Efficient adsorption of 1-alkyl-3-methylimidazolium chloride ionic liquids onto modified cellulose microspheres

• Published in: Carbohydrate polymers 2015-09, Vol.128, p.171-178
• Main Authors: Xu, Min, Ao, Yinyong, Wang, Shuojue, Peng, Jing, Li, Jiuqiang, Zhai, Maolin
• Format: Article
• Language: English
• Subjects: Adsorption; Cellulose - chemistry; Cellulose microsphere; Emulsion grafting; Epoxy Compounds - chemistry; Imidazoles - chemistry; Ionic liquid; Ionic Liquids - chemistry; Methacrylates - chemistry; Microspheres; Pre-irradiation; Waste Disposal, Fluid - methods; Water Pollutants, Chemical - chemistry
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2015.04.018

•Novel cellulose microspheres were prepared by radiation grafting and sulfonation.•The resultant microspheres could remove efficiently trace [CnMIM]Cl from water.•Pseudo-second-order and Langmuir models could fit the adsorption of adsorbents.•The adsorbent could be regenerated for 4 cycles without significant attrition loss. A novel sulfonated cellulose microsphere adsorbent (CGS) was prepared by pre-irradiation induced emulsion grafting of glycidyl methacrylate (GMA) onto the cellulose microsphere, followed by sulfonation. The resulting CGS exhibited superior adsorption ability toward 1-alkyl-3-methylimidazolium chloride ([CnMIM]Cl) ionic liquids (ILs). The adsorption equilibrium could be attained rapidly within 40min for representative 1-butyl-3-methylimidazolium chloride ([C4MIM]Cl) using CGS with different amounts of SO3H group. The adsorption behavior of CGS toward [C4MIM]Cl was well described by the pseudo-second-order model and the Langmuir model. The maximum adsorption capacity toward [C4MIM]Cl was 1.08mmol/g in the wide range of pH (4.8–10.1). In addition, the adsorption capacity of CGS toward [CnMIM]Cl increased with the alkyl length of cations of [CnMIM]Cl due to the hydrophobic interaction and cation exchange adsorption. Spent CGS could be easily regenerated by 0.1mol/L HCl or NaCl. The results indicated that this new adsorbent is useful in removing ILs from wastewater.