Abstract Chemical fertilizers and pesticides used are currently increasing alongside the human population grew and agriculture spread, resulting in high nitrogen (TN) and phosphorus (TP) contents in farmland soil and the surrounding water-bodies. Fabricating economic but effective metal impregnated biochar, as a sorbent to remove inorganic pollutants from water, is important to prevent eutrophication. In the present work, iron-loaded biochar was prepared by impregnating by FeCl3 and following pyrolyzing at 550 °C. The chemical functional groups, surface morphologies, and internal crystal structures of the Fe-loaded biochar (Fe B) were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction, respectively. Results indicated that the preparing process induced a layer of Fe oxide at the surface of biochar, and changed the surface morphology and internal crystal structure. The FeCl3 content in soaking solution had remarkable effects on pore structure formation, surface morphology features and removal efficiencies of TN and TP from wastewater by biochar. The Langmuir model indicated that 1%-Fe impregnated biochar (B1) and the 10%-Fe impregnated biochar (B10) exhibited maximum adsorption capacity of TN and TP, which reached to more than 14 mg/g for TN and 90 mg/g for TP, respectively. B10 could remove over 85% of TP from artificial wastewater and less than 0.5% of TP was released in desorption experiments. Similarly, B1 could remove 60% of TN while only 1% was released in desorption experiments. B1 and B10 could remove 50% of TN and 80% of TP from the actual agricultural wastewater, respectively. This confirmed that Fe-impregnated biochar could effectively remove inorganic nutrients from wastewater and seal them in the prevention of secondary pollution. The Fe B was characterized by FT-IR and SEM before and after its application as an adsorbent in agricultural wastewater, and results revealed that the removal of TN and TP was primarily attributed to the well-developed pore structure and the Fe oxides fixed on the surface of biochar. Inorganic nitrogen and phosphorus in wastewater are removed by surface complexation, coprecipitation, electrostatic interaction and ion exchange. In conclusion, the present work demonstrated that the Fe B is an effective adsorbent for removing TN and TP pollutants from nutrient-rich wastewaters.

中文翻译：

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FeCl3浸渍生物炭去除水中氮磷污染物

摘要 随着人口的增长和农业的发展，目前化肥和农药的使用量不断增加，导致农田土壤和周围水体中氮（TN）和磷（TP）含量较高。制造经济但有效的金属浸渍生物炭，作为从水中去除无机污染物的吸附剂，对于防止富营养化很重要。在目前的工作中，通过用 FeCl3 浸渍并在 550 °C 下热解制备负载铁的生物炭。分别通过傅里叶变换红外光谱 (FT-IR)、扫描电子显微镜 (SEM) 和 X 射线衍射表征了负载铁的生物炭 (Fe B) 的化学官能团、表面形态和内部晶体结构。结果表明，制备过程在生物炭表面诱导了一层氧化铁，改变了表面形貌和内部晶体结构。浸泡液中FeCl3的含量对生物炭对废水中TN和TP的孔结构形成、表面形貌特征和去除效率有显着影响。Langmuir 模型表明，1%-Fe 浸渍生物炭 (B1) 和 10%-Fe 浸渍生物炭 (B10) 对 TN 和 TP 的吸附能力最大，TN 和 90 mg/g 分别达到 14 mg/g 以上。分别为 TP。B10 可去除人工废水中 85% 以上的 TP，解吸实验中释放的 TP 低于 0.5%。同样，B1 可以去除 60% 的 TN，而在解吸实验中仅释放 1%。B1和B10可以分别去除实际农业废水中50%的TN和80%的TP。这证实了铁浸渍生物炭可以有效地去除废水中的无机养分并将其密封以防止二次污染。Fe B 作为吸附剂在农业废水中应用前后通过 FT-IR 和 SEM 对其进行表征，结果表明 TN 和 TP 的去除主要归因于发达的孔隙结构和固定在吸附剂上的 Fe 氧化物。生物炭的表面。通过表面络合、共沉淀、静电相互作用和离子交换去除废水中的无机氮和磷。总之，目前的工作表明，Fe B 是一种有效的吸附剂，可从富含营养的废水中去除 TN 和 TP 污染物。