Polyelectrolyte complexes IV. Interpolyelectrolyte complexes between some polycations with N,N-dimethyl-2-hydroxypropyleneammonium chloride units and poly(sodium styrenesulfonate) in dilute aqueous solution

We report first on the interpolyelectrolyte complex formation (PEC) between one polycation of integral type having about 95 mol% of N,N-dimethyl-2-hydroxypropyleneammonium chloride units in the backbone (PCA₅) and poly(sodium styrenesulfonate) (NaPSS), in dependence on the polyion concentrations and the mixing order. The PEC formation was qualitatively followed by viscometry, conductometry and UV-spectroscopy. Quasi-soluble PECs could be formed in the polyion concentration range of 0.1-1.0 unit mM. A complex stoichiometry close to 1:1 was found by both the qualitative measurements on the formation of quasi-soluble PEC in dilute aqueous solutions (when PCA₅ concentration was lower than the overlap concentration, C<C^∗) and elemental analyses of the insoluble PEC formed at the high polycation concentration (50 unit mM, C?C^∗). The influence of the ionic strength on the PECs stability was followed by the subsequent addition of NaCl up to an ionic strength of 3.5 M on the reaction mixture, after the PECs formation with three polycations different by both the content of quaternary ammonium salt groups in the backbone and the degree of branching (PCA₅, PCA₂₀ and PCT₂₀). No dissociation of PECs into the original components was evidenced irrespective of the polycation structure and the mixing order.     

Settling characteristics of coal preparation plant fine tailings using anionic polymers

The objective of solid-liquid separation in thickeners in coal preparation plants is to obtain both a clear supernatant liquid with a low turbidity for reuse and a dense slurry. It is important for the smooth operation of the plant to produce good-quality recirculation water. In this study, settling characteristics of coal tailings (d₈₀=70 μm) taken from the thickener feed of Derekoy Coal Preparation Plant (Manisa, Turkey) were investigated with the use of anionic polymers. In the tests we determined the effects of the process parameters including polymer type, polymer dosage, temperature, suspension pH, and pulp density on the flocculation of the fine tailings of the coal preparation operation. Minefloc anionic polymer showed a better flocculation performance in comparison with other polymers. An optimum settling rate of 300 mm/min was reached at a dosage of 30 g/t-solids, a pulp density of 5%, pH 7.9, and temperature 25 °C using Minefloc polymer.     

Effect of the structure of cationic polysulfone on the flocculation of kaolinite

The behavior of polycations as flocculants for kaolinite was examined by means of turbidity measurement, with the use of the following four kinds of cationic polysulfones, with molecular weights ranging from 14,000 to 330,000; diallyldimethylammonium chloride SO₂ copolymer [P(DADMAmCl? SO₂)], diallyldiethylammonium chloride–SO₂ copolymer [P(DADEAmCl? SO₂)], diallylmethylamine hydrochloride–SO₂ copolymer [P(DAMA? HCl? SO₂)], diallylamine hydrochloride–SO₂ copolymer [P(DAAHCl? SO₂)]. The effect of the degree of polymerization on the flocculation was remarkable at low molecular weight range. The flocculation value, which is defined as the quantity of the polycation required to obtain 50% transparency at 660 mμ of the supernatant fluid of 2% kaolinite suspension, was inversely proportional to the degree of polymerization to the 0.734 power in the case of P(DADMAmCl? SO₂). This can be understood as the extension of Schulze-Hardy's law. The four different kinds of polysulfones having a similar molecular weight show almost the same capacity for flocculation in acidic or neutral solution. In alkaline solution, however, P(DAMAHCl? SO₂) and P(DAA? HCl? SO₂) are less effective and have higher flocculation values than P(DADMAmCl? SO₂) and P(DADEAmCl? SO₂), which are classified as polyquaternary ammonium chlorides. Moreover the difference increases with increasing pH. This may be attributable to the difference of the dissociability of the polycation. The degree of dissociation of P(DAMA? HCl? SO₂) or P(DAA? HCl? SO₂) decreases with increasing pH and more additive is required to neutralize negative charges on kaolinite. On the other hand, P(DADMAmCl? SO₂) and P(DADEAmCl? SO₂) are almost completely dissociated and are good flocculants over a wide range of pH.     

Synthesis and characterization of composite flocculant PAFS–CPAM for the treatment of textile dye wastewater

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.     

Coagulation performance of cationic polyelectrolyte/TiO2 nanocomposites prepared under LED irradiation

A series of acrylic-based cationic polyelectrolyte nanocomposites including water-soluble monomers acrylamide (AAm) and 2-acryloyloxyethyltrimethylammonium chloride (DAC) with different mole percent of DAC (30, 40, and 45%) in feed were produced using TiO₂ nanoparticles (0.018, 0.037, and 0.11 wt%) as photoinitiator in the aqueous solution of monomers and named as p(ADT)_1–9. The LED light at 365 nm was used for photocatalysis activation of TiO₂ nanoparticles. Structure and morphology of the synthetic polyelectrolyte were characterized by FT-IR, NMR, TGA, FESEM-EDX, and TEM. The other properties of synthetic polyelectrolyte such as molecular weight, viscosity, charge density, AAm/DAC molar ratio in copolymers, reactivity ratio values for the AAm and DAC monomers, and polymerization degree were measured. Furthermore, coagulation performance of these polyelectrolytes was investigated in soil suspension (1,000 ml, initial turbidity = 1,715 NTU). The prepared nanocomposites enhanced the coagulation of soil suspension up to 99.5% in low dosages. The best turbidity removal efficiencies (TRE) between 99.5–99.77% were achieved by p(ADT)₃ conatining 30% DAC and 0.11 wt% TiO₂. Decreasing the temperature from room temperature to 0°C led to an increase in TRE from 98 to 99.8%. Also, increasing the pH from 4 to 12 led to a decrease in TRE from 99.86 to 94%.     

Single and Combined Application of Ozonation and Coagulation/Flocculation for Humic Acid Removal

Humic acids are often found in surface and ground waters as a result of organic matter decay. In this study, water samples containing 50 mgL^?1 humic acid were treated by conventional application of coagulation/flocculation technique. The results showed 70% ±10 turbidity, ≥82% ±10 UV₂₅₄ absorbance and 85% ±10 total organic carbon removal under pH 5–9 and above 5 mgL^?1 Fe³⁺ coagulant doses. Application of post-ozonation significantly increased the UV₂₅₄ absorbance and turbidity removal under low dose Fe³⁺ application. On the other hand ozonation prior to coagulation/flocculation process altered the structure of HA and caused no significant improvement in removal efficiencies.     

Preparation and characterization of polymer-coated Fe3O4 magnetic flocculant

The ordinary flocculants rely on gravity settling for solid-liquid separation, it is difficult to meet the requirements of wastewater treatment in short flocculation settling time, few sludge production and low moisture content. A new type of flocculant is required to solve these difficulties. Magnetic materials are given more attention because of the magnetism in magnetic field. It is significant to prepare magnetic composite flocculant to realize solid-liquid separation with the combined effects of both gravity and external magnetic field. The gelatin-based magnetic flocculant consisted of poly (acrylamide-co-acryloyloxyethyl thimethylammonium chloride) grafted gelatin-coated Fe₃O₄ [magnetic poly (AM-co-DAC)-g-gelatin] was prepared in this article. A Box-Behnken design for determination of optimal plan with three-level and three-variable was designed. The best conditions of preparing magnetic poly (AM-co-DAC)-g-gelatin were determined. The structure of magnetic poly (AM-co-DAC)-g-gelatin was studied by infrared spectrum and its magnetic properties were characterized by magnetic hysteresis loop. The flocculation of magnetic poly (AM-co-DAC)-g-gelatin was compared with conventional flocculant. The flocculation experiment results showed that the magnetic poly (AM-co-DAC)-g-gelatin was effective for removal of turbidity and significantly reduced the settling time of flocs, compared to conventional flocculants.     

Synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones using ZrOCl2/mont K10 under microwave assisted solvent-free conditions

ZrOCl₂·8H₂O supported on montmorillonite K10 (ZrOCl₂/mont K10) catalyzed Biginelli reaction under solvent-free conditions is reported. The catalysts were characterized by XRD, FTIR, BET surface area analysis, and thermogravimetric analysis. The activity of montmorillonite K10, montmorillonite KSF, ZrOCl₂·8H₂O, SO₄ ^2?/ZrO₂, and ZrOCl₂/mont K10s was investigated by Biginelli reaction of benzaldehyde, ethylacetoacetate and urea. The reactions were carried out by addition of ZrOCl₂/mont K10 to a mixture of aldehyde, ethylacetoacetate and urea/thiourea with thorough stirring in the absence of solvent under conventional heating or microwave irradiation to prepare 3,4-dihydropyrimidin-2(1H)-one/thione derivatives at 80?°C in good yields.     

含沙高浊水最佳絮凝条件的确定

在含沙量为85kg／m^2的悬浊液中投加阳离子高分子聚合物,研究不同絮凝条件下絮体的自由沉速、结构密实程度、浑液面沉速与上清液余浊等的变化规律。利用“分维”作为定量控制参数研究含沙高浊水絮凝效果迭最佳时的絮凝条件（如搅拌速率、搅拌时间、高分子浓度等）,探讨了最佳絮凝条件下不同原始泥沙浓度对絮体分形结构的影响规律。实验得出85kg／m^2泥沙絮体结构密实性达最佳时的水力剪切强度Ct值存在两个临界值：快速絮凝阶段C1t1=2350,慢速絮凝阶段G2t2=12420。     

Dilute solution properties of cationic poly(dimethyl sulfate quaternized dimethylaminoethyl methacrylate)

The dilute solution properties of a cationic polyelectrolyte, poly(dimethyl sulfate quaternized dimethylaminoethyl methacrylate) [poly(DMAEM · C₂H₆SO₄)], are studied by measurements of intrinsic viscosity, degree of binding, and flocculation application. The intrinsic viscosity of this polyelectrolyte is related to the type and concentration of added salt. The intrinsic viscosity behavior for cationic polyelectrolyte resulting from the electrostatic repulsive force of the polymer chain is contrasted with polyampholyte. The polyelectrolyte in the presence of KCl has a lower degree of binding, indicating that the proton ion (H⁺) is relatively difficult to bind to the CH₃SO₄^? at the polymer end. The polymerization of DMAEM · C₂H₆SO₄ in 0.5M KCl aqueous solution proceeded more easily than that of DMAEM · C₂H₆SO₄ in pure water. The polymerization rate of DMAEM · C₂H₆SO₄ is found to pass through an extreme value as a function of pH. Optimum flocculation, corresponding to the complete removal of turbidity in the supernatant, is achieved. Beyond the optimum flocculation, high polymer dosages redisperse the bentonite suspensions.     

Organometallics in ethylene polymerization with a catalyst system TiCl4/Al(C2H5)2Cl/Mg(C6H5)2: 2. Polymerization process in pseudo-solution

A study has been made of ethylene polymerization in pseudo-solution with a catalyst system TiCl₄/Al(C₂H₅)₂Cl/Mg(C₆H₅)₂ in the presence of hydrogen as a regulator of polyethylene molecular weight. The polymerization process in pseudo-solution by adjustment of hydrogen makes it possible to produce polyethylene having a wide range of molecular weights. For this purpose melt indices between 0°–50°C/min are desirable and these values are not reached with a suspension type of ethylene polymerization with a catalyst system TiCl₄/Al(C₂H₅)₂Cl/Mg(C₆H₅)₂. The effect of the molar ratio cocatalyst/catalyst (Al/Ti and Mg/Ti) on the catalyst activity and on the polyethylene molecular weight was studied, together with the content of hydrogen as a regulator of the molecular weight. The catalyst productivity increased to some limiting molar ratio Mg/Ti and Al/Ti and further increase of organometallics in the catalyst system did not influence the polymer molecular weight. In the case of ethylene polymerization with this catalyst combination in the presence of hydrogen, some activation of the catalyst was observed. Two mechanisms, which may account for the activation effect of the hydrogen are discussed.     

Flocculation of reed pulp suspensions by quaternary chitosan‐nanoparticle SiO2 retention aid systems

The microparticle retention aid system has been a focus on the studies of paper‐making chemicals. N‐(2‐Hydroxy‐3‐trimethylammonio)‐propyl chitosan chlorider [quaternary chitosan (QCS)]—nanoparticle SiO₂ dual component system was investigated in this work. The adsorpton kinetic experiments indicated that there was a very fast (<1 min) polymer adsorption under good mixing conditions. Adsorption of QCS onto the fiber surface was followed by a rearrangement to reach an equilibrium conformation. At the same time, QCS chains, existing on the surface of fiber, could permeate into the porous of the fiber, resulting in the reducing of zeta potential of the cellulosic fiber. In addition, the flocculation would be increased with the increasing of SiO₂ when the fiber substrates surfaces was net positively charged by an adsorbed QCS layer. It was also found that ionic strength decreased significantly the flocculation efficiency in pure QCS system, whereas the turbidity of the reed pulp suspension increased slightly with the increasing of NaCl concentration in QCS‐SiO₂ systems. The effect of shear force on the flocculation was tested. It was shown shear led to floc breakage and decreased the flocculation. These phenomena were very obvious for one‐component system (QCS or C‐St), but the microparticle system (QCS‐SiO₂ or C‐St‐SiO₂) was shear resistance. Dynamic drainage experiment indicated that the turbidity of white water was decreased with the increasing of dosage of SiO₂ in experimental level. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis,Characterization, and Flocculation Performance of Water Soluble Pyridine Based Polyelectrolytes

A series of new 6-methyl-2-vinylpyridinium water soluble cationic poly-electrolytes were synthesized with Cl^?, Br^?, HSO₄^?, H₂PO₄^?, and NO₃^? as counter ions and were characterized by UV-visible, NMR, FTIR, and mass spectral studies. The intrinsic viscosity, electrical conductivity, and charge density of the polyelectrolytes were also determined. The effect of counter ion on flocculating ability of polyelectrolytes was investigated with tannery effluent at different concentrations (10–200 ppm). The total suspended solids (SS), COD and BOD, were determined for supernatant solutions to ascertain the extent of flocculation. The flocculating ability was found to be directly proportional to the concentration of the polyelectrolytes.     

Bilge Water Treatment in an Upflow Electrochemical Reactor using Pt Anode

Bilge water treatment was studied in an upflow electrochemical reactor (UECR) in order to design a compact onboard wastewater treatment system. The influence of retention time on the removal efficiencies of chemical oxygen demand (COD) and turbidity were analyzed, and optimized using response surface methodology (RSM) for maximizing the removal efficiencies. The best operating performance was obtained at 390 min retention time and 480 min reaction time for cost effective analysis with the composition of 100% bilge water (COD_o = 3080 mg/L) and 50/50% seawater/fresh water, 12.8 mA/cm² current density, and 32°C reaction temperature. Under response surface optimized conditions, the responses were estimated as; 90% COD removal, 97% turbidity removal, outlet pH value of 8.1, mass transfer coefficient of 0.494 × 10^?5 m/s, and mean energy consumption of 44.8 kWh/kg COD removed.     

Facile fabrication approach for a novel multifunctional superamphiphobic coating based on chemically grafted montmorillonite/Al<Subscript>2</Subscript>O<Subscript>3</Subscript>-polydimethylsiloxane binary nanocomposite

In this paper, a novel multifunctional superamphiphobic coating for anticorrosion was successfully prepared on aluminum substrate via a simple spraying technique. Al₂O₃ nanoparticles were chemically grafted onto montmorillonite (MMT) nanosheets via coupling effect of NH₂-C₃H₆-Si(OC₂H₅)₃ (KH-550) and then modified by low surface energy material polydimethylsiloxane (PDMS). The ethylene tetrafluoroethylene (ETFE) composite coating with 25 wt% MMT/Al₂O₃-PDMS binary nanocomposite exhibited well-designed nano/μ structures and possessed superamphiphobicity with high contact angles towards water (164°), glycerol (158°) and ethylene glycol (155°). This coating demonstrated outstanding self-cleaning ability and strong adhesive ability (Grade 1 according to the GB/T 9286). The superhydrophobicity could be maintained after 8000 times abrasion or annealing treatment for 2 h under 350 °C. The coating still retained high water-repellence after immersion in 1 mol/L HCl (146°), 1 mol/L NaOH (144°) and 3.5 wt% NaCl (151°) solutions for 30 d. It should be noted that this superamphiphobic coating revealed excellent long-term corrosion protection with extremely low corrosion rate (4.3 × 10^?3 μm/year) and high protection performance (99.999%) after 30 d immersion in 3.5 wt% NaCl solutions based on electrochemical corrosion measurements. It is believed that such integrated functional coating could pave new way for self-cleaning and anticorrosion applications under corrosive/abrasive environment.     

Influence of different concentrations of Al2(SO4)3 and anionic polyelectrolytes on tannery wastewater flocculation

Tanning of hides and skins to convert them into leather can have a considerable environmental impact. Wastewatertreatment technology can successfully purify leather wastewater. The first part of this research investigated the influence of Al₂(SO₄)₃ concentration on the velocity of tannery wastewater settling. The wastewater sample was taken from two of the most polluted wastewater flows after liming and after chrome tanning. These wastewater flows were mixed together in a ratio of 1:1. The second part was carried out with the samples of wastewater mixed together with different concentrations of A1₂(SO₄)₃. The behaviour of settling was investigated after an addition of different concentrations of anionic polyelectrolytes in these samples. The pH, suspended solids mass, volume of sediment, γ(Na₂S), γ(Cr₂O₃), chemical oxygen demand, along with turbidity in the supernatant were determined in the obtained sludge. The results demonstrate the influence of A1₂(SO₄)₃ and anionic polyelectrolyte concentrations on the parameters studied and the improvement of environmental properties.     

Cellulose nanofibers prepared from TEMPO‐oxidation of kraft pulp and its flocculation effect on kaolin clay

Cellulose nanofibers were prepared using TEMPO/NaBr/NaClO oxidation of kraft pulp and successive ultrasonic treatment, and the properties were characterized by conductimetric titration, X‐ray diffraction, and atomic force microscopy. The resulting product was then applied as an anionic microparticle to constitute a microparticulate system with cationic polyacrylamide (CPAM), to induce the flocculation of the kaolin clay suspension. The flocculation effect was evaluated by determining the relative turbidity of clay suspension. The results showed that the obtained cellulose nanofibers had cellulose I structure with higher crystallinity than that of the kraft pulp, and their cross‐sectional dimension was in the range of 3–5 nm. They had more negative zeta potential at neutral and alkaline conditions. It was found that the microparticulate system showed high flocculation effect on kaolin clay at a very low level of nanofiber addition, and a high shear level after CPAM addition was helpful for the flocculation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40450.     

Effects of O3, O3/H2O2 and Coagulation on Natural Organic Matter and Arsenic Removal from Typical Northern Serbia Source Water

The objectives of this study were to investigate the effects of ozone and the O₃/H₂O₂ process on FeCl₃ coagulation efficiency for the removal of the high content of natural organic matter (NOM) and arsenic (As) from groundwater (DOC = 9.27 ± 0.92 mg/L; 51.7 ± 16.4 µg As/L). Arsenic and NOM removal mechanisms during coagulation/flocculation are well investigated. However, data concerning arsenic removal in the presence of NOM, which is the subject of this article, are still insufficient. Laboratory and pilot plant test results have shown that the competition of NOM and As for adsorption sites on the coagulant surface have great influence on coagulation/flocculation efficiency for their removal. With both oxidation pre-treatments, arsenic content after the coagulation process was less than 2.0 µg/L in treated water. Application of ozone has a lower influence on coagulation efficacy in terms of DOC reduction, compared to the O₃/H₂O₂ process with the same ozone dose.     

Influence of technological parameters on the epoxidation of 1‐butene‐3‐ol over titanium silicalite TS‐2 catalyst

BACKGROUND: The influence of technological parameters on the epoxidation of 1‐butene‐3‐ol (1B3O) over titanium silicalite TS‐2 catalyst has been investigated. Epoxidations were carried out using 30%(w/w) hydrogen peroxide at atmospheric pressure. The major product from the epoxidation of B3O was 1,2‐epoxybutane‐3‐ol, with many potential applications. RESULTS: The influence of temperature (20–60 °C), 1B3O/H₂O₂ molar ratio (1:1–5:1), methanol concentration (5–90%(w/w)), TS‐2 catalyst concentration (0.1–6.0%(w/w)) and reaction time (0.5–5.0 h) have been studied. CONCLUSION: The epoxidation process is most effective if conducted at a temperature of 20 °C, 1B3O/H₂O₂ molar ratio 1:1, methanol concentration (used as the solvent) 80%(w/w), catalyst concentration 5%(w/w) and reaction time 5 h. Copyright © 2009 Society of Chemical Industry     

Nanostructure and viscoelasticity of layered silicate nanocomposite–electrolyte supports

There is the need for novel polyelectrolytes with enhanced thermal and mechanical properties. In this report, we have reinforced a polyelectrolyte based on poly(dimethylaminoethylmethacrylate) (PDMAEM) using nanoclay montmorillonite (MMT), and have studied the thermal and viscoelastic properties. The protonated polymer (PDMAEMH) was solution mixed with functionalized MMT. Recognizing that the sort of surfactant may have a profound influence on the physical properties of the polymer matrix, neat MMT, and MMT treated with different surfactants (sulfobetaine and ammonia) were used, and the concentration of the nanofiller was varied from 1 to 5%w/w. Strikingly, while PDMAEM exhibited a glass transition temperature T_g of 32°C, the protonated PDMAEMH showed T_g = 155°C. Master curves obtained by applying the time‐temperature superposition principle showed that PDMAEM behaved predominantly elastic (G″ < G′) suggesting an entangled polymer melt. However, PDMAEMH exhibited much longer relaxation times, a shift of ca. seven decades in frequency, suggesting that ionic interactions significantly hampered the molecular dynamics. X‐ray scattering demonstrated that lower concentration and sulfobetaine surfactant favored exfoliation whereas ammonia and untreated MMT favored intercalation of the nanoplates. Furthermore, an enhancement in dynamic storage shear modulus was observed for the nanocomposites exhibiting intercalated morphologies relative to those displaying an exfoliated morphology. It is then suggested that the molecular dynamics is further slowed down due to confinement of the macromolecules between the nanoplates. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011