Effects Of Weathered Coal Activated By Ultrasonic On Forms Of Arsenic In Soil And Soil Enzyme Activity

Arsenic is one of the most toxic metals, defined as “a known human carcinogen” by the world health organization(WHO) and the U.S. environmental protection agency.Arsenic can go into the soil by the way of atmospheric precipitation, fertilizers, pesticides, sewage irrigation and waste staking. It not only harms the soil quality, but also affects crop safety and security of groundwater. Once encountering arsenic pollution, arsenic(As) can influence soil fertility and crop quality, and further endanges human health through the food chain.Immobilization/stabilization technology is a common arsenic pollution treatment technology.In recent years, the application of weathered coal has caused the attention of scholars,weathering coal organic matter contain massive humus acid and oxygenic functional groups,such as carboxyl, quinonyl, phenolic hydroxyl group, alcoholic hydroxyl group, and so on.Weathered coal is playing a role in repairing heavy mental pollution. This topic discusses to get the best activation condition by using ultrasonic activating weathering coal, and studies the activated weathered coal on soil arsenic forms and the influence of soil enzyme activity,aimed at providing the theory basis for repair of arsenic pollution in soil by applying weathering coal for arsenic pollution area. The main results and conclusions are as follows:(1) Ultrasonic can obviously improve the production of free humic acids in weathered coal, but it is influenced by three factors, such as ultrasonic power, ultrasonic time and water-coal ratio. The content of free humic acids in weathered coal first increases and then decreased with power and water-coal ratio, humic acids yield increase over time, the important influence factor is water coal ratio. Through the experiment, the optimal conditions for ultrasonic activation is: ultrasonic power 500 W, water-coal ratio 8:1, ultrasonic activation time 40 min. In this condition, the weathering coal humic acid content is 8.98%.(2) Conclusions of study that effect of humic acid in weathered coal activated by ultrasonic on form of mercury and total concentrations of mercury: Arsenic in soil morphology mainly the organic combination of state and residual state, while applyingweathered coal amount for 10, 20, 40, 60 g/kg soil, weathered coal can reduce the soil dissolved and exchangeable state, special adsorption state, oxidation state of arsenic, increase organic combination of state and residual state of arsenic. When adding activated weathered coal 60g/kg, the content of dissolved and exchangeable state, special adsorption state, the oxidation state of the As are the lowest, they are lower than those of non activated weathered coal, the content of organic combination and residual state of As are at the highest levels,content are higher than those of non activate weathered coal. The study shows that activate weathered coal can better reduce the mobility of arsenic in soil and biological availability,reduce the biological toxicity of arsenic.(3) Conclusion about the effect of weathered coal activated by ultrasonic on soil enzyme activity: With the increase of concentration of arsenic pollution, soil enzyme activity significantly decreased, arsenic has obvious inhibitory effect on soil enzyme. Add the activation of weathered coal, soil invertase activity increased gradually, and the invertase activity was higher than that of activated weathered coal processing, when added weathered coal activated 60g/kg, alleviate the inhibitory effect of arsenic on soil invertase is the best;Urease activity increased gradually, when the weathered coal amount to 60 g/kg, urease activity slightly decreased, and higher than not activation treatment of weathered coal,activation of weathering coal amount under the condition of 40 g/kg, alleviate the effect of arsenic on soil urease inhibitory effect is best.