Smectite flocculation structure modified by Al13 macro-molecules – As revealed by the transmission X-ray microscopy (TXM)

Abstract

The aggregate structure which occurs in aqueous smectitic suspensions is responsible for poor water clarification, difficulties in sludge dewatering and the unusual rheological behaviour of smectite rich soils. These macroscopic properties are dictated by the 3D structural arrangement of smectite finest fraction within flocculated aggregates. Here, we report results from a relatively new technique, transmission X-ray microscopy (TXM), which makes it possible to investigate the internal structure and 3D tomographic reconstruction of the smectite clay aggregates modified by Al(13) Keggin macro-molecule [Al(13)(O)(4)(OH)(24)(H(2)O)(12)](7+). Three different treatment methods were shown resulted in three different micro-structural environments of the resulting flocculation. In case of smectite sample prepared in Methods 1 and 3 particles fall into the primary minimum where Van der Waals forces act between FF oriented smectite flakes and aggregates become approach irreversible flocculation. In case of sample prepared using Method 2, particles contacting by edges (EE) and edge to face (EF) orientation fell into secondary minimum and weak flocculation resulted in severe gelation and formation of the micelle-like texture in fringe superstructure, which was first time observed in smectite based gel.

How the hydro-gel flocculation microstructure changes

“…In NaCl solution, flocs form a spiraling, twisted, long-chained, ribbon-like tubular super-structure in a gelled suspension, which is similar to those described in Zbik et al [28]. As shown in Fig.…”

Why Treatment of the Water Based Clay Slurries are Not Effective; the Microstructural Review

“…All our results advocate [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], the structure building phenomenon within entire suspension may be blame for poor settling and dewatering. All these may be result of high water dielectric constant which polarising clay particles and generating electrostatic charge.…”