A comparison study between bioflocculants and PAM for dewatering of ultrafine phyllosilicate clay minerals

Surface interaction between phyllosilicate particles and sustainable polymers in flotation and flocculation

“…Hydrogen bonding between NH 2 and COOH groups of proteins and hydroxyl groups of serpentine and/or electrostatic interaction between the cationic biopolymers and the negatively charged surface of the serpentine edge and Si basal planes at pH 7 contributed to adsorption. 29 Pectin strongly adsorbed on the serpentine surface only at pH 7 and no equilibrium was observed ( Fig. 7c ).…”

“…The mechanism of adsorption of the anionic biopolymers alginic acid, pectin, and lignin is likely charge neutralization and/or hydrogen bonding between C O groups of biopolymers and OH groups of serpentine. 29 …”

“…These results were not surprising because the zeta potential results suggested that pectin would be an effective dispersant at pH 10, where the highly negative surfaces of serpentine, especially the silica and edge faces, and negative charge of the biopolymer would contribute to serpentine dispersion. Carboxyl (COOH) functional groups in the polysaccharide backbones of pectin, alginic acid, and lignin could be ionized into COO − , which would increase the repulsive forces, 29 hence improving Ni grade and recovery. The microflotation results show that floatability of pentlandite depends on the polymer and surface charge of serpentine at pH 10.…”

“…Rapid settling of serpentine in the presence of protamine implies that charge neutralization and hydrogen bonding occur simultaneously. 29 The negative surface charges of carboxyl groups on pectin (p K a < 4) 41 would be attracted to the positively charged Mg basal plane by charge neutralization, resulting in flocculation and settling.…”

“…The zeta potentials of 0.2 wt% serpentine suspensions in the absence (control) and presence of 0.5 wt% (mass of polymer/mass serpentine minerals) polymers ( Table 1 ) (the optimum dosage for biopolymers found by Molaei et al 2022 29 ) at pH 3, 7, 8.5, and 10 were measured in triplicate using a ZetaCompact Z9000 zetameter (CAD Instruments, Les Essarts le roi, France) with 10 mM KCl as the background electrolyte solution.…”