Humic acids are one type of natural organic matter and precursors of chloro organic compounds that cause a major problematic issue for water treatment plants. In the present study, Hyperbranched polyethylenimine (HPEI) was grafted onto Fe3O4 nanoparticles for HA adsorption from aqueous solution. Fe3O4@HPEI nanoparticles were characterized via TEM, SEM, FTIR, XRD, VSM, and BET analysis. The effects of various operational parameters including initial HA concentration, pH, adsorbent dose, contact time and ionic strength on the HA removal were assessed. According to the obtained statistical model, the optimal condition was acquired at the initial HA concentration 79 mg/L, adsorbent dose 0.128 g/L, pH 3 and contact time 29 min, which up to 97.27% HA were adsorbed by Fe3O4@HPEI that was close to the predicted result by the model (95.6%) that confirmed the validity of the selected model. The adsorption data were fitted to the pseudo-second-order kinetic and Freundlich isotherm. Thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic. The fabricated Fe3O4@HPEI nanoparticles could be repeatedly utilized as a suitable adsorbent to remove HA from the aqueous environment.

中文翻译：

---

胺功能化的 Fe3O4 纳米粒子与 HPEI 在有效去除水溶液中的腐殖酸中的应用：建模和优化

腐植酸是一种天然有机物和氯有机化合物的前体，是水处理厂面临的主要问题。在本研究中，超支化聚乙烯亚胺 (HPEI) 接枝到 Fe3O4 纳米颗粒上，用于从水溶液中吸附 HA。Fe3O4@HPEI 纳米粒子通过 TEM、SEM、FTIR、XRD、VSM 和 BET 分析进行表征。评估了各种操作参数（包括初始 HA 浓度、pH、吸附剂剂量、接触时间和离子强度）对 HA 去除的影响。根据得到的统计模型，在初始HA浓度79 mg/L、吸附剂剂量0.128 g/L、pH 3和接触时间29 min时获得最佳条件，Fe3O4@HPEI吸附高达97.27%的HA接近模型的预测结果（95. 6%) 证实了所选模型的有效性。吸附数据符合拟二级动力学和 Freundlich 等温线。热力学参数表明吸附过程是自发吸热的。制备的 Fe3O4@HPEI 纳米颗粒可以重复用作合适的吸附剂，从水性环境中去除 HA。