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Digital Printing
Published in Asim Kumar Roy Choudhury, Principles of Textile Printing, 2023
Surface tension is one of the most important properties of inkjet inks for textile applications. It has been suggested that surface tension of ink is a primary factor determining droplet formation and spreading on the substrate upon contact (Magdassi, 2010). Ideally, inkjet inks should have a surface tension in the range of 25–60 dynes/cm (Ujiie, 2006,). Surface tension can be controlled by using surfactants and by selecting proper solvent compositions. For example, adding propanol to water will cause a large decrease in surface tension, from 72.8 dyne/cm to below 30 dyne/cm, depending on the propanol concentration. Surface tension of the inks must be in the range of 25–60 dynes/cm, so that it wets the capillary channels, flows through the nozzle and forms the droplets correctly to ensure proper jetting (Le, 1998; Ali, 2008). Surfactant – also called surface-active agent – is a substance such as a detergent that, when added to a liquid, reduces its surface tension, thereby increasing its spreading and wetting properties. In the dyeing of textiles, surfactants help the dye penetrate the fabric evenly (Mallinson, 1999). They are used to disperse aqueous suspensions of insoluble dyes and perfumes. The surfactant possesses two different chemical groups, one compatible with the liquid to be modified, and the other having a lower surface tension. Typically, 1% or less is sufficient enough to efficiently lower the surface tension of inks, coatings and paints (Mallinson, 1999).
Activated Sludge Process for Refractory Pollutants Removal
Published in Maulin P. Shah, Removal of Refractory Pollutants from Wastewater Treatment Plants, 2021
Reyhan Ata, Gökçe Faika Merdan, Günay Yıldız Töre
Perfluorooctane sulfonic acid (PFOS), its salts, and perfluorooctane sulfonyl fluoride (PFOS-F) fulfills the criteria of the Stockholm Convention Annex B (Restriction) list as refractory (persistent, bio-accumulative, and toxic) chemicals with extensive industrial application. They are man-made (synthetic), non-biodegradable, and striking in terms of the strength of organic pollution created in the receiving environment where it is discharged without treatment. They do not occur naturally in the environment and are known as surfactants or fluorosurfactants [perfluorooctanoic acid (PFOA)]. Surfactants are compounds that reduce the surface tension (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. Surfactants have the ability to play the role of detergent, wetting agent, emulsifier, foaming agent, and dispersant. The volume of surfactants (through detergents, cleaning agents, and PPCPs) released into the environment at a rising rate are becoming an increasing concern. Linear alkylbenzene sulfonates (LAS) (used for detergent production) and alkyl phenol ethoxylates (APE) (used for detergent-like compounds production), known as the two basic surfactants, break down into nonylphenol, which is considered an endocrine disruptor in sewage treatment plants and soil (Rebello et al. 2014).
Establishing Miscanthus, Production of Biomass, and Application to Contaminated Sites
Published in Larry E. Erickson, Valentina Pidlisnyuk, Phytotechnology with Biomass Production, 2021
Lawrence C. Davis, Valentina Pidlisnyuk, Aigerim Mamirova, Pavlo Shapoval, Tatyana Stefanovska
Surface-active compounds. Surfactants are chemical compounds that decrease surface tension. Surfactants can reduce the hydrophobicity of organic compounds, for example, nonionic surfactants decreased the hydrophobicity of polychlorinated biphenyls in a soil-water system (Park & Boyd, 1999). There are surfactants of chemical (Tweens, Polysorbate, Triton) and biological (e.g., rhamnolipids) origins. Gonzalez et al. (2010) reported that adding Tween 80 (nonionic) to contaminated soils effectively enhanced p,p-DDT, p,p-DDE, and α-cypermethrin solubility while adding sodium dodecyl sulfate (anionic) increased the solubility of two other pesticides (α-endosulfan and endosulfan sulfate).
Review on performance analysis in diffusion absorption refrigeration system (DARS) using different working fluids
Published in International Journal of Ambient Energy, 2023
Sreenesh Valiyandi, Gireeshkumaran Thampi
Wu et al. (2020) addressed the Comparative analysis of conventional and low-GWP refrigerants with the ionic liquid used for assisted-compression absorption cooling cycles. Problems of conventional absorption methods, hydrofluorolofins/hydrofluorocarbons with low global warming potential, and ionic fluids at low temperatures for two assisted absorption-compression are numerically investigated. Surfactant is one of the temporary chemical treatment methods for improving absorption. Surfactants are known as compounds that reduce surface tension between two liquids. Kim et al. (2006) used a shadow graphic technique to inspect surfactants’ effects and analyse the bubble behaviour. 2-Ethyl-1 Hexanol was the most effective because its absorption rate was 4.81 times more. The addition of surfactant (2-ethyl-1-hexanol 700 ppm) and Nano-particle (Cu, 0.1%) improved the absorption efficiency up to 5.32 times through their continued research.
The transmission mode of Legionella from water
Published in Environmental Technology, 2022
Jun Li, Lin Liu, Jiayong Zhang, Hanyi Li, Kunquan Li, Zhihua Dou, Xuebin Li, Tao Tao
Our results show that Legionella can be removed by water, but cannot escape from water by air, vapour, steam, or aerosol. The possible reasons are analyzed below. Water is a polar molecule and has a bent molecular geometrywith two hydrogen atoms on the oxygen vertex. In the following analysis, a water molecule is assumed to have the following characteristics: the H–O–H gas phase bend angle is 104.48°, as shown in Figure 5 (a), and the distance between the O and H is 95.84 pm [23,24]. The positive hydrogen ends connect to the negative oxygen end to form a water molecule. The cohesive force among many water molecules leads to surface tension, and significant energy is needed to break these intermolecular bonds. Surface tension is also defined as the property of a liquid surface that resists an external force. There are no water molecules above the water surface, resulting in a stronger bond between the molecules in the surface than in the internal body of liquid. This surface layer creates a considerable barrier between air and water.
Stability analysis of environmentally benign green emulsion liquid membrane
Published in Journal of Dispersion Science and Technology, 2018
Anil Kumar, Avinash Thakur, Parmjit Singh Panesar
Surfactants are the substances which reduce the interfacial surface tension between the two liquids and widely used in various industries for making emulsions. Surfactants are added to the GELM to prevent the release of stripping agent (NaOH) from the stripping phase by forming a barrier between the internal and feed phase.[28] Surfactants are the most important constituent of membrane phase which help in forming the water emulsion in oil (W/O) by reducing the interfacial tension between oil and water by getting adsorbed at the liquid-liquid interface, and also ensures good emulsion stability.[29,30] Surfactants are usually organic amphipathic compounds and soluble in both organic solvents as well as in water. The effect of span-80 concentration on the visual static stability of GELM has been studied and shown in Figure 4. It can be observed that with the increase in span-80 concentration (1-2 v/v, %), the visual static stability of GELM has increased (90 ± 2 to 118 ± 2 min) but beyond 2% (v/v), it has started to decline (118 ± 2 to 20 ± 2 min). GELM has shown the highest visual static stability (118 ± 2 min) at 2 (v/v, %), span-80 concentrations. For high values of span 80 concentration, GELM has shown the poor visual static stability due to increase in swelling rate with the increase in span-80 concentration.[31]