Effects Of Water Properties Research Articles

Coagulation of TiO2 , CeO2 nanoparticles, and polystyrene nanoplastics in bottled mineral and surface waters. Effect of water properties, coagulant type, and dosage.

Intensive use of engineered nanoparticles (NPs) results in their release into aquatic systems and consequently into drinking water resources. Therefore, it is important to evaluate how NPs can be effectively removed through water treatment processes, such as coagulation, to control environmental and health risks associated with NP exposure. This work investigates the effect of two conventional coagulants, polyaluminum chloride (PACl) and iron chloride (FeCl3 ), on NPs. Three bottled mineral and Lake Geneva waters, currently used as drinking water resources, were considered to get an insight into coagulation efficiency. TiO2 , CeO2 NPs, and polystyrene (PS) nanoplastics were selected, owing to their large number of applications and contrasting surface charge and aggregation behavior at environmental pH. Our findings indicate that PACl is more efficient compared with FeCl3 since lower dosages are required to coagulate all nanoparticles. On the other hand, nanoplastic coagulation is found less efficient compared with TiO2 and CeO2 NPs. This is an important outcome indicating that nanoplastic stability and dispersion state will be more pronounced and therefore more challenging to eliminate. Results highlight the key role of NP and PS nanoplastic surface charge, as well as water properties, coagulant type, and dosage on nanoparticle elimination from aquatic systems. PRACTITIONER POINTS: pH, water hardness, and NOM are playing roles in final coagulant dosage concentration. PACl is more efficient than FeCl3 in most conditions. Positively charged nanoplastics are more difficult to eliminate by coagulation. NP surface properties in bottled mineral and surface waters are controlled by pH, divalent cations, and NOM. NP surface charge and coagulation efficiency depend on water properties.

Solid Acid/Base Catalysis in Sub- and Supercritical Water

Solid acid/base catalysis in sub- and supercritical water (Sub&SCW) is a promising method to control organic reactions such as biomass conversions to chemicals and fuels, organic synthetic reactions, and degradation reactions. Synergistically using the unique characteristics of Sub&SCW and the catalytic properties of solid acid/base compounds, high reaction rates and/or high product selectivity can be achieved. This Review provides an overview of the use of solid acid/base catalysts for Sub&SCW reactions. Recent progress in the elucidation of the acid/base catalytic properties of solid catalysts in Sub&SCW and the effect of water properties on the catalysis is introduced. In addition, the application of solid acid/base catalysts in several research fields and the stability of these catalysts during reactions is discussed.

Effect of water properties on selectivity for 1-octene and 2-octanol reaction systems in sub- and supercritical water using a TiO2 catalyst

The effect of water properties on solid acid catalysis using TiO2 as the catalyst in sub- and supercritical water was elucidated using the reactions of 1-octene and 2-octanol as models. Kinetic data for these reactions at 290–410°C and 25MPa were analyzed, and relationships between reaction selectivities and water properties were evaluated quantitatively. The cis/trans selectivity for 2-octene produced in reactions of both 1-octene and 2-octanol drastically increased at around the critical temperature of water, and was quantitatively explained using the model of acid catalysis in sub- and supercritical water derived from kinetic analyses. The hydration selectivity of 1-octene conversion had a local maximum at around 330°C, which was explained by considering the change in reactivity of water as a reactant caused by changes in both water density and the degree of hydrogen bonding.

Use of Water Properties in Food Technology: A Global View

Water is a major component of drinking water, beverages, and most foodstuffs. In this study, an effort has been made to employ selected properties of water for: (1) evaluation of interactions of water with other food components; (2) discussion on the effects of water properties on food and beverage products; (3) applications of water properties in food technology; and (4) comparison of water properties with corresponding properties of similar substances. This study provides the following major conclusions: (i) unusual properties of water are mostly due to its high permanent dipole moment, partial ionic character of O–H covalent bonds, and extensive hydrogen bonds; (ii) different properties of many foodstuffs are strongly related to various properties of water; (iii) the properties of food products change depending on water availability and temperature; (iv) preparation of drinking water is a prerequisite for production of any safe drinks and foodstuffs; (v) water contributes important roles in quality, flavor, and shelf-life of foods; and (vi) water is used in food industries as a fluid for heat transfer; as a medium for temperature moderation in food processing; as a solvent for sugars, salts, water-soluble vitamins, and acids; as a dispersing agent for hydrophilic food components; as a dispersed phase for emulsified products; or as a reactant for several reactions in food processing.

Effect of water properties on the degradative extraction of asphaltene using supercritical water

Abstract An extraction method was used to optimize the miscibility of supercritical water (SCW) with asphaltene (AS) at 400–450 °C and 20–35 MPa. The optimal temperature for the determination was 440 °C due to the improved balance between solubility and the coking rate. With increasing the pressure at 440 °C, the degradative extraction yield of AS using SCW reached a maximum at around 30 MPa. The extraction behavior was thought to be controlled mainly by the water properties represented by the dielectric constant (DC) and Hansen solubility parameter (HSP). These properties affected the miscibility with AS and consequently the extraction yield. As a result, the optimal water properties to achieve the highest miscibility with AS were DC = 2.2, δp = 6.4, and δh = 9.7.

538 Study on Eco-Friendly Oil on Water Drop Cutting Fluid : Water Properties and Machining Performance of Oil on Water Drop Cutting Fluid

A new ecological-cutting fluid application in which relatively large water particles covered with thin oil ilm are sprayed on a machining point was developed and is being modified by authors. This method is called an Oil-on-Water drop cutting fluid; abbreviating to "OoW". The OoW achieves both effective lubrication and strong cooling performance as well as conformability to environmental issue. An oil mass ratio to the OoW cutting fluid is only around 1%. That is, the OoW cutting fluid almost consists of water, and then it should be said that effects of water properties on cutting performance is worth investigating. In this paper it is noted how calcium concentration in water, which roughly represents hardness of water in the case of tap water, influences cutting performance. For this purpose variation of cutting force with the hardness of water is experimentally investigated on two kinds of oil. In the case of vegetable oil the cutting force is considerably reduced with the hardness of water while, in the case of synthetic biodegradable ester with surface active agent, the hardness of water has almost no influence.