Predictions of Pair Interaction Potentials between Kraft Lignin Macromolecules in Black Liquors by Utilization of a Modified Poisson–Boltzmann Approach

Abstract

In this investigation, a modified Poisson−Boltzmann approach has been used to estimate the mean ion concentration distributions of ionic species present in black liquors around charged kraft lignin macromolecules at industrially relevant conditions. The distributions were utilized to predict the double layer repulsion and, further, predict the overall pair interaction potentials between two kraft lignin macromolecules or particles immersed in the black liquor electrolyte. The properties of softwood black liquors were used as input data to the model. The numerical results predicted the pair interaction potentials to remain repulsive up to salt concentrations of about 2.5 M at pOH 1. The critical coagulation concentration of salt was predicted to decrease as the pOH of the black liquor was increased. The predictions at 65 °C and moderate levels of pOH (3.5) and salt concentration (1.9 M) were found to be in good agreement with previous observations reported in the literature.

Superefficient removal of lignins from papermaking wastewater by polycationic adsorption and direct reuse of wastes: structure–activity relationships and interaction mechanisms

“…1 The pollutants contained in the black liquor account for more than 90% of the total pollutants in papermaking wastewater. [2][3][4] As a complex phenol polymer, lignin is the most difficult pollutant to remove from this waste. [5][6][7][8][9][10][11][12][13] At present, the main methods for the removal of lignins in papermaking wastewater are alkali precipitation, acid precipitation, and flocculation, all of which have achieved some application results.…”

“…Papermaking wastewater, with its high toxicity, high chroma, and high chemical oxygen demand, is one of the largest industrial wastewater discharge sources around the globe 1 . The pollutants contained in the black liquor account for more than 90% of the total pollutants in papermaking wastewater 2–4 . As a complex phenol polymer, lignin is the most difficult pollutant to remove from this waste 5–13 …”

Innovative Sustainable Wood Preservatives From Pulp and Paper Industry Byproduct

“…Recently, a modified Poisson-Boltzmann modelling approach was utilized to study the width of the electric double layer, and the ionic charge distribution of lignin molecules in black liquor. The results suggested a very unstable and heterogeneous charge distribution around the lignin molecules [117]. All of these findings suggest that the heterogeneous chemical structure of the lignin in combination with the experimental variables and the concentration of the lignin in the black liquor will affect the response to pH, making it a highly complex system.…”