Direct measurement of the viscoelectric effect in water

The viscoelectric effect concerns the increase in viscosity of a polar liquid in an electric field due to its interaction with the dipolar molecules and was first determined for polar organic liquids more than 80 y ago. For the case of water, however, the most common polar liquid, direct measurement of the viscoelectric effect is challenging and has not to date been carried out, despite its importance in a wide range of electrokinetic and flow effects. In consequence, estimates of its magnitude for water vary by more than three orders of magnitude. Here, we measure the viscoelectric effect in water directly using a surface force balance by measuring the dynamic approach of two molecularly smooth surfaces with a controlled, uniform electric field between them across highly purified water. As the water is squeezed out of the gap between the approaching surfaces, viscous damping dominates the approach dynamics; this is modulated by the viscoelectric effect under the uniform transverse electric field across the water, enabling its magnitude to be directly determined as a function of the field. We measured a value for this magnitude, which differs by one and by two orders of magnitude, respectively, from its highest and lowest previously estimated values.

Donor-Acceptor Based Solvent-free Organic Liquid Hybrids with Exciplex Emission and Room Temperature Phosphorescence

Solvent-free organic liquids have been known for their excellent luminescent features. Hence, the recent developments in this area have marked them as potential emitters with high quantum yield and enhanced...

Risk assessment and remediation of NAPL contaminated soil and groundwater

The presence of water-immiscible organic liquids—commonly called non-aqueous phase liquids or NAPLs—in soils and groundwater, is a worldwide environmental problem. Typical examples of NAPLs include: petroleum products, organic solvents and organic liquid waste from laboratories and industry. The molecular components of NAPLs present in soils, rocks and groundwater are readily transferred to the vapour and aqueous phases. The extent to which they do this is determined by their solubility (which is quite limited) and vapour pressure (which can be quite high). These molecular components, once dispersed in the vapour phase or dissolved in the aqueous phase, can provide a long-term source of harm to biotic receptors. The object of this lecture text is to examine how we can assess the degree of harm using quantitative risk assessment and how NAPL contaminated environments can be restored through the use of chemical, biological and physical remediation technologies. Graphical abstract

Validation of the Decontamination of a Specialist Transport System for Patients with High Consequence Infectious Diseases

When transferring highly infective patients to specialist hospitals, safe systems of work minimise the risk to healthcare staff. The EpiShuttle is a patient transport system that was developed to fit into an air ambulance. A validated decontamination procedure is required before the system can be adopted in the UK. Hydrogen peroxide (H2O2) vapour fumigation may offer better penetration of the inaccessible parts than the liquid disinfectant wiping that is currently suggested. To validate this, an EpiShuttle was fumigated in a sealed test chamber. Commercial bacterial spore indicators (BIs), alongside organic liquid suspensions and dried surface samples of MS2 bacteriophage (a safe virus surrogate), were placed in and around the EpiShuttle, for the purpose of evaluation. The complete kill of all of the BIs in the five test runs demonstrated the efficacy of the fumigation cycle. The log reduction of the MS2 that was dried on the coupons ranged from 2.66 to 4.50, but the log reduction of the MS2 that was in the organic liquids only ranged from 0.07 to 1.90, confirming the results of previous work. Fumigation with H2O2 alone may offer insufficient inactivation of viruses in liquid droplets, therefore a combination of fumigation and disinfectant surface wiping was proposed. Initial fumigation reducing contamination with minimal intervention allows disinfectant wipe cleaning to be completed more safely, with a second fumigation step inactivating the residual pathogens.

Effects of CoMo/γ-Al2O3 Catalysts on Product Hydrocarbon and Phenol Distribution during Hydrodeoxygenation of Oxidized Bio-Oil in a Batch Reactor

Hydrodeoxygenation is an essential process for producing liquid transportation fuels. In this study, the effects of CoMo/γ-Al2O3 catalysts form and loading ratio on the hydrodeoxygenation upgrading of bio-oil were investigated in a batch reactor. Raw bio-oil was first oxidized with hydrogen peroxides and oxone to obtain the oxidized bio-oil with reduced levels of aldehydes and ketones, increasing the organic liquid yield during hydrodeoxygenation by suppressing the coke formation. CoMo/γ-Al2O3 was selected as the catalyst because of its low cost and commercial availability. The effect of the reduction and sulfidation of CoMo/γ-Al2O3 catalyst on the hydrodeoxygenation of the oxidized bio-oil was compared. The effect of the catalyst loading ratio on bio-oil hydrodeoxygenation using sulfided CoMo/γ-Al2O3 catalysts was also investigated. The research results showed that the sulfided CoMo/γ-Al2O3 catalyst facilitated the formation of hydrocarbons, while the reduced CoMo/γ-Al2O3 catalyst produced more phenols in the organic liquids. Moreover, a high sulfided catalyst loading ratio promoted the formation of hydrocarbons.

The Formation Mechanism and Structure of Organic Liquids in the DFT Challenges

In the paper the experimental and theoretical approaches to problem of organic liquids formation mechanism and its structure are reviewed. It was shown that all presented models have the advantages and disadvantages at interpretation of molecular interaction and arrangement in liquid phase. The DFT calculation in different variant of models including paired interaction hydrogen atom transfer, model of transformation and the general conclusion following from this consideration are presented.

The Influence of Alkanethiols on the Production of Hydrophobic Gold Nanoparticles via Pulsed Laser Ablation in Liquids

The ability to suspend plasmonic metal nanoparticles in apolar environments is an important feat towards harnessing their optical properties for use in amphiphilic biological environments. Pulsed laser Ablation in Liquids (PLAL) is a well-established method for the production of gold nanoparticles (AuNPs) in aqueous environments; however, ablation in organic liquids for the synthesis of hydrophobic AuNPs still has many unknowns, such as the relationship between colloidal stability and the ligand shell. In this study, hydrophobic AuNPs were produced by PLAL of gold in a 1-alkanethiol/n-decane solution and treated with laser fragmentation. Results demonstrate that longer chain length ATs produced particles with a smaller average size; however, there was no strong correlation between alkanethiol (AT) concentration and particle size. Stability was investigated by monitoring the temporal evolution of the extinction spectra which revealed that lower concentrations of AT stabilize the colloids while higher concentrations tend to result in quicker particle aggregation. Furthermore, longer chain length ATs demonstrated improved stability. Additionally, vibrational spectroscopy was employed to examine the AuNP surface chemistry, which pointed to the presence of oxidized carbon species and graphitic carbon.

Two Faces of the Two Phase Thermodynamic Model

The quantum harmonic model and the two-phase thermodynamics method (2PT) are widely used to obtain quantum corrected properties such as isobaric heat capacities or molar entropies. 2PT heat capacities were calculated inconsistently in the literature. For water the classical heat capacity was also considered, but for organic liquids it was omitted. We reanalyzed the performance of different quantum corrections on the heat capacities of common organic solvents against experimental data. We have pointed out serious flaws in previous 2PT studies. The vibrational density of states was calculated incorrectly causing 39 % relative error in diffusion coefficients and 45 % error in the 2PT heat capacities. The wrong conversion of isobaric isochoric heat capacity also caused about 40 % error but in the other direction. We have introduced the concept of anharmonic correction (AC) which is simply the deviation of the classical heat capacity from that of the harmonic oscillator model. This anharmonic contribution is around +30-40 J/mol/K for water depending on the water model and -8-10 J/mol/K for hydrocarbons and halocarbons. AC is unrealistically large, +40 J/K/mol for alcohols and amines indicating some deficiency of the OPLS force field. The accuracy of the computations was also assessed with the determination of the self-diffusion coefficients.