Flocculation of cationic polymers and nanosized particles

Larsson, Anders; Walldal, Charlotte; Wall, Staffan

doi:10.1016/s0927-7757(99)00163-6

Cited by 32 publications

(13 citation statements)

References 17 publications

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“…Polymer characteristics of importance to polymer bridging are molecular weight and the molecular structure, as large molecules with long tails are capable of catching by-passing particles relatively easily. Charge density is also important, as this affects the number of loops and tails that are formed and the interaction between polymer and particles (Larsson et al, 1999;Ashmore and Hearn, 2000;Bouyer et al, 2001). …”

Section: Theorymentioning

confidence: 99%

Solid—liquid separation of animal slurry in theory and practice. A review

Hjorth

Christensen

et al. 2010

Agron. Sustain. Dev.

338

235

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-Animal slurry contains plant nutrients that are essential for crop production. However, intensive livestock production may lead to a surplus of plant nutrients on farms and, as a consequence, discharge or emission to the environment. In order to ensure that the slurry applied to fields matches the nutrient requirements of the crops, techniques have been developed to reduce the nutrient content of slurry by means of separation. This review discusses the separation technologies used for animal slurry treatment and the physical and chemical processes involved in separation. These processes need to be understood before efficient, reliable and cheap separation technologies that take into account the actual properties of slurry and the likely end-use of the separation products can be developed. A simple separation efficiency expression can be used to assess the efficiency of slurry separation. It is indeed important to measure the amount and composition of the slurry before treatment, the dry-matter-rich fraction and the liquid fraction. The separation efficiency of mechanical separators for the removal of dry matter and phosphorus (P) is ranked as follows: centrifugation > sedimentation > non-pressurized filtration > pressurized filtration. In general, the separation of total N and NH + 4 follows the same pattern, but the separation efficiency is lower than for dry matter and P. Treatment with a flocculant before separation improves separation efficiency significantly. Of the polyacrylamide polymers tested, high-molecular-weight, linear cationic polymers with a medium charge density (20-40 mol%) were found to be the most efficient flocculants. The best mechanical separation techniques for flocculated slurry are screens or filter belts. The separation efficiency of polyacrylamide-treated slurry can be improved by adding a multivalent ion to coagulate particles and for precipitation of phosphorus. Aluminium sulfate (Al 2 (SO 4 ) 3 ) or ferric chloride (FeCl 3 ) seem to be very efficient for improving the mechanical separators. Alternatively, the mineral struvite (MgNH 4 PO 4 ) may be formed by changing the slurry characteristics, such as by the addition of magnesium (Mg) or by increasing the pH to 9. The struvite crystals are removed during solid-liquid separation. The products of the solid-liquid separation may be further treated by evaporation, membrane filtration or ammonia stripping in order to obtain the desired end-products; however, low-maintenance and/or cost-efficient operation of these post-treatments has not yet been demonstrated. The separation should be developed as a whole-system approach, paying attention to parameters such as the value of end-products, environmental consequences and economy.

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Section: Theorymentioning

confidence: 99%

Solid—liquid separation of animal slurry in theory and practice. A review

Hjorth

Christensen

et al. 2010

Agron. Sustain. Dev.

338

235

View full text Add to dashboard Cite

show abstract

“…There are several reports about the phenomena of nanoparticles-based flocculation by charged polymers [217][218][219][220][221][222][223]. Although extensive experimental and theoretical works are reported for understanding the flocculation processes and construct nanoparticles-based flocculated materials with controlled structures, studies for pH-responsive phenomena of nanoparticles-based flocculated materials were limited.…”

Section: Metal Nanoparticles Modified With An Ionic Liquid Moietymentioning

confidence: 99%

Nanohybridized Synthesis of Metal Nanoparticles and Their Organization

Naka

Chujo

2009

Nanohybridization of Organic-Inorganic Materials

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Metal nanoparticles have various unusual chemical and physical properties compared with those of metal atoms or bulk metal due to the quantum size effect and their large superficial area, which make them attractive for applications such as optics, electronics, catalysis, and biology [1,2]. The catalytic properties of metal nanoparticles have generated great interest over the past decade. Among various metal nanoparticles, gold nanoparticles have tremendously high molar absorptivity in the visible region. Particle aggregation results in further color changes of gold nanoparticles solutions due to mutually induced dipoles that depend on interparticle distance and aggregate size. This phenomenon can be applied to various sensing systems [3][4][5][6][7]. The assembly of gold, silver, or copper nanoparticle monolayers is one of the ideal substrate for surfaced-enhanced Raman scattering (SERS) [8,9].Bare metal nanoparticles are prepared by employing physical methods such as mechanic subdivision of metallic aggregates and evaporation of a metal in a vacuum by resistive heating or laser ablation. Chemical methods such as the reduction of metal salts in solution are the most convenient ways to control the size of the particles and modified the surface chemical composition. To exploit nanoparticle properties for future device fabrication, self-organization of nanoparticles in a controlled manner is required. To construct such devices, new fabrication techniques must be developed with suitable metal nanoparticle-based building blocks. Several patterns for self-assemblies of the metal nanoparticles are schematically illustrated in Fig. 1.1. A number of outstanding reviews on the synthesis and assembly of metal nanoparticle-based building blocks have appeared [2,10]. This chapter highlights recent fabrication techniques of hybrid metal nanoparticles by controlled self-organization of the metal nanoparticle-based building blocks. Design of nanoparticle hybrids will be first focused on using building blocks for further assemblies. Several recent efforts have been concentrated on a system that

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“…The wide application possibilities of stabilizing and flocculating properties of polymers in industry, agriculture, environment protection, and other areas are the reason for the great interest in the phenomenon of macromolecule adsorption on the dispersed solid surface 9–14 . For this reason, research on polymer adsorption on the solid–solution interface is of theoretical and practical importance.…”

Section: Introductionmentioning

confidence: 99%

Temperature Study of Nonionic Polymers Adsorption at the Alumina—Solution Interface

Wiśniewska¹

2007

Journal of the American Ceramic Society

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The temperature influence of the structures of polyvinyl alcohol (PVA) and polyethylene glycol (PEG) adsorption layers on the alumina surface was studied. The amount of polymer adsorbed, the surface and diffuse layer charge of Al 2 O 3 particles in the absence and presence of the polymer, and the thickness of polymer adsorption layers were determined in the 51-401C temperature range. An increase of PVA and PEG adsorption with an increase of temperature was observed. It is caused by conformation changes of polymer macromolecules from the coil structure to more and more stretched conformation when the temperature increases. Such a behavior was confirmed by the parameters calculated from the experimental data (R h -hydrodynamic radius of a polymer coil in the solution, d-thickness of the polymer adsorption layer, R s -radius of a sphere equivalent to the volume that falls per a macromolecule in the adsorbed layer). From the comparison of the values of diffuse layer charge and surface charge, the main factor influencing the f potential changes was determined. The free energy of PVA and PEG adsorption was calculated using the f potential data.

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Flocculation of cationic polymers and nanosized particles

Cited by 32 publications

References 17 publications

Solid—liquid separation of animal slurry in theory and practice. A review

Solid—liquid separation of animal slurry in theory and practice. A review

Nanohybridized Synthesis of Metal Nanoparticles and Their Organization

Temperature Study of Nonionic Polymers Adsorption at the Alumina—Solution Interface

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