Characterisation of a wheat straw cell wall residue by various techniques

Copper Sorption on a Straw Lignin: Experiments and EPR Characterization

“…For copper(II) sorption, we can say, that despite the relatively small density of complexing sites (1.8 sites/nm 2 ) of LS compared with other natural solids such as humic acids (around 2-5 sites/nm 2 ), the Cu(II) loading capacity (4.2 mg g −1 ) is relatively high. Moreover, considering previous results on lignin model compounds (20), a phenolic oxygen coordination mode which probably involved a methoxy group (see Scheme 2) occurred. It has been shown that carboxylic sites are not involved in the complexation.…”

“…The value of the S/G ratio (1.06) is very close to the one found for wheat straw (19) (1.07), which means that the acido-basic treatment did not modify the structure of native lignin. In other respects, we showed in a previous work (20) that guaiacyl and syringyl monomeric units form rather stable complexes with iron(III) cation, which indicates a probable significant sorption of this ion with the LS substrate.…”

Co‐Adsorption of Copper(II) and 3‐Amino‐1,2,4‐triazole at a Water–Natural Macromolecular Compound Interface: Molecular Structure from Adsorption Isotherms Combined with X‐ray Absorption Measurements

“…The LS was extracted from wheat straw by two successive acid-base treatments, [24] and was fully characterized. [28] Protometric: Potentiometric titrations were carried out as described previously. [29] Briefly, they were performed with a Metrohm 665 Dosimat and a Metrohm 654 pH-meter.…”

Molecular Scale Speciation of First‐Row Transition Elements Bound to Ligneous Material by Using X‐ray Absorption Spectroscopy

“…[28] Such steric hindrance would affect the ability of the ligand to transfer charge to the metal when core electrons are removed in 1s 3 4p z transitions. This also allowed us to conclude that copper(ii) is held in an innersphere complex, as previously seen for other SOM copper complexes.…”

“…[28] The content of acidic surface sites was estimated by using ion exchange reactions and potentiometric titrations in aqueous and non-aqueous media. We determined a concentration of 0.09 Â 10 À3 and 0.48 Â 10 À3 mol g À1 for carboxylic and phenolic moieties, respectively.…”