Al-Faiyz Yasair S S, Gouda Mohamed
Department of Chemistry, Faculty of Science, King Faisal University, P.O. Box 380, Al-Ahsa 31982, Saudi Arabia.
Polymers (Basel). 2022 Sep 16;14(18):3870. doi: 10.3390/polym14183870.
Hydroxamic acids are recognized chelators for various metals; however, using them as functional groups on carbon nanotubes (CNTs) is rare. In this study, novel multi-walled carbon nanotubes (MWCNTs) functionalized with hydroxamic acid derivatives were developed. The MWCNTs were first oxidized, and the resulting product, MWCNT-COOH (A), was treated with oxalyl chloride to yield MWCNT-COCl. The functionalized MWCNTs were susceptible to reacting with the hydroxylamine derivatives of type R-NHOH and produced MWCNTs functionalized with the following hydroxamic acid derivatives (MWCNT-HA): MWCNT-CONOHMe (B), MWCNT-CONOHCOMe(C), and MWCNT-CONOHPh (D). The synthesized derivatives were confirmed by various techniques such as scanning electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. In order to examine their chelation ability, these materials were examined as possible new adsorbents for harmful Pb(II) particles. The adsorption efficiency of the functionalized MWCNT adsorbents toward Pb(II) was investigated. The effects of the adsorbent dose, temperature, pH, and time on adsorption efficiency were considered, and adsorption boundaries that resulted in enhanced effectiveness were obtained. The developed materials were found to have extraordinary coordination sites, such as amine, hydroxyl, and carboxyl groups, which served as excellent chelating specialists for the Pb(II) particles. Thermodynamic and kinetic investigations revealed the unconstrained nature of the adsorption of Pb(II) by the developed MWCNT adsorbents at room temperature. The adsorption was noted to follow the pseudo-second-order and Langmuir isotherm models.
异羟肟酸是公认的各种金属的螯合剂；然而，将它们用作碳纳米管（CNT）上的官能团却很少见。在本研究中，开发了用异羟肟酸衍生物功能化的新型多壁碳纳米管（MWCNT）。首先将MWCNT氧化，所得产物MWCNT-COOH（A）用草酰氯处理，得到MWCNT-COCl。功能化的MWCNT易于与R-NHOH型羟胺衍生物反应，并生成用以下异羟肟酸衍生物功能化的MWCNT（MWCNT-HA）：MWCNT-CONOHMe（B）、MWCNT-CONOHCOMe（C）和MWCNT-CONOHPh（D）。通过扫描电子显微镜、X射线光电子能谱和拉曼光谱等各种技术对合成的衍生物进行了确认。为了检验它们的螯合能力，将这些材料作为有害Pb（II）颗粒的新型吸附剂进行了研究。研究了功能化MWCNT吸附剂对Pb（II）的吸附效率。考虑了吸附剂剂量、温度、pH和时间对吸附效率的影响，并获得了提高有效性的吸附边界。发现所开发的材料具有特殊的配位位点，如胺基、羟基和羧基，这些位点是Pb（II）颗粒的优秀螯合专家。热力学和动力学研究表明，所开发的MWCNT吸附剂在室温下对Pb（II）的吸附具有不受限制的性质。吸附遵循伪二级和朗缪尔等温线模型。
