scholarly journals Statistical Optimization and Modeling of Methylene Blue Adsorption Onto Graphene Oxide in Batch and Fixed-Bed Column

2018 ◽  
Vol 5 (1) ◽  
pp. 21-34
Author(s):  
Habib Koolivand ◽  
Afsaneh Shahbazi

The batch and fixed-bed column adsorption of methylene blue (MB), a widely used toxic dye, onto graphene oxide (GO) was investigated in this study. GO was synthesized using modified Hummers method and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Response surface methodology (RSM) was employed to optimize batch and fixed-bed column adsorption of MB. Batch adsorption experiments were carried out by central composite design (CCD) with three input parameters including initial MB concentration (C0: 50-350 mg/L), GO dosage (D: 0.05-0.7 g/L), and pH (pH: 3-9). The adsorption capacity of GO for MB removal in the optimum level of factors (C0: 50 mg/L, D: 0.05 g/L, and pH: 8.5) was predicted by the model to be 700 mg/g. Adsorption kinetic data were tested using pseudo-first order, pseudo-second order, and intraparticle diffusion models. The kinetic experimental data was well fitted with pseudo-second order kinetic model (R2=1). The adsorption of MB onto GO demonstrated that Langmuir model (R2=0.999) could better fit the adsorption data than the Freundlich model (R2=0.914). Thermodynamic parameters including enthalpy (ΔH), Gibbs free energy (ΔG), and entropy (ΔS) were also investigated. Positive value of ΔH and negative value of ΔG indicated the endothermic and spontaneous nature of the adsorption. The positive value of ΔS also showed increased randomness at the solid/liquid interface during the adsorption of MB onto GO. The real wastewater experiment at optimum conditions showed high performance of adsorbent in the presence of other ions. Fixed-bed column experiments were designed using a three-factor, three-level Box-Behnken design (BBD) to investigate the single and combined effects of influent concentration (Cinf: 50-200 mg/L), flow rate (Q: 0.25-0.8 mL/min), and bed height (BH: 3-7 cm). MB removal from GO in the optimum levels of factors (Cinf: 51 mg/L, BH: 5.7 cm, and Q: 0.25 mL/min) was predicted by the model to be 86% (qe=459.3 mg/g). Fixed-bed experimental data were also fitted well to the Thomas and BDST models. The results showed that GO can be used as an efficient adsorbent for batch and fixed-bed adsorption of cationic dyes from synthetic and real wastewater.

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Seraj Anwar Ansari ◽  
Fauzia Khan ◽  
Anees Ahmad

Cauliflower leaf powder (CLP), a biosorbent prepared from seasonal agricultural crop waste material, has been employed as a prospective adsorbent for the removal of a basic dye, methylene blue (MB) from aqueous solution by the batch adsorption method under varying conditions, namely, initial dye concentration, adsorbent dose, solution pH, and temperature. Characterization of the material by FTIR and SEM indicates the presence of functional groups and rough coarse surface suitable for the adsorption of methylene blue over it. Efforts were made to fit the isotherm data using Langmuir, Freundlich, and Temkin equation. The experimental data were best described by Freundlich isotherm model, with an adsorption capacity of 149.22 mg/g at room temperature. To evaluate the rate of methylene blue adsorption onto CLP, pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were employed. The experimental data were best described by the pseudo-second-order kinetic model. Evaluation of thermodynamic parameters such as changes in enthalpy, entropy, and Gibbs’ free energy showed the feasible, spontaneous, and exothermic nature of the adsorption process. On the basis of experimental results obtained, it may be concluded that the CLP prepared from agricultural waste has considerable potential as low-cost adsorbent in wastewater treatment for the removal of basic dye, MB.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shazia Perveen ◽  
Raziya Nadeem ◽  
Shaukat Ali ◽  
Yasir Jamil

Abstract Biochar caged zirconium ferrite (BC-ZrFe2O5) nanocomposites were fabricated and their adsorption capacity for Reactive Blue 19 (RB19) dye was evaluated in a fixed-bed column and batch sorption mode. The adsorption of dye onto BC-ZrFe2O5 NCs followed pseudo-second-order kinetics (R 2 = 0.998) and among isotherms, the experimental data was best fitted to Sips model as compared to Freundlich and Langmuir isotherms models. The influence of flow-rate (3–5 mL min−1), inlet RB19 dye concentration (20–100 mg L−1) and quantity of BC-ZrFe2O5 NCs (0.5–1.5 g) on fixed-bed sorption was elucidated by Box-Behnken experimental design. The saturation times (C t /C o  = 0.95) and breakthrough (C t /C o  = 0.05) were higher at lower flow-rates and higher dose of BC-ZrFe2O5 NCs. The saturation times decreased, but breakthrough was increased with the initial RB19 dye concentration. The treated volume was higher at low sorbent dose and influent concentration. Fractional bed utilization (FBU) increased with RB19 dye concentration and flow rates at low dose of BC-ZrFe2O5 NCs. Yan model was fitted best to breakthrough curves data as compared to Bohart-Adams and Thomas models. Results revealed that BC-ZrFe2O5 nanocomposite has promising adsorption efficiency and could be used for the adsorption of dyes from textile effluents.


Author(s):  
Kouassi Kouadio Dobi-Brice ◽  
Yacouba Zoungranan ◽  
Dje Daniel Yannick ◽  
Ekou Lynda ◽  
Ekou Tchirioua

Aims: Pollution by wastewaters from various urban activities such as artisanal dyeing plants is a real problem for developing countries. The treatment of wastewater by the adsorption method is carried out by means of less expensive and available adsorbent media. Two techniques of the adsorption method are possible: adsorption in continuous mode (column adsorption) and adsorption in discontinuous mode (batch adsorption). The choice of the continuous adsorption technique is justified by its ability to process large volumes of solutions. In this study, dyes contained in wastewater from artisanal dyeing plants were removed by continuous adsorption in a fixed-bed column of deactivated lichen biomass (Parmotrema dilatatum). Study Design: Random design Place and Duration of Study: Laboratory of Thermodynamics and Environmental Physico-Chemistry (University Nangui Abrogoua, Ivory Coast) between May 2020 and October 2020. Methodology: Four (4) categories of wastewater were collected in artisanal cotton and leather dyeing plants through two municipalities of the city of Abidjan, economic capital of Ivory Coast. Two (2) wastewaters colored in blue from dyeing of cotton boubous and jeans and two (2) wastewaters colored in red from dyeing of leather jackets and bags. These wastewaters were treated through the fixed bed column of deactivated lichens. The column feed rate was set at 0, 07 L.min-1 and the adsorbent bed mass at 100 g. Results: The study showed that, regardless of the nature of the dyed object and regardless of the target dye, the amount of dye adsorbed was better with waters of higher initial concentration. Thus the best amount of adsorbed dye is 44.444 mg.g-1 and the best removal rate is 97.9%. These values are obtained with the red wastewater of bags (RWB) treatment which was the most concentrated wastewater. Conclusion: Good efficiency of deactivated lichen bed as adsorbent for the in situ removal of dyes from wastewater by continuous adsorption.


2011 ◽  
Vol 64 (3) ◽  
pp. 654-660 ◽  
Author(s):  
Xiuli Han ◽  
Wei Wang ◽  
Xiaojian Ma

The adsorption potential of lotus leaf to remove methylene blue (MB) from aqueous solution was investigated in batch and fixed-bed column experiments. Langmuir, Freundlich, Temkin and Koble–Corrigan isotherm models were employed to discuss the adsorption behavior. The results of analysis indicated that the equilibrium data were perfectly represented by Temkin isotherm and the Langmuir saturation adsorption capacity of lotus leaf was found to be 239.6 mg g−1 at 303 K. In fixed-bed column experiments, the effects of flow rate, influent concentration and bed height on the breakthrough characteristics of adsorption were discussed. The Thomas and the bed-depth/service time (BDST) models were applied to the column experimental data to determine the characteristic parameters of the column adsorption. The two models were found to be suitable to describe the dynamic behavior of MB adsorbed onto the lotus leaf powder column.


2014 ◽  
Vol 16 (4) ◽  
pp. 676-689 ◽  

<div> <p>In the present study, batch adsorption studies were performed for the removal of malachite green and acid blue 161 dyes from aqueous solutions by varying parameters such as contact time, waste marble dust amount, initial dye concentration and temperature. The equilibrium adsorption data were analyzed by Langmuir, Freundlich and Temkin adsorption isotherm models. The Langmuir and Freundlich adsorption models agree well with experimental data. The pseudo-second order, intraparticle intraparticle diffusion and Elovich kinetic models were applied to the experimental data in order to describe the removal mechanism of dye ions by waste marble dust. The pseudo-second order kinetic was the best fit kinetic model for the experimental data. Thermodynamics parameters such as Δ<em>G</em>, Δ<em>H</em> and Δ<em>S </em>were also calculated for the adsorption processes. The experimental data were used to construct an artificial neural network (ANN) model to predict removal of malachite green and acid blue 161 dyes by waste marble dust. A three-layer ANN, an input layer with four neurons, a hidden layer with 12 neurons, and an output layer with one neuron is constructed. Different training algorithms were tested on the model to obtain the proper weights and bias values for ANN model. The results show that waste marble dust is an efficient sorbent for malachite green dye and ANN network, which is easy to implement and is able to model the batch experimental system.</p> </div> <p>&nbsp;</p>


2019 ◽  
Vol 19 (7) ◽  
pp. 1929-1937 ◽  
Author(s):  
Nguyen Chi Thanh ◽  
Boonchai Wichitsathian ◽  
Chatpet Yossapol ◽  
Watcharapol Wonglertarak ◽  
Borano Te

Abstract Arsenic-polluted water is a global concern and puts millions of people at risk of developing cancer. The improvement of aqueous solution coexisting with arsenite and arsenate using iron mixed porous clay pellets was investigated in batch and fixed-bed column systems. Batch studies showed that the removal rate occurred in two main phases with an equilibrium time of 52 h. The pseudo-second-order model well described the experimental data. Isotherm data were well fitted by the Langmuir–Freundlich model. The removal efficiency was significantly reduced in alkaline solution and the presence of phosphate ions. The column study revealed that the breakthrough time and saturation time increased with lower feeding flow rate, higher bed height, and lower initial adsorbate concentration. The Thomas model provided good performance for predicting the column experimental data.


Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 852
Author(s):  
Sicong Yao ◽  
Massimiliano Fabbricino ◽  
Marco Race ◽  
Alberto Ferraro ◽  
Ludovico Pontoni ◽  
...  

Digestate, as an urban solid waste, was considered as an innovative adsorbent for colorant polluted wastewater. Batch adsorption experiments were carried out using digestate as an adsorbent material to remove various dyes belonging to different categories. The removal rate and adsorption capacity of dyes were evaluated and the dose of digestate, contact time, and initial dye concentration were studied. The maximum removal rate was approximately 96% for Methylene Blue. The equilibrium time for the Methylene Blue was 4 h, while for other dyes, a longer contact time was required to reach the equilibrium. The suspicion of colloidal matter release into the solution from solid fraction of the digestate led to the investigation of the consequence of a washing step of the digestate adsorbent upstream the adsorption experiment. Washed and not washed adsorbents were tested and the differences between them in terms of dye removal were compared. Moreover, experimental data were fitted by pseudo-first order, pseudo-second order, and intra-partial diffusion kinetic models as well as Langmuir, Freundlich, and Sips isotherm models. The results from fitted models showed that the adsorption of various dyes onto the digestate was mostly well fitted by the Langmuir isotherm and pseudo-second-order kinetic model.


2017 ◽  
Vol 77 (1) ◽  
pp. 91-100 ◽  
Author(s):  
Dan Chen ◽  
Jun Zhou ◽  
Hongyu Wang ◽  
Kai Yang

Abstract There is an increasing need to explore effective and clean approaches for hazardous contamination removal from wastewaters. In this work, a novel bead adsorbent, polyvinyl alcohol–graphene oxide (PVA-GO) macroporous hydrogel bead was prepared as filter media for p-nitrophenol (PNP), dye methylene blue (MB), and heavy metal U(VI) removal from aqueous solution. Batch and fixed-bed column experiments were carried out to evaluate the adsorption capacities of PNP, MB, and U(VI) on this bead. From batch experiments, the maximum adsorption capacities of PNP, MB, and U(VI) reached 347.87, 422.90, and 327.55 mg/g. From the fixed-bed column experiments, the adsorption capacities of PNP, MB, and U(VI) decreased with initial concentration increasing from 100 to 400 mg/L. The adsorption capacities of PNP, MB, and U(VI) decreased with increasing flow rate. Also, the maximum adsorption capacity of PNP decreased as pH increased from 3 to 9, while MB and U(VI) presented opposite tendencies. Furthermore, the bed depth service Time (BDST) model showed good linear relationships for the three ions' adsorption processes in this fixed-bed column, which indicated that the BDST model effectively evaluated and optimized the adsorption process of PVA-GO macroporous hydrogel bead in fixed-bed columns for hazardous contaminant removal from wastewaters.


2019 ◽  
Vol 41 (3) ◽  
pp. 259-271
Author(s):  
Nguyen Quoc Bien ◽  
Nguyen Thi Hoang Ha

Water pollution with arsenic (As) and heavy metals has been a major considering issue because of their negative impact on ecosystems and human health. This study was conducted to evaluate the adsorption behavior of As and heavy metals by iron ore sludge modified by the addition of 10% sodium silicate solution and heating at 400°C (SBC2-400-10S) in both batches and fixed–bed column experiments. The kinetics showed that the removal of As and heavy metals by the adsorbent is a pseudo-second-order reaction. The adsorption data fitted well with Langmuir isotherm and provided Langmuir monolayer capacity (mg/g) of As and heavy metals in the following order: Pb (2.379) > Cd (2.008) > Zn (1.915) > Mn (1.692) > As (0.452). The column adsorption data were fairly well described by Thomas model, with the order of Thomas adsorption capacity following a similar trend as in the batch study. The results of this study indicated that SBC2-400-10S was a potential adsorbent for removal of As and heavy metals from solutions.


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