Dissolution kinetics of soil clays in sulfuric acid solutions: Ionic strength and temperature effects

A nano-scale study of the mechanisms of non-exchangeable potassium release from micas

“…2), previous laboratory studies of single mineral phyllosilicate dissolution in acidic solutions showed that only the curled sheets have been transformed into a nearly pure silica phase, and analyses done around or inside the corroded zone do not show such depletion of Mg, Fe, Al and K (Turpault and Trotignon, 1994). Thus, the dissolution of micas was limited by Si release (Bibi et al, 2014;Rozalen et al, 2014;Turpault and Trotignon, 1994).…”

“…Previous studies have suggested that mica dissolution rates vary as a function of pH and temperature. Dissolution rates increase in decreasing pH and increasing temperature under acid conditions, with the lowest values being observed near neutral pH, and increasing values being observed with increasing pH (Bibi et al, 2014;Li et al, 2014;Nagy, 1995). The pH of farm soil generally ranges from 4 to 8 may result in lower dissolution rate of micas in soil horizon than in 1 M boiling HNO 3 and 2 M hot HCl used for extraction.…”

“…In addition, the adsorbed H 3 O + ions might breakdown the Al-O bonds. Therefore, the element Al was changed and expelled from the micas structure (Bibi et al, 2014;Köhler et al, 2003). As a result, a Si-rich residual phase was likely to form at the surface of the micas.…”

Chromate adsorption on selected soil minerals: Surface complexation modeling coupled with spectroscopic investigation

“…However, even the TLM model cannot adequately capture the shape of the adsorption edges and it underestimates the Cr(VI) adsorption mainly at higher Cr concentrations and above pH 5. One of the causes of this trend might be the failure to include the effect of clay minerals dissolution ( Figure S4), which is pronounced under both acidic and alkaline conditions [61][62][63]. In addition, the partial dissolution of birnessite releasing Mn 2+ ions in systems with lower ionic strengths at pH > 7…”

A new grading system for plant-available potassium using exhaustive cropping techniques combined with chemical analyses of soils

“…The release of K from layered silicates is a diffusion-controlled reaction under neutral conditions15161718, although both diffusion-controlled reactions and structural decomposition can occur under acid conditions1920. Some researchers have described the release of K by equations containing three simultaneous rate terms212223, which can be divided graphically into simultaneous rates of K release from the surface of the soil complex, the weathered periphery, and the micaceous matrix.…”