Tea dust as a potential low-cost adsorbent for the removal of crystal violet from aqueous solution (original) (raw)
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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.
International Journal of Innovative Research in Science, Engineering and Technology
In the present investigation, the activated carbon was prepared from tea dust material and utilized for the removal of Basic violet-14 from aqueous solution. The experimental studies were carried out in a batch mode by varying the parameters such as initial dye concentration, adsorbent dose, temperature and pH. The experimental data were analyzed by both kinetic and isotherm models. Pseudo second order kinetics was well fitted than first order kinetics with the rate constants in the range of 1.286X10-4 to 1.653X10-4 gmg-1 min-1. Maximum dye removal was observed at pH=3.05. Thermodynamic parameters calculated for the adsorption of Basic Violet-14 and observed that the adsorption was spontaneous and endothermic with negative G 0 ranges from-1.75 to-5.03 KJ/mol and the positive H 0 value ranges from 20-26 KJ/mol. Hence the prepared TWAC was an alternate to commercial activated carbon and also effective for the removal of BV-14 from aqueous solution.
In the present study, spent tea leaves (STL) were used as a new non-conventional and low-cost adsor-bent for the cationic dye (methylene blue) adsorption in a batch process at 30 • C. Equilibrium sorption isotherms and kinetics were investigated. The experimental data were analyzed by the Langmuir, Fre-undlich and Temkin models of adsorption. The adsorption isotherm data were fitted well to the Langmuir isotherm and the monolayer adsorption capacity was found to be 300.052 mg/g at 30 • C. The kinetic data obtained at different initial concentrations were analyzed using pseudo-first-order, pseudo-second-order and intraparticle diffusion equations. The results revealed that the spent tea leaves, being waste, have the potential to be used as a low-cost adsorbent for the removal of methylene blue from aqueous solutions.
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.
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 .
In the present article, adsorption of anionic dye (Acid Blue 25) using waste tea residue (WTR) was investigated in batch and continuous operation. Clear insight of functional groups, surface charge, morphology, composition, surface area and particle size of WTR was obtained by the characterization techniques of FTIR, zeta potential, SEM-EDX, BET, and DLS analysis. Influence of operating pH, adsorbent loading, influent concentration, contact duration of adsorption and temperature on dye remediation was investigated in batch studies. Evaluated kinetic data was in better agreement with pseudo 2nd order model whereas equilibrium data was in better agreement with Redlich Peterson model. Multiple steps were found to control the mechanism of the studied adsorption. Maximum dye uptake was obtained as 127.14 mg g À1 at optimized pH of 1, loading of 3.5 g L À1 and higher temperature as 318 K. Adsorption process was found to be spontaneous, physical and favored with the rise in temperature. Reusability of WTR in multiple cycles showed a slight drop in dye uptake from 27.95 ± 0.26 mg g À1 at 1st cycle to 26.24 ± 0.21 mg g À1 at 3rd cycle. Continuous studied were also conducted in packed column and influence of column operating parameters as packing height (3e6 cm), concentration (50e200 mg L À1) and the flow rate of influent (5e9 mL min À1) on the efficacy of dye remediation were investigated. Thomas model was reported to be in better agreement with the evaluated breakthrough data. Maximum uptake in continuous studies was reported as 50.82 mg g À1. The obtained results of batch and continuous studies depicted that WTR could be used effectively for remediation of targeted anionic dye from the aqueous phase.
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.
Adsorption of Crystal Violet dye by using a low-cost adsorbent – peanut husk
DESALINATION AND WATER TREATMENT
Nowadays, industrial effluent containing textile dyes is considered a major environmental concern. Crystal violet (CV) is one of the vital textile dyes of the triphenylmethane group and it is known for its mutagenic and mitotic poisoning nature so it must be treated. This study aims to evaluate the adsorption potential of peanut husk (PH) towards CV dye removal. Adsorption studies are conducted to study the effects of different parameters on adsorption such as particle size of adsorbent (105, 210, and 500 mesh sizes), initial dye concentration (5-100 mg/L), contact time (5-120 min), pH (1-11), temperature (0-60°C), and adsorbent dosage (0.1-1.0 g). Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models are applied to experimental data for the determination of the nature of adsorption. The kinetic studies have been carried out using the pseudo-first-order, pseudo-second-order, and intra-particle diffusion model for adsorption of CV on PH. Thermodynamic parameters such as changes in Gibb's free energy (∆G), enthalpy (∆H), and entropy (∆S) are also determined. Optimum conditions for maximum removal of toxic CV dye from wastewater on PH includes 210 mesh size, 100 ppm initial dye concentration with 10 min contact time at temperature 30°C using 0.1 g of adsorbent. Alkaline medium favors adsorption of CV onto the surface of PH and its maximum removal is observed at a pH of 8. These optimum conditions result in 90% removal of CV dye from aqueous solution and the maximum adsorption capacity found out was 20.95 mg/g. Applicability of this developed procedure with tap water is 83.16% indicating that the PH is a promising adsorbent for the removal of cationic CV dye from the aqueous solution.
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.
International Journal of Integrated Engineering, 2022
Water contamination is one of the significant issues faced by many countries in the world. Many organic and inorganic pollutant had been found in aquatic ecosystem due to waste disposal of various elements from agriculture, industry and mining [1], [2]. Synthetic dye is one of most concern pollutants since its increasing in usage for industrial purposes lead to its high abundance in the water environment. These included due to the rapid development of rubber, textile, paper, plastic, leather and food technology. The high amount of water usage for dying process have resulted in expendables mixture of natural and synthetic dyes, e.g., nitro, azo, methane and carbonyl that resistant to the biodegradation. In addition, the adverse health effect resulted by the utilization of dyes might be arise due to its carcinogenic properties [2]. Moreover, the aquatic organisms that require oxygen and sunlight for living will be suffocated because high color and COD content in the water. The water contaminated with dye requires an effective and an efficient treatment to dismiss the environmental threat. Up to now, various methods and approaches successfully eliminated the dye molecules, including ion-exchange, coagulation-flocculation, electrochemical, ozonation and adsorption. Amongst, adsorption was mostly chosen since it displayed high removal capability [3]. Adsorption uses adsorbent materials, composed of activated carbon which is expensive and limit to certain dye. Therefore, the need of novel adsorbent as alternative is highly demanded. Many researches on adsorption have demonstrated the removing process of dye [4]-[6] generate three by product such as activated carbon, carbonaceous adsorbents and polymeric adsorbents. Overall, activated carbon was widely used [7],