The present research describes the successful preparation of melon peel biochar modified with CoFe₂O₄ (MPBC/CoFe₂O₄) followed by its usage as a new sorbent to separate, preconcentrate, and determine the toxic heavy metal ions by magnetic solid-phase extraction. The metal ion desorption was performed by 0.1 M HCl solution with a volume of 5.0 mL. Flame atomic absorption spectrometry (FAAS) was utilized for detection of the analyte levels. SEM–EDX, TEM, XRD, and FTIR techniques were carried out to illuminate the structure of MPBC/CoFe₂O₄. The fundamental variables affecting the adsorption and elution efficiencies of the analyte ions including solution pH, MPBC/CoFe₂O₄ amount, type and concentration of eluent, adsorption and desorption equilibrium time, and sample volume were optimized. The detection limits were calculated as 0.41, 1.82, and 3.16 µg L⁻¹ for Cu²⁺, Cd²⁺, and Pb²⁺ ions, respectively, with the relative standard deviation of lower than 4.2%. There were no substantial interference effects on the analyte ion recovery due to the presence of foreign ions at high levels. Five minutes of contact time was adequate to attain the adsorption equilibrium. The adsorption capacity of MPBC/CoFe₂O₄ was obtained as 106.4, 65.4, and 188.7 mg g⁻¹ for Cu²⁺, Cd²⁺, and Pb²⁺ ions, respectively, by utilizing Langmuir isotherm model. The pseudo-second order model is favorable to identify the adsorption kinetics. The method was validated by spike/recovery test, and then, it was successfully implemented to determine the aforementioned analyte levels in sea and stream water, pepper, black cabbage, eggplant, and tomato samples.

本研究介绍了成功制备 CoFe ₂ O ₄修饰的瓜皮生物炭（MPBC/CoFe ₂ O ₄），并将其用作一种新型吸附剂，通过磁性固相分离、预浓缩和测定有毒重金属离子。萃取。金属离子解吸采用0.1 M HCl溶液，体积为5.0 mL。火焰原子吸收光谱法 (FAAS) 用于检测分析物水平。使用 SEM-EDX、TEM、XRD 和 FTIR 技术来阐明 MPBC/CoFe ₂ O ₄的结构。影响分析物离子吸附和洗脱效率的基本变量，包括溶液 pH、MPBC/CoFe ₂优化了O ₄用量、洗脱液类型和浓度、吸附和解吸平衡时间以及样品体积。Cu ²⁺、Cd ²⁺和Pb ²⁺离子的检测限分别计算为0.41、1.82和3.16 µg L ^-1，相对标准偏差低于4.2%。由于存在高水平的外来离子，因此对分析物离子的回收率没有实质性的干扰影响。五分钟的接触时间足以达到吸附平衡。MPBC/CoFe ₂ O ₄对Cu ²⁺、Cd ²⁺的吸附容量分别为106.4、65.4和188.7 mg g ^-1和 Pb ²⁺离子，分别通过利用朗缪尔等温线模型。伪二级模型有利于识别吸附动力学。该方法通过加标/回收试验验证，然后成功地用于测定海水和溪流、胡椒、黑卷心菜、茄子和番茄样品中的上述分析物水平。