Co-reporter:Yi Liao;Wenwen Xue;Li Qian;Yongjun Sun;Li Dai
Industrial & Engineering Chemistry Research July 9, 2014 Volume 53(Issue 27) pp:11193-11203
Publication Date(Web):2017-2-22
DOI:10.1021/ie5016987
Two cationic polyacrylamides, PAA and PAD, were synthesized for sludge dewatering. The advanced instruments such as 1H NMR, FTIR, and SEM were used to characterize the two copolymers. Their hydrophobic association properties in water were investigated by viscosimetry as well as the dewatering performance studied by the sludge dewatering experiment. The results showed that the optimum conditions for preparation of PAA were that the initiator concentration, urea concentration, molar ratio of AODBAC to AM, and irradiation time were 0.3‰, 1.0%, 10:90, and 60 min, respectively. Also, it was found that PAA had a stronger hydrophobic interaction with a lower intrinsic viscosity and longer dissolution time as well as a better dewatering performance. Furthermore, the charge neutralization and bridging effects were found to contribute much to the sludge dewatering by PAA in which the dewatering performance was able to be enhanced further by the hydrophobic interaction.
Co-reporter:Yong Liao;Xiaomin Tang;Qingqing Yang;Wei Chen;Bingzhi Liu;Chuanliang Zhao;Jun Zhai
RSC Advances (2011-Present) 2017 vol. 7(Issue 32) pp:19856-19862
Publication Date(Web):2017/03/31
DOI:10.1039/C7RA00232G
Algae and algae organic matter (AOM) are not the sole pollutants in algae-polluted water. Other pollutants such as colloidal particles and natural organic matter should be simultaneously removed and might influence the treatment of algae and AOM. A new polymeric zinc–ferric–silicate–sulfate (PZFSiS) coagulant was prepared, and the relationship between its structure and performance in the treatment of humic acid (HA)/algae-polluted water was discussed. PZFSiS coagulants prepared under different conditions had different distributions of Fe(III) species. The coagulant possessing the highest Feb content was able to treat turbidity and HA well. As a copolymer of Fe(III), Zn(II) and Si(IV), PZFSiS had a positive charge in water and thus neutralized the negative surface charges of pollutants. The adsorption of hydroxyl polymer formed by Fe/Zn during the hydrolysis process contributed to the removal of organic matter. The dosage of PZFSiS and pH significantly influenced pollutant removal. Colloidal particles in the water competed with the organic matter, markedly decreasing the removal efficiency of organic matter by coagulation.
Co-reporter:Yuhao Zhou;Baoyu Gao;Yingpeng Gua;Xiang Lia;Bingzhi Liu;Andrea Navarro Jiménez
RSC Advances (2011-Present) 2017 vol. 7(Issue 78) pp:49329-49329
Publication Date(Web):2017/10/20
DOI:10.1039/C7RA90100C
Correction for ‘Waste activated sludge (WAS) dewatering properties of an original hydrophobically modified polyacrylamide containing a cationic microblock structure’ by Yuhao Zhou et al., RSC Adv., 2017, 7, 28733–28745.
Co-reporter:Yuhao Zhou;Baoyu Gao;Yingpeng Gu;Xiang Li;Bingzhi Liu;Andrea Mavarro Jiménez
RSC Advances (2011-Present) 2017 vol. 7(Issue 46) pp:28733-28745
Publication Date(Web):2017/05/30
DOI:10.1039/C7RA02939J
Chemical conditioning, as one of the core technologies used for the dewatering pretreatment of sludge, can efficiently improve the dewaterability of WAS and hence reduce the expense of the transportation and disposal of WAS. Cationic polyacrylamide has been widely utilized as a chemical conditioner owing to its high performance and economic advantages. However, high-performance and economical flocculants are still needed. In this study, a novel hydrophobically associating polyacrylamide, which was denoted as TPADL and contained a cationic microblock structure synthesized by a UV-initiated template copolymerization technique, was employed in a dewatering test on WAS. The chemical composition of TPADL was confirmed via hydrogen nuclear magnetic resonance (1H NMR) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. Moreover, 1H NMR spectroscopy demonstrated a highly concentrated distribution of cations on the main chain. Furthermore, thermogravimetric analysis (TGA) was utilized to investigate the thermal stability of TPADL, and its apparent viscosity was also measured to evaluate its rheological characteristics. Dewatering tests found that the TPADL flocculant exerted a synergistic function owing to the cationic microblock structure and hydrophobic association and exhibited superior dewatering performance in comparison with normal random cationic polyacrylamide (CPAM). The filter cake moisture content (FCMC) and specific resistance to filtration (SRF) reached 64.98% and 1.3 × 1012 m kg−1, respectively, for TPADL at the optimal dosage of 1.5 mg g−1 dry solids of WAS (calculated value). The floc size distribution revealed that hydrophobic association remarkably increased the floc size owing to enhancements in bridging absorption ability, whereas the cationic microblock structure helped form a denser and more compact floc structure, and the higher charge neutralization ability enabled an increase in floc strength. In addition, the synergistic function significantly improved the regeneration ability of flocs. Scanning electron microscopy (SEM) analysis indicated that the stronger floc structure could act as a skeleton to form pores and a channel-like structure, which made filter cake a favorable draining medium for the release of water and thus contributed to an increase in dewaterability. This study provided an analysis for the development of high-performance and economic flocculants by a combination of the controllable concentrated distribution of cations and hydrophobic association.
Co-reporter:Bincheng Xu;Chaofan Zheng;Yili Wang;Chun Zhao;Chuanliang Zhao;Shixin Zhang
RSC Advances (2011-Present) 2017 vol. 7(Issue 74) pp:47029-47037
Publication Date(Web):2017/10/02
DOI:10.1039/C7RA06810G
Novel polymer-grafted magnetic microspheres (GMMs) were prepared by graft polymerization of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and acrylic acid (AA) onto the surface of chitosan/magnetite composite microspheres (MMs). The magnetic microspheres were fully characterized and then applied to the adsorption of a cationic dye (methylene blue, MB) from aqueous solutions. Results show that the adsorption capacity of GMMs was notably enhanced compared with MMs. Furthermore, the effects of initial solution pH, contact time and initial concentration on MB adsorption by GMMs were systematically investigated. The adsorption kinetics and adsorption isotherms are well described by pseudo-second-order kinetic model and Langmuir isotherm model respectively, suggesting the adsorption is a homogeneous monolayer adsorption. The maximum MB adsorption capacity by GMMs is found to be 925.9 mg g−1 at 298.15 K and initial solution pH 9.0, as determined from the Langmuir isotherm. The MB-loaded GMMs can be rapidly separated and effectively regenerated at pH 2.0.
Co-reporter:Xiang Li, Huaili Zheng, Baoyu Gao, Yongjun Sun, Bingzhi Liu, Chuanliang Zhao
Chemosphere 2017 Volume 167(Volume 167) pp:
Publication Date(Web):1 January 2017
DOI:10.1016/j.chemosphere.2016.09.046
•A cationic polyacrylamide (CPAM) with microblock structure was synthesized through UV-initiated template copolymerization.•All of the instrumental analysis results confirmed the micro block structure of the template CPAM.•Reaction kinetics revealed I (ZIP) template polymerization mechanism of this reaction.•The template copolymer showed excellent sludge dewatering performance.Flocculation as the core technology of sludge pretreatment can improve the dewatering performance of sludge that enables to reduce the cost of sludge transportation and the subsequent disposal costs. Therefore, synthesis of high-efficiency and economic flocculant is remarkably desired in this field. This study presents a cationic polyacrylamide (CPAM) flocculant with microblock structure synthesized through ultraviolet (UV)-initiated template copolymerization by using acrylamide (AM) and methacrylamido propyl trimethyl ammonium chloride (MAPTAC) as monomers, sodium polyacrylate (PAAS) as template, and 2,2'-azobis [2-(2-imidazolin-2-yl) propane] dihydrochloride (VA-044) as photoinitiator. The microblock structure of the CPAM was observed through nuclear magnetic resonance (1H NMR and 13C NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) analyses. Furthermore, thermogravimetric/differential scanning calorimetry (TG/DSC) analysis was used to evaluate its thermal decomposition property. The copolymerization mechanism was investigated through the determination of the binding constant MK and study on polymerization kinetics. Results showed that the copolymerization was conducted in accordance with the I (ZIP) template polymerization mechanism, and revealed the coexistence of bimolecular termination free-radical reaction and mono-radical termination in the polymerization process. Results of sludge dewatering tests indicated the superior flocculation performance of microblock flocculant than random distributed CPAM. The residual turbidity, filter cake moisture content, and specific resistance to filtration reached 9.37 NTU, 68.01%, and 6.24 (1012 m kg−1), respectively, at 40 mg L−1 of template poly(AM-MAPTAC) and pH 6.0. Furthermore, all flocculant except commercial CPAM showed a wide scope of pH application.Download high-res image (170KB)Download full-size image
Co-reporter:
Journal of Applied Polymer Science 2017 Volume 134(Issue 11) pp:
Publication Date(Web):2017/03/15
DOI:10.1002/app.44500
ABSTRACTInorganic/organic composite coagulants have drawn a wide attention through the years owing to its superior coagulation behaviors. In this study, polyaluminum chloride (PAC)/polyacrylamide (PAM) composite coagulant was synthesized by ultraviolet (UV) irradiation by using PAC and acrylamide (AM) as raw materials, urea as a solubilizer, and 2,2′-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride (VA-044) as an initiator. The effect of total monomer mass fraction, solubilizer dosage and initiator dosage on the viscosity and molecular weight of PAC/PAM composite coagulant was discussed. The results suggest that the composite coagulant with high polymerization degree, intrinsic viscosity of 1483 mL/g and molecular weight of 7.38 million, could be obtained when the total monomer mass fraction of 40%, urea dosage of 1.5% and initiator dosage of 0.6% are chosen in the preparation. It is a potential preparation method of composite coagulant with short preparation time and high preparation efficiency. Fourier transform infrared spectrum and 1H nuclear magnetic resonance spectroscopy represent that the coagulant for polyaluminum chloride and polypropylene are copolymer. Thermal gravimetric analysis describes the high thermal stability of composite coagulant. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44500.
Co-reporter:Xiang Li, Huaili Zheng, Yili Wang, Yongjun Sun, Bincheng Xu, Chuanliang Zhao
Chemical Engineering Journal 2017 Volume 319(Volume 319) pp:
Publication Date(Web):1 July 2017
DOI:10.1016/j.cej.2017.02.147
•A novel enhanced sterilization chitosan-based flocculants (CTS-g-PAMA) was successfully synthesized.•Morphology analysis and solubility experiments indicated grafting of PAMA can help to improve the specific surface area and water solubility of CTS.•CTS-g-PAMA showed excellent flocculation and sterilization in both kaolin and Escherichia coli suspension.•The sterilization effect of CTS-g-PAMA was essentially bactericidal, not just antibacterial.Modified natural polymer flocculants has been the focus of research in environmental engineering field. Natural large molecular compound, chitosan (CTS) with many functional amino and hydroxyl groups can be easily modified to enhance its original functions. This work presents an environmentally friendly chitosan-based cationic polyacrylamide flocculants (CTS-g-PAMA) with enhanced function of sterilization and flocculation. CTS-g-PAMA was synthesized through Ultraviolet (UV)-initiated copolymerization. Structure characterization of FTIR, 1H NMR, XRD and UV spectrum confirmed the successful grafting of AM and MAPTAC. Scanning electron microscopy (SEM) analysis results showed that CTS-g-PAMA exhibited a porous structure with a prodigious surface area. CTS-g-PAMA was then applied to treat a series of simulated waste water containing kaolin or Escherichia coli. Flocculation tests indicated that CTS-g-PAMA not only showed excellent flocculation effect but also showed high sterilization capability. A series of ONP concentration measurement tests through UV spectra analysis and 3D EEM analysis of suspension before and after flocculation were conducted to study sterilization mechanism, and results revealed the sterilization effect of CTS-g-PAMA was essentially bactericidal, not just antibacterial.Download high-res image (109KB)Download full-size image
Co-reporter:Xiang Li, Huaili Zheng, Baoyu Gao, Chun Zhao, Yongjun Sun
Separation and Purification Technology 2017 Volume 187(Volume 187) pp:
Publication Date(Web):31 October 2017
DOI:10.1016/j.seppur.2017.06.035
•An acid and alkali resistant cationic flocculants (PAMA) was synthesized and characterized.•The synthesis conditions of PAMA was studied systematically.•PAMA was an efficient flocculants for sludge dewatering and showed strong acid and alkali resistance.Cationic polyacrylamide (CPAM) has been the focus of research in environmental engineering field, particularly in sludge dewatering. However, poor stability of the existing cationic polyacrylamide has limited its application. In the face of the current complex sewage/sludge environment, CPAM with high efficiency, good stability and economy is remarkably desired in this field. In this study, a CPAM (PAMA) with high acid and alkali resistance was synthesized through copolymerization of acrylamide (AM) and methacrylamido propyl trimethyl ammonium chloride (MAPTAC) under ultraviolet (UV) radiation. The structure, morphology as well as the thermal decomposition property were analyzed through instrumental analysis. Furthermore, influencing factors of the copolymerization reaction were investigated and discussed in detail. The dewatering performance of PAMA was also evaluated by measuring the supernatant residual turbidity (RT), moisture content of the filter cake (FCMC), and specific resistance to filtration of the sludge (SRF). The RT, FCMC, and SRF reached 4.70 NTU, 71%, and 3.94 (1012 m Kg−1), respectively, at 40 mg L−1 of PAMA-25-15.1 and pH of 6.0. Furthermore, these indices did not increase with the pH changes of the original sludge, and which indicated a high acid and alkali resistance of PAMA.Download high-res image (182KB)Download full-size image
Co-reporter:Wei Chen, Huaili Zheng, Qingqing Guan, Houkai Teng, Chuanliang Zhao, and Chun Zhao
Industrial & Engineering Chemistry Research 2016 Volume 55(Issue 10) pp:2892-2902
Publication Date(Web):February 22, 2016
DOI:10.1021/acs.iecr.5b04207
A new flocculant with cationic microblock structure was prepared by using template polymerization. Acrylamide (AM) and acryloyloxyethyltrimethylammonium chloride (DAC) were used as monomers, and sodium polyacrylate was used as the template. The reactivity ratio, 1H NMR, 13C NMR, and thermogravimetric analysis were employed to characterize the structural properties of products. Results show that, with the addition of the template, the reactivity ratio of DAC increased, whereas that of AM decreased. Evident microblock structure was synthesized in copolymers when the molar ratio of template to DAC was 1.0. Activated sludge dewatering experiment results reveal that the cationic microblocky flocculant exhibited superior dewatering efficiency, and a low moisture content of 71% and a specific resistance of 1.99 × 1012 m·kg–1 were acquired at pH 7.0 and a 40 mg L–1 dosage. The enhanced charge neutralization and bridging effect of the cationic microblocky flocculant contributed to the formation of floc with a large size and compact structure.
Co-reporter:Wei Chen;Jinsong Guo;Fengting Li
Water, Air, & Soil Pollution 2016 Volume 227( Issue 3) pp:
Publication Date(Web):2016 March
DOI:10.1007/s11270-016-2766-6
In this study, a novel composite coagulant polyferric titanium sulfate (PFTS) was synthesized and the kaolin-fulvic acid simulated water was employed to verify the coagulation efficiency. To obtain the optimal conditions for preparing the composite coagulant, the parameters affecting the coagulation performance such as Ti/Fe, P/Fe, OH/Fe, and oxidizer dosage were evaluated by single factor experiments and response surface methodology. The structure and morphology of PFTS were investigated by some conventional methods and those affecting coagulation–flocculation behaviors such as coagulant dosage, water sample initial pH, were also examined. Flocs properties of PFTS were investigated by Mastersizer 2000. The results indicated that PFTS presented a porous and a compacted gel network structure, in which some major phase structure and chemical bonds were discovered. The jar tests demonstrated the superior coagulation performance at coagulant dosage of 20–30 mg/L and the optimum pH range of 7–8. The optimum synthetic conditions were Ti/Fe, P/Fe, OH/Fe molar ratio and oxidant adding speed of 0.13, 0.25, 0.29, and 4 mL/min, respectively. Under the optimal condition, the residual turbidity, (Dissolved organic matter) DOC removal and residual iron of 0.82, 53 %, and 0.08 mg/L, respectively, could be acquired by PFTS. The flocs analysis results manifested that the dominant mechanism in flocs growth is absorption-bridging and sweeping coagulation, while charge neutralization mechanisms is the primary in the formation of compact flocs.
Co-reporter:Qingqing Guan;Jun Zhai;Bingzhi Liu;Yongjun Sun;Yili Wang;Zhinan Xu;Chun Zhao
Journal of Applied Polymer Science 2015 Volume 132( Issue 13) pp:
Publication Date(Web):
DOI:10.1002/app.41747
ABSTRACT
This study prepared TPDA, a high-intrinsic-viscosity cationic polyacrylamide, through ultraviolet (UV)-initiated template polymerization. Acrylamide (AM) and diallyldimethylammonium chloride (DMD) served as monomers, and poly sodium polyacrylate (PAAS) served as the template. The structure of TPDA was characterized by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and thermogravimetric analysis. The synthetic conditions of TPDA were studied and optimized by single-factor experiments. An optimized product was obtained at an intrinsic viscosity of 11.3 dL g−1 and a conversion rate of 97.2% with a total monomer concentration of 20%, DMD concentration of 30%, initiator concentration of 0.045%, pH of 8, EDTA concentration of 0.3%, and UV irradiation of 90 min. Results showed that TPDA was the copolymer of AM and DMD with a micro-block structure at the molecular chain. Given its high intrinsic viscosity and cationic block structure, TPDA performed better in kaolin flocculation than that prepared without template addition. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41747.
Co-reporter:Yongjun Sun;Mingzhuo Tan;Yili Wang;Xiaomin Tang;Li Feng;Xinyi Xiang
Journal of Applied Polymer Science 2014 Volume 131( Issue 7) pp:
Publication Date(Web):
DOI:10.1002/app.40062
Abstract
In this study, a new composite flocculant was prepared by premixing polymeric aluminum ferric sulfate (PAFS) with cationic polyacrylamide (CPAM) to treat textile dye wastewater. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were conducted to investigate the structure and morphology of the PAFS–CPAM. The effects of flocculant dosage, initial pH of textile dye wastewater, and settling time after flocculation on the removal of turbidity and chemical oxygen demand (COD) were examined. The flocculation efficiency of PAFS–CPAM for dye treatment was compared with PAFS, CPAM, PAFS/CPAM (PAFS followed by CPAM), and CPAM/PAFS (CPAM followed by PAFS). The synergy of PAFS and CPAM increased the (Fe–Al)b species of PAFS–CPAM. Treatment with PAFS–CPAM was more effective in removing turbidity and COD than PAFS, CPAM, PAFS/CPAM, and CPAM/PAFS. The turbidity and COD removal rates of textile wastewater were higher than 80 and 90% in the pH range of 5.5 to 8.5, respectively. Furthermore, PAFS–CPAM demonstrated excellent performance in reducing sludge volume after flocculation. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40062.
Co-reporter:Jiangya Ma;Mingzhuo Tan;Liwei Liu;Wei Chen;Qingqing Guan;Xiaokai Zheng
Journal of Applied Polymer Science 2013 Volume 129( Issue 4) pp:1984-1991
Publication Date(Web):
DOI:10.1002/app.38900
Abstract
In this study, a kind of anionic polyacrylamide (P(AM-AA-AMPS)) was synthesized using acrylamide (AM), acrylic acid (AA), and 2-acrylamido-2-methyl propane sulfonic acid (AMPS) under ultraviolet (UV) irradiation. The conditions of the polymerization reaction such as monomer mass ratio, solution pH value, EDTA concentration and urea concentration were investigated by using the single factor approach and an L16 (45) orthogonal array. The structure and morphologies of the copolymer were determined by nuclear magnetic resonance spectrometer (NMR), infrared spectrometer (IR) and scanning electron microscope (SEM). The results show P(AM-AA-AMPS) with the intrinsic viscosity of 1.5 × 103 mL g−1 was synthesized at optimal conditions: mass ratio, m(AM) : m(AA) : m(AMPS) of 70 : 10 : 10, pH value of 9.0, EDTA concentration of 0.10% and urea concentration of 0.20%. In addition, P(AM-AA-AMPS) had better flocculation efficiency than commercial PAM in sludge dewatering experiment; the minimum filter cake moisture content could be reduced to 65.1%. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Co-reporter:Tiroyaone Tshukudu;Xuebin Hua
Korean Journal of Chemical Engineering 2013 Volume 30( Issue 3) pp:649-657
Publication Date(Web):2013 March
DOI:10.1007/s11814-012-0169-y
Response surface method and experimental design were applied as alternatives to the conventional methods for optimization of the coagulation test. A central composite design was used to build models for predicting and optimizing the coagulation process. The model equations were derived using the least square method of the Minitab 16 software. In these equations, the removal efficiency of turbidity and COD were expressed as second-order functions of the coagulant dosage and coagulation pH. By applying RSM, the optimum condition using PFPD1 was coagulant dosage of 384 mg/L and coagulation pH of 7.75. The optimum condition using PFPD2 was coagulant dosage of 390 mg/L and coagulation pH of 7.48. Confirmation experiment demonstrated a good agreement between experimental values and model predicted. This demonstrates that RSM and CCD can be successfully applied for modeling and optimizing the coagulation process using PFPD1 and PFPD2.
Co-reporter:Xiaomin Tang, Huaili Zheng, Baoyu Gao, Chuanliang Zhao, Bingzhi Liu, Wei Chen, Jinsong Guo
Journal of Hazardous Materials (15 June 2017) Volume 332() pp:1-9
Publication Date(Web):15 June 2017
DOI:10.1016/j.jhazmat.2017.02.060
•bEOM as a bond between algae cells and PAC improved the algae treatment.•dEOM weakly reacted with PAC or inhibited coagulation.•Al13 and Al(OH)3(am) played an essential role in the dEOM and bEOM treatment.•It was recommended to treat the algae at its initial growth stage.Extracellular organic matter (EOM) is ubiquitous in the algae-polluted water and has a significant impact on the human health and drinking water treatment. We investigate the different characteristics of dissolved extracellular organic matter (dEOM) and bound extracellular organic matter (bEOM) recovered from the various growth period of Microcystis aeruginosa and the interactions of them and polyaluminum chloride (PACl). The roles of the different EOM in the algae-polluted water treatment are also discussed. The functional groups of aromatic, OH, NH, CN and NO in bEOM possessing the stronger interaction with hydroxyl aluminum compared with dEOM is responsible for bEOM and algae removal. Some low molecular weight (MW) organic components and protein-like substances in bEOM are most easily removed. And dEOM weakly reacts with PACl or inhibits coagulation, especially dEOM with the high MW organic components. The main coagulation mechanisms of bEOM are the generation of insoluble Al-bEOM through complexation, the bridge of AlO4Al12(OH)24(H2O)127+ (Al13), the adsorption of Al(OH)3(am) and the entrapment of flocs. The adsorption of Al13 and Al(OH)3(am) mainly contribute to dEOM removal. It is also recommended to treat the algae with dEOM and bEOM at the initial stage.Download high-res image (186KB)Download full-size image
