EDTA改性氮化碳吸附鱼塘中氨氮的性能及应用

宁瑞翔; 廖鑫; 汤日元

doi:10.7671/j.issn.1001-411X.202403001

EDTA改性氮化碳吸附鱼塘中氨氮的性能及应用

Performance and application of EDTA modified carbon nitride in adsorbing ammonia nitrogen in fish ponds

摘要

摘要:
目的制备对鱼塘氨氮有优良吸附性能的氮化碳。
方法通过热缩聚法将三聚氰胺和碳酸氢钠共热制备得到具有基础吸附能力的氮化碳(s−C₃N₄)，并采用乙二胺四乙酸二钠(EDTA−2Na)改性得到改性氮化碳(EDTA−s−C₃N₄)。采用扫描电子显微镜(Scanning electron microscope, SEM)、X射线衍射(X-ray diffraction, XRD)、BET 比表面积、Zeta电位等对材料进行表征。
结果 EDTA−s−C₃N₄的比表面积高达17.7012 m²/g，表面电势为−19 mV，对鱼塘中氨氮有优良的吸附性能，pH=7.5时氨氮去除率达72%。吸附过程符合准二级动力学，Langmuir等温模型拟合估算的最大吸附容量为24.2131 mg/g。EDTA−s−C₃N₄经过5次循环再生后对氨氮的去除率仍达60%。毒性评价表明EDTA−s−C₃N₄对斑马鱼安全无毒。
结论 EDTA−s−C₃N₄对鱼塘中氨氮有优良的清除效果，安全无毒，实用性好。

Abstract:
Objective To prepare modified carbon nitride with enhanced performance in adsorbing ammonia nitrogen in fish ponds.
Method Carbon nitride (s-C₃N₄) with basic adsorption capacity was prepared by co-heating of melamine and sodium bicarbonate using the thermal condensation method, and then s-C₃N₄ was further modified by disodium ethylene diamine tetraacetic acid (EDTA-2Na) to obtain modified carbon nitride (EDTA-s-C₃N₄). Scanning electron microscope (SEM), X-ray diffraction (XRD), BET surface area, and Zeta potential were used to characterize the materials.
Result The specific surface area of EDTA-s-C₃N₄ was as high as 17.7012 m²/g, and the surface potential was −19 mV. It had excellent adsorption performance for ammonia nitrogen in fish ponds with the removal rate of 72% at pH=7.5. The adsorption process conformed to quasi-second-order kinetics, and the maximum adsorption capacity estimated by Langmuir isothermal model fitting was 24.2131 mg/g. After five cycles of regeneration, EDTA-s-C₃N₄ still had a removal rate of 60% for ammonia nitrogen. The toxicity evaluation proved that EDTA-s-C₃N₄ was safe and non-toxic to zebrafish.
Conclusion EDTA-s-C₃N₄ has good removal effect on ammonia nitrogen in fish ponds. It is safe and non-toxic, and has good practicality.

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