Preparation method of composite hydrated iron oxide

The invention discloses a preparation method of composite hydrated iron oxide, and the method comprises the following steps: step (1): adding a weak alkaline solution to a ferrous chloride crystal solution until the pH value is 4-6, and curing; and step (2): after the curing, continuously adding a sodium carbonate solution until the pH value is 6-8, filtering and drying to obtain the hydrated ironoxide. The method uses ferrous iron and an alkali to prepare the composite hydrated iron oxide comprising alpha-FeOOH and gamma-FeOOH. The hydrated iron oxide has much higher adsorbability to heavy metals in water than a single hydrated iron oxide. 本发明公开了一种复合水合氧化铁的制备方法，包括以下步骤：步骤(1)：往氯化亚铁晶体溶解中加入弱碱性溶液至ph为4-6，进行熟化；步骤(2)：熟化后，继续加入碳酸钠溶液至ph为6-8，过滤，烘干，得到水合氧化铁，本发明利用亚铁和碱制备一种由ɑ-FeOOH和γ-FeOOH组成的复合水合氧化铁。这种水合氧化铁对水中重金属的吸附性远高于单一的水合氧化铁。