Adsorption Of Crystal Violet Dye Research Articles

Constructing the synergistic effects of chitosan and ionic liquid on SPEEK polymer for efficient adsorption of crystal violet dye

In the study, a novel chitosan biopolymer and 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid (IL)-incorporated sulfonated poly (ether ether ketone) (SPEEK) composite (Ch-IL@SPEEK) was prepared for adsorption of cationic crystal violet (CV) dye. The proposed composite was well characterized by several techniques. CV adsorption performance was examined via batch studies by varying various variables involving adsorbent dosage, contact time pH and temperature. The isotherm results were demonstrated the adsorption characters of the processes were Langmuirian. The maximum adsorption capacity was determined as 77.66 mg g−1 for the composite which was significantly higher than SPEEK (qmax = 45.36 mg g−1). The determined equilibrium time of the operated system was 360 min and the kinetic model was assessed as Elovich. At low pHs the protonated surface groups repelled the positively charged CV and the adsorption rate increased with increasing pH. The process is spontaneous and favorable as it proceeds via endothermic interactions. Furthermore, even at the end of 5 successful adsorption cycles, 77.86 % CV removal was obtained. Remarkable efficiencies were also achieved in the removal performance of different organic pollutants. Based on the reported results, Ch-IL@SPEEK composite were exhibited as an impressive adsorbent material for adsorption processes.

Desirability function and Box-Behnken design optimization for crystal violet dye adsorption by palm date stone activated carbon

Desirability function and Box-Behnken design optimization for crystal violet dye adsorption by palm date stone activated carbon

Adsorption of crystal violet dye from synthetic wastewater by ball-milled royal palm leaf sheath

The current study shows that using a batch approach to remove crystal violet dye from synthetic wastewater is feasible when using royal palm leaf sheath powder as an adsorbent. In order to investigate the effects of many parameters, including starting concentration, pH effect, dye concentration, adsorbent dose, contact time, and temperature, experiments were carried out under various operating conditions. Maximum removal was obtained at pH 6 and at a concentration of 100 ppm, which are considered as ideal values. The influence of pH and dye concentration was shown to be substantial. Langmuir, Freundlich, and Temkin isotherm models were fitted to equilibrium data. The Langmuir isotherm model, which showed a maximum monolayer adsorption capacity of 454.5455 mg/g, best described the equilibrium data. The Pseudo-second-order kinetic model was found to closely resemble rather than the first-order and intra-particle diffusion models. Standard enthalpy (∆H◦), entropy (∆S◦), and free energy (∆G◦) were evaluated as thermodynamic parameters. It was discovered that the adsorption contact was endothermic in nature. The outcomes highlight the applicability of the inexpensive, locally accessible adsorbent in the specialty area of wastewater treatment and can be used in commercial dye-enriched effluent.

Synthesis, characterization and analysis of conducting polymer composites toward dye adsorption

The present effort reports on the synthesis of novel and recyclable polymer-based adsorbents based on polypyrrole (PPy) and polyethyleneimine (PEI) for the removal of cationic crystal violet (CV) dye from aqueous solutions. The characterization of the composites was determined by FTIR, XRD, FESEM, and XPS techniques. The effects of different variables on the adsorption of crystal violet dye were studied, including the pH, adsorbent doses, and contact time. The research findings show that the different oxidants used to prepare polypyrrole in PPy-PEI adsorbents play a vital role in CV dye adsorption. The PPy-PEI composite prepared by using the ammonium persulfate oxidant was found to exhibit the highest adsorption of 70.9% among the three different oxidants, namely, anhydrous ferric chloride, ferric chloride hexahydrate, and ammonium persulfate. The ideal adsorption conditions for the removal of CV dye were discovered using an adsorbent dosage of 0.3 g at pH 11, with a contact time of 180 min. Kinetic regression analysis indicated that the adsorption processes followed the pseudo-second order kinetic model and fit well with the Langmuir isotherm, with a maximum monolayer sorption capacity of 142.86 mg/g at a temperature of 27 °C. In addition, the regeneration of the PPy-PEI composite was accomplished with dye adsorption efficiency decreasing from 70.9% to 64.4% after three adsorption-desorption cycles. The present work suggests that the PPy-PEI composite is a promising adsorbent for removing cationic CV dye in aqueous solutions.

Removal of Crystal Violet Dye in Textile Wastewater Using Rice Husk Biochar


 
 
 Crystal Violet Dye (CVD) is a water-soluble, hazardous organic dye that causes adverse health issues and environmental pollution. This dye was mostly added to wastewater by the textile industries. Treatment of CVD-contained wastewater has become a great challenge due to high investment and operating costs and inefficiency in dye removal of conventional methods such as biological degradation and chemical oxidation. So, the main purpose of this study is to investigate the CVD removal ability of Rice Husk Biochar (RHB). The experiment procedure was designed to determine the influence of initial CVD concentration, adsorbent dosage, pH, contact time, and temperature on dye removal. RHB was prepared by pyrolysis process at 700o C for 3h at a constant heating rate of 10o C min-1 in a muffle furnace. Adsorption of CVD by RHB was verified by performing Fourier Transform Infrared spectroscopy. The concentration of the remaining dye after adsorption studies was calculated using Ultra-Violet visible spectroscopy. According to the results, the dye removal efficiency increased with the RHB amount, but the rate of this increment decreased at higher RHB dosages. The highest dye removal efficiency of 97.33% was recorded at 1.5 g RHB amount. In the effect of initial CVD concentration, the efficiency increased up to 600 mg/l and then decreased and the maximum removal efficiency was 96.77%. pH value has no significant effect on dye removal and the highest efficiency of 97.3 % was recorded at pH 4. Further, as the contact time increased, the dye removal increased until it reached an equilibrium state at 60 minutes with 92.03% efficiency. Moreover, when raising the temperature, the adsorption of CVD by RHB marginally increased. According to the kinetic studies, the experimental data followed pseudo- second-order kinetic models than pseudo-first order. Further, adsorption equilibrium data well fitted both Freundlich and Langmuir isotherm models so that it can be assumed that both monolayer and multilayer adsorption of CVD in RHB surface. Thermodynamic parameters such as Gibbs free energy and enthalpy change were calculated, and all values were recorded as negative implying adsorption was favorable and spontaneous and the process was exothermic. In conclusion, the optimum dye removal was recorded at 350 C and pH 4 with an initial dye concentration of 600 mg/L and adsorbent dosage of 1.5 g. Thus, this study concluded that RHB could be utilized as a cost- effective, eco-friendly, and affordable adsorbent for the removal of CVD from wastewater with over 90% dye removal efficiency.
 Keywords: Crystal violet dye, Rice husk biochar, Textile industry, Adsorption
 
 

Retracted: Adsorption of Crystal Violet Dye from Aqueous Solution using Industrial Pepper Seed Spent: Equilibrium, Thermodynamic, and Kinetic Studies

Retracted: Adsorption of Crystal Violet Dye from Aqueous Solution using Industrial Pepper Seed Spent: Equilibrium, Thermodynamic, and Kinetic Studies

Novel insights into crystal violet dye adsorption onto various macroalgae: Comparative study, recyclability and overview of chromium (VI) removal

In this study, effective biomaterials were prepared from marine macroalgae, namely Fucus spiralis (F.S), Ulva intestinalis (U.I), and Corallina officinalis (C.O). The ability to adsorb the hazardous organic dye crystal violet (CV) was examined, revealing different adsorptive properties for the three algae. The removal of CV dye occurred onto only a homogeneous monolayer for F.S, and both a homogeneous monolayer and a heterogeneous multilayer for U.I and C.O algae. The predicted monolayer capacities at 25 °C were approximately 53 mg/g, 55 mg/g, and 97 mg/g for F.S, C.O, and U.I, respectively. The adsorption of CV dye on all the algae was found to follow a pseudo-second-order rate. Ulva intestinalis algae, as a potential adsorbent of CV dye, were also tested in the adsorption of inorganic substances and demonstrated significant efficiency in the removal of chromium (VI). The findings highlight various adsorption properties and the relevance of macroalgae for wastewater treatment applications.

Harnessing the potential of modified cellulosic pumpkin seed hulls as affordable biosorbents for cationic dye removal from aqueous solutions: adsorption kinetics and isotherm studies

AbstractThis investigation focuses on examining the adsorption behavior of crystal violet dye on cellulose (CS) and its modified forms, including cellulose loaded with nicotinic acid (CSN) and cellulose loaded with thiourea (CST). Batch experiments were performed to analyze the adsorption process, while various characterization techniques, such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA), were utilized to assess the structural and morphological changes in the cellulose materials. The findings reveal that the adsorption process follows a pseudo-second-order kinetic model, indicating a chemical adsorption mechanism. Additionally, the Langmuir isotherm model suggests monolayer adsorption on cellulose surfaces. Thermodynamic analysis demonstrates that the adsorption process is spontaneous and exothermic for CS and CSN, whereas it is endothermic for CST. The characterization techniques employed provide valuable insights into the structural modifications and porous properties of cellulose materials. Overall, this study underscores the potential of modified cellulose materials to effectively remove dyes in wastewater treatment applications. Notably, thiourea-loaded cellulose CST exhibits superior adsorption capacity with removal percentages of 78.2% compared to CS and CSN, whose removal percentages were 76.45% and 76.72%, respectively, suggesting the promising role of CST in dye removal. These findings contribute to a comprehensive understanding of crystal violet dye adsorption on cellulose and its modified forms, thereby paving the way for future research on the application of modified cellulose materials in wastewater treatment processes.

Adsorption of Crystal Violet Dye by Biochar produced from Sugarcane Bagasse under Different Temperatures

Adsorption of Crystal Violet Dye by Biochar produced from Sugarcane Bagasse under Different Temperatures

Study on the Isotherms, Kinetics, and Thermodynamics of Adsorption of Crystal Violet Dye Using Ag-NPs-Loaded Cellulose Derived from Peanut-Husk Agro-Waste.

A huge amount of textile dyes are released as industrial waste into the environment each year, which alters the water's natural appearance and causes toxicity and carcinogenicity in the human body. Peanut husk is considered an agro-waste and contains many valuable compounds, such as cellulose. Different concentrations of cellulose were extracted from peanut husk and then loaded with bio-silver nanoparticles, which were fabricated using neem leaves (Azadirachta indica) as a reducing agent to form Ag-cellulose nanocomposites (Ag-Cell-NCMs). Different devices were used to characterize Ag-Cell-NCMs. The TEM images displayed that the size of Ag-Cell-NCMs ranged between 13.4 and 17.4 nm after dye adsorption. The Ag-Cell-NCMs were used to adsorb toxic dyes such as crystal violet (CV). Different parameters were applied, such as the ratio of cellulose to Ag-NPs, pH, contact time, adsorbent dose, dye concentration, and the temperature required to reach the optimization conditions to remove CV dye from the aqueous solution. Different kinetics and isotherm models were applied to the experimental data to explain the mechanism of the adsorption process. The adsorption of CV on Ag-Cell-NCMs follows the pseudo-second order, and the best-fit isotherm was the Langmuir isotherm. The new composite was tested for the possibility of dye desorption and ability to be reused several times, and we found that the new nanocomposite can be reused for multiple adsorptions and there is a possibility of dye desorption.

Experimental and Computational Studies of Nitric Acid Treated Natural Sargassum Algae for Efficient Removal of Crystal-Violet Dye

In this work, crystal-violet (CV) dye was removed using a chemical carbonization process to create carbonized sargassum algae (CSA), which poses less environmental danger. The produced CSA is examined using a scanning electron microscope and a Fourier-Transform Infrared spectrometer. The following parameters were measured: pH, contact duration, temperature, adsorbent concentration, and starting CV dye concentration. The highest removal % was recorded as 91.17%. at pH 7, 3 hours, 25 °C, 0.01 g of adsorbent dosage, and 100 mg/L initial dye concentration. The kinetic testing indicated that pseudo-second-order was the most effective kinetic model for CV adsorption. According to the isotherms for the adsorption of CV dye, the Langmuir constant (K) was used to measure thermodynamic properties like free enthalpy (H), entropy (S), and energy (G). The Freundlich model, followed by Temkin models, best described the data. The earlier research is supported by computational studies like molecular dynamics (MD) simulation and Monte Carlo (MC) simulation.

Poly (Vinyl Alcohol) Hydrogels Boosted with Cross-Linked Chitosan and Silver Nanoparticles for Efficient Adsorption of Congo Red and Crystal Violet Dyes.

In our previous work, three different weight ratios of chitosan/PVA (1:3, 1:1, and 3:1) were blended and then cross-linked with trimellitic anhydride isothiocyanate (TAI) at a concentration depending on their chitosan content, obtaining three hydrogels symbolized by H13, H11, and H31. Pure chitosan was cross-linked with TAI, producing a hydrogel symbolized by H10. Further, three H31-based silver nanoparticles composites (H31/AgNPs1%, H31/AgNPs3%, and H31/AgNPs5%) were also synthesized. They were investigated, for the first time in this study, as adsorbents for Congo Red (CR) and Crystal Violet (CV) dyes. The removal efficiency of CR dye increased with increasing H10 content in the hydrogels, and with increasing AgNP content in the composites, reaching 99.91% for H31/AgNPs5%. For CV dye, the removal efficiency increased with the increase in the PVA content. Furthermore, the removal efficiency of CV dye increased with an increasing AgNP content, reaching 94.7% for H31/AgNPs5%. The adsorption capacity increased with the increase in both the initial dye concentration and temperature, while with an increasing pH it increased in the case of CV dye and decreased in the case of CR dye. The adsorption of CV dye demonstrated that the Freundlich isotherm model is better suited for the experimental results. Moreover, the results were best fitted with pseudo-second-order kinetic model.

Removal of crystal violet dye from wastewater using low-cost biosorbent Trifolium repens stem powder

Crystal violet (CV) synthetic dyes are well known in the dyeing industry for their mitotic and mutagenic poisoning. CV dye being a toxic organic dye is responsible for serious health issues as well as environmental damage. In this study, an inexpensive biosorbent (white clover: Trifolium repens) stem powder was tested for the adsorption of CV dye (cationic dye) from an aqueous solution. The batch adsorption measurements were designed to find out the influence of contact time, pH, adsorbent dose, and dye concentration, for dye removal. The operation parameters studied are the contact time (20 to 160 min), initial dye concentration (10–100 mg/L), dose (0.1–1 g), and pH, (1–10). At optimum conditions, maximum percent removal of 92.997% and adsorption capacity value of 1.952 mg/g was achieved at pH 2, adsorbent dose (1 g), and contact time (140 min), and dye concentration (70 ppm). The results suggested that the removal of CV rose with the contact time and adsorbent dose. Langmuir and Freundlich isotherm models were applied to the equilibrium adsorption data, and data were perfectly fitted to Langmuir isotherm model. Pseudo-first-order and pseudo-second-orders were applied to the data, and it was found that the pseudo-second-order kinetic model was best fitted to the experimental data. It was also revealed that the stem powdered of the Trifolium repens plant can be employed as a useful adsorbent to remove cationic CV dye from different water samples (tap, river and distilled). Furthermore, the performance of adsorbent was also evaluated in saline water containing sodium chloride, potassium chloride and manganese chloride salts to check the effect of various ions on the performance of adsorbent and it was observed that the adsorbent showed excellent performance in saline water. Moreover, a comparative study was performed to check the efficiency of different commercial adsorbents (silica gel and active carbon) and to compare their performance with our study. All these experiments revealed that the biosorbent used in this study effectively removes contaminating dyes from industrial wastewater and as well as saline water and thus, can be used for the treatment of wastewater at the commercial level.

Okra-psyllium based green synthesis of eco-friendly bio-adsorbent for efficient removal of uranium and crystal violet dye from aqueous media: statistical optimization using response surface methodology

Abstract The prime objective of this study is to synthesize eco-friendly okra-psyllium based hydrogel through free radical crosslinking method by using citric acid-ammonium persulfate as a crosslinker-initiator system. Various techniques were used to explore the morphology, structure and thermal behaviour of the synthesized hydrogel via. Powdered X-ray diffraction studies, SEM and TGA techniques. Response surface methodology was performed to maximize the grafting percentage of the synthesized hydrogel up to 244 % and swelling percentage of 598 %. The physicochemical properties like salt-resistance behaviour and the impact of ionic strength on the swelling percentage of synthesized hydrogel were investigated and thus observed with the following trend as K+ > Ca2+ > Fe3+. Furthermore, the synthesized sample showed an excellent bio-adsorbent behaviour for the removal of uranium with 97.75 % removal in 60 min and crystal violet dye removal up to 85.32 % in 24 h from contaminated water. Various kinetic and isotherm adsorption modelling were implied to probe the mechanism of adsorption with displayed interactions between the absorbate and the absorbent. The Langmuir isotherm model was well-fitted in dye adsorption case with regression co-efficient value of 0.99. In case of uranium, tempkin isotherm model was best fitted with regression co-efficient value as 0.92. Crystal violet dye adsorption favoured second-order kinetic model whereas the adsorption mechanism of uranium followed first-order kinetics. Hence, the revealed results depicted that the synthesized hydrogel served as a potential candidate for the effective removal of toxic dye (crystal violet) and metal ion (uranium) from aqueous media with a sustainable approach towards environment.

A Novel High-Efficiency Natural Biosorbent Material Obtained from Sour Cherry (Prunus cerasus) Leaf Biomass for Cationic Dyes Adsorption.

The present study aimed to investigate the potential of a new lignocellulosic biosorbent material derived from mature leaves of sour cherry (Prunus cerasus L.) for removing methylene blue and crystal violet dyes from aqueous solutions. The material was first characterized using several specific techniques (SEM, FTIR, color analysis). Then, the adsorption process mechanism was investigated through studies related to adsorption equilibrium, kinetics, and thermodynamics. A desorption study was also performed. Results showed that the Sips isotherm provided the best fit for the adsorption process of both dyes, with a maximum adsorption capacity of 168.6 (mg g-1) for methylene blue and 524.1 (mg g-1) for crystal violet, outperforming the capacity of other similar adsorbents. The contact time needed to reach equilibrium was 40 min for both studied dyes. The Elovich equation is the most suitable model for describing the adsorption of methylene blue, while the general order model is better suited for the adsorption of crystal violet dye. Thermodynamic analyses revealed the adsorption process to be spontaneous, favorable, and exothermic, with physical adsorption involved as the primary mechanism. The obtained results suggest that sour cherry leaves powder can be a highly efficient, eco-friendly, and cost-effective adsorbent for removing methylene blue and crystal violet dyes from aqueous solutions.

Modeling and Optimizing the Crystal Violet Dye Adsorption on Kaolinite Mixed with Cellulose Waste Red Bean Peels: Insights into the Kinetic, Isothermal, Thermodynamic, and Mechanistic Study.

In this study, a new eco-friendly kaolinite-cellulose (Kaol/Cel) composite was prepared from waste red bean peels (Phaseolus vulgaris) as a source of cellulose to serve as a promising and effective adsorbent for the removal of crystal violet (CV) dye from aqueous solutions. Its characteristics were investigated through the use of X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and zero-point of charge (pHpzc). The Box-Behnken design was used to improve CV adsorption on the composite by testing its primary affecting factors: loading Cel into the composite matrix of Kaol (A: 0-50%), adsorbent dosage (B: 0.02-0.05 g), pH (C: 4-10), temperature (D: 30-60 °C), and duration (E: 5-60 min). The significant interactions with the greatest CV elimination efficiency (99.86%) are as follows: BC (adsorbent dose vs. pH) and BD (adsorbent dose vs. temperature) at optimum parameters (A: 25%, B: 0.05 g, C: 10, D: 45 °C, and E: 17.5 min) for which the CV's best adsorption capacity (294.12 mg/g) was recorded. The Freundlich and pseudo-second-order kinetic models were the best isotherm and kinetic models fitting our results. Furthermore, the study investigated the mechanisms responsible for eliminating CV by utilizing Kaol/Cel-25. It detected multiple types of associations, including electrostatic, n-π, dipole-dipole, hydrogen bonding interactions, and Yoshida hydrogen bonding. These findings suggest that Kaol/Cel could be a promising starting material for developing a highly efficient adsorbent that can remove cationic dyes from aqueous environments.

Synthesis of a novel magnetically recyclable starch-based adsorbent for efficient adsorption of crystal violet dye

A novel magnetic starch-based adsorbent (MSBA) was synthesized from the copolymer solution of starch-grafted acrylic acid treated by an alkali homogeneous phase as the precursor and Fe3O4@SiO2 particles as raw materials. The feasibility of dye wastewater treatment was studied using crystal violet (CV) cationic dye as the model dye. The research results have indicated when the optimum condition kept the temperature of 308 K, CV concentration of 10 mg·L-1, pH of 9.0, the adsorbent dosage of 0.10 g, and the adsorption time of 50 min, 90.31% of the CV can be removed by the MSBA. In terms of the Langmuir isotherm model, the maximum adsorption capacity for CV was 49.10 mg·g−1. The magnetic saturation intensities of MSBA were 14.80 emu·g−1. The kinetics results showed that the adsorption process conformed to the first-order model and the rate-controlling step was determined by multiple stages. In addition, the adsorption isotherms displayed that CV adsorption was well fitted to the Langmuir model, and thermodynamic parameters depicted the spontaneous endothermic process. The adsorption mechanism of CV involved electrostatic interaction and hydrogen bonding. The adsorbents can be regenerated in ethanol solution and the removal efficiency remained at 83.04% even after five adsorption-desorption cycles. MSBA can be recovered with a magnet and only experience a 7.6% loss of adsorbent with each reuse cycle. These results suggest MSBA is a promising candidate adsorbent for dye wastewater treatment because of its excellent properties, including high adsorption efficiency, simple magnetic separation and reusability.

Textural properties and adsorption behavior of Zn–Mg–Al layered double hydroxide upon crystal violet dye removal as a low cost, effective, and recyclable adsorbent

The preparation of adsorbents plays a vital role in the adsorption method. In particular, many adsorbents with high specific surface areas and unique shapes are essential for the adsorption strategy. A Zn–Mg–Al/layer double hydroxide (LDH) was designed in this study using a simple co-precipitation process. Adsorbent based on Zn–Mg–Al/LDH was used to remove crystal violet (CV) from the wastewater. The impacts of the initial dye concentration, pH, and temperature on CV adsorption performance were systematically examined. The adsorbents were analyzed both before and after adsorption using FTIR, XRD, and SEM. The roughness parameters and surface morphologies of the produced LDH were estimated using 3D SEM images. Under the best conditions (dose of adsorbent = 0.07 g and pH = 9), the maximum adsorption capacity has been achieved. Adsorption kinetics studies revealed that the reaction that led to the adsorption of CV dye onto Zn–Mg–Al/LDH was a pseudo-second-order model. Additionally, intraparticle diffusion suggests that Zn–Mg–Al/LDH has a fast diffusion constant for CV molecules (0.251 mg/(g min1/2)). Furthermore, as predicted by the Langmuir model, the maximal Zn–Mg–Al/LDH adsorption capacity of CV was 64.80 mg/g. The CV dimensionless separation factor (RL) onto Zn–Mg–Al/LDH was 0.769, indicating that adsorption was favorable. The effect of temperature was performed at 25, 35, and 45 °C in order to establish the thermodynamic parameters ∆Ho, ∆So, and ∆Go. The computed values indicated exothermic and spontaneous adsorption processes. The study presented here might be used to develop new adsorbents with enhanced adsorption capabilities for the purpose of protecting the water environment.

Efficient adsorption of crystal violet (CV) dye onto benign chitosan-modified l-cysteine/bentonite (CS-Cys/Bent) bionanocomposite: Synthesis, characterization and experimental studies

Crystal violet (CV) a cationic dye is more harmful than anionic dye. CV is employed in many industries, including leather, paper, pharmaceutical, textile, and cosmetics. It causes several harmful effects like eye and skin irritation; in extreme situations, it causes renal and kidney or respiratory failure. Because it is non-biodegradable, this dye sticks to the aquatic environment for a very long period. Therefore, it is important to remove this dye from wastewater to prevent its contamination to normal water bodies. This study evaluated the performance of Chitosan-modified l-cysteine/Bentonite (CS-Cys/Bent) bionanocomposite for the adsorption of CV dye. To investigate the surface morphology and potential interaction between the (CS-Cys/Bent) bionanocomposite and CV dye, the (CS-Cys/Bent) were characterized by TEM, SEM-EDX, FTIR and XRD techniques. At pH-8, with 0.01 g of adsorbent dosage, and an optimal duration of 180 min, the maximum adsorption capacity (85.13 mg/g) was observed. The maximum adsorption capacity was 219, 237, and 240 mg/g at 303, 313 and 323 K. The experimental data were subsequently examined using a variety of isotherm models; with the highest R2 values (0.990, 0.983 and 0.984 at 303, 313 and 323 K, respectively), the Freundlich model was the best fitted model. Among the kinetics models, pseudo-second order (PSO) was the best-described kinetic model with the highest coefficient (R2, 0.999). The positive values of ΔS° (0.037 kJ/mol.K) and ΔH° (7.148 kJ/mol) demonstrated the process to be spontaneous and endothermic. The (CS-Cys/Bent) can be successfully recycled up to the fourth cycle.

Adsorption of crystal violet dye from wastewater on Phyllanthus emblica fruit (PEF) powder: kinetic and thermodynamic

ABSTRACT This research focused on removal of cationic crystal violet dye using Phyllanthus emblica fruit (PEF) powder (as an adsorbent) from wastewater. Operational parameters such as solution pH, adsorbent dose, contact time, dye concentration, as well as temperature were optimised. Results showed that maximum amount of dye, i.e. 84%, has been adsorbed at optimised condition employing particles of mesh sizes 510 µm, at 12 pH, adsorbent dose of 0.4 g, with contact time of 30 min, having dye concentration of 20 ppm at 20°C temperature. Characterisation of adsorbent was done by FTIR and SEM techniques which confirmed the involvement of carboxylic as well as hydroxyl functional groups in dye adsorption, and heterogeneous, highly porous surface (which were occupied after dye adsorption) of adsorbent which favours dye adsorption. Concentration and contact time data of study was applied to various isotherms and kinetic models respectively and investigation of the best fitted model of was carried out. It was found that Freundlich isotherm model (with = 0.986) and pseudo-second-order kinetic model (with = 0.986) was best fitted to experimental data. Thermodynamic study revealed value of ΔG varied from −29.495 to-33.610 kand ΔH was 6.175 k confirming that the process was spontaneous and endothermic in nature. Applicability of current procedure with tap water showed 74% results, and regeneration showed that nearly 79% of dye was desorbed, indicating the effectiveness of Phyllanthus emblica fruit (PEF) powder for adsorptive removal of crystal violet dye from wastewater.