Template Copolymerization Research Articles

Evaluation an anionic polyacrylamide flocculant with microblock structure in the hematite wastewater treatment: Characterization and flocculation performance

In this study, a template polymer with anionic microblock structure was successfully synthesized through ultrasonic initiated template copolymerization (USTP) by using sodium allylsulfonate (SAS) and acrylamide (AM) as monomers, poly diallyl dimethyl ammonium chloride (polyDADMAC) as template, and 2,2′-azobis [2-(2-imidazolin-2-yl) propane] dihydrochloride (VA-044) as initiator. The anionic polyacrylamide (APAM-T) flocculant was characterized by Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance spectroscopy (1H NMR), and scanning electron microscopy (SEM). Furthermore, the X-ray photoelectron spectroscopy (XPS) was conducted to measure the elemental composition. The results of XPS and 1H NMR spectroscopy analysis indicated the existence of anionic microblock structure in APAM-T. Besides, the copolymerization was revealed to follow the self-assembly mechanism by analyzing the association constant (KM). The flocculation performance was evaluated by turbidity and zeta potential in the flocculation tests. The results indicated that the APAM-T with microblock structure enhanced the charge neutralization and bridging adsorption capacity, thus improving the flocculation performance. In the floc particle size distribution and fragmentation and reflocculation experiments, the floc corresponding to APAM-T had the strongest regeneration ability after fragmentation, which further confirmed the criticality of the microblock structure in enhancing the flocculation performance. Compared with existing studies, this study not only demonstrated a novel synthesis method, but also found that the microblock structure could significantly improve its treatment efficiency and effectiveness, providing a new theoretical basis and practical application path for wastewater treatment technology.

Preparation of amphiphilic cationic polyacrylamide (CPAM) with cationic microblock structure to enhance printing and dyeing sludge dewatering and condition performance.

Flocculation is an important pretreatment technology for sludge dewatering, and the flocculant's performance is the key factor to determine the flocculation effect. Cationic polyacrylamide (CPAM) is commonly used in dewatering and conditioning of printing and dyeing sludge (PD sludge), and the research of high-efficiency flocculant is a hot spot in the field of PD sludge dewatering. Hydrophobic butylacrylate (BA) and (2-(Methacryloyloxy)ethyl) trimethylammonium chloride (DMC) were introduced into the copolymer, and amphiphilic (hydrophilic/lipophilic) CPAM, namely TP-ADB, with microblock structure was synthesized by ultrasonic initiated template copolymerization in this study. The functional group composition of TP-ADB was determined by FTIR and 1H NMR. Thermogravimetric analysis (TGA) showed that TP-ADB had good thermal stability. The amphiphilic rheological properties of the copolymer were measured according to the apparent viscosity. In addition, 1H NMR and TGA results confirmed the existence of microblock structure in the copolymer chain. The polymerization mechanism was discussed by association coefficient (KM) measurement. The results showed that the template copolymerization initiated by ultrasonic followed the law of free radical copolymerization. The pre-adsorption of DMC with sodium polyacrylate template (NaPAA) before the reaction confirmed that the template polymerization accorded with ZIP I mechanism. The cationic microblock structure and hydrophobic association of TP-ADB promoted the dewatering performance of PD sludge (FCMC = 72.9%, turbidity removal rate = 98.9%, SRF = 4.2 × 1012m·kg-1). Hydrophobic association enhanced the bridging, sweeping, and net catching effect, and promoted the growth of floc size and fractal dimension. Cationic microblock structure can produce compact floc with higher mechanical strength by enhancing electrical neutralization and electrical patching. As a skeleton, the compressibility of filter cake was reduced and the permeability was enhanced, and the PD sludge dewatering effect was significantly improved.

A microblock structure type of anionic flocculant for hematite wastewater treatment: template copolymerization mechanism and enhanced flocculation effect.

In this study, a novel anionic template polymer (TPAS) with microblock structure was prepared by ultraviolet light (UV)-assisted template copolymerization (UV-TP). Acrylamide (AM) and sodium styrene sulfonate (SSS) were selected as monomers and polypropylene ammonium chloride (PAAC) was chosen as the template. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), nuclear magnetic resonance hydrogen spectroscopy (1H NMR), and thermogravimetry/differential scanning calorimetry (TG/DSC) were used to characterize the polymer chemical structure. The results showed that the attractive anionic microblock structure was formed in TPAS. Besides, the association constant (KM) and template reaction kinetics analysis results indicated that the polymerization reaction followed I (ZIP) template copolymerization mechanism. It proved the microblock structure formation again. The anionic microblock structure in TPAM could greatly improve the ability of charge neutralization, electrical patching, and bridging. After the hematite wastewater was conditioned by TPAS with this novel anionic microblock structure, the generated hematite flocs had larger particle size and denser structure. It was favorable for the reduction of turbidity, and the turbidity removal rate could reach 97.8%. TPAS showed excellent flocculation performance for hematite wastewater and had a broad market application prospect.

Enhanced municipal sludge dewaterability using an amphiphilic microblocked cationic polyacrylamide synthesized through ultrasonic-initiation: Copolymerization and flocculation mechanisms

Flocculation is an important pretreatment technique for sludge dewatering, the performance of employed flocculants is the key factor determine the flocculation efficiency. Herein, an amphiphilic cationic polyacrylamide (CPAM) with microblock structure was synthesized through template copolymerization initiated by ultrasonic. The chemical components and cationic microblock structure of copolymers were confirmed through comparative characterization by Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (1H NMR) spectrum. The copolymerization mechanism was investigated through kinetics study and association coefficient (KM) determination. The results indicated that the reaction followed free radical copolymerization and terminated mainly through bimolecular termination. The pre-adsorption between acryloyloxyethyltrimethylammonium chloride (DAC) and sodium polyacrylate (NaPAA) before reaction confirmed the template polymerization met the type I (ZIP) mechanism. Cationic microblocks and hydrophobic association together contributed to the optimal dewaterability (FCMC=67.2 %, SRF=3.84×1012 m·kg−1) using TP(AM-DAC-LA). Hydrophobic association enhanced bridging and sweeping effect to promote the floc size growth. Cationic microblocks produced compacter flocs with stronger mechanical strength through enhanced charge neutralization and patching effects, which acted as skeletons to make filter cakes less compressible and more permeable in mechanical dewatering. This work developed a highly effective flocculant for sludge dewatering, the synthesis and working mechanism of which were also given.

Hydrophobic modification of cationic microblocked polyacrylamide and its enhanced flocculation performance for oily wastewater treatment

In this study, a novel amphiphilic flocculant TP-ADL was synthesized using acrylamide, methacryloxyethyltrimethyl ammonium chloride and lauryl acrylate as monomers through UV-light-initiating template copolymerization technology. Copolymerization conditions were optimized towards higher intrinsic viscosity and conversion rate. The Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy (NMR) analysis confirms the functional groups composition in TP-ADL, and the thermogravimetric (TGA) analysis indicates its good thermal stability. Furthermore, the detailed 1H NMR and TGA analysis confirms the microblock structure in polymer chain. The amphiphilic rheological characteristics of copolymer were detected according to apparent viscosity. TP-ADL displayed superior flocculation efficiency towards oily wastewater in terms of oil and turbidity removal rate, and zeta potential. The median floc size (d50) and fractal dimension (Df) results indicate a large and compact floc structure. The synergistic effect between cationic microblock structure and inter-molecular hydrophobic association is the main reason for the better treatment efficiency.

Review of the Template Copolymerization of Cationic Polyacrylamide

Review of the Template Copolymerization of Cationic Polyacrylamide

Using ultrasonic (US)-initiated template copolymerization for preparation of an enhanced cationic polyacrylamide (CPAM) and its application in sludge dewatering

In this study, the ultrasonic (US)-initiated template copolymerization was employed to synthesize a novel cationic polyacrylamide (CPAM) characterized by a microblock structure using dimethyldiallylammonium chloride (DMDAAC) and acrylamide (AM) as monomers, and sodium polyacrylate (NaPAA) as template. The polymers structure property was analyzed by Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance spectroscopy (1H NMR) and thermogravimetric analysis (TGA). The results showed that a novel cationic microblock structure was successfully synthesized in the template copolymer of DMDAAC and AM (TPADM). Meanwhile, the analysis result of association constant (MK) provided powerful support for a I Zip-up (ZIP) template polymerization mechanism and the formation of the microblock structure. The factors affecting the polymerization were investigated, including ultrasonic power, ultrasonic time, monomer concentration, initiator concentration, mAM:mDMDAAC and nNaPAA:nDMDAAC. The sludge dewatering performance of the polymers was evaluated in terms of specific resistance to filtration (SRF), filter cake moisture content (FCMC), floc size (d50) and fractal dimension (Df). Flocculation mechanism was also analyzed and discussed. The sludge dewatering results revealed that the polymer with the novel microblock structure showed a more excellent flocculation performance than those with randomly distributed cationic units. A desirable flocculation performance with a SRF of 4.5 × 1012 m kg−1, FCMC of 73.1%, d50 of 439.156 µm and Df of 1.490 were obtained at pH of 7.0, dosage of 40 mg L−1 and the molecular weight of 5.0 × 106 Da. The cationic microblock extremely enhanced the polymer charge neutralization and bridging ability, thus obtaining the excellent sludge dewatering performance.

Acidic Derivatives of Melamine as Template in Copolymerization of Aniline and Metanilic Acid

ABSTRACTIn this paper, new polymer composites were synthesized by template copolymerization of aniline and metanilic acid in the presence of prepared melamine triacetic acid and poly(melamine-co-citric acid) as polyacids and dopants. The properties of the poly(aniline-co-metanilic acid) composites were studied by Fourier transform infrared, X-ray diffraction, scanning electron microscope, CV, and differential scanning calorimeter analysis. The four-point probe technique was used for evaluating the electrical conductivity of the composites. The scanning electron micrographs disclosed that the products had the morphology with agglomerated distorted spherical shapes with the average size of 40–50 nm. Also, the solubility of the composites had been improved notably in organic solvents.

Effect of the Cationic Block Structure on the Characteristics of Sludge Flocs Formed by Charge Neutralization and Patching.

In this study, a template copolymer (TPAA) of (3-Acrylamidopropyl) trimethylammonium chloride (AATPAC) and acrylamide (AM) was successfully synthesized though ultrasonic-initiated template copolymerization (UTP), using sodium polyacrylate (PAAS) as a template. TPAA was characterized by an evident cationic microblock structure which was observed through the analyses of the reactivity ratio, Fourier transform infrared spectroscopy (FTIR), 1H (13C) nuclear magnetic resonance spectroscopy (1H (13C) NMR), and thermogravimetry/differential scanning calorimetry (TG/DSC). The introduction of the template could improve the monomer (AATPAC) reactivity ratio and increase the length and amount of AATPAC segments. This novel cationic microblock structure extremely enhanced the ability of charge neutralization, patching, and bridging, thus improving the activated sludge flocculation performance. The experiments of floc formation, breakage, and regrowth revealed that the cationic microblock structure in the copolymer resulted in large and compact flocs, and these flocs had a rapid regrowth when broken. Finally, the larger and more compact flocs contributed to the formation of more channels and voids, and therefore the specific resistance to filtration (SRF) reached a minimum.

Optimized preparation of micro-block CPAM by response surface methodology and evaluation of dewatering performance

Micro-block cationic polyacrylamide (P(AM-MAPTAC)) was synthesized through UV-initiated template copolymerization and characterized by FTIR, 1H NMR, SEM and TG/DSC analyses.

Enhancement of textile-dyeing sludge dewaterability using a novel cationic polyacrylamide: role of cationic block structures

A novel cationic polyacrylamide (CPAM) with a microblock structure was synthesized through ultrasonic-initiated template copolymerization (UTP) using allyltrimethylammonium chloride (TM) and acrylamide (AM) as monomers, and sodium polyacrylate (NaPAA) as a template.

UV-initiated template copolymerization of AM and MAPTAC: Microblock structure, copolymerization mechanism, and flocculation 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.

One-dimensional copolymer nanostructures loaded with silver nanoparticles fabricated via metallogel template copolymerization and their pH dependent photocatalytic degradation of methylene blue

Abstracts pH responsive poly( N , N ′-methylenebisacrylamide-co-acrylic acid) (P(MBA–AAc)) one-dimensional (1D) nanostructures and silver nanoparticles (Ag NPs) loaded P(MBA–AAc) nanowires have been successfully synthesized via silver metallogel template copolymerization, and subsequently template removal or silver ions reduction, respectively. The Ag NPs with a diameter of 4–10 nm were exclusively dispersed throughout the P(MBA–AAc) nanowires. The size and distribution of the formed Ag NPs could be controlled by reduction time. The pH-responsive behaviors of P(MBA–AAc) 1D nanostructures at various molar ratios of MBA/AAc were investigated. Their adsorption and release of methylene blue (MB), as well as the photodegradation of MB catalyzed by Ag NPs loaded P(MBA–AAc) nanowires were all significantly dependent on the pH values of MB solution. The Ag NPs loaded P(MBA–AAc) nanowires could effectively catalyze the photodegradation of MB and the photodegradation rate of MB at pH 7 was almost four times than that at pH 2.2.

Metallogel template fabrication of pH-responsive copolymer nanowires loaded with silver nanoparticles and their photocatalytic degradation of methylene blue.

Poly(N,N'-methylenebisacrylamide-4-vinylpyridine) (P(MBA-4VP)) nanowires loaded with silver nanoparticles (Ag NPs) have been fabricated by silver metallogel template copolymerization, and subsequently, silver ions are reduced instead of the template being removed. Ag NPs with a diameter of 5-15 nm were dispersed throughout the core of P(MBA-4VP) nanowires. The size and distribution of the formed Ag NPs could be finely controlled by reduction time. The pH sensitivity of P(MBA-4VP) nanowires offers the possibility of Ag NP release from the nanowires under acidic conditions. The photocatalytic performance of the P(MBA-4VP) nanowires loaded with Ag NPs was evaluated for the degradation of methylene blue (MB) under UV light irradiation. Their rate of degradation is dependent on the content and size of the Ag NPs, as well as the pH values of the MB solution. Moreover, the P(MBA-4VP) nanowires loaded with Ag NPs exhibited high photostability, and the photocatalytic efficiency reduced by only 1.81% after being used three times.

Gamma radiation induced preparation of organic-inorganic composite material for sorption of cesium and zinc

A novel composite material, poly(acrylamide-acrylic acid-acrylonitrile)-N,N′-methylenediacrylamide/silicon oxide-zirconium oxide [P(AM-AA-AN)-DAM/SiO2-ZrO2], was prepared by γ-radiationinduced template copolymerization of acrylic acid (AA) with acrylonitrile (AN) on polyacrylamide P(AM) as a template polymer in presence of N,N′-methylenediacrylamide (DAM) as cross-linker in aqueous solution with water-insoluble mixed oxide of silicon and zirconium. The composite material was characterized by Fourier transform IR spectroscopy and by thermal analysis (synchronized TGA-DTA). The sorption of 134Cs and 65Zn(II) onto the prepared composite material was investigated using batch equilibrium technique with variation of pH, adsorbent weight, initial sorbate concentration, contact time, and temperature. The sorption equilibrium data were fitted with the Langmuir and Freundlich isotherm models. The isotherm is successfully fitted by the Langmuir equation over the entire concentration range studied. Lagergren pseudo-first- and pseudo-secondorder kinetic models were tested to describe the reaction mechanism. The experimental data are fitted well the pseudo-second-order model. The thermodynamic functions (free energy ΔG0, enthalpy ΔH0, entropy ΔS0) of the sorption were calculated. These quantities show that the sorption of 134Cs and 65Zn onto the composite material is spontaneous and endothermic.

Stimuli-responsive one-dimensional copolymer nanostructures fabricated by metallogel template polymerization and their adsorption of aspirin.

pH responsive poly(N,N'-methylenebisacrylamide-co-4-vinylpyridine) (P(MBA-4VP)) one dimensional (1D) nanostructures have been prepared by metallogel template copolymerization, which was carried out in an Ag(i)-coordinated organogel with benzoyl peroxide (BPO) as the initiator. The product has been characterized using infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. The experimental results reveal that the gel fiber is a crucial template for polymerization. Due to the degradation of the template in copolymerization, nanofibers of metallogel were transcribed to copolymer nanowires. The introduction of co-monomer 4-vinylpyridine (4VP) imparts to the 1D copolymer nanostructures pH sensitivity and the possible use as an adsorption material of aspirin. Adsorbed 1D copolymer nanostructures could be regenerated using proton solvent, acid medium and salt solution. In addition, silver nanoparticle loaded copolymer nanowires have been produced from the reduction of silver ions instead of template removal, where silver ions act both as the template and as the nanoparticle growth substrate.

Stable and pH-responsive core–shell nanoparticles based on HEC and PMAA networks via template copolymerization

Taking advantage of the specific hydrogen bonding interactions, stable and pH-responsive core–shell nanoparticles based on hydroxyethyl cellulose (HEC) and polymethacrylic acid (PMAA) networks, with a 〈D h 〉 size ranging from 190 to 250 nm, can be efficiently prepared via facile one-step co-polymerization of methacrylic acid (MAA) and N,N′-methylenebisacrylamide (MBA) on HEC template in water. Using dynamic light scattering, electrophoretic light scattering, fluorescence spectrometry, thermo-gravimetric analysis, TEM, and AFM observations, the influence of crosslinker MBA as well as the reaction parameters were studied. The results show that after the introduction of crosslinker MBA, the nanoparticles became less compact; their size exhibited a smaller pH sensitivity, and their stability against pH value was improved greatly. Furthermore, the size, structure, and pH response of the nanoparticles can be adjusted via varying the reaction parameters: nanoparticles of smaller size, more compact structure, and higher swelling capacity were produced as pH value of the reaction medium increased or the HEC/MAA ratio decreased; while nanoparticles of smaller size, less compact structure and smaller swelling capacity were produced as the total feeding concentration increased.

Fabrication and responsive behaviour of Quantum Dot/PNIPAM micropatterns obtained by template copolymerization in water

A facile method for the fabrication of Quantum Dot/poly(N-isopropylacrylamide) (QD/PNIPAM) micropatterns on glass is presented. Water-soluble QDs functionalized with polymerizable methacrylic groups effectively copolymerize with N-isopropylacrylamide monomer resulting in stable hybrid organic–inorganic networks. The patterns display temperature and pH responsive luminescence behaviour.

Radiation Synthesis of Poly(Acrylamide-Acrylic Acid-Dimethylaminoethyl Methacrylate) Resin and Its Use for Binding of Some Anionic Dyes

Poly(acrylamide-acrylic acid-dimethylaminoethyl methacrylate) P(AAm-AA-DMAEMA) resin was prepared by the template copolymerization. PAAm was used as a template for the copolymerization of DMAEMA and AA in aqueous solution using gamma rays. The adsorption of indigo carmine and eriochrome black-T anionic dyes from aqueous media on P(AAm-AA-DMAEMA) has been investigated. The adsorption behavior of this resin has been studied under different adsorption conditions: dye concentrations (50–500 mg l−1), contact times, temperature (30–55°C), and pH values (2–7). The amount of dye adsorbed increased with increasing resin content, but it had a little change with temperature and decreased slightly with increasing pH. Adsorption data of the samples were modeled by the pseudo-first-order and pseudo-second-order kinetic equations in order to investigate dye adsorption mechanism. It was found that the adsorption kinetics of the resin followed a pseudo-second-order model with rate constant (k 2) of 2.5 × 10−3 and 1.8 × 10−2 g (mg−1 min−1) for indigo carmine and eriochrome black-T, respectively. Equilibrium isotherms were analyzed using the Langmuir and Freundlich isotherms. It was seen that the Freundlich model fits the adsorption data better than the Langmuir model.

Development of chromatographic separation of some biological materials using poly(acrylamide-acrylic acid-dimethylaminoethyl methacrylate) resin

The aim of the present study is to develop of chromatographic separation of some biological materials using poly(acrylamide-acrylic acid-dimethylaminoethyl methacrylate) resin P(AAm-AA-DMAEMA). The copolymer was prepared by a template copolymerization of DMAEMA and AA in aqueous solution on polyacrylamide (PAAm) as a template polymer and N,N-methylenebisacrylamide (NMBA) as a crosslinker using gamma rays as initiator. Some biological materials such as alpha-fetoprotein (AFP), bovine serum albumin (BSA) and tri-iodothyronine (T3) were labeled using 125I and the purifications of all tracers were carried out using prepared resin compared with Sephadex. Factors affecting were studied to reach the most efficiency purification including pH buffer, variable elution volumes, flow rate and temperature. The radiochemical purity percent was determined using paper electrophoresis and immunoreactivity of tracer was checked. The efficiency of purification that obtained using the prepared resin is nearly equivalent to that of Sephadex.