Microbiology and slime control in papermaking

Snaha po zefektivnění výroby papíru spojená s úsporou energií a materiálových nákladů vede ke stále většímu uzavírání vodních okruhů papírenských strojů resp. k snižování spotřeby čerstvé a vypouštěné vody. Na druhé straně však toto vyvolává zvyšování teploty a koncentrace rozpuštěných, koloidních a dalších rozdispergovaných látek. Výsledkem je pak zvyšováni dávek pomocných aditiv a růst slizů. Slizy způsobují problémy v chodu papírenského stroje, protože vytváří nepříjemné usazeniny, korozi atd. Kontrola slizů tak nabývá v oboru výroby papírů a lepenek čím dal vice na významu.Aiming for more efficient paper production associated with savings of energy and material costs lead to increasing closure of water circuits of paper machines or to reduce the consumption of fresh and discharged water. On the other hand, however, this raises the temperature and increases the concentration of dissolved, colloidal, and other dispersed substances. This results then in increasing doses of auxiliary additives and growth of slime. Mucilaginous slimes are causing problems in the runability of the paper machine, because it creates an unpleasant build-up of deposits, corrosion etc. Slime control so takes in the paper and board production more and more in importance

Bilayers as Basic Formation of Epimolecular Structure of Mostly Lyotropic (Hydrotropic) Structuralized Liquid Systems Being Influenced Predominantly by the Temperature

The bilayer’s formations of amphiphilic molecules or polyions of different ionogenity comprise the basic building units of most organic biological and non-biological systems. A theory has evolved to explain their behaviour during the creation of those organized structures, such as anisotropic liquid crystal (LC) in lyotropic (especially hydrotropic) systems and polyelectrolyte multilayer (PEM) assemblies. Particular attention has been paid to the temperature and the important role of water in the formation and behaviour of the bilayers. A novel insight into the formation of hydrotropic liquid LC systems and their thermotropic behaviour is presented. In this context, the systems PEM assemblies are also discussed. Essentially, a structuralised form of water fills out continuous and discontinuous, i.e., confined, nano-spaces among hydrophilic interfaces of bilayers, controlling their supramolecular structure through a system of attractive and repulsive hydration forces. The character of those sophisticated bonding hydration systems is predestined by the composition and type of these hydrophilic interface groups. The miscellaneous complexity of the bilayer’s aqueous systems suggests the need to study these examples in greater detail. Therefore, the bilayer’s processes connected with disruption as far as destruction of bilayers are mentioned, i.e., the processes with the highest potential to combat bacteria, fungi, and viruses, such as in a situation where a person exhales a breath of micro-droplets containing virus nanoparticles (e.g., the COVID-19 virus)

Separace Cd2+ iontů z vody za použití oxycelulóz a aktivované buničiny

Natural cellulose and carboxyl celluloses are highly hydrated substances with interesting sorption behaviour. They have the similar chemical composition, but different size of molecules and representation of COOH groups organized into a complex of supramolecular structure. Separation of Cd2+ from polluted water by use of oxycellulose (OC) hydrocolloid fibrous form was compared with dissolved carboxyl methylcellulose (CMC). The carboxyl celluloses adsorption capacity of Cd2+ ions increases with increasing of –COOH group content and distinctly increases with other competitive ions in the aqueous solution. The dissolved and hydrocolloid fibrous forms of carboxyl celluloses were separated from water by use of pulp fibre in both activated and inactivated form as a scavenger. It was revealed that for factual separation efficiency static (i.e. rheosedimentation) or dynamic (i.e. drainage fiber suspension) conditions of the scavenger application evoking counter character of the separation behavior are most important.V práci byla studována separace Cd2+ iontů ze znečištěné vody s použitím hydrokloidní vláknité formy oxycelulózy (OC) a tato byla porovnána s rozpuštěnou karboxymethylcelulózou (CMC)

Mechanismus separace těžkých kovů z vody pomocí derivátů karboxy-celulózy

A mechanism of CS (Colloid – Sorption filtration) and CSF (Colloidal-Sorption – Filtration) separations are dynamic processes where, depending on intensity of media flowing in filter pores, also shear forces participate on trapping process of hydro-colloid particles. The adsorption capacity of cellulose carboxyl derivatives increases with increasing –COOH group content and is distinctly increased by the presence of other competitive ions in the aqueous solution.Mechanismy CS (koloidní separace) a CSF (koloidně - sorpční filtrace) jsou dynamické procesy, kde se v závislosti na intenzitě média proudícího v pórech filtru účastní také smykové síly při zachycování hydro-koloidních částic. Adsorpční kapacita karboxylových derivátů celulózy se zvyšuje se zvyšujícím se obsahem skupiny COOH a je zřetelně zvýšena přítomností jiných konkurenčních iontů ve vodném roztoku

Oxidized Cellulose with Different Carboxyl Content: Structure and Properties before and after Beating

AbstractOur recent studies concentrated in investigating influence of beating oxidized cellulose, with different carboxyl content, on changing their basic properties (degree of polymerization, WRV - water resistant value and X-ray diffraction). Cellulose samples of oxidized cellulose were beated by toroidal beating machine.Cellulose consists of both amorphous and crystalline regions. Cellulose consists of linear chains of poly[ß-1,4-D- anhydroglucopyranose] (C6nH10n + 2O5n + 1 (n = degree of polymerization of glucose)), which crystallize through hydrogen bonding between the chains and has cellobiose as repeat unit. Oxidized cellulose is preparing by oxidation of cellulose in the C6 position of the glucopyranose units to carboxylic group (-COOH) and polyanhydroglukuronic acid (PAGA) is arised. An other option is oxidation with sodium hypochlorite with catalytic amounts of sodium bromide and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) under various conditions.Beating and refining or mechanical treatment of fibers in water is an important step in using pulps for papermaking. It is an energy intensive process. The purpose of the treatment is to modify fiber properties to obtain the most desirable paper machine runnability and product properties. End of beating pulps was characterized by position, when all beated pulps under mixture passed through of riddle (about sizes mesh of 50).During beating of samples about different ratio of oxidation it was found, that samples with higher contents of COOH groups in starting pulp are characterized by a significantly lower specific beating energy consumption needed to achieving the same sizes of particles. X-ray analyse shows that for non-beated oxidized cellulose was perceptible high share amorphous contents compared with beated oxidized cellulose

Surface Flocculation as a New Tool for Controlling Adsorption Processes

The dyeing of modified pulp, particularly with regard to the mechanism involved, was studied. The reaction mechanism for the modification of cellulose fibres in aqueous solution by cationic agents was also described. The results obtained were expressed in the form of adsorption isotherms. The capture of molecules, colloidal particles, etc. during the adsorption processes involving modified pulp could be explained by two possible mechanisms: (i) aggregation (coagulation or flocculation) in solution followed by adsorption and (ii) surface aggregation (coagulation or flocculation). Surface aggregation appeared to be the most likely for pulp with a low degree of modification. The typical Langmuir adsorption isotherm correlated the data obtained for unmodified pulp very well

Adsorption Characteristics of Oxycellulose in a Competitive Environment with other Substances

A comparison was undertaken of the sorption response of oxycellulose and initial linters, i.e. the short fibres that adhere to cotton seed after ginning, towards Fe 2+ , Ca 2+ and Cd 2+ ions in fibrous slurries. The exceptional adsorption capability of oxycellulose towards metal ions (particularly Cd 2+ ions) was confirmed. However, such adsorption processes are quite complicated and are influenced by the solubility of oxycellulose, its composition and the character of the components released into the supernatant, as well as by the presence of other competitive substances and ions in the aqueous solution. The adsorption capacity of oxycellulose increases with increasing –COOH group content and is distinctly increased by the presence of other competitive ions in the aqueous solution. Most probably, this enhanced adsorption capacity of the support bears some analogy to the superficial aggregation (flocculation) induced by the presence of foreign substances

Společná absorpce par vody a esenciálních olejů lignocelulózovými materiály - verifikace naměřených dat

Competitive absorption process, i.e. condensation, of water and essential oils (EO) are predominantly controlled by extent of condensation of diffusing water and EO molecules with marginal influence of porous lignocellulosic matter and a sort of EO. With increase of absorption the diffusion is depressed and vice versa. Diffusion of water molecules through porous system is usually slower in comparison with other molecules. It was discovered, a presence of EO decreases paper web humidity with increasing influence in environment with high relative air humidity. Evaluation of measured values using mathematical growth models, offers an infinite number of solutions for the ratio of water vapour and EO vapour absorption capacities, which in total gives the overall measured absorption capacity. It is necessary to find the right solution. One possibility is e.g. the measurement of water content in the sample after the experiment, or using the methodology described in this paper.Práce se zabývá směsnou absorpcí par vody a esenciálních olejů do lignocelulózových materiálů a studiem její kinetiky gravimetrickou metodikou. Je zde navrženo vyhodnocení podílů zkondenzovaných par vody a par esenciálního oleje v pórech lignocelulózového materiálu z celkového množství zkondenzovaných par

Methodology for application of essential oils and their components for creation of fungistatic effect in repositories of paper artifacts endangered by microbiol attack caused by increased relative humidity

Cílem metodiky je na základě získaných vědomostí, tj. empirických poznatků i teoretických znalostí o jevech souvisejících s interakcemi papírová hmota - páry esenciálních olejů, shrnout zásady a vypracovat postupy, jak tyto látky nebo jejich uměle připravené analogy používat, aby jejich aplikace pro zabránění mikrobiologického rozkladu papírových artefaktů byla maximálně efektivní s minimálními negativními dopady na papírové artefakty

Separace iontů Cd2+ pomocí oxycelulózy a aktivované buničiny

Natural cellulose and carboxyl celluloses are highly hydrated substances with interesting sorption behaviour. They have the similar chemical composition, but different size of molecules and representation of COOH groups organized into a complex of supramolecular structure. Separation of Cd2+ from polluted water by use of oxycellulose hydrocolloid fibrous form was compared with dissolved carboxyl methylcellulose.Práce studie možnosti separace kademnatých sloučenin pomocí oxycelulózy a aktivované buničiny ze znečištěných vod