed that the presence of O - H, C - H, C = O, and C - O groups played a role in the adsorption process. The surface morphology of cellulose from SEM analysis showed form like a fiber shape with agglomerated fine particles. The optimum conditions for adsorption were 0.100 g of adsorbent mass, Pb(II) concentration of 105 ppm, contact time of 10 minutes, and pH of solution 5. An adsorption isotherm model that is preferable for this adsorption process is the Freundlich isotherm model. From the results of this study, HVS paper waste can be used as an adsorbent to handle Pb(II) metal ions to be an alternative as a lowcost adsorbent. [ABSTRACT FROM AUTHOR]

We present a tilted fiber Bragg grating (TFBG) sensor coated with crystal violet/perfluorinated sulfonic acid (CV/Nafion) composite film for relative humidity (RH) monitoring. The composite film demonstrates the characteristics of an optical "humidity test paper" by exhibiting a color transition from yellow to green within a RH range of 10 % to 80 %. This color variation indicates its potential to effectively monitor RH levels in diverse environments. To achieve a quantitative RH sensing, we coat CV/Nafion composite film on an etched TFBG (ETFBG), where surrounding RH changes can be measured from spectral responses of ETFBG transmission. In experiments, the proposed the CV/Nafion-coated ETFBG sensor exhibits RH sensitivities of 0.068 dB/%RH and 3 pm/%RH for intensity change and wavelength shift measurements, respectively, within a relative humidity (RH) range of 10 % to 80 %. Additionally, based on intensity measurement, short response and recovery times of ∼4.4 and ∼4.6 s are estimated from a continuous RH monitoring. • The proposed sensor's color will change from yellow to green with the increasing of the RH. • The proposed sensor could be used for RH detection of liquids, gases, and solids. • High RH detection sensitivity of 0.068 dB/% RH was obtained. • The response and recovery times are 4.4 s and 4.6 s respectively. [ABSTRACT FROM AUTHOR]

Gamma radiations are known to bring about radiolysis of myriad compounds / dyes which is used to measure of the energy of the incident radiation on the system. The use of various dye solutions for chemical dosimetry is reported in literature. Various thin film dosimeters, semi-conductor dosimeters are also reported and widely used. Similarly ? - dose quantification using paper or polymer impregnated with dyes has also been reported. In the present study, decolouration due to gamma radiation of various dye impregnated papers viz. Gentian Violet (GV), Malachite Blue (MB), Malachite Green (MG), Brilliant Yellow (BY) and Congo Red (CR) has been investigated using device independent colour parameters. The colour analysis was done by standard procedures of Commission Internationale de l'Eclairage CIE. Color has mind dependency so to eliminate the errors in determination colour parameters are evaluated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Inkjet printing Ag nanoparticles on paper coated with chitosan or N,N, N -trimethyl chitosan to obtain SERS substrates. • Biopolymer coatings not only reduce the rugosity and porosity of the paper but also confer hydrophobicity to the paper. • SERS sensitivity and reproducibility was improved when compared with non-coated counterparts. Paper-based sensors for surface-enhanced Raman scattering (SERS) detection of water pollutants have gained much attention in the last decades. However, most of the fabricated paper-based SERS substrates still face some limitations regarding reproducibility and uniformity. In this work, we report the fabrication of hydrophobic paper-based SERS substrates with high reproducibility and uniformity by inkjet printing Ag colloidal nanoparticles (NPs) on office paper pre-treated with chitosan (CH) or N,N, N -trimethyl chitosan (TMC). We demonstrate that the previous coating of paper with such biopolymers substantially improves the SERS performance of the paper substrates. In screening experiments, crystal violet (CV) 100 μM was used as molecular probe, leading to an increase of about 9- and 7-fold in the observed SERS intensity when the papers were coated with CH and TMC, respectively. Also, the reproducibility of the substrates coated with the biopolymers increased more than 2 times compared to non-coated office paper. We suggest that the improved performance of the coated substrates is related to a more uniform deposition of the AgNPs on the paper surface due to the hydrophobic nature, low porosity and roughness of the coated paper. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the activity, resistance, clonality of MIC distribution, and the correlation between virulence and resistance genes and biofilm formation of omadacycline (OMC) in clinics for Streptococcus agalactiae isolates from China. 162 isolates were collected retrospectively in China. The S. agalactiae were collected from the body's cervical secretions, wound secretions, ear swabs, secretions, semen, venous blood, cerebrospinal fluid, pee, etc. The MIC of OMC against S. agalactiae was determined by broth microdilution. The inhibition zone diameters of OMC and other common antibiotics were measured using filter paper. D-test was performed to determine the phenotype of cross resistance between erythromycin and clindamycin. In Multilocus sequence typing (MLST), some commonly-detected resistance genes and virulence gene of these S. agalactiae isolates were investigated using polymerase chain reaction (PCR). Biofilms were detected by crystal violet staining. Our data demonstrated the correalation of the biofilm formation and OMA antimicrobial susceptibility of S.agalactiae clinical isolates with the carrier of virulence gene scpB. Conclusively, OMC exhibits the robust antimcirobial activity against clinical S. agalactiae isolates from China compared with DOX or MIN, and the carrier of the virulence gene scpB might correlate with the biofilm formation in OMC-resistant S. agalactiae. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate a seeded approach for in-situ growth of Ag nanostructures directly on filter paper. Multiple growth steps were used to increase the size of Ag NPs grown from Au seeds. Essentially, this procedure generated a high density of NPs on filter paper which in turn provided high enhancement of Raman signals. We have seen a marked increase in the SERS enhancement factor with each growth step. Moreover, the relative standard deviation (RSD) values decreased with each growth step, indicating the relatively uniform distribution of NPs on the substrate. With four growth steps, we were able to achieve an EF of 9.28 × 104 with RSD values of 14%. In particular, the detection limit of 10 nM for CV has been achieved by both solution drying and swabbing. Moreover, swab detection of explosive material ammonium nitrate down to 100 µM has also been demonstrated. [ABSTRACT FROM AUTHOR]

In this paper, a NiAl-LDH with the characteristic structure of a hydrotalc-like compound was applied as a carrier in a two-step hydrothermal process, and a MnCdS/In2S3/NiAl-LDH composite material was successfully prepared by loading MnCdS and In2S3 on the flower spherical-like surface of NiAl-LDH. The combination of NiAl-LDH with In2S3 and MnCdS made the band gap smaller and the light absorption range larger, thus increasing the utilization rate of light. 50% MnCdS/In2S3/NiAl-LDH composites had the best photoinduced charge separation and highest surface enrichment of photogenerated electrons. In the degradation experiment of crystal violet (CV), 50% MnCdS/In2S3/NiAl-LDH composites showed superior photocatalytic degradation efficiency (>98.5%) under full spectrum light. Furthermore, the applicability and universality of photocatalysts were studied by observing the degradation of CV by MnCdS/In2S3/NiAl-LDH composites under different conditions. In addition, the composites showed excellent hydrogen production capacity in the photolysis of water, in which hydrogen production within 8 hours was about 7661.51 μmol g−1. By combining the results of active species capture experiments, density functional theory (DFT) calculations and photoelectrochemical experiments, the possible mechanism of double S-scheme heterojunction photocatalysis among NiAl-LDH, In2S3 and MnCdS was inferred, which is one of the main reasons for the enhancement of photocatalytic activity. [ABSTRACT FROM AUTHOR]

The crystal violet (CV) staining technique represents a prevalent approach for the development of latent fingerprints, especially on adhesive tape surfaces. Nevertheless, the technique necessitates intricate formulations to augment its performance. In this investigation, an optimized CV staining protocol was developed, characterized by the absence of residual dye on the target substrates and the capability of facilitating fingerprint visualization under ambient light conditions. Four donors, comprising two males and two females, deposited natural fingerprints on various substrates, including glass microscope slides, aluminum foil, and 115 g glossy coated paper, without any specific guidelines. Fingerprints developed using cyanoacrylate fuming served as benchmarks and were contrasted with those generated through alternative methods: CV, ardrox, rhodamine 6G, powdering, and the optimized CV staining protocol. The fingerprint development experiment was replicated at seven distinct time intervals, encompassing 1 day, 1 week, 1, 3, 6, 9, and 12 months, resulting in a dataset of 420 fingerprints. The evaluation of fingerprint identifiability employed a scoring system established by the Home Office Centre for Applied Science and Technology. The results indicated that the optimized CV staining technique demonstrated superior performance, boasting a 92.9% rate of identifiable fingerprint development in contrast to other employed methodologies. Consequently, this optimized CV staining approach is recommended as an efficient, rapid, and straightforward critical dyeing method, applicable to a wide array of substrates in forensic investigations. [ABSTRACT FROM AUTHOR]

Insufficient dental restoration finishing and polishing may lead to plaque accumulation, gingival inflammation, staining, caries, and esthetic impairment. Here, the effect of two finishing and polishing systems on surface roughness and bacterial adhesion were evaluated. Two finishing and polishing kits were evaluated: diamond burs (Shine 1-2, Strauss & Co, Raanana, Israel) and paper discs (Sof-Lex 3M ESPE, Seefeld, Germany) (n = 30 each). For each group surface roughness was evaluated using an optical profilometer (Contour GT-K1, Bruker, Billerica, MA, USA) (n = 10). Surface bacteria were evaluated for biofilm biomass using crystal violet (CV) staining (absorbance measured at 538 nm) and viable counts (CFU/mL) (n = 20). The control group included polymerized discs against a Mylar strip (n = 30). Student's t test and one-way ANOVA were used for statistical evaluation. Diamond burs, paper discs, and control average surface RA were 169.4 ± 45.2 µ, 364 ± 77.7 µ, and 121.2 ± 18.1 µ, respectively. There was a significant difference found between all groups (p < 0.00001). Bacterial biomass on diamond burs, paper discs, and control samples were 0.458 ± 0.161, 0.507 ± 0.139, and 0.446 ± 0.142, respectively (p = 0.257). Viable bacterial counts (CFU/mL) on diamond burs, paper discs, and control samples were 2.25 × 104, 2.95 × 104, and 2.75 × 104, respectively (p = 0.856). A comparison between two finishing and polishing kits showed that the shine 1–2 diamond bur kit produced a smoother surface than the polishing disc kit. No differences were found in the biofilm biomass quantification and bacterial viable count between the groups. [ABSTRACT FROM AUTHOR]

In the former section of the present paper, the prospective application of B. mojavensis BI2 derived lipopeptides for dyes biodecolorization was demonstrated. The lipopeptide was mainly composed of linear and cyclic Fengycin and Surfactin isoforms. When using 100 mg/L, we are able to remove about 98% of 100 and 200 mg/L Malachite Green (MG). For the Crystal Violet (CV), the % of biodecolorization does not exceed 85% in the presence of 100 and 400 mg/L BI2 lipopeptide. In the second part of the paper, we proved the efficiency of dyes biosorption by palm waste floor, optimized by a Taguichi design. The bio-treatment efficiency was evaluated by color removal and the enhancement of germination index. Optimum treatments were obtained with 10 g/L and 6 g/L palm waste for 200 mg/L MG and CV respectively during 1 hour. Nevertheless, BI2 lipopeptide addition has no significant effect on color biosorption by date palm waste flour. [ABSTRACT FROM AUTHOR]

Industrial dyes are considered one of the main causes of increased water pollution of water. Many businesses, such as steel and paper, are located along riverbanks because they require large amounts of water in their manufacturing processes, and their wastes, which contain acids, alkalis, dyes, and other chemicals, are dumped and poured into rivers as effluents. For example, chemical enterprises producing aluminum emit a significant quantity of fluoride into the air and effluents into water bodies. Fertilizer facilities produce a lot of ammonia, whereas steel plants produce cyanide. Many nations consider employing wastewater treatment plants using physical, biological, and chemical methods to clean the wastewater to address environmental crises. The treated water can be used for targeting the irrigation systems in its majority, as it is biologically acceptable for that specific use, industrial dyes are considered one of the leading causes of increased water pollution of water. Many businesses, such as steel and paper, are located along riverbanks because they require large amounts of water in their manufacturing processes, and their wastes, which contain acids, alkalis, dyes, and other chemicals, are dumped and poured into rivers as effluents. For example, chemical enterprises producing aluminum emit a significant quantity of fluoride into the air and effluents into water bodies. Fertilizer facilities produce much ammonia, whereas steel plants produce cyanide. Chromium salts are used in. Many nations consider employing wastewater treatment plants using physical, biological, and chemical methods to clean the wastewater to address environmental crises. The treated water can target the majority of irrigation systems, as it is biologically acceptable for that specific use, which economizes the use of freshwater sources for municipal use. This study presents a novel method for fabricating an efficient adsorbent sheet for wastewater treatment. The sheets are fabricated by combining sugarcane bagasse pulp as a scaffold with commercial, naturally activated carbon, and bimetallic‐prepared adsorbents. Sugarcane bagasse is utilized in producing activated carbon because of its high carbon contents, availability, and low cost. The prepared composite sheets are synthesized and investigated for pollutants removal of crystal violet (CV), methyl orange (MO), and Chromium (CI) dyes. Different weight ratios of activated carbon are used to form a bio‐composite mixed sheet. The formed sheets' morphology is performed via a high scanning electron microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). To determine the adsorption mechanism, the intra‐particle diffuse screening experiment is used to test the experimental data. All the prepared sheets can retain the pollutants, with the best removal efficiency of 98% for methyl orange adsorption onto the bio‐composite mixed sheet. The results of the parameter (time, concentration, and dose) sets provided valuable proof that the adsorption of methyl orange onto the bio‐composite sheet mixed with naturally activated carbon is an endothermic phenomenon involving physical adsorption. [ABSTRACT FROM AUTHOR]

This Special Issue includes 12 research papers on the development of various materials for adsorbing different contaminants in water, such as Sb, Cr(VI), Cu(II), Zn(II), fluorine, phenol, dyes (indigo carmine, Congo red, methylene blue, and crystal violet), and drugs (dlevofloxacin, captopril, and diclofenac, and paracetamol). The commercial, natural, and synthetic materials used as adsorbents comprise commercial activated carbon, natural clay and montmorillonite, biosorbent based on sugarcane bagasse or algal, graphene oxide, graphene oxide-based magnetic nanomaterial, mesoporous Zr-G-C3N4 nanomaterial, nitrogen-doped core–shell mesoporous carbonaceous nano-sphere, magnetic Fe-C-N composite, polyaniline-immobilized ZnO nanorod, and hydroxy-iron/acid–base-modified sepiolite composite. Various operational conditions are evaluated under batch adsorption experiments, such as pH, NaCl, solid/liquid ratio, stirring speed, contact time, solution temperature, initial adsorbate concentration. The re-usability of laden materials is evaluated through adsorption–desorption cycles. Adsorption kinetics, isotherm, thermodynamics, and mechanisms are studied and discussed. Machine learning processes and statistical physics models are also applied in the field of adsorption science and technology. [ABSTRACT FROM AUTHOR]

Building an optical filtration function into a microfluidic chip is a promising way of simplifying the optical detection system of a microfluidic device. In this paper, a PDMS microfluidic chip filter that is capable of transmitting chlorophyll fluorescence and blocking interfering light in the visible wavelength range was developed for living algae detection with a smartphone. The chip was fabricated by sealing a layer of crystal violet solution in a PDMS layer on the top of the Sudan II-doped PDMS slab, which has a straight microchannel. Optimum dye concentrations and thicknesses for the crystal violet solution layer and Sudan II-doped PDMS slab were investigated and determined by spectrum measurements. It was found that the cut-on range of this integrated microfluidic chip is extended to about 625 nm and the transmittance in the chlorophyll fluorescence range (650 nm to 710 nm) is as high as 95%, when 25 mg L−1 Sudan II-doped PDMS slab (with a 3 mm thickness) and 2 mg L−1 crystal violet solution (with a 0.3 mm thickness) were used. Living algae detection using this chlorophyll-fluorescence-filtering PDMS microfluidic chip and a smartphone-based imaging platform was achieved, and the results compared favorably with those using a commercial filter. [ABSTRACT FROM AUTHOR]

Environmental monitoring, environmental remediation, microbiotechnology, wastewater treatment, modeling design Meanwhile, other papers also included the studies on modeling design, pollutant degradation and greenhouse gas emissions, which also covered water, soil and constructed wetlands involved with microorganisms. Keywords: environmental monitoring; environmental remediation; microbiotechnology; wastewater treatment; modeling design EN environmental monitoring environmental remediation microbiotechnology wastewater treatment modeling design 1 3 3 05/17/22 20220513 NES 220513 With the continuous improvement of the level of scientific and technological innovation, many emerging materials and chemicals have come into our lives, which has brought great pressure to the environment and caused an increasing number of contamination problems (Atashgahi et al., [2]; Escher Beate et al., [3]; Johnson Andrew et al., [4]). [Extracted from the article]

The present paper focused on synthesizing a polyacrylamide-titanium dioxide (PAA@TiO2) nanocomposite using a cross-linking method with N, N′-methylenebisacrylamide and then using this composite to eliminate crystal violet (CV) dye from water and to characterize the adsorbent by XRD, FT-IR, and SEM-EDX techniques. The characterization revealed that TiO2 nanoparticles dispersed homogeneously within the polymer matrix. The maximum amount of adsorption was about 38.9 mg g−1 under the adsorbent dose of 5 g L−1, 500 mg L−1 CV dye concentration, and pH 6.9. The interaction between the CV molecule and the PAA@TiO2 nanocomposite surface was studied using Monte Carlo (MC) and molecular dynamics (MD) simulations. The negative value of the Eads (− 586.56 kcal mol−1) of the CV molecules onto the PAA@TiO2 nanocomposite surface gives credibility to the experimental results. All obtained results showed that PAA@TiO2 hybrid polymer nanocomposite could be an alternative adsorbent for crystal violet dye removal from wastewater. [ABSTRACT FROM AUTHOR]

This paper's purpose was to evaluate the interaction between three imidazole derivatives, (2-methyl-1H-imidazol-1-yl)methanol (SAM3), 1,1′-methanediylbis(1H-benzimidazole (AM5) and (1H-benzo[d]imidazol-1-yl)methanol 1-hydroxymethylbenzimidazole (SAM5) on the one hand, and sodium dodecyl sulphate (SDS) on the other, as antifungal combinations against Candida spp. Inhibitory activity was assessed using the agar diffusion method and Minimal Inhibitory Concentration (MIC) and showed moderate inhibitory activity of single imidazole derivatives against Candida spp. The mean value of MIC ranged from 200 µg/mL (SAM3) to 312.5 µg/mL (SAM3), while for SDS the MIC was around 1000 µg/mL. When used in combination with SDS, the imidazole derivatives demonstrated an improvement in their antifungal activity. Their MIC decreased over five times for AM5 and over seven times for SAM3 and SAM5, respectively, and ranged from 26.56 µg/mL (SAM3) to 53.90 µg/mL (AM5). Most combinations displayed an additive effect while a clear synergistic effect was recorded in only a few cases. Thus, the FIC Index (FICI) with values between 0.311 and 0.375 showed a synergistic effect against Candida spp. when SDS was associated with SAM3 (three strains), SAM5 (two strains) and AM5 (one strain). The association of imidazole derivatives with SDS led to the increased release of cellular material as well as the intracellular influx of crystal violet (CV), which indicated an alteration of the membrane permeability of Candida spp. cells. This favored the synergistic effect via increasing the intracellular influx of imidazoles. [ABSTRACT FROM AUTHOR]

Escherichia coli is an important bacterium for preventing food poisoning and biofilm infections. The emergence of antibiotic-resistant microorganisms necessitates the development of new antibiotics. The formation of bacterial biofilm is a drug-resistance mechanism utilized by diverse microorganisms. Therefore, it is important to identify compounds that can inhibit biofilm formation and cell survival, without triggering drug resistance. Herein, the antibacterial and antibiofilm activities of 2 types of Thai propolis (collected from Chiang Mai and Chanthaburi) against E. coli were investigated. The antibacterial activity was evaluated using the paper-disc method, while the minimum inhibitory concentration assay was performed using 2-fold serial dilution. Both types of Thai propolis and their isolated compounds showed antibacterial activity against E. coli (minimum inhibitory concentration: 32 µg/mL). The biofilm growth and development were assessed using a crystal violet solution. In particular, the extracts of the Chiang Mai propolis exhibited a significant antibiofilm formation activity against E. coli. Four prenylflavonoids, present in high proportions in the Chiang Mai propolis extracts, inhibited biofilm formation at low concentrations, contributing to the overall antibiofilm activity. These findings indicate that Thai propolis, a natural product, exhibits antibacterial and antibiofilm activities against E. coli. [ABSTRACT FROM AUTHOR]

In this paper, 4‐aminosalicylic acid functionalized multiwalled carbon nanotubes (CNT‐ASA) filled in a mini‐column and attached to a Flow‐injection system for the adsorptive removal of Crystal violet (CV) dye was employed. The remaining CV concentration was detected by a UV‐Visible Spectrophotometric method, which is proposed in this paper. The factors influencing the adsorption and desorption of CV, such as pH, eluent, sample and eluent flow rates were optimized. The optimum pH was 5.5, the eluent selected for desorption was 1 N acetic acid: ethanol (8 : 2), and the sample and eluent flow rate were both 5 mL min−1. Under the optimum conditions, the results obtained showed that CNT‐ASA possessed excellent dye removal efficiency of ∼99 % and adsorption capacity of 440 mg g−1 for CV. The advantage of using the flow‐injection system is the faster adsorption process (in just 1 minute), less amount and high reuse of the nano‐adsorbent, which is better in comparison to the traditional column method. The proposed method was applied on industrial and river water samples and good recovery (99–105 %) was obtained. Hence, it can be concluded that the proposed method is fast, effective, and can be applied on large‐scale wastewater treatment. [ABSTRACT FROM AUTHOR]

In this paper, Fe3O4 magnetic nanoparticles (Fe3O4 NPs) were successfully synthesised and dispersed on alfalfa to prepare Fe3O4/alfalfa nanocomposite for cationic dye removal from aqueous solutions. Characterisation of Fe3O4/alfalfa nanocomposite using FT-IR, FESEM, and EDX analyses showed that the Fe3O4 NPs were excellently dispersed on alfalfa. The results display that the Fe3O4/alfalfa as a green adsorbent have high removal ability for toxic cationic dyes, such as malachite green (MG) and crystal violet (CV). For Fe3O4-alfalfa, the average particle size of nanoparticles on alfalfa (around 20–30 nm) has decreased compared with alone Fe3O4. The experiments showed that the adsorption of dyes onto Fe3O4-alfalfa better described with pseudo-second-order kinetic and Freundlich isotherm models, suggesting the surface heterogeneity of the Fe3O4/alfalfa. Furthermore, Fe3O4-alfalfa with adsorption capacity of 62.68 mgg−1 and 55.12 mgg−1 towards MG and CV, respectively, was comparable with those of the reported adsorbents. The results indicated that the adsorption of both dyes onto Fe3O4-alfalfa was thermodynamically spontaneous and more favourable at lower temperatures. The results also confirmed that the removal of MG and CV by Fe3O4-alfalfa were remarkable after reusing five times. Therefore, the Fe3O4-alfalfa as a green and low-cost nanoadsorbent with an easy synthesis route could be used for purification of water and wastewater contaminated by pollutants. [ABSTRACT FROM AUTHOR]

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The combination of two compounds with known antimicrobial activity may, in some cases, be an effective way to limit the resistance to antibiotics of specific pathogens. Molecules carrying pyrazole moiety are well known for their bioactive properties and have wide applicability in the medical and pharmaceutical field. Surfactants have, among other useful properties, the ability to affect the growth of microorganisms. The paper reports on the effect of the combination of two pyrazole derivatives, (1H-pyrazol-1-yl) methanol 1-hydroxymethylpyrazole (SAM1) and 1,1′methandiylbis (1H–pyrazol) (AM1), with sorbitan monolaurate (polysorbate 21, Tween 21, T21) on the growth of Gram-positive and Gram-negative bacteria. The results demonstrated a different ability of this combination to inhibit Staphylococcus aureus and Escherichia coli. T21 intensified the inhibitory activity of the pyrazoles to a greater extent in the Gram-negative bacteria compared to the Gram-positive ones, a fact confirmed by time-kill experiments. The experimental data showed that the association of T21 with the pyrazoles led to the increased release of intracellular material and a more intense uptake of crystal violet, which indicates that the potentiation of the antibacterial effect was based on the modification of the normal permeability of bacterial cells. T21 acted as a modulating factor and increased the permeability of the membrane, allowing the accelerated penetration of the pyrazoles inside the bacterial cells. This fact is important in controlling the global increase in microbial resistance to antibiotics and antimicrobials and finding viable solutions to overcome the antibiotic crisis. The paper highlights the possibility of using non-toxic surfactant molecules in antimicrobial combinations with practical applications. This could widen the range of adjuvants in applications which would be useful in the control of resistant microorganisms. [ABSTRACT FROM AUTHOR]

In this paper, the novel ECL sensor of the 6‐methoxychromone (6‐MC)/S2O82− system was designed by using 2‐naphthalene sulfonic acid (2‐NSA) as a co‐reaction accelerator. Fluorescence, ECL spectrum, and cyclic voltammetry (CV) were used to explore extensively the ECL mechanism of the system. It is worth pointing out that 2‐naphthalene sulfonic acid (2‐NSA) was first proposed as a co‐reaction accelerator, reacting with the coreactant K2S2O8 rather than the luminophore, promoting the generation of additional oxidant SO4− from S2O82−, thus amplifying the ECL signal. Furthermore, under the optimal experimental conditions, the high sensitivity of the 2‐naphthalene sulfonic acid (2‐NSA)+6‐methoxychromone (6‐MC)/S2O82− system was realized for the detection of methyl violet (MV) in the linear range of 10−8~10−2 M, with a detection limit of 5.14×10−10 M. In addition, this find offers some guidance for further developing co‐reaction accelerators with excellent performance in the future. [ABSTRACT FROM AUTHOR]

Developing synthetic strategies for smart materials for the adsorption and separation of toxic chemicals is of great importance. Metal–organic frameworks (MOFs) have been proven to be outstanding adsorbent materials that possess excellent pollutant removal performances in wastewater treatment, including dye recycling. In this work, a neutral Cd(II) based 2D framework with a dual ligand strategy involving –OH functionalized 5-hydroxyisophthalic acid (5-OH-H2IPA) and the amide decorated Schiff base ligand (E)-N′-(pyridin-4-ylmethylene)isonicotinohydrazide (L) has been synthesized by different synthetic routes and characterized by various analytical methods. Thus, crystals of {[Cd(5-OH-IPA)(L)]·CH3OH}n synthesized via diffusion (ADES-7D) and the phase pure bulk product synthesized by conventional reflux (ADES-7C) and the mechanochemical grinding method (ADES-7M) have been established using PXRD data of the respective product showing identical simulated SXRD data to those of ADES-7D. The mechanochemically synthesized ADES-7M possesses a better surface area and CO2 adsorption capability compared to ADES-7C, which is also supported by electron microscopy and particle size measurements. Furthermore, ADES-7 can be used as an efficient adsorbent material for the reversible, selective adsorption (42–99%) and separation of the cationic dyes malachite green (MG), methyl violet (MV), methylene blue (MB), and rhodamine B (RhB) from the mixture of cationic/anionic dyes (methyl orange (MO) and bromocresol green (BCG)) in the aqueous phase. Specifically, ADES-7M possesses better dye capture capability compared to ADES-7C, even in the case of the bigger dye RhB with adsorption differences of 2.38 to 1.01 mg g−1, respectively. The dye adsorption kinetics follows pseudo-second-order kinetics, and the dye adsorption isotherm fits well with the Langmuir/Freundlich adsorption isotherm models. The probable mechanism of adsorption involving the supramolecular interaction between the host MOF and the guest dye has also been proposed. [ABSTRACT FROM AUTHOR]

The thermal decomposition or even explosion of nitrocellulose during long-term storage is prevented by adding stabilizers to nitrocellulose-based propellants. A series of novel arylmalonamide[70]fullerocyclopropane (3a–c) were synthesized through Bingel reaction. The molecular structures of 3a–c were verified through 1H NMR, 13C NMR, Fourier transform infrared spectroscopy (FT-IR), UV–visible spectroscopy, and mass spectrum. The thermal stability of 3a–c to nitrocellulose was studied by methyl violet paper test and iso-thermogravimetry method, and the results showed that the stability of 3a–c to nitrocellulose was significantly better than that of the [60]fullerene-based stabilizers. The thermal stability of 3a–c to nitrocellulose improved as the increase of the carbon chain length on the p-position of the benzene ring. The effects of 3a–c on the thermal decomposition of nitrocellulose were obtained by differential thermal analysis, and the results showed that the critical temperature of the thermal explosion of nitrocellulose can be increased by 0.1–2.8 °C by 3a–c. The thermal stability of 3a–c to nitrocellulose in adiabatic environment was confirmed by accelerating rate calorimetry. In addition, the stabilization mechanism was studied through ESR and FT-IR, and the results showed that 3a–c can react with nitrogen oxide radicals released by nitrocellulose. These arylmalonamide[70]fullerocyclopropane with excellent thermal stability and strong radical scavenging ability can be used as a promising stabilizer for single and double based propellants. [ABSTRACT FROM AUTHOR]

In this research paper, various formulations of zeolite‐loaded carboxymethyl tamarind kernel gum (CMTKG) based hydrogels were synthesized and utilized as a potential adsorbent for the removal of crystal violet (CV) dye. The swelling capacity of all the synthesized hydrogels was investigated and the composition of hydrogel which exhibited maximum swelling was used for the characterization and dye removal experiment. The CV dye was chosen as a model dye for the dye removal experiment. The structure of zeolite and zeolite embedded hydrogel was elucidated by XRD, FTIR, FE‐SEM, EDX and elemental papping techniques. The adsorption experiment was investigated by varying the CV concentration, amount of hydrogel adsorbent, temperature, pH of the dye solution, adsorption time, and ionic strength. The Langmuir and Freundlich isotherm models were used to fit the adsorption data and it was observed that the data fitted well with the Langmuir model. Moreover, hydrogel's maximum dye adsorption efficiency was found at 123.60 mg g−1. The adsorption kinetic studies were followed by pseudo‐ first‐order and intraparticle diffusion kinetic models. In addition, regeneration studies were performed for the best adsorbent hydrogel using ethanol solvent and the result concluded the desorption efficiency of hydrogel (82 %) over four desorption cycles. [ABSTRACT FROM AUTHOR]

An excessive accumulation of crystal violet dye in the human body results in an accelerated heart rate, tetraplegia, eye irritation, and long-term damage to the transparent mucous membrane that protects the eyeballs. Accordingly, in this paper, sodium manganese silicate/sodium manganese silicate hydroxide hydrate was easily fabricated as a novel type of nanostructures for the successful disposal of crystal violet dye from aqueous solutions. The formed sodium manganese silicate/sodium manganese silicate hydroxide hydrate nanostructures after the hydrothermal treatment of the gel produced from the interaction of Mn(II) ions with Si(IV) ions at 180 °C for 6, 12, 18, and 24 h were abbreviated as MS1, MS2, MS3, and MS4, respectively. The XRD showed that the average crystallite size of the MS1, MS2, MS3, and MS4 samples is 8.38, 7.43, 4.25, and 8.76 nm, respectively. The BET surface area of the MS1, MS2, MS3, and MS4 samples is 41.58, 46.15, 58.25, and 39.69 m2/g, respectively. The MS1, MS2, MS3, and MS4 samples consist of spherical and irregular shapes with average grain sizes of 157.22, 88.06, 43.75, and 107.08 nm, respectively. The best adsorption conditions of the crystal violet dye employing the MS1, MS2, MS3, and MS4 products were achieved at pH = 8, contact time = 140 min, and solution temperature = 298 kelvin. The linear pseudo-2nd-order model as well as the linear Langmuir isotherm better describe the disposal of the crystal violet dye using the MS1, MS2, MS3, and MS4 adsorbents. The studied thermodynamic parameters indicated that the disposal of the crystal violet dye employing the MS1, MS2, MS3, and MS4 adsorbents is spontaneous, exothermic, and chemical. The maximum disposal capacities of the MS1, MS2, MS3, and MS4 adsorbents towards crystal violet dye are 342.47, 362.32, 411.52, and 310.56 mg/g, respectively. [ABSTRACT FROM AUTHOR]

Silver chalcogenide quantum dots (QDs) are potential nanosensors for biological and environmental applications. These QDs present low toxicity and their narrow band gap makes them promising as near-infrared (NIR) photoluminescence (PL) probes, exhibiting images with higher penetrability. In addition, hydrophilicity is essential for applications in biological systems as well as detection in aqueous media. Using the same methodology, variations in synthesis conditions can alter the efficiency and performance of their intrinsic properties. Most studies seek the best conditions for each experimental variable in a univariate manner; however, multivariate strategies are a faster and more economical way to achieve this goal. Thus, in this work, we utilized chemometric approaches to enhance the NIR-II PL properties of Ag2Se QDs stabilized with 3-mercaptopropionic acid (MPA). Three experimental designs were used, totaling 58 syntheses, showing that the Ag2Se–MPA QDs, obtained under the conditions of [Ag+] of 2.5 mmol L−1, Ag : Se molar ratio of 8 : 1, MPA : Ag molar ratio of 6 : 1, heating at 70 °C, pH 10, and 180 min, presented the best emission profile with a maximum at 1070 nm and a FWHM of approximately 140 nm. The nanocrystals presented an average diameter of 6 nm and the orthorhombic crystalline phase. Preliminary surface-enhanced infrared absorption (SEIRA) spectroscopy assays were carried out for the detection of methyl violet 2B (MV) dye using these QDs. The enhancement factor obtained was higher than 3.5, which is comparable to those observed for other systems, namely Ag2Se-MSA QDs. These results showed the potential of the Ag2Se–MPA QDs for (bio)sensing applications. [ABSTRACT FROM AUTHOR]

Zinc metal–organic frameworks (Zn-MOFs) of phthalic acid (ZnPA) and nitro-phthalic acid (ZnNPA) microcrystalline particles were fabricated and utilized for the removal of organic cationic dyes (crystal violet (CV), methylene blue (MB) and rhodamine B (RhB)) from water. PXRD studies confirmed the formation of crystalline materials, and BET indicated the mesoporous structure. HR-SEM studies showed the rod and plate morphologies for ZnPA and ZnNPA, respectively. ZnPA revealed low adsorption of dyes (CV, 20%) whereas ZnNPA showed significantly enhanced dye adsorption (CV, 99%). In particular, ZnNPA exhibited higher adsorption of CV (99%) and MB dye (83%) compared to RhB (54%). Nevertheless, ZnNPA could not be reused due to strong adsorption of dyes. Hence, a natural binder was introduced by dipping ZnNPA into tea extract, which also showed high adsorption of CV and MB dyes. Kinetics of adsorption exhibited best fitting with the pseudo-second-order model, indicating strong interactions between the dyes and adsorbent. Adsorption isotherm fitting suggested a good correlation coefficient (R2) with the Freundlich model, suggesting multi-layer adsorption. Interestingly, ZnNPA showed high adsorption of CV and MB dyes across the pH range between 3.0 and 11.0. The binder-introduced ZnNPA adsorbent was easily regenerated and demonstrated three cycles of reusability without significant change in the dye adsorption. Thus, the present work indicated the role of functional groups in the ligand and binder for improving the dye adsorption characteristics of MOFs. [ABSTRACT FROM AUTHOR]

Three-dimensional iodoargentate hybrids [Co(en)3(Ag2I4)]n (1), [Fe(en)3(Ag2I4)]n (2) (en = ethylenediamine) and [Co(dien)2(Ag2I4)]n·nH2O (3) (dien = diethylenetriamine) were prepared in C2H5OH solvent via a one-step reaction under solvothermal conditions. In compounds 1 and 2, AgI4 tetrahedra were interlinked via corner-sharing to form a 3D α-Ag2I4 framework with interpenetrated channels with cross sectional dimensions of 8.071 Å × 9.039 Å and 9.039 Å × 9.039 Å. The AgI4 tetrahedra in compound 3 were connected via both corner- and edge-sharing into a 3D β-Ag2I4 framework with dimensions of 5.929 Å × 8.329 Å, and 8.329 Å × 9.910 Å. Compounds 1–3 showed sensitive photocurrent response under visible light irradiation with steady current densities in the range of 3.46–8.26 μA cm−2. These compounds were catalytically active during the photodegradation of crystal violet (CV), with degradation conversions of 72.2%, 91.5% and 80.1% after 105 min of light irradiation over compounds 1–3, respectively. [ABSTRACT FROM AUTHOR]

Harnessing solar energy using semiconductor-based materials to generate charge pairs to effectively drive photo-redox reactions has been envisioned as a promising approach toward a sustainable future. In this arena, the metal sulfide nanoparticles have demonstrated excellent performance in photomineralizing colored matter. However, their small surface area and relatively slow charge transfer has limited their practical applications. Therefore, for the effective mineralization of colored matter, we devise and construct the Sn2S3–In2S3 S-scheme in collaboration with 2D graphene oxide nanosheets. The material offers a well-defined nanosheet and nanoflake morphology for the effective contact with and catalysis of crystal violet (CV) dye as a model contaminant. Compared to Sn2S3–In2S3/GO, the pristine Sn2S3 and Sn2S3–In2S3 cause negligible degradation of CV using a visible-light source. This enhanced photocatalysis is supported by the peculiar properties of GO, such as its high surface area, electron-shuttling performance, and ability to prevent charge back-recombination. Under simulated conditions, more than 99% of CV was mineralized within 60 min of contact time. The photodegradation follows pseudo-first-order kinetics with a rate constant (Kt) = 0.02317 min−1. Furthermore, the photo mineralization of CV dye was thoroughly investigated using the GC-MS technique. More importantly, Sn2S3–In2S3/GO exhibits promising recyclability over multiple degradation cycles. [ABSTRACT FROM AUTHOR]

Recently, transparent and flexible surface-enhanced Raman scattering (SERS) substrates have received great interest for direct point-of-care detection of analytes on irregular nonplanar surfaces. In this study, we proposed a simple cost-effective strategy to develop a flexible SERS patch utilizing multibranched sharp spiked gold nanostars (GNS) decorated on a commercially available adhesive Scotch Tape for achieving ultra-high SERS sensitivity. The experimental SERS measurements were correlated with theoretical finite element modeling (FEM), which indicates that the GNS having a 2.5 nm branch tip diameter (GNS-4) exhibits the strongest SERS enhancement. Using rhodamine 6G (R6G) as a model analyte, the SERS performance of the flexible SERS patch exhibited a minimum detection limit of R6G as low as 1 pM. The enhancement factor of the SERS patch with GNS-4 was calculated as 6.2 × 108, which indicates that our flexible SERS substrate has the potential to achieve ultra-high sensitivity. The reproducibility was tested with 30 different spots showing a relative standard deviation (RSD) of SERS intensity of about 5.4%, indicating good reproducibility of the SERS platform. To illustrate the usefulness of the flexible SERS sensor patch, we investigated the detection of a carcinogenic compound crystal violet (CV) on fish scales, which is often used as an effective antifungal agent in the aquaculture industry. The results realized the trace detection of CV with the minimum detection limit as low as 1 pM. We believe that our transparent, and flexible SERS patch based on GNS-4 has potential as a versatile, low-cost platform for real-world SERS sensing applications on nonplanar surfaces. [ABSTRACT FROM AUTHOR]

In this paper, nanocomposite NiO/Cr2O3 has been synthesized by a simple chemical reduction method to study its photocatalytic activity under sunlight irradiation. Various advanced analytical techniques including powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), elemental mapping, Fourier transform infrared spectroscopy (FTIR), and UV-visible spectroscopy have been utilized to characterize the synthesized NiO/Cr2O3 nanocomposite. SEM images show the sheet-shaped morphology of NiO/Cr2O3 nanocomposite. These sheets have a rough surface with nano to micro size cracks. These cracks play important role in the enhancement of photocatalytic activity by increasing surface active sites for the adsorption of dye molecules on the surface of the photocatalyst. The organic dyes crystal violet (CV) and methylene blue (MB) have been chosen to study the photocatalytic behavior of NiO/Cr2O3 nanocomposite under sunlight irradiation. The photocatalytic efficiency of NiO/Cr2O3 nanocomposite has been obtained 88.47% and 93.63% against crystal violet and methylene blue respectively. The results of the photocatalytic kinetics exhibit that degradation rate constant value for crystal violet dye is higher as compared to methylene blue dye. Obtained kinetic results indicate that synthesized nanocomposite acts as an efficient photocatalyst for the degradation of both crystal violet dye and methylene blue dye. NiO/Cr2O3 nanocomposite also exhibited reusability and stability for photocatalytic degradation of both organic dyes. Photoelectrochemical measurements as photocurrent, electrochemical impedance spectroscopy (EIS), and Mott-Schottky plot were also performed for synthesized NiO/Cr2O3 nanocomposite. Consequently, this synthesized NiO/Cr2O3 nanocomposite can be utilized for environmental remediation of harmful dyes. [ABSTRACT FROM AUTHOR]

This paper reports a novel, low-cost, and facile approach to prepare a hybrid material consisting of zeolite, Fe3O4, and graphitic carbon nitride as a sorbent to remove methyl violet 6b (MV) from aqueous solutions. To improve the performance of the zeolite for the removal of MV, graphitic carbon nitride (with different C-N bonds and conjugated π region) was used. Also, to perform an easy and fast separation of sorbent from aqueous media, magnetic nanoparticles were incorporated into the sorbent. The prepared sorbent was characterized by different analytical techniques such as X-ray diffraction analysis, Fourier transform infrared, field emission scanning electron microscopy, and energy-dispersive X-ray analysis. The effects of four parameters of initial pH, initial concentration of MV, contact time, and the adsorbent amount on the removal process were investigated and optimized by the central composite design method. The removal efficiency of MV was modeled as a function of the experimental parameters. Affording to the proposed model, the values of 10 mg, 28 mg L−1, and 2 min were selected as optimum condition for adsorbent amount, initial concentration, and contact time, respectively. Under this condition, the optimal removal efficiency was 86% ± 2.8 which were close to the predicted value of the model (89%). Therefore, the model could fit and predict the data. The maximal adsorption capacity of sorbent derived from Langmuir's isotherm was 384.6 mg g−1. The applied composite can efficiently remove MV from various wastewater samples (paint, textile industries, pesticide production wastewater samples, and municipal wastewater). [ABSTRACT FROM AUTHOR]

Electrolysis technology is very effective in removing organic pollutants including dye wastewater and takes into account environmental friendliness. This paper deals with the electrochemical degradation of triphenylmethane dye crystal violet (DCV) from the aqueous solution using 304 stainless steel electrodes. The electrolytic cell device with a flotation column structure was set up and the electrolytic degradation process was studied. It could be found that the DCV removal efficiency and reaction rate constants were fitting the first‐order kinetic model. The process performance was analyzed in terms of degradation efficiency and energy consumption. Almost complete degradation (>98%) of 100 mg/L DCV was achieved after the 40 min reaction under the conditions of 300 mg/L NaCl dosage, nature pH (5–7), and 10 V applied voltage. Finally, the behaviours of degradation were studied. In the process of electrochemical degradation, the synergistic effects of electrode electrolysis, including indirect oxidation of electrolyte, hydroxyl radical, flocculation, and air flotation, removed the dye pollutants from the wastewater. The present study has proved the effectiveness and cleanness of electrochemical treatment for the triphenylmethane dye solution. [ABSTRACT FROM AUTHOR]

A new generation of clay-based nano pigments has been introduced, providing the advantage of both inorganic pigments and organic dyes. These nano pigments have been synthesized through a stepwise procedure where, initially, an organic dye is adsorbed onto the surface of the adsorbent, and then dye adsorbed adsorbent is used as pigment for further applications. The objective of the current paper was to examine the interaction of non-biodegradable toxic dyes, Crystal Violet (CV) and Indigo Carmine (IC), with clay minerals (montmorillonite (Mt), vermiculite (Vt), and clay bentonite (Bent)) and their organically modified forms (OMt, OBent, and OVt) and to develop a novel methodology for the synthesis of the value-added products and clay-based nano pigments without creating second generation waste materials. In our observation, the uptake of CV was more intense onto pristine Mt, Bent, and Vt, and the uptake of IC was more onto OMt, OBent, and OVt. CV was found to be in the interlayer region of Mt and Bent, as supported by XRD data. Zeta potential values confirmed the presence of CV on their surface. In contrast, in the case of Vt and organically modified forms, the dye was found on the surface, confirmed by XRD and zeta potential values. In the case of indigo carmine, the dye was found only on the surface of pristine Mt, Bent, Vt, and organo Mt, Bent, Vt. During the interaction of CV and IC with clay and organoclays, intense violet and blue-colored solid residues were obtained (also known as clay-based nano pigments). The nano pigments were used as colorants in a poly (methyl-methacrylate) (PMMA) polymer matrix to form transparent polymer films. [ABSTRACT FROM AUTHOR]

Pollution with organic dyes is one of the most typical environmental problems related to industrial wastewater. The removal of these dyes opens up new prospects for environmental remediation, but the design of sustainable and inexpensive systems for water purification is a fundamental challenge. This paper reports the synthesis of novel fortified hydrogels that can bind and remove organic dyes from aqueous solutions. These hydrophilic conetworks consist of chemically modified poly(ethylene glycol) (PEG-m) and multifunctional cellulose macromonomers ("cellu-mers"). Williamson etherification with 4-vinylbenzyl chloride (4-VBC) is used to modify PEGs of different molecular masses (1, 5, 6, and 10 kDa) and cellobiose, Sigmacell, or Technocell™ T-90 cellulose (products derived from natural renewable resources) with polymerizable/crosslinkable moieties. The networks are formed with good (75%) to excellent (96%) yields. They show good swelling and have good mechanical properties according to rheological tests. Scanning electron microscopy (SEM) reveals that cellulose fibers are visibly embedded into the inner hydrogel structure. The ability to bind and remove organic dyes, such as bromophenol blue (BPB), methylene blue (MB), and crystal violet (CV), from aqueous solutions hints at the potential of the new cellulosic hydrogels for environmental cleanup and clean water safeguarding. [ABSTRACT FROM AUTHOR]

In this paper, a hydrothermal method has been used to synthesize Ni-doped CdS (Ni–CdS) flowers-like with high-surface area by using simple materials with different Ni concentrations (0%, 1%, 2%, 3%, 4%, and 5%). Structural, morphological, and optical characteristics were described by X-ray diffraction (XRD), FE-SEM, AFM, UV-Visible, and photoluminescence (PL) spectroscopy. The pattern of XRD shows that all films have the preferential orientation at H (002)/C (111) with hexagonal and cubic phases, with crystallite sizes ranging from 10.7 to 7.3 nm. The transmittance and energy gap at different doping concentrations were measured and calculated. Results show an increase in Ni doping concentration decreased the energy gap. FE-SEM images proved the nano-flaked and flower-like nanostructures. The performance of the undoped and doped CdS films was examined for the photocatalytic of organic dyes (methyl blue and methyl violet). In addition, the degradation of dyes in an aqueous solution under xenon light at room temperature of the CdS and Ni: CdS films were evaluated. [ABSTRACT FROM AUTHOR]

In this paper, AgIn5S8/MoS2 was prepared simply by a one-pot hydrothermal method and employed in the selective removal of methylene blue (MB) from an aqueous solution. Synthesis conditions of the AgIn5S8/MoS2 composite were optimized by surface area. The morphology and structure of the AgIn5S8/MoS2 composite were also characterized by Fourier transform infrared spectroscopy, x-ray diffraction, nitrogen adsorption-desorption, x-ray photoelectron spectroscopy, and scanning electron microscope. It proved that petal-like nanostructures of MoS2 were generated on flower-like AgIn5S8 and the surface area of the AgIn5S8/MoS2 composite (170.1 m2 g−1) is much larger than both pure MoS2 (8.4 m2 g−1) and pure AgIn5S8 (60.9 m2 g−1). Factors of pH and contact time affecting AgIn5S8/MoS2 adsorption of MB were studied in detail. The adsorptive equilibrium times of AgIn5S8/MoS2 for different concentration MB are all very fast within 60 min. The adsorptive kinetics, isotherms, and thermodynamics reveal that the adsorptive progress is well-described by the pseudo-second-order kinetic model and Langmuir isotherm equations and spontaneous and endothermic (∆G° < 0, ∆H° > 0, ∆S° > 0), respectively. The results imply that the AgIn5S8/MoS2 composite with the maximum adsorptive capacity of 90.0 mg g−1 at 25 °C could be used as a potential adsorbent for MB in acidic wastewater as well as printing and dyeing wastewater. Besides, it can also specifically adsorb methyl blue but not methyl violet under alkaline conditions. [ABSTRACT FROM AUTHOR]

Highly efficient and low-cost materials for the degradation of organic dyes in wastewater remain the focus of environmental protection and water pollution control, in which, nanozymes have been at the forefront for the development of a new platform and aroused more and more attention. In this work, a nanoceria@shaddock peel-derived nanocomposite (Ce@CSP) with excellent peroxidase-like performance in methyl violet (MV) degradation as well as ascorbic acid (AA) detection was synthesized by a simple one step in situ pyrolysis of cerium ammonium nitrate (Ce(NH4)2(NO3)6) and pretreated shaddock peel. By means of the cooperative-reinforcing peroxidase-like activity of the porous carbon material originating from shaddock peel (CSP) and the loaded CeO2 nanoparticle, the obtained nanozyme Ce@CSP displayed a superior catalytic ability in the catalyzed oxidation of the chromogenic substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2. Specifically, a synergetic absorbent property was also demonstrated by the porous carbon material, bringing the target molecules in close proximity to the nanozyme catalyst and therefore enabling effective decoloration of MV and colorimetric detection of AA with a linear range of 1.6–17.3 μM and a detection limit of 1.07 μM. The current work has realized effective decoloration of MV in real water samples and provided a wide range of potential applications of low-cost and eco-friendly materials in organic dye treatment. [ABSTRACT FROM AUTHOR]

Herein, magnesium–aluminum layered double hydroxides (Mg–Al-LDH) were synthesized by an environmentally friendly and economically promising hydrothermal technique for the adsorption of the dye reactive green 5 (RG5). To further enhance the RG5 dye adsorption capability of Mg–Al-LDH, their composites were designed by using low-cost Mangifera indica stone biomass (MISB). From their physiochemical properties evaluated by scanning electron microscopy and Fourier transform infrared spectroscopy, they were found to display an irregular morphology along with the existence of various functional groups (including OH, C＝O, and C–H) on surfaces, enabling prepared biosorbents to be excellent candidates for adsorption. Batch adsorption trials were conducted to determine the comparative RG5 dye adsorption efficiencies of MISB, Mg–Al-LDH and the Mg–Al-LDH@MISB composite in an aqueous medium. The highest RG5 dye adsorption capacities recorded under optimized conditions (contact time: 90 min, pH: 3, adsorbent dosage: 0.05 g, initial RG5 dye concentration: 80 mg L−1 and temperature: 30 °C) for MISB, Mg–Al-LDH and the Mg–Al-LDH@MISB composite were 55.9 mg g−1, 68.4 mg g−1 and 73.5 mg g−1, respectively. The kinetic and isothermal study showed the best fit of the pseudo 2nd order and Freundlich models. Thermodynamic parameters illustrated the spontaneity of the process. In addition, the adsorbents as designed also possessed regeneration capability as evidenced by their RG5 dye desorption potential. Therefore, this research opens up new doors for the development of environmentally friendly Mg–Al-LDH by developing composites with economically feasible biomass for industrial wastewater treatment. [ABSTRACT FROM AUTHOR]

Water released by industries that generate coloured pollutants must be treated to safeguard the environment and ensure that the treated water is non-toxic. In this study, we demonstrate the utility of glycine-derived designer micelles, N-lauroyl-N-(pyridin-2-ylmethyl)glycine (PyN12G), as a capping agent to prepare black bismuth oxide nanoparticles (Bi2O3 NPs). The obtained Bi2O3 NPs were confirmed by X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy. Transmission electron microscopy demonstrated that the Bi2O3 NPs are crystalline, with a quasi-spherical morphology and an average size of 42.3 nm, which are further corroborated by powder X-ray diffraction studies to be monoclinic. Fourier transform infrared spectra revealed that the surface of Bi2O3 NPs was stabilized by PyN12G and that the –COOH group of the micelles was involved in surface functionalization. The application of Bi2O3 NPs in environmental remediation was demonstrated by degrading a toxic dye, Congo red (CR). Bi2O3 NPs catalyze sodium borohydride-mediated CR degradation with an efficiency of 88.8% in 15 minutes and a rate constant of 1.92 × 10−3 s−1. Besides CR, Bi2O3 NPs catalyzed the degradation of methylene blue, bromophenol blue, Coomassie blue, crystal violet, and rhodamine B with efficiencies of 95%, 92%, 95%, 90%, and 86%, respectively. Gas chromatography-mass spectrometry analysis reveals that CR is degraded into smaller molecules. The disclosed dye degradation process eliminates the hazardous feature of the dye, which was proven by the seed germination assay. Furthermore, toxicology experiments revealed that Bi2O3 NPs do not affect bacterial growth or seed germination, proving that the NPs are non-toxic and safe to use as a chemocatalyst to eliminate toxic dyes without affecting the environment. [ABSTRACT FROM AUTHOR]

In this paper, we have synthesised SBA-S4, as a mesoporous silica-based sorbent, via template method by functionalization of SBA-15 using the tetra-sulphide group. The prepared structure was applied to remove Crystal Violet (CV) and Methyl Green (MG) dyes with 100% efficiency. The obtained adsorbent, after and before the modification, was characterised by several techniques to explore textural properties, functional groups, and morphology. Design-Expert was applied to find the optimal values of adsorbent dosage, the solution pH, and the concentration of each dye as experimental variables. It was found that the isotherm model and kinetic rate order fitted Langmuir and pseudo-second-order, respectively. The maximum adsorption capacity of the studied sorbent was 67.6 and 39.4 mg g−1 for CV and MG, respectively. The results also showed that SBA-S4 had high efficiency for eliminating the studied analytes in tap water, well water, and river water as real matrix samples. Reusability and regeneration studies indicated that the studied sorbent can be applied more than 5 cycles with a negligible loss of efficiency. [ABSTRACT FROM AUTHOR]

In recent years, the research of phenylethynylcopper (PhC2Cu) in photocatalysis has attracted immense attention. However, its synthesis requires two steps extending over 9 days. In this paper, the successful preparation of PhC2Cu nanowires is reported using a highly rapid and facile one-step method directly using copper acetate and phenylacetylene as raw materials and ascorbic acid as reducing agent. The kinetic studies indicated that the synthetic reaction follows a pseudo-second-order equation through electrical conductivity. Comparative studies of the crystal structures, morphologies, and optical properties of PhC2Cu prepared by the traditional two-step and the current one-step methods were conducted using XRD, SEM, UV–Vis Drs, FT-IR, Raman spectra, and photocurrent. Meanwhile, the PhC2Cu nanowires exhibited excellent photocatalytic activity to degrade methyl violet (MV) and glyphosate. This facile and rapid method dramatically improves the preparation efficiency of PhC2Cu, and the obtained PhC2Cu also shows higher photocatalytic activity. This remarkable progress enables the possibility of large-scale and efficient preparation of PhC2Cu with high photocatalytic activity, indicating their excellent application prospect in photocatalysis. [ABSTRACT FROM AUTHOR]

Improving the detection limit of surface-enhanced Raman scattering (SERS) is a significant issue for the design and application of plasmon substrate. It always suffers from the weak affinity of probe molecules on the nanoscale surface, uncontrollable aggregation behaviors of nanoparticles, and strong fluorescence of the detected substance. In this paper, AgNPs/SiO2 substrate is prepared by a rapid thermal annealing method with a mean size of 87.9 ± 30.7 nm. A layer of 5–30 nm PVA (polyvinyl alcohol) film is used as the stabilizer of AgNPs. With PVA coating, AgNPs can improve the detection limit of gentian violet by three magnitudes, compared with the one on undecorated AgNPs which is just 10−5 mol/L. In the sensitive detection using coated AgNPs/SiO2 substrate, PVA possibly plays three significant roles, affinity increaser between gentian violet and silver nanoparticles, fluorescence inhibiter of gentian violet, and stabilizer of Ag nanoparticles. The results provide a modification method for improving SERS sensitivity of plasmon substrate, which uses convenient and low-cost rapid thermal annealing as the patterning method and PVA as the coater, an advantageous technology for plasmon substrate application into trace detection. [ABSTRACT FROM AUTHOR]

A novel natural macromolecule stabilizer, tea polyphenol, was developed based on the scavenging effect of nitroxide radical to enhance the thermal stability of nitrocellulose. The structural of tea polyphenols was confirmed by infrared spectroscopy, and their good thermal stability of tea polyphenols in nitrocellulose was confirmed by methyl violet paper test and vacuum stability test. The iso-thermogravimetric test showed that tea polyphenols could prolong the safe storage life of nitrocellulose. The inhibition of tea polyphenols on the autocatalytic thermal decomposition of nitrocellulose in the early stage of nitrocellulose thermal decomposition was confirmed by SEM images at different stages of nitrocellulose thermal decomposition. The thermal interaction between tea polyphenols and nitrocellulose was further analyzed by non-isothermal thermal analysis. Experiments confirmed that tea polyphenols can enhance the thermal stability of nitrocellulose. Their addition increased the T0 of nitrocellulose by 2.0–9.4 ℃, the Tbp0 by 1.4–9.6 ℃, and the activation energy of nitrocellulose by 5.38–9.77 kJ·mol–1. [ABSTRACT FROM AUTHOR]

Adsorption is one of the effective methods of treating dye wastewater. However, the selection of suitable adsorbent materials is the key to treating dye wastewater. In this paper, GO−ATP was prepared by an intercalation method by inserting graphene oxide (GO) into the interlayer of alabaster attapulgite (ATP), and GO−ATP@CS−PVA aerogel was prepared by co−blending−crosslinking with chitosan (CS) and polyvinyl alcohol (PVA) for the adsorption and removal of crystalline violet dye from the solution. The physicochemical properties of the materials are characterized by various methods. The results showed that the layer spacing of the GO−ATP increased from 1.063 nm to 1.185 nm for the ATP, and the specific surface area was 187.65 m2·g−1, which was 45.7% greater than that of the ATP. The FTIR results further confirmed the success of the GO−ATP intercalation modification. The thermogravimetric analysis (TGA) results show that the aerogel has good thermal stability properties. The results of static adsorption experiments show that at 302 K and pH 9.0, the adsorption capacity of the GO−ATP@CS−PVA aerogel is 136.06 mg·g−1. The mass of the aerogel after adsorption−solution equilibrium is 11.4 times that of the initial mass, with excellent adsorption capacity. The quasi−secondary kinetic, Freundlich, and Temkin isotherm models can better describe the adsorption process of the aerogel. The biobased composite aerogel GO−ATP@CS−PVA has good swelling properties, a large specific surface area, easy collection and a low preparation cost. The good network structure gives it unique resilience. The incorporation of clay as a nano−filler can also improve the mechanical properties of the composite aerogel. [ABSTRACT FROM AUTHOR]

At present, the use of efficient and cost-effective methods to construct plasmonic surface-enhanced Raman scattering (SERS) substrates of high sensitivity, uniformity and reproducibility is still crucial to satisfy the practical application of SERS technology. In this paper, a localized surface plasmonic resonance (LSPR) tunable flexible Ag@PDMS substrate was successfully constructed by the low-cost bio-template-stripping method and magnetron sputtering technology. The theory proves that the local electromagnetic field enhancement and "hot spot" distribution is adjustable by modifying the size of the optical cavity unit in the periodicity nanocavity array structure. Experimentally, using rhodamine 6G (R6G) as the target analyte, the SERS performance of optimal Ag@PDMS substrate (Ag film thickness for 315 nm) was researched in detail, which the minimum detection limit was 10−11 M and the enhancement factor was calculated as 8.03 × 108, indicating its high sensitivity. The relative standard deviation (RSD) was calculated as 10.38%, showing that the prepared substrate had excellent electromagnetic field enhancement uniformity. At last, the trace detection of Crystal violet (CV, LOD = 10−9 M) and the simultaneous detection of three common dyes (R6G, CV and Methylene blue (MB) mixture) were also realized. This result suggests that the SERS substrate has a good application prospect in the quantitative and qualitative detection of dye molecules. [ABSTRACT FROM AUTHOR]

In recent years, surface-enhanced Raman scattering (SERS) technique based on localized electromagnetic field enhancement on noble metal surfaces has received extensive attention in the field of trace molecule sensing and detection. However, in the process of practical application, the current SERS detection performance is still unable to achieve high detection sensitivity and high repeatability at the same time. In this paper, an efficient and controllable preparation method of Ag–Au composite cascade hollow nanoarray SERS substrates were provided based on nanoimprinting, conformal transfer and electrodeposition techniques. Crystal Violet (CV) was used as the probe molecule, and a low relative standard deviation of 6.65% of SERS intensity was obtained, and the detection concentration could be as low as 10 − 9 M, which can meet the needs of practical applications. The structure has multi-scale cascade characteristics, and significantly broadens the electromagnetic field enhancement characteristics of traditional single-scale configuration nanostructures on the premise of ensuring the uniformity of SERS detection. Such substrates can provide more abundant molecular adsorption sites, which is conducive to improving SERS detection sensitivity and stability. This method is universal, simple and with controllable and repeatable preparation process, which has good application potential in the construction of large-area uniform cascaded nanoarray structure SERS substrates. An efficient and controllable preparation method of Ag–Au composite cascade hollow nanoarray SERS substrates was provided based on nanoimprinting, conformal transfer and electrodeposition techniques. [ABSTRACT FROM AUTHOR]