降雨径流中玉米芯营养素淋出及吸附特性

Nutrients leaching and adsorption properties of corn cob in stormwater runoff

为评估玉米芯作为生物滞留设施中填料土添加剂的可行性,通过理化性质测试、摇床淋出试验、等温吸附试验,与现有添加剂柳木屑、陶粒、稻壳生物炭进行对比,研究玉米芯的理化性质和营养素的淋出及吸附特性。结果表明:玉米芯轻质多孔,具有较大的比表面积和阳离子交换量,其氮磷含量低,有丰富的含氧官能团;以玉米芯作为添加剂,在去离子水的淋洗作用下,氮磷营养素淋出量低、淋出速度快,在降雨径流中氮磷营养素淋出量降低,淋出速度减缓;在营养素质量浓度为2 mg/L的典型降雨径流中,玉米芯可吸附25 mg/kg的NH_(4)^(+)和79 mg/kg的PO_(4)^(3-),相较于其他材料,玉米芯吸附效果突出。玉米芯可作为填料土添加剂用于生物滞留设施中,施用玉米芯可降低填料土营养素淋出风险,提升生物滞留设施对降雨径流中污染物的吸附和去除效果。

To assess the feasibility of corn cob used as an additive material in filler soil,the physicochemical properties and nutrients leaching and adsorption characteristics of corn cob were studied and compared with those of other additive materials,including willow wood,ceramisite,and rice husk biochar,through physicochemical properties tests,leaching experiments,and isothermal adsorption experiments.The results show that corn cob is light and porous,with large specific surface area and high cation exchange capacity,and it has low nitrogen and phosphorus contents,and abundant oxygen-containing functional groups.With corn cob used as additive material,when deionized water was used in leaching experiments,the nitrogen and phosphorus leaching quantities were low,and the leaching speed was fast;the leaching quantities decreased in stormwater runoff leaching experiments,and the leaching speed of nitrogen slowed down.Under the typical stormwater runoff condition with the nutrient mass concentration of 2 mg/L,corn cob adsorbed NH_(4)^(+) of 25 mg/kg and PO_(4)^(3-) of 79 mg/kg,demonstrating its better effect on nutrient adsorption than other additive materials.In conclusion,it is feasible for corn cob to be used as a filler soil additive material in bioretention facilities,which can reduce the nutrients leaching risk from filler soil and improve the effect of bioretention facilities on the removal of pollutants from stormwater runoff.