Adsorption of Crystal Violet dye by using a low-cost adsorbent – peanut husk (original) (raw)
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REVIEW PAPER ON REMOVAL OF A DYE FROM AQUEOUS SOLUTION BY ADSORPTION
To investigate the adsorption capacities of locally available low cost bio-adsorbents like neem leaves, orange peels, peanut hulls and coconut coir pith powders to remove colour in a textile industry wastewater, experiments were performed. The experiments were conducted at pH of 7 with different process parameters like adsorbent dosage, temperature, contact time and agitator speed using batch adsorption method. From the experimental results, the maximum colour from the textile industry wastewater was obtained at an optimum adsorbent dosage of 350 mg, an optimum contact time of 73 min., an optimum temperature of 330 K and an optimum agitator speed of 650 rpm. Further, from the validation experiments, it was found that the maximum colour removal percentage in textile industry wastewater is about 75.2%, 78.3%, 86.6% and 81.7 % respectively for neem leaves, orange peels, peanut hulls and coconut coir pith powders. This result was higher than the results obtained by different process parameters for various bio-adsorbents. Finally, from the results of adsorption study, it was concluded that bio-adsorbents used as a coagulant for removing the colour from textile industry wastewater especially peanut hulls powder because of its higher adsorptive capacity than other bio-adsorbents used in this study.
DESALINATION AND WATER TREATMENT
The removal of Congo red dye from aqueous solutions by adsorption reaction onto three distinct adsorbents: graphene oxide (GO), graphene oxide-grafted-3,3'-diaminobenzidine (GO/ DAB), and GO/DAB-grafted-ethylenediaminetetraacetic acid (GO/DAB/EDTA) was investigated in batch experiments. The study of the effects of pH and contacting time on adsorption systems is the first step in optimizing them. The results revealed that depending on the type of adsorbent, the optimum pH values and periods differed. The Congo red (CR) dye adsorptions onto the investigated adsorbents GO, GO/DAB, and GO/DAB/EDTA required pH (3.0, 7.0, and 5.0, respectively) and time (60, 30, and 45 min). The fundamental adsorption properties of the dye were evaluated using adsorption equilibrium isotherms, namely the Langmuir, Freundlich, and Dubinin-Radushkevich models. The maximum adsorption values (q max) were calculated using the Langmuir isotherm results, and they were 1,250; 1,428.5 and 1,438.1 mg/g for the adsorption of CR dye onto adsorbents GO, GO/DAB, and GO/DAB/EDTA, respectively, and these results proved the preference for prepared GO-derivatives over GO. The kinetic models, namely pseudo-first-order and pseudo-second-order, were employed to understand the mechanism of the adsorption process, and they fitted very well with the pseudo-second-order kinetic model, which relies on the assumption that chemisorption may be the rate-limiting step. This study reveals that the presence of functional groups and active sites on the studied adsorbent contributed to its high affinity for CR dye adsorption. As a result, they can be used as efficient and cost-effective dye adsorbents in industrial effluent. Thermodynamic parameters including enthalpy ΔH°, entropy ΔS°, free energy ΔG°, and activation energy E a of the adsorption process were calculated and used to interpret the results, which revealed that the adsorption systems were a spontaneous and endothermic process for GO and its composites. Also, low activation energy values (E a < 40 kJ/mol) were characteristics of the physisorption mechanism and diffusion-controlled process.
Orbital - The Electronic Journal of Chemistry, 2016
Vigna unguiculata seed husk powder has been investigated as low cost adsorbent for the removal of hazardous chemicals like Congo Red (CR) dye from aqueous solution. Various parameters such as effect of contact time, initial CR dye concentration, adsorbent dose, effect of pH, zero-point pH were studied. Batch adsorption technique was employed to optimize the process parameter. The result indicated that, the percentage adsorption of Congo Red increased with increase in contact time, dose of adsorbent and initial concentration of Congo Red and decreased with addition of salt. The adsorption of Congo Red was 78% at the optimum pH of 6. Adsorption equilibrium was found to be reached in 24 h for 5 to 25 g/50 mL Congo red concentrations. The Langmuir and Freundlich isotherm models were found to provide an excellent fitting of the adsorption data. The adsorption of CR follows Second order rate kinetics. Thermodynamic parameter (ΔG o) showed that it was an exothermic process. This adsorbent was found to be effective and economically attractive.
In this study, adsorption equilibrium and kinetic studies for the removal of crystal violet (CV) from an aqueous solution were investigated using a batch adsorption process. The activated carbon was prepared by carbonizing the avocado pear seed at a carbonization temperature of 500 O C for 1hr and was impregnated with a 30% concentration of aqueous HCl solution which was further activated in a muffle furnace at a temperature of 500 O C for 1hr. The avocado pear seed activated Carbon obtained was characterized using proximate analysis, Fourier Transform Infra-Red Spectrophotometer (FT-IR) analysis and Scanning Electron Microscope (SEM) analysis. The effect of various adsorption parameters such as contact time (15-150 min), initial dye concentration (25-150 mg/L), adsorbent dosage (1-9 g), particle size and pH of dye solution were investigated. The adsorption equilibrium data were fitted into different isotherm models and the Langmuir model exhibited the best fit which implied that the adsorption of CV dyes onto avocado pear seed activated carbon was monolayer and the adsorbent surface was homogeneous and also; adsorption energy was uniform for all sites and there was no transmigration of adsorbate in the plane of the surface. The kinetic studies revealed that the adsorption data fitted well to the pseudo-second-order model with a high correlation coefficient of 0.977 when compared to other models, thus; signifying that the adsorption's mechanism was chemisorption. APSAC shows a much better adsorption capacity for CV dye removal having a maximum adsorption capacity of 3.3254 mg/g and percentage removal of 99.995 %. Hence, APSAC can be used as an effective and low-cost adsorbent for the removal of CV dye from an aqueous solution.
Acid-Base Properties of the Adsorption of Synthetic Dyes from Solutions
The presence of synthetic dyes is often underestimated in environmental protection. However, it has been demonstrated the impact of colored compounds in ecology and human health. Green tea (GT) and peppermint (PM) tea bag wastes were used as potential adsorbents of dyes from aqueous solutions to evaluate the effect of pH on the adsorption. Basic yellow 57, basic blue 99 and crystal violet were chosen as model dyes due to their widespread use in the industry. Dye solutions at different pH values were placed in contact with the adsorbents in batch experiments at room temperature. Results indicate that crystal violet is totally removed from the solution by the adsorbents (100% removal), followed basic blue 99 and basic yellow. PM reports the highest dye removal. Our data was compared to recently published reports, indicating their potential applicability to real wastewaters, as it is optimum at neutral pH values. These results demonstrate that these materials are excellent and cost-effective candidates for the removal of dye pollutants from contaminated solutions.
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.
A novel agricultural waste adsorbent for the removal of cationic dye from aqueous solutions
Journal of Hazardous Materials, 2009
In this paper, pineapple stem (PS) waste, an agricultural waste available in large quantity in Malaysia, was utilized as low-cost adsorbent to remove basic dye (methylene blue, MB) from aqueous solution by adsorption. Batch mode experiments were conducted at 30 • C to study the effects of initial concentration of methylene blue, contact time and pH on dye adsorption. Equilibrium adsorption isotherms and kinetic were investigated. The experimental data were analyzed by the Langmuir and Freundlich models and the isotherm data fitted well to the Langmuir isotherm with monolayer adsorption capacity of 119.05 mg/g. The kinetic data obtained at different concentrations were analyzed using a pseudo-firstorder and pseudo-second-order equation and intraparticle diffusion equation. The experimental data fitted very well the pseudo-second-order kinetic model. The PS was found to be very effective adsorbent for MB adsorption.
Cationic dyes removal from wastewater by adsorptive method: A systematic in-depth review
2021
One of the most pressing environmental problems is the existence of synthetic dyes in industrial wastewaters. The presence of dyes in wastewater can cause severe problems to human beings and aquatic life, and that warrants removal from aqueous medium. Amongst the multiple strategies to treat dye-contaminated water, adsorption is considered superior because of low cost, flexibility, ease of operation and lower energy consumption. Many adsorbents, including carbon-based materials, biomaterials, nanomaterials, Schiff bases, metal-organic frameworks as well as natural and synthetic polymers, have been successfully applied in cationic dyes remediation. The current review article provides literature information about cationic dyes, various treatment strategies, principles of adsorption and recent trends in adsorbents application were discussed at length. The applicability of various isotherms and kinetic models for cationic dyes removal by diversified adsorbents is also highlighted here. ...
Removal of Direct Dyes from Aqueous Solution Using Various Adsorbents
Dyestuff production units and dyeing units have always had a pressing need for techniques that allow economical pre-treatment for colour in the effluent. The effectiveness of adsorption for dye removal from wastewaters has made it an ideal alternative to other expensive treatment options. Removal of direct dyes [direct yellow 50 (DY50), direct red 80 (DR80) and direct blue 71(DB71)] from an aqueous solution by different adsorbents such as activated carbon, raw kaolinite and montmorillonite was investigated. The adsorption isotherm data were fitted to the Langmuir isotherm. Parameters of the Langmuir isotherm have been determined using the adsorption data. Adsorption capacity of RAC (commercial activated carbon), HAC (activated carbon obtained from shell of hazelnut), KC ( raw kaolinite) and MC (montmorillonite) increased in the following order: DY50 > DR80 > DB71, DB71>DR80>DY50, DR80>DB71>DY50 and DB71>DR80 (DY50 showed no absorption) for the direct dyes, respectively.