PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 6741779

Efficiency of passive sampling by adsorbents.

D W Underhill
View original source ↗Export metadata ↓

Abstract

The efficiency of passive samplers can be influenced strongly by the adsorption isotherm. In this study calculations of sampling efficiency were made in terms of dimensionless variables for adsorption controlled by the Langmuir, Freundlich, and Dubinin-Radushkevich isotherms, respectively. Of particular importance is that for the latter isotherm, which is often followed by activated charcoal for the adsorption of solvent vapors, passive sampling may remain highly efficient until a significant fraction of the capacity of the adsorbent has been utilized.

Explore related subjects

AdsorptionAir Pollutants, OccupationalCharcoalMathematicsModels, TheoreticalSolventsVolatilizationJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

D W Underhill. 1984. Efficiency of passive sampling by adsorbents.. https://doi.org/10.1080/15298668491399839

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2026

Three-dimensional porous nano-hydroxyapatite@gelatin composite as efficient adsorbent for uranyl ion removal from low-level radioactive wastewater.

The contamination of water resources by uranyl (UO22+) ions poses significant environmental and health risks, requiring the development of efficient and sustainable remediation strategies. Adsorption-based techniques have emerged as promising approaches in the field of UO22+ removal, but the design of cost-effective, high-capacity, and environmentally friendly adsorbents remains challenging. In this study, a three-dimensional porous nano-hydroxyapatite@gelatin (nHAP@Ge) composite was synthesized through glutaraldehyde cross-linking, combining the structural stability of Ge with the high uranium affinity of nHAP. The optimized nHAP@Ge, with a nHAP:Ge mass ratio of 1:0.5, exhibited exceptional UO22+ removal efficiency (97 %), along with high adsorption capacity (364.03 mg/g). Systematic characterizations using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) methods revealed that the porous structure and surface functional groups (-OH, Ca2+, and PO43-) of the material synergistically contributed to binding UO22+ species. Furthermore, the incorporation of nHAP into the Ge framework resulted in enhanced thermal stability while significantly improving the UO22+ adsorption performance. This work presents a scalable, eco-friendly, and recyclable strategy for the effective treatment of uranium-contaminated water, with potential applications in nuclear wastewater treatment and environmental remediation.

Adsorption↗
PubMed2007

Dual radiolabeling to study protein adsorption competition in relation with hemocompatibility.

Human fibrinogen (Fg) and albumin (HSA) were labeled with (3)H and (14)C, respectively. Dual counting allowed the adsorbed amount of the two proteins to be determined simultaneously. Single adsorption, adsorption of the two proteins in competition, but also exchange (substitution by molecules of the same nature) and displacement (desorption under the action of the other protein) experiments were performed on two model surfaces, glass and polystyrene (PS), as well as on pure polyvinylchloride (PVC-s) and on PVC from blood bag (PVC-b). As expected, the adsorbed amount of a single protein is higher on a hydrophobic compared to a hydrophilic surface. When the two proteins are adsorbed in competition, they are found in equal proportion on glass, while HSA is twice more abundant than Fg on PS and PVC-s and about six times more abundant on PVC-b. This trend is related to an increase of the water contact angle of the substrates. For PVC-b, the contact angle is affected by the presence of aliphatic components exposed at the extreme surface, as determined by angle-resolved X-ray photoelectron spectroscopy. In exchange and displacement experiments, the first adsorbed molecules remain dominating on PS while they can be removed from glass. Given the known importance of HSA and Fg adsorption for the fate of materials placed in contact with blood, the method described in this paper may be used as a first approach to orient the design of surfaces with improved hemocompatibility.

Adsorption↗
PubMed2007

Effective immobilization of subunit protein in mesoporous silica modified with ethanol.

Ethoxylated FSM-type mesoporous silica (folded-sheet mesoporous material) with a pore diameter of 6.2 nm (FSM6.2) remarkably enhances rigidly of the structure in aqueous solutions. The esterified material could be used successfully as an adsorbent to accommodate subunit protein, methemoglobin (Fe(3+)). Furthermore, methemoglobin (Fe(3+)) in the pores of ethoxy-FSM is maintained a peroxidase activity similar to the native, indicating methemoglobin retains its fore subunit structure in the pores of FSM6.2.

Adsorption↗