Adsorption characteristics of polyacetic amino acids onto hydrous γ-Al2O3

Bowers, Alan R.; Huang, Chihpin

doi:10.1016/0021-9797(85)90361-3

Cited by 81 publications

(41 citation statements)

References 18 publications

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“…For example, "r-alumina below the isoelectric point (9.0 in 10 -3 M NaC104, Bowers and Huang, 1985) binds organic molecules by ligand-exchange reactions (Kummert and Stumm, 1980), protonation reactions, and hydrogen-bonding mechanisms (Bowers and Huang, 1985). Anion exchange likely played no role in the binding of PCP to ADL and APM because the adsorption capacities decreased on these two adsorbents as the phenolate concentration increased with increasing pH (cf.…”

Section: Discussionmentioning

confidence: 99%

Modified Clays for the Adsorption of Environmental Toxicants: Binding of Chlorophenols to Pillared, Delaminated, and Hydroxy-Interlayered Smectites

Zielke

1988

Clays and clay miner.

104

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Abstract--Due to their unique polarity, pore-size distribution, and high surface areas, pillared and delaminated clays are potentially useful materials for the adsorption of environmenlal toxicants. To determine their properties for adsorption of chlorinated phenols, alumina-pillared montmorillonite (APM), chromia-pillared montmorillonite (CPM), and alumina-delaminated Laponite (ADL) were reacted with aqueous pentachlorophenol (PCP) solutions in batch equilibrium experiments. An hydroxy-A1 Laponite (HAL) in which the Na + exchange ions were replaced by ions of the type AlI304(OH)(24+x)(H20)(I2 .)(7-• was included in the study. With ADL as the adsorbent, the extent of PCP adsorption increased with decreasing pH, and then became constant at pH _< pKa. Thus, the neutral phenol was preferred over the phenolate form. Binding of neutral PCP at pH 4.7 to all adsorbents never reached saturation values, and the loadings achieved were limited by the water solubility of the adsorbate. Among the pillared and delaminated clays investigated, ADL exhibited the largest capacity for physical adsorption of PCP at pH 4.7. Differences in the PCP binding capacities for APM, CPM, and ADL suggested that adsorption was dependent on the pore structure and surface composition of the modified clay adsorbent, not on surface area alone. HAL exhibited quantitative uptake of PCP at the 8 #mole/g level, indicating that a chemisorption mechanism may operate for PCP binding to this adsorbent. Adsorption of 3-chlorophenol, 3,5-dichlorophenol, and 3,4,5-trichlorophenol by ADL at pH 7.4 increased as the degree of hydrophobicity and chlorination of the phenol increased; hence, the binding capacity was not limited by the molecular size of the adsorbate. In contrast to the adsorption properties observed for pillared, delaminated, and hydroxy-interlayered clays, Na+-montmoriUonite and Na+-Laponite did not adsorb PCP from aqueous solution.

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Section: Discussionmentioning

confidence: 99%

Modified Clays for the Adsorption of Environmental Toxicants: Binding of Chlorophenols to Pillared, Delaminated, and Hydroxy-Interlayered Smectites

Zielke

1988

Clays and clay miner.

104

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“…While monocarboxylic acids exhibit only weak adsorption, increasing the number of carboxylic acid groups leads to increased adsorption (1). Aminocarboxylate compounds which are able to effectively complex Fe(III) or Al(III) in solution such as NTA or EDTA display a strong adsorption onto the respective (hydr)oxide surfaces (2)(3)(4).…”

Section: Introductionmentioning

confidence: 99%

“…Phosphonates are effective complexing agents and contain one or more phosphonate groups -C-PO(OH) 2 . Properties such as high water solubility, the ability to complex metals even at high pH, the ability to prevent scale formation and corrosion (5,6), and good chemical stability make them attractive for use in a variety of industrial applications.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Phosphonates onto the Goethite–Water Interface

Nowack

Stone

1999

Journal of Colloid and Interface Science

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“…A striking contrast in the adsorption characteristics between the three reactants are observed; the adsorption affinity increases with the increasing electron-donor ability in the order hydrogen sulfideoacetaldehydeoammonia. The adsorption of organic compounds onto hydrous oxides and other surfaces has often been attributed to hydrogen-bond formation [17]. A hydrogen bond may form between two functional groups, one serving as a proton donor or Bronsted acidic group and another group serving as an electron donor or Lewis basic group.…”

Section: Adsorption Analysismentioning

confidence: 99%

Kinetic analysis on photocatalytic degradation of gaseous acetaldehyde, ammonia and hydrogen sulfide on nanosized porous TiO₂films

Sopyan¹

2007

Science and Technology of Advanced Materials

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The characteristics of the UV illumination-assisted degradation of gaseous acetaldehyde, hydrogen sulfide, and ammonia on highly active nanostructured-anatase and rutile films were investigated. It was found that the anatase film showed a higher photocatalytic activity than the counterpart did, however, the magnitude of difference in the photocatalytic activity of both films decreased in the order ammonia4acetaldehyde4hydrogen sulfide. To elucidate the reasons for the observation, the adsorption characteristics and the kinetics of photocatalytic degradation of the three reactants on both films were analyzed. The adsorption analysis examined using a simple Langmuir isotherm, showed that adsorbability on both films decreased in the order ammonia4acetaldehyde4hydrogen sulfide, which can be explained in terms of the decreasing electron-donor capacity. Acetaldehyde and ammonia adsorbed more strongly and with higher coverage on anatase film (1.2 and 5.6 molecules/nm 2 , respectively) than on rutile (0.6 and 4.7 molecules/nm 2 , respectively). Conversely, hydrogen sulfide molecules adsorbed more strongly on rutile film (0.7 molecules/nm 2 ) than on anatase (0.4 molecules/nm 2 ). Exposure to UV light illumination brought about the photocatalytic oxidation of the three gases in contact with both TiO 2 films, and the decrease in concentration were measured, and their kinetics are analyzed in terms of the Langmuir-Hinshelwood kinetic model. From the kinetic analysis, it was found that the anatase film showed the photocatalytic activities that were factors of $8 and $5 higher than the rutile film for the degradation of gaseous ammonia and acetaldehyde, respectively. However, the activity was only a factor of $1.5 higher for the photodegradation of hydrogen sulfide. These observations are systematically explained by the charge separation efficiency and the adsorption characteristics of each catalyst as well as by the physical and electrochemical properties of each reactant. r

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Adsorption characteristics of polyacetic amino acids onto hydrous γ-Al2O3

Cited by 81 publications

References 18 publications

Modified Clays for the Adsorption of Environmental Toxicants: Binding of Chlorophenols to Pillared, Delaminated, and Hydroxy-Interlayered Smectites

Modified Clays for the Adsorption of Environmental Toxicants: Binding of Chlorophenols to Pillared, Delaminated, and Hydroxy-Interlayered Smectites

Adsorption of Phosphonates onto the Goethite–Water Interface

Kinetic analysis on photocatalytic degradation of gaseous acetaldehyde, ammonia and hydrogen sulfide on nanosized porous TiO₂films

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Adsorption characteristics of polyacetic amino acids onto hydrous γ-Al2O3

Cited by 81 publications

References 18 publications

Modified Clays for the Adsorption of Environmental Toxicants: Binding of Chlorophenols to Pillared, Delaminated, and Hydroxy-Interlayered Smectites

Modified Clays for the Adsorption of Environmental Toxicants: Binding of Chlorophenols to Pillared, Delaminated, and Hydroxy-Interlayered Smectites

Adsorption of Phosphonates onto the Goethite–Water Interface

Kinetic analysis on photocatalytic degradation of gaseous acetaldehyde, ammonia and hydrogen sulfide on nanosized porous TiO2films

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Product

Resources

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Kinetic analysis on photocatalytic degradation of gaseous acetaldehyde, ammonia and hydrogen sulfide on nanosized porous TiO₂films