scholarly journals Isotherms and thermodynamics of malachite green on CO2-activated carbon fibers

2021 ◽  
Author(s):  
Joon Hyuk Lee ◽  
Soon Hong Lee ◽  
Dong Hack Suh
Keyword(s):  
Adsorption Capacity ◽  
Malachite Green ◽  
Carbon Fibers ◽  
Surface Characteristics ◽  
Maximum Adsorption Capacity ◽  
Activated Carbon Fibers ◽  
The Past ◽  
Isotherms And Thermodynamics ◽  
Carbonaceous Adsorbents ◽  
Strong Acids

Abstract Carbonaceous adsorbents have received substantial attention in the past decades because of their porous surface characteristics. However, the majority use of strong acids for the surface modification and the subsequent surface decrease remains challenging. Here, we designed porous carbon fibers with the aid of CO2 during activation for effective malachite green (MG) adsorption. The physiochemical mechanisms have been characterized both experimentally and numerically to decipher the underlying relevance of CO2-activation on the MG adsorption capacity. The obtained samples are dominated by micropores, resulting in a high specific surface up to 1012 m2 g-1 via 60 min of CO2-activation. The adsorption isotherm was fitted to Langmuir with the maximum adsorption capacity of 555.56 mg L-1. Thermodynamics revealed endothermic in nature and the spontaneous adsorption process. By using the primary culprit of global warming, this work advances the design of carbonaceous adsorbents for cationic dye removal. (144/150)

CO2 adsorption capacity and kinetics in nitrogen-enriched activated carbon fibers prepared by different methods

2015 ◽  
Vol 281 ◽  
pp. 704-712 ◽  
Author(s):  
Noel Díez ◽  
Patricia Álvarez ◽  
Marcos Granda ◽  
Clara Blanco ◽  
Ricardo Santamaría ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Carbon Fibers ◽  
Co2 Adsorption ◽  
Activated Carbon Fibers ◽  
Co2 Adsorption Capacity

scholarly journals CuAl LDH/Rice Husk Biochar Composite for Enhanced Adsorptive Removal of Cationic Dye from Aqueous Solution

2020 ◽  
Vol 15 (2) ◽  
pp. 525-537 ◽  
Author(s):  
Neza Rahayu Palapa ◽  
Tarmizi Taher ◽  
Bakri Rio Rahayu ◽  
Risfidian Mohadi ◽  
Addy Rachmat ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Surface Area ◽  
Malachite Green ◽  
Rice Husk ◽  
Low Cost ◽  
Bet Surface Area ◽  
Maximum Adsorption Capacity ◽  
Cationic Dye ◽  
X Ray ◽  
Adsorptive Removal

The preparation of CuAl LDH and biochar (BC) composite derived from rice husk and its application as a low-cost adsorbent for enhanced adsorptive removal of malachite green has been studied. The composite was prepared by a one-step coprecipitation method and characterized by X-ray Diffraction (XRD), Fourier Transform Infra Red (FTIR), Brunauer-Emmett-Teller (BET), and Scanning Electron Microscopy - Energy Dispersive X-ray (SEM−EDX). The result indicated that CuAl LDH was successfully incorporated with the biochar that evidenced by the broadening of XRD peak at 2θ = 24° and the appearance of a new peak at 1095 cm−1 on the FTIR spectra. The BET surface area analysis revealed that CuAl/BC composite exhibited a larger surface area (200.9 m2/g) that the original CuAl LDH (46.2 m2/g). Surface morphological changes also confirmed by SEM image, which showed more aggregated particles. The result of the adsorption study indicated the composite material was efficient in removing malachite green with Langmuir maximum adsorption capacity of CuAl/BC reaching 470.96 mg/g, which is higher than the original CuAl LDH 59.523 mg/g. The thermodynamic analysis suggested that the adsorption of malachite green occurs spontaneously (ΔG < 0 at all tested temperature) and endothermic nature. Moreover, the CuAl/BC composite showed strong potential as a low-cost adsorbent for cationic dye removal since it showed not only a high adsorption capacity but also good reusability. Copyright © 2020 BCREC Group. All rights reserved

scholarly journals Removal of Arsenite from Water by Ce-Al-Fe Trimetal Oxide Adsorbent: Kinetics, Isotherms, and Thermodynamics

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Cuizhen Sun ◽  
Jinwei Qiu ◽  
Zhibin Zhang ◽  
Taha F. Marhaba ◽  
Yanhao Zhang
Keyword(s):  
Adsorption Capacity ◽  
Standard Free Energy ◽  
Entropy Change ◽  
Maximum Adsorption Capacity ◽  
Transmission Electron ◽  
Adsorbent Surface ◽  
Adsorption Mode ◽  
Freundlich Adsorption Isotherm ◽  
Pseudo Second Order ◽  
Isotherms And Thermodynamics

Ce-Al-Fe trimetal oxide adsorbent was prepared. The morphology characteristics of the new adsorbent were analysed by the transmission electron microscope (SEM) method. The SEM results implied its ability in the adsorption of As (III). To verify the analyses, bench-scale experiments were performed for the removal of As (III) from water. In the experiments of adsorption, As (III) adsorption capacity of the trimetal oxide adsorbent was presented significantly higher than activated aluminium oxide and activated carbon. As (III) adsorption kinetics resembled pseudo-second-order adsorption mode. When initial As (III) concentration was 3, 8, and 10 mg·L−1, the maximum adsorption capacity achieved was 1.48, 3.73, and 5.12 mg·g−1, respectively. In addition, the experimental adsorption data were described well by the Freundlich adsorption isotherm model at 20, 30, and 40°C. The enthalpy change(ΔS), the standard free energy(ΔG), and entropy change(ΔH)indicated that the nature of As (III) adsorption was exothermic and spontaneous with increasing randomness on the interface of solid and liquid. And the adsorption mechanism can be interpreted as chemisorption with As (III) multilayer coverage formation on the adsorbent surface.

scholarly journals Equilibrium, Thermodynamic and Mechanism Studies of Malachite Green Adsorption on Used Black Tea Leaves from Acidic Solution

2016 ◽  
Vol 64 ◽  
pp. 77-88 ◽  
Author(s):  
Mohammad Abul Hossain ◽  
Md. Lokman Hossain ◽  
Tanim Al Hassan
Keyword(s):  
Activation Energy ◽  
Adsorption Capacity ◽  
Malachite Green ◽  
Acidic Solution ◽  
Black Tea ◽  
Equilibrium Adsorption ◽  
Maximum Adsorption Capacity ◽  
Processing Temperature ◽  
Tea Leaves ◽  
Activation Energy Of Adsorption

This study reports the equilibrium adsorption mechanism and thermodynamics for the removal of Malachite Green (MG) from acidic solution using Used Black Tea Leaves (UBTL) as a low cost adsorbent. The effect of initial dye concentration, processing temperature and the presence of electrolytes on the adsorption from acidic solutions were investigated in batch process. Adsorption process was attained to the equilibrium at about 24 hours. Adsorption isotherms of MG on UBTL for different temperatures were constructed at pH 2.0 and the equilibrium adsorption data were analyzed using different model equations such as Langmuir, Freundlich, Temkin, Dubinin-Radushkevich (D-R), Harkin-Jura, Halsey, Elovich-Larionov and Flory-Huggens isotherms. The experimental results were reasonably correlated by Langmuir, Flory-Huggins and D-R models than other isotherm models. The maximum adsorption capacity (qm), intensity of adsorption (b) and separation factor (Rb) were calculated from Langmuir plot and activation energy of adsorption (Ead) was determined from D-R isotherm. At pH 2.0, the equilibrium adsorption capacity of UBTL to MG is 110 mg∙g-1 at 30°C, which was increased with increasing temperature suggested endothermic nature of adsorption. Thermodynamics parameters: ΔGads, ΔHads and ΔSads were calculated from Langmuir constant (b). The positive values of enthalpy and free energy, and negative value of entropy suggested that the adsorption is less spontaneous and surface migration or fragmentation of MG molecules on UBTL surface might be occur. Again, the low value of activation energy of adsorption (Ead = 0.3 kJ∙mol-1 <8 kJ∙mol-1) suggested that the adsorption is controlled by physical in nature. A possible mechanism involvement of protonation is proposed from the effect of electrolytes during the adsorption of MG on UBTL at pH 2.0.

scholarly journals Adsorption of Malachite Green From Aqueous Solution Using Hydroxyethyl Starch Hydrogel Improved by Graphene Oxide

2021 ◽  
Author(s):  
Alper Onder ◽  
Mehmet Rıza Kıvanç ◽  
Seçil Durmuş ◽  
Pinar Ilgin ◽  
Hava Ozay ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electron Microscope ◽  
Adsorption Capacity ◽  
Malachite Green ◽  
Hydroxyethyl Starch ◽  
Synthesis Method ◽  
Solution Concentration ◽  
Single Step ◽  
Maximum Adsorption Capacity ◽  
Bet Analysis

Abstract This study is the first report of the preparation of hydroxyethyl starch (HES) hydrogels rapidly crosslinked with divinyl sulfone in a single step and single pot. To develop the physical and chemical features of hydrogels, Graphene oxide (GO) nanoparticles were combined with the crosslinked HES. In addition to swelling studies, structural characterization of the samples was conducted with a scanning electron microscope (SEM) and transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), Brunauer–Emmett–Teller (BET) analysis and thermogravimetric analysis (TGA). For the removal of malachite green model dye by GO-HES, the effects of GO content, solution concentration, temperature, contact duration, dosage and pH on varying adsorption features were researched. Additionally, adsorption isotherms, kinetic and thermodynamic systematics were analyzed. The maximum adsorption capacity of GO-HES composite hydrogel was found to be 89.3 mg/g for Langmuir isotherm. The possible adsorption mechanism of the composite hydrogels for malachite green dye involved electrostatic, hydrogen bonding, and π–π interactions. In addition to reasonable cost and simple synthesis method, the prepared composite materials have potential use in wastewater treatment as adsorbents for the removal of dye from aqueous solutions due to efficient adsorption capacity.

THE CHANGES IN SURFACE CHARACTERISTICS AND PHOTOCATALYTIC ACTIVITY OF TiO2 LOADED ON ACTIVATED CARBON FIBERS AFTER UV IRRADIATION

2006 ◽  
Vol 05 (06) ◽  
pp. 927-934 ◽  
Author(s):  
RUSHENG YUAN ◽  
JINGTANG ZHENG ◽  
RONGBO GUAN
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Activated Carbon ◽  
Surface Morphology ◽  
Pore Structure ◽  
Epoxy Resin ◽  
Carbon Fibers ◽  
Uv Irradiation ◽  
Surface Characteristics ◽  
Activated Carbon Fibers

TiO 2 loaded on activated carbon fibers (ACF) was performed by using epoxy resin as the precursor of the link between them, followed by calcination at 460°C in N 2 atmosphere, and the changes in surface characteristics and photocatalytic activity after UV irradiation were investigated in detail. After UV irradiation, the pore structure and surface morphology of TiO 2-loaded ACF ( TiO 2/ ACF ) kept unchanged. The UV-Vis spectrum shifted toward shorter wavelengths than that before UV irradiation. XPS results showed that the hydroxyl and C – O groups increased, resulting in an increase in hydrophilicity of TiO 2/ ACF . All these changes caused the increased photocatalytic activity for methylene blue, and the activity was maintained without any decrease when it was used repeatedly. Even at the sixth cycle, its amount of MB removal was still slightly higher than suspended P25.

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