Abstract The environmental pollution due to the industrial wastewater of four different areas in the Gulf of Suez, Red Sea, Egypt, was studied. Adsorption capacities toward the concerned heavy metal ions Cu(II), Zn(II), Fe(II), and Pb(II) by multiwalled carbon nanotubes (MWCNTs) and modified-MWCNTs with 5,7-dinitro-8-quinolinol were investigated. MWCNTs as well as the modified-MWCNTs were characterized using Fourier transform infrared (FTIR), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). Adsorption of the studied divalent metal ions was measured by atomic absorption spectrometry (AAS). The effects of solution conditions such as pH, shaking time, metal ion concentration, ionic strength and adsorbent dosage on the adsorption process were also examined. The obtained results showed that removals of the heavy metal ions under consideration by MWCNTs are obviously dependent on the experimental conditions. The maximum adsorption capacities as calculated applying Langmuir equation to single ion adsorption isotherms were found to be 142.8 mg/g for Cu(II), 250 mg/g for Zn(II), 111.1 mg/g for Fe(II), and 200 mg/g for Pb(II) using MWCNTs; meanwhile, the modified-MWCNTs exhibited higher values of the respective maximum adsorption capacities as 333.3 mg/g for Cu(II), 500 mg/g for Zn(II), 200 mg/g for Fe(II), and 333.3 mg/g for Pb(II). Kinetic studies were also performed and the experimental data followed a pseudo-second order model of the adsorption process. The obtained results suggest that the tested adsorption systems of MWCNTs and modified-MWCNTs have suitable affinity toward the metal ion under consideration. Both systems could act as potentially applicable tool in environmental protection.

中文翻译：

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用 5,7-二硝基-8-羟基喹啉修饰的碳纳米管作为有效去除工业废水污染物的潜在适用工具

摘要 研究了埃及红海苏伊士湾四个不同地区工业废水对环境的污染。多壁碳纳米管 (MWCNT) 和含有 5,7-二硝基-8-羟基喹啉的改性多壁碳纳米管对相关重金属离子 Cu(II)、Zn(II)、Fe(II) 和 Pb(II) 的吸附能力为调查。使用傅里叶变换红外 (FTIR)、扫描电子显微镜 (SEM) 和透射电子显微镜 (TEM) 对 MWCNT 以及改性 MWCNT 进行表征。所研究的二价金属离子的吸附通过原子吸收光谱法 (AAS) 测量。还研究了溶液条件如 pH 值、振荡时间、金属离子浓度、离子强度和吸附剂用量对吸附过程的影响。所得结果表明，MWCNTs 考虑去除重金属离子显然取决于实验条件。发现将朗缪尔方程应用于单离子吸附等温线计算的最大吸附容量为 Cu(II) 142.8 mg/g、Zn(II) 250 mg/g、Fe(II) 111.1 mg/g 和 200使用 MWCNTs 的 Pb(II) 的 mg/g；同时，改性多壁碳纳米管的最大吸附容量分别为 333.3 mg/g Cu(II)、500 mg/g Zn(II)、200 mg/g Fe(II)和 333.3 mg/g g 为 Pb(II)。还进行了动力学研究，实验数据遵循吸附过程的伪二阶模型。获得的结果表明，所测试的多壁碳纳米管和改性多壁碳纳米管的吸附系统对所考虑的金属离子具有合适的亲和力。这两个系统都可以作为潜在的适用于环境保护的工具。