• 关键词：过氧化氢  纤维素  聚乙烯亚胺  Cr(Ⅵ)  吸附

• 基金项目：四川省科技支撑项目（No.2016GZ0222）

• 陈豪宇
• 西南交通大学地球科学与环境工程学院, 成都 611756

• 张胜利
• 西南交通大学地球科学与环境工程学院, 成都 611756

• 凯橙橙
• 西南交通大学地球科学与环境工程学院, 成都 611756

• 张思略
• 西南交通大学地球科学与环境工程学院, 成都 611756

• 姜曼
• 西南交通大学材料科学与工程学院, 成都 610031

• 周祚万
• 西南交通大学材料科学与工程学院, 成都 610031

• 付金丽
• 成都丽雅纤维股份有限公司, 成都 610300

• 摘要：采用低浓度H₂O₂氧化纤维素水凝胶纤维，再接枝聚乙烯亚胺（PEI），成功制得PEI改性纤维素纤维（PEI-OCF）吸附剂，并将其用于溶液中Cr（Ⅵ）的去除.同时，利用傅里叶变换衰减全反射红外光谱（ATR-FTIR）和X射线能谱（EDX）分析，确证纤维素上的羟基被H₂O₂氧化成醛基，PEI通过席夫碱反应被接枝到氧化纤维素上.制备优化结果表明，H₂O₂氧化阶段的最佳条件为pH=4.0，H₂O₂质量分数0.2%，氧化时间3.0 h，氧化温度85℃；PEI接枝阶段的最佳条件为pH=11.0，PEI质量分数3.0%，接枝时间0.5 h.吸附研究结果显示，Cr（VI）在PEI-OCF上的吸附具有强烈的pH依赖性，最佳pH值为2.0.在180 min时吸附达到平衡；吸附过程符合准二级动力学模型，且主要由化学吸附控制.与Freundlich模型相比，Langmuir模型能更好地描述吸附过程；当温度为15和25℃时，最大吸附量分别为110.61和119.04 mg·g^-1.浓度为300和600 mg·L^-1的共存离子Ca²⁺、Mg²⁺和Na⁺对PEI-OCF吸附Cr（VI）的影响较小.上述结果表明，PEI-OCF对Cr（Ⅵ）吸附性能良好，使用中易于分离；且制备过程无需交联剂，使用可降解材料，绿色环保.

• Abstract：Polyethyleneimine modified cellulose fiber (PEI-OCF) was successfully prepared by grafting polyethylenimine (PEI) onto oxidized cellulose fiber, which was obtained via hydrogen peroxide (H₂O₂) oxidizing cellulose gel. Meanwhile, the removal of Cr(VI) from aqueous solution by PEI-OCF was carried out. It was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATRFT-IR) and energy dispersive X-ray spectroscopy (EDX) that the hydroxyl groups of cellulose were oxidized to aldehyde groups by H₂O₂, and PEI was introduced onto the oxidized cellulose via Schiff-base reaction. The optimal preparation conditions were investigated in batch mode. Results show that the optimum oxidation conditions were pH of 4.0, 0.2% of H₂O₂ concentration, 3.0 h of oxidation time and 85℃ of oxidation temperature. At PEI-grafting stage, the optimum conditions were pH 11.0, 3.0% of PEI concentration, and 0.5 h of oxidation time at room temperature. Adsorption results show that Cr(VI) adsorption on PEI-OCF was highly pH-dependent, and the optimum pH was 2.0. The adsorption equilibrium reached at about 180 min. The adsorption system followed pseudo-second-order kinetic model, and chemisorption was the rate-limiting step. The Langmuir isotherm model gave a better fitting to the equilibrium data than the Freundlich isotherm model. The maximum adsorption capacity was 110.61 and 119.04 mg·g^-1 at 15 and 30℃, respectively. Coexisting ions under 300 and 600 mg·L^-1 of (Ca²⁺, Mg²⁺ and Na⁺) had no significant effect on the adsorption capacity of Cr(VI). In conclusion, the prepared PEI-OCF has a good adsorption capacity for Cr(VI) pollutant and is easily separated from the aqueous solution. Furthermore, the preparation of PEI-OCF is an environmentally friendly process with biodegradable cellulose as raw material and without using any crosslink agents.

• Key words：H₂O₂  cellulose  polyethylenimine (PEI)  Cr(VI)  adsorption

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