Hydrated Iron Oxide Embedded to Natural Zeolite: Effect of Nanoparticles and Microparticles on Sorption Properties of Composites

The materials based on natural zeolites are attractive due to a wide spectrum of their functional properties and low lost. In this work, zeolite-based composites containing nanosized particles of hydrated iron oxide (30-50 nm) have been synthesized by means of precipitation of the modifier from citric solution under elevated temperature. The nanoparticles screen small zeolite pores. The particles of micron size have been also deposited inside zeolite under ambient conditions; they are located in macropores. The composites were tested as sorbents and containers for prolonged release of liquid fertilizers. Sorption of a number of inorganic cations from multicomponent solution was carried out. In the case of the composite containing nanoparticles, the removal degree reaches 99 (Pb2+) and 78 (Ca2+), this is higher than that for the pristine zeolite (78 and 56% respectively). Sorption rate of Pb2+ ions is fitted by the model of chemical reaction of pseudo-first order. The nanoparticles accelerate sorption, and the particles of micron size make it slower. Similar effect of embedded particles has been found used for the leakage of the solution containing microcomponents, which are necessary for the plant growth. The sorbents impregnated with this solution were added to soil, and the strongest effect on the development of sprouts of Cucumis sativus has been found for the sorbent containing the particles of micron size. Thus, changing the size of embedded oxide particles, it is possible to affect their functional properties.