Study of Al(OH)₃−Polyacrylamide-Induced Pelleting Flocculation by Single Molecule Force Spectroscopy

Abstract

A nanocomposite polymer, Al(OH)3-polyacrylamide (Al-PAM) hybrid, was tested as a flocculant. This novel hybrid polymer was found to induce pellet-like floccules, leading to a more effective solid-liquid separation than common polyacrylamide (PAM)-based flocculants. To understand the mechanism of Al-PAM-induced pelleting flocculation, the molecular structure of this hybrid polymer was studied using an atomic force microscope (AFM). The interactions between Al-PAM molecules and a silica surface were measured using single molecule force spectroscopy (SMFS). The Al-PAM molecules were found to have a star-like structure with Al(OH)3 colloidal particles as cores connecting PAM chains. The SMFS results showed a strong attachment of the Al(OH)3 cores to the silica surface with an adhesion force of approximately 1250 pN, in contrast to a weaker adhesion force of only approximately 250 pN for PAM chains on the silica surface. The Al-PAM-induced pelleting flocculation is attributed to its star-like structure.

Study of the strength of flocculated structures of polydispersed coal suspensions

“…The publications, which substantiate the mechanism of destruction of floccules due to shearing stress, have recently appeared [15]. It was calculated, that the destruction of floccules occurs with shearing stress of the order of 1-10 Pa, moreover the strength of aggregates grows with an increase in the dose of the flocculant [16].…”

Polymer aids for settling and filtration of oil sands tailings

“…(3) The star-like structure of Al-PAM (Yang et al, 2004). Compared to linear chain polymers, the star-like structure of Al-PAM enhances accessibility of Al-PAM to clay particles and allows more effective bridging, inducing pelleting flocculation, and facilitating the formation of large mushroom type of flocs (Sun et al, 2008). The clay floccules formed by Al-PAM were larger and denser than those formed by Magnafloc 1011.…”

A new cation‐modified Al‐polyacrylamide flocculant for solid–liquid separation in waste drilling fluid

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