Synthesis of Hematite (α-Fe2O3) Nanostructures by Thermal Oxidation of Iron Sheet for Cr (VI) Adsorption

2018 ◽  
Vol 775 ◽  
pp. 395-401 ◽  
Author(s):  
Christian Laurence E. Aquino ◽  
Mikko James C. Bongar ◽  
Anfernee B. Silvestre ◽  
Mary Donnabelle L. Balela
Keyword(s):  
Water Vapor ◽  
Thermal Oxidation ◽  
Adsorption Process ◽  
Sem Images ◽  
Chromium Ion ◽  
Langmuir Adsorption ◽  
Monolayer Adsorption ◽  
Pseudo Second Order ◽  
Kinetic And Thermodynamic Studies ◽  
Positively Charged

In this study, hematite (α-Fe2O3) nanostructures were synthesized via thermal oxidation of Fe sheet in dry air and in water vapor. SEM images show nanoblades and nanowires growing on the surface of the sheet. Samples synthesized in water vapor generally produced larger nanostructures while samples oxidized in higher temperatures formed taller and slender nanostructures. The α-Fe2O3nanostructures were used as adsorbent for Cr (VI) in acidic medium. Chromium removal was highest with the samples synthesized at 650°C in water vapor with 95% efficiency. Kinetic and thermodynamic studies revealed that the adsorption process strongly followed pseudo-second order kinetics model and is endothermic. The process also follows the Langmuir adsorption isotherm model, suggesting that the process is described by homogeneous, monolayer adsorption. Adsorption of Cr (VI) onto hematite may be attributed to the electrostatic reaction between the positively charged hematite adsorbent and negative chromium ion.

scholarly journals Eggshell Powder as an Adsorbent for Removal of Fluoride from Aqueous Solution: Equilibrium, Kinetic and Thermodynamic Studies

2012 ◽  
Vol 9 (3) ◽  
pp. 1457-1480 ◽  
Author(s):  
R. Bhaumik ◽  
N. K. Mondal ◽  
B. Das ◽  
P. Roy ◽  
K. C. Pal ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Adsorption Process ◽  
Low Cost ◽  
Fluoride Removal ◽  
Contaminated Water ◽  
Fluoride Adsorption ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Kinetic And Thermodynamic Studies ◽  
Maximum Removal

A new medium, eggshell powder has been developed for fluoride removal from aqueous solution. Fluoride adsorption was studied in a batch system where adsorption was found to be pH dependent with maximum removal efficiency at 6.0. The experimental data was more satisfactorily fitted with Langmuir isotherm model. The kinetics and the factor controlling adsorption process fully accepted by pseudo-second-order model were also discussed. Eawas found to be 45.98 kJmol-1by using Arrhenius equation, indicating chemisorption nature of fluoride onto eggshell powder. Thermodynamic study showed spontaneous nature and feasibility of the adsorption process with negative enthalpy (∆H0) value also supported the exothermic nature. Batch experiments were performed to study the applicability of the adsorbent by using fluoride contaminated water collected from affected areas. These results indicate that eggshell powder can be used as an effective, low-cost adsorbent to remove fluoride from aqueous solution as well as groundwater.

scholarly journals Application of Biochar to the Remediation of Pb-Contaminated Solutions

2018 ◽  
Vol 10 (12) ◽  
pp. 4440 ◽  
Author(s):  
Maria Boni ◽  
Agostina Chiavola ◽  
Simone Marzeddu
Keyword(s):  
Adsorption Process ◽  
Chemical Characterization ◽  
Complete Removal ◽  
Order Model ◽  
Equilibrium Conditions ◽  
Sem Images ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Physical And Chemical

BIOTON® biochar, produced by a wood biomass pyrolysis process, which is usually applied as soil amendment, was investigated for a novel application, i.e., the adsorption of lead from contaminated solutions. The experimental activity included physical and chemical characterization of BIOTON®; and Scanning Electron Microscope (SEM) images to highlight its internal structure. The adsorption process was investigated through batch and column experiments. Adsorption kinetics showed very rapid achievement of equilibrium conditions, i.e., 50 mg/L and 100 mg/L initial Pb concentration at 2 h and 4 h, respectively. Complete removal also occurred within the same time. The Brunauer–Emmett–Teller model was a better fit for the equilibrium data of both Pb concentrations, whereas the kinetics were best represented by the pseudo second-order model. Column tests showed that the addition of biochar as an adsorbent media within the bed significantly extended the time of breakthrough and exhaustion, with respect to the column filled with soil only. The values found for the adsorption capacity of BIOTON®- versus lead-containing solutions were comparable to those reported for commercial adsorbents. Therefore, BIOTON® can be considered a valid option: It also offers the additional benefit of allowing the recovery of a residue, which alternately would need to be disposed of.

scholarly journals Removal of Cd(II) Ions from Simulated Wastewater by HCl Modified Cucumis sativus Peel: Equilibrium and Kinetic Study

2014 ◽  
Vol 7 ◽  
pp. ASWR.S16488 ◽  
Author(s):  
Ruchi Pandey ◽  
Nasreen Ghazi Ansari ◽  
Ram Lakhan Prasad ◽  
Ramesh Chandra Murthy
Keyword(s):  
Cucumis Sativus ◽  
Adsorption Process ◽  
Order Reaction ◽  
Ion Concentration ◽  
Second Order Reaction ◽  
Monolayer Adsorption ◽  
Optimum Ph ◽  
Pseudo Second Order ◽  
Simulated Wastewater ◽  
Maximum Removal

This paper describes the adsorption of Cd(II) ions from aqueous solutions by modified Cucumis sativus peel (CSP) by HCl treatment. The optimum pH, adsorbent mass, contact time, and initial ion concentration were determined. The maximum removal efficiency was 84.85% for 20 mg/L Cd(II) ion at pH 5. The adsorption isotherms were obtained using concentrations of the metal ions ranging from 5 to 150 mg/L. The adsorption process follows Langmuir isotherm and pseudo-second-order reaction kinetics. CSPs exhibit monolayer adsorption capacity of 58.14 mg/g at 298 K. The paper also discusses the thermodynamic parameters of the adsorption (the Gibbs free energy, entropy, and enthalpy). Our results establish that the adsorption process was spontaneous and endothermic under normal conditions.

scholarly journals Adsorptive Capacity of Malachite Green onto Mg/M3+ (M3+=Al and Cr) LDHs

2021 ◽  
Keyword(s):  
Aqueous Solution ◽  
Malachite Green ◽  
High Stability ◽  
Adsorption Process ◽  
Adsorptive Capacity ◽  
Xrd Pattern ◽  
Langmuir Adsorption ◽  
Stability Structure ◽  
Pseudo Second Order ◽  
Double Hydroxides

<p>Layered double hydroxides (LDHs) of MgM3+ (M3+=Al and Cr) were synthesized by coprecipitation method to form Mg/Al and Mg/Cr LDHs. The materials were applied as adsorbents of malachite green in aqueous solution. The physical properties of Mg/Al and Mg/Cr were analyzed using XRD, FTIR, BET and TGDTA characterizations. The XRD pattern shows the characteristic of LDHs which has diffraction at 11.470 (003) and at 34.690 (012) for Mg/Al and 12.450 (003) and at 380 (012) for Mg/Cr. The interlayer spaces of Mg/Al and Mg/Cr LDHs were 7.71 Å and 7.62 Å, respectively. The surface area of Mg/Al was higher than Mg/Cr. The FTIR spectra confirm that the intense peak at 1385 cm-1 denotes vibration of nitrate bond and M-O band in under 1000 cm-1. Thus the Mg/Al and Mg/Cr LDHs were applied as adsorbents to remove malachite green in aqueous solution. The results of malachite green adsorption showed that malachite green was adsorbed onto Mg/Al and Mg/Cr followed pseudo second order and Langmuir adsorption parameter. The adsorption capacity of malachite green for Mg/Al and Mg/Cr was 44.444 mg/g and 33.784 mg/g, respectively. The thermodynamic study showed that the adsorption process was spontaneous, endothermic and favored in high temperature. The regeneration process showed that Mg/Al and Mg/Cr LDHs has high stability structure toward reusability of adsorbent until three cycles adsorption process.</p>

scholarly journals REMOVAL OF Pb2+ FROM AQUEOUS SOLUTION BY ADSORPTION ONTO COMPOSITE BASED ON EUCALYPTUS LEAF AND POLYANILINE

2017 ◽  
Vol 55 (1) ◽  
pp. 54
Author(s):  
Le Cao The ◽  
Vu Minh Tan ◽  
Phan Thi Binh
Keyword(s):  
Aqueous Solution ◽  
Adsorption Process ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Sem Images ◽  
Adsorption Data ◽  
Freundlich Adsorption Isotherm ◽  
Pseudo Second Order ◽  
Ir Analysis ◽  
Polymerization Method

Composite based on eucalyptus leaf and polyaniline (EL-PANi) was prepared by chemical polymerization method. It showed that the function groups belonging to polyaniline and eucalyptus leaf were found through IR analysis and the nanostructure of composite was explained by SEM images. The adsorption of  Pb2+ was carried out onto composite in aqueous solution via varying pH, contact time, and its initial concentration. The experimental adsorption data fitted well into Freundlich adsorption isotherm model (r2 = 0.9873). The adsorption process followed pseudo-second order kinetic with r2 = 0.9995. The maximum adsorption capacity of Pb2+ onto that composite was 172.4138 mg/g  by Langmuir equation and KF was 58.7527 mg/g by Freundlich one.

scholarly journals Effective removal of Cu2+ ions from polluted water using new bio-adsorbents

2021 ◽  
Vol 16 (2) ◽  
pp. 566-581
Author(s):  
B. Jagadeeswara Reddy ◽  
Sneha Latha Pala ◽  
Wondwosen Kebede Biftu ◽  
M. Suneetha ◽  
Kunta Ravindhranath
Keyword(s):  
Functional Groups ◽  
Adsorption Process ◽  
Polluted Water ◽  
Order Model ◽  
Langmuir Adsorption ◽  
Effective Removal ◽  
High Sorption ◽  
Pseudo Second Order ◽  
Surface Complex Formation ◽  
Polluted Lake

Abstract Sorbents derived from stem powders of Feronia limonia (FLSP), Amorphophallus paeoniifolius (APSP) and Pumpkin (Cucurbitapepo) (PSP) plants are investigated for the removal of Cu2+ ions from polluted water by adopting batch methods of extraction. Extraction conditions are optimized for the effective removal of Cu2+ ions. High sorption capacities are observed: 175.5 mg/g for FLSP; 140.4 mg/g for APSP; 130.0 mg/g for PSP. Effective pH ranges are: 5 to 10 for FLSP; 6 to 10 for APSP and 7 to 10 for PSP. The three spent adsorbents can be regenerated and used. Thermodynamic parameters indicate that the adsorption process is spontaneous, endothermic and have positive change in entropy values. As ΔH values are more than 25.0 kJ/mole, the adsorption may be due to surface complex formation between Cu2+ ions and functional groups of the adsorbents viz., -OH, -COOH etc. in the effective pH ranges. The good adsorption behaviour of FLSP even in acidic pHs may be due to the ion-exchange of Cu2+ ions for H+ ions of the functional groups of the adsorbent. The Langmuir adsorption isotherm and pseudo second-order model describe well the adsorption process. The sorbents are effectively applied to treat effluents from Cu-based industries and polluted lake water.

scholarly journals Porous Multifunctional Phenylcarbamoylated-β-Cyclodextrin Polymers for Rapid Removal of Organic Pollutants

2021 ◽  
Author(s):  
He Wang ◽  
Congzhi Liu ◽  
Xiaofei Ma ◽  
Yong Wang
Keyword(s):  
Organic Contaminants ◽  
Adsorption Process ◽  
Removal Rate ◽  
Pollutant Removal ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Monolayer Adsorption ◽  
Pseudo Second Order ◽  
Rapid Removal ◽  
Cyclodextrin Polymers

Abstract In this work, a series of porous multifunctional cyclodextrin (CD) polymers were fabricated using tetrafluoroterephthalonitrile (TFTPN) as the rigid crosslinker for the condensation of different functional phenylcarbamoylated-β-cyclodextrin derivatives to afford three preliminary polymerized adsorption materials such as poly nitrophenylcarbamoylated-β-cyclodextrin (NO2-CDP), poly trifluoromethylphenylcarbamoylated-β-cyclodextrin (F-CDP), poly chlorophenylcarbamoylated-β-cyclodextrin polymers (Cl-CDP) and a mix β- cyclodextrin polymer (X-CDP) prepared via a secondary crosslinking procedure of the above three materials. The X-CDP preparation process connects the `pre-formed nanoparticles and increases the presence of linkers inside the particles. At the same time, X-CDP exhibited porous structure with various functional groups such as nitro, chlorine, fluorine and hydroxyl. Those special characteristics render this material with good adsorption ability towards various pollutants in water, including tetracycline, ibuprofen, dichlorophenol, norfloxacin, bisphenol A, naphthol. Especially the maximum adsorption capacity for tetracycline at equilibrium reached 230.15 mg·g− 1, which is competitive with the adsorption capacities of other polysaccharides adsorbents. X-CDP removed organic contaminants much more quickly than other adsorbents, reaching almost ~ 95% of its equilibrium in only 30 s. The main adsorption process of the pollutants by X-CDP fitted the pseudo-second-order kinetic and Langmuir isotherm well, indicating that the adsorption process is monolayer adsorption. Moreover, X-CDP possessed the good reusability where the pollutant removal rate was only reduced 8.3% after five cycles.

Behavior of Phosphorus Adsorption from Aqueous Solutions on Modified Activated Alumina

2010 ◽  
Vol 152-153 ◽  
pp. 945-949
Author(s):  
Chun Sheng Ding ◽  
Ying Long Zou ◽  
Fang Ming Ni ◽  
Qian Fen Zhu
Keyword(s):  
Phosphorus Removal ◽  
Adsorption Process ◽  
Langmuir Adsorption Isotherm ◽  
Phosphorus Concentration ◽  
Activated Alumina ◽  
Phosphorus Adsorption ◽  
Langmuir Adsorption ◽  
Ph Values ◽  
Monolayer Adsorption ◽  
Adsorption Data

In the study, activated alumina was modified by calcium chloride, and after modification the phosphorus removal from aqueous solution increased by 13% or so. Then the activated alumina with and without treatment were subjected to characterization by the methods of the BET and SEM, and the adsorption characteristics of modified activated alumina were further studied at different contact time, pH values, adsorbent dosage levels and initial phosphorus concentration. Moreover, the equilibrium adsorption data for phosphorus were better fitted to Langmuir adsorption isotherm, and it means that the uptake of phosphorus preferably followed the monolayer adsorption process.

scholarly journals Adsorptive removal of Ni2+ and Cd2+ from wastewater using a green longan hull adsorbent

2017 ◽  
Vol 36 (1-2) ◽  
pp. 762-773 ◽  
Author(s):  
Xingmei Guo ◽  
Sihan Tang ◽  
Yan Song ◽  
Junmin Nan
Keyword(s):  
Metal Ions ◽  
Adsorption Capacity ◽  
Adsorption Mechanism ◽  
Maximum Adsorption Capacity ◽  
Adsorptive Removal ◽  
Langmuir Adsorption ◽  
Monolayer Adsorption ◽  
Pseudo Second Order ◽  
Adsorptive Mechanism ◽  
Optimized Conditions

The adsorptive removal of Ni2+ and Cd2+ at concentrations of approximately 50 mg L−1 in wastewater is investigated using an agricultural adsorbent, longan hull, and the adsorptive mechanism is characterized. The maximum adsorption capacity of approximately 4.19 mg g−1 Cd2+ was obtained under the optimized conditions of room temperature, pH 5.0, and a solid-to-liquid ratio of 1:30 in approximately 15 min. For Ni2+, the maximum adsorption capacity of approximately 3.96 mg g−1 was obtained at pH 4.7 in approximately 20 min. The adsorption kinetics for both metal ions on the longan hull can be described by a pseudo second-order rate model and are well fitted to the Langmuir adsorption isotherm. The adsorption mechanism of the longan hull to Ni2+ and Cd2+ ions is shown to be a monolayer adsorption of metal ions onto the absorbent surface. Thereinto, the longan hull adsorbent contains N–H, C–H, C=O, and C=C functional groups that can form ligands when loaded with Ni2+ and Cd2+, which reduces the fluorescence of the dried longan hull material.

Bisphenol S adsorption with activated carbon prepared from corncob: optimization using response surface methodology

2020 ◽  
Vol 18 (4) ◽  
Author(s):  
Xiangyang Zhang ◽  
Xiuli Han ◽  
Chun Chang ◽  
Pan Li ◽  
Hongwei Li ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Activated Carbon ◽  
Response Surface ◽  
Adsorption Process ◽  
Order Kinetic ◽  
Bisphenol S ◽  
Monolayer Adsorption ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Parameters Analysis

AbstractActivated carbon derived from raw corncob (CCAC), which prepared with steam as the activating agent, was used to adsorb bisphenol S (BPS) from aqueous solution. Characterizations of CCAC were measured by using the Brunauer-Emmett-Teller, scanning electron microscopy, and Fourier transform infrared spectroscopy. Adsorption conditions including initial BPS concentration, contact time, adsorbent dosage and pH were optimized by response surface methodology (RSM). The results show that adsorption equilibrium was well described by the Langmuir and Koble–Corrigan models. The maximum monolayer adsorption capacity of BPS was found to be 617.29 mg g−1 at 298 K. Based on the thermodynamic parameters analysis, the BPS adsorption process was turned out to be spontaneous and exothermic. The adsorption process of BPS was well described by the pseudo-second-order kinetic model. It also found that H-bonding, π–π interaction, and electrostatic interaction were the main mechanisms in the process of BPS adsorption onto the CCAC.

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