- M. Gallet (1)
- D. Gilliland (1)
- J.T.C. Grotenhuis (1)
- A. Haeger (1)
- J.Z. He (1)
- J.P. Knox (1)
- A.A. Koelmans (1)
- L.K. Koopal (1)
- D. Kupryianchyk (1)
- I. Liakos (1)
- F. Liu (1)
- S.J. Lu (1)
- M. Morra (1)
- M.D. Nagel (1)
- M.I. Rakowska (1)
- H.H.M. Rijnaarts (1)
- M. Rodrigues-Valverde (1)
- H.A. Schols (1)
- S. Siboni (1)
- W.F. Tan (1)
- M. Vayssade (1)
- E. Velzenberger (1)
- R.P. Verhoef (1)
- P. Vigneron (1)
- C.D. Volpe (1)
Extraction of sediment-associated polycyclic aromatic hydrocarbons with granular activated carbon
Rakowska, M.I. ; Kupryianchyk, D. ; Grotenhuis, J.T.C. ; Rijnaarts, H.H.M. ; Koelmans, A.A. - \ 2013
Environmental Toxicology and Chemistry 32 (2013)1. - ISSN 0730-7268 - p. 304 - 311.
environmental black carbon - soot-like materials - san-francisco bay - polychlorinated-biphenyls - surface-chemistry - pcb bioavailability - organic-compounds - marine sediment - sorption - adsorption
Addition of activated carbon (AC) to sediments has been proposed as a method to reduce ecotoxicological risks of sediment-bound contaminants. The present study explores the effectiveness of granular AC (GAC) in extracting polycyclic aromatic hydrocarbon (PAH) from highly contaminated sediments. Four candidate GAC materials were screened in terms of PAH extraction efficiency using single-step 24-h GAC extractions, with traditional 24-h Tenax extraction as a reference. Subsequently, sorption of native PAHs to the best performing GAC 1240W (0.45–1.70¿mm) was studied for sediment only and for GAC–sediment mixtures at different GAC–sediment weight ratios, using 76-µm polyoxymethylene (POM) passive samplers. Granular AC sorption parameters for PAHs were determined by subtracting the contribution of PAH sorption to sediment from PAH sorption to the GAC–sediment mixture. It appears that the binding of PAHs and the effectiveness of GAC to reduce sediment porewater concentrations were highly dependent on the GAC–sediment mixing ratio and hydrophobicity of the PAH. Despite the considerable fouling of GAC by organic matter and oil, 50 to 90% of the most available PAH was extracted by the GAC during a 28-d contact time, at a dose as low as 4%, which also is a feasible dose in field-scale applications aimed at cleaning the sediment by GAC addition and removal.
Determination of the point-of-zero, charge of manganese oxides with different methods including an improved salt titration method
Tan, W.F. ; Lu, S.J. ; Liu, F. ; Feng, X.H. ; He, J.Z. ; Koopal, L.K. - \ 2008
Soil Science 173 (2008)4. - ISSN 0038-075X - p. 277 - 286.
isoelectric points - surface-chemistry - oxidation - minerals - interface - soils - ph - birnessite - hydroxides - adsorption
Manganese (Mn) oxides are important components in soils and sediments. Points-of-zero charge (PZC) of three synthetic Mn oxides (birnessite, cryptomelane, and todorokite) were determined by using three classical techniques (potentiometric titration or PT, rapid PT or R-PT, and salt titration or ST) and a modified salt titration method with a prolonged equilibration time (ST method with a prolonged equilibration time [PST]). The same methods have been applied to goethite, which was used as a reference material. The PZC values of goethite obtained by PT and R-PT methods were both 7.95, and those by the ST and PST method were 8.16 and 8.30, respectively, for birnessite cryptomelane, and todorokite. The PT method yielded PZC of 1.18, 1.98, and 3.98, and the RPT method yielded 1.60, 2.11, and 3.47, respectively, for birnessite, cryptomelane, and todorokite. In contrast to goethite, there was no PZC found with the ST method, even when the types and concentrations of the added electrolytes changed. However, when after KCl addition the equilibration time was prolonged 28 h, the PZC of birnessite, cryptomelane, and todorokite could be found and were 0.97, 1.74, and 3.39, respectively. The fact that the normal ST method failed for the Mn oxides is due to their low PZC, because at this low pH value, the oxides may start to dissolve. Compared with PT and RPT methods, the PST method is reliable, simple, and convenient. The PST approach seems also suitable for other similar colloid systems.
Enzymatically-tailored pectins differentially influence the morphology, adhesion, cell cycle progression and survival of fibroblasts
Nagel, M.D. ; Verhoef, R.P. ; Schols, H.A. ; Morra, M. ; Knox, J.P. ; Ceccone, G. ; Volpe, C.D. ; Vigneron, P. ; Bussy, C. ; Gallet, M. ; Velzenberger, E. ; Vayssade, M. ; Cascardo, G. ; Cassinelli, C. ; Haeger, A. ; Gilliland, D. ; Liakos, I. ; Rodrigues-Valverde, M. ; Siboni, S. - \ 2008
Biochimica et Biophysica Acta. General subjects 1780 (2008)7-8. - ISSN 0304-4165 - p. 995 - 1003.
hairy ramified regions - growth-factor receptors - surface-chemistry - fibronectin conformation - arabinogalactan-proteins - monoclonal-antibodies - human keratinocytes - integrin binding - adsorbed fibronectin - rhamnogalacturonan-i
Improved biocompatibility and performance of biomedical devices can be achieved through the incorporation of bioactive molecules on device surfaces. Five structurally distinct pectic polysaccharides (modified hairy regions (MHRs)) were obtained by enzymatic liquefaction of apple (MHR-B, MHR-A and MHR-), carrot (MHR-C) and potato (MHR-P) cells. Polystyrene (PS) Petri dishes, aminated by a plasma deposition process, were surface modified by the covalent linking of the MHRs. Results clearly demonstrate that MHR-B induces cell adhesion, proliferation and survival, in contrast to the other MHRs. Moreover, MHR- causes cells to aggregate, decrease proliferation and enter into apoptosis. Cells cultured in standard conditions with 1% soluble MHR-B or MHR- show the opposite behaviour to the one observed on MHR-B and --grafted PS. Fibronectin was similarly adsorbed onto MHR-B and tissue culture polystyrene (TCPS) control, but poorly on MHR-. The Fn cell binding site (RGD sequence) was more accessible on MHR-B than on TCPS control, but poorly on MHR-. The disintegrin echistatin inhibited fibroblast adhesion and spreading on MHR-B-grafted PS, which suggests that MHRs control fibroblast behaviour via serum-adhesive proteins. This study provides a basis for the design of intelligently-tailored biomaterial coatings able to induce specific cell functions.