| 摘要: |
| 众所周知, 源于羧甲基甲壳素(carboxymethyl chitin, CMC)的吸附材料在重金属离子和染料的去除方面具备诸多优势, 如高效吸附性、选择吸附性、环境友好、制备原料储量丰富等。为有效去除不同水介质(去离子水、模拟废水、自来水和海水)中的六价铬Cr(Ⅵ), 将甲壳质(chitin, CT)羧甲基化获得CMC, 后以聚乙烯亚胺(polyethyleneimine, PEI)为交联剂和功能基团, 采用反相乳化法首次合成了一种新的PEI修饰的CMC复合微球(CMC-PEI), 并对CMC-PEI微球的理化性质、吸附条件及吸附机理进行了研究。结果表明, PEI通过酰胺反应成功接枝到CMC上形成CMC-PEI微球。CMC-PEI微球对Cr(Ⅵ)的吸附行为符合伪二级动力学模型, 说明在吸附Cr(Ⅵ)的过程中, 化学吸附起主导作用。根据Liu模型计算得知, CMC-PEI微球对Cr(Ⅵ)的最大理论吸附量为244.01 mg/g。吸附-解吸附实验发现, NaOH能有效地从微球表面解吸Cr(Ⅵ), 表明吸附后的微球具有良好的循环再生性能。光谱学分析结果表明, CMC-PEI微球对Cr(Ⅵ)的去除主要包括静电相互作用、还原反应和配位作用。另外, 不同水介质实验结果表明, CMC-PEI微球对去离子水、模拟废水、自来水和海水中的Cr(Ⅵ)有良好的去除效果。总之, 该微球制备工艺简单、成本低、节约资源和易推广, 可以为净化受铬污染的不同水体提供重要参考。 |
| 关键词: 羧甲基甲壳质微球 聚乙烯亚胺 六价铬Cr(Ⅵ) 吸附 吸附机理 |
| DOI：10.11693/hyhz20230400091 |
| 分类号:X703 |
| 基金项目:国家自然科学基金项目,31400812号 |
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| POLYETHYLENEIMINE-MODIFIED CARBOXYMETHYL CHITIN MICROSPHERES FOR ADSORPTION TOWARD CR(Ⅵ) IN DIFFERENT AQUEOUS MEDIA |
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LIU Hao1, LIU Xiao-Kun2, DANG Qi-Feng1, LIU Cheng-Sheng1
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1.College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China;2.Marine Biomedical Research Institute of Qingdao, Qingdao 266075, China
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| Abstract: |
| The adsorption materials based on carboxymethyl chitin (CMC) have many advantages in the adsorption to heavy metal ions and dyes, such as high efficiency, selective adsorption, environmental friendliness, and abundant raw materials. For the removal of Cr(Ⅵ) in different aqueous media (deionized water, simulated wastewater, tap water, and seawater), CMC was firstly prepared through the methylation of chitin (CT), and then novel CMC-PEI microspheres were fabricated for the first time via grafting polyethyleneimine (PEI) onto CMC by the reverse-phase emulsification method, in which PEI was used as a cross-linker and also endowed CMC with good adsorption capability. The physicochemical properties of CMC-PEI microspheres were characterized by a series of techniques, such as FTIR, XRD, thermogravimetric (TG) analysis, differential thermogravimetric (DTG) analysis, elemental analysis (EA), and light microscopy; and results indicate that PEI was successfully grafted onto CMC by the amide reaction. The adsorption experiments showed that the adsorption behavior of CMC-PEI microspheres to Cr(Ⅵ) was in concordance with the pseudo-second-order kinetic model, indicating that chemisorption was dominant in the adsorption process. According to the calculated results based on the Liu model, the maximum theoretical adsorption capacity for Cr(Ⅵ) was 244.01 mg/g. The adsorption-desorption experimental results show that NaOH could effectively desorb Cr(Ⅵ) from microspheres' surfaces, implying that CMC-PEI microspheres had good regeneration performance. X-ray photoelectron spectroscopy (XPS) results confirm preliminarily that the adsorption mechanisms of CMC-PEI microspheres to Cr(Ⅵ) might include electrostatic interaction, reduction reaction, and coordination. In addition, the results of adsorption experiments in different aqueous media show that CMC-PEI microspheres had good removal capabilities to Cr(Ⅵ). Overall, novel CMC-PEI microspheres with good reusability and high adsorption capacity for Cr(Ⅵ) should serve as a promising adsorbent for different Cr(Ⅵ)-polluted water bodies' scavenging. |
| Key words: carboxymethyl chitin microsphere polyethyleneimine Cr(Ⅵ) adsorption adsorption mechanism |
