Alkali recovery using PVA/SiO2 cation exchange membranes with different –COOH contents

Hao, Jianwen; Gong, Mali; Wu, Yonghui; Wu, Cuiming; Luo, Jingyi; Xu, Tongwen

doi:10.1016/j.jhazmat.2012.11.056

Cited by 41 publications

(32 citation statements)

References 32 publications

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“…In the previous researches [5,8,11,12,13], PVA-based composite membranes were usually treated at a high temperature to promote the sol-gel process as well as the condensation between –OH groups. Therefore in this work, composite membranes were heated at 100 °C and 120 °C to detect the effects of thermal treatment conditions on the separation performance of the composite membranes.…”

Section: Resultsmentioning

confidence: 99%

“…However, in addition, it is necessary for PVA-based membranes to incorporate functional groups (such as –COO − or –SO 3 − ) and crosslink linear PVA chains to enhance sustainability during the running process. For instance, Yonghui Wu et al [11,12,13] prepared a series of PVA-based organic–inorganic hybrid membranes from a PVA solution and a multi-silicon crosslinking agent via the sol-gel process. The as-prepared hybrid membranes possessed enhanced ion flux as well as OH − ion selectivity compared with the commercial ones.…”

Section: Introductionmentioning

confidence: 99%

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Composite Cationic Exchange Membranes Prepared from Polyvinyl Alcohol (PVA) and Boronic Acid Copolymers for Alkaline Diffusion Dialysis

et al. 2018

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Boronic acid copolymers with a large number of functional groups were obtained via a free radical polymerization method. The corresponding composite membranes for alkaline diffusion dialysis (DD) were prepared by a crosslinking reaction between polyvinyl alcohol (PVA) and the as-obtained boronic acid copolymers. The composite membranes possessed water uptake (WR) of 122.1–194.4%, ion exchange capacities (IECs) of 0.79–1.17 mmol/g, as well as both good mechanical stability (tensile strength of 40.7–49.9 MPa and elongation at break of 52.1–121.1%) and thermal stability. The as-prepared membranes were stable in 2 M NaOH solution at 65 °C with a swelling degree and mass loss of as-prepared membranes in the range of 305–368% and 9.2–22%, respectively. A NaOH/Na2WO4 mixture was used to investigate the separation properties of as-prepared membranes via the DD process. Results indicated that the dialysis coefficients of OH− (UOH) were in the range of 0.0079–0.0150 m/h, while the separation factors (S) were in the range of 26.6–53.2. The functional groups from boronic acid copolymer and –OH from PVA were demonstrated to promote the ion transport synergistically.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Composite Cationic Exchange Membranes Prepared from Polyvinyl Alcohol (PVA) and Boronic Acid Copolymers for Alkaline Diffusion Dialysis

et al. 2018

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“…[19][20][21][22][23][24] Because of its superior hydrophilicity, citric acid (CA) cross-linked PVA membrane has been used as a pervaporation membrane to separate water during esterification but not as a catalyst support. 22 In addition, PVA was used as a main membrane matrix to prepare poly (styrene sulfonic acid) (PSSA)/PVA membrane for catalyzing esterification although its role as a water absorber was not recognized.…”

Section: Introductionmentioning

confidence: 99%

Esterification of fatty acids from waste cooking oil to biodiesel over a sulfonated resin/PVA composite

Zhang

Gao

Zhao

et al. 2016

Catal. Sci. Technol.

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(2016) Esterification of fatty acids from waste cooking oil to biodiesel over a sulfonated resin/PVA composite. Catalysis Science and Technology, 2016 (6). pp. 5590-5598. ISSN 2044-4761 Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/33644/1/ZhangHL%20Catalysis%20Science %20%26%20Technology%202016%20online.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the University of Nottingham End User licence and may be reused according to the conditions of the licence. For more details see: http://eprints.nottingham.ac.uk/end_user_agreement.pdf A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. Sulfonated cation exchange resins (s-CER) have been widely studied as a replacement of liquid acids for the catalysis of esterification of free fatty acids (FFAs) to produce biodiesel with water as the only by-product. However, the water produced has strong affinity to sulfonate groups in s-CER, which blocks the reactive sites for esterification and thus reduces the activity of the catalyst. To overcome this technical barrier, we have designed an s-CER/PVA composite by incorporating s-CER fines within a poly (vinyl alcohol) (PVA) matrix. PVA has much stronger absorption preference of water than s-CER and has very low selectivity for the reactants (FFAs and methanol), which enables the continuous removal of the produced water and liberation of reactive sulfonate sites in s-CER for catalysis. With s-CER/PVA, the FFAs conversion was increased from 80.1 % to 97.5 % after 8-hour reaction and the turnover frequency (TOF) was increased more than 3.3 times. The TOF of s-CER/PVA was also 2.6 times of that of sulfuric acid, suggesting that the water less, heterogeneous sulfonate sites are more reactive than water-blocked homogeneous ones. The reusability of the s-CER/PVA was also enhanced due to that the produced water that could cause deactivation of the s-CER was largely removed by PVA.

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“…Next, the mixture and the diffusate were removed from both sides. The concentration of OH − was determined by the HCl titration method, while the concentration of WO 4 2− was measured by thiocyanate spectrophotometry [ 30 ]. The separation factor (S) was the ratio of the dialysis coefficient ( U ) of OH − and WO 4 2− .…”

Section: Methodsmentioning

confidence: 99%

Preparation of Polyvinyl Alcohol (PVA)-Based Composite Membranes Using Carboxyl-Type Boronic Acid Copolymers for Alkaline Diffusion Dialysis

et al. 2020

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Carboxyl-type boronic acid copolymers (CBACs) were synthesized by a radical polymerization method and used for the preparation of polyvinyl alcohol (PVA)-based composite membranes via a solution mixture method. The as-prepared composite membranes exhibited a water uptake (WR) of 122.6–150.0%, an ion exchange capacity (IEC) of 0.0147–0.0518 mmol g−1, and excellent mechanical (elongation at break (Eb) of 103.8–148.4%, tensile strength (TS) of 38.7–58.6 MPa) and thermal stability. The alkali resistances of the as-prepared membranes were tested by immersing the samples into 2 mol L−1 NaOH solutions at 25 °C for 60 h, and the results were encouraging: the mass loss and swelling degree of the as-prepared membranes were in the ranges of 1.9–5.9% and 222.6–241.9%, respectively. The separation performances of the as-prepared membranes were evaluated by the diffusion dialysis (DD) process with an NaOH/Na2WO4 mixture at room temperature. The results demonstrated that the dialysis coefficients of hydroxide (UOH) were in the range of 0.0147–0.0347 m h−1, and the separation factors (S) were in the range of 29.5–62.6. The introduced carboxyl groups from CBACs and the –OH groups from PVA were both deemed to play significant roles in the promotion of ion transport: the –COO− groups formed negatively charged transport channels for Na+ by electrostatic attraction, and the –OH groups promoted the transport of OH− via hydrogen bonding.

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Alkali recovery using PVA/SiO2 cation exchange membranes with different –COOH contents

Cited by 41 publications

References 32 publications

Composite Cationic Exchange Membranes Prepared from Polyvinyl Alcohol (PVA) and Boronic Acid Copolymers for Alkaline Diffusion Dialysis

Composite Cationic Exchange Membranes Prepared from Polyvinyl Alcohol (PVA) and Boronic Acid Copolymers for Alkaline Diffusion Dialysis

Esterification of fatty acids from waste cooking oil to biodiesel over a sulfonated resin/PVA composite

Preparation of Polyvinyl Alcohol (PVA)-Based Composite Membranes Using Carboxyl-Type Boronic Acid Copolymers for Alkaline Diffusion Dialysis

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