Adsorption phosphorus uptake

Lyu S-W, Blum U (1990) Effects of fendic acid, an adelopathic compound, on net P, K, and water uptake by cucumber seeddngs in a split-root system. J Chem Ecol 16 2429-2439 Lyu S-W, Blum U, Gerig TM, O Brien TE (1990) Effects of mixtures of phenolic acids on phosphorus uptake by cucumber seedlings. J Chem Ecol 16 2559-2567 MaMno T, Takahashi Y, Sakurai Y, Nanzyo M (1996) Infiuence of soil chemical properties on adsorption and oxidation of phenodc adds in sod suspension. Soil Sci Plant Nutr 42 867-879... 

Contact of one cm of a 0.025 molar solution of dialkyl phosphite in tetradecane at 403 K (130 C) with one gram of iron powder which had been ball milled under pentane resulted in depletion of the phosphorus in solution, as shown in Fig. 11-9. Reaction as well as adsorption took place, for soluble iron was found in the solutions of di(2-ethyIhexy1), dilauryl and distearyl phosphites. Chromatography of the solutions after contact revealed large quantities of alcohol dibutyl phosphite and di(2-ethylhexyl) phosphite yielded 92-97% of the theoretical amount of alcohol after 24 hours. Hydrolysis of the phosphite esters was ascribed to water adsorbed on the walls of the reaction tube and on the iron powder. Forbes and Battersby [46] postulated that hydrolysis is an important aspect of the mechanism of the additive action of phosphite esters. Oxidation to phosphate by the oxygen of the ambient air is deemed minor maximum augmentation of the oxygen uptake by a 6.5% solution of dibutyl phosphite over that of the tetradecane carrier fluid in the presence of iron was 20%. The easy hydrolysis of phosphites is well known. Partial... 

An adsorption isotherm was constructed from integration of TPD peak desorption features for mass 31 (P) associated with increasing e qposure time to calcium phosphate solution (Figure 8). The rapid uptake of phosphorus that begins at approximately 200 min. is a result of the large desorption feature at 1200 K (55). The rapid rise at early e qposure times is primarify a result of the peak at 950 K and may be considered a result of residual salts accumulated at the sur ce, de ite the rinsing procedure. 

Figure 9 shows several TPD spectra of mass 31 (P) at different exposure times to calcium phosphate solution (55). Phosphorus desorption from alumina riiows broad features from 450-700 K, the residual salt peak at 980 K, and a high tenq>erature feature, vAach occurs between 1400 and 1560 K. Variation in the tenq>erature associated with the high tenq)erature desorption feature may be a result of variations in heating rate or thermocouple placement. Unlike the titania spectra, the large feature at 1200 K is absent. In addition, at least one new feature can be observed at approximately 450-700 K Figure 9b shows the corre onding calcium and potassium desorption features. The ratio of calcium and potassium ions to pho horus is conq)arable, but for longer exposures, this ratio decreases dramatically. For a 30 hr. e q>osure, the calcium and potassium to phosphorus ratios drop to less than 1% of the solution concentration. Integration of several phosphorus desorption ectra provide the data for an adsorption isotherm shown in Figure 8. Onset of rapid uptake of pho hate is observed between 20-25 hr.

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