scholarly journals Adsorption Capacity and Mechanism of Expanded Graphite for Polyethylene Glycol and Oils

2010 ◽  
Vol 7 (4) ◽  
pp. 1258-1265 ◽  
Author(s):  
Xiu-Yan Pang
Keyword(s):  
Polyethylene Glycol ◽  
Adsorption Capacity ◽  
Adsorption Mechanism ◽  
Water Solution ◽  
Statistical Significance ◽  
Expanded Graphite ◽  
Sem Analysis ◽  
Type I ◽  
Deviation Analysis ◽  
Adsorption Capacities

Expanded graphite (EG) shows higher adsorption capacity for oils such as salad oil and SD300 oil than polyethylene glycol (PEG) with different MW (4000, 10000, 20000). To illustrate their different adsorption mechanism, adsorption capacities of EG for these pollutants are firstly detected. And then stepwise adsorption for oils is carried out with EG which has been saturated first by PEG with different MW. Then difference between stepwise adsorbance of oil is checked with deviation analysis. Scanning electronic microscopy (SEM) analysis is used to show structure difference of EG adsorbed different adsorbates. It is testified adsorption isotherms of PEG are all type I, PEG molecules lay flat on EG surface and equilibrium adsorbance decrease with the increase of PEG MW. Adsorbance for SD 300 oil and salad oil can reach 131.3 g/g and 127.8 g/g respectively. Deviation analysis for stepwise adsorbance of oil shows no statistical significance. EG saturated firstly by PEG, still has an average adsorption capacity of 98 g/g for SD300 oil and 85 g/g for salad oil and it does not change with the initial PEG concentration. SEM photos illustrate the adsorption of oil on EG is mainly filling. In the adsorption of PEG water solution, there is severe breakage of the V-type pore and shrinkage of the particle.

scholarly journals Competitive Adsorption between Polyethylene Glycol and Acid Brilliant Red on Expanded Graphite

2012 ◽  
Vol 9 (2) ◽  
pp. 839-850
Author(s):  
Xiu-Yan Pang ◽  
Li-Li Zhang
Keyword(s):  
Polyethylene Glycol ◽  
Competitive Adsorption ◽  
Raw Materials ◽  
Physical Adsorption ◽  
Intercalation Compound ◽  
Expanded Graphite ◽  
Single Component ◽  
Type I ◽  
Component System ◽  
Single Component System

Expanded graphite (EG) adsorbent was prepared with graphite as raw materials, potassium permanganate as oxidant, and vitriol as intercalation compound. Polyethylene glycol (PEG) 10000 and Acid brilliant red 3B (ABR) with obvious difference in molecular weights were selected as organic adsorbates, and their adsorption and competitive adsorption thermodynamics and kinetics on EG were investigated. The results are: In both single component system and dual component system, the adsorption and competitive adsorption isotherm of PEG 10000 and ABR on EG are all type I. In dual component system, the existence of another component would decrease the single component adsorbance, which might be caused by the competitive adsorption of these adsorbates for the same adsorbing site on EG. Adsorption and competitive adsorption are spontaneous, and the increase of ionic strength, temperature and expanded volume of the adsorbent would cause the increase of adsorbance. No matter the single component system or the dual component system, the adsorption kinetics models can all be well described with pseudo second-order model. Adsorption rate increases with the increase of temperature. Physical adsorption is the main action between EG with these adsorbates.

Novel Aragonite CaCO3 Adsorbents: Synthesis, Characterization and CO2 Adsorption

2014 ◽  
Vol 911 ◽  
pp. 415-419
Author(s):  
Nwe Ni Hlaing ◽  
Srimala Sreekantan ◽  
Radzali Othman ◽  
Hirofumi Hinode ◽  
Winarto Kurniawan ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Hydrothermal Method ◽  
Calcium Oxide ◽  
Sem Analysis ◽  
One Dimensional ◽  
Adsorption Capacities

In this paper, one dimensional nanorod CaCO3 adsorbents were synthesized via hydrothermal method by varying the amount of polyacrylamide (PAM). The XRD results indicated that all of the characteristic peaks of synthesized adsorbents were matched well with the aragonite CaCO3 phase. FE-SEM analysis showed one dimensional nanorod structures with diameter of 40 - 70 nm and lengths up to micrometer. TG results exhibited CaCO3 adsorbents synthesized with 0.4 and 0.6 g of polyacrylamide possessed high CO2 adsorption capacities for first carbonation/calcination cycle (0.86 and 0.79 g-CO2/g-sorbent) which were higher than the theoretical CO2 adsorption capacity (0.78 g-CO2/g-sorbent) of calcium oxide based adsorbents.

Adsorption capacity of bone char for removing fluoride from water solution. Role of hydroxyapatite content, adsorption mechanism and competing anions

2014 ◽  
Vol 20 (6) ◽  
pp. 4014-4021 ◽  
Author(s):  
N.A. Medellin-Castillo ◽  
R. Leyva-Ramos ◽  
E. Padilla-Ortega ◽  
R. Ocampo Perez ◽  
J.V. Flores-Cano ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Adsorption Mechanism ◽  
Water Solution ◽  
Bone Char ◽  
Competing Anions

scholarly journals Single Adsorption of Diclofenac and Ronidazole from Aqueous Solution on Commercial Activated Carbons: Effect of Chemical and Textural Properties

2021 ◽  
Author(s):  
Adriana I. Moral-Rodríguez ◽  
Roberto Leyva-Ramos ◽  
Esmeralda Mendoza-Mendoza ◽  
Paola Elizabeth Díaz-Flores ◽  
Damarys H. Carrales-Alvarado ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Electrostatic Interactions ◽  
Adsorption Mechanism ◽  
Activated Carbons ◽  
Water Solution ◽  
Textural Properties ◽  
Physicochemical Characteristics ◽  
Acidic Site ◽  
Π Stacking ◽  
Acidic Sites

Abstract The importance of the textural and physicochemical characteristics upon the adsorption capacity of the commercial activated carbons (ACs) Coconut, Wood, Merck, Darco and Norit towards ronidazole (RNZ) and diclofenac (DCF) from water solution was investigated thoroughly in this work. At pH = 7, Coconut AC and Wood AC presented the highest adsorption capacity towards RNZ (444 mg/g) and DCF (405 mg/g), correspondingly. The maximum mass of RNZ adsorbed onto Coconut AC was higher in this study than those outlined previously in other works. Besides, the maximum capacity of Wood AC for adsorbing DCF was comparable to those found for other ACs. The findings disclosed that the adsorption capacity of all the ACs was remarkably increased by surface area and was favored by incrementing the acidic site concentration. The π-π stacking interactions were the predominant adsorption mechanism for the RNZ and DCF adsorption on ACs, and the acidic sites favored the adsorption capacity by activating the π-π stacking. Electrostatic interactions did not influence the adsorption of RNZ on Coconut AC, but electrostatic repulsion decreased that of DCF on Wood AC. In the range of 15–25°C, the adsorption of RNZ and DCF on the Coconut and Wood ACs was endothermic, but the capacity remained essentially constant by elevating the temperature from 25 to 35°C.

Synthesis of Expanded Graphite: Effect of the graphite flake size on adsorption capacities to Methylene Blue

2021 ◽  
Vol 10 (3) ◽  
pp. xx-xx
Author(s):  
Chien Hoang Thi ◽  
Ly Vu Thi Huong ◽  
Thao Tran Thi ◽  
Thuy Vu Thi ◽  
Ngan Nguyen Thi ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Specific Surface ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Specific Surface Area ◽  
Expanded Graphite ◽  
Graphite Flake ◽  
Adsorption Capacities ◽  
First Time

For the first time, the expansion grade of graphite was studied through the effect of the flake size. The result shown the larger flake size exhibits a higher expansion grade.  In addition, the more expanded material, the higher specific surface area can be obtained. The synthesized expanded graphites were used for the adsorption of methylene blue. The expanded graphite with the highest expansion grade displayed the highest adsorption capacity due to its specific surface area.

scholarly journals Evaluation of Polyethylene Glycol Crosslinked β-CD Polymers for the Removal of Methylene Blue

2020 ◽  
Vol 10 (13) ◽  
pp. 4679
Author(s):  
Isabelle Mallard ◽  
David Landy ◽  
Sophie Fourmentin
Keyword(s):  
Methylene Blue ◽  
Polyethylene Glycol ◽  
Adsorption Mechanism ◽  
Soxhlet Extraction ◽  
Diglycidyl Ether ◽  
Adsorption Properties ◽  
Crosslinking Reaction ◽  
Optimal Conditions ◽  
Adsorption Capacities ◽  
Crosslinking Agents

The environment is at the heart of global worldwide discussion. This study describes the synthesis of ecofriendly polymers by a crosslinking reaction between β-cyclodextrin as the monomer and polyethylene glycol diglycidyl ether (PEDGE) as well as ethylene diglycidyl ether (EDGE) as the crosslinking agents. The studied polymers were characterized by several techniques, such as SEM, FTIR, TGA-TDA and XRD. Their adsorption properties for methylene blue under various conditions of pH, contact time and initial concentration of dye were assessed in order to find the optimal conditions. The results indicate that the polymers are good nominates for methylene blue adsorption with adsorption capacities up to 15 mg/g. The adsorption mechanism was demonstrated to follow the Langmuir model. Finally, the regeneration of the polymers was investigated using Soxhlet extraction with ethanol. The absorption capacities of the adsorbent were stable after three cycles.

scholarly journals Adsorption of Copper Ions by Microwave Treated Bentonite

2020 ◽  
Vol 21 (3) ◽  
pp. 537-544
Author(s):  
K. Stepova ◽  
L. Sysa ◽  
A. Kontsur ◽  
O. Myakush
Keyword(s):  
Adsorption Mechanism ◽  
Copper Ions ◽  
Sem Analysis ◽  
Copper Compound ◽  
Concentrated Solutions ◽  
Freundlich Model ◽  
Eds Analysis ◽  
Adsorption Capacities ◽  
Enhanced Adsorption ◽  
Co Precipitation

Changes of bentonite surface structure under the influence of direct microwave irradiation during adsorpion of Cu2+ from concentrated solutions were investigated by X-ray and EDS analysis. The microwave treated bentonite (MTB) has been proved to have enhanced adsorption capacity for copper due to improved pore structure and some peculiarities of adsorption mechanism. The non-linear fitting of experimental data to the theoretical isotherms have demonstrated that the adsorption on natural bentonite fitted the Toth model, whilst microwave-treated bentonite fitted the Langmur-Freundlich model. The isotherm modeling allowed predicting the maximal adsorption capacities 44.8 mg/g. XRD and SEM analysis of MTB sample after adsorption indicated formation of microcrystals of individual copper compound. The adsorption on MTB sample takes place not only in pores or in monomolecular layer on the bentonite surface, but the prevalent mechanism is surface-induced co-precipitation of copper as microcrystals of individual copper compound.

scholarly journals Linkage Disequilibrium in Domestic Sheep

Genetics ◽  
2002 ◽  
Vol 160 (3) ◽  
pp. 1113-1122
Author(s):  
A F McRae ◽  
J C McEwan ◽  
K G Dodds ◽  
T Wilson ◽  
A M Crawford ◽  
...  
Keyword(s):  
Linkage Disequilibrium ◽  
Type I Error ◽  
Statistical Significance ◽  
Domestic Sheep ◽  
Type I ◽  
Single Nucleotide ◽  
Microsatellite Genotype ◽  
Marker Distance ◽  
The Relationship ◽  
Two Populations

Abstract The last decade has seen a dramatic increase in the number of livestock QTL mapping studies. The next challenge awaiting livestock geneticists is to determine the actual genes responsible for variation of economically important traits. With the advent of high density single nucleotide polymorphism (SNP) maps, it may be possible to fine map genes by exploiting linkage disequilibrium between genes of interest and adjacent markers. However, the extent of linkage disequilibrium (LD) is generally unknown for livestock populations. In this article microsatellite genotype data are used to assess the extent of LD in two populations of domestic sheep. High levels of LD were found to extend for tens of centimorgans and declined as a function of marker distance. However, LD was also frequently observed between unlinked markers. The prospects for LD mapping in livestock appear encouraging provided that type I error can be minimized. Properties of the multiallelic LD coefficient D′ were also explored. D′ was found to be significantly related to marker heterozygosity, although the relationship did not appear to unduly influence the overall conclusions. Of potentially greater concern was the observation that D′ may be skewed when rare alleles are present. It is recommended that the statistical significance of LD is used in conjunction with coefficients such as D′ to determine the true extent of LD.

scholarly journals Effects of Electronegativity and Hydration Energy on the Selective Adsorption of Heavy Metal Ions by Synthetic NaX Zeolite

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4066
Author(s):  
Xianyuan Fan ◽  
Hong Liu ◽  
Emmanuella Anang ◽  
Dajun Ren
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Adsorption Capacity ◽  
Heavy Metal Ions ◽  
Binary Systems ◽  
Adsorption Mechanism ◽  
Selective Adsorption ◽  
Hydration Energy ◽  
Nax Zeolite ◽  
High Electronegativity

The adsorption capacity of synthetic NaX zeolite for Pb2+, Cd2+, Cu2+ and Zn2+ in single and multi-component systems were investigated. The effects of electronegativity and hydration energy on the selective adsorption, as well as potential selective adsorption mechanism of the NaX zeolite for Pb2+, Cd2+, Cu2+ and Zn2+ were also discussed. The maximum adsorption capacity order of the heavy metals in the single system was Pb2+ > Cd2+ > Cu2+ > Zn2+, and this could be related to their hydration energy and electronegativity. The values of the separation factors (α) and affinity constant (KEL) in different binary systems indicated that Pb2+ was preferentially adsorbed, and Zn2+ presented the lowest affinity for NaX zeolite. The selective adsorption capacities of the metals were in the order, Pb2+ > Cd2+ ≈ Cu2+ > Zn2+. The trend for the selective adsorption of NaX zeolite in ternary and quaternary systems was consistent with that in the binary systems. Pb2+ and Cu2+ reduced the stability of the Si-O-Al bonds and the double six-membered rings in the NaX framework, due to the high electronegativity of Pb2+ and Cu2+ than that of Al3+. The selective adsorption mechanism of NaX zeolite for the high electronegative metal ions could mainly result from the negatively charged O in the Si-O-Al structure of the NaX zeolite, hence heavy metal ions with high electronegativity display a strong affinity for the electron cloud of the oxygen atoms in the Si-O-Al. This study could evaluate the application and efficiency of zeolite in separating and recovering certain metal ions from industrial wastewater.

scholarly journals The Singular Molecular Conformation of Humic Acids in Solution Influences Their Ability to Enhance Root Hydraulic Conductivity and Plant Growth

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 3
Author(s):  
Maite Olaetxea ◽  
Veronica Mora ◽  
Roberto Baigorri ◽  
Angel M. Zamarreño ◽  
Jose M. García-Mina
Keyword(s):  
Polyethylene Glycol ◽  
Humic Acid ◽  
Hydraulic Conductivity ◽  
Plant Growth ◽  
Polyacrylic Acid ◽  
Molecular Conformation ◽  
Water Solution ◽  
Biological Effects ◽  
Root Hydraulic Conductivity ◽  
Molecular Systems

Some studies have reported that the capacity of humic substances to improve plant growth is dependent on their ability to increase root hydraulic conductivity. It was proposed that this effect is directly related to the structural conformation in solution of these substances. To study this hypothesis, the effects on root hydraulic conductivity and growth of cucumber plants of a sedimentary humic acid and two polymers—polyacrylic acid and polyethylene glycol—presenting a molecular conformation in water solution different from that of the humic acid have been studied. The results show that whereas the humic acid caused an increase in root hydraulic conductivity and plant growth, both the polyacrylic acid and the polyethylene glycol did not modify plant growth and caused a decrease in root hydraulic conductivity. These results can be explained by the different molecular conformation in water solution of the three molecular systems. The relationships between these biological effects and the molecular conformation of the three molecular systems in water solution are discussed.

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