Selective adsorption of zwitterionic viscose fiber treated with sodium chloroacetate and hyperbranched polyethylenimine
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ORIGINAL RESEARCH
Selective adsorption of zwitterionic viscose fiber treated with sodium chloroacetate and hyperbranched polyethylenimine Chunxiao Zhang1 · Yang Liu1 Received: 17 April 2020 / Accepted: 26 September 2020 © Iran Polymer and Petrochemical Institute 2020
Abstract Anionic modified viscose fiber (AVF) was prepared by using viscose fiber (VF) as raw material, sodium hydroxide as catalyst and sodium chloroacetate as modification reagent. The COOH content of anionic viscose fiber was 109.25 mmol/kg. Anionic viscose fibers were modified with branched polyethylenimine (HPEI) at 140 °C hydrothermal environment using a high-pressure reaction kettle. Zwitterionic viscose fibers (AVF-g-HPEI) with different amino and carboxyl contents could be obtained by changing the ratio of the two modified reagents. Increasing HPEI dosage resulted in amide group content of zwitterionic viscose fibers ranging from 0 to 108.35 mmol/kg. The zwitterionic viscose fibers were characterized by IR, SEM and XPS. IR analysis showed that zwitterionic viscose fiber was successfully prepared. SEM analysis showed that the reaction mainly occurred on the surface of the fiber, and the fiber structure was not changed. XPS analysis demonstrated that with the HPEI dosage increasing nitrogen elements on the surface of zwitterionic viscose fiber increased significantly. Dye adsorption experiments indicated that (1) AVF-g-HPEI could selectively adsorb the anionic dye or the cationic dye (such as methyl orange and methylene blue) from the mixed solution after the pre-treatment with pH 4.5 or pH 10.5 solution, respectively, (2) the dyes adsorbed by zwitterionic viscose fiber could be desorbed in the aqueous solution of pH 4.5 or 10.5, respectively and (3) the desorption ratio of AVF-g-HPEI remained above 0.85 after eight cycles. Keywords Viscose fiber · Zwitterionic · Hyperbranched polyethylenimine · Selective adsorption · Dye
Introduction With the rapid development of world economy, the problem of environmental pollution is becoming more and more serious, especially air pollution and water pollution [1, 2]. Dyes are widely used in textiles, paper, pharmaceuticals and food industries. Their annual output has exceeded 7 × 105 tons and most of them are health and environmental hazards [3]. Therefore, many physico–chemical and biotechnological methods and processes have been used to remove dye residues, heavy metals, and waste gases [4–9]. Among these methods and processes, adsorption is one of the most attractive and promising technologies [10, 11]. Scientists have developed many kinds of adsorbents used in environmental treatments, such as TiO2 immobilized on activated carbon [12, 13], high surface area activated carbons * Chunxiao Zhang [email protected]; [email protected] 1
Shengli College, China University of Petroleum, Dongying 257061, China
[14–16], carbon nanotubes [17], magnetic nanoparticles [18, 19], metal–organic frameworks [20, 21], porous diatomite ceramic filter [22], novel stimuli-responsive hydrogels [23–25], and s
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