| abstract |
The invention discloses a composite passivation material suitable for arsenic, cadmium and lead polluted rice fields and its application. The preparation method includes the following steps: (1) rice straw preparation; (2) hydroxyapatite suspension preparation; (3) ) Preparation of composite passivation materials; (4) Pyrolysis screening. The composite passivation material of the invention uses crop straw as raw material, and is mixed with hydroxyapatite suspension and iron salt solution through a certain solid-liquid ratio and reaction sequence. Microwave, ultrasonic, mechanical stirring and high-temperature oxygen-limited pyrolysis are used to form composite passivation materials including biochar, hydroxyapatite microspheres and nano-iron. When the composite passivation material prepared by the invention is applied in arsenic, cadmium and lead polluted rice fields, the bioavailability of arsenic, cadmium and lead in the soil can be obviously reduced, the accumulation and transformation of arsenic, cadmium and lead in rice grains can be reduced, and the passivation effect is stable and lasting, and the crops and less negative impact on the environment. |