Use Of Polyelectrolyte Research Articles

Impact of Conditioning Substances and Filtration Pressure on Dewatering Efficiency of Sewage Sludge

Sludge dewatering is a key element in sludge’s processing and management. Solid-phase separation, sludge volume reduction and the separation of a high-quality supernatant are the main tasks of the dewatering devices. The effectiveness of this task, in turn, results from the selection of the dewatering method and conditioning of the sludge before dewatering. The aim of the research was to determine the influence of conditioning substances (polyelectrolyte, fly ash and zeolite) on the efficiency of dewatering at variable filtration pressure. The use of polyelectrolyte in sludge conditioning was a solution that increased the efficiency of the filtration process. On the contrary, the use of structure-forming substances (fly ash and zeolite) slows the process but reduces the hydration of the filter cake. The same trends were obtained in dual conditioning combining dosing of polyelectrolyte and ash or zeolite. It was also shown that the dewatering efficiency of conditioned sludge with these two different substances (ash and zeolite) was the same. The use of zeolite in independent or dual conditioning was important for the quality of the supernatant.

Synthesis of polystyrene-based fluorescent quantum dots nanolabel and its performance in H5N1 virus and SARS-CoV-2 antibody sensing

Quantum dots (QDs) based fluorescent nanobeads are considered as promising materials for next generation point-of-care diagnosis systems. In this study, we carried out, for the first time, the synthesis of QDs nanobeads using polystyrene (PS) nanobead as the template. QDs loading on PS nanobead surface in this method can be readily achieved by the use of polyelectrolyte, avoiding the time-consuming and uncontrollable silane reagents-involved functionalization procedure that conventional synthesis of silica-based QDs nanobeads often suffer from. Notably, the application of QDs nanobeads in suspension microarray for H5N1 virus detection leads to a sensitivity lower than 25 PFU/mL. In addition, QDs nanobead was also incorporated into lateral flow assay for SARS-CoV-2 antibody detection, leading to more than one order of magnitude detection sensitivity as compared to that of commercial one based on colloid gold.

Arıtma çamurlarının su verme özelliklerinin iyileştirilmesinde biyokütle ve kömür külü ilavesinin etkilerinin incelenmesi

Diminishing the amount of water in sewage sludges is the most determinant factor in terms of increasing the options of removing and being reduced the number of sludges to remove. In the current situation, the most preferred methods are the mechanic methods for sludge dewatering. But, the quenching features of the sludge must be improved and the conditioning procedures need to be actualized by adding polyelectrolyte into the sludge to enhance the productivity of the mechanical methods. As an alternative to the use of polyelectrolyte in sludge conditioning procedure, the effects of the use of biomass and coal ash on the quenching features are analyzed in this research. For this purpose, the biomass and the coal ash were mixed with the sewage sludges in different ratios. The 1/1000 cationic polyelectrolyte solution was used as the control application. According to the results obtained from the study, as the ash content in the mixtures increases, the specific resistance to filtration (SRF) and the filter cake moisture content (FCM), which are the most important indicators of water quenching properties, have been significantly reduced. The closest results to the polyelectrolyte application (SRF 2,8.1011 m.kg-1, FCM: % 58,96) used as the control were obtained from the BC6 application (SRF: 29.1011 m.kg-1, FCM: % 65,92) where the highest ratio of biomass ash used. Moreover, the results of the implementations of biomass and coal ash are determined as statistically similar (R2=0,99). In the content of biomass and coal ash heavy metals, it is seen that the ratios of heavy metal of biomass ash are lower for all values other than Zn. It is thought according to these results that the biomass and coal ash can be used to improve the dewatering features of domestic waste water treatment sludges. However, considering the heavy metal level of the sludge, it can be said that the best alternative is the use of biomass ash for increasing the disposal options after dewatering.

Synthesis of carbon nanotube/anatase titania composites by a combination of sol–gel and self-assembly at low temperature

A simple method is described for the synthesis of carbon nanotube/anatase titania composites by a combination of a sol–gel method with a self-assembly technique at 65 °C. This method makes use of polyelectrolyte for wrapping multi-walled carbon nanotube (MWCNT) and providing them with adsorption sites for electrostatically driven TiO 2 nanoparticle deposition. The composites were characterized using X-ray diffraction, transmission electron microscopy, Fourier transform infrared and X-ray photoelectron spectroscopy, and photoluminescence for analyzing their crystal phase, microstructure, particle size, and other physicochemical properties. The results showed that MWCNT were covered with an anatase TiO 2 thin layer or surrounded by an anatase TiO 2 thick coating, which is constructed of TiO 2 particles about 6 nm in size. The composites were rich in surface hydroxyl groups. The excited e − in conduction band of TiO 2 may migrate to MWCNT. Concerning the potential applicability, MWCNT/TiO 2 composites showed excellent photocatalytic activity toward the photodegradation of methyl orange.

Layer-by-Layer Deposition of Polyelectrolyte−Polyelectrolyte Complexes for Multilayer Film Fabrication

Positively charged poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) complexes (noted as PAH-PAA) with a molar excess of PAH were layer-by-layer (LbL) assembled with polyanion poly(sodium 4-styrenesulfonate) (PSS) to produce multilayer films. The film structure and deposition behavior of the PAH-PAA/PSS films were influenced by the structure of PAH-PAA complexes in solution. For the PAH-PAA complexes with a low ratio of PAA to PAH the PAH-PAA complexes have low-level cross-linking and are flexible. The resultant PAH-PAA/PSS films have a thin film thickness and smooth surface and exhibit a nonlinear deposition behavior where the amount of PAH-PAA complexes and PSS deposited in each deposition cycle are larger than in its previous cycle. The PAH-PAA complexes with a high ratio of PAA to PAH have high-level cross-linking and are rigid. The PAH-PAA/PSS films constructed from the rigid PAH-PAA complexes have a large film thickness and rough surface and exhibit a linear deposition behavior. Deposition of the PAH-PAA/PSS films was well characterized by quartz crystal microbalance, atomic force microscopy, and scanning electron microscopy. The thermally cross-linked PAH-PAA/PSS films can be released from substrate to form stable free-standing films by an ion-triggered exfoliation method. Meanwhile, positively charged PAH-PAA complexes can be LbL assembled with negatively charged PAH-PAA complexes with a molar excess of PAA to produce multilayer films. Use of polyelectrolyte-polyelectrolyte complexes as building blocks for LbL fabrication provides a facile way to tailor the structures of the resultant films by simply changing the structure of the complexes in solution.

Biofunctional and Biomimetic Polymer Brushes Prepared via Surface-Initiated Atom Transfer Radical Polymerization

Surface-initiated controlled radical polymerization is a powerful strategy to tailor the chemical and physical surface properties of materials. This article highlights recent work from the author's laboratory in which surface-initiated atom transfer radical polymerization is used to generate biofunctional and biomimetic surface coatings. Three examples will be discussed. The first two examples are based on the surface-initiated atom transfer radical polymerization of 2-hydroxyethyl methacrylate and (polyethylene glycol) methacrylate, which generates a polymer brush that suppresses non-specific adhesion of proteins and cells. These non-fouling brushes have been used to generate protein microarrays and to produce coatings that can promote endothelialization of implantable biomaterials. The third example describes the use of polyelectrolyte brushes as matrices to direct the mineralization of calcium carbonate.

Tunable Wettability by Clicking Counterions Into Polyelectrolyte Brushes

AbstractPolymer brushes have recently emerged as an extremely versatile way to modify surface properties in a robust and controlled way. The introduction of responsive polymers and block copolymers in polymer‐brush systems has also opened up new routes to ‘smart' surfaces with switchable surface properties. Here, the use of polyelectrolyte brushes as a supramolecular platform for the immobilization of a wide range of species, leading to a tunable wettability of substrates, is presented.

Preparation of MnO 2 nanoparticles by directly mixing potassium permanganate and polyelectrolyte aqueous solutions

Well-stable MnO 2 nanoparticles were prepared by directly mixing potassium permanganate and polyelectrolyte aqueous solutions, with the use of polyelectrolyte to serve both as a reducing agent and a protective agent. Such nanoparticles were characterized by transmission electron microscopy (TEM) and X-ray photoelectron spectra (XPS), and their growth kinetics was further traced by in situ UV–vis spectra.

Performance optimization of coagulant/flocculant in the treatment of wastewater from a beverage industry

This study investigated the effect of coagulation/flocculation treatment process on wastewater of Fumman Beverage Industry, Ibadan, Nigeria. The study also compared different dosages of coagulant, polyelectrolyte (non-ionic polyacrylamide) and different pH values of the coagulation processes. The effect of different dosages of polyelectrolyte in combination with coagulant was also studied. The results reveal that low pH values (3–8), enhance removal efficiency of the contaminants. Percentage removal of 78, 74 and 75 of COD, TSS and TP, respectively, were achieved by the addition of 500 mg/L Fe 2(SO 4) 3·3H 2O and 93, 94 and 96% removal of COD, TSS and TP, respectively, were achieved with the addition of 25 mg/L polyelectrolyte to the coagulation process. The volume of sludge produced, when coagulant was used solely, was higher compared to the use of polyelectrolyte combined with Fe 2(SO 4) 3·3H 2O. This may be as a result of non-ionic nature of the polyelectrolyte; hence, it does not chemically react with solids of the wastewater. Coagulation/flocculation may be useful as a pre-treatment process for beverage industrial wastewater prior to biological treatment.

Formation of gold nanoparticles and self-assembly into dimer and trimer aggregates

Gold nanoparticles synthesized by in situ chemical reduction of HAuCl 4 with the use of polyelectrolyte serve as reductant and stabilizer. At the same time, gold nanoparticles were observed self-assembly into dimer and trimer aggregates, which were evidenced by TEM. The nucleation and growth kinetics was characterized by in situ UV–vis experiment. A model was proposed to illustrate the formation mechanism.

Use of Polyelectrolyte Layer-by-Layer Assemblies as Nanofiltration and Reverse Osmosis Membranes

Measurements of ion transport and water flux across ultrathin multilayered membranes of polyelectrolytes were carried out under nanofiltration and reverse osmosis conditions. The polyelectrolyte membranes were prepared upon alternating electrostatic layer-by-layer adsorption of polyvinylamine (PVA) and polyvinyl sulfate (PVS) on porous supports. The pressure-driven transport of aqueous electrolyte solutions containing NaCl, Na2SO4, MgCl2, and MgSO4 in 1 and 10 mM concentration was investigated. For MgCl2 and MgSO4, a complete rejection was observed independently from the concentration of the feed solution and the pressure applied. For NaCl and Na2SO4, the rejections were 84 and 96% at 5 bar, and 93.5 and 98.5% at 40 bar, respectively. The hydraulic permeability of the composite membrane was 113.7 mL/(m2 h bar). It was only little affected by the presence of salt. At low and moderate pressure the membranes are suitable for water softening applications, while at pressures of 40 bar or higher they can be use...

Phosphate biosensor based on polyelectrolyte-stabilized pyruvate oxidase

In this work the development of a pyruvate oxidase-based phosphate biosensor is illustrated. The use of polyelectrolyte stabilized recombinant pyruvate oxidase in conjunction with a porous conductive carbon results in the development of a simple, reproducible and stable phosphate biosensor. The polyelectrolyte diethylaminoethyl-dextran or DNA was used as the enzyme stabilizer, and the resulting enzyme–polyelectrolyte complexes were physically adsorbed into the transducer, a highly porous and conductive carbon electrode, for the construction of the biosensor. The optimized biosensor exhibits high operational (67% remaining activity after 220 h) and storage (49% remaining activity after 24 weeks) stability, and very good sensor-to-sensor reproducibility. The optimized phosphate biosensor was used for the measurement of the phosphate ion activity in serum.

Use of polyelectrolyte for incorporation of ion-exchange groups in composite membranes for vanadium redox flow battery applications

Daramic (W.R. Grace, USA), which consists of ultra high molecular polyethylene, amorphous silica and mineral oil, is cross-linked with divinylbenzene (DVB) to obtain a composite microporous separator with modified properties. In the present study, poly(sodium 4-styrenesulfonate) (PSSS) (Aldrich Chemical Company, Inc., USA, mol. wt. ∼ 70 000) is used as a polyelectrolyte to impart cation-exchange capacity to the cross-linked Daramic. Incorporation of cation-exchange groups in this composite membrane results in a reduction in solvent transfer across the membrane when used in a vanadium redox cell. The ion-exchange capacity (IEC) of the new PSSS composite membrane is also evaluated. Due to the solubility of PSSS in water, the IEC of the membrane decreases initially when the membrane is soaked in water, but then stabilizes and remains unchanged after a few weeks. Water-transport measurements across the PSSS composite membrane show promising results compared with those across the untreated cross-linked Daramic separator. A detailed 13C nuclear magnetic resonance (NMR) and X-ray dispersive analysis has been carried out to confirm the incorporation of PSSS into the membrane.

Commissioning and Operation of Yau Kom Tau Water‐Treatment Works (Hong Kong) Using Direct Filtration

AbstractThe paper outlines the commissioning, performance trials, and operational experience of the direct‐filtration process at the Yau Kom Tau treatment works in Hong Kong.The commissioning tests established the capability of the treatment plant to produce water of the required potable quality. However, the contractual performance trials were carried out at a time when adverse raw water might be expected, in order to assess the overall attainment of guarantees on the treated water quality, filter run, and washwater percentage.Since the works became operational in November 1985, a number of incidents of raw water quality outside the design limits have been experienced. The use of polyelectrolyte was found to enhance the performance and reliability of the direct‐filtration process.The paper also reports the results of some optimization tests and comments on the overall performance of the plant compared with expectations at the time of design.

Use of polyelectrolyte complex‐stabilized calcium alginate gel for entrapment of β‐amylase

Calcium alginate gel stabilized with a polyelectrolyte complex (PEC) consisting of potassium poly(vinyl alcohol) sulfate (KPVS) and trimethylammonium glycol chitosan iodide (TGCI) was used for the immobilization of beta-amylase. The immobilization was made by gelling aqueous droplets of enzyme solution including both sodium alginate and KPVS in a CaCl(2) solution containing TGCI. The activity of the enzyme entrapped into the stabilized gel beads was evaluated by studying the batch reaction kinetics of enzyme-catalyzed hydrolysis of maltotetraose. Repeated kinetic measurements, totaling 18, were carried out at fixed time intervals. After each measurement the beads were stirred for 1 day in a freshly prepared 10 mM NaCl solution at 3 degrees C. It was found that the immobilized system remained stable without leading to a serious loss of the activity or to a large leakage of the enzyme from the support. This was explained as being due to a PEC-crosslinked contracted network structure of the stabilized gel matrix.

Regulation of water metabolism in hemodialysis; compensation and overcompensation of colloidosmotic pressure of blood through the use of polyelectrolyte containing dialysis solutions in artificial kidneys

Addition of polyelectrolytes, in particular of the sodium salt of carboxymethylcellulose, makes it possible to obtain for the use in artificial kidneys dialyzing liquids which are in thermodynamic equilibrium with blood, both with respect to salts and water, or which even permit removal of water from the blood, as well as urea and related substances (the dialyzing liquid being at will hypertonic with respect to blood), the salt content of blood remaining in all these cases unaffected. These dialyzing liquids might be particularly useful for cases combined with oedema.