scholarly journals Study of adsorption mechanism of Congo Red on graphene oxide/PAMAM nanocomposite

2021 ◽  
Author(s):  
Mohammad Rafi ◽  
Babak Samiey ◽  
Chil-Hung Cheng
Keyword(s):  
Graphene Oxide ◽  
Kinetic Parameters ◽  
Congo Red ◽  
Kinetic Data ◽  
Pamam Dendrimer ◽  
Maximum Adsorption Capacity ◽  
Hydroxyl Groups ◽  
Experimental Conditions ◽  
Adsorption Sites ◽  
Rate Controlling Step

Graphene oxide/poly(amidoamine) (GO/PAMAM) nanocomposite adsorbed high quantities of congo red (CR) anionic dye in 0.1 M NaCl solution, with the maximum adsorption capacity of 198 mg·g−1. The kinetics and thermodynamics of adsorption were investigated to elucidate the effects of pH, temperature, shaking rate, ionic strength, and contact time. Kinetic data were analyzed by the KASRA model and the KASRA, ISO, and pore-diffusion equations. Adsorption adsorption isotherms were studied by the ARIAN model and the Henry, Langmuir, and Temkin equations. It was shown that adsorption sites of GO/PAMAM at experimental conditions were phenolic hydroxyl groups of GO sheets and terminal amine groups of PAMAM dendrimer. Analysis of kinetic data indicated that amine sites were located on the surface, and that hydroxyl sites were placed in the pores of adsorbent. CR molecules interacted with the adsorption sites via hydrogen bonds. The molecules were adsorbed firstly on the amine sites, and then on the internal hydroxyl sites. Adsorption kinetic parameters indicated that the interaction of CR to the –NH3+ sites was the rate-controlling step of adsorption of CR on this site and adsorption activation energies calculated for different parts of this step. On the other hand, kinetic parameters showed that the intraparticle diffusion was the rate-controlling step during the interaction of CR molecules to –OH sites and activation energy of this step was not calculable. Finally, the used GO/PAMAM was completely regenerated by using ethylenediamine.

scholarly journals Study of adsorption mechanism of Congo Red on graphene oxide/PAMAM nanocomposite

2021 ◽  
Author(s):  
Mohammad Rafi ◽  
Babak Samiey ◽  
Chil-Hung Cheng
Keyword(s):  
Graphene Oxide ◽  
Kinetic Parameters ◽  
Congo Red ◽  
Kinetic Data ◽  
Pamam Dendrimer ◽  
Maximum Adsorption Capacity ◽  
Hydroxyl Groups ◽  
Experimental Conditions ◽  
Adsorption Sites ◽  
Rate Controlling Step

Graphene oxide/poly(amidoamine) (GO/PAMAM) nanocomposite adsorbed high quantities of congo red (CR) anionic dye in 0.1 M NaCl solution, with the maximum adsorption capacity of 198 mg·g−1. The kinetics and thermodynamics of adsorption were investigated to elucidate the effects of pH, temperature, shaking rate, ionic strength, and contact time. Kinetic data were analyzed by the KASRA model and the KASRA, ISO, and pore-diffusion equations. Adsorption adsorption isotherms were studied by the ARIAN model and the Henry, Langmuir, and Temkin equations. It was shown that adsorption sites of GO/PAMAM at experimental conditions were phenolic hydroxyl groups of GO sheets and terminal amine groups of PAMAM dendrimer. Analysis of kinetic data indicated that amine sites were located on the surface, and that hydroxyl sites were placed in the pores of adsorbent. CR molecules interacted with the adsorption sites via hydrogen bonds. The molecules were adsorbed firstly on the amine sites, and then on the internal hydroxyl sites. Adsorption kinetic parameters indicated that the interaction of CR to the –NH3+ sites was the rate-controlling step of adsorption of CR on this site and adsorption activation energies calculated for different parts of this step. On the other hand, kinetic parameters showed that the intraparticle diffusion was the rate-controlling step during the interaction of CR molecules to –OH sites and activation energy of this step was not calculable. Finally, the used GO/PAMAM was completely regenerated by using ethylenediamine.

Preparation of Graphene Oxide Modified Rice Husk for Cr(VI) Removal

2019 ◽  
Vol 19 (11) ◽  
pp. 7035-7043 ◽  
Author(s):  
Tong Ouyang ◽  
Jidan Tang ◽  
Fang Liu ◽  
Chang-Tang Chang
Keyword(s):  
Graphene Oxide ◽  
Adsorption Capacity ◽  
Rice Husk ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorption Sites ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Alkaline Conditions ◽  
Rice Husk Biochar

The objective of this paper is to study the removal of Cr(VI) in aqueous solution by using a new graphene oxide-coated rice husk biochar composite (GO-RHB). GO-RHB is a synthetic material having a porous structure with lots of oxygen-containing functional groups and a large surface area that provide effective adsorption sites. Experiments showed that GO-RHB had higher adsorption capacity under acidic than under alkaline conditions. At pH of 2, GO-RHB has the maximum adsorption capacity(48.8 mg g−1). Equilibrium data obtained by fitting with the Langmuir and Freundlich models indicate that the reaction process was monolayer adsorption. The adsorption of Cr(VI) followed the pseudo-second-order kinetic model that illustrates chemical adsorption. Intraparticlediffusion studies further revealed that film diffusion was taking place. Moreover, the results of thermodynamics showed that the adsorption process was endothermic and spontaneous in nature. The removal mechanism of Cr(VI) was also explained in detail. The prepared adsorbent is highly efficient and might be useful than many other conventional adsorbent used for the removal of Cr(VI) from wastewater.

scholarly journals Uptake of phenol from aqueous solution by burned water hyacinth

2008 ◽  
Vol 10 (2) ◽  
pp. 43-49 ◽  
Author(s):  
Mohammed Uddin ◽  
Mohammed Islam ◽  
Mohammed Islam ◽  
Mohammed Abedin
Keyword(s):  
Aqueous Solution ◽  
Water Hyacinth ◽  
Second Order ◽  
Point Of Zero Charge ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Experimental Conditions ◽  
Adsorption Models ◽  
Adsorption Sites ◽  
Pseudo Second Order

Uptake of phenol from aqueous solution by burned water hyacinth The potential of burned water hyacinth (BWH) for phenol adsorption from aqueous solution was studied. Batch kinetic and isotherm studies were carried out under varying experimental conditions of contact time, phenol concentration, adsorbent dosage and pH. The pH at the point of zero charge (pHPZC) of the adsorbent was determined by the titration method and the value of 8.8 ± 0.2 was obtained. The FTIR of the adsorbent was carried out in order to find the potential adsorption sites for the interaction with phenol molecules. The Freundlich and Langmuir adsorption models were used for the mathematical description of adsorption equilibrium and it was found that the experimental data fitted very well to the Langmuir model. Maximum adsorption capacity of the adsorbent was found to be 30.49 mg/g. Batch adsorption models, based on the assumption of the pseudo-first-order and pseudo-second-order models, were applied to examine the kinetics of the adsorption. The results showed that kinetic data closely followed the pseudo-second-order model.

scholarly journals Three-dimensional double-network hydrogels of graphene oxide, alginate, and polyacrylonitrile for copper removal from aqueous solution

2019 ◽  
Vol 25 (6) ◽  
pp. 924-929 ◽  
Author(s):  
Jung-Weon Choi ◽  
Hee Jin Kim ◽  
Hayeon Ryu ◽  
Sanghwa Oh ◽  
Sang-June Choi
Keyword(s):  
Graphene Oxide ◽  
Adsorption Capacity ◽  
Adsorption Equilibrium ◽  
Three Dimensional ◽  
Maximum Adsorption Capacity ◽  
Order Model ◽  
Double Network ◽  
Adsorption Sites ◽  
Pseudo Second Order ◽  
Ft Ir

Three-dimensional (3D) double-network graphene oxide/alginate-polyacrylonitrile (GO/Ca-Alg2-PAN) composite hydrogels were synthesized via surface functionalization of GO to activate adsorption sites. The morphology and structure of the GO/Ca-Alg2-PAN were analyzed by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA-DSC). The results of the physicochemical analyses indicated that GO/Ca-Alg2-PAN was successfully synthesized by the combination of a 2D-structured graphene oxide with the alginate which was functionalized with the PAN polymer to generate the 3D double network composites. This functionalization approach contributed to an increase in Cu<sup>2+</sup> ion adsorption capacity. The maximum adsorption capacity of the GO/Ca-Alg2-PAN for Cu<sup>2+</sup> was 5.99 mmol/g. The results of adsorption kinetic experiments indicated that the GO/Ca-Alg2-PAN reached adsorption equilibrium within 147 mins at 2 mM Cu<sup>2+</sup> in accordance with a pseudo-second-order model.

scholarly journals GO/PAMAM as a High Capacity Adsorbent for Removal of Alizarin Red S: Selective Separation of Dyes

2020 ◽  
Vol 67 (4) ◽  
pp. 1124-1138
Author(s):  
Mohammad Rafi ◽  
Babak Samiey ◽  
Chil-Hung Chen
Keyword(s):  
Adsorption Capacity ◽  
High Capacity ◽  
Pamam Dendrimer ◽  
Alizarin Red S ◽  
Alkaline Media ◽  
Maximum Adsorption Capacity ◽  
Alizarin Red ◽  
Adsorption Sites ◽  
Diffusion Controlled ◽  
Amine Groups

Adsorption of Alizarin Red S (ARS) on graphene oxide/poly(amidoamine) (GO/PAMAM) was studied at different ARS initial concentrations, temperatures, pHs, shaking rates and contact times. Adsorption sites of GO/PAMAM were phenolic –OH (Ph) group of GO and amine groups (–NH2, –NH+ 3 and –NHR+2) of PAMAM dendrimer moieties of GO/PAMAM. At pH = 2 and 318 K, maximum adsorption capacity (qe,max) of the adsorbent was 1275.2 mg g–1 which is one of the highest capacity in the literature. Thus, GO/PAMAM in this work acted as a superadsorbent for ARS. At the incipient of adsorption, ARS– molecules were adsorbed on Ph sites that was reaction-controlled step, (Ea = 114.5 kJ mol–1). Adsorption of ARS–on the remaining sites was diffusion–controlled. In alkaline media, two other types of ARS molecules were identified during that were adsorbed on Ph and –NH+ 3 sites. Further increasing the pH of the solution, decreased the number these two sites and yielded a reduced adsorption capacity (qe,max). Methylene blue (MB), thionine (Th), pyronin Y (PY), acridine orange (AO), methyl blue (MEB) and janus green (JG) dyes were selectively separated from their mixtures with ARS molecules using GO/PAMAM at pH of 2. The used adsorbent was recycled fficiently by using ethylenediamine very fast.

scholarly journals Adsorption Kinetics for the Removal of Hazardous Dye Congo Red by Biowaste Materials as Adsorbents

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Sumanjit Kaur ◽  
Seema Rani ◽  
Rakesh Kumar Mahajan
Keyword(s):  
Congo Red ◽  
Low Cost ◽  
Correlation Coefficients ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Experimental Conditions ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The present work aims to investigate the removal of dye congo red from aqueous solutions by two low-cost biowaste adsorbents such as ground nut shells charcoal (GNC) and eichhornia charcoal (EC) under various experimental conditions. The effect of contact time, ionic strength, temperature, pH, dye concentration, and adsorbent dose on the removal of dye was studied. The kinetic experimental data were fitted to pseudo-first order, pseudo-second order, intraparticle diffusion, Elovich model, and Bangham’s model. Results imply that adsorption of congo red on these adsorbents nicely followed the second order kinetic model and maximum adsorption capacity was found to be 117.6 and 56.8 mg g−1for GNC and EC at 318 K, however it increases with increase in temperature for both adsorbents. Equilibrium isotherms were analyzed by Langmuir, Freundlich, Temkin, Dubinin and Radushkevich, and Generalized Isotherms. Freundlich isotherm described the isotherm data with high-correlation coefficients. The results of the present study substantiate that biowaste material GNC and EC are promising adsorbents for the removal of the dye congo red.

Kinetics and Isotherm Studies of Methyl Orange Adsorption Using Polyethyleneimine-Graphene Oxide Polymer Nanocomposite Beads

2019 ◽  
Vol 801 ◽  
pp. 304-310
Author(s):  
Jirah Emmanuel T. Nolasco ◽  
Elaine Nicole O. Cañeba ◽  
Karl Michael V. Edquila ◽  
Joel Ian C. Espita ◽  
Jem Valerie D. Perez
Keyword(s):  
Graphene Oxide ◽  
Methyl Orange ◽  
Adsorption Capacity ◽  
Kinetic Studies ◽  
Polymer Nanocomposite ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorption Sites ◽  
Wide Ph Range

Nanocomposite beads containing 2% chitosan (CS), 2% polyethyleneimine (PEI), and 1,500 ppm graphene oxide (GO) were synthesized for the removal of methyl orange (MO) from water. Characterization of the CS-PEI-GO beads using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) showed favorable adsorbent properties as given by the presence of numerous surface functional groups and a porous structure. Effects of different parameters such as pH, contact time, and initial concentration on the percentage removal of MO and adsorption capacity of the beads were investigated by performing batch adsorption experiments. MO removal of more than 85% was achieved by the beads across a wide pH range. Kinetic studies were performed and a pseudo-second order kinetic equation with R2 of 0.9999 was obtained. Furthermore, adsorption equilibrium data for MO were best described by the Toth isotherm model (R2 = 0.9644), suggesting multilayer adsorption on heterogeneous adsorption sites with a maximum adsorption capacity of 421.51 mg/g. Finally, FTIR and SEM analyses after adsorption confirmed the presence of MO on the surface of the beads and revealed an intact and stable structure. Overall, the excellent adsorption capability and multi-functionality demonstrated in this study show great potential of the synthesized material for wastewater treatment applications.

scholarly journals A Novel Fe3O4/Graphene Oxide Composite Prepared by Click Chemistry for High-Efficiency Removal of Congo Red from Water

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hongliu Jiang ◽  
Yao Cao ◽  
Fengtao Zeng ◽  
Zewu Xie ◽  
Fuan He
Keyword(s):  
Graphene Oxide ◽  
Fe3o4 Nanoparticles ◽  
Congo Red ◽  
High Efficiency ◽  
Ph Value ◽  
Click Reaction ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Magnetic Graphene Oxide ◽  
Modified Graphene Oxide

In this paper, a magnetic graphene oxide (MGO) composite was prepared by the click reaction between the alkyne-modified Fe3O4 nanoparticles and the azide-modified graphene oxide for the purpose of removing the Congo red (CR) dye from water. The deposition of the Fe3O4 nanoparticles on the graphene oxide to successfully prepare the MGO composite was evidenced by the Fourier-transform infrared spectrometer, wide-angle X-ray diffraction equipment, scanning electron microscope, thermal gravimetric analyzer, and Raman spectrometer. The value of saturation magnetization for the MGO composite was 34.9 emu/g. The CR absorption capacities of the MGO composite increased first and then decreased as the pH value increased. It was found that the maximum adsorption capacity of the MGO composite for the CR was as high as 769.2 mg/g. In the absorption-desorption experiment, the CR absorption capacities of the MGO composite from the second cycle to the fifth cycle remained stable to be about 130 mg/g. Moreover, both the Langmuir model for the adsorption isotherm and the pseudo-second-order kinetic model could be used to describe the CR absorption behaviors of the MGO composite.

scholarly journals Biosorption of methylene blue from aqueous solutions by modified mesoporous Simarouba glauca seed shell powder

2015 ◽  
Vol 17 (4) ◽  
pp. 701-715 ◽  
Keyword(s):  
Methylene Blue ◽  
Aqueous Solutions ◽  
Kinetic Data ◽  
Second Order ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Experimental Conditions ◽  
Pseudo Second Order ◽  
Simarouba Glauca ◽  
Shell Powder

<div> <p>The present study investigates the ability of formaldehyde treated <em>Simarouba glauca</em> seed shell powder for removal of methylene blue (MB) from aqueous solutions. Batch adsorption studies were carried out under various experimental conditions such as agitation time, dye concentration, adsorbent dose and pH. The adsorbent was characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), XRD, BET and CHNS analysis. The adsorption data were analysed using Langmuir, Freundlich, Temkin and Dubinin - Radushkevich isotherms. Equilibrium data fitted well to Langmuir isotherm with maximum adsorption capacity of 111.1 mg g <sup>-1</sup>. Adsorption kinetic data were verified using pseudo first order, pseudo second order and Intraparticle diffusion model. The kinetic data were found to fit well with pseudo second order model.</p> </div> <p>&nbsp;</p>

Adsorption and advanced oxidation of diverse pharmaceuticals and personal care products (PPCPs) from water using highly efficient rGO–nZVI nanohybrids

2020 ◽  
Vol 6 (8) ◽  
pp. 2223-2238 ◽  
Author(s):  
Arvid Masud ◽  
Nita G. Chavez Soria ◽  
Diana S. Aga ◽  
Nirupam Aich
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Personal Care Products ◽  
Advanced Oxidation ◽  
Zero Valent Iron ◽  
Redox Activity ◽  
Personal Care ◽  
Adsorption Sites ◽  
Reduced Graphene ◽  
Nanoscale Zero Valent Iron

Reduced graphene oxide-nanoscale zero valent iron (rGO–nZVI) nanohybrid, with tunable adsorption sites of rGO and unique catalytic redox activity of nZVI, perform enhanced removal of diverse PPCPs from water.

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