Equilibrium and kinetic studies on basic dye adsorption by oil palm fibre activated carbon (original) (raw)
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Desalination, 2008
The feasibility of activated carbon prepared from oil palm shell to remove methylene blue from aqueous solutions was investigated through batch and column studies. Batch experiments were carried out to study the adsorption isotherm and kinetics at 30°C, with the initial concentration of 50-500 mg/l and solution pH of 6.5. Equilibrium data were fitted to Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. The equilibrium data were best represented by the Langmuir isotherm model, with maximum monolayer adsorption capacity of 243.90 mg/g at 30°C. The adsorption process was found to be exothermic in nature. The kinetic data were fitted to pseudo-first-order, pseudo-second-order and intraparticle diffusion models, and it was found to follow closely the pseudo-second-order model. In column experiments, the effects of the initial dye concentration, bed height and flow rate on methylene blue adsorption were studied. The highest bed capacity of 40.86 mg/g was obtained using 100 mg/l initial dye concentration, 6 cm bed height and 20 ml/min flow rate.
Adsorption isotherm and kinetics of methylene blue on activated carbon prepared from coconut husk were determined from batch tests. The effects of contact time (1–30 h), initial dye concentration (50–500 mg/l) and solution temperature (30–50 • C) were investigated. Equilibrium data were fitted to Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. The equilibrium data were best represented by Langmuir isotherm model, showing maximum monolayer adsorption capacity of 434.78 mg/g. The kinetic data were fitted to pseudo-first-order, pseudo-second-order and intraparticle diffusion models, and was found to follow closely the pseudo-second-order kinetic model. Thermodynamic parameters such as standard enthalpy (H •), standard entropy (S •) and standard free energy (G •) were evaluated. The adsorption interaction was found to be exothermic in nature. Coconut husk-based activated carbon was shown to be a promising adsorbent for removal of methylene blue from aqueous solutions.
BioResources
The mechanism of methylene blue adsorption was investigated for palm kernel shell-derived activated carbon from the bulk solution to active sites. For different initial dye concentrations, 100 ppm methylene blue led to approximately 10 mg/g adsorption capacity while experiencing a decreasing trend at lower initial dye concentrations as follows: 50 ppm (approximately 5 mg/g) > 20 ppm (approximately 2 mg/g) > 5 ppm (approximately 0.5 mg/g). Based on the Boyd external diffusion model, the mechanism of methylene blue adsorption started with its diffusion from the bulk solution via the bounding film encapsulating the activated carbon. The adsorbed species occupied more than one class of active site with an adsorption rate of 0.54 mg/g.min, while the adsorption capacity accounted for 14.7 mg/g. The information about methylene blue offers useful insights into describing the steps of dye adsorption onto palm kernel shell-activated carbon.
The adsorption of methylene blue (MB) on activated carbon fiber (ACF) and granular activated carbon (ACG) was studied in a batch system. The effects of initial concentration, agitation time, solution pH, and temperature were examined. Adsorption isotherms were described using both the Langmuir and Freundlich models. It was found that the Langmuir model fits well with the experimental data. The pseudo-first-order, pseudo-second-order, and intra-particle diffusion models were used to examine the kinetics data. The results obtained showed that empirical kinetics data of both ACF and ACG were only well described by the second-order model. It was observed that the ACF has adsorption performance higher than that of ACG. Adsorption thermodynamics parameters were estimated and their values indicated that the adsorption of MB on ACF and ACG were endothermic and spontaneous processes. Thermodynamic results also indicate that the adsorption of MB on both adsorbents is by chemical interaction.
2014
The methylene blue dye removal from aqueous solution by using activated carbon derived from a biodegradable agricultural waste material like palm flower (Borassus aethiopum) as bio- adsorbent was investigated in this work The scanning electron microscopic analysis helps to identify the novel bio-adsorbent's surface. Batch experiments were carried out with different parameters like initial concentration, contact time, pH, adsorbent dosage and temperatures. The pseudo first order, pseudo second order, Elovich and intraparticle diffusion models were arrived with kinetic studies. The data obtained from equilibrium experiments were tested by Langmuir, Freundlich and Temkin adsorption isotherms. The maximum methylene blue dye removal is 92.50% at 0.1g/100ml adsorbent dose with 4mg/L dye concentration for 120min contact time at 7pH. The calculated adsorption capacity of the palm flower carbon was 10.42mg/g at 30 o C temperature. The equilibrium and kinetic data were well suited to the ...
Adsorption of methylene blue onto bamboo-based activated carbon: Kinetics and equilibrium studies
Bamboo, an abundant and inexpensive natural resource in Malaysia was used to prepare activated carbon by physiochemical activation with potassium hydroxide (KOH) and carbon dioxide (CO 2) as the activating agents at 850 • C for 2 h. The adsorption equilibrium and kinetics of methylene blue dye on such carbon were then examined at 30 • C. Adsorption isotherm of the methylene blue (MB) on the activated carbon was determined and correlated with common isotherm equations. The equilibrium data for methylene blue adsorption well fitted to the Langmuir equation, with maximum monolayer adsorption capacity of 454.2 mg/g. Two simplified kinetic models including pseudo-first-order and pseudo-second-order equation were selected to follow the adsorption processes. The adsorption of methylene blue could be best described by the pseudo-second-order equation. The kinetic parameters of this best-fit model were calculated and discussed.
Adsorption of methylene blue from an aqueous solution on to activated carbons from palm-tree cobs
Carbon, 1997
In this study, activated carbon prepared from hazelnut husk (HHAC) using zinc chloride as chemical activating agent was characterized by FT-IR spectroscopy, BET surface area, Boehm titration, SEM and elemental analyses. During adsorption from aqueous solution of methylene blue (MB) studied by the batch method, effects of many variables, including solution pH, agitation time, temperature and initial concentration were investigated. It was established that MB adsorption reached equilibrium at 120 min at pH 7.0 as the appropriate value and is more compatible with Langmuir adsorption isotherm with respect to Freundlich. MB adsorption capacity of HHAC was found to be 476.2 mg g −1 and MB adsorption kinetics corresponds well with pseudo second order model. Thermodynamic studies revealed that MB adsorption is a spontaneous and endothermic process.
Adsorption of Direct Blue 5 Dye by Activated Carbon as Adsorbent -Modeling and Kinetics
2013
In this study, a study has been carried on adsorption of direct black dye which is used in textile industries of Sanganer (Jaipur). The amount adsorbed on granular activated carbon at equilibrium was measured and the equilibrium data were tested for Langmuir Frendlich, Temkin and Dubinin-Radushkevich isotherms for their applicability. The experimental data satisfied Langmuir, Freundlich and Temkin adsorption isotherm having correlation coefficients R 2 > 0.98. The maximum monolayer coverage from Langmuir isotherm was 17.51 mg/g. The heat of adsorption process was estimated from Temkin isotherm to be 3.796 J/mol. The calculations of thermodynamic parameters indicated that the adsorption is spontaneous and exothermic. The adsorption is found to increase with increase in temperature. The adsorption studies with granular activated carbon fit the second order kinetic model with R 2 = 0.9997.
HATEM A. AL-AOH, 2013
The adsorption of acid red 27 dye on activated carbon fiber and granular activated carbon were studied in a batch system. The effects of initial concentration, agitation time, solution pH and temperature were examined. Adsorption isotherms were described using both the Langmuir and Freundlich models at three different temperatures. It was found that, the Langmuir model fits well with the experimental data at each temperature. The pseudo-first-order, pseudo-second-order and intra-particle diffusion models were used to examine the kinetics data. The results obtained showed that the empirical kinetics data of activated carbon fiber at 60 and 100 mg/L were well described only by the pseudo-second-order model. The intraparticle diffusion was involved at 200 mg/L for activated carbon fiber and at each tested concentration for granular activated carbon. It was observed that activated carbon fiber has a higher adsorption capacity and adsorption rate than that of granular activated carbon. Adsorption thermodynamic parameters were estimated and the values of ∆Hº, ∆Sº and ∆Gº obtained indicate that the adsorption of acid red 27 on activated carbon fiber and granular activated carbon were exothermic and spontaneous processes
Adsorption of Methylene Blue Using Oil Palm ( Elaeis Guaneensis ) Fronds as Activated Carbon
2016
The application of underutilized resources and eco-friendly adsorbents is studied as the substitute for the commercially available activated carbon which occurred at high cost. The carbon type adsorbents were prepared from oil palm frond (OPF). It is a domestic waste that comfortably used to eradicate basic dye, which is methylene blue (MB) from aqueous solution using the adsorption removal method. The oil palm frond activated carbon is used to adsorb methylene blue as one of the effluents from the textile industry by varying the concentration, mass of adsorbent used and contact time. The findings disclose that the most efficient condition to remove the color intensity of methylene blue is by using 0.4g mass of OPF activated carbon at 10 minutes of contact time, which was tested on the lowest concentration of 20 ppm. The results from this research have proven that the percentage removal of dye decreases as the initial dye concentration increases. The percentage removal on the effect...