Interaction of poly(acrylic acid) and aluminum oxide particles in suspension: Particle size effect.

Graphical abstract Abstract Flocculation is a widely used method to treat wastewater effluents. Aluminum oxide particles have been recognized as major parts of effluents of ceramic industries. In this work, the flocculation of aluminum oxide particles with various sizes (0.06-0.6 μm) was analyzed using poly(acrylic acid) (PAA) to investigate how the flocculation effectiveness of PAA would be affected by the particle size of aluminum oxides. The zeta potential of the suspensions was changed to a similar extent by PAA, regardless of aluminum oxide particle size, implying that the diffuse double layer of the particles was affected in a similar manner despite different adsorption amounts of PAA. The relative turbidity of the suspensions was remarkably reduced for the aluminum oxide with the largest particle size (AL1) and was less affected by aluminum oxide with smaller sizes (AL3). The chord length of the produced flocs was pronouncedly increased by increasing the particle size of aluminum oxide and the floc counts was reduced substantially. The sedimentation studies of the suspensions revealed more efficient sedimentation behavior for AL1/PAA flocs than for AL1 and AL3 based flocs. The settling velocity and sedimentation compactness of the flocs were also analyzed in this study. [ABSTRACT FROM AUTHOR]