Synthetic fibers, mainly polyethylene terephthalate (PET), polyamide (PA), polyacrylonitrile (PAN) and polypropylene (PP), are the most widely used polymers in the textile industry. These fibers surpass the production of natural fibers with a market share of 54.4%. The advantages of these fibers are their high modulus and strength, stiffness, stretch or elasticity, wrinkle and abrasion resistances, relatively low cost, convenient processing, tailorable performance and easy recycling. The downside to synthetic fibers use are reduced wearing comfort, build-up of electrostatic charge, the tendency to pill, difficulties in finishing, poor soil release properties and low dyeability. These disadvantages are largely associated with their hydrophobic nature. To render their surfaces hydrophilic, various physical, chemical and bulk modification methods are employed to mimic the advantageous properties of their natural counterparts. This review is focused on the application of recent methods for the modification of synthetic textiles using physical methods (corona discharge, plasma, laser, electron beam and neutron irradiations), chemical methods (ozone-gas treatment, supercritical carbon dioxide technique, vapor deposition, surface grafting, enzymatic modification, sol-gel technique, layer-by-layer deposition of nano-materials, micro-encapsulation method and treatment with different reagents) and bulk modification methods by blending polymers with different compounds in extrusion to absorb different colorants. Nowadays, the bulk and surface functionalization of synthetic fibers for various applications is considered as one of the best methods for modern textile finishing processes (Tomasino, 1992). This last stage of textile processing has employed new routes to demonstrate the great potential of nano-science and technology for this industry (Lewin, 2007). Combination of physical technologies and nano-science enhances the durability of textile materials against washing, ultraviolet radiation, friction, abrasion, tension and fading (Kirk–Othmer, 1998). European methods for application of new functional finishing materials must meet high ethical demands for environmental-friendly processing (Fourne, 1999). For this purpose the process of textile finishing is optimized by different researchers in new findings (Elices & Llorca, 2002). Application of inorganic and organic nano-particles have enhanced synthetic fibers attributes, such as softness, durability, breathability, water repellency, fire retardancy and antimicrobial properties (Franz, 2003; McIntyre, 2005; Xanthos, 2005). This review article gives an application overview of various physical and chemical methods of inorganic and organic structured material as potential modifying agents of textiles with emphasis on dyeability enhancements. The composition of synthetic fibers includes polypropylene (PP), polyethylene terephthalate (PET), polyamides (PA) or polyacrylonitrile (PAN). Synthetic fibers already hold a 54% market share in the fiber market. Of this market share, PET alone accounts for almost 50% of all fiber materials in 2008 (Gubitz & Cavaco-Paulo, 2008). Polypropylene, a major component for the nonwovens market accounts for 10% of the market share of both natural and synthetic fibers worldwide (INDA, 2008 and Aizenshtein, 2008). It is apparent that synthetic polymers have unique properties, such as high uniformity, mechanical strength and resistance to chemicals or abrasion. However, high hydrophobicity, the build-up of static charges, poor breathability, and resistant to finishing are undesirable properties of synthetic materials (Gubitz & Cavaco-Paulo, 2008). Synthetic textile fibers typically undergo a variety of pre-treatments before dyeing and printing is feasible. Compared to their cotton counterparts, fabrics made from synthetic fibers undergo mild scouring before dyeing. Nonetheless, these treatments still create undesirable process conditions wh
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Understanding sludge rheology and optimizing equipment performance is crucial for energy efficiency in wastewater treatment plants (WWTPs). This study examined sludge rheology after thermal hydrolysis pretreatment (THP) at 60, 80, and 120 ◦C for 2 h, followed by anaerobic digestion (AD) at 37 ◦C for 20 days, and assessed impacts on pump and agitator performance. Post-treatment, sludge showed reduced viscosity and improved flowability, indicated by changes in Herschel-Bulkley parameters, enhancing pump and agitator efficiency, particularly at 120 ◦C. These rheological improvements were correlated to the solubilization of sludge components after THP and solids reduction after AD, highlighting the interconnectedness of rheology and treatment outcomes. Despite high heat demands, an energy balance showed that THP scenarios, especially at 120 ◦C, had lower energy requirements for pumps and agitators, leading to energy savings without increased heat consumption. These findings underscore the influence of rheological changes in improving energy efficiency in WWTPs.
This paper presents three lesson activities for upper secondary education that focus on learning subject specific knowledge and general system thinking skills by creating a qualitative representation. The learning goals and the pedagogical approach are described.
Dit projectvoorstel is gericht op de ontwikkeling van nieuwe moleculen om zelf, thuis infectieziekten te diagnosticeren. Om de diagnose van infectieziektes te bevorderen, met name in afgelegen gebieden, is de innovatieve strategie van point-of-care (POC), een snelle, accurate en sensitieve diagnostische test die door een patiënt zelf kan worden uitgevoerd, uitermate geschikt. Een simpel en klein toestel dat enzymatische activiteit uit microben kan meten is in ontwikkeling bij Enzyre B.V. Dit voorstel gaat over de ontwikkeling van nieuwe lichtgevende moleculen die de detectie van infectieziektes kunnen aantonen door middel van het Enzyre platform. Hiervoor wordt een nieuwe chemisch aanpak om dit soort lichtgevende moleculen te maken ontwikkeld. Dit is relevant voor de preventie en het monitoren controle van potentiële pandemieën zoals bijvoorbeeld de recente uitbraak van SARS-Cov-2, maar ook MERS, SARS, HIV, Ebola en meerdere influenza pandemieën uit het verleden
About 35-40 kton used mattresses available yearly for the recycling only in the Netherlands. Mattresses that are offered at recycling companies, municipal yards and retailers often find their way to incinerators. However, several fraction components of used mattresses can be reused/resale in a useful manner. One of the mattress fractions is textile cover with residue of Polyurethane (PU) foam. Effective removal of PU foam would enable further reuse of textile materials. Use of harsh chemicals/ thermo-, photo-, oxidative, processes including hydrolysis, aminolysis, phosphorolysis, glycolysis etc [1,2] for PU foam degradation is not a good solution, since it will cause non-specific damage to textiles and other parts, making recycle/ reuse difficult. Therefore, Mattress Recycling Europe BV (MRE) is looking for an eco-friendly mild process for selective degradation of PU foam component. PU is a mixed polymer; therefore, it is important to establish the physio-chemical nature of PU before identifying suitable and sustainable degradation route. The proposed solution is selective degradation of PU polymer using biotechnology. Enzymatic bio-catalysis enables a targeted, specific reaction at mild process conditions (pH, temperature) without harming other components in the process. Primarily hydrolase class of enzymes is assumed to be among the most effective options for the proposed degradation of PU foam residue [3,4]. From previous research, adding mechanical shear provides a synergistic effect for enzyme catalysed reaction [5-7]. Therefore, within the scope of this exploratory practice-oriented project, technical feasibility of bio-catalyst and shear (including well established PU degradation techniques) towards the selective degradation of PU foam residue attached to textile part from used mattresses will be explored together with cost estimation of the overall process and re-usability of enzymes using suitable immobilisation technique, addressing an urgent industrial need in the field of green chemistry.
