Calcium Alginate Production through Forward Osmosis with Reverse Solute Diffusion and Mechanism Analysis
Calcium alginate (Ca-Alg) is a novel target product for recovering alginate from aerobic granular sludge. A novel Ca-Alg production method was proposed herein where Ca-Alg was formed in a sodium alginate (SA) feed solution (FS) and concentrated via forward osmosis (FO) with Ca<sup>2+</sup&g...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-02-01
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| Series: | Membranes |
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| Online Access: | https://www.mdpi.com/2077-0375/13/2/207 |
| _version_ | 1797619352688656384 |
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| author | Da-Qi Cao Kai Tang Wen-Yu Zhang Cheng Chang Jia-Lin Han Feng Tian Xiao-Di Hao |
| author_facet | Da-Qi Cao Kai Tang Wen-Yu Zhang Cheng Chang Jia-Lin Han Feng Tian Xiao-Di Hao |
| author_sort | Da-Qi Cao |
| collection | DOAJ |
| description | Calcium alginate (Ca-Alg) is a novel target product for recovering alginate from aerobic granular sludge. A novel Ca-Alg production method was proposed herein where Ca-Alg was formed in a sodium alginate (SA) feed solution (FS) and concentrated via forward osmosis (FO) with Ca<sup>2+</sup> reverse osmosis using a draw solution of CaCl<sub>2</sub>. An abnormal reverse solute diffusion was observed, with the average reverse solute flux (RSF) decreasing with increasing CaCl<sub>2</sub> concentrations, while the average RSF increased with increasing alginate concentrations. The RSF of Ca<sup>2+</sup> in FS decreased continuously as the FO progressed, using 1.0 g/L SA as the FS, while it increased initially and later decreased using 2.0 and 3.0 g/L SA as the FS. These results were attributed to the Ca-Alg recovery production (CARP) formed on the FO membrane surface on the feed side, and the percentage of Ca<sup>2+</sup> in CARP to total Ca<sup>2+</sup> reverse osmosis reached 36.28%. Scanning electron microscopy and energy dispersive spectroscopy also verified CARP existence and its Ca<sup>2+</sup> content. The thin film composite FO membrane with a supporting polysulfone electrospinning nanofiber membrane layer showed high water flux and RSF of Ca<sup>2+</sup>, which was proposed as a novel FO membrane for Ca-Alg production via the FO process with Ca<sup>2+</sup> reverse diffusion. Four mechanisms including molecular sieve role, electrification of colloids, osmotic pressure of ions in CARP, and FO membrane structure were proposed to control the Ca-Alg production. Thus, the results provide further insights into Ca-Alg production via FO along with Ca<sup>2+</sup> reverse osmosis. |
| first_indexed | 2024-03-11T08:25:54Z |
| format | Article |
| id | doaj.art-121127f4216e46b7a57ef40bd5bf8d84 |
| institution | Directory Open Access Journal |
| issn | 2077-0375 |
| language | English |
| last_indexed | 2024-03-11T08:25:54Z |
| publishDate | 2023-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Membranes |
| spelling | doaj.art-121127f4216e46b7a57ef40bd5bf8d842023-11-16T22:02:48ZengMDPI AGMembranes2077-03752023-02-0113220710.3390/membranes13020207Calcium Alginate Production through Forward Osmosis with Reverse Solute Diffusion and Mechanism AnalysisDa-Qi Cao0Kai Tang1Wen-Yu Zhang2Cheng Chang3Jia-Lin Han4Feng Tian5Xiao-Di Hao6Sino-Dutch R&D Centre for Future Wastewater Treatment Technologies/Key Laboratory of Urban Stormwater System and Water Environment, Beijing University of Civil Engineering and Architecture, Beijing 100044, ChinaSino-Dutch R&D Centre for Future Wastewater Treatment Technologies/Key Laboratory of Urban Stormwater System and Water Environment, Beijing University of Civil Engineering and Architecture, Beijing 100044, ChinaInstitute of Soil Environment and Pollution Remediation, Beijing Municipal Research Institute of Environmental Protection, Beijing 100037, ChinaInstitute of Chemical Engineering, Chemical and Process Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UKSino-Dutch R&D Centre for Future Wastewater Treatment Technologies/Key Laboratory of Urban Stormwater System and Water Environment, Beijing University of Civil Engineering and Architecture, Beijing 100044, ChinaSino-Dutch R&D Centre for Future Wastewater Treatment Technologies/Key Laboratory of Urban Stormwater System and Water Environment, Beijing University of Civil Engineering and Architecture, Beijing 100044, ChinaSino-Dutch R&D Centre for Future Wastewater Treatment Technologies/Key Laboratory of Urban Stormwater System and Water Environment, Beijing University of Civil Engineering and Architecture, Beijing 100044, ChinaCalcium alginate (Ca-Alg) is a novel target product for recovering alginate from aerobic granular sludge. A novel Ca-Alg production method was proposed herein where Ca-Alg was formed in a sodium alginate (SA) feed solution (FS) and concentrated via forward osmosis (FO) with Ca<sup>2+</sup> reverse osmosis using a draw solution of CaCl<sub>2</sub>. An abnormal reverse solute diffusion was observed, with the average reverse solute flux (RSF) decreasing with increasing CaCl<sub>2</sub> concentrations, while the average RSF increased with increasing alginate concentrations. The RSF of Ca<sup>2+</sup> in FS decreased continuously as the FO progressed, using 1.0 g/L SA as the FS, while it increased initially and later decreased using 2.0 and 3.0 g/L SA as the FS. These results were attributed to the Ca-Alg recovery production (CARP) formed on the FO membrane surface on the feed side, and the percentage of Ca<sup>2+</sup> in CARP to total Ca<sup>2+</sup> reverse osmosis reached 36.28%. Scanning electron microscopy and energy dispersive spectroscopy also verified CARP existence and its Ca<sup>2+</sup> content. The thin film composite FO membrane with a supporting polysulfone electrospinning nanofiber membrane layer showed high water flux and RSF of Ca<sup>2+</sup>, which was proposed as a novel FO membrane for Ca-Alg production via the FO process with Ca<sup>2+</sup> reverse diffusion. Four mechanisms including molecular sieve role, electrification of colloids, osmotic pressure of ions in CARP, and FO membrane structure were proposed to control the Ca-Alg production. Thus, the results provide further insights into Ca-Alg production via FO along with Ca<sup>2+</sup> reverse osmosis.https://www.mdpi.com/2077-0375/13/2/207forward osmosiscalcium alginaterecoveryreverse solute diffusionthin film composite forward osmosis membraneelectrospinning nanofiber membrane |
| spellingShingle | Da-Qi Cao Kai Tang Wen-Yu Zhang Cheng Chang Jia-Lin Han Feng Tian Xiao-Di Hao Calcium Alginate Production through Forward Osmosis with Reverse Solute Diffusion and Mechanism Analysis Membranes forward osmosis calcium alginate recovery reverse solute diffusion thin film composite forward osmosis membrane electrospinning nanofiber membrane |
| title | Calcium Alginate Production through Forward Osmosis with Reverse Solute Diffusion and Mechanism Analysis |
| title_full | Calcium Alginate Production through Forward Osmosis with Reverse Solute Diffusion and Mechanism Analysis |
| title_fullStr | Calcium Alginate Production through Forward Osmosis with Reverse Solute Diffusion and Mechanism Analysis |
| title_full_unstemmed | Calcium Alginate Production through Forward Osmosis with Reverse Solute Diffusion and Mechanism Analysis |
| title_short | Calcium Alginate Production through Forward Osmosis with Reverse Solute Diffusion and Mechanism Analysis |
| title_sort | calcium alginate production through forward osmosis with reverse solute diffusion and mechanism analysis |
| topic | forward osmosis calcium alginate recovery reverse solute diffusion thin film composite forward osmosis membrane electrospinning nanofiber membrane |
| url | https://www.mdpi.com/2077-0375/13/2/207 |
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