Modified polystyrene anion exchange resins with long chain alkyl groups to enhance the aldolization reaction selectivity

Wang, Jiexiang; Wang, Qiang; Li, Yunhua; Chen, Binghong; Zhang, Ruyun

doi:10.1016/j.apcata.2012.11.028

Cited by 8 publications

(4 citation statements)

References 38 publications

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“…It was very interesting that the grafting density varied from 14.47 to 35.34% with the length of alkylamine, while a higher grafting percentage was obtained with longer alkyl groups. 49 Especially, the grafting density of DANC-Ste was as high as 30.83%, which corresponded to 1.17 mmol/g octadecyl groups. The original content of aldehyde groups in DANC was 2.20 mmol/g based on the titration experiment, where 53.18% was converted and covalently linked with octadecyl groups, which offered extensively hydrophobic properties to the nanocellulose.…”

Section: Resultsmentioning

confidence: 95%

“…The percentage of carbon, hydrogen, and nitrogen in grafting products all increased compared with that of NC and DANC, indicating that the surface grafting was carried out successfully. It was very interesting that the grafting density varied from 14.47 to 35.34% with the length of alkylamine, while a higher grafting percentage was obtained with longer alkyl groups . Especially, the grafting density of DANC-Ste was as high as 30.83%, which corresponded to 1.17 mmol/g octadecyl groups.…”

Section: Resultsmentioning

confidence: 97%

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High-Flux Nanofibrous Composite Reverse Osmosis Membrane Containing Interfacial Water Channels for Desalination

Wang

et al. 2023

ACS Appl. Mater. Interfaces

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A nanofibrous composite reverse osmosis (RO) membrane with a polyamide barrier layer containing interfacial water channels was fabricated on an electrospun nanofibrous substrate via an interfacial polymerization process. The RO membrane was employed for desalination of brackish water and exhibited enhanced permeation flux as well as rejection ratio. Nanocellulose was prepared by sequential oxidations of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and sodium periodate systems and surface grafting with different alkyl groups including octyl, decanyl, dodecanyl, tetradecanyl, cetyl, and octadecanyl groups. The chemical structure of the modified nanocellulose was verified subsequently by Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), and solid NMR measurements. Two monomers, trimesoyl chloride (TMC) and m-phenylenediamine (MPD), were employed to prepare a cross-linked polyamide matrix, i.e., the barrier layer of the RO membrane, which integrated with the alkyl groups-grafted nanocellulose to build up interfacial water channels via interfacial polymerization. The top and cross-sectional morphologies of the composite barrier layer were observed by means of scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM) to verify the integration structure of the nanofibrous composite containing water channels. The aggregation and distribution of water molecules in the nanofibrous composite RO membrane verified the existence of water channels, demonstrated by molecular dynamics (MD) simulations. The desalination performance of the nanofibrous composite RO membrane was conducted and compared with that of commercially available RO membranes in the processing of brackish water, where 3 times higher permeation flux and 99.1% rejection ratio against NaCl were accomplished. This indicated that the engineering of interfacial water channels in the barrier layer could substantially increase the permeation flux of the nanofibrous composite membrane while retaining the high rejection ratio as well, i.e., to break through the trade-off between permeation flux and rejection ratio. Antifouling properties, chlorine resistance, and long-term desalination performance were also demonstrated to evaluate the potential applications of the nanofibrous composite RO membrane; remarkable durability and robustness were achieved in addition to 3 times higher permeation flux and a higher rejection ratio against commercial RO membranes in brackish water desalination.

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 97%

High-Flux Nanofibrous Composite Reverse Osmosis Membrane Containing Interfacial Water Channels for Desalination

Wang

et al. 2023

ACS Appl. Mater. Interfaces

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“…29 That is to say different kinds of acids play different roles during the breakage process of MCC. Meanwhile, the larger BET surface areas in the Fe-resin, which can be attributed to the suitable compromise of FeCl 3 between solubility and molecular size 30 for the ion-exchange, the larger radius of tervalence iron and the emergence of the steric hindrance 31 after the replacement of H ions by Fe ions on −SO 3 , also have positive effects on the contact of cellulose and surface acid sites on Fe-resin. The above analysis suggested that the yield of WSSs was higher than that in the hydrolysate of MCC catalyzed by H-resin, as well as the selectivity of glucose, LA, and WSSs.…”

Section: Conversion Of Amorphousmentioning

confidence: 99%

Selective Decomposition of Cellulose into Glucose and Levulinic Acid over Fe-Resin Catalyst in NaCl Solution under Hydrothermal Conditions

Yang

Wang

Jia

et al. 2014

Ind. Eng. Chem. Res.

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The selective decomposition of microcrystalline cellulose (MCC) by Fe-resin (a modified Dowex 50 by cationexchange) solid catalyst in 5 wt % NaCl solution under hydrothermal conditions has been investigated. The conversion of MCC increases from 24.4% (without catalyst) to 90.9%, and the yield of glucose and levulinic acid (LA) increases from 0.6% and 1.1% (without catalyst) to 38.7% and 33.3%, respectively, under 200 °C for 5 h. The role that Fe-resin/NaCl played in the system is discussed in detail: NaCl could disrupt the hydrogen-bond matrix among cellulose fibers to change highly crystalline cellulose into an amorphous form; Lewis acids on the Fe-resin further boost the depolymerization of amorphous cellulose into watersoluble sugars (WSSs); Fe ions on Fe-resin progressively released into NaCl solution are beneficial to the conversion of WSSs to glucose and LA. A three-step degradation scheme reflecting the main pathways of MCC degradation in the reaction is proposed.

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“…The long alkyl chain addition at the exchange sites of resins could be of great benefit for the preferable selectivity toward monovalent anions because of its steric hindrance and hydrophobic effect [19,20]. Hence, it is intriguing for us to modify the weakly basic resin by introducing long alkyl groups around the active amine groups, which can easily form strongly basic functional groups (quaternary ammonium) which interact with NO 3 − -N through strong electrostatic attraction.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Nitrate by a Novel Polyacrylic Anion Exchange Resin from Water with Dissolved Organic Matters: Batch and Column Study

et al. 2019

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A novel anion exchange resin AEE-3 was synthesized by N-alkylation of a weakly basic polyacrylic anion exchanger D311 with 1-bromopropane to effectively remove nitrate (NO3−-N) from aqueous solution. The related finding revealed that its adsorption isotherm obeyed the Langmuir model well, and the second-order model was more validated for the NO3−-N adsorption kinetics study. Compared to commercially-available polystyrene-based nitrate specialty resin Purolite A 520E (A520E), AEE-3 resin has a higher adsorbed amount and better regeneration performance toward NO3−-N in the existence of dissolved organic matter (DOM) using static and dynamic methods. Notably, a real secondary treated wastewater (STWW) obtained from a local municipal wastewater treatment plant was also assessed for NO3−-N removal in fixed-bed columns. Observations from this study indicated that AEE-3 could effectively remove NO3−-N from contaminated surface water.

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Modified polystyrene anion exchange resins with long chain alkyl groups to enhance the aldolization reaction selectivity

Cited by 8 publications

References 38 publications

High-Flux Nanofibrous Composite Reverse Osmosis Membrane Containing Interfacial Water Channels for Desalination

High-Flux Nanofibrous Composite Reverse Osmosis Membrane Containing Interfacial Water Channels for Desalination

Selective Decomposition of Cellulose into Glucose and Levulinic Acid over Fe-Resin Catalyst in NaCl Solution under Hydrothermal Conditions

Adsorption of Nitrate by a Novel Polyacrylic Anion Exchange Resin from Water with Dissolved Organic Matters: Batch and Column Study

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