过氧化氢增氧水的理化特性及其在黏土中入渗分析

    Physicochemical properties of hydrogen peroxide aerated water and its infiltration in clays

    • 摘要: 地下滴灌的黏土通常伴随着缺氧的特征。过氧化氢增氧灌溉是改善土壤通气性的有效方法。为探讨添加过氧化氢对水的理化特性及其在土壤中入渗的影响,该研究分析了不同浓度的过氧化氢增氧水(H2O2浓度分别为0、600、800、1 000 mg/L)的溶解氧浓度、氧气传质系数、表面张力系数、电导率和pH值以及入渗过程。结果表明:溶解氧浓度随H2O2添加浓度的增大而增大,表面张力系数则呈现出相反的趋势。溶解氧浓度与表面张力系数存在良好的对数函数关系,二者可以作为过氧化氢增氧水理化特性的定量评价指标。与对照相比,过氧化氢增氧水促进了土壤水分入渗过程,提高了土壤的持水能力。土壤累积入渗量、湿润锋深度以及土壤含水率均随H2O2浓度的增加先上升后下降,最大值在800 mg/L处理中获得。Philip入渗模型能够较好地模拟过氧化氢增氧水的入渗过程,吸渗率随H2O2浓度的增加先上升后下降,最大值出现在800 mg/L处理。吸渗率与溶解氧浓度之间存在良好的二次多项式关系。在该试验条件下推荐800 mg/L的H2O2添加浓度为最优浓度。研究结果为过氧化氢增氧水的实际应用提供科学依据,为土壤通气性高效调控提供理论指导。

       

      Abstract: Clay soils with subsurface drip irrigation are often characterized by hypoxia. The addition of hydrogen peroxide to water to produce hydrogen peroxide oxygenated water, which is delivered to the root zone of crops via a subsurface drip irrigation system to increase soil oxygen levels, is a promising method of alleviating oxygen deprivation in the root zone. To explore the variation of dissolved oxygen concentration, oxygen transfer coefficient, surface tension coefficient, electrical conductivity and pH value with different hydrogen peroxide oxygenated water concentrations (H0-0 mg/L; H1-600 mg/L; H2-800 mg/L; and H3-1 000 mg/L), as well as the response of cumulative infiltration, depth of the wetting front and soil water content to hydrogen peroxide oxygenated water concentrations, two trials were carried out in 2021 at the State Key Laboratory of Eco-hydraulics in Northwest Arid Region at Xi'an University of Technology, China. The results of the study showed that H2O2 significantly increased the concentration of dissolved oxygen in water and the concentration of dissolved oxygen increased with increasing concentration of H2O2 added. Dissolved oxygen concentration was significantly enhanced by 52.10%, 87.11% and 126.59% in H1 to H3 treatments, respectively, as compared to the H0 treatment. The increase in H2O2 concentration decreased the oxygen transfer coefficient and inhibited the oxygen transfer process. Oxygen transfer coefficient was significantly increased by 65.17% in the H1 treatment as compared to the H3. The surface tension coefficient decreased significantly with increasing H2O2 concentration. The surface tension coefficients in H1 to H3 treatments were significantly reduced by 17.72%, 23.57% and 31.60%, respectively, compared to the H0 treatment. Electrical conductivity showed an increasing trend with increasing concentration of H2O2 addition, but the difference between H0 and H1 treatments was not significant (P>0.05). Electrical conductivity was significantly higher in H2 and H3 treatments by 6.60% and 10.42%, respectively, as compared to the H0. The change in pH showed an opposite trend to electrical conductivity, with pH showing a decreasing trend with increasing concentration of H2O2 added. There was a good logarithmic function relationship between dissolved oxygen concentration and surface tension coefficient, and the two could be used as a quantitative evaluation indicator of the physicochemical properties of hydrogen peroxide oxygenated water. Compared to the control, hydrogen peroxide oxygenated water facilitated the process of soil water infiltration and increased the water holding capacity of the soil. The cumulative infiltration showed a trend of increasing and then decreasing with increasing H2O2 addition concentration. Cumulative infiltration was significantly increased by 14.50%, 29.98% and 16.64% for H1 to H3 treatments, respectively, compared to the H0 treatment. For the same infiltration time, the depth of the wetting front showed a tendency of increasing and then decreasing with the increase of H2O2 addition concentration. The depth of wetted fronts was significantly increased by 7.66%, 18.84% and 13.39% in H1 to H3 treatments, respectively, compared to the H0. The soil water content was significantly increased by 8.73% and 4.23% in H2 and H3 treatments, respectively, as compared to the H0. The Philip infiltration model was able to better simulate the infiltration process of hydrogen peroxide oxygenated water, and the soil sorptivity showed a tendency of increasing and then decreasing with the increase of the added concentration of H2O2, with the maximum value also appeared in the treatment of 800 mg/L. There was a good quadratic polynomial relationship between the soil sorptivity and the dissolved oxygen concentration. Considering the results of the study together, the recommended concentration of 800 mg/L of H2O2 was the optimal concentration under the test conditions. These results could provide a scientific foundation for the practical application of hydrogen peroxide oxygenated water and a theoretical guide for the efficient regulation of soil aeration.

       

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