Hydrous Fe-Al-Zr oxide composite filled dialysis membrane tubes for phosphate desorption study from acidic soils

Abstract

Phosphorus fixation by different soil components is the main problem making it less available to plants. To approximate this biological measure, a method comprising hydrous Fe-Al-Zr ternary mixed oxide (HFAZO) sorbent filled in dialysis membrane tubes (DMT) was developed. The sorbent (HFAZO), which is composed of Fe (60%), Al (25%) and Zr (15%), was synthesized via impregnation method and characterized by XRD, BET, SEM-EDX, FT-IR and FAAS. Its average crystallite size and surface area were found to be 29.59 nm and 107.53 m2/g, respectively. The phosphate desorption study was conducted on soil samples which received different phosphorous (P) treatments, 0, 50,100 and 150 mg kg−1, for 28 days of desorption time and the phosphate desorption from soil to plant was predicted. The results suggested that the phosphorus treatment and desorption time had significant effect on the amount of desorbed phosphorus. Thus, low (0.71–13.41 mg kg−1) P was desorbed from control and higher (1.87–27.84 mg kg−1) P was desorbed from soils receiving the highest P doze (150 mg kg−1) at all levels of extraction time (1–28 days) for all soil samples. The rate of desorption of P through DMT was found to be 0.0271 hr−1 and was low as compared to other findings which implies the soil samples in this study were highly acidic with high phosphorus fixing property. Generally, the present study attempts to add insight on the potential of this method for assessing phosphate desorption kinetics from acidic soil, relevant for agronomic and environmental advising of phosphate fertilizer application and use.