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Sanchez-Salvador JL, Balea A, Negro C, Monte MC, Blanco A. Gel Point as Measurement of Dispersion Degree of Nano-Cellulose Suspensions and Its Application in Papermaking. NANOMATERIALS 2022; 12:nano12050790. [PMID: 35269278 PMCID: PMC8912044 DOI: 10.3390/nano12050790] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/07/2022] [Accepted: 02/22/2022] [Indexed: 12/27/2022]
Abstract
The dispersion degree of cellulose micro and nanofibrils (CMFs/CNFs) in water suspensions is key to understand and optimize their effectiveness in several applications. In this study, we proposed a method, based on gel point (Øg), to calculate both aspect ratio and dispersion degree. This methodology was validated through the morphological characterization of CMFs/CNFs by Transmission Electronic Microscopy. The influence of dispersion degree on the reinforcement of recycled cardboard has also been evaluated by stirring CMF/CNF suspensions at different speeds. Results show that as stirring speed increases, Øg decreased to a minimum value, in which the aspect ratio is maximum. Then, Øg increased again. Suspensions with lower Øg, in the intermediate region of agitation present very good dispersion behavior with an open and spongy network structure, in which nanofibril clusters are totally dispersed. Higher stirring speeds shorten the nanofibrils and the networks collapse. Results show that the dispersion of the nanocellulose at the minimum Øg before their addition to the pulp, produces higher mechanical properties, even higher than when CNFs and pulp are agitated together. This method allows for the determination of the CMF/CNF dispersion, to maximize their behavior as strength agents. This knowledge would be crucial to understand why some industrial trials did not give satisfactory results.
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On the Network Strength of Meta-Aramid Fiber Suspension and Its Relationship to Formation. ADVANCES IN POLYMER TECHNOLOGY 2022. [DOI: 10.1155/2022/3837232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Because of poor surface hydrophilicity, meta-aramid fibers readily form flocs by intertwining or interlacing, and this severely affects the uniformity of meta-aramid paper. To investigate the flocculation mechanism of meta-aramid fiber suspensions, the critical flocculant concentration, shear, and compressive network strength of meta-aramid fiber suspensions were examined. A hand sheet former was used to study the influence of the yielding properties of suspensions on the uniformity of meta-aramid paper, and the relationship between the formation index and rheological properties was determined. The results showed that the critical gel concentration ranged from 0.37 to 0.68 g/L, which was much lower than that of plant fiber suspensions. In addition, the compressive yield stress (
) and shear yield stress (
) of the meta-aramid fiber suspensions were found to increase linearly and exponentially, respectively, with an increasing concentration, and the uniformity index of the paper sheets was found to depend on a power of
. This provides an effective method for predicting paper sheet uniformity.
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3
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Membrane fouling by nanofibres and organic contaminants – Mechanisms and mitigation via periodic cleaning strategies. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.119592] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Tian D, Zhong N, Leung J, Shen F, Hu J, Saddler JN. Potential of Xylanases to Reduce the Viscosity of Micro/Nanofibrillated Bleached Kraft Pulp. ACS APPLIED BIO MATERIALS 2020; 3:2201-2208. [PMID: 35025272 DOI: 10.1021/acsabm.0c00041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The generally high viscosity of micro/nanofibrillated cellulose limits its applications in cream and fluid products. A bleached softwood Kraft (BSK) pulp was refined with increasing energy (500-2500 kWh t-1) to produce micro/nanofibrillated cellulose (MNBSK). Subsequent xylanase treatment was shown to influence the viscosity, gel point, aspect ratio, and fiber surface morphology of the MNBSK. It was apparent that the accessibility to xylanases was increased even at low refining energies (500 kWh t-1). Depending on the initial degree of cellulose fibrillation, xylanase treatment decreased the viscosity of the MNBSK from 4190-2030 to 681-243 Pa·s at a shear rate of 0.01 s-1, corresponding to the reduction in the aspect ratio from 183-296 to 163-194. It was likely that the xylanases were predominantly acting on the xylan present on the fiber surfaces, reducing the cross-linking points on the cellulose fibers and consequently resulting in the reduction in MNBSK viscosity.
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Affiliation(s)
- Dong Tian
- Institute of Ecological and Environmental Sciences, Sichuan Agricultural University, Chengdu, Sichuan 611130, P. R. China.,Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada.,State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065, P. R. China
| | - Na Zhong
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Jerry Leung
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Fei Shen
- Institute of Ecological and Environmental Sciences, Sichuan Agricultural University, Chengdu, Sichuan 611130, P. R. China
| | - Jinguang Hu
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary T2N 1N4, Canada
| | - Jack N Saddler
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
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Balea A, Fuente E, Monte MC, Merayo N, Campano C, Negro C, Blanco A. Industrial Application of Nanocelluloses in Papermaking: A Review of Challenges, Technical Solutions, and Market Perspectives. Molecules 2020; 25:molecules25030526. [PMID: 31991802 PMCID: PMC7037648 DOI: 10.3390/molecules25030526] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/21/2020] [Accepted: 01/23/2020] [Indexed: 01/09/2023] Open
Abstract
Nanocelluloses (NC) increase mechanical and barrier paper properties allowing the use of paper in applications actually covered by other materials. Despite the exponential increase of information, NC have not been fully implemented in papermaking yet, due to the challenges of using NC. This paper provides a review of the main new findings and emerging possibilities in this field by focusing mainly on: (i) Decoupling the effects of NC on wet-end and paper properties by using synergies with retention aids, chemical modification, or filler preflocculation; (ii) challenges and solutions related to the incorporation of NC in the pulp suspension and its effects on barrier properties; and (iii) characterization needs of NC at an industrial scale. The paper also includes the market perspectives. It is concluded that to solve these challenges specific solutions are required for each paper product and process, being the wet-end optimization the key to decouple NC effects on drainage and paper properties. Furthermore, the effect of NC on recyclability must also be taken into account to reach a compromise solution. This review helps readers find upscale options for using NC in papermaking and identify further research needs within this field.
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Affiliation(s)
- Ana Balea
- Department of Chemical Engineering and Materials, Universidad Complutense de Madrid (UCM), Av. Complutense s/n, 28040 Madrid, Spain; (A.B.); (E.F.); (M.C.M.); (N.M.); (C.C.); (C.N.)
| | - Elena Fuente
- Department of Chemical Engineering and Materials, Universidad Complutense de Madrid (UCM), Av. Complutense s/n, 28040 Madrid, Spain; (A.B.); (E.F.); (M.C.M.); (N.M.); (C.C.); (C.N.)
| | - M. Concepcion Monte
- Department of Chemical Engineering and Materials, Universidad Complutense de Madrid (UCM), Av. Complutense s/n, 28040 Madrid, Spain; (A.B.); (E.F.); (M.C.M.); (N.M.); (C.C.); (C.N.)
| | - Noemi Merayo
- Department of Chemical Engineering and Materials, Universidad Complutense de Madrid (UCM), Av. Complutense s/n, 28040 Madrid, Spain; (A.B.); (E.F.); (M.C.M.); (N.M.); (C.C.); (C.N.)
- Department of Mechanical, Chemical and Industrial Design Engineering, ETSIDI, Universidad Politécnica de Madrid (UPM), Ronda de Valencia 3, 28012 Madrid, Spain
| | - Cristina Campano
- Department of Chemical Engineering and Materials, Universidad Complutense de Madrid (UCM), Av. Complutense s/n, 28040 Madrid, Spain; (A.B.); (E.F.); (M.C.M.); (N.M.); (C.C.); (C.N.)
| | - Carlos Negro
- Department of Chemical Engineering and Materials, Universidad Complutense de Madrid (UCM), Av. Complutense s/n, 28040 Madrid, Spain; (A.B.); (E.F.); (M.C.M.); (N.M.); (C.C.); (C.N.)
| | - Angeles Blanco
- Department of Chemical Engineering and Materials, Universidad Complutense de Madrid (UCM), Av. Complutense s/n, 28040 Madrid, Spain; (A.B.); (E.F.); (M.C.M.); (N.M.); (C.C.); (C.N.)
- Correspondence: ; Tel.: +34-91-394-4247
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6
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Characterizing highly fibrillated nanocellulose by modifying the gel point methodology. Carbohydr Polym 2020; 227:115340. [DOI: 10.1016/j.carbpol.2019.115340] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/09/2019] [Accepted: 09/15/2019] [Indexed: 11/17/2022]
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7
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Feng L, Liu J, Xu C, Lu W, Li D, Zhao C, Liu B, Li X, Khan S, Zheng H, Sun Y. Better understanding the polymerization kinetics of ultrasonic-template method and new insight on sludge floc characteristics research. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 689:546-556. [PMID: 31279201 DOI: 10.1016/j.scitotenv.2019.06.475] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/27/2019] [Accepted: 06/27/2019] [Indexed: 06/09/2023]
Abstract
As one of the core technologies employed in the field of sludge conditioning, flocculation has the ability to improve the sludge dewatering performance and reduce its volume and amount, which can accordingly result in lower costs in sludge transportation as well as subsequent disposal. Therefore, the development of new and high-efficiency flocculants is a hot topic in this field. The template copolymer (TPAD) of acryloyloxyethyl trimethyl ammonium chloride (DAC) and acrylamide (AM) was successfully synthesized through ultrasonic-template copolymerization using sodium-polyacrylate (NaPAA) as a template. The analysis of FTIR, 1H (13C) NMR, TG/DSC and SEM revealed that TPAD had a conspicuously significant cationic segmental structure. In addition, the results obtained from the analysis on the association constant (KM) and the kinetics of the template reaction indicated that the ultrasonic-template was a free radical initiated polymerization and the polymerization mechanism was I Zip-up (ZIP), and which once again confirmed the formation of the cationic fragment structure. This novel cationic fragment structure in TPAD greatly enhanced the ability of charge neutralization, electric patching, adsorption and bridging, thus improving the active sludge conditioning and dewatering performance (FCMC: 72.9%, SRF: 4.0 × 1012 m·kg-1, d50: 228.604 μm, Df: 2.02 at 400 r/min). The floc breakage and regeneration experiments showed that the cationic fragment structure in TPAD could make great contribution to the formation of large and dense floc structures, and these flocs were able to regenerate rapidly after breakage. Finally, it was also known that these large and compact floc structures were beneficial to the creation of more channels and voids, thereby decreasing sludge resistance (SRF) and improving sludge dewatering performance.
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Affiliation(s)
- Li Feng
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China.
| | - Junyang Liu
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China
| | - Chuang Xu
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China; State Key Laboratory of Geodesy and Earth's Dynamics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China
| | - Wencong Lu
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China
| | - Dongmei Li
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China
| | - Chuanliang Zhao
- School of Civil Engineering, Chang'an University, Xi'an 710061, China
| | - Bingzhi Liu
- College of Civil Engineering, Hunan University of Technology, Zhuzhou 412007, China
| | - Xiang Li
- School of Civil Engineering and Architecture, Chongqing University of Science and Technology, Chongqing 401331, China
| | - Sarfaraz Khan
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045,China
| | - Huaili Zheng
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045,China
| | - Yongjun Sun
- College of Urban Construction, Nanjing Tech University, Nanjing 211800, China
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Raghuwanshi VS, Garusinghe UM, Raj P, Kirby N, Hoell A, Batchelor W, Garnier G. Cationic polyacrylamide induced nanoparticles assembly in a cellulose nanofiber network. J Colloid Interface Sci 2018; 529:180-186. [PMID: 29894936 DOI: 10.1016/j.jcis.2018.06.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 06/01/2018] [Accepted: 06/04/2018] [Indexed: 12/21/2022]
Abstract
Polyacrylamides of different molecular weight, charges and dosages allow to control the retention and distribution of nanoparticles (NPs) in composites, and optimise composite properties and functionality. Our aim is to evaluate the effect of high molecular weight (13 MDa) cationic polyacrylamide (CPAM) charge and dosage on SiO2 (74 nm) NP's assembly in cellulose nanofibers composites. Engineered cellulose/SiO2 composites were investigated by SEM, SAXS and DLS. SEM images show the local area retention of NPs into the cellulose matrix. SAXS provides an average NPs distribution and inter-NPs distance over complete volume of composite. DLS gives the hydrodynamic radius of CPAM adsorbed onto SiO2 NPs in a suspension. SAXS analysis reveals a structure conformation made of spherical SiO2 NPs core of diameter 74 nm surrounded by a CPAM polyelectrolyte shell 2.5 nm thick. Surprisingly, CPAM induced assembly of SiO2 NPs with constant inter-nanoparticle distance, which is irrelevant of polymer charge density. However, NPs retention in the cellulose fibre network increases with CPAM dosage. The assembly mechanism is governed by the balance of electrostatic and steric forces following CPAM coverage onto NPs and the inter-nanoparticle CPAM bridging conformation. This maintains the constant inter-nanoparticle distance and the assembly of NPs in the cellulose network.
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Affiliation(s)
- Vikram Singh Raghuwanshi
- Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia.
| | - Uthpala Manavi Garusinghe
- Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Praveena Raj
- Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Nigel Kirby
- Australian Synchrotron, 800 Blackburn Rd., Clayton, Victoria 3168, Australia
| | - Armin Hoell
- Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
| | - Warren Batchelor
- Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Gil Garnier
- Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia.
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9
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Raj P, Batchelor W, Blanco A, de la Fuente E, Negro C, Garnier G. Effect of polyelectrolyte morphology and adsorption on the mechanism of nanocellulose flocculation. J Colloid Interface Sci 2016; 481:158-67. [PMID: 27474816 DOI: 10.1016/j.jcis.2016.07.048] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 07/19/2016] [Accepted: 07/20/2016] [Indexed: 11/18/2022]
Abstract
The effect of polyelectrolyte morphology, charge density, molecular weight and concentration on the adsorption and flocculation of Microfibrillated Cellulose (MFC) were investigated. Linear Cationic Polyacrylamide (CPAM) and Branched Polyethylenimine (PEI) of varying charge density and molecular weight were added at different dosages to MFC suspensions. The flocculation mechanisms were quantified by measuring gel point by sedimentation, and floc size, strength and reflocculation ability through Focussed Beam Reflectance Measurements. Polymer adsorption was quantified through zeta potential and adsorption measurements using polyelectrolyte titration. The flocculation mechanism of MFC is shown to be dependent on polyelectrolyte morphology. The high molecular weight branched polymer, HPEI formed rigid bridges between the MFC fibres. HPEI had low coverage and negative zeta potential at the optimum flocculation dosage, forming flocs of high strength. After breaking of flocs, total reflocculation was achieved because the high rigidity of polymer did not allow reconformation or flattening of the polyelectrolyte adsorbed on MFC surface. The lower molecular weight branched polymer, LPEI (2kDa) showed rapid total deflocculation, complete reflocculation and had maximum flocculation occurring at the point of zero charge. These characteristics correspond to a charge neutralisation mechanism. However, if the flocculation mechanism was purely charge neutralisation mechanism, the minimum gel point would be at the point of zero charge. Since this is not the case, this difference was attributed to the high polydispersity of the commercial LPEI used, allowing some bridges to be formed by the largest molecules, changing the minimum gel point. With the linear 80% charged 4MDa CPAM, bridging mechanism dominates since maximum flocculation occurred at the minimum gel point, negative zeta potential and low coverage required for maximum flocculation. Reflocculation was not possible as the long linear polymer reconformed on the MFC surface under a flat conformation. Flocculation with the linear 50% charged 13MDa CPAM happened by bridging with the minimum gel point and maximum flocculation corresponding to roughly half polyelectrolyte surface coverage on cellulose.
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Affiliation(s)
- Praveena Raj
- BioResource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton 3800, VIC, Australia; Department of Chemical Engineering, Complutense University of Madrid, Madrid 28040, Spain
| | - Warren Batchelor
- BioResource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton 3800, VIC, Australia; Department of Chemical Engineering, Complutense University of Madrid, Madrid 28040, Spain
| | - Angeles Blanco
- BioResource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton 3800, VIC, Australia; Department of Chemical Engineering, Complutense University of Madrid, Madrid 28040, Spain.
| | - Elena de la Fuente
- BioResource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton 3800, VIC, Australia; Department of Chemical Engineering, Complutense University of Madrid, Madrid 28040, Spain
| | - Carlos Negro
- BioResource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton 3800, VIC, Australia; Department of Chemical Engineering, Complutense University of Madrid, Madrid 28040, Spain
| | - Gil Garnier
- BioResource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton 3800, VIC, Australia; Department of Chemical Engineering, Complutense University of Madrid, Madrid 28040, Spain.
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10
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Shi W, Bi L, Pan G. Effect of algal flocculation on dissolved organic matters using cationic starch modified soils. J Environ Sci (China) 2016; 45:177-184. [PMID: 27372131 DOI: 10.1016/j.jes.2015.12.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 12/14/2015] [Accepted: 12/15/2015] [Indexed: 06/06/2023]
Abstract
Modified soils (MSs) are being increasingly used as geo-engineering materials for the sedimentation removal of cyanobacterial blooms. Cationic starch (CS) has been tested as an effective soil modifier, but little is known about its potential impacts on the treated water. This study investigated dissolved organic matters in the bloom water after algal removal using cationic starch modified soils (CS-MSs). Results showed that the dissolved organic carbon (DOC) could be decreased by CS-MS flocculation and the use of higher charge density CS yielded a greater DOC reduction. When CS with the charge density of 0.052, 0.102 and 0.293meq/g were used, DOC was decreased from 3.4 to 3.0, 2.3 and 1.7mg/L, respectively. The excitation-emission matrix fluorescence spectroscopy and UV254 analysis indicated that CS-MS exhibits an ability to remove some soluble organics, which contributed to the DOC reduction. However, the use of low charge density CS posed a potential risk of DOC increase due to the high CS loading for effective algal removal. When CS with the charge density of 0.044meq/g was used, DOC was increased from 3.4 to 3.9mg/L. This study suggested, when CS-MS is used for cyanobacterial bloom removal, the content of dissolved organic matters in the treated water can be controlled by optimizing the charge density of CS. For the settled organic matters, other measures (e.g., capping treatments using oxygen loaded materials) should be jointly applied after algal flocculation.
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Affiliation(s)
- Wenqing Shi
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Lei Bi
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Gang Pan
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Animal, Rural, and Environmental Sciences, Nottingham Trent University, NG25 0QF, UK.
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Raj P, Varanasi S, Batchelor W, Garnier G. Effect of cationic polyacrylamide on the processing and properties of nanocellulose films. J Colloid Interface Sci 2015; 447:113-9. [PMID: 25702868 DOI: 10.1016/j.jcis.2015.01.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 01/09/2015] [Indexed: 11/19/2022]
Abstract
The use of high molecular weight cationic polyacrylamide (CPAM) was investigated to accelerate the drainage of nanocellulose (Microfibrillated Cellulose) suspensions into films. The mechanism was quantified and optimized by measuring the gel point, the lowest solids concentration at which a continuous network is formed. The flocculation of MFC was analysed as a function of the polyelectrolyte dosage, charge density and molecular weight as well as process parameters (drainage time) and material properties. The adsorption isotherms of CPAMs on nanocellulose and their zeta potential curves were also analysed as a function of CPAM charge and dosage. Measured CPAM adsorption capacities for the 50% and 10% charged 13MDa CPAM onto MFC were 5mg/g and 8mg/g, respectively, corresponding to adsorption coverage on cellulose of 0.14mg/m(2) and 0.22mg/m(2). The floc strength and drainability of MFC suspensions were quantified with the gel point as a function of CPAM properties. For all combinations of polyelectrolyte molecular weight and charge density, the gel point of a nanocellulose suspension goes through a minimum with increasing polymer dosage. The minimum gel point was independent of the polyelectrolyte charge density at constant molecular weight. However, it reduced with decreasing CPAM molecular weight, at a constant addition rate. The drainage time of a nanocellulose suspension into a film is reduced by 2/3 by halving the gel point from 0.2 to 0.1kg/m(3); this is due to the more flocculated suspension facilitating drainage between flocs. Nanocellulose films of increased porosity also result from reducing the gel point, signifying that the more open 3D structure of the flocculated cellulose suspension is retained upon drying the 2D film cellulose film structure.
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Affiliation(s)
- Praveena Raj
- BioResource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton 3800, VIC, Australia
| | - Swambabu Varanasi
- BioResource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton 3800, VIC, Australia
| | - Warren Batchelor
- BioResource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton 3800, VIC, Australia.
| | - Gil Garnier
- BioResource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton 3800, VIC, Australia.
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Yan X, Zou C, Qin Y. A new sight of water-soluble polyacrylamide modified by β-cyclodextrin as corrosion inhibitor for X70 steel. STARCH-STARKE 2014. [DOI: 10.1002/star.201400063] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Xueling Yan
- College of Chemistry and Chemical Engineering; Southwest Petroleum University; Chengdu P. R. China
| | - Changjun Zou
- College of Chemistry and Chemical Engineering; Southwest Petroleum University; Chengdu P. R. China
| | - Yibie Qin
- College of Chemistry and Chemical Engineering; Southwest Petroleum University; Chengdu P. R. China
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13
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Effect of cationic polyacrylamide dissolution on the adsorption state of gold nanoparticles on paper and their Surface Enhanced Raman Scattering properties. Colloids Surf A Physicochem Eng Asp 2013. [DOI: 10.1016/j.colsurfa.2012.12.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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14
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Ngo YH, Li D, Simon GP, Garnier G. Effect of cationic polyacrylamides on the aggregation and SERS performance of gold nanoparticles-treated paper. J Colloid Interface Sci 2013; 392:237-246. [DOI: 10.1016/j.jcis.2012.09.080] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 09/29/2012] [Accepted: 09/29/2012] [Indexed: 12/22/2022]
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15
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Chai W, Zhang Y, Hou Y. Well-defined cationic polyacrylamides with dot-charges: synthesis via an aqueous living RAFT polymerization, characterization, and intrinsic viscosity. Polym Chem 2013. [DOI: 10.1039/c2py20808c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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