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Abstract\nIn this research, a nanocomposite called AAZG-NCPs was synthesized and analyzed. The nanocomposite showed a surface area of 10.57 ± 0.31 m2/g, a pore size of 0.07299 ± 0.002 cm3/g, and ferromagnetic properties with a magnetization of 3.9 ± 0.12 emu/g. Its band gap energy was found to be 2 ± 0.1 eV. The surface charge of the synthesized AAZG-NCPs was determined to be −29 ± 0.6 mV. A pHZPC value of 6.6 ± 0.04 was calculated using the salt addition method. The photocatalytic activity and optimization of the Crystal violet (CV) photodegradation process using synthesized AAZG-NCPs was investigated using Box Behnken design and Design Expert software. A polynomial equation was obtained for the experimental data, with a calculated R2, Adj-R2, and Pred-R2 values in the model were 0.998, 0.9977, and 0.9947 respectively, indicating a strong proportion between the model fitting and experimental data. The photocatalytic degradation of CV achieved a maximum efficiency of 98.7 ± 1% under optimum conditions at pH = 9, CV concentration of 5.7 mg/L, AAZG-NCPs amount of 0.075 g/L, and temperature of 40 °C under visible light. The kinetics study indicated a pseudo-first-order kinetics model with a rate constant of 0.0441 ± 0.002 min−1.A novel magnetic photocatalyst Ag2CrO4/Ag/ZnFe2O4/g-C3N4 was used for Crystal Violet dye degradation under Visible light.The degradation of Crystal Violet dye (5.7 mg/L) is quasi-total after 90 minute.The Box-Behnken design was used for optimization of the process.Crystal Violet dye degradation obeys a pseudo-first-order kinetics. [ABSTRACT FROM AUTHOR]

Utilising the solution combustion technique, nanocrystalline photocatalysts that included both pristine TiO2 and doped TiO2 with various La (III) dopant percentages (1, 3, 5, and 7 mol%) were created. Different methods, including thermal analysis, high resolution-transmission electron microscopy (HR-TEM), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT-IR), and field-emission scanning electron microscopy (FE-SEM), were used to investigate the prepared nanostructures. The XRD results indicated the anatase form and the crystalline nature of the products (pristine and doped TiO2) in the size range of a crystallite (5–16.5) nm. The photocatalytic assessment of the prepared nano-photocatalysts was carried out by crystal violet (CV) decolourisation under ultraviolet (UV) light. The findings revealed that 3% La-TiO2 showed the highest degradation efficiency (95.98%) in 70 min with a pseudo-first-rate constant of k = 4.73 × 10−2 min−1, compared to pristine TiO2 and the other TiO2 nanostructures with various La (III) dopant ratios. [ABSTRACT FROM AUTHOR]

This research demonstrates the ability of cubic Ia3d aluminosilica (CAS) adsorbent prepared using a simple and repeatable one-pot synthesis technique to remove the cationic dye, such as Gentian violet (GV) from aqueous solutions. The prepared CAS adsorbent nanoarchitectonics appeared with 573 m2 g−1 as a BET surface area. The adsorption behaviour of GV on CAS adsorbent was investigated using the thermodynamics, kinetics, and isotherm models. According to the results, the CAS adsorbent indicated a high ability to absorb GV from an aqueous solution, and their kinetic behaviour follows a pseudo-second-order kinetic. In addition, the equilibrium study revealed that the GV adsorption by the CAS adsorbent followed the Langmuir model. Additionally, the outcomes obtained revealed adsorption of GV onto CAS adsorbent was dominated by electrostatic attraction forces, hydrogen bonding, ion-exchange, and pore filling, The maximum adsorption efficiency of GV onto CAS adsorbent was instituted to be 1.36 mmol g−1 (i.e. 554.85 mg g−1). The enthalpy (ΔHo), entropy (ΔGo), and Gibbs free energy (ΔSo) parameters revealed that the extraction of GV dye using CAS adsorbent was endothermic and spontaneous. The synthesised CAS adsorbent shows significant recyclability and characteristics of re-generability up to five adsorption-desorption cycles. As a proof of concept, the performance of the prepared adsorbent was evaluated for laboratory-scale purification of wastewater samples. [ABSTRACT FROM AUTHOR]

Synthetic dyes are prevalent in aquatic environments, they have high toxicities, are non-degradable, and accumulate in the water. The removal of Crystal violet (CV) is carried out using batch experiments on the Salsola Tetragona (ST) plant as a novel adsorbent. The prepared adsorbent was analyzed by various methods (MEB, EDX, IRTF and PZC), to support its applicability as adsorbent. The adsorption study of CV is performed by optimizing the parameters affecting the adsorption process. The adsorption kinetics study is represented by pseudo-second-order (R2 = 0.999) and the adsorption process is limited by external mass transport. In addition, the isotherm results demonstrate that the Langmuir model interprets better the adsorption isotherm. The thermodynamic parameters suggest that the adsorption phenomena are spontaneous and exothermic. Furthermore, the adsorption reactions involved are of physisorption type, which facilitates the desorption of pollutants from the surface of the adsorbent. The results show that ST adsorbent effectively removes CV in an aqueous solution, which is demonstrated by the maximum amount adsorption of 246.7 mg.g−1 at optimum adsorption conditions: pH = 6, adsorbent dose of 0.5 g.L−1, initial CV concentration of 10 mg.L−1, and adsorption time of 30 min at 298 K. Finally, these results can be considered as a useful reference for wastewater treatment using ST. The novelty of our work, entitled "Salsola Tetragona as a New Low-Cost Adsorbent for Water Treatment: Highly Effective Adsorption of Crystal Violet", lies in the utilization of a new biomass abundant in the southwestern region of Morocco. This plant as a novel material is used in its raw state as an adsorbent for removing a cationic dye. According to the literature, this material has not been previously employed in water treatment. Hence, to fill the gap in the literature, we examined its in-batch adsorption to remove crystal violet from the aqueous solution. The results show a high adsorption capacity compared to other natural biomass. [ABSTRACT FROM AUTHOR]

The present study investigated crystal violet removal by modifying the chestnut shell with a chemical activation method. For this purpose, H2SO4 and NaOH pretreatments were applied to the chestnut shell and the pretreatment method that gave the best performance under the same conditions was determined. The best adsorption efficiency was achieved with the NaOH pretreatment (99.06%) and the crystal violet adsorption reached equilibrium within 60 min. After selecting the best chemical activation method, the modified chestnut shell was characterized before and after adsorption (FTIR and SEM). Furthermore, the effects of parameters such as pH, initial crystal violet concentration, adsorbent dosage, temperature, and contact time were observed. Moreover, isotherm, kinetics and thermodynamics of the adsorption process were researched in detail. The best results were obtained with the Langmuir isotherm model (R2=0.99) and the pseudo-second-order kinetic model (R2=0.99). Thermodynamic parameters showed that the adsorption process is spontaneous, endothermic and feasible. [ABSTRACT FROM AUTHOR]

Co-carbonization of waste biomass is of great interest to reduce production costs and increase carbon yields. In this study, it was investigated to produce cost-effective and high carbon yield activated carbons by carbonizing lemna minor (LM) and hazelnut shell (HS) wastes together. In this context, LM and HS were co-carbonized at 800°C, 100 mL/min of N2 for 90 min, and their carbonization yields, adsorption capacities, physical and chemical properties were determined. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), ultimate and proximate analysis were performed. According to XRD analysis, HS is amorphous, LM is semi-crystalline, but the crystalline structure increased after co-carbonization. Based on the FTIR analysis LM, HS, and cLM/HS contain various functional groups, including O-H, C-H, and C-O. The adsorption capacity and CV removal, obtained by co-carbonized LM and HS (cLM/HS), are 87.95 mg/g and 88%, respectively. Its specific surface area is 745 m2/g. This study showed that the cLM/HS is a cost-effective adsorbent for the removal of crystal violet dye. [ABSTRACT FROM AUTHOR]

In this investigation, microwave irradiation assisted by ZnCl2 was used to transform pineapple crown (PN) waste into mesoporous activated carbon (PNAC). Complementary techniques were employed to examine the physicochemical characteristics of PNAC, including BET, FTIR, SEM-EDX, XRD, and pH at the point-of-zero-charge (pHpzc). PNAC is mesoporous adsorbent with a surface area of 1070 m2/g. The statistical optimization for the adsorption process of two model cationic dyes (methylene blue: MB and, crystal violet: CV) was conducted using the response surface methodology-Box-Behnken design (RSM-BBD). The parameters include solution pH (4–10), contact time (2–12) min, and PNAC dosage (0.02–0.1 g/100 mL). The Freundlich and Langmuir models adequately described the dye adsorption isotherm results for the MB and CV systems, whereas the pseudo-second order kinetic model accounted for the time dependent adsorption results. The maximum adsorption capacity (qmax) for PNAC with the two tested dyes are listed: 263.9 mg/g for CV and 274.8 mg/g for MB. The unique adsorption mechanism of MB and CV dyes by PNAC implicates multiple contributions to the adsorption process such as pore filling, electrostatic forces, H-bonding, and π-π interactions. This study illustrates the possibility of transforming PN into activated carbon (PNAC) with the potential to remove two cationic dyes from aqueous media. The novelty of this research work stems from the conversion of pineapple (Ananas comosus) crown wastes with no monetary value into an efficient activated carbon adsorbent with relatively high surface area. Furthermore, a fast and convenient microwave assisted ZnCl2 activation method was applied for producing the activated carbon (AC). The effectiveness of the produced AC was tested for the removal of two different cationic dyes: crystal violet (CV) and methylene blue (MB). A statistical optimization that employs a response surface methodology with the Box-Behnken design was employed to optimize the adsorption variables for the optimal dye removal. Moreover, the dye adsorption kinetics and thermodynamics, equilibrium isotherms, and the details of the adsorption process were reported herein. [ABSTRACT FROM AUTHOR]

The objective of this study is to develop a low-cost biosorbent using residual seeds of the Citrullus lanatus fruit for the removal of cationic dyes. Physicochemical parameters such as pH, adsorbent mass, contact time, and temperature were evaluated for their effects on dye removal. The biosorbent is composed of lignin and cellulose, exhibiting a highly heterogeneous surface with randomly distributed cavities and bulges. The adsorption of both dyes was most effective at natural pH with a dosage of 0.8 g L−1. Equilibrium was reached within 120 min, regardless of concentration, indicating rapid kinetics. The Elovich model and pseudo-second-order kinetics were observed for crystal violet and basic fuchsin dye, respectively. The Langmuir model fitted well with the equilibrium data of both dyes. However, the increased temperature had a negative impact on dye adsorption. The biosorbent also demonstrated satisfactory performance (R = 43%) against a synthetic mixture of dyes and inorganic salts, with a small mass transfer zone. The adsorption capacities for crystal violet and basic fuchsin dye were 48.13 mg g−1 and 44.26 mg g−1, respectively. Thermodynamic studies confirmed an exothermic nature of adsorption. Overall, this low-cost biosorbent showed potential for the removal of dyes from aqueous solutions. In this work, a novel biosorbent was developed using residual Citrullus lanatus fruit seeds that can efficiently remove cationic dyes from aqueous solutions. The biosorbent's composition includes lignin and cellulose, and its surface structure is highly heterogeneous, consisting of randomly distributed cavities and bulges. The biosorbent demonstrated a rapid and efficient adsorption capacity for both crystal violet and basic fuchsin, regardless of dye concentration. Moreover, the biosorbent was successfully employed in the treatment of a synthetic mixture containing several dyes and inorganic salts. Finally, the application of the biosorbent in continuous adsorption showed a low zone of mass transfer and high breakthrough time, indicating it to be an excellent material for fixed-bed operation. Overall, this study provides a low-cost and efficient alternative for the removal of dyes from aqueous solutions, with promising practical applications. Citrullus lanatus seed powder was produced and characterized. Crystal Violet (CV) and Basic Fuchsin (BF) contaminants were successfully removed by the powder. Low mass-transfer zone length and good adsorption capacities were obtained in a continuous system. A good performance was observed against a synthetic mixture. [ABSTRACT FROM AUTHOR]

The present investigation demonstrates the augmented dye scavenging from wastewater using alkali-mutated acacia (Acacia auriculiformis) leaves powder. The material was synthesized by mild chemical activation by using 0.1 M sodium hydroxide as an activator under room temperature stirring for 3h and isolated as a dark brown powder. The material was characterized using FTIR, FESEM, XRD, and pHzpc; and tested successfully with crystal violet and methylene blue. While FTIR confirms the presence of polyphenolic and polysaccharide moieties, FESEM reveals unprecedented circular hollow pipe-like channels decorated in a highly ordered fashion, facing pores for optimum dye uptake. The adsorption is tunable with working pH, and the maximum adsorption capacities are 67.25 and 78.55 mg g−1 for CV and MB. Both adsorption process follows Langmuir isotherm (R2 = 0.994) and pseudo-2nd-order kinetics (R2 = 0.999). Thermodynamic analysis verifies a spontaneous process with an endothermic interaction beside an elevated degree of randomness. About 80% of the spent material could be regenerated using 1:1 methanol/water. Analysis of industrial effluent suggests 37% removal per cycle, with an operating ceiling of 95%. To wind up, due to huge availability, porous nature, and superior adsorption capacity over other phytosorbents, NaOH-activated acacia leaves could be considered as techno-economic and potential scavengers for sustainable water treatment. Lignocellulosic waste plant litters have enormous potential for biosorption of heavy metals and dyes for their economic viability and environment-friendly nature. The present investigation highlights the promising cationic dye scavenging ability of alkali-treated waste acacia (A. auriculiformis) leaves from simulated and industrial wastewater. With adsorption capacities of 67.25 and 78.55 mg g−1 for crystal violet and methylene blue respectively, the protocol shows promise in colored water treatment. Easy preparation, classy removal efficiency, and recyclability offer the key advantage with a techno-economic impact. [ABSTRACT FROM AUTHOR]

In this work, novel mixtures based on silicon and tin materials were synthesised via reaction of 2.407, 5.247, 7.195, or 9.59 g of tin chloride dihydrate with 6 g of sodium metasilicate pentahydrate. The samples, which were synthesised using 2.407, 5.247, 7.195, and 9.59 g, are abbreviated as T1, T2, T3, and T4, respectively. XRD confirmed that these mixtures consist of amorphous Sn/Si, sodium tin silicate, tin oxide, and sodium silicate. The average crystallite size of T1, T2, T3, and T4 samples is 5.23, 8.13, 12.26, 15.72 nm, respectively. The synthesised mixtures were used as adsorbents for the removal of methylene blue and crystal violet dyes from aqueous media. 15 min, pH 6, and 298 Kelvin are regarded as the optimum conditions for the removal of studied dyes using T1, T2, T3, and T4 samples. The adsorption process of crystal violet or methylene blue dyes was fitted well with the Langmuir equilibrium isotherm and pseudo-second-order kinetic model. The thermodynamic parameters confirmed that the removal of crystal violet and methylene blue dyes is chemical, spontaneous, and exothermic. The maximum adsorption capacity of T1, T2, T3, and T4 samples towards crystal violet dye is 34.81, 36.83, 29.46, and 11.98 mg/g, respectively. Also, the maximum adsorption capacity of T1, T2, T3, and T4 samples towards methylene blue dye is 30.13, 29.33, 17.09, and 13.43 mg/g, respectively. HCl: butanol (1:3) can efficiently desorb the dyes for three cycles of adsorption/desorption. Hence, the adsorbents can be used successfully several times for the removal of crystal violet and methylene blue dyes. [ABSTRACT FROM AUTHOR]

In this study, the leaves of juglans regia chemically treated with acetic acid and L-arginine were used as adsorbents for removal of crystal violet dye from aqueous solution. The adsorbents were characterised using powder x-ray diffraction, Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller techniques. The adsorption isotherm, kinetics and thermodynamic parameters were examined for adsorption of dye on various adsorbents. The effect of initial dye concentration on adsorption capacity was studied and maximum adsorption capacity of adsorbents as per Langmuir linear fit was found for (JRACD: 263.85 mg g−1, JRACCHR: 273.97 mg g−1 and JRLRG: 290.70 mg g−1) at an initial dye concentration of 300 ppm, pH of dye solution 8, dosage of adsorbent 0.3 g, contact time of 70 minutes and at temperature of 303.15 K. It was observed that Freundlich isotherm fitted well for adsorption of dye on all the adsorbents compared to Langmuir isotherm. The kinetics of adsorption was found to follow the linear pseudo-second-order rate equation (R2 ≥ 0.9967). The Gibbs free energy was spontaneous in nature for the three adsorbents. The response surface methodology was also applied for all the adsorbents and optimisation of initial dye concentration (100, 200, 300) ppm, dosage of adsorbent (0.1, 0.3, 0.5) g and pH of dye solution (2, 5, 8) led to the development of quadratic models. The maximum adsorption capacity as per response surface model was found as 260.12 mg g−1 for JRLRG under optimum conditions. The significance of these models was also characterised by analysis of variance test. Additionally, density functional theory was used to support the experimental analysis and using Fukui function analysis the site for adsorption has been proposed. [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]

In this study, a new nano mesoporous MCM-41@SiO2-NH-pydc was successfully synthesised and was used as a new and low-cost adsorbent for the simultaneous influential clean-up, preconcentration and determination of crystal violet (CV) and auramine O (AO) dyes. The as-synthesised sorbent was characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX), thermogravimetric (TGA) and derivative thermogravimetric (DTG) and Brunauer–Emmett–Teller (BET) techniques. The extraction performance was evaluated by dispersive solid phase micro extraction (DSPME) of CV and AO from real samples. The analysis was carried out by UV-Vis spectrophotometric. The analytical results confirmed that theMCM-41@SiO2-NH-pyd could be an appropriate candidate as asorbent forDSPME. The maximum recoveries (95.95% and 92.95% for CV and AO, respectively) was obtained at 0.015 g MCM-41@SiO2-NH-pydc sorbent, pH = 8.0, 500 μL DMF as eluent solvent, 20 and 10 min extraction and centrifuge time, respectively, and 50 second desorption time. After the optimum conditions, the limit of detection (LOD), quantification (LOQ) and linear range were obtained, 0.0010, 0.0033 and 0.008–0.6 mg L−1 for CV and 0.0056, 0.0187 and 0.03–1.5 mg L−1for AO, respectively. The relative standard deviations (RSD) for five analyses were 4.2% for CV and 4.6% for AO. In comprising with the previous reported methods, the developed method provided a relatively in expensive, time-saving and environmentally friendly advantages. The developed analytical method can be applied for the determination of CV and AO with sufficient sensitivity as well as acceptable reproducibility. [ABSTRACT FROM AUTHOR]

Plant parts have unfathomable potential in the synthesis of nanoparticles. The current study was designed for the photosynthesis of silver nanoparticles (NC-AgNPs) using bark extract of N. cadamba. Different analytical methods were used to characterize the synthesized nanoparticles. HR-TEM analysis identifies the formation of multi-shaped NC-AgNPs like spherical, quasi-spherical, rod-shaped, trigonal, square, pentagonal, and hexagonal with a size range of 18-91 nm. The crystallize size of NC-AgNPs was found to be 27.6 nm. The catalytic effectiveness of NC-AgNPs in degrading Crystal violet (CV) dye is remarkable. Important parameters such as the effect of catalyst dose and pH were investigated. Dose-dependentantioxidant activity of NC-AgNPs was determined by using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay. Low-cost synthesis and eco-friendly reagents were the salient features that made NC-AgNPs more attractive toward catalytic and antioxidant activities. N. cadamba bark was used the first time as a green source for the synthesis of silver nanoparticles. The synthesis of different shapes of nanoparticles in one-step synthesis. The study of NC-AgNPs for their catalytic and antioxidant activities is reported for the first time. [ABSTRACT FROM AUTHOR]

Aim of this research paper was to investigate the potential of fish scales as an adsorbent for crystal violet dye exclusion from wastewater and to optimize various adsorption parameters for maximum adsorption of dye. Parameters studied were solution pH, adsorbent dose, contact time, dye concentration, and temperature. Results showed maximum percentage degradation, i.e., 90% under optimized conditions such as pH 12 solution, 0.4 g adsorbent dose, with 40 min of exposure time and 40 ppm of dye concentration at 10 °C solution temperature. Adsorbent was characterized using FTIR, and SEM techniques to explore the functionality and to study morphology of adsorbent, respectively. Results confirmed that carboxyl, amino, phosphate, and sulfonate groups and heterogeneous adsorbent surface was accountable for crystal violet dye adsorption on fish scales. pH pzc of the fish scale was 8. Adsorption isotherms such as Langmuir, Freundlich, and D-R isotherm models were also investigated. Contact time data was applied to various kinetic models, i.e., pseudo-first order, and pseudo-second order kinetic models. Thermodynamic study was also investigated. Results confirmed that experimental data fitted well to Freundlich isotherm model ( R 2 = 0.9983) and pseudo second order kinetic model ( R 2 = 0.9970) as ARE error analysis values of these models were 1.191692 E + 06 and −160.66, respectively (lower than that of other models. Computed ΔG and ΔH values confirmed adsorption process to be spontaneous and of endothermic kind. Applicability of established procedure with tap water was 78% and regeneration percentage was 72% which showed the effectiveness of fish scales powder for removal of crystal violet dye from wastewater. [ABSTRACT FROM AUTHOR]

Fallen bamboo leaves (Bambusa bambos), hereinafter BL have been designed to be transformed into an efficient and sustainable adsorbent for the removal of crystal violet (CV) dye from wastewater with up to 95% scavenging ability. BL have been characterized by Fourier transform infrared (FTIR) spectra, field emission scanning electron microscopy (FESEM), and zero point charge (pHzpc). The maximum adsorption capacity is 30 mg/g at pH 10. Physico-chemical parameters have been investigated concerning pH, contact time, initial concentration, and coexistent ions. Pseudo-second-order kinetics is followed best (R2 =0.999) signifying a chemisorption pathway. Besides, intra-particle diffusion plays a governing role in the film diffusion of crystal violet into the core of the adsorbent. Langmuir isotherm model fits best (R2=0.972) suggesting a uniform, monolayer, and homogeneous adsorption. Regeneration was successful with methanol (65%) and reusability was tested for three cycles and was found to retain activity up to 80%. Analysis of CV containing industrial effluent suggests that a 36.8% reduction is possible with BL. The effect of co-existent ions suggests little influence on the adsorption. Compared to other contemporary and relevant adsorbents, it can be concluded that BL can be exercised for the sustainable decontamination of CV-containing wastewater. Bambusa bambos, the giant thorny bamboo is an abundantly available plant throughout the year, has been successfully exercised using its fallen leaves to scavenge crystal violet, a cationic dye from water and wastewater. Up to 95% adsorption was noticed at ambient conditions, which when further extrapolated for industrial effluent analysis, shows a remarkable 36.8% decontamination/cycle. With an adsorption capacity of 30 mg/g, it enjoys an edge over contemporary phytosorbents. The process is free from any chemical treatment, green in nature, and sustainable. Abundant availability and economic viability allow an impactful application of fallen bamboo leaves for water and wastewater treatment in a lab-to-land sequence. [ABSTRACT FROM AUTHOR]

Developing highly efficient adsorbents toward trace pollutant analysis in complex biological samples is a challenge in analytical chemistry. Herein, NiO/ZnO-coated carbon microspheres (denoted by NiO/ZnO@C) with a well-defined core–shell structure were prepared through hydrothermal treatment and subsequent pyrolysis in air to enrich malachite green (MG) and crystal violet (CV). Hydrophilic carbon microspheres played an important role in the formation of core–shell NiO/ZnO@C, which may lead to the deposition of Ni2+/Zn2+ upon the surface via acidic chelating ligands. Based on the Langmuir model, NiO/ZnO@C demonstrated high adsorption capacities of 333.3 and 192.3 mg/g for MG and CV, respectively. Moreover, the NiO/ZnO@C composite served as a dispersive solid-phase extraction adsorbent to determine MG and CV in aquatic products combined with ultra-high performance liquid chromatography. High linearity was obtained for analyte concentrations from 5 to 500 μg/L with correlation coefficients (r) exceeding 0.9991. The limits of detection of the method were 0.50 μg/L (MG) and 0.35 μg/L (CV) with relative standard deviations less than 7.47%. Furthermore, the developed method was employed to determine MG and CV in aquatic products. [ABSTRACT FROM AUTHOR]

In this study, cottonwood seeds (CWS) were introduced as a novel, green, and low-cost biosorbents for the removal of crystal violet (CV) dye from aqueous solutions. To illustrate the characteristics of CWS, surface morphology, Fourier-transform infrared spectroscopy, field emission scanning electron microscopes, and energy dispersive X-ray spectroscopy techniques were employed. Important adsorption variables (i.e., equilibrium time, solution pH, CWS amount, CV concentration, and temperature) were systematically studied. Maximum CV dye adsorption was observed at pH 10 using 20 mg of the adsorbent. Different adsorption isotherms were investigated, and the results were more accurately consistent with the Langmuir model (R2 = 0.992). The maximum capacity of adsorption was 153.85 mg g−1 at 60 min. The kinetic data were examined by different models and a pseudo-second-order model supplied the best correlation between experimental data. Investigated thermodynamic parameters at different temperatures illustrated that the CV adsorption procedure was spontaneous and endothermic with an increase in entropy. The percentage removal and the relative standard deviations for the real sample analysis were in the range of 89–98% and 4.9–9.5%, respectively. High adsorption capacity and low equilibrium time demonstrated that CWS is an impressive biosorbent for dye pollutants uptakes from aqueous solutions and real industrial wastewater samples. A novel, green, available, and low-cost cottonwood seeds were introduced for the removal of crystal violet from aqueous media. In terms of adsorption capacity and contact time, cottonwood seeds show excellent performance compared to the other low-cost biosorbents previously reported for the adsorption of the organic dye from wastewater. The use of cottonwood seeds to remove environmental pollutants has not been introduced yet. [ABSTRACT FROM AUTHOR]

Equisetnm arvense plant extract was used for preparing amorphous SiO2. For preparing of SiO2/zeolitic imidazolate framework-8 (ZIF-8) nanocomposite by solvothermal method, the synthesized SiO2 was added to synthesis mixture ZIF-8. The photocatalytic activity of SiO2/ZIF-8 was investigated systematically by degrading crystal violet as a cationic dye under UV light irradiation. The photodegradation of crystal violet by SiO2, ZIF-8 and SiO2/ZIF-8 samples was 13.7%, 25.6% and 75.6% during UV-light irradiation for 15 min. Among synthesized samples (SiO2, ZIF-8 and SiO2/ZIF-8), the SiO2/ZIF-8 exhibited highest photocatalytic activity and improved stability compared to pure SiO2 and ZIF-8. As evidenced from SEM and TEM images, ZIF-8 particles without aggregation located over SiO2. The enhancement of the photocatalytic activity is due to the fact that the introduction of insulator SiO2 in SiO2/ZIF-8 composites can modify the surface state of the composite; more importantly, the energy level of SiO2 can help accelerate the separation and transfer of electron-hole pairs of ZIF-8. The SiO2/ZIF-8 photocatalyst did not show any obvious loss of photocatalytic activity during five cycles, which indicate that the heterostructured photocatalyst was stable and can be used repeatedly. [ABSTRACT FROM AUTHOR]

Copper ferrite (CuFe2O4, CF) and silver-doped copper ferrite (Ag-CuFe2O4, ACF) were prepared via co-precipitation method. While nano-composite of ACF with rGO was prepared by ultra-sonication approach. Degradation of crystal violet (CV) and benzoic acid (BA) by CF, ACF, and ACF@rGO was conducted under sunlight. Because of tremendous stability and immense surface area of rGO, it shows good ability to transfer electrons during photocatalysis.Band gap for CF and ACF were tuned having values 1.36 and 1.67 eV. Ag-CuFe2O4@rGO has exhibited greater photo-catalytic activity than a bare and doped sample. 82.7% and 48.4% were degradation % of CV and BA by Ag-CuFe2O4@rGO respectively. Ag-CuFe2O4@rGO showed 1.3 times higher efficiency than bare CuFe2O4. ACF was sonicated with rGO and composite was formed which was not reported before and I was the novelty of this paper. The photodegradation ability and cyclic stability etc. was increased after the formation of composite. [ABSTRACT FROM AUTHOR]

Olive oil industry produces a large quantity of solid effluent (olive pomace OP) which can be used to get an economic profit. At the same time, crystal violet has been stated as a recalcitrant dye that perseveres in environment for extended time and bearings noxious influences in environment. In this work, olive pomace (OP) was treated by sodium hexametaphosphate (SHMP) and used as a low cost and eco-friendly biosorbent (SHMP-OP) for the removal of crystal violet (CV) from aqueous solutions. The prepared adsorbent characterised thru infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD) scanning electron microscope (SEM), energy dispersive X-ray analysis (EDX) and zero-point charge (pHzpc). In the batch adsorption process, the effect of different factors like pH, adsorbent amount, initial dye concentration, temperature and contact time, on the removal of CV dye from aqueous solutions using SHMP-OP was examined. The results showed that maximum dye adsorption was found at pH 7 after equilibrium contact time of 50 min with a biosorbent dosage of 120 mg at temperature of 25°C. Langmuir and Freundlich isotherms were applied for the interpretation of experimental data. The isotherm studies showed that Langmuir was found to be best fitted with 271.003 mg/g maximum adsorption capacity. Also, successful desorption study using 0.5 mol/L of HCl has greatly promoted the spent adsorbent to be further used up to four consequent adsorption/desorption cycles. These results revealed that SHMP-OP is effective, eco-friendly and low-cost biomaterial for CV removal from aqueous media. [ABSTRACT FROM AUTHOR]

Glutamine-assisted SnO2 nanorods with an average crystallite size of 48.38 nm were facilely fabricated using the hydrothermal procedure. Also, the fabricated sample was characterised using XRD, FT-IR, FE-SEM, HR-TEM, and UV-Vis spectroscopy. The glutamine deeply influences the crystallite size and morphology of the fabricated SnO2. Moreover, the UV–Vis shows a broad absorption spreading into the visible light region. Furthermore, depend on Tauc's plot, the optical energy gap of the fabricated sample is 2.85 eV. Besides, the photocatalytic activity of the fabricated sample was examined by observing the degradation of crystal violet dye under visible light irradiation. The photodegradation efficiency of crystal violet dye over glutamine-assisted tin oxide nanorods is 97.38% within 60 min. Additionally, the fabricated photocatalyst is characterised by the reusability for several times without losing its efficacy. [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 this research, the ability of synthesized graphene oxide nanoparticles (GONPs) for the removal of crystal violet (CV) dye from the aqueous solutions is described. The structure of the GONPs was characterised with FTIR, SEM, TEM and XRD techniques. The interaction and significance of parameters such as the amount of adsorbent, pH, ultrasound time and initial concentration of CV dye on the removal efficiency of the dye were studied by Central Composite Design (CCD) coupled with Response Surface Methodology (RSM). The utmost adsorption was obtained at the variables set of 0.6 g/L GO, pH of 8, 30 min of sonication and 80 mg/L of dye concentration at room temperature. The efficiency of adsorption was obtained more than 90% under the optimized parameters of the process. The results specify that the R2 value was 0.802, while the adjusted R2 was 0.629. The equilibrium data fitted better to the Langmuir model than the Freundlich model, while the Langmuir monolayer adsorption capacity was 166 mg g−1 for CV dye. The kinetic studies confirmed that the pseudo-second-order model was best fitted for the adsorption process of the dye. [ABSTRACT FROM AUTHOR]

In this work, Bi@Cd MOF has been synthesized by a hydrothermal route and characterized by the XRD, BET, SEM, EDS and elemental mapping analysis. Adsorption behaviors of crystal violet on the Bi@Cd MOF were studied in various conditions and the adsorption capacity of 175.4 mg/g after was obtained. The effect of adsorbent dose (1–7 mg), initial concentration (6–14 ppm), pH (2–6), temperature (10–50 °C), stirring speed and adsorption kinetics were investigated by batch method. The experimental adsorption isotherm was described by Dubinin-Radushkevich model. The adsorption thermodynamic studies in the temperature range of 283 to 333 K were shown the exothermic nature of adsorption. The removal efficiency of crystal violet using Cd MOF and Bi@Cd MOF showed that the removal efficacy improved in biological wastewater (from 14 to 50%), industrial wastewater (from 8 to 56%), mineral water (from 28 to 71%) and drinking water (21–68%). It was demonstrated that prepared adsorbent could be effectively used for the removal of crystal violet from aqueous solutions. [ABSTRACT FROM AUTHOR]

This study reported the desorption of adsorbed crystal violet (CV) dye on the argan nutshell (ANS) and almond shell (AS) using nitric acid (HNO3) as a desorbing agent and their reusability to remove the CV in multiple consecutive adsorption-desorption cycles. The prepared adsorbents were characterized using FTIR and SEM analysis. Different desorbing agents (HCl, HNO3, H3PO4, CH3COOH, NaOH, H2O, H2O (pH = 2), and H2O (pH = 11)) were tested to determine the best eluent. The effect of experimental parameters, such as CV-adsorbent dose (4–40 g L−1), contact time (0–180 min), and HNO3 concentration (0.01–2 M) on the desorption of the CV from CV-ANS and CV-AS was studied. The HNO3 (0.1 M) solution was an excellent eluent for the CV desorption from CV-ANS (98.21%) and CV-AS (98.60%) using 16 g L−1 of CV-adsorbent dose at 23 ± 1 °C for 60 min. The pseudo-second-order kinetic model well-exemplified experimental data. Excellent regeneration reusability of ANS and AS for the CV removal for six consecutive adsorption–desorption cycles. This study showed that argan nutshell and almond shell as low-cost adsorbents have tremendous potential for removing the CV in multiple consecutive adsorption-desorption cycles as an alternative eco-friendly process. [ABSTRACT FROM AUTHOR]

Bacteria form biofilms by attaching to materials. The formed biofilm has various influences on daily life and industry, positively or negatively. Therefore, the biofilm should be observed and controlled in an appropriate manner. There are numerous developed methods to evaluate biofilms. However, many of them have been not appropriate from the viewpoint of industrial application since they are difficult to be handled and the associated pieces of equipment are very expensive. Therefore, in this study, the authors focused on staining methods to evaluate biofilms. Crystal violet is well known to stain negatively charged parts of polymeric substances, such as polysaccharides and other polar polymers. Thus, the amount and contents were expected to evaluate reliably. In this study, the authors compared Raman shifts and colour measurements for biofilms formed on four metallic materials by Escherichia coli and Staphylococcus epidermidis. It could be confirmed that staining by crystal violet could predict the amounts of biofilms, and the contents ratio (particularly the contents of polysaccharides) to some extent. [ABSTRACT FROM AUTHOR]

In this work, coal bottom ash was modified by alkaline fusion route in order to improve its pore properties and make it a potential adsorbent to remove crystal violet dye from aqueous medium. The solids were characterized and posteriorly subjected to kinetic, isotherm, and thermodynamic studies, as well as regenerated and reused for five adsorption tests. The alkaline fusion step resulted in the amorphization of material and generation of high surface area (102 m 2 g −1) and pore volume (0.180 cm 3 g−1), resulting in superior performance compared to the raw material. Kinetic and equilibrium studies showed that the adsorption process was better adjusted by the pseudo-second order and Langmuir models, respectively. The maximum adsorption capacity at equilibrium was 177. 37 mg g−1, with the adsorptive step occurring spontaneously and endothermically. The adsorbent maintained notable levels of dye removal after five consecutive cycles of thermal regeneration and reuse. Besides, the adsorbent was able to remove 64% of the colour of simulated industrial wastewater. Therefore, the alkaline fusion step proved to be a route capable of transforming the coal bottom ash into an adsorbent with improved textural and adsorptive properties. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of a novel bio-nanocomposite (Alg-Cst/Kal) for the effective removal of the dye "Crystal Violet" from its aqueous solutions. In order to observe the surface morphology and functional groups, the bio-nanocomposite was characterized using various techniques such as SEM, EDX, TEM, FTIR, XRD, and TGA. The effect of parameters like contact time, pH, concentration and temperature on the adsorption of the dye over adsorbent has been studied in detail. The dye – adsorbent system has been tested over various isotherm models and found to follow the Freundlich adsorption isotherm model at 303 K. The developed bio-nanocomposite material exhibits an excellent adsorption toward Crystal Violet with a maximum adsorption capacity of 169.49 mg.g−1. The experimental data has been further validated by applying various kinetic models and the pseudo-second order kinetic model was the best suited model. The calculated rate constant values ranged from 0.0046 to 0.0204 g.mg−1.min−1 for different dye concentrations. The positive values of change in enthalpy, ΔH° (9.765 kJ.mol−1) and change in entropy, ΔS° (0.0565 kJ.mol−1.K−1) obtained through thermodynamic studies demonstrate the endothermic nature and spontaneity of the adsorption process, respectively. The adsorption capacity of the adsorbent for the removal of the Crystal Violet dye was also compared with other adsorbents and found maximum. Novelty statement A novel bio-nanocomposite is synthesized by modifying the biopolymer alginate, cysteine and mixing the clay, kaolinite (Kal). The adsorption abilities of the material was tested the on the cationic hazardous dye, Crystal Violet. The material is novel and no attempt has so far been made to examine its batch adsorption abilities to remove hazardous dyes from the wastewater. The results are highly encouraging as out of all the adsorbents tested so far highest adsorption of the dye is observed in the present studies. [ABSTRACT FROM AUTHOR]

A new dispersive liquid-liquid micro-extraction (DLLME) was developed to extract malachite green (MG) and crystal violet (CV) in water samples using a hydrophobic deep eutectic solvent (DES) before their determination by high performance liquid chromatography (HPLC). The hydrophobic DES was prepared by mixing benzyltriethylammonium chloride (BTEAC) as acceptor of hydrogen bond and thymol as donor of hydrogen bond at 70ºC for 10 min. Influencing factors on DLLME were considered and optimised. In optimal conditions, the limit of detection (LOD) for MG and CV was 0.03 and 0.05 µg L−1, respectively. Calibration curve for both dyes was linear in the range 0.2–500 µg L−1 with a correlation coefficient greater than 0.99. Also, pre-concentration factor for MG and CV was 95 and 100, respectively. The within-day and between-day precision at concentration levels of 10 and 100 µg L−1 were less than 7%. Finally, the applicability of the proposed method was evaluated through the analysis of water samples and the relative recoveries obtained (90.0–97.5%) were acceptable. [ABSTRACT FROM AUTHOR]

Lignin is a type of biomass that is generally found in nature and has a wide range of applications as a functional material. A novel sorbent, aminated lignin (AL), was synthesized in a one-step method to improve its adsorption capabilities. The AL was characterized through Brunauer–Emmett–Teller surface area analysis, thermogravimetric analysis, scanning electron microscopy, and zeta potential analysis. AL was small in size and had a clear obvious porous structure with a surface area of 47.1 m2·g−1, nearly ten times larger than that of kraft lignin, which was 4.75 m2·g−1. AL was utilized for the adsorption of cationic dyes (crystal violet, CV) and anionic dyes (Congo red, CR) from aqueous solutions. The maximum CV and CR adsorption of AL at 25 °C were 97.09 and 129.87 mg·g−1, respectively. Five factors affecting adsorption including adsorption time, pH of dyes, initial dye concentration, AL dosage, and adsorption temperature were investigated. The fitting results of the two dyes revealed that the adsorption process followed pseudo-second-order kinetics and the Langmuir isotherm equation. This study demonstrates that AL can be used as a low-cost adsorbent for both cationic and anionic dyes from wastewater. [ABSTRACT FROM AUTHOR]

A novel zwitterionic superabsorbent polymer hydrogel poly(MEMA-DMAPS) was synthesized using three different combinations of 2-(N-morpholino) ethyl methacrylate (MEMA) and 3-((2-methacryloyloxy)ethyl) dimethylammonio) propane-1-sulfonate) (DMAPS) monomers in the polymerization mixture. For characterizing its ionic dye adsorption, Congo Red (CR) and Crystal Violet (CV) were used as anionic and cationic dye models, respectively. The pH of the aqueous solution was shown to be the most decisive variable in the adsorption mechanism. The hydrogel (DM-1) possessed a point of zero charge (PZC) at pH 6.9. At pH values above or below the PZC, the hydrogel showed excellent selectivity for oppositely charged dyes. The adsorption capacity was found to be 370 mg g−1 at pH 2, and 139 mg g−1 at pH 10 for CR and CV, respectively. The positive values of enthalpy change calculated at temperatures in the range of 25 °C to 55 °C reflect that the removal processes of both dyes were endothermic. The standard Gibbs free energy (ΔGo) values at all temperatures studied indicated that the adsorption process occurred spontaneously and nonspontaneously for CR and CV, respectively. [ABSTRACT FROM AUTHOR]

Using the co-precipitation oxidation method and metal salt precursors, pure MFe2O4 (M = Co, Zn, Cu and Ni) photocatalysts were prepared co-precipitation method. The several properties of photocatalysts were studied. In sunlight and at neutral pH, all photocatalysts degraded crystal violet and performance ranking was NiFe2O4 < CoFe2O4 < CuFe2O4 < ZnFe2O4. Among these photocatalysts, ZnFe2O4 showed the highest photocatalytic degradation performance due to the smallest particle sizes, which were widely distributed. More channels were obtained due to the small pore volume providing a high number of active sites with optical band gap values of 1.69–2.55 eV. The photocatalytic degradation was an effect of the ratio of Zn/Fe, photocatalyst loadings, and calcination temperature. Calcination time and reaction duration were studied. The photocatalytic degradation reaction was almost completed within 24 h using Zn:Fe (1:2). The reaction followed the first-order rate constant. Photocatalysts were stable for seven times recycles. [ABSTRACT FROM AUTHOR]

Gadolinium doped bismuth ferrite (Gd:BFO) nanoparticles were synthesized using an auto combustion method. The structural analysis of the prepared Gd: BFO nanoparticles showed that all samples exhibit a rhombohedral structure. The optical analysis shows the doping of Gd ions reduces the band gap value of BFO from 2.21 eV to 2.17 eV. The presence of Fe-O stretching vibrations is confirmed by Fourier transform infrared (FTIR) spectroscopic analysis. The magnetic hysteresis (M-H) analysis shows a weak ferromagnetic nature for the prepared BFO samples and the value of saturation magnetization (Ms) increases upon an increase in the Gd doping concentration. The dielectric analysis shows that the doping of Gd ions in BFO has a notable control in the dielectric loss of the prepared BFO nanoparticles. It was observed the Gd (2 wt%) doped BFO nanoparticles exhibit 84.5% degradation toward crystal violet (CV) dye under visible light irradiation. The formation of trap levels due to Gd 4f state and the role of superoxide anion ( O 2 − ) and OHo radicals toward the degradation of CV dye were analyzed. [ABSTRACT FROM AUTHOR]

A new type of binuclear cobalt phthalocyanine was synthesized and loaded on MIL-100(Fe) by impregnation to synthesize a new type of binary composite catalyst BiCoPc/MIL-100(Fe). Through X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), N2 physisorption measurements and other characterizations, the composite catalyst was applied to photocatalytic degradation of crystal violet dye pollutant under ultraviolet irradiation. Compared with BiCoPc or MIL-100(Fe) separately, the synthesized BiCoPc/MIL-100(Fe) composite material significantly enhanced the photocatalytic degradation of crystal violet (CV), with efficiency as high as 91.56%. The synergistic effect between BiCoPc and MIL-100(Fe) improves the light utilization efficiency. The catalytic activity of the central ion of the composite material and the larger specific surface area accelerate the charge transport and reduce charge recombination. By preparing a composite catalyst based on a MOF to achieve photocatalytic degradation provides a new strategy. [ABSTRACT FROM AUTHOR]

Nickel oxide (NiO) nanoparticles were prepared by thermal decompositions of nickel acetate tetrahydrate and bis(acetylacetonato) nickel(II) complex at 500°C in air atmosphere. The thermal decomposition of nickel acetate tetrahydrate produced NiO and the thermal decomposition of bis(acetylacetonato) nickel(II) complex afforded a metal-metal oxide composite material (Ni/NiO). The prepared materials were characterised for assigning their structural and surface properties using the Fourier transform infrared (FT-IR), the X-ray diffraction (XRD), the scanning electron microscopy (SEM), the transmission electron microscopy (TEM), and the thermal analysis (TGA, DTA). The XRD analysis revealed a cubic crystalline structure of NiO and a face-centred cubic structure of Ni. The crystallite size of NiO nanoparticles found to be within 21–63 nm. The XRD analysis of the Ni/NiO composite proved a molar ratio of 10:1 for Ni/NiO. The prepared NiO nanoparticles were studied for the adsorptive removal of the crystal violet dye (CV) from the aqueous solutions as a function of pH of the aqueous solution, initial CV concentration, adsorbent dose, contact time and temperature. The highest adsorbed amount obtained is 79.13 mg/g at pH 9–10 and the adsorption reached equilibrium after 20 min. The equilibrium data was analysed using the Langmuir and the Freundlich adsorption isotherm models and the maximum monolayer adsorbed amount of 53.19 mg/g. [ABSTRACT FROM AUTHOR]

Sigle phase scheelite-monoclinic BiVO4 materials with different morphologies were successfully fabricated via a facile hydrothermal process by controlling pH of the precursor. The photocatalytic properties of the as-prepared materials were assessed via the photodecomposition of crystal violet (CV) solution under a 60 W LED (Cree-L6) visible light irradiation. The Langmuir-Hinshelwood model was utilized to present kinetic behavior. The obtained BiVO4 exhibited a monoclinic crystalline structure and narrow bandgap energy (Eg = 2.3–2.6 eV), which were confirmed by the X-ray diffraction (XRD), Raman and UV-vis diffuse reflectance spectra (UV-vis DRS) results. From the scanning electron microscopy (SEM) results, BiVO4 morphologies could be facilely controlled by turning the pH value of the precursor. When pH = 0.3, the BiVO4 products showed spherical morphologies with particle sizes in the range of 1–5 µm. Rod- and spherical like-BiVO4 products were obtained when the pH of the precursor was adjusted to 3. Moreover, BiVO4 with nanoparticles could be prepared under the pH of 5–7, whereas leaf-like morphologies could be achieved when pH = 9. The photocatalytic test showed that the adsorption equilibrium constant depended on the morphologies of the BiVO4 products and the reaction rate constant was reached the highest level at pH = 3. This outcome indicated that the enhanced performance of BiVO4 significantly depended on the morphologies of the BiVO4 products and the effective suppression of photo-excited electrons and holes. [ABSTRACT FROM AUTHOR]

Hexahydroxy strontium stannate nanorods were synthesized via a facile hydrothermal route and characterized by X-ray diffraction, electron microscopy, X-ray photoelectron spectroscopy and solid UV-Vis diffuse reflectance spectroscopy. The nanorods with single crystalline hexagonal SrSn(OH)6 phase have lengths of several μm and diameters of 50–150 nm. The formation process was investigated by observing the evolution of the morphology and structure under different conditions. The band gap is 3.76 eV. The photocatalytic performance of the nanorods was evaluated under ultraviolet light irradiation with crystal violet in aqueous solution which can be entirely photo-degraded within 6 hours. Anti-interference experiments showed that hydroxyl radicals, holes, and superoxide radicals are involved in the sdegradation of crystal violet. [ABSTRACT FROM AUTHOR]

In the current work, Cu-doped Nickel ferrites (CuxNi1−xFe2O4) integrated on carbon nanotubes (CNTs) were synthesized by wet-chemical method. The synthesized composite CuxNi1−xFe2O4/CNTs along with pristine NiFe2O4 and CuxNi1−xFe2O4 were characterized by X-rays diffraction (XRD), Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). XRD data confirmed the synthesis of NiFe2O4 and CuxNi1−xFe2O4 with tetragonal lattice structure. The crystallite size varied from 26 to 35 nm with the substitution of Cu+2 ions in NiFe2O4 while CuxNi1−xFe2O4/CNTs showed moderate crystallite size of 32 nm. SEM analysis showed spherical nanoparticles of CuxNi1−xFe2O4 which transformed to aggregated blocks on combining with high surfaced CNTs. The conductivity of pure NiFe2O4 raised up to 0.028 and 0.22 S/m upon modification to CuxNi1−xFe2O4 and CuxNi1−xFe2O4/CNTs, respectively. CuxNi1−xFe2O4/CNTs showed maximum degradation efficiency (92.9%) for CV, which was 1.4 and 1.8 folds higher than NiFe2O4 and CuxNi1−xFe2O4, respectively. [ABSTRACT FROM AUTHOR]

The powdered biomass of paddle cactus (Tacinga palmadora), a rustic plant of great occurrence in the driest regions of Brazil, was evaluated as a low-cost adsorbent to treat textile effluents containing crystal violet (CV) dye. The powdered paddle cactus (PPC) was mainly composed by lignin and holocellulose, as well as, a variety of functional groups. Best results for CV adsorption were found using an adsorbent dosage of 0.5 g L−1 at solution pH equivalent to 10.0. Fast adsorption kinetics was verified, being the equilibrium reached within 100 min, and the curves were well modeled by the pseudo-first-order model. The isotherms were well-represented by the Langmuir model. The maximum adsorption capacity was 228.74 mg g−1 at 328 K. The estimated thermodynamics parameters were ΔG0T = 328K of –9.08 kJ mol−1, ΔH0 of 12.44 kJ mol−1, and ΔS0 of 0.065 kJ mol−1 K−1. In addition, PPC was able to treat a simulated textile effluent containing organic and inorganic compounds, reaching 93% of color removal efficiency. These findings show that powdered paddle cactus can be applied as potential low-cost adsorbent to treat textile effluents containing CV. [ABSTRACT FROM AUTHOR]

Micro/nano-structural polyaniline materials were prepared by using thin glass tubes as template in the presence of β2-SiW11Mn and ammonium persulfate, which were used as dopant and oxidant, respectively, in this system. The materials were characterized by IR, UV-Vis, XRD, TG-DTA and SEM techniques. The photocatalytic performance of polyaniline, β2-SiW11Mn and β2-SiW11Mn/PANI composite obtained was investigated using photodegradation of crystal violet as model reaction. The results showed that the photocatalytic activity of β2-SiW11Mn/PANI composite was much higher than polyaniline and β2-SiW11Mn due to a synergy between the two. The degradation rate of crystal violet was 91.19%. [ABSTRACT FROM AUTHOR]

A novel ZnO film of two dimension ordered spherical structure has been synthesised via RF magnetron sputtering method using monodispersed polystyrene spheres as template. The 2D-ordered spherical ZnO film was characterised by SEM, TEM, XRD, and DRUV–vis. In this work, growth process and photocatalytic ability of the 2D-ordered spherical ZnO film were studied. The 2D-ordered spherical film shows 2.3 times higher catalytic performance than that of the reference ZnO flat (R-ZnO) film. [ABSTRACT FROM AUTHOR]

In this work, the study of hydrogen peroxide (H2O2) electro-generation using graphite from exhausted batteries (Gr-Bat) was conducted. Linear sweep voltammetry and electrolysis experiments were carried out in a single compartment electrochemical cell. Study of the possibility to use this electrode revealed that it presents, as vitreous carbon (VC) electrode, a reduction of oxygen with two successive waves (bi-electronic reduction). The first wave corresponds to the reduction of O2 to H2O2, while the second one corresponds to the reduction of H2O2 to H2O. The cathodic potentials for electro-generation of H2O2 appeared at −600 and –700 mV vs. Ag/AgCl for Gr-Bat and VC electrodes, respectively. Subsequently, electrolysis experiments were conducted by imposing the potentials required for H2O2 formation. The effect of several operating parameters on H2O2 production, such as the nature and concentration of the electrolyte, the pH, the presence of ferrous ions and O2 injection were studied using Gr-Bat and VC electrodes, respectively. For both electrodes, the acidic medium was more favorable for H2O2 electro-generation. The oxygen injection in solution promoted an increase of H2O2 concentration, but its effect was more pronounced in the case of VC electrode. Application for crystal violet degradation by electro-Fenton revealed that Gr-Bat had the best purification performance. A removal rate of 73.18% was obtained with Gr-Bat electrode against 62.27% with VC electrode for an electrolysis time of 120 min. This study has demonstrated the possibility of recycling Gr-Bat by using them as cathode materials in the electro-Fenton process. [ABSTRACT FROM AUTHOR]

In the face of water scarcity and more strict environmental regulation, water treatment is a demand and reuse is being encouraged in diverse production processes. Advanced treatments, such as adsorption, may be indicated for specific and/or recalcitrant contaminants removal, such as dyes, present in textile industries wastewater, for example. However, the conventional adsorbents cost may be unattractive for such a purpose. In this context, bone char, 0.5–1.4 mm particle size, mesoporous structure, produced from tannery, food and cattle breeding waste, was tested to remove crystal violet dye from synthetic effluent, in a lab scale fixed bed adsorption column. A complete removal was observed up to 74 min of column operation. The greatest adsorption capacity (qo = 20.63 mg·g−1) was observed for the lowest flow rate evaluated (Q = 15.4 ± 0.8 mL·min−1) and intermediate bed depth (h = 24 cm) at 27.1 ± 0.9 °C. At the same operational conditions, the experimental breakthrough curve was better predicted by Yan model (qo = 20.42 mg·g−1; a = 1.667; b = 2.93 and R2 = 0.955) compared to Thomas model (qo = 22.44 mg·g−1; kTH = 0.056 mL·mg−1·min−1 and R2 = 0.878). [ABSTRACT FROM AUTHOR]

In this study, Anatolian black pine (ABP, Pinus nigra Arnold.) was evaluated as biosorbent for removal of crystal violet (CV) from aqueous solution. The influence of operational parameters including solution pH, initial CV concentration, biosorbent dosage, contact time, and temperature were studied in batch systems. The adsorption data followed well Langmuir isotherm with a maximum biosorption capacity of 12.36 mg/g. The equilibrium data were better fitted with pseudo-second-order kinetic model (R2 ˃ 0.99). Moreover, the thermodynamic parameters indicated that the CV biosorption was feasible, spontaneous, and endothermic process. This study showed that ABP (Pinus nigra Arnold.) can be used to remove CV from aqueous solutions. [ABSTRACT FROM AUTHOR]

Detailed procedure to form gold (Au) thin films from surfactant free Au nano-particle dispersed aqueous solution prepared by solution plasma processing was investigated for surface-enhanced Raman scattering (SERS) spectroscopy measurement. The averaged diameter, thickness, and the weight of each Au thin film in our experimental conditions from 40 mL of 1% Au dispersed aqueous solution, were evaluated to be around 2.4 mm, 4.6 μm and 0.4 mg, respectively. SERS spectra of dye molecule (crystal violet: CV) adsorbed on Au thin film and silver (Ag) substrate were successfully measured upon excitation at 532 nm of solid type laser and 632.8 nm of He-Ne laser, respectively. These SERS spectra of CV adsorbed both on Au and Ag surfaces were coincided with each other, and the intensity from Au surface was unexpectedly much stronger as compared to those from Ag surface. The possible application of Au thin film for SERS platform on solid/liquid interfaces was demonstrated by observation of SERS spectra from p-nitrothiophenol (PNTP) adsorbed on Au thin film/aqueous solution interface. [ABSTRACT FROM AUTHOR]

Food colorants are inalienable part of human life. Since ancient times, they have become firmly established and have undergone a number of changes. During this time, the attitude towards them has changed. The desire to color the food now raises questions about the various side effects of their use. With the development of methods of toxicology and obtaining data on the toxicity of food coloring, restrictions and standards for their content in food have emerged. The development of methods for the analysis of dyes in various food products is becoming increasingly in demand. Development of screening immunoanalytical methods such as enzyme-linked immunoassay and immunochromatographic one suitable for simultaneous analysis of a large number of samples at the same time allows to avoid serious costs when operating the chromatographic equipment. Reduction of the analysis time and simple sample preparation is what unites immunoassay techniques. This review shows the possibilities of modern immunoanalytical methods for analyzing samples and determining food dyes belonging to different classes. [ABSTRACT FROM AUTHOR]

An enzymatic reaction using glucose oxidase (GOx) was applied for continues production of hydrogen peroxide and organic acid inPhanerochaete chrysosporiumcultures for use simultaneously in catalytic cycle of peroxidases. Decolorization efficiency of crystal violet (CV) as a model pollutant was investigated in 16 d old cultures which overproduced manganese peroxidase (MnP) in response to daily GOx addition and control cultures (i.e. no GOxwas added). However, the ability of overproduced cultures in decolorization of CV was not increased significantly, through addition of GOx(300 U/L) + glucose (10 Mm) to the culture medium at the start of decolorization, the time needed to obtain 87 ± 0.5% removal of CV was reduced 10.7-fold in compared with the control culture. The best GOxconcentration in culture medium for more efficient decolorization was obtained to be 300 U/L. These findings indicated that GOx in the presence of glucose could increase the degradation of CV not only by inducing ligninolytic activity in cultures but also as a subsidiary source forin situH2O2and organic acid production for catalytic activity of peroxidases inP. chrysosporiumcultures. [ABSTRACT FROM PUBLISHER]

Context:Equisetum giganteumL. (Equisetaceae) is an endemic plant of Central and South America used in traditional medicine. Natural drugs have been frequently used in the treatment of a myriad of diseases, proving to be an alternative to synthetic chemicals, and have been intensively studied in the prevention of sicknesses, including oral diseases. Objective:This study evaluated thein vitroantiadherent activity ofE. giganteumextract againstCandida albicansbiofilms. Materials and methods:Crystal violet and colony-forming units assays were used to quantify the total biofilm biomass and biofilm living cells on a denture base acrylic resin pretreated with hydroethanolic extract ofE. giganteumin different concentrations (50, 25, 16, 8, and 4 mg/mL), after 24 h of biofilm development. Results:Equisetum giganteumaffected biofilms by reduction of biomass and living cells per area of acrylic specimens. The results revealed reduction of 15–44% of the biofilm mass and reduction of numbers of colony-forming units (CFUs) present in biofilms (79%) compared to the untreated control (CTRL/PBS). At all concentrations, it demonstrated important antiadherent activity onCandida albicansbiofilms, the main microbe in denture stomatitis. Discussion and conclusion:The present findings show thatE. giganteumantimicrobial effects may qualify the extract as a promising natural alternative for topical treatment or prevention of denture stomatitis. The usage of drugs made of natural products shows advantages in relation to synthetic drugs on the market, such as lower cost, lower toxicity, and in relation to the occurrence of microbial resistance. [ABSTRACT FROM PUBLISHER]