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Novel sorbents based on silica coated with polyethylenimine (SilPEI) and crosslinked with poly(carboxylic acid) were prepared and characterized. These sorbents are to be used for heavy metal decontamination of aqueous solutions and have to be prepared in easy and ecological ways. A part of the carboxylic moieties [from ethylenediaminetetraacetic acid (EDTA) or citric acid] reacts with some of the amine groups of polyethylenimine, initially coated onto the silica, whereas the other part remains free for further metal complexation. By changing various parameters (temperature, pH, presence or absence of an amide-forming agent), the conditions to prepare the best sorbent—that is, the sorbent exhibiting both a high capacity for metal complexation and good stability in an acidic medium (conditions for metal desorption or stripping)—were defined. The sorbent was prepared by a reaction of 1 g of SilPEI and 1 g of EDTA in water at 0°C, pH 6, during 10 h, using 0.5 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride as a coupling agent. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 799–805, 2003

Polypropylene nonwoven supports carrying α-, β-, and γ-cyclodextrins (CDs) were synthezised. The synthesis consisted of grafting glycidyl methacrylate (GMA) onto the fibers and reacting CDs with epoxide groups in the second step. This article concerns the sorption capacity of these supports toward organic pollutant models of 2-naphtol, 4-nitrophenol, pentachlorophenol, and (2,4-dichlorophenoxy) acetic acid in static (batch) or dynamic (filtration) conditions. The results confirmed that the grafting of CDs onto the supports gave them their specific sorption properties. Besides, it was observed that the best performances were attained when the GMA add-on was in the range of 76–113 % wt and the CD content was 87–118 μmol/g. We also evidenced that the interactions between the organic substrates and the filter occurred through specific interactions with CDs (host–guest inclusion compounds) and that to a lesser extent, nonspecific sorption phenomena also occurred. The data showed that the affinity between the pollutants with three different grafted CDs was not in agreement with the complex formation constants measured in homogeneous systems. Furthermore, the slow kinetics of exchange between the liquid and solid phases was a limiting factor that should prevent the use of the filters at elevated flow rates. At last, the great advantage of these filters is that they could undergo several cycles of use, thanks to intermediate regeneration steps with water–organic solvent mixtures. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1771–1778, 2002

A series of poly(ethylenimines) (PEI) coated onto silica gels has been tested for the ability to complex lead and mercury in aqueous solutions. The study of the kinetics of metal uptake revealed that all sorbents exhibit a fast rate of sorption. The saturation capacities of the different systems were evaluated according to the Langmuir equation. The influence of different parameters like pH, textural characteristics of silica, and amount of coated polymer were discussed. Finally, cycles of stripping and sorption for lead metal were investigated in column system to evaluate the long-term stability of the sorption properties. One striking result was that crosslinking PEI onto silica prevents the desorption of PEI and greatly improves the sorption capacity. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 899–906, 1999

Polyamine [especially poly(ethylenimine) and poly(4-vinylpyridine)] adsorption onto silica gels for chromatography and water-decontamination experiments, using a Raman microprobe, is reviewed. First, the bare silica are characterized. Then, the polyamines and the adsorbed polyamines spectra are compared. We show that polyamine adsorption onto silica occurs with two kinds of polymer populations: chemisorbed (trains due to important interactions between silanol and the nitrogen atom) and physisorbed (multilayers) polymer. The modifications of chemisorbed polymer bands are stronger than are the physisorbed ones. © 1997 John Wiley & Sons, Inc. J Appl Polm Sci 65:871–882, 1997