| Vanadium pollution in soil is an essential environmental problems in China.According to the national soil pollution survey,vanadium in shaanxi province has become a major pollutant and exceeded the standard.Vanadium as a heavy metal has great influence on crops and human health.So how to repair soil vanadium pollution is one of the hot topics in the field of environmental engineering.Vanadium exists in the form of anion.Generally,the soil with negative charge has a low adsorption capacity for vanadate,so how to increase the fixation of vanadium in the soil is also an important issue in environmental science.Biochar can significantly improve the adsorption performance,but most studies are focused on the adsorption and fixation of cations,and there are few studies on the adsorption of anions.Vanadium exists stably as anion in the environment,and the surface modification of biochar can increase the fixation ability of anion.Under anaerobic conditions,the process of dissimilated iron reduction in soil is ubiquitous in nature and is one of the important breathing forms of microorganisms.The iron reduction process of microorganisms in the soil can affect the reduction process of vanadium in the soil,so that vanadium is reduced to the presence form of low chemical combination,so as to reduce the pollution of vanadium and its toxic effect in the soil.Soil texture is one of the factors affecting the reduction process of iron in soil.Therefore,this study selected the respectively collected from some towns in hangzhong soil and ankang in Shanxi Province as sandy and clay in the town of two types of soil,and adopts the cultivation of the rice pot experiment method,through to the soil to add biochar,vanadium,iron oxide and iron oxide modified biochar,discuss the influences of biochar on soil environment,adding iron oxide on soil environment,the influence of the vanadium added pollutants on soil environment,the use of ferric oxide of vanadium pollution repair function,and the use of iron oxide modified biochar vanadium pollution repair function on the soil.The effects of vanadium,ferric oxide and biochar modified with ferric oxide on the microbial community diversity in soil were discussed through the analysis of microbial colony culture and community diversity.The main results obtained are as follows:(1)Vanadium,a heavy metal,can significantly inhibit the growth of rice,and the biomass of rice plants is significantly different in different soils.The clay soil has the potential to mitigate V pollution,while the sandy soil has a low buffer to V pollution.The inhibition rate of sandy soil can reach 55.58%~81.24%,and that of clay soil can reach 31.99%~58.64%.(2)Iron oxide and modified biochar have an obvious ability to repair vanadium contaminated soil and maintain the normal growth rate of rice.Compared with rice plants under the stress of vanadium pollution,the biomass of iron oxide and modified biochar significantly increased,the content of chlorophyll in leaves increased,and the content of malondialdehyde decreased.(3)Iron oxide and modified biochar have different remediation effects in different soils.The remediation rate of iron oxide in sandy soil was up to 45.76%~132.52%,and that in clay soil was up to 31.49%~73.14%.The remediation rate of biochar modified by iron oxide in sandy soil can reach 139.80%~418.51%,and that of clay soil can reach 30.29%~70.03%.The effect of iron oxide and biochar modified by iron oxide on vanadium pollution in clay soil was similar,but the effect of iron oxide modified biochar on vanadium pollution in sandy soil was better.(4)Vanadium pollution can reduce the diversity of soil bacteria.The diversity index of vanadium contaminated soil bacteria was changed by adding iron oxide and modified biochar,which increased the diversity of bacteria in soil.It has the effect of remediation to soil vanadium pollution. |
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