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Eragrostis plana Nees (EPN) was used as new and eco-friendly adsorbent for the removal of crystal violet dye (CV) from aqueous solution. Specific surface area (BET), scanning electron microscopy (SEM), infrared spectroscopy (ATR-FTIR), point of zero charge (pH PZC ), and modified Boehm titration method were used to characterize the EPN material. The effects of initial pH of solution, adsorbent mass, contact time and initial dye concentration, and temperature were studied in batch adsorption mode. Kinetic data were evaluated by pseudo-first-order and pseudo-second-order models. The result exhibited that pseudo-second-order model well described the adsorption kinetics of CV onto EPN. Langmuir, Freundlich, and Sips isotherm models were used for analysis of the isothermal data. The equilibrium data of adsorption of CV onto EPN was better fitted with the Sips isotherm. Based on the Sips isotherm model, the maximum adsorption capacity was 76.20 ± 1.20 mg g -1 at 333 K. A high desorption of CV from EPN was obtained using 1.00 mol L -1 of CH 3 COOH as eluent. The thermodynamic data indicated that the adsorption was spontaneous, endothermic, and physical process. EPN can be used as alternative adsorbent to remove CV from aqueous solution.

Activated carbon prepared from sawdust, magnetized by magnetite nanoparticles, was used for the adsorption of crystal violet dye (CV) from an aqueous solution. The nanocomposite Fe3O4/AC was characterized by means of XRD, FTIR, SEM, and BET analyses, along with size distribution and zeta potential assessments. The pHPZC and BET surface area of Fe3O4/AC were 6.05 and 160 m2/g, respectively. The study identified the optimum pH condition as pH 9.0, with a maximum removal efficiency of 100%. Kinetic studies were conducted, and the data fitted well with the pseudo-second order equation. The synthesized Fe3O4/AC exhibits a maximum uptake capacity of 76.0 mg/g. Overall, this nanocomposite provides an effective type of adsorbent for removing CV dye. Its primary advantage lies in its simple synthesis compared to other magnetic materials, along with its economic viability, rapid preparation, and environmental friendliness. [ABSTRACT FROM AUTHOR]

In this work, the application of central composite design (CCD) was used to optimise the synthesis of volcanic ash/ rice husk ash-based phosphate geopolymers. The effects of three factors namely, volcanic ash fraction, rice husk ash fraction and phosphoric acid concentration on porosity structure were investigated based on methylene blue index and iodine index as response variables. At optimized conditions of 3.72 g volcanic ash, 1.97 g rice husk ash and 5 M phosphoric acid concentration, desirable porosity structure was attained. The optimized geopolymer and their precursors were characterized by XRF, FTIR and XRD and applied to sequester crystal violet dye (CV) from water. The equilibrium data were described by the Langmuir isotherm with a maximum adsorption density of 14.6 mg/g. Adsorption rate followed pseudo-second-order kinetics. Notably, maximized porosity structure was attained at low acid concentration (5 M), a significant outcome in terms of cost and safety for pilot scale application. [ABSTRACT FROM AUTHOR]

In this study, chromium‐based metal–organic framework (MIL‐101(Cr)) was incorporated into polyvinyl alcohol nanofibers (PVA NFs) via green electrospinning followed by heat treatment to fabricate MIL‐101(Cr)@PVA NFs composite without the need for any organic solvent or other dispersants. The fabricated MIL‐101(Cr)@PVA NFs were comprehensively characterized using a suite of common techniques. Morphological characteristics of MIL‐101(Cr)@PVA NFs showed a fibrous structure with an average diameter of 228 ± 37 nm and decorated with MIL‐101(Cr) particles arranged in a nanoneedle‐like pattern. Subsequently, its adsorption efficiency towards the cationic crystal violet dye (CV) was evaluated through batch adsorption experiments. The influence of various experimental parameters on CV removal efficiency was systematically optimized using a factorial design approach. The Langmuir isotherm and kinetic pseudo‐second‐order (PSO) model provided an excellent fit to the adsorption equilibrium data, indicating a maximum adsorption capacity (qmax) of 344.18 mg/g for MIL‐101(Cr)@PVA NFs compared with 83.94 mg/g for pristine PVA NFs. Furthermore, the MIL‐101(Cr)@PVA NFs composite demonstrated excellent reusability and stability, maintaining a significant portion of its removal capacity even after six adsorption–desorption cycles. These findings highlight the potential of the fabricated composite as a highly efficient and reusable adsorbent for CV removal from wastewater treatment applications. Highlights: The MIL‐101(Cr)@PVA NFs nanocomposite fabricated by electrospinning technique.The MIL‐101(Cr) particle arranged in a nanoneedle‐like pattern in the PVA NFs.Incorporation of MIL‐101(Cr) improved qmax of PVA by 391.5%.The MIL‐101(Cr)@PVA NFs membrane has excellent stability and reusability. [ABSTRACT FROM AUTHOR]

In the present study, grafting of acrylic acid and itaconic acid copolymer onto carboxymethyl cellulose backbone was performed by a free radical polymerization approach to decontamination of crystal violet and malachite green from aqueous media. To promote removal efficiency, various amounts of Cloisite 30B nanoclay were integrated into the hydrogel matrix, and the optimum value based on the removal performance was obtained 6 wt.%. The optimum pH values, initial concentration, and contact time were determined to be 7, 30 mg/L, and 140 min. The kinetic and equilibrium data were well defined by quasi-second-order and Langmuir models. The maximum adsorption capacity of hydrogel and nanocomposite hydrogel from the Langmuir model was obtained at 45.87 and 58.48 mg/g for crystal violet and 25.51 and 36.36 mg/g for malachite green, respectively. The FTIR analysis before and after dye adsorption showed that electrostatic interaction is the main mechanism of the adsorption process. It can be concluded that synthesized adsorbents have high potential in wastewater treatment applications. [ABSTRACT FROM AUTHOR]

The use of magnetic nanomaterials (MNPs) as adsorbents to eliminate pollution causing dyes from water has attracted substantial attention in recent years because they can be easily isolated and reused. In this work, core–shell Fe3O4@SiO2 MNPs in which magnetic Fe3O4 NPs as a core enclosed with a thick SiO2 shell were successfully synthesized by chemical co–precipitation followed by hydrolysis and condensation of alkoxysilanes in a mixture of ammonia, ethanol and water. The formation of core–shell Fe3O4@SiO2 MNPs has been characterized by TEM, TEM-EDS, XRD, FT-IR and VSM. TEM characterization revealed that several Fe3O4 NPs (around 10 nm) aggregated to form a Fe3O4 magnetic core and surrounded by an uniform SiO2 shell of 40-50 nm thickness to obtain Fe3O4@SiO2 magnetic core–shell NPs. As synthesized core–shell NPs were employed as adsorbent for elimination of two cationic toxic dyes, crystal violet (CV) and malachite green (MG) from aqueous solutions. Further, different adsorption parameters such as pH, adsorbent dosage and contact times of the dyes were found to enhance the adsorption of cationic dyes. At neutral pH 7 the cationic dyes could be speedily removed from aqueous solution with high efficiency. It has been observed that 0.35 g of adsorbent dosage is sufficient for 95% of dye removal efficiency. The contact time is optimised for 20 min for both the dyes. The Langmuir model adsorption isotherm is best suitable which indicates that the cationic dyes adsorption behaviour of Fe3O4@SiO2 is a homogeneous monolayer chemisorption process. The adsorptive binding of CV/MG with Fe3O4@SiO2 was directed through electrostatic interactions. Moreover, the magnetic adsorbents could be easily reused and regenerated with almost no adsorption capability is significantly reduced up to 5 cycles. So, the Fe3O4@SiO2 is an efficient and reusable adsorbent for rapid and removal of cationic dyes from the aqueous solution. [ABSTRACT FROM AUTHOR]

Due to high production costs, the production of activated carbon from waste has attracted a lot of attention recently. In this study, gelidium corneum (GC) was carbonized at 800 °C for 90 min. Its carbonization yield, adsorption capacity, and physical and chemical properties were investigated. Ultraviolet-visible spectroscopy (UV), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), proximate analysis and ultimate analysis were performed. According to XRD analysis, the structure of GC is semi-crystalline, but the crystalline structure increases after carbonization. The carbonization yield of GC was about 39%. According to SEM, UV and XRD analysis, the carbonization process supported crystallinity and the formation of micropore/mesopore structures. The crystal violet (CV) removal and adsorption capacity were 96 % and 9.63 mg/g at an initial dye concentration of 50 mg/L, 30 °C, adsorbent dosage of 5 g/L, constant stirring speed of 200 rpm and equilibration time of 60 min, respectively. The carbonized gelidium corneum (cGC) can be used as a suitable adsorbent for the removal of dyes from aqueous solutions. It can also be an alternative product to commercial products because of its high adsorption capacity and cost-effectiveness.

[Display omitted] • Biowaste cinnamon stick was assessed as a sustainable sorbent. • MIL-125 and CMC were utilized for successfully enhancing CV adsorption. • Equilibrium studies were conducted 3 different temperatures. • q max of CMC/MIL-125@CS was calculated as 6750.58 mg/g. • CMC/MIL-125@CS reached equilibrium the fastest with minimum adsorbent dosage. In the current study, a biowaste cinnamon stick (CS) was used as an adsorbent and modified via in-situ techniques with titanium-based metal organic framework (MIL-125@CS) and carboxymethyl cellulose (CMC/MIL-125@CS). The prepared samples were characterized by various techniques, then utilized for toxic crystal violet (CV) dye removal. CV adsorption was examined for the effects of adsorbent dosage, solution pH, contact time, initial concentration, temperature and anion/cation/natural organic material (NOM). CV removal rate remarkably decreased at low pHs due to the degradation of CV and wavelength shift in the strongly acidic region. The kinetic and isotherm results showed that CMC/MIL-125@CS reached equilibrium much faster (30 min) and much higher adsorption capacity (6750.58 mg/g) than CS and MIL-125@CS. Furthermore, the samples were efficiently regenerated and reusable over five cycles, demonstrating significant adsorption rates. Functional material design approaches yielded superior CV adsorption performance. [ABSTRACT FROM AUTHOR]

Herein, a novel hydrogel (HG-cl-poly(AA)) was synthesized by grafting acrylic acid (AA) onto Hing gum (HG) using methylene-bis-acrylamide (MBA) as a cross-linker and ammonium persulfate (APS) as an initiator in a hot air oven. The percentage swelling of the hydrogel was examined by optimizing various reaction parameters to ensure its maximum swelling percentage. The formation of crosslinked networks was confirmed using Fourier-Transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA) techniques. The surface area and hydrophilicity of the prepared hydrogel were determined using Brunauer–Emmett–Teller analyzer and wettability studies, demonstrating a clear correlation with adsorption. The adsorption of crystal violet (CV) dye on the prepared hydrogel was studied via a batch adsorption system based on the amount of adsorbent, immersion time, pH level, and initial dye concentration. The prepared hydrogel showed a 99% removal rate and an excellent adsorption capacity of 492.61mg/g due to the electrostatic, H-bonding, and dipole–dipole interactions between the adsorbent surface and dye molecules. The results were further analyzed using the Langmuir, Freundlich, and Tempkin isotherm models. The study suggests consistency with the pseudo-second-order kinetic model (R2=0.998), further supported by the best data fit with the Langmuir isotherm model (R2=0.991). The thermodynamic study results indicated that the adsorption process is endothermic and spontaneous. Regeneration (desorption) studies showed that the prepared hydrogel could remove CV dye from an aqueous solution and maintain the highest adsorption capacity even after multiple adsorption and desorption cycles. Therefore, the prepared HG-cl-poly(AA) hydrogel could be a potential adsorbent for dye removal and have an admirable capacity for cleaning the aquatic environment. [ABSTRACT FROM AUTHOR]

Search for water-stable, low-cost materials for sustainable water treatment is on the rise. Recently, phyto-magnetic hybrid materials have been demonstrated as the promising ones, showcasing outstanding water treatment capability, albeit challenging to prepare. Herein, we report the synthesis of peanut shell-embedded magnetic ferrites (MPS) for the scintillating elimination of crystal violet (CV) dye from a series of simulated, spiked, and wastewater. FTIR, FESEM-EDX, VSM, PXRD, and pHZPC elucidate the material characteristics, and CV uptake was mapped concerning various physicochemical parameters like equilibration time (0–90 min), pH (3–11), temperature (298–328 K), ionic strength, and competitive inhibition thwarting from coexistent ions. FTIR suggests the presence of polyphenolic moiety (3428 cm−1) and carbonyl groups (1716 cm−1). FESEM reveals a porous structure with uneven fractures which upon CV uptake converts to a smoother one. Vibrating sample magnetism suggests a typical hysteresis for a soft magnetic material with a saturation magnetization value of 28.464 emu/g and coercivity of 35.240 Oe. The maximum intake capacity is 97.903 mg/g at 298 K, whereas the process follows pseudo-second-order kinetics (R2 = 0.999) and the Langmuir isotherm model (R2 = 0.996). Spontaneity and feasibility of the uptake process were identified from the negative free energy (ΔG = –2.073 kJ/mol), (ΔH = 9.078 kJ/mol), and (ΔS = 0.034 kJ/mol/K). MPS could be revived well using 1:1 MeOH/H2O in up to 91% and elegantly reused for six cycles without significant loss in activity. [ABSTRACT FROM AUTHOR]

This research investigates the synthesis of a hybrid nanomaterial, denoted as Ni‐Zn−S@Cyclodextrine, through a cost‐effective and easy co‐precipitation method. The resulting nanomaterial has been thoroughly characterized and applied for the adsorptive removal of Crystal violet and Congo red dyes from their solutions. The study delves into the thermodynamics and kinetics of the sorption process, as well as helps to propose adsorption mechanism for both the dyes onto the Ni‐Zn−S@Cyclodextrine surface. A comprehensive analysis, encompassing techniques, such as XRD, FTIR, SEM‐EDX, TEM, TGA, Zeta potential, and XPS, have been conducted to explore the structural and morphological attributes of the prepared nanomaterial. Furthermore, key sorption parameters, including adsorbent's dosage, temperature, contact time, and solution pH, have been systematically optimized to achieve maximum efficiency. The TEM images of prepared nanomaterial indicated the particle size ranging between 60–80 nm. Moreover, it exhibited a strong affinity for both the dyes, with a maximum adsorption capacity of 138.20 mgg−1 for Congo red and 129.95 mgg−1 for Crystal violet dyes at 303 K. The thermodynamics of the adsorption process indicated an endothermic and spontaneous nature. Isotherm studies revealed that the data best aligned with the Freundlich isotherm, while the kinetics of the reaction adhered to a pseudo‐second order within the investigated temperature range. [ABSTRACT FROM AUTHOR]

FeS@Fuller's Earth (FeS@FE) was synthesized by borohydride reduction in presence of dithionite with a 10% w/w iron loading. FESEM analysis reveal immobilized FeS NPs (40–100 nm) on the surface of Fuller's Earth with agglomeration. The presence of sulfur as confirmed from XPS and EDX analysis of FeS@FE. Batch adsorption study of FeS@FE for crystal violet (CV) dye adsorption in aqueous solution yielded an optimized adsorption at pH 8, adsorbent dose 0.1 g/L, with a removal of upto 80% of the dye from a 20 mg/L CV solution. The CV adsorption on FeS@FE followed a good non-linear fit for Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm with R2 > 0.95. The maximum monolayer adsorption capacity of FeS@FE was found to be 601.2 mg/g for CV with a D-R Isotherm Free energy of 141.58 kJ/mol at optimum conditions of pH 8, 100 mg/L of CV, and 0.1 g/L of adsorbent dose. The non-linear kinetic fit for CV dye adsorption on FeS@FE fitted to the pseudo-second-order (PSO) and intraparticle diffusion (IPD) models, indicating a strong chemical interaction between CV and FeS@FE. The strong adsorption of CV using FeS@FE is attributed to the Fe-OOH surface formation by FeS immobilized on FE under alkaline conditions, leading to deprotonation and electrostatic adsorption of the dye. [ABSTRACT FROM AUTHOR]

The rapid development of the global production printing and dyeing industry has led to an increase in the demand for various dyes. Crystal violet (CV), a versatile dye, is widely used in the textile industry and other applications. The reason for its widespread use is its effectiveness and the vivid color it gives to fabrics.CV dye is a water-soluble, toxic, resistant organic dye that is quite dangerous for the ecosystem and causes environmental pollution. Therefore, it must be removed before being released into the recipient environment. This study synthesized selenium nanoparticles (Se NPs) from agricultural Prunus avium L. (PaL.) wastes and removed CV dye. In batch adsorption tests, the effects of pH, amount of adsorbent, time, initial concentration, and temperature were investigated. In this study, where 3 different kinetic and isotherm models were tested, it was determined that the most suitable kinetic and isotherm models for the removal of CV dye with PaL-Se NPs were Pseudo second order (R2:0.999) and Langmuir (R2:0.997), respectively. Additionally, the maximum adsorption capacity (qmax) was calculated as 142.61 mgCV/g PaL-Se NP. Accordingly, it can be said that low-cost PaL-Se NPs synthesized by environmentally friendly methods are a suitable alternative for the removal of CV dye. [ABSTRACT FROM AUTHOR]

A nanostructured material, ordered mesoporous carbon (OMC), was synthesised in metal- and halide-free form and its use for the sequestration of crystal violet, a hazardous triphenylmethane dye, is reported for the first time. The OMC material is characterised using scanning transmission electron microscopy with energy-dispersive spectroscopy for chemical analysis, by Fourier-transform infrared spectroscopy, and by nitrogen gas physisorption. The ideal conditions for the uptake of crystal violet dye were determined in batch experiments covering the standard parameters: pH, concentration, contact time, and adsorbent dosage. Experimental data are validated by applying Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin isotherms. The thermodynamic parameters, ΔH°, ΔG°, and ΔS°, are calculated and it has been found that the adsorption process is spontaneous and endothermic with increasing disorder. An in-depth analysis of the kinetics of the adsorption process, order of the reaction and corresponding values of the rate constants was performed. The adsorption of crystal violet over OMC has been found to follow pseudo-second-order kinetics through a film diffusion process at all temperatures studied. Continuous flow column operations were performed using fixed bed adsorption. Parameters including percentage saturation of the OMC bed are evaluated. The exhausted column was regenerated through a desorption process and column efficiency was determined. [ABSTRACT FROM AUTHOR]

With the increase in the use of paint in industrial areas, the rate of dye in wastewater is also increasing. Therefore, the adsorbents used to remove the dye in wastewater are gaining considerable importance. The potential of duckweed (DW) in adsorption of crystal violet (CV), a water-soluble and toxic organic dye, was investigated. Characterization of the adsorbent was made by FTIR, SEM and pHzpc (zero charge point) analyses, and the pHzpc value was 7.75 pH. The effects of temperature, contact time, initial dye concentration, adsorbent dose and solution pH on CV removal were determined. According to the results obtained, the optimum pH, initial dye concentration, adsorbent dose, temperature and contact time were 6 pH, 30 mg L−1, 0.5 g, 30 ºC and 60 min, respectively. The adsorption data were best fitted with Freundlich isotherm (R2 = 0.9714) and maximum adsorption capacity of 61.06 mg g−1 was determined from the Langmuir isotherm. Adsorption of CV by carbonized duckweed (cDW) follows the pseudo-second-order kinetic model (R2 ≥ 0.999). Thermodynamic results of the adsorption process show that adsorption can occur spontaneously (ΔG0 ≤ -5.302 kJ mol−1) and that the process is endothermic (ΔHº = 5.92 kJ mol−1). The results of this study showed that cDWs are cost-effective adsorbent for effective removal of crystal violet dye. [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]

This study investigates the potential of using Ficus religiosa inflorescence (peepal tree) as an efficient solution for removing crystal violet from simulated and industrial wastewater. Various analyses were conducted to understand the adsorbent's structure, including particle morphology, BET surface area, FTIR, and pHZPC. The adsorption process was studied under different physicochemical factors such as temperature, concentration, contact time, and pH. Results revealed rapid adsorption, with 94.15% removal efficiency within the first 15 min at neutral pH. The highest observed adsorption capacity was 198.03 mg g−1, following pseudo-second-order kinetics (R2 = 0.99), indicating chemisorption. The Langmuir model accurately described the adsorption pathway (R2 = 0.99), showing monolayer adsorption. Thermodynamic analysis indicated an exothermic, feasible, and spontaneous process with increased entropy. The adsorbent could be easily regenerated using a 1:1 MeOH/H2O mixture for up to three cycles, yielding up to 73.86%. Real-time application with industrial effluent containing crystal violet showed up to 44.70% adsorption. The experiments demonstrated reliability with evaluated standard deviations (0.017935–0.000577) and relative standard deviations (0.439–0.673%), confirming statistical reliability. In conclusion, it presents a sustainable and eco-friendly approach for removing crystal violet dye from diverse wastewater sources. [ABSTRACT FROM AUTHOR]

The employment of green synthesized nanomaterials for water pollution prevention is increasing nowadays. Herein, Mn-doped ZnO nanoparticles were synthesized using Peganum Harmala seed extract and subsequently used for crystal violet (CV) dye removal from aqueous solutions. The first part of the study describes the preparation of the adsorbent (Mn-ZnO NPs) using a simple coprecipitation method. The surface properties of the material were characterized by Fourier transform infrared spectra (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The second part investigates the adsorption of CV dye onto the surface of the prepared Mn-ZnO NPs. Additionally, the isotherm, kinetics, and thermodynamics of the adsorption process were studied in detail. Batch adsorption analysis was carried out by evaluating different parameters, such as the amount of the adsorbent (0.01g to 0.04 g), CV concentration (20 to 80 mg/L), adsorption time (30 to 120 min), and temperature (35 to 65 ⁰C). The maximum CV dye adsorption capacity of the Mn-ZnO NPs was 45.60 mg/g. The thermodynamic study revealed the spontaneous, exothermic, and feasible nature of the adsorption process, primarily driven by physical forces. Kinetic and isotherm analyses indicated that the adsorption of the dye best fit the Freundlich isotherm and pseudo-second-order models, respectively. Mn-doped ZnO is considered an effective adsorbent for CV, benefiting from its rapid and easy preparation, non-toxic nature, and 94 % adsorption efficiency. The material holds potential for future applications in the removal of organic dyes from wastewater.. [ABSTRACT FROM AUTHOR]

The removal of crystal violet (CV) and methylene blue (MB) from an aqueous solution was successfully accomplished using biochar derived from Moroccan sheep manure (SM). Process optimization revealed adsorption efficiencies of 96.77 % and 98.95 %, with maximum adsorption capacities of 244.08 mg/g and 295.14 mg.g−1 for MB and CV dyes, respectively. This was achieved at pH 11, with an adsorbent dose of 0.5 g.L−1 at 40 μm, over a 120 minutes at 25 °C. The results indicate that the Freundlich isotherm model is the best fit for both dyes. The pseudo-second-order model accurately describes the kinetics of the processes studied for both dyes. The thermodynamic characteristics clearly demonstrated the endothermic and spontaneous nature of the dye elimination. The ΔH° values of 34.3293 and 31.3338 KJ.mol−1for the MB and CV dyes respectively, suggest that physisorption and chemisorption may be involved in the adsorption process. The re-adsorption study revealed that biochar can be reused for up to 5 cycles with both dyes. Adsorption of dyes onto biomass is facilitated by electrostatic, π-π, n-π and hydrogen bonding interactions. Additionally, SMB300 has been identified as an effective, cost-efficient, and environmentally friendly material for removing cationic dyes.

In the present study, Coconut Husk Biochar (CHB) was synthesize from widely available, locally sourced agro waste, coconut husk and characterized using different techniques like scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). CHB was tested for its ability to adsorb crystal violet (CV), a commonly used cationic dye, from water. It was capable of adsorbing more than 98 % of CV from water and follows Freundlich isotherm model with pseudo second order kinetics though the overall process was unfavourable. Moreover, separation of CHB from water after adsorption is a cumbersome process. Thus, unmodified CHB is not suitable for use as an adsorbent for CV. Magnetic nano iron oxide Biochar Composite (MBC) was synthesized by deposition of nano iron oxide (Fe3O4) onto its surface by co-precipitation method and characterized using SEM, XRD and FTIR. SEM analysis provided visual evidence of this deposition which was further confirmed by XRD and FTIR analysis. MBC was also effective in adsorbing more than 90 % of CV from aqueous solution though a decrease in adsorption capacity was observed. Adsorption data followed Langmuir isotherm model and pseudo second order kinetics. MBC is superparamagnetic and is strongly attracted to a small bar magnet, facilitating easy removal from water after CV adsorption.

In this research, activated carbon was obtained from rubber fruit shells (ACRPs). The obtained activated carbon (ACRPs) was modified by magnetite particle coating and silanization with triethoxyiphenylsilane (TEPS) to produce a new magnetic adsorbent (ACRPs-MS). The affinity of as-prepared adsorbent (ACRPs-MS) toward methylene blue (MB) and crystal violet (CV) dyes was tested in mono-component and bi-component solutions. Structural characterization proves the success of the magnetite coating process and the silanization of ACRPs. In the infrared (IR) spectroscopy spectrum of ACRPs-MS, Si–O-Fe and Si–O-Si bonds were identified, which indicated the presence of magnetite and silane. This is also supported by the elemental composition contained in the energy-dispersive X-ray (EDX) diffractogram. In addition, the presence of the porous structure of the surface of the material and the increase in the specific surface area increase the accessibility of contaminants such as MB and CV dyes to be adsorbed to the ACRPs-MS adsorption site effectively. The experimental results showed that the adsorption of mono-component MB and CV dyes by ACRPs-MS was optimum at pH 8 and an interaction time of 60 min. The adsorption kinetics of mono-component MB and CV dyes by ACRPs-MS tended to follow pseudo-second-order kinetics (PSO) models with PSO rate constant (k2) values of 0.198 and 0.993 g mg−1 min−1, respectively. The adsorption of MB and CV dyes by ACRPs-MS in a bi-component mixture tends to follow the Langmuir isotherm model with adsorption capacity (qm) values of 85.060 and 90.504 mg g−1, respectively. Analysis of adsorption data on the bi-component mixture between MB and CV by ACRPs-MS with the Langmuir isotherm equation for a binary mixture resulted in qm of 22.645 × 10–3 mmol equiv g−1. ACRPs-MS material can be used repeatedly five times with adsorption ability > 80%. Desorption of MB and CV dyes was carried out using 0.05 M HCl solution. ACRPs-MS material was able to adsorb MB and CV dyes with a large adsorption capacity and could be used in repeated adsorption. Thus, it can be stated that ACRPs-MS can be used as an effective adsorbent for MB and CV dyes, either singly or in a bi-component mixture. [ABSTRACT FROM AUTHOR]

In this study, the reuse of Citrus fortunella (CF) plant waste, an agricultural product, was evaluated within the scope of sustainability. In this context, selenium nanoparticles (CF‐Se NPs) were synthesized from CF waste extracts and crystal violet (CV) dye was removed. The characteristic structure of the synthesized CF‐Se NPs was determined by X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X‐ray (EDX), Fourier transform infrared spectroscopy (FTIR), UV–vis spectroscopy, and point of zero charge (pHpzc). Batch adsorption tests were applied to determine the effect of the synthesized CF‐Se NPs on CV removal. Four different kinetic and isotherm models were examined using error analysis functions. While the particle size of CF‐Se NPs was determined as 27.58 nm, the pHpzc value was calculated as 9.40, the average surface charge distribution was −24.1 mV, and mass losses were 9.03% and 13.42% at 334.99 and 739.21°C, respectively. The most suitable kinetic and isotherm model for CV removal with CF‐Se NPs was determined to be pseudo‐second‐order with a R2‐value of 0.999 and Freundlich with R2‐value of 0.993, and the qmax was calculated as 23.55 mgCV/gCF‐SeNPs. The effectiveness of CF‐Se NPs synthesized from waste in CV removal is a remarkable issue in terms of sustainable production. [ABSTRACT FROM AUTHOR]

Since caustic dyes are a major component of wastewater used in printing and dyeing, they represent a significant risk to human health. It's getting harder to get rid of them efficiently. An appealing solution to this issue is adsorption based on biomass material aerogel. Here, using the sol-gel process and freeze-drying, an inventive three-dimensional porous aerogel (STA) was created using sodium alginate (SA) and TEMPO-oxidized cellulose (TOC) as raw materials, with the dual cross-linking effects of glutaraldehyde (GA) and Ca2+. Various characterization approaches and analytical methods were used to study STA. The results indicated that the addition of TOC resulted in the excellent pore structure, thermal stability, charge characteristic and adsorption capacity of STA. The adsorption capacity of STA was investigated by selecting crystalline violet (CV) as a typical cationic dye. Thereafter, the adsorption capacity was comprehensively analyzed by varying temperature, pH and adsorption time. The adsorption process conformed to the pseudo-second-order kinetic model, and the Langmuir isothermal adsorption model has a better fit, which was a single-molecule layer chemisorption process. The highest adsorption capacity reached 505.9 mg/g. Moreover, STA also possessed outstanding competitive adsorption capacity and cyclic adsorption performance. Highlights: Sodium alginate and TEMPO-oxidized cellulose were combined innovatively, and the application scope of bio-based materials was expanded. A double cross-linking reaction was achieved in the presence of Ca2+ and glutaraldehyde. The largest porosity reached 95.6% as a result of the three-dimensional porous structure. The maximum adsorption capacity for CV reached 505.98 mg/g. Recycling times and competitive adsorption capacity are excellent. The thermal stability was enhanced to some extent due to the addition of TOC. [ABSTRACT FROM AUTHOR]

Lightweight, metal‐free, sustainable, and reusable adsorbent materials are of paramount significance in addressing the challenges of wastewater treatment. Accordingly, semi‐crystalline nanocellulose (NC) is extracted from tissue paper waste and used to modify polyacrylonitrile (PAN) to produce electrospun nanowebs with strand diameters from ≈180–300 nm. The incorporation of NC into PAN is confirmed by infrared and Raman spectroscopy and X‐Ray diffraction. When tested for crystal violet (CV) adsorption, NC‐modified PAN (20% NC@PAN) exhibits the highest CV removal capacity, achieving 91–94% removal over three cycles each, demonstrating exceptional recyclability. In contrast, unmodified PAN significantly decreases in CV adsorption capacity (from 59% to 48% in the third cycle), possibly due to an increased (≈36%) nanofiber diameter. The adsorption kinetics, exhibiting pseudo‐second order, interparticle (in between nanofibers) diffusion, and Elovich kinetic models emphasize the role of multilayer CV adsorption through reversible chemical interactions. Confocal micro‐Raman spectroscopy unveils a multifaceted CV adsorption mechanism, suggesting both surface and multilayer diffusion, with NC‐enhancing interactions. These findings demonstrate the potential of NC‐modified PAN nanowebs as effective and environmentally sustainable adsorbents for removing CV from aqueous solutions, suggesting promising practical applications. [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]

This study focuses on the development of superparamagnetic and multifunctional Dy doped ZnDyxFe2-xO4 (x = 0.0, 0.01, 0.02, 0.03) ferrite using sol–gel auto-combustion (SG) technique to remove the crystal violet pollutant found in textile industry wastewater using the adsorption and photocatalysis processes. The pure phased spinel cubic crystal structure was achieved for the prepared ferrite nanoparticles, as confirmed through the XRD results. The calculated crystallite size employing the Scherrer formula by taking the high intensity (311) peak was in the range of 26–35 nm. FESEM pictures confirm the presence of spherically shaped grains with definite grain boundaries. With the increasing doping content of Dy, the band gap for the produced photocatalysts was decreased from 1.47 to 1.11 eV. We demonstrated that our prepared Dy doped zinc ferrite nanoparticles behave as a soft magnetic material based on the magnetic measurement data by exhibiting the hysteresis behaviour with low rentivity and coercivity. This indicates the tendency of zinc nanoparticles to exhibit superparamagnetic behaviour at ambient temperature under an external magnetic field. ZnDy0.03Fe1.97O4 (x = 0.03) sample exhibits greater reactivity with a discolouring rate of 92.30% as compared to the ZnFe2O4 degradation rate of 83.07% during 120 min of irradiation under the natural sunlight. Furthermore, the adsorption/photocatalytic activities are amplified as the content of the dopant (Dy) rises, suggesting that the dopants are crucial to the photocatalytic breakdown and the adsorption of crystal violet (CV) dye. Using the antibacterial analysis, it was noted that ZnFe2O4 (x = 0.00) shows the zone of inhibition (ZOI) for both the strains, Bacillus subtilis and Salmonella typhi. With all the excellent magnetic, adsorption, photocatalytic, and antibacterial behaviours, the multifunctional magnetic nanomaterials will be highly beneficial for environmental and biological usages. [ABSTRACT FROM AUTHOR]

The textile industry continues to experience production developments to reach a target for the country's economic development. The increase in production leads to an increase in the amount of waste generated. Dyes such as crystal violet (CV) in textile wastewater are toxic and difficult to remove by conventional treatment. Adsorption with nano adsorbent has been widely researched and developed to remove dyes in the environment because it has various advantages. Magnetic graphene oxide (GO-Fe3O4) as a006E adsorbent has been widely studied because it has a large surface area, strong chemical bonds and is easily separated from the aqueous phase. Puspa (Schima wallichii) wood has the potential to be used as a natural source of graphite. The characterization of the adsorbent was tested with FTIR, SEM-EDS, and BET. The equilibrium time for the adsorption process was 20 min, while the optimum adsorbent dose was 0.04 g. Adsorption isotherm and kinetics analysis showed that CV adsorption using MGO followed Langmuir and pseudo-second-order models, respectively. Thermodynamic studies displayed that the CV adsorption was endothermic and spontaneous. The results of this study suggested that the adsorption of CV using GO-Fe3O4 nano adsorbent from S. wallichii wood proceeds by chemisorption and physisorption.

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 study, Tragopogon dubius was used using a specific condition of adsorption to remove a cationic harmful dye (crystal violet : CV) in aqueous liquid media. Removing time, rate of adsorbent, pH of the media, initial concentration of the harmful dye, and absorbent particle size were studied to reach an optimum adsorption condition. Before and after the biosorption process of CV, the SEM micrographs and EDX spectra were obtained for Tragopogon dubius. The maximum removal efficiency of CV (90–93 %) has happened at pH=7.0, contact time of 120 min, adsorbent dose of 0.2 g/L (with particle size of 0.074 mm), temperature of 25 ○C, and pollutant rate of 50.0 mg/L. The adsorption rate of Tragopogon dubius was calculated using equilibrium models. It was also increased by water washing (30 min). The results showed that 50 % of the dye was absorbed when the adsorption time reached 50 min. Maximum adsorption (212.9 mg/g) occurred after 120 min of removing time. The results revealed the best accordance of the Tragopogon dubius adsorption with the Freundlich model (R2=0.96). A kinetic agreement was also observed between the dye adsorption and the Pseudo‐second order model. The negative value of ΔS° (−53.51 J/K mol) indicates that Tragopogon dubius removes CV during a relatively stable process with randomness in the system. The negative values of ΔG° at different temperatures indicate that the nature of CV adsorption was spontaneous. [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]

In this study, the performance of Rumex acetosella leaves on the adsorptive removal of crystal violet dye from an aqueous solution was investigated. To determine the adsorption conditions, the adsorption studies were carried out under different parameters, namely contact time, temperature (0–120 min), initial pH (2–12), initial dye concentration (10–50 mg/L), and adsorbent dosage (0.2–4 g/L). Four different isotherms were applied, such as Freundlich, Langmuir, Dubinin–Radushkevich, and Harkins–Jura. From the data obtained, it was concluded that the Langmuir model was found to show the best fit for this study. The removal percentage of crystal violet reached a maximum of 94.5% at pH = 7–8 and 25℃. The adsorption capacity reached up to 434.8 mg/g in pH = 7–8 at 25℃. Kinetic studies indicated that adsorption followed the pseudo-second-order kinetic model. BET analysis and intraparticle diffusion data showed that the functional groups on the adsorbent surface were more effective than the surface area and pores in the adsorption process. Thermodynamic parameters were also investigated, and it was observed that the adsorption occurred exothermically and spontaneously. Besides, statistical analyses for isotherm models occurred. [ABSTRACT FROM AUTHOR]

The purpose of this work was to adsorb the triphenylmethane dyes crystal violet (CV), brilliant green (BG), and malachite green (MG) from an aqueous solution using cowdung (CD) that has been gamma‐sterilized. FTIR, SEM, EDX, and TGA‐DTA advanced techniques were used to characterize CD. The material had a pHPZC of 6, and it was shown that the maximal monolayer adsorption capacities for CV (at pH 4.83), BG (at pH 4.53), and MG (at pH 3.75) were, respectively, 179.39, 172.28, and 111.62 mg g−1. The equilibrium results were completely described by the pseudo‐second order model and Langmuir isotherm. Using the van't Hoff and Arrhenius equations, thermodynamic parameters like ΔG, ΔS, and ΔH were computed. The exothermic nature of the process change is indicated by the fact that the adsorption of CV and BG increased with lowering temperature whereas the adsorption of MG increased with increasing temperature, as the process was endothermic. Curiously, the values of the adsorption capacity acquired using the column adsorption approach is very similar to those obtained using batch adsorption trials illustrating the CD's capacity for dyes adsorption. [ABSTRACT FROM AUTHOR]

Crystal violet is a basic dye that is widely used by various industries, such as textiles and paints. These industries discharge their effluents, contaminated with crystal violet, into water streams, and these effluents have an adverse effect on aquatic organisms, the environment, and human health. Crystal violet is a basic dye that is widely used by various industries, such as textiles and paints. These industries discharge their effluents, contaminated with crystal violet, into water streams, and these effluents have an adverse effect on aquatic organisms, the environment, and human health. Hence, this paper is directed at studying the removal of crystal violet using environmentally friendly, cost-effective adsorbent materials such as raw fava bean (RFP-H3F), and chemically activated carbon (H3F) in comparison to commercial activated carbon (CAC).Various characterization techniques are applied, such as XRD, FT-IR,and SEM analyses. Then, the process of optimizing is shown through some preliminary experiments and a Response Surface Methodology (RSM) experiment to find the best conditions for removing crystal violet efficiently. Results revealed that the raw fava bean peels and the commercial activated carbon have the maximum removal efficiency of 95 %, and 83 % respectively, after 180 min of contact time. It is hypothesized that raw fava bean peels (RFP) and chemically activated carbon using phosphoric acid RFP-H3F will exhibit comparable efficiency in removing crystal violet when compared to commercial activated carbon (CAC). Various characterization techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR),and scanning electron microscopy (SEM), are applied to analyze the properties of the adsorbent materials. Afterwards, the optimization process is displayed through some preliminary experiments followed by a Response Surface Methodology (RSM) experiment to obtain the optimum conditions, which achieve high crystal violet removal efficiency. The results demonstrate that both raw fava bean peels and commercial activated carbon exhibit significant removal efficiencies, with raw fava bean peels achieving a maximum removal efficiency of 95 % and commercial activated carbon achieving 83 %.

Lightweight, metal‐free, sustainable, and reusable adsorbent materials are of paramount significance in addressing the challenges of wastewater treatment. Accordingly, semi‐crystalline nanocellulose (NC) is extracted from tissue paper waste and used to modify polyacrylonitrile (PAN) to produce electrospun nanowebs with strand diameters from ≈180–300 nm. The incorporation of NC into PAN is confirmed by infrared and Raman spectroscopy and X‐Ray diffraction. When tested for crystal violet (CV) adsorption, NC‐modified PAN (20% NC@PAN) exhibits the highest CV removal capacity, achieving 91–94% removal over three cycles each, demonstrating exceptional recyclability. In contrast, unmodified PAN significantly decreases in CV adsorption capacity (from 59% to 48% in the third cycle), possibly due to an increased (≈36%) nanofiber diameter. The adsorption kinetics, exhibiting pseudo‐second order, interparticle (in between nanofibers) diffusion, and Elovich kinetic models emphasize the role of multilayer CV adsorption through reversible chemical interactions. Confocal micro‐Raman spectroscopy unveils a multifaceted CV adsorption mechanism, suggesting both surface and multilayer diffusion, with NC‐enhancing interactions. These findings demonstrate the potential of NC‐modified PAN nanowebs as effective and environmentally sustainable adsorbents for removing CV from aqueous solutions, suggesting promising practical applications.

A nanostructured material, ordered mesoporous carbon (OMC), was synthesised in metal- and halide-free form and its use for the sequestration of crystal violet, a hazardous triphenylmethane dye, is reported for the first time. The OMC material is characterised using scanning transmission electron microscopy with energy-dispersive spectroscopy for chemical analysis, by Fourier-transform infrared spectroscopy, and by nitrogen gas physisorption. The ideal conditions for the uptake of crystal violet dye were determined in batch experiments covering the standard parameters: pH, concentration, contact time, and adsorbent dosage. Experimental data are validated by applying Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin isotherms. The thermodynamic parameters, ΔH°, ΔG°, and ΔS°, are calculated and it has been found that the adsorption process is spontaneous and endothermic with increasing disorder. An in-depth analysis of the kinetics of the adsorption process, order of the reaction and corresponding values of the rate constants was performed. The adsorption of crystal violet over OMC has been found to follow pseudo-second-order kinetics through a film diffusion process at all temperatures studied. Continuous flow column operations were performed using fixed bed adsorption. Parameters including percentage saturation of the OMC bed are evaluated. The exhausted column was regenerated through a desorption process and column efficiency was determined.

In the following study, preparation of nano adsorbent from carboxymethyl cellulose (CMC) was carried out by introducing sulfonate group on CMC to prepare sulfonated carboxy methyl cellulose (SCMC). The polymer was used for adsorptive removal of cationic dyes crystal violet (CV) and methylene blue (MB) as models. The produced nanostructure and morphology of the SCMC were investigated by Transmission Electron Microscopic (TEM), Fourier transform infrared (FT-IR) spectroscopic analyses, scanning electron microscopy (SEM), and Zeta potential. Adsorption characteristics of the SCMC for removal of both cationic dye were investigated spectrophotometrically as a function of initial dye concentration and contact time, adsorbent dosage, solution pH, and temperature. The maximum adsorption capacities of the SCMC nanoparticle-based adsorbent for both MB and CV were described by the equilibrium adsorption data of both dyes, which fitted well with the Langmuir model (R2 = 0.998 for MB dye) but for CV the equilibrium data fitted well with Elovich model (R2 =(0.9961). The kinetics of adsorption followed the pseudo-first-order model. The adsorption process is spontaneous and endothermic, according to thermodynamic studies conducted at temperatures ranging from 298 to 313 K. When the parameters are tuned, the adsorbent can remove both dyes quickly and with a high level of efficiency.

Abstract Modification of starch is a potential basic research aiming to improve its water barrier properties. The general purpose of this study is to manufacture cross-linked iodinated starch citrate (ISC) with a degree of substitution (DS) ≈ 0.1 by modifying native corn starch with citric acid in the presence of iodine as an oxidizing agent. Thermoplastic starch (TPS) was generated with urea as a plasticizer and blended with various concentrations of ISC of (2, 4, 6%) (wt/wt) to obtain (UTPS/ISC2, UTPS/ISC4, and UTPS/ISC6). Nanocomposite film was formed from UTPS/ISC2 in presence of stabilized iodinated cellulose nanocrystals UTPS/ISC2/SICNCs via gelatinization at a temperature of 80ºC. Water solubility and water vapor release were studied amongst the water barrier features. The fabricated starch-based composite films were evaluated utilizing Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electronic Microscope analysis (SEM), surface area, and tensile measurements. The adsorption of crystal violet (CV) dye onto produced samples was examined in an aqueous solution. The findings revealed that the UTPS/ISC2/ISCNCs has 83% crystal violet elimination effectiveness. Moreover, the adsorption isotherms were assessed and figured out to vary in the order of Langmuir > Temkin > Freundlich > Dubinin-Radushkevich.

The colored discharges from certain tanning industries into aquatic environments are too heavy with violet crystal; these discharges have recently become a significant environmental problem. The objective of this work is to find an effective method to stop the propagation of these micropollutants in water. Although various treatment techniques have been tested, they are often ineffective in treating these micropollutants. This study focuses on optimizing the parameters involved in the adsorption process of crystal violet (CV) using crude chitin (RC). It was found that a mass of 0.08 g of RC can effectively retain CV. Modeling of the experimental results indicated that the adsorption kinetics of CV onto raw chitin follows pseudo-second-order kinetics at the temperatures studied, and the intra-particle diffusion was not only the rate controlling step. After 80 min of contact, a saturation of the surface is obtained. The Freundlich model describes adsorption isotherms. The adsorbed quantities increase when the pH goes from 4 to 12. The thermodynamic study showed that the adsorption of CV on RC is spontaneous (ΔG° < 0) and endothermic (ΔH° > 0). The value of pHpzc is located at pHpzc = 8.4. Characterization of the raw chitin surface by FTIR, XRD, DTA/TGA and SEM/EDS before and after contact with CV shed light on the nature of interactions between CV and RC.

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]

The present study is focussed on the adsorptive removal of Crystal violet dye from laboratory polluted water using Alysicarpus vaginalis plant material based hybrid multifunctional nanocomposite which was prepared by following co‐precipitation method. The prepared composite MnFe2O4/AV has been characterised using FT‐IR, SEM‐EDX, TEM, XRD, BET, TGA techniques. The nanocomposite has been investigated for its antioxidant activity. The MnFe2O4/AV has been found possessing numerous functional groups on its porous surface and the sorption efficiency was evaluated in terms of parameters, such as sorbent dosage, concentration of the dye, contact time and pH of solution. The maximum adsorption capacity has been obtained as 34.211 mg g−1 and the process was found to be feasible and endothermic in nature. The data fitting showed that the sorption followed pseudo‐second order kinetics. From the sorption data fitting it was found that the sorption followed the Freundlich isotherm. Thus, the MnFe2O4/AV composite proved to be economical to synthesise which is eco‐friendly and has antioxidant ability, thus multifunctional in nature. [ABSTRACT FROM AUTHOR]

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Crystal violet (CV) is the most commonly used cationic dye that is highly carcinogenic in nature. In this study, synthesis of cobalt ferrite and zinc ferrites nanoparticles and grafting of CoFe2O4 and ZnFe2O4 on multi-walled carbon nanotubes (MWCNTs) was carried out by using hydrothermal technique. The prepared nanostructures were characterized by employing various techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy (FES-EM), and energy-dispersive X-ray spectroscopy (EDS). XRD studies confirmed the formation of CoFe2O4 and ZnFe2O4 nanoparticles with average crystallite size of 25 nm and 18.5 nm, respectively. The influence of concentration, pH, and temperature on the adsorption of CV dye was monitored. Batch adsorption experiments were performed to evaluate and optimize the factors that affect the adsorption capacity of nanoadsorbents such as temperature and concentration of dye solution. The removal efficiency of CV for CoFe2O4 and ZnFe2O4 NPs was found 88% and 87%, while it was 96% and 97% for CoFe2O4/MWCNTs and ZnFe2O4/MWCNTs, respectively. The sorption data was fitted to Langmuir, Freundilch and Temkin adsorption isotherms. The thermodynamic parameters like ∆G, ∆H and ∆S have also been calculated. The optimum pH for maximum adsorption of CV onto nanostructures was found out to be 4.5, while with the increase in temperature, an increase in adsorption of dye has been observed which indicates the endothermic nature of the adsorption process. [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]