Transport and separation of organic macromolecules in ultrafiltration processes

Kilduff, James E.; Weber, Walter J.

doi:10.1021/es00027a021

Cited by 134 publications

(86 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…We have not observed large changes in watercolumn trace metal partitioning between colloidal and dissolved forms that could have been attributed to salinity changes (Wen et al 1996(Wen et al , 1997b(Wen et al , 1999. Kilduff and Weber (1992) and Logan and Jiang (1990) demonstrated that ionic strength changes would mainly affect lower molecular weight forms with molecular weights in the neighborhood of the molecular weight cutoff of the cartridge, i.e., in our case, 1 kDa.…”

mentioning

confidence: 48%

Comparative bioaccumulation studies of colloidally complexed and free‐ionic heavy metals in juvenile brown shrimp Penaeus aztecus (Crustacea: Decapoda: Penaeidae)

Carvalho¹,

Benfield

Santschi

1999

Limnology & Oceanography

View full text Add to dashboard Cite

A large fraction of the trace metal pool in estuarine and coastal waters is complexed with colloidal-sized macromolecular organic matter. Bioaccumulation and bioavailability studies of trace metals have generally utilized freeionic dissolved metal ions. Consequently, little is known about the uptake and depuration kinetics of the colloidally bound species. Chemical characteristics such as the relative hydrophobicity of these metal-colloid complexes may alter their bioavailability by interfering with or enhancing transport across membrane lipid bilayers. We used radiotracers to compare the bioaccumulation and sites of accumulation of colloidally complexed and free-ionic forms of Ag, Cd, Ba, Fe, Sn, Zn, Co, Hg, and Mn in juvenile brown shrimp Penaeus aztecus. In this paper, we present the results from 14-d uptake and bioaccumulation studies in which shrimp could take up radiotracers only from the water. Our results indicated that the colloidally complexed forms were bioavailable to shrimp. Uptake kinetics appeared to be similar in the two treatments for most metals, although by the end of the uptake study, the wholebody activities of Ba, Sn, and Zn were significantly higher in shrimp exposed to free-ionic metals. While the hepatopancreas appeared to be the site of highest accumulation on a mass-specific basis for both treatments, the total activity level of radiotracer differed between the two treatments. In the colloidally complexed treatment, the majority of total tracer activity was associated with the hepatopancreas while shrimp exposed to free-ionic metals exhibited the highest proportion of total activity in the abdomen. The mechanisms underlying these differences remain to be tested.

show abstract

mentioning

confidence: 48%

Comparative bioaccumulation studies of colloidally complexed and free‐ionic heavy metals in juvenile brown shrimp Penaeus aztecus (Crustacea: Decapoda: Penaeidae)

Carvalho¹,

Benfield

Santschi

1999

Limnology & Oceanography

View full text Add to dashboard Cite

show abstract

“…This may be due to changes in RC with Ž . cf, as discussed by Kilduff and Weber 1992 . If the same trend continues, we would expect 126 mM and 285 mM OC at cfs 20 and cf s 50, respectively Ž .…”

Section: Permeation Coefficient Modelmentioning

confidence: 89%

“…out . The CFF membrane science literature and freshwater CFF studies have long ad-Ž dressed this issue more rigorously Logan and Jiang, 1990;Kilduff and Weber, 1992;Douglas et al, . Ž .…”

Section: Background On Cff Breakthroughmentioning

confidence: 99%

Evaluation of two cross-flow ultrafiltration membranes for isolating marine organic colloids

et al. 1998

View full text Add to dashboard Cite

“…Previous work from this same study demonstrated logarithmic permeation of DOC and Δ 14 C with increasing CF and thus increasing average MW of the retentate solution . These seawater DOC solutions were therefore shown to behave ideally with respect to UF theory [Cheryan, 1998;Kilduff and Weber, 1992] and not affected by membrane fouling, changes in permeation flow rates, or system pressures. Accordingly, the logarithmic permeation of DOC and Δ 14 C may also suggest logarithmic DOC size-age distributions.…”

Section: Doc Molecular Size-age Distribution Ultrafiltration Modelmentioning

confidence: 95%

Pacific carbon cycling constrained by organic matter size, age and composition relationships

et al. 2016

View full text Add to dashboard Cite

Marine dissolved organic carbon (DOC) is a major global carbon reservoir, yet its cycling remains poorly understood. Previous work suggests that DOC molecular size and chemical composition can significantly affect its bioavailability. Thus, DOC size and composition may control DOC cycling and radiocarbon age (via Δ 14 C). Here we show that DOC molecular size is correlated to DOC Δ 14 C in the Pacific Ocean. Our results, based on a series of increasing molecular size fractions from three depths in the Pacific, show increasing DOC Δ 14 C with increasing molecular size. We use a size-age distribution model to predict the DOC and Δ 14 C of ultrafiltered DOC. The model predicts both large and small surface DOC with high Δ 14 C and a narrow range (200-500 Da) of low Δ 14 C DOC. Deep model offsets suggest different size distributions and/or Δ 14 C sources at 670-915 m. Our results suggest that molecular size and composition are linked to DOC reactivity and storage in the ocean.

show abstract

Transport and separation of organic macromolecules in ultrafiltration processes

Cited by 134 publications

References 31 publications

Comparative bioaccumulation studies of colloidally complexed and free‐ionic heavy metals in juvenile brown shrimp Penaeus aztecus (Crustacea: Decapoda: Penaeidae)

Comparative bioaccumulation studies of colloidally complexed and free‐ionic heavy metals in juvenile brown shrimp Penaeus aztecus (Crustacea: Decapoda: Penaeidae)

Evaluation of two cross-flow ultrafiltration membranes for isolating marine organic colloids

Pacific carbon cycling constrained by organic matter size, age and composition relationships

Contact Info

Product

Resources

About