scholarly journals Preparation of Nano-Iron Loaded Cassava Fibre Composite Material for Hexavalent Chromium Removal

2021 ◽  
Vol 50 (11) ◽  
pp. 3373-3382
Author(s):  
Haobin Shi ◽  
Wenbin Zhang ◽  
Feng Chen ◽  
Qingsheng Shi ◽  
Fei Chen ◽  
...  
Keyword(s):  
Composite Material ◽  
Hexavalent Chromium ◽  
Fibre Composite ◽  
Removal Rate ◽  
Fiber Composite ◽  
Order Kinetic ◽  
Factors Affecting ◽  
Initial Concentration ◽  
Order Kinetic Model ◽  
Fibre Composite Material

Waste cassava fiber and tea polyphenols were used as carrier materials and reducing agents, respectively, to prepare nano-iron loaded cassava fiber composite (CF-FeNPs). This work investigated the factors affecting the removal of Cr(Ⅵ) by CF-FeNPs under different environmental conditions and the removal mechanism. The SEM characterization results show that as the initial Fe2+ concentration increases, the amount of nano-iron on the surface of the composite material increases. The results show that the increases of the initial Fe2+ content and dosage of CF-FeNPs can enhance the removal rate. Meanwhile, the decrease of the initial concentration of Cr(Ⅵ) solution and pH also beneficial for the removal performance. When pH=2.0 and the initial concentration of Cr(Ⅵ) is 10 mg/L, the removal rate of hexavalent chromium by CF-FeNPs can reach 81.4% within 2 h. The reaction conforms to the pseudo first-order kinetic model. The results of this study can provide technical reference for the remediation and treatment of Cr(VI)-containing wastewater.

Nanoparticle Fe3O4 magnetized activated carbon from Armeniaca sibirica shell for the adsorption of Hg(II) ions

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 6100-6120
Author(s):  
Yinan Hao ◽  
Yanfei Pan ◽  
Qingwei Du ◽  
Xudong Li ◽  
Ximing Wang
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Ph Value ◽  
Removal Rate ◽  
Freundlich Isotherm ◽  
Entropy Change ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
Initial Concentration

Armeniaca sibirica shell activated carbon (ASSAC) magnetized by nanoparticle Fe3O4 prepared from Armeniaca sibirica shell was investigated to determine its adsorption for Hg2+ from wastewater. Fe3O4/ASSAC was characterized using XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), and BET (Brunauer–Emmett–Teller). Optimum adsorption parameters were determined based on the initial concentration of Hg2+, reaction time, reaction temperature, and pH value in adsorption studies. The experiment results demonstrated that the specific surface area of ASSAC decreased after magnetization; however the adsorption capacity and removal rate of Hg2+ increased 0.656 mg/g and 0.630%, respectively. When the initial concentration of Hg2+ solution was 250 mg/L and the pH value was 2, the adsorption time was 180 min and the temperature was 30 °C, and with the Fe3O4/ASSAC at 0.05 g, the adsorption reaching 97.1 mg/g, and the removal efficiency was 99.6%. The adsorption capacity of Fe3O4/ASSAC to Hg2+ was in accord with Freundlich isotherm models, and a pseudo-second-order kinetic equation was used to fit the adsorption best. The Gibbs free energy ΔGo < 0，enthalpy change ΔHo < 0, and entropy change ΔSo < 0 which manifested the adsorption was a spontaneous and exothermic process.

scholarly journals Preparation of grafting copolymer of acrylic acid onto loess surface and its adsorption behavior

2020 ◽  
Vol 82 (4) ◽  
pp. 673-682
Author(s):  
Fengqin Tang ◽  
Di Gao ◽  
Li Wang ◽  
Yufeng He ◽  
Pengfei Song ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Adsorption Capacity ◽  
Removal Rate ◽  
Vinyl Pyrrolidone ◽  
Mineral Particle ◽  
Gravimetric Analysis ◽  
Order Kinetic ◽  
Experimental Conditions ◽  
Order Kinetic Model ◽  
Grafting Copolymer

Abstract Loess is a typical natural mineral particle distributed widely around the world, and it is inexpensive, readily accessible, and harmless to the environment. In this study, loess was modified by surface grafting copolymerization of functional monomers, such as acrylic acid, N-vinyl pyrrolidone, and N,N-methylenebisacrylamide as a cross-linking agent, which afforded a novel loess-based grafting copolymer (LC-PAVP). After being characterized by scanning electron microscopy, thermal gravimetric analysis and Fourier-transform infrared spectroscopy, its adsorption capacity and mechanism of removing lead ions (Pb2+) were investigated. With the study of the optimal experimental conditions, it was demonstrated that the removal rate of Pb2+ by LC-PAVP can reach up to 99.49% in 60 min at room temperature. It was also found that the kinetic characteristics of the adsorption capacity due to the pseudo-second-order kinetic model and the thermodynamics conformed well with the Freundlich model. In summary, as a lost-cost and eco-friendly loess-based adsorbent, LC-PAVP is a good potential material for wastewater treatment.

scholarly journals Modified Spruce Sawdust for Sorption of Hexavalent Chromium in Batch Systems and Fixed-Bed Columns

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5156
Author(s):  
Dororthea Politi ◽  
Dimitrios Sidiras
Keyword(s):  
Sulfuric Acid ◽  
Adsorption Capacity ◽  
Hexavalent Chromium ◽  
Diethylene Glycol ◽  
Fixed Bed ◽  
Second Order ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Pseudo Second Order

This study investigated the potential use of spruce sawdust that was pretreated with diethylene glycol and sulfuric acid for the removal of hexavalent chromium from wastewater. The sawdust pretreatment process was conducted at different temperatures and times. The adsorbent was characterized by quantitative saccharification, scanning electron microscopy, and Brunauer–Emmet–Teller surface area analysis. Adsorption capacity was studied for both batch and column processes. The experimental adsorption isotherms were simulated using seven isotherm models, including Freundlich and Langmuir models. By using the Langmuir isotherm model, the maximal Cr(VI) adsorption capacity of organosolv-pretreated spruce sawdust (qm) was 318.3 mg g−1. Furthermore, the kinetic data were fitted to Lagergren, pseudo-second-order, and intraparticle diffusion models, revealing that the adsorption of Cr(VI) onto spruce sawdust pretreated with diethylene glycol and sulfuric acid is best represented by the pseudo-second-order kinetic model. Three kinetic models, namely, the Bohart–Adams model, Thomas model, and modified dose–response (MDR) model, were used to fit the experimental data obtained from the column experiments and to resolve the characteristic parameters. The Thomas adsorption column capacity of the sawdust was increased from 2.44 to 31.1 mg g−1 upon pretreatment, thus, demonstrating that organosolv treatment enhances the adsorption capability of the material.

scholarly journals Adsorption of Hexavalent Chromium from Aqueous Solution Using Chemically Activated Carbon Prepared from Locally Available Waste of Bamboo (Oxytenanthera abyssinica)

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Tamirat Dula ◽  
Khalid Siraj ◽  
Shimeles Addisu Kitte
Keyword(s):  
Activated Carbon ◽  
Hexavalent Chromium ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Batch Adsorption ◽  
Koh Activation ◽  
Order Kinetic ◽  
Oxytenanthera Abyssinica ◽  
Equilibrium Data ◽  
Order Kinetic Model

This study reports on the adsorption of Hexavalent Chromium from aqueous solutions using activated carbon prepared from bamboo (Oxytenanthera abyssinica) waste by KOH activation heating in an electrical furnace at 1073 K for 3 hrs. Batch adsorption experiments were also carried out as a function of pH, contact time, initial concentration of the adsorbate, adsorbent dosage, and temperature of the solution. Kinetic studies of the data showed that the adsorption follows the pseudo-second-order kinetic model. Thermodynamic parameters showed that adsorption on the surface of BWAC was feasible, spontaneous in nature, and exothermic between temperatures of 298 and 318 K. The equilibrium data better fitted the Freundlich isotherm model for studying the adsorption behavior of Hexavalent Chromium by BWAC. IR spectrum for loaded and unloaded BWAC was obtained using FT-IR spectrophotometer. Adsorption efficiency and capacity of Hexavalent Chromium were found to be 98.28% at pH 2 and 59.23 mg/g at 300 K.

Assessment of Urtica as a low-cost adsorbent for methylene blue removal: kinetic, equilibrium, and thermodynamic studies

2015 ◽  
Vol 69 (7) ◽  
Author(s):  
Mohammad Peydayesh ◽  
Mojgan Isanejad ◽  
Toraj Mohammadi ◽  
Seyed Mohammad Reza Seyed Jafari
Keyword(s):  
Methylene Blue ◽  
Adsorption Process ◽  
Low Cost ◽  
Cost Effective ◽  
Sem Analysis ◽  
Order Kinetic ◽  
Solution Ph ◽  
Factors Affecting ◽  
Order Kinetic Model ◽  
Mb Adsorption

AbstractMethylene blue (MB) removal using eco-friendly, cost-effective, and freely available Urtica was investigated. The morphology of the adsorbent surface and the nature of the possible Urtica and MB interactions were examined using SEM analysis and the FTIR technique, respectively. Various factors affecting MB adsorption such as adsorption time, initial MB concentration, temperature, and solution pH were investigated. The adsorption process was analysed using different kinetic models and isotherms. The results showed that the MB adsorption kinetic follows a pseudo-second-order kinetic model and the isotherm data fit the Langmuir isotherm well. Thermodynamic parameters, such as ΔG°, ΔH°, and ΔS°, were also evaluated, and the results indicated that the adsorption process is endothermic and spontaneous in nature. The MB adsorption capacity of Urtica was found to be as high as 101.01 mg g

Effect of Operating Conditions on the Chemical Phosphate Removal Using during Ferrous Iron Oxidation

2013 ◽  
Vol 807-809 ◽  
pp. 478-485 ◽  
Author(s):  
Ting Li ◽  
Wen Yi Dong ◽  
Hong Jie Wang ◽  
Jin Nan Lin ◽  
Feng Ouyang ◽  
...  
Keyword(s):  
Ferrous Iron ◽  
Removal Rate ◽  
Iron Oxidation ◽  
Operating Conditions ◽  
Phosphate Removal ◽  
Order Kinetic ◽  
Ferrous Iron Oxidation ◽  
Order Kinetic Model ◽  
Time Required ◽  
Kinetics Of

In this study, the effect of operating parameters and the co-existing ions on the phosphate removal during the ferrous iron oxidation was investigated. Results showed that with the increase of DO and [Fe (II)]0, the final phosphate removal rate both increased. But with increasing of pH, the final phosphate removal rate firstly increased and then decreased when the pH was higher than 8.0. The co-existing ions affected the final removal rate significantly, and the kinetics of phosphate removal followed the pseudo-first-order kinetic model. The corresponding kobs trends for the cation followed the order of Cu2+>Mn2+>Zn2+>NH4+-N. The presence of Cu2+ promoted the phosphate removal significantly. Compared with the control, , the time required to achieve 40 % phosphate removal rate, at the condition of 0.5 mg/L Cu2+, reduced from 60 min to 10 s. However, the selective anions inhibited the phosphate removal, due to the formation of Fe-anions complexes. The effect of selective anions on the phosphate removal rate constant decreased in the order of SO42->Cl-> NO3-.

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