Kinteics and thermodynamic study of crystal violet on used black tea leaves (original) (raw)
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American Journal of Physical Chemistry, 2021
Ethyl violet (EV) is one of the common pollutants in industrial wastewaters. This study presents the kinetic, isotherm and thermodynamic characterization of the adsorptive removal of EV from aqueous solution by used black tea leaves (UBTL) as a low cost adsorbent. Batch adsorption experiments were performed to investigate the effects of initial dye concentration, solution pH and temperature on the adsorption kinetics. Experimental data were evaluated by inspecting the liner fitness of different kinetic model equations such as pseudo-first order, pseudo-second order, Elovich and Intra-particle diffusion models. The equilibrium amounts adsorbed at different equilibrium concentrations were determined from well fitted pseudo-second order kinetic plot to construct the adsorption isotherm. The maximum adsorption capacity, q m =91.82 mg/g was determined from the well fitted Langmuir plot compared with Freundlich and Temkin plots. Thermodynamic parameters such as free energy change (∆G ads), enthalpy change (∆H ads) and entropy change (∆S ads) of adsorption were determined from adsorption equilibrium constants at different temperatures. The values of thermodynamic parameters revealed that the adsorption of EV on UBTL was feasible, spontaneous and endothermic in nature leading to chemisorption. Again, the equilibrium amount adsorbed, calculated from pseudo-second order kinetic plots for different initial pH of solution was found to be minimum at neutral medium compared with acidic and basic media due to the amphoteric nature of Ethyl violet in aqueous solution and zero point charge of pH of UBTL.
Acta chimica Slovenica, 2010
The low cost adsorbent, spent tea leaves (STL) has been tested for the effectiveness in decolorization of wastewater containing crystal violet dye in batch experiments. Effect of various parameters such as agitation time, pH, temperature and adsorbent dose has been investigated. The dye uptake has been found to increase with pH and temperature. The kinetic uptake data, obtained at different sorbate concentrations, is best interpreted by pseudo second order model and rate constants for adsorption are found to be 8.5 × 10-3, 22.2 × 10-3 and 42.0 × 10-3 g mg-1 min-1 for initial dye concentrations of 10, 20 and 30 mg L-1 respectively. The dye uptake was found to increase with temperature and the activation energy for adsorption process was found to be 10.45 ± 0.89 kJ mol-1.
Adsorption of crystal violet from acidic aqueous solution-
The present study investigates the potential use of used black tea leaves (UBTL) for the removal of Crystal Violet (CV) from acidic solution in batch process. The influences of different adsorption parameters such as contact time, concentration, processing temperatures and ionic strength were investigated. UV-visible spectrophotometer was used to analysis CV at a specific pH (6.0) of solution. Several model isotherms were depicted at different processing temperatures using acidic solution of pH 2.0. Langmuir, Freundlich, Tempkin, Dubinin-Radushkevich (D-R) and Florry-Huggins model equation were subjected to analyze the equilibrium adsorption data. The experimental data reveals Langmuir and D-R models comparatively better fitted than Freundlich, Tempkin and Florry-Huggins models. The equilibrium adsorption capacity (qm) computed from Langmuir equation is 184.1 mg/g at 30 o C which is increased with increase of processing temperature. The adsorption energy (E) calculated from D-R model indicates physical adsorption which plays cardinal role in this adsorption process. The value of separation factor informs that the adsorption process is favorable in nature. The effect of electrolytes (NaCl and NaNO3) suggests a possible adsorption mechanism of CV onto UBTL. The values of thermodynamic variables such as Gibbs free energy (∆Gads), enthalpy (∆Hads) and entropy (∆Sads) suggests the adsorption process is non-spontaneous, physisorption with negligible amount of fragmentation of dye molecules.
Tea dust as a potential low-cost adsorbent for the removal of crystal violet from aqueous solution
Desalination and Water Treatment
The present work demonstrates tea dust (TD) as a potential low-cost adsorbent for the removal of crystal violet (CV) from aqueous solution by batch adsorption technique. Reaction kinetics and isotherm studies were carried out under various conditions of initial dye concentration, contact time, adsorbent dosage, and pH. The adsorbent was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR) and Brunauer–Emmett–Teller. FTIR results showed complexation and ion exchange appeared to be the principle mechanism for CV adsorption. The adsorption isotherm data were fitted to Langmuir and Freundlich equations; and the maximum adsorption capacity was found to be 175.4 mg/g. The removal of CV by TD followed the unified approach model. Therefore, TD can be employed as an efficient and cost-effective adsorbent in industrial wastewater treatment for the removal of basic dyes.
Journal of Water Supply: Research and Technology-Aqua
The present research is based on the removal of Brilliant Green (BG) dye from its aqueous solution. Used-tea-powder (UTP) was used as a potential adsorbent to remove BG from aqueous solution. Pore morphology, surface properties, crystalline nature and thermal stability of UTP were assessed by using SEM, FTIR, XRD and TGA analysis. The optimized working conditions were found to be pH 6, UTP dose 100 mg, adsorption time 60 min and BG concentration 100 mg L−1. The qmax obtained from the Langmuir model was 101.01 mg g−1 showing the utility of UTP in dye removal. The breakthrough volume and efficiency of the column were evaluated through column adsorption studies in fixed-bed mode. It was found that the pseudo-second-order kinetics model was followed as evaluated by the correlation studies. The calculated thermodynamic parameters showed that the adsorption process was feasible, exothermic and spontaneous.
2019
In this paper, adsorptive removal of Crystal Violet dye from aqueous solution using kokum leaf powder was carried out in batch process. The effect of contact time, adsorbent dose, pH, initial concentration and temperature have been studied. The linear regression coefficient R was used to evaluate the best fitting equilibrium isotherm model. Experimental data were best fitted by both Langmuir and Freundlich isotherm models. From the experimental data, it was found that maximum monolayer adsorption capacity of kokum leaf powder was found to be qm = 109.89 mg/g. The pH of solution is an important factor to control the dye adsorption. The adsorption of Crystal violet dye increases with increase in pH and increase in temperatures. The values of RL and thermodynamic analysis indicated that adsorption was spontaneous, endothermic and favorable and increased randomness during adsorption of Crystal violet on Kokum leaf powder. Thus Kokum (Garcinia Indica) leaf powder was found to have effect...
To Chemistry Journal, 2018
Crystal violet (CV), one of the toxic dyes which are extensively used for dyestuffs, textile, paper and plastics industries. CV does not easily biodegrades in aqueous medium and show harmful effect on aquatic as well as human life. In the present work adsorption studies of CV onto husk powder of Red gram crop (Cajanuscajan) seed was examined in aqueous solution at 27.8ºC. The effects of initial concentration, adsorbent dose, temperature, and contact time etc were determined. Highest 81.49% adsorption efficiency recorded was for 50 mg/L solution concentration onto 2.5g of husk powder of Red gram crop seed. The applicability of Langmuir and Freundlich isotherm model was investigated, and the Langmuir adsorption isotherm model exhibited the best fit than Freundlich isotherm model with the experimental data. The adsorption follows pseudo-second-order kinetics.
Adsorption Isotherm of dyes from Aqueous Solutions on Spent tea leaves
Abstract: Adsorption studies for Methylenen blue,Methyl red,Murixed,Birilliant green removal from aqueous solutions on T.L. were carried out. Batch kinetic and isotherm stu dies were carried out under varying experimental conditions at contact time ,initial ions concentration, adsorbent dose and pH .The adsorption data fitted the Langmuir and Freundlich isotherms equations in the whole range of concentrations studied .The ad sorption capacity of compounds was higher (14.22 - 27.26 mg.g - 1 )with the lower values of the temperature (30 - 60Cº),higher values of the initial pH (2 - 14) and agitation rate(180rpm). The effect of temperature and thermodynamic parameters wear also studied , the adsorption amount was increased with decreased the temperature and the reaction was exothermic . The adsorption isotherms data was analyzed using the Freundlich and Langmuir .
Adsorption Science & Technology, 2022
The economic viability of adsorbing crystal violet (CV) using pepper seed spent (PSS) as a biosorbent in an aqueous solution has been studied. A parametrical investigation was conducted considering parameters like initial concentration of dye, time of contact, pH value, and temperature variation. The analysis of experimental data obtained was carried out by evaluating with the isotherms of Freundlich, Sips, Tempkin, Jovanovic, Brouers-Sotolongo, Toth, Vieth-Sladek, Radke-Prausnitz, Langmuir, and Redlich-Peterson. The adsorption kinetics were studied by implementing the Dumwald-Wagner, Weber-Morris, pseudo-first-order, pseudo-second-order, film diffusion, and Avrami models. The experimental value of adsorption capacity (Q m = 129:4 mg g −1) was observed to be quite close to the Jovanovic isotherm adsorption capacity (Q m = 82:24 mg g −1) at (R 2), coefficient of correlation of 0.945. The data validation was found to conform to that of pseudo-second-order and Avrami kinetic models. The adsorption process was specified as a spontaneous and endothermic process owing to the thermodynamic parametrical values of ΔG 0 , ΔH 0 , and ΔS 0. The value of ΔH 0 is an indicator of the process's physical nature. The adsorption of CV to the PSS was authenticated from infrared spectroscopy and scanning electron microscopy images. The interactions of the CV-PSS system have been discussed, and the observations noted suggest PSS as a feasible adsorbent to extract CV from an aqueous solution.