Kinetics of Nano-zinc Oxide in Desert Calcareous Soils

Abstract

A laboratory experiment was carried out to study the kinetics reaction of zinc added to calcareous soils from different fertilizer sources and extracted by DTPA solution. Where two types of fertilizers were added, the first, nano-zinc fertilizers in the form of nano-metallic zinc oxide (ZnnO), nano-chelated zinc (ZnnDTPA), and nano-zinc humate (ZnnHA), while the second type was the same fertilizer sources, but in their regular form (ZnO, ZnDTPA and ZnHA). All of them were added at a concentration of 100 mg kg-1 and the nano and regular zinc sources were incubated after they were added to the soil to know their physical and chemical behavior during different incubation periods of 0, 5, 10, 20, 40, 80, 120 and 160 days, with two replications for each incubation period. After the end of each period, zinc was extracted by DTPA, and the data of extracted zinc were subjected to five kinetic equations to reach the best equation describing the behavior of zinc release. The results showed a rapid decrease in the concentration of zinc extracted at the incubation period of 0 days for all fertilizer sources and the continuation of the decrease in concentration with the length of the incubation period gradually until the end of the period after 160 days. The percentage of decrease in nano-zinc fertilizer was less than that of regular fertilizers. The ZnnDTPA chelated zinc source was superior among the regular and nano fertilizer in giving the highest concentration of zinc throughout the incubation period. The second-order equation was the most efficient in describing the behavior and reaction of zinc kinetics in soil from its different sources. The behavior and kinetics reaction of zinc in soil from its different sources.