Physicochemical sensitivities of tropical peat to electrokinetic environment

Abstract

Tropical peat is unconsolidated superficial deposits with high non-crystalline colloid (humus) content, constituting the subsurface of wetland systems. Laboratory experiments were carried out on a very slightly decomposed fibric and a highly decomposed amorphous, undisturbed tropical peat soils, to determine the physicochemical effects on the peats due to electrokinetic (EK) treatment in terms of mechanisms and resulting effects in the presence of peat water. The different specimens were treated for 3, 6, 12, and 20-day periods. A constant electrical potential of 40 V was applied across the specimens. The untreated and treated specimens were tested for liquid limit (LL), undrained shear strength (Su), water content (WC), zeta potential (ζ), pH, and cation exchange capacity (CEC). The peat water flew from anode to cathode because of the negative charges on the humus. In the vicinity of the anode, the CEC and ζ of the specimens decreased, and the Su and LL of the specimens increased because of the acidic conditions, while alkaline conditions at the cathode had an opposite effect. The sensitivity of the amorphous peat to the EK environment was higher than the sensitivity of the fibric peat to the EK environment because of larger quantities of the colloids and quality of the charges. The acid/base distributions in EK soil processing influenced the soil surface charges, which were fully pH-dependent, resulting in the variations of the CEC and ζ. The ζ variations caused thinning and expanding of the diffuse double layer around the humus particles, and were linked to the flocculation and dispersion of the particles, and subsequently affected the LL and Su of the specimens. The study was found its significance in that it confirmed the relationship between the degree of peat decomposition and the peat sensitivity to the EK treatment.

Adsorptive removal of recalcitrant organic compounds of compost leachate by epichlorohydrin cross‐linked cyclodextrin copolymer

“…This may be attributed to the presence of large amounts of Na + and Cl − ions in the municipal compost leachate. [ 63 ]…”

Electro-Osmotic Consolidation Studies on Peat and Clayey Silt Using Electric Vertical Drain

“…For effective electro-osmotic treatment, the k e required is about 10 -9 m 2 /sV and the k e of clay soils is often in this range. Asadi et al (2010) have reported the k e values of Malaysian peats in the range of 10 -9 -10 -10 m 2 /sV. In field applications, the voltage gradient typically ranges from 10 to \100 V/m (Shang 1998).…”

Stabilization of organic soil using sodium silicate system grout

“…CEC is highly dependent upon organic content and soil texture. The CEC range of soils with a low fibrous content is more than the CEC range of soils with a high fibrous content (Hunter, 1981;Sparks, 1986;Kaya and Yukselen, 2005;Asadi et al, 2009Asadi et al, , 2010Moayedi et al, 2011d. It is reported as milli-equivalents per 100 g of solid (meq/100 g).…”