Adsorption of Organic Dyes by Carbonized and Chemically Activated Cassia Fistula Pods (original) (raw)
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2019
This study compares the adsorptive capacity of unmodified, modified, and carbonized Cassia fistula pod with a view to develop low cost effective adsorbent for the remover of methylene blue (MB) dye in aqueous solution. In lieu of this, thermodynamic studies, kinetics and adsorption isotherms were explored. The adsorbents were characterized by FTIR and SEM analysis before and after the adsorption of methylene blue (MB). None of the samples conformed to the pseudo-first-2 order reaction. The R values (range 0.816-0.987) of pseudo-second-order reaction for all the adsorbents indicates their 2 conformity to pseudo-second-order reaction. The Langmuir coefficient factor (R) values for all the adsorbents are between 0.223-0.429, therefore, the data did not conform to the model. Both unmodified and oxalic treated cassia fistula do not conform to Freundlich model, there was fair conformity with the carbonized cassia fistula while the EDTA treated cassia 2 fistula conformed strongly as the R value was close to unity at 0.864. The value of standard enthalpy (? Ho) for unmodified and EDTA-treated adsorbent are 45.5 KJ/mol and 50.7 KJ/mol respectively indicating MB adsorption onto them is a chemisorption process while that of carbonized and oxalic treated are 38.33 KJ/mol and 9.75 KJ/mol respectively indicating a physio-sorption process. All adsorption reactions are endothermic in nature and consistent with temperature effect.
Adsorption of congo red and methylene blue dyes on an ashitaba waste and a walnut shell-based activated carbon from aqueous solutions: Experiments, characterization and physical interpretations, 2020
Activated carbons were prepared from ashitaba waste and a walnut shell to study the adsorption mechanism of congo red and methylene blue dyes in aqueous solution. These adsorbents were characterized via XRD, FTIR and SEM techniques and the dye adsorption isotherms at three temperatures were quantified. A statistical physics model was applied to interpret the adsorption mechanism of tested dyes and adsorbents. Modeling results showed that these dyes were practically separated in the solution leading to an absence of the aggregation process. Adsorption orientations of dye molecules on the adsorbents changed depending on the temperature and nature of systems. The adsorption capacity of ashitaba waste activated carbon for the removal of congo red was significant thus indicating strong interactions between this dye and tested adsorbent. Calculated adsorption energy varied from 7.25 to 20.43 kJ/mol and they showed that the adsorption of both adsorbates occurred via physical interactions at different temperatures where the removal process was endothermic.
International Journal of Environmental Science and Technology, 2013
In the present study, Juglans regia shells were used to prepare activated carbon by acid treatment method. J. regia shell-based activated carbon was used for the adsorption of two synthetic dyes namely, a basic dye malachite green and an acid dye amido black 10B. The prepared adsorbent was crushed and sieved to three different mesh sizes 100, 600 and 1,000 lm. The adsorbent was characterized by scanning electron microscopy, surface acidity and zero-point charge. Batch experiments were carried out by varying the parameters like initial aqueous phase pH, adsorbent dosage and initial dye concentration. The equilibrium data were tested with Langmuir, Freundlich, Redlich-Peterson and Sips isotherm at three different temperatures 293, 300 and 313 K and it was found that the Freundlich isotherm best fitted the adsorption of both the dyes. Kinetic data were tested with pseudo first-order model and pseudo second-order model. The mechanism for the adsorption of both the dyes onto the adsorbent was studied by fitting the kinetic data with intraparticle diffusion model and Boyd plot. External mass transfer was found to be the rate-determining step. Based on the ionic nature of the adsorbates, the extent of film diffusion and intraparticle diffusion varied; both being system specific. Thermodynamic parameters were also calculated. Finally, the process parameters of each adsorption system were compared to develop the understanding of the best suitable system. Keywords Adsorption Á Malachite green Á Amido black Á Intraparticle diffusion Á Boyd plot Electronic supplementary material The online version of this article (
Journal of Hazardous Materials, 2011
Thespesia populnea is a large tree found in the tropical regions and coastal forests of India. Its pods were used as a raw material for the preparation of activated carbon. The prepared activated carbon was used for the adsorptive removal of Orange G dye from aqueous system. The effects of various parameters such as agitation time, initial dye concentration and adsorbent dosage were studied using response surface methodology (RSM). RSM results show that 0.54 g of activated carbon was required for the maximum adsorption of Orange G dye (17.6 mg L −1 ) within a time period of 4.03 h. Adsorption data were modeled using Freundlich and Langmuir adsorption isotherms. The adsorption of Orange G dye by activated carbon obeyed both Fruendlich and Langmuir isotherm. Adsorption kinetic data were tested using pseudo-zero, first, second-order and intraparticle diffusion models. Kinetic studies revealed that the adsorption followed pseudo-second-order reaction with regard to the intraparticle diffusion. FTIR spectral result indicated all the functional group except primary amines (3417 cm −1 ) and C N (1618 cm −1 ) were involved in the adsorption process. XRD data showed that Orange G dye adsorbed activated carbon might not induce the bulk phase changes. SEM results showed that the surface of the activated carbon was turned from dark to light color after dye adsorption.
Competitive Adsorption of Dyes (congo red, methylene blue, malachite green) on Activated Carbon
2010
This is to certify that the thesis entitled Competitive Adsorption of dyes (congo red, methylene blue, malachite green) on Activated carbon, submitted by Bibek Dash to National Institute of Technology, Rourkela is a record of bonafide project work under my supervision and is worthy for the partial fulfillment of the degree of Bachelor of Technology (Chemical Engineering) of the Institute. The candidate has fulfilled all prescribed requirements and the thesis, which is based on candidate's own work, has not been submitted elsewhere.
Chemical Engineering Journal, 2012
The adsorption of food dyes, Acid Yellow 6 (AY-6), Acid Yellow 23 (AY-23), and Acid Red 18 (AR-18) onto activated carbon obtained from flamboyant pods (Delonix regia) under optimized conditions (AC op ) was performed in this work. According to the pH study, the three dyes best adsorbed in acidic solutions (pH = 2). Ten isotherm models, four kinetic models, and the intraparticle diffusion model were applied to fit the experimental data. The Vieth-Sladek isotherm explained the adsorption of the three dyes very well, and the maximum adsorption amounts (Q m ) found for AY-6, AY-23, and AR-18 were 673.687, 643.041, and 551.799 mg g −1 , respectively. The pseudo-second order model gave the best experimental data fit, although its k 2 parameter indicated that other mechanisms were involved in the adsorption of AY-6 and AY-23. Similarly, the intraparticle diffusion model indicated that adsorption was governed by several mechanisms. AC op was shown to be a fast and effective adsorbent for the removal of AY-6, AY-23, and AR-18 from aqueous solutions.
Materials
The present study shows porous activated carbon obtained from Chenopodium quinoa Willd and Quillaja saponaria and their use as potential adsorbents to remove three types of dyes from aqueous solutions. The adsorption results were compared with commercial charcoal to check their efficiency. All porous carbon materials were activated using carbon dioxide and steam and fully characterized. Moreover, the steam-activated samples exhibited a high total pore volume with a BET surface area of around 800 m2 g−1. Batch adsorption experiments showed that commercial charcoal is the charcoal that offered the best adsorption efficiency for tartrazine and sunset yellow FCF. However, in the case of crystal violet, all activated carbons obtained from Chenopodium quinoa Willd and Quillaja saponaria showed the best captures, outperforming commercial charcoal. Molecular dockings of the dyes on the commercial charcoal surface were performed using AutoDock Vina. The kinetic results of the three isotherm’...
Equilibrium and kinetic studies on basic dye adsorption by oil palm fibre activated carbon
Oil palm fibre, an abundant agricultural by-product in Malaysia, was used to prepare activated carbon by physiochemical activation method. Adsorption isotherm of methylene blue onto the prepared activated carbon was determined by batch tests. The effects of various parameters such as contact time, initial methylene blue concentration and temperature were investigated, at solution pH of 6.5. The adsorption capacity was found to increase with increase in the three parameters studied. Equilibrium data were fitted to Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherms. The equilibrium data were best represented by the Langmuir isotherm, with maximum monolayer adsorption capacity of 277.78 mg/g at 30 • C. The adsorption kinetics was found to follow the pseudo-second-order kinetic model. Various thermodynamic parameters such as standard enthalpy (H •), standard entropy (S •) and standard free energy (G •) were evaluated. Oil palm fibre-based activated carbon was shown to be a promising material for adsorption of methylene blue from aqueous solutions.
Chemical and Process Engineering Research, 2015
Adsorption of Methylene Blue dye from aqueous solution onto Activated carbon derived from Acacia nilotica (Sunt tree) by chemical activation with ZnCl2, (SUNT-C2) has been studied using batch-adsorption techniques. This study was carried out to examine the adsorption capacity of the low-cost adsorbent (SUNT-C2) for the removal of Methylene Blue dye from aqueous solution. The influence of pH, initial dye concentration, adsorbent particle size, adsorbent dose and contact time on the adsorption process were also studied. Results revealed that adsorption rate initially increased rapidly, and the optimal removal efficiency was reached within about 100 mins. Further increase in contact time did not show significant change in equilibrium concentration; that is, the adsorption phase reached equilibrium. The adsorption isotherms could be fitted well by the Langmuir and Freundlich models. Also the adsorption process followed pseudo first order rate kinetics. Results indicate that, a new, en...