Adsorption of biochars (BC) produced from cash crop residuals is an economical and practical technology for removing nutrients from agricultural runoff. In this study, BC made of orange tree trunks and tea tree twigs from the Laoguanhe Basin were produced and modified by aluminum chloride (Al-modified) and ferric sulfate solutions (Fe-modified) under various pyrolysis temperatures (200°C–600°C) and residence times (2–5 h). All produced and modified BC were further analyzed for their abilities to adsorb ammonia and phosphorus with initial concentrations of 10–40 mg/L and 4–12 mg/L, respectively. Fe-modified Tea Tree BC 2h/400°C showed the highest phosphorus adsorption capacity of 0.56 mg/g. Al-modified Orange Tree BC 3h/500°C showed the best performance for ammonia removal with an adsorption capacity of 1.72 mg/g. FTIR characterization showed that P = O bonds were formed after the adsorption of phosphorus by modified BC, N-H bonds were formed after ammonia adsorption. XPS analysis revealed that the key process of ammonia adsorption was the ion exchange between K⁺ and NH⁺₄. Phosphorus adsorption was related to oxidation and interaction between PO³₄ and Fe³⁺. According to XRD results, ammonia was found in the form of potassium amide, while phosphorus was found in the form of iron hydrogen phosphates. The sorption isotherms showed that the Freundlich equation fits better for phosphorus adsorption, while the Langmuir equation fits better for ammonia adsorption. The simulated runoff infiltration experiment showed that 97.3% of ammonia was removed by Al-modified Orange tree BC 3h/500°C, and 92.9% of phosphorus was removed by Fe-modified Tea tree BC 2h/400°C.

吸附经济作物残渣产生的生物炭（BC）是一种经济实用的技术，可以去除农业径流中的养分。在这项研究中，在不同的热解温度（200°C–600°C）下，通过氯化铝（Al改性）和硫酸铁溶液（Fe改性）生产并改性了由老灌河盆地橘树树干和茶树树枝制成的BC。 C）和停留时间（2–5小时）。进一步分析了所有生产和改性的BC分别以10-40 mg / L和4-12 mg / L的初始浓度吸附氨和磷的能力。铁改性的茶树BC 2h / 400°C表现出最高的磷吸附能力，为0.56 mg / g。Al改性的Orange Tree BC 3h / 500°C表现出最佳的脱氨性能，吸附容量为1.72 mg / g。FTIR表征表明，改性BC吸附磷后形成P = O键，氨吸附后形成NH键。XPS分析表明，氨吸附的关键过程是钾之间的离子交换。⁺和NH ⁺ ₄。磷的吸附与PO ³ ₄和Fe ^3+的氧化及相互作用有关。根据XRD结果，发现氨以酰胺钾的形式出现，而磷以磷酸氢铁的形式出现。吸附等温线表明，Freundlich方程更适合磷吸附，而Langmuir方程更适合氨吸附。模拟的径流入渗实验表明，Al改性的橘树BC 3h / 500°C去除了97.3％的氨，Fe改性的BC 2h / 400°C茶树去除了92.9％的磷。