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Mechanochemical effects on physicochemical parameters of homoionic smectite

1997; Elsevier BV; Volume: 127; Issue: 1-3 Linguagem: Inglês

10.1016/s0927-7757(97)00105-2

1873-4359

Rosa M. Torres Sánchez,

Electrostatics and Colloid Interactions

According to previous works and using the sensitivity of isoelectric point or point of zero charge (IEP and PZC), determinations by diffusion potential method were performed on a smectite with different homoionic (Na+, K+, Li+, Ca2+ and Al3+) cations which were treated thermally and mechanically, in order to determine the influence of these treatments on the structural parameters. XRD general spectra and d(001) peaks showed that smectite peaks were more affected by mechanical treatment rather than by thermal treatment. Smectites with Ca2+ and Al3+ were affected to a lesser extent in agreement with infrared (i.r.) diagrams. PZC values obtained increased in the order of initial<thermal<mechanical treated samples, raising up to pH around 7 for Na+, K+ and Li+ and pH = 6.0 and 4.8 for Ca2+ and Al3+ samples, respectively. These increases in PZC values agreed with the structural Al3+ release which acted as a mechanical mixture with the residual smectite structure and were confirmed by the disappearance of octahedral Al coordination in the i.r. spectra.