New Class of Flocculants and Coagulants


New Class of Flocculants and Coagulants

Yongjun Sun, Shengbao Zhou, Kinjal J. Shah

Coagulation is a kind of efficient water treatment method commonly used in domestic anhydrous and industrial wastewater treatment. Inorganic polymer coagulants (polyvalent metal salts) are widely used because of their low cost and ease of use. However, due to the low flocculation effectiveness and the presence of residual metal concentrations in the treated water, their application is limited. Organic synthetic flocculant has been widely used due to its higher flocculation efficiency at lower dosage. However, it has limitations in applicability due to its molecular structure which is less biodegradable and less disperse in water. Therefore, flocculants based on natural polymers have attracted extensive attention from researchers due to their advantages such as biodegradability and environmental friendliness. This paper summarizes the overview of the development of various types of flocculants that were used for industrial wastewater treatment. In addition, the characteristics and application of flocculant is reviewed with their behavior.

Coagulant, Flocculant, Coagulation, Flocculation, Organic/Inorganic Coagulants, Water Treatment

Published online 12/15/2020, 34 pages

Citation: Yongjun Sun, Shengbao Zhou, Kinjal J. Shah, New Class of Flocculants and Coagulants, Materials Research Foundations, Vol. 91, pp 219-252, 2021


Part of the book on Advances in Wastewater Treatment I

[1] H. Zheng, Y. Sun, C. Zhu, J. Guo, C. Zhao, Y. Liao, and Q. Guan, UV-initiated polymerization of hydrophobically associating cationic flocculants: Synthesis, characterization, and dewatering properties. Chem. Eng. J. 234 (2013) 318-326.
[2] Y.J. Sun, H.L. Zheng, M.Z. Tan, J.Y. Ma, W. Fan, and Y. Liao, Synthesis and Application of Hydrophobically Associating Cationic Polyacrylamide. Asian Journal of Chemistry 26 (2014) 3769-3773.
[3] H. Zheng, Y. Sun, J. Guo, F. Li, W. Fan, Y. Liao, and Q. Guan, Characterization and Evaluation of Dewatering Properties of PADB, a Highly Efficient Cationic Flocculant. Ind. Eng. Chem. Res. 53 (2014) 2572-2582.
[4] S. Li, Z. Wu, H. Tang, and J. Yang, Selective adsorption of protein on micropatterned flexible poly(ethylene terephthalate) surfaces modified by vacuum ultraviolet lithography. Appl. Surf. Sci. 258 (2012) 4222-4227.
[5] C.S. Lee, J. Robinson, and M.F. Chong, A review on application of flocculants in wastewater treatment. Process Saf. Environ. 92 (2014) 489-508.
[6] J. Wang, J. Yang, H.W. Zhang, W.S. Guo, and H.H. Ngo, Feasibility study on magnetic enhanced flocculation for mitigating membrane fouling. J. Ind. Eng. Chem. 26 (2015) 37-45.
[7] A. Nawaz, Z. Ahmed, A. Shahbaz, Z. Khan, and M. Javed, Coagulation-flocculation for lignin removal from wastewater – a review. Water Sci. Technol. 69 (2014) 1589-1597.
[8] A.K. Verma, R.R. Dash, and P. Bhunia, A review on chemical coagulation/flocculation technologies for removal of colour from textile wastewaters. J. Environ. Manage. 93 (2012) 154-168.
[9] R. Yang, H.J. Li, M. Huang, H. Yang, and A.M. Li, A review on chitosan-based flocculants and their applications in water treatment. Water Res. 95 (2016) 59-89.
[10] A.J. Harford, A.C. Hogan, D.R. Jones, and R.A. van Dam, Ecotoxicological assessment of a polyelectrolyte flocculant. Water Res. 45 (2011) 6393-6402.
[11] A.Y. Zahrim, C. Tizaoui, and N. Hilal, Coagulation with polymers for nanofiltration pre-treatment of highly concentrated dyes: A review. Desalination 266 (2011) 1-16.
[12] D.H. Bache, and R. Gregory, Flocs and separation processes in drinking water treatment: a review. J. Water Supply Res. T. 59 (2010) 16-30.
[13] F. Renault, B. Sancey, P.M. Badot, and G. Crini, Chitosan for coagulation/flocculation processes – An eco-friendly approach. Eur. Polym. J. 45 (2009) 1337-1348.
[14] F. Renault, B. Sancey, P.M. Badot, and G. Crini, Chitosan for coagulation/flocculation processes – An eco-friendly approach. Eur. Polym. J. 45 (2009) 1337-1348.
[15] Y. Sun, C. Zhu, H. Zheng, W. Sun, Y. Xu, X. Xiao, Z. You, and C. Liu, Characterization and coagulation behavior of polymeric aluminum ferric silicate for high-concentration oily wastewater treatment. Chemical Engineering Research and Design 119 (2017) 23-32.
[16] Z.Y. You, H.Y. Xu, Y.J. Sun, S.J. Zhang, and L. Zhang, Effective treatment of emulsified oil wastewater by the coagulation- flotation process. RSC Adv. 8 (2018) 40639-40646.
[17] Y. Sun, A. Chen, W. Sun, K.J. Shah, H. Zheng, and C. Zhu, Removal of Cu and Cr ions from aqueous solutions by a chitosan-based flocculant. Desalin. Water Treat. 148 (2019) 259-269.
[18] J. Ma, K. Fu, X. Fu, Q. Guan, L. Ding, J. Shi, G. Zhu, X. Zhang, S. Zhang, and L. Jiang, Flocculation properties and kinetic investigation of polyacrylamide with different cationic monomer content for high turbid water purification. Sep. Purif. Technol. 182 (2017) 134-143.
[19] X. Zhang, J. Ma, K. Fu, X. Fu, L. Ding, Q. Guan, J. Shi, and L. Jiang, Research on Synthesis of Nano Chitosan modified Polyacrylamide through Low-pressure Ultraviolet Initiation. J. Polym. Mater. 34 (2017) 129-143.
[20] J. Ma, K. Fu, J. Shi, Y. Sun, X. Zhang, and L. Ding, Ultraviolet-assisted synthesis of polyacrylamide-grafted chitosan nanoparticles and flocculation performance. Carbohyd. Polym. 151 (2016) 565-575.
[21] H. Zheng, G. Zhu, S. Jiang, T. Tshukudu, X. Xiang, P. Zhang, and Q. He, Investigations of coagulation-flocculation process by performance optimization, model prediction and fractal structure of flocs. Desalination 269 (2011) 148-156.
[22] G. Zhu, H. Zheng, Z. Zhang, T. Tshukudu, P. Zhang, and X. Xiang, Characterization and coagulation-flocculation behavior of polymeric aluminum ferric sulfate (PAFS). Chem. Eng. J. 178 (2011) 50-59.
[23] P. Luting, and W. Jinfeng, Research and progress of the preparation technologies of polyferric sulphate [J]. Industrial Water Treatment 9 (2009) 147-150.
[24] C. Liu, Y. He, F. Li, and H. Wang, Preparation of poly ferric sulfate and the application in micro-polluted raw water treatment. Journal of the Chinese Advanced Materials Society 1 (2013) 210-218.
[25] G. Zhu, H. Zheng, W. Chen, W. Fan, P. Zhang, and T. Tshukudu, Preparation of a composite coagulant: Polymeric aluminum ferric sulfate (PAFS) for wastewater treatment. Desalination 285 (2012) 315-323.
[26] Z. Yang, X. Lu, B. Gao, Y. Wang, Q. Yue, and T. Chen, Fabrication and characterization of poly (ferric chloride)-polyamine flocculant and its application to the decolorization of reactive dyes. J. Mater. Sci. 49 (2014) 4962-4972.
[27] X. Sheng, Study on Poly Ferric Chloride from Steel Pickling Acid Waste. Shandong Chemical Industry 6 (2012) 10.
[28] T. Tshukudu, H.L. Zheng, X.B. Hua, J. Yang, M.Z. Tan, J.Y. Ma, Y.J. Sun, and G.C. Zhu, Response surface methodology approach to optimize coagulation-flocculation process using composite coagulants. Korean J. Chem. Eng. 30 (2013) 649-657.
[29] W. Zhang, L. Yao, J. Ma, and D. Li, Study on Preparation and Flocculation Properties of Inorganic Polymer Flocculant Polyferric Silicate Sulfate (PFSS), 2010 4th International Conference on Bioinformatics and Biomedical Engineering, IEEE, Chengdu, 2010, pp. 1-4.
[30] T. Tshukudu, H. Zheng, and J. Yang, Optimization of Coagulation with PFS-PDADMAC Composite Coagulants Using the Response Surface Methodology Experimental Design Technique. Water Environ. Res. 85 (2013) 456-465.
[31] T. Tshukudu, H. Zheng, X. Hua, J. Yang, M. Tan, J. Ma, Y. Sun, and G. Zhu, Response surface methodology approach to optimize coagulation-flocculation process using composite coagulants. Korean J. Chem. Eng. 30 (2013) 649-657.
[32] J. Shi, Q. Liu, and D.S. Wang, Studies on the realationship between the speciation distribution and Si/Fe ratio of poly-silica-ferric-chloride, Advanced Materials Research, Trans Tech Publ, Wu Han, 2011, pp. 1339-1342.
[33] C. Jian, Research Progress of Inorganic Polymer Flocculants. Journal of Langfang Teachers University (Natural Science Edition) 16 (2016) 70-72.
[34] H.L. Zheng, J.Y. Ma, C.J. Zhu, Z. Zhang, L.W. Liu, Y.J. Sun, and X.M. Tang, Synthesis of anion polyacrylamide under UV initiation and its application in removing dioctyl phthalate from water through flocculation process. Sep. Purif. Technol. 123 (2014) 35-44.
[35] L. Zhang, Y. Zeng, and Z. Cheng, Removal of heavy metal ions using chitosan and modified chitosan: A review. J. Mol. Liq. 214 (2016) 175-191.
[36] R. Wang, K. Sun, J. Wang, Y. He, P. Song, and Y. Xiong, Preparation and Application of Natural Polymer/Hydroxyapatite Composite. Prog. Chem. 28 (2016) 885-895.
[37] C. Feng, X. Ge, D. Wang, and H. Tang, Effect of aging condition on species transformation in polymeric Al salt coagulants. Colloid. Surface. A. 379 (2011) 62-69.
[38] C. Feng, H. Tang, and D. Wang, Differentiation of hydroxyl-aluminum species at lower OH/Al ratios by combination of 27Al NMR and Ferron assay improved with kinetic resolution. Colloid. Surface. A. 305 (2007) 76-82.
[39] B. Shi, G. Li, D. Wang, C. Feng, and H. Tang, Removal of direct dyes by coagulation: The performance of preformed polymeric aluminum species. J. Hazard. Mater. 143 (2007) 567-574.
[40] B. Shi, Q. Wei, D. Wang, Z. Zhu, and H. Tang, Coagulation of humic acid: The performance of preformed and non-preformed Al species. Colloid. Surface. A. 296 (2007) 141-148.
[41] B. Shi, G. Li, D. Wang, and H. Tang, Separation of Al-13 from polyaluminum chloride by sulfate precipitation and nitrate metathesis. Sep. Purif. Technol. 54 (2007) 88-95.
[42] C. Ye, D. Wang, B. Shi, J. Yu, J. Qu, M. Edwards, and H. Tang, Alkalinity effect of coagulation with polyaluminum chlorides: Role of electrostatic patch. Colloid. Surface. A. 294 (2007) 163-173.
[43] X. Wu, X. Ge, D. Wang, and H. Tang, Distinct coagulation mechanism and model between alum and high Al-13-PACl. Colloid. Surface. A. 305 (2007) 89-96.
[44] H. Tang, F. Xiao, and D. Wang, Speciation, stability, and coagulation mechanisms of hydroxyl aluminum clusters formed by PACl and alum: A critical review. Adv. Colloid Interfac. 226 (2015) 78-85.
[45] X. Wu, C. Ye, D. Wang, X. Ge, and H. Tang, Effect of speciation transformation on the coagulation behavior of Al-13 and Al-13 aggregates. Water Sci. Technol. 59 (2009) 815-822.
[46] H. Liu, D. Wang, M. Wang, H. Tang, and M. Yang, Effect of pre-ozonation on coagulation with IPF-PACls: Role of coagulant speciation. Colloid. Surface. A. 294 (2007) 111-116.
[47] Z. Bi, C. Feng, D. Wang, X. Ge, and H. Tang, Transformation of planar Mogel Al-13 to epsilon Keggin Al-13 in dissolution process. Colloid. Surface. A. 407 (2012) 91-98.
[48] J. Cao, Z. Wu, S. Li, H. Tang, and Q. Mei, Site-selective adsorption of protein induced by a metal pattern on a poly(ethylene terephthalate) surface. Colloid. Surface. B. 111 (2013) 418-422.
[49] C. Feng, Q. Wei, S. Wang, B. Shi, and H. Tang, Speciation of hydroxyl-Al polymers formed through simultaneous hydrolysis of aluminum salts and urea. Colloid. Surface. A. 303 (2007) 241-248.
[50] T. Li, Z. Zhu, D. Wang, C. Yao, and H. Tang, The strength and fractal dimension characteristics of alum-kaolin flocs. Int. J. Miner. Process. 82 (2007) 23-29.
[51] Y. Wang, H. Zhou, F. Yu, B. Shi, and H. Tang, Fractal adsorption characteristics of complex molecules on particles – A case study of dyes onto granular activated carbon (GAC). Colloid. Surface. A. 299 (2007) 224-231.
[52] T. Li, D. Wang, B. Zhang, H. Liu, and H. Tang, Morphological characterization of suspended particles under wind-induced disturbance in Taihu Lake, China. Environ. Monit. Assess. 127 (2007) 79-86.
[53] X. Wu, D. Wang, X. Ge, and H. Tang, Coagulation of silica microspheres with hydrolyzed Al(III)-Significance of Al-13 and Al-13 aggregates. Colloid. Surface. A. 330 (2008) 72-79.
[54] D. Wang, J. Gregory, and H. Tang, Mechanistic difference of coagulation of kaolin between PACl and cationic polyelectrolytes: A comparative study on zone 2 coagulation. Dry. Technol. 26 (2008) 1060-1067.
[55] C. Feng, S. Zhao, Z. Bi, D. Wang, and H. Tang, Speciation of prehydrolyzed Al salt coagulants with electrospray ionization time-of-flight mass spectrometry and Al-27 NMR spectroscopy. Colloid. Surface. A. 392 (2011) 95-102.
[56] Y. Sun, M. Ren, W. Sun, X. Xiao, Y. Xu, H. Zheng, H. Wu, Z. Liu, and H. Zhu, Plasma-induced synthesis of chitosan-g-polyacrylamide and its flocculation performance for algae removal. Environ. Technol. 40 (2017) 954-968.
[57] Y. Sun, J. Liu, W. Sun, H. Zheng, and K.J. Shah, An alternative strategy for enhanced algae removal by cationic chitosan-based flocculants. Desalin. Water Treat. 167 (2019) 13-26.
[58] X. Xiao, Y. Sun, W. Sun, H. Shen, H. Zheng, Y. Xu, J. Zhao, H. Wu, and C. Liu, Advanced treatment of actual textile dye wastewater by Fenton-flocculation process. The Canadian Journal of Chemical Engineering 95 (2017) 1245-1252.
[59] L. Feng, J. Liu, C. Xu, W. Lu, D. Li, C. Zhao, B. Liu, X. Li, S. Khan, H. Zheng, and Y. Sun, Better understanding the polymerization kinetics of ultrasonic-template method and new insight on sludge floc characteristics research. Sci. Total Environ. 689 (2019) 546-556.
[60] S. Zhang, H. Zheng, X. Tang, Y. Sun, Y. Wu, X. Zheng, and Q. Sun, Evaluation a self-assembled anionic polyacrylamide flocculant for the treatment of hematite wastewater: Role of microblock structure. J. Taiwan Inst. Chem. E. 95 (2019) 11-20.
[61] L. Feng, J. Liu, C. Xu, W. Lu, D. Li, C. Zhao, B. Liu, X. Li, S. Khan, H. Zheng, and Y. Sun, Better understanding the polymerization kinetics of ultrasonic-template method and new insight on sludge floc characteristics research. The Science of the total environment 689 (2019) 546-556.
[62] Y. Sun, K.J. Shah, W. Sun, and H. Zheng, Performance evaluation of chitosan-based flocculants with good pH resistance and high heavy metals removal capacity. Sep. Purif. Technol. 215 (2019) 208-216.
[63] Y. Sun, W. Sun, K.J. Shah, P. Chiang, and H. Zheng, Characterization and flocculation evaluation of a novel carboxylated chitosan modified flocculant by UV initiated polymerization. Carbohyd. Polym. 208 (2019) 213-220.
[64] K. Xu, Y. Liu, Y. Wang, Y. Tan, X. Liang, C. Lu, H. Wang, X. Liu, and P. Wang, A novel poly (acrylic acid-co-acrylamide)/diatomite composite flocculant with outstanding flocculation performance. Water Sci. Technol. 72 (2015) 889-895.
[65] J. Li, J. Li, X. Liu, Z. Du, and F. Cheng, Effect of silicon content on preparation and coagulation performance of poly-silicic-metal coagulants derived from coal gangue for coking wastewater treatment. Sep. Purif. Technol. 202 (2018) 149-156.
[66] X. Xiong, L. Wei, X.U. Xia, and D. Yan, Synthesis of Polymeric Hybrid Flocculant PSAF-CPAM and its Phosphorus Removal in Printing and Dyeing Wastewater. Industrial Safety and Environmental Protection 6 (2018) 21.
[67] Y. Sun, H. Zheng, M. Tan, Y. Wang, X. Tang, L.I. Feng, and X. Xiang, Synthesis and characterization of composite flocculant PAFS-CPAM for the treatment of textile dye wastewater. J. Appl. Polym. Sci. 131 (2014) 156-161.
[68] H. Salehizadeh, N. Yan, and R. Farnood, Recent advances in polysaccharide bio-based flocculants. Biotechnol. Adv. 36 (2018) 92-119.
[69] M. Sillanpaa, M.C. Ncibi, A. Matilainen, and M. Vepsalainen, Removal of natural organic matter in drinking water treatment by coagulation: A comprehensive review. Chemosphere 190 (2018) 54-71.
[70] J. Desbrières, and E. Guibal, Chitosan for wastewater treatment. Polym. Int. 67 (2018) 7-14.
[71] L.Y. Chai, Q.Z. Li, Q.W. Wang, and X. Yan, Solid-liquid separation: an emerging issue in heavy metal wastewater treatment. Environ. Sci. Pollut. R. 25 (2018) 17250-17267.
[72] P. Kanmani, J. Aravind, M. Kamaraj, P. Sureshbabu, and S. Karthikeyan, Environmental applications of chitosan and cellulosic biopolymers: A comprehensive outlook. Bioresource Technol. 242 (2017) 295-303.
[73] Q. Tang, J. Wu, J. Lin, Q. Li, and S. Fan, Two-step synthesis of polyacrylamide/polyacrylate interpenetrating network hydrogels and its swelling/deswelling properties. J. Mater. Sci. 43 (2008) 5884-5890.
[74] A. Pinotti, and N. Zaritzky, Effect of aluminum sulfate and cationic polyelectrolytes on the destabilization of emulsified wastes. Waste Manage. 21 (2001) 535-542.
[75] M.X. Xue, B.Y. Gao, X. Xu, and W. Song, Polyamidine as a New-Style Coagulant Aid for Dye Wastewater Treatment and its Floc Characteristics, Materials Science Forum, Trans Tech Publ, Singapore, 2018, pp. 930-940.
[76] K. Zeng, W. Qin, F. Jiao, M. He, and L. Kong, Treatment of mine drainage generated by lead-zinc concentration plant. J. Cent. South Univ. 21 (2014) 1453-1460.
[77] K.E. Lee, T.T. Teng, N. Morad, B.T. Poh, and M. Mahalingam, Flocculation activity of novel ferric chloride-polyacrylamide (FeCl3-PAM) hybrid polymer. Desalination 266 (2011) 108-113.
[78] Q. YUE, Y. LI, B. GAO, Z. YANG, and X. ZOU, Study on the inverse emulsion polymerization of PDMDAAC-AM [J]. Journal of Shandong University (Natural Science) 6 (2004) 120-125.
[79] B. Gao, Y. Wang, Q. Yue, J. Wei, and Q. Li, Color removal from simulated dye water and actual textile wastewater using a composite coagulant prepared by ployferric chloride and polydimethyldiallylammonium chloride. Sep. Purif. Technol. 54 (2007) 157-163.
[80] J.C. Wei, B.Y. Gao, Q.Y. Yue, Y. Wang, and L. Lu, Performance and mechanism of polyferric-quaternary ammonium salt composite flocculants in treating high organic matter and high alkalinity surface water. J. Hazard. Mater. 165 (2009) 789-795.
[82] C.J. Ridgway, and P.A. Gane, Size-selective absorption and adsorption in anionic pigmented porous coating structures: case study cationic starch polymer versus nanofibrillated cellulose. Cellulose 20 (2013) 933-951.
[83] F. Pereira, K.S. Sousa, G. Cavalcanti, M.G. Fonseca, A.G. de Souza, and A. Alves, Chitosan-montmorillonite biocomposite as an adsorbent for copper (II) cations from aqueous solutions. Int. J. Biol. Macromol. 61 (2013) 471-478.
[84] Y. Sun, S. Zhou, S. Pan, S. Zhu, Y. Yu, and H. Zheng, Performance evaluation and optimization of flocculation process for removing heavy metal. Chem. Eng. J. 385 (2020) 123911.
[85] Y. Sun, S. Zhou, W. Sun, S. Zhu, and H. Zheng, Flocculation activity and evaluation of chitosan-based flocculant CMCTS-g-P(AM-CA) for heavy metal removal. Sep. Purif. Technol. 241 (2020) 116737.
[86] P. Wu, J. Yi, L. Feng, X. Li, Y. Chen, Z. Liu, S. Tian, S. Li, S. Khan, and Y. Sun, Microwave assisted preparation and characterization of a chitosan based flocculant for the application and evaluation of sludge flocculation and dewatering. Int. J. Biol. Macromol. 155 (2020) 708-720.
[87] Y. Sun, A. Chen, W. Sun, K.J. Shah, H. Zheng, and C. Zhu, Removal of Cu and Cr ions from aqueous solutions by a chitosan based flocculant. Desalin. Water Treat. 148 (2019) 259-269.
[88] H. Wei, B.Q. Gao, J. Ren, A.M. Li, and H. Yang, Coagulation/flocculation in dewatering of sludge: A review. Water Res. 143 (2018) 608-631.
[89] Y. Sun, A. Chen, S. Pan, W. Sun, C. Zhu, K.J. Shah, and H. Zheng, Novel chitosan-based flocculants for chromium and nickle removal in wastewater via integrated chelation and flocculation. J. Environ. Manage. 248 (2019) 109241.
[90] L. Chen, Y. Sun, W. Sun, K.J. Shah, Y. Xu, and H. Zheng, Efficient cationic flocculant MHCS-g-P(AM-DAC) synthesized by UV-induced polymerization for algae removal. Sep. Purif. Technol. 210 (2019) 10-19.
[91] Z. You, C. Zhuang, Y. Sun, S. Zhang, and H. Zheng, Efficient Removal of TiO2 Nanoparticles by Enhanced Flocculation-Coagulation. Ind. Eng. Chem. Res. 58 (2019) 14528-14537.
[92] S. Jia, Z. Yang, W. Yang, T. Zhang, S. Zhang, X. Yang, Y. Dong, J. Wu, and Y. Wang, Removal of Cu (II) and tetracycline using an aromatic rings-functionalized chitosan-based flocculant: enhanced interaction between the flocculant and the antibiotic. Chem. Eng. J. 283 (2016) 495-503.
[93] H. Ge, H. Chen, and S. Huang, Microwave preparation and properties of O‐crosslinked maleic acyl chitosan adsorbent for Pb2+ and Cu2+. J. Appl. Polym. Sci. 125 (2012) 2716-2723.
[94] M. Sugimoto, M. Morimoto, H. Sashiwa, H. Saimoto, and Y. Shigemasa, Preparation and characterization of water-soluble chitin and chitosan derivatives. Carbohyd. Polym. 36 (1998) 49-59.
[95] X. Huang, H. Bu, G. Jiang, and M. Zeng, Cross-linked succinyl chitosan as an adsorbent for the removal of Methylene Blue from aqueous solution. Int. J. Biol. Macromol. 49 (2011) 643-651.
[96] J. Ma, K. Fu, J. Shi, Y. Sun, X. Zhang, and L. Ding, Ultraviolet-assisted synthesis of polyacrylamide-grafted chitosan nanoparticles and flocculation performance. Carbohyd. Polym. 151 (2016) 565-575.
[97] C. Fan, K. Li, Y. He, Y. Wang, X. Qian, and J. Jia, Evaluation of magnetic chitosan beads for adsorption of heavy metal ions. Sci. Total Environ. 627 (2018) 1396-1403.
[98] T. Lou, X. Wang, G. Song, and G. Cui, Synthesis and flocculation performance of a chitosan-acrylamide-fulvic acid ternary copolymer. Carbohyd. Polym. 170 (2017) 182-189.
[99] L. Chen, H. Zhu, Y. Sun, P. Chiang, W. Sun, Y. Xu, H. Zheng, and K.J. Shah, Characterization and sludge dewatering performance evaluation of the photo-initiated cationic flocculant PDD. J. Taiwan Inst. Chem. E. 93 (2018) 253-262.
[100] W. Sun, H. Zhu, Y. Sun, L. Chen, Y. Xu, and H. Zheng, Enhancement of waste-activated sludge dewaterability using combined Fenton pre-oxidation and flocculation process. Desalin. Water Treat. 126 (2018) 314-323.
[101] X. Lu, Y. Xu, W. Sun, Y. Sun, and H. Zheng, UV-initiated synthesis of a novel chitosan-based flocculant with high flocculation efficiency for algal removal. Sci. Total Environ. 609 (2017) 410-418.
[102] Y. Sun, C. Zhu, W. Sun, Y. Xu, X. Xiao, H. Zheng, H. Wu, and C. Liu, Plasma-initiated polymerization of chitosan-based CS-g-P(AM-DMDAAC) flocculant for the enhanced flocculation of low-algal-turbidity water. Carbohyd. Polym. 164 (2017) 222-232.
[103] M. Tang, C. Zhu, Y. Sun, Y. Xu, H. Zheng, X. Xiao, W. Sun, H. Wu, and C. Liu, Preparation of polymeric aluminum ferric silicate for the pre-treatment of oily wastewater through response surface method. Desalin. Water Treat. 65 (2017) 284-293.
[104] V. Haack, T. Heinze, G. Oelmeyer, and W.M. Kulicke, Starch derivatives of high degree of functionalization, 8. Synthesis and flocculation behavior of cationic starch polyelectrolytes. Macromol. Mater. Eng. 287 (2002) 495-502.<495::AID-MAME495>3.0.CO;2-K
[105] Z. Liu, M. Huang, A. Li, and H. Yang, Flocculation and antimicrobial properties of a cationized starch. Water Res. 119 (2017) 57-66.
[106] M. Huang, Z. Liu, A. Li, and H. Yang, Dual functionality of a graft starch flocculant: Flocculation and antibacterial performance. J. Environ. Manage. 196 (2017) 63-71.
[107] W. Sun, G. Ma, Y. Sun, Y. Liu, N. Song, Y. Xu, and H. Zheng, Effective treatment of high phosphorus pharmaceutical wastewater by chemical precipitation. The Canadian Journal of Chemical Engineering 95 (2017) 1585-1593.
[108] S. Mansouri, R. Khiari, F. Bettaieb, A.A. El-Gendy, and F. Mhenni, Synthesis and characterization of carboxymethyl cellulose from tunisian vine stem: study of water absorption and retention capacities. J. Polym. Environ. 23 (2015) 190-198.
[109] A. Shaabani, A. Rahmati, and Z. Badri, Sulfonated cellulose and starch: New biodegradable and renewable solid acid catalysts for efficient synthesis of quinolines. Catal. Commun. 9 (2008) 13-16.
[110] S. Hokkanen, E. Repo, T. Suopajärvi, H. Liimatainen, J. Niinimaa, and M. Sillanpää, Adsorption of Ni (II), Cu (II) and Cd (II) from aqueous solutions by amino modified nanostructured microfibrillated cellulose. Cellulose 21 (2014) 1471-1487.
[111] T. Suopajärvi, H. Liimatainen, M. Karjalainen, H. Upola, and J. Niinimäki, Lead adsorption with sulfonated wheat pulp nanocelluloses. Journal of Water Process Engineering 5 (2015) 136-142.
[112] Y. Sun, M. Ren, C. Zhu, Y. Xu, H. Zheng, X. Xiao, H. Wu, T. Xia, and Z. You, UV-Initiated Graft Copolymerization of Cationic Chitosan-Based Flocculants for Treatment of Zinc Phosphate-Contaminated Wastewater. Ind. Eng. Chem. Res. 55 (2016) 10025-10035.