ABSTRACT

A new organic linker Schiff base (H₂L) derived from 4-aminobenzoic acid and 2-carboxybenzaldehyde has been successfully synthesized and characterized. The synthesized linker Schiff base was designed to be used in preparation of a new cadmium-based metal-organic framework (Cd-MOF) by sonochemical synthesis, and characterized by using Fourier-transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), Brunauer-Emmett-Teller (BET), scanning electron microscope (SEM), energy dispersive X-ray (EDX), and thermal analysis. Under an optimum set of synthesis conditions, uniform cubic crystals with average size 44–69 nm and a Langmuir surface area of 163.461 m²/g were produced within 60–75 min by crystal system orthorhombic. The synthesized Cd-MOF was incorporated as an ionophore in a carbon paste electrode for Cu(II) ion determination in different real water samples. The proposed carbon paste electrode showed a Nernstian slope of 30.15 ± 0.35 mV decade⁻¹ covering a linear range of 1.0 × 10⁻⁷ – 1.0 × 10⁻¹ mol L⁻¹ and the detection limit was 7.5 × 10⁻⁸ mol L⁻¹ with long-time stability of more than two months over pH range of 2.5–6.5 and fast response time of 10 s. The proposed sensor was highly selective for Cu(II) ions. The synthesized Cd-MOF had mesoporous structure and this supported the mechanism of Cu(II) ion successful determination.

摘要

已成功合成并表征了衍生自 4-氨基苯甲酸和 2-羧基苯甲醛的新型有机连接基席夫碱 (H ₂ L)。合成的连接基席夫碱旨在用于通过声化学合成制备新型镉基金属有机骨架 (Cd-MOF)，并通过傅里叶变换红外光谱 (FT-IR)、粉末 X 射线表征衍射 (PXRD)、Brunauer-Emmett-Teller (BET)、扫描电子显微镜 (SEM)、能量色散 X 射线 (EDX) 和热分析。在一组最佳合成条件下，均匀立方晶体的平均尺寸为 44-69 nm，朗缪尔表面积为 163.461 m ²/g 是在 60-75 分钟内由晶体系统斜方晶产生的。将合成的 Cd-MOF 作为离子载体掺入碳糊电极中，用于测定不同实际水样中的 Cu(II) 离子。所提出的碳糊电极显示出 30.15 ± 0.35 mV 十进制^-1的能斯脱斜率，覆盖了 1.0 × 10 ^-7 – 1.0 × 10 ^-1 mol L ^-1的线性范围，检测限为 7.5 × 10 ^-8 mol L ^{- 1}在 2.5-6.5 的 pH 范围内具有超过两个月的长期稳定性和 10 秒的快速响应时间。所提出的传感器对 Cu(II) 离子具有高度选择性。合成的 Cd-MOF 具有介孔结构，这支持了成功测定 Cu(II) 离子的机制。