The invention relates to a preparation method of a soil heavy
metal passivant, and a soil Pb
passivation method. The preparation method comprises the following steps: 1, adding an alkaline solution and sieved
coal ash to a reaction vessel in proportion, carrying out
ultrasonic dispersion stirring to obtain a
slurry, and carrying out a hydrothermal
crystallization reaction through putting the reaction vessel in an oven; and 2, cooling and centrifuging products obtained after the reaction, washing the products with deionized water,
drying,
grinding to obtain synthetic
zeolite powder, burning rice
husk at normal pressure to prepare rice
husk ash, and uniformly mixing
straw powder, the
coal ash, the synthetic
zeolite powder and the rice
husk ash according to weight percentages to obtain the heavy
metal passivant. The
loess farmland soil Pb
passivation effect can be improved through adjusting conditions comprising the
soil pH value, the
soil water content, the passivant quality, the
passivation time, the passivation temperature and the like. The passivation method has the advantages of low cost, simple operation, strong practicality, good safety, and easy popularization, can passivate
soil heavy metals and also can improve the
soil properties, so the passivation method has potential application values in soil heavy
metal pollution restoration.