Self-association and aggregation of kraft lignins via electrolyte and nonionic surfactant regulation: stabilization of lignin particles and effects on filtration

Fritz, Consuelo; Salas, Carlos; Jameel, Hasan; Rojas, Orlando J.

doi:10.3183/npprj-2017-32-04_p572-585_rojas

Cited by 14 publications

(9 citation statements)

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“…The SEKL at pH 3 (i.e., N‐SEKL) showed the highest compatibility with the oil interface with the WCA of 40° and OCA of 50°. The elevated WCA/OCA at pH 3 should be associated with the reduction of electrostatic repulsion, which leads to the dominance of the hydrophobic features of lignin macromolecules …”

Section: Resultsmentioning

confidence: 74%

Pickering/Non‐Pickering Emulsions of Nanostructured Sulfonated Lignin Derivatives

Ghavidel

Fatehi

2020

ChemSusChem

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Sulfoethylated lignin (SEKL) polymeric surfactant and sulfoethylated lignin nanoparticles (N‐SEKL) with a size of 750±50 nm are produced by using a facile green process involving a solvent‐free reaction and acidification‐based fractionation. SEKL forms a liquid‐like conventional emulsion with low viscosity that has temporary stability (5 h) at pH 7. However, N‐SEKL forms a gel‐like, motionless, and ultra‐stable Pickering emulsion through a network of interactions between N‐SEKL particles, which creates steric hindrance among the oil droplets at pH 3. The deposition of SEKL and N‐SEKL on the oil surface is monitored by a using a quartz crystal microbalance. Experimentally, the formation of emulsions at pH 7 is found to be reversible owing to the low adsorption energy ΔE of SEKL on the oil droplet (ΔE≈15 kBT), which is determined with the help of three‐phase contact‐angle measurements. However, the high desorption energy (ΔE≈6.0×105 kBT) of N‐SEKL makes it irreversibly adsorb on the oil droplets. SEKL is too hydrophilic to attach to the oil interface (ΔE≈0) and thus does not facilitate emulsion formation at pH 11. Therefore, it is feasible to apply SEKL for the formulation of Pickering or non‐Pickering emulsions in the form of nanoparticles or polymeric surfactants, depending on the targeted application.

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Section: Resultsmentioning

confidence: 74%

Pickering/Non‐Pickering Emulsions of Nanostructured Sulfonated Lignin Derivatives

Ghavidel

Fatehi

2020

ChemSusChem

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“…The pores in this membrane should therefore be sufficiently large to allow the majority of lignin molecules to pass without any particular hindrance. Nevertheless, Figure 2 c,d show that the fraction of large molecules that passed the RC25 membrane is lower than for RC100 and probably indicates the formation of clusters [ 40 ]. Most of these possible clusters can however pass through the large pores in the RC100 and RC200 membranes.…”

Section: Resultsmentioning

confidence: 99%

Mass Transport of Lignin in Confined Pores

et al. 2022

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A crucial step in the chemical delignification of wood is the transport of lignin fragments into free liquor; this step is believed to be the rate-limiting step. This study has investigated the diffusion of kraft lignin molecules through model cellulose membranes of various pore sizes (1–200 nm) by diffusion cells, where the lignin molecules diffuse from donor to acceptor cells through a membrane, where diffusion rate increases by pore size. UV–vis spectra of the donor solutions showed greater absorbance at higher wavelengths (~450 nm), which was probably induced by scattering due to presence of large molecules/clusters, while acceptor samples passed through small pore membranes did not. The UV–vis spectra of acceptor solutions show a characteristic peak at around 350 nm, which corresponds to ionized conjugated molecules: indicating that a chemical fractionation has occurred. Size exclusion chromatography (SEC) showed a difference in the molecular weight (Mw) distribution between lignin from the donor and acceptor chambers. The results show that small pore sizes enable the diffusion of small individual molecules and hinder the transport of large lignin molecules or possible lignin clusters. This study provides more detail in understanding the mass transfer events of pulping processes.

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“…Self-assembly kinetics of lignins into nano-and microparticles significantly impact the surface chemistry of the constructs. [107][108][109][110] The assembly conditions have been found to significantly affect the homogeneity of the particles distribution, their charges, and their sizes. The two approaches which have been evaluated the most for particle preparation are acid neutralization, or pH-shifting, and solvent-shifting.…”

Section: Technical Ligninsmentioning

confidence: 99%