Coupled Effects of Aging and Weak Magnetic Fields on Sequestration of Selenite by Zero-Valent Iron

The sequestration of Se­(IV) by zero-valent iron (ZVI) is strongly influenced by the coupled effects of aging ZVI and the presence of a weak magnetic field (WMF). ZVI aged at pH 6.0 with MES as buffer between 6 and 60 h gave nearly constant rates of Se­(IV) removal with WMF but with rate constants that are 10- to 100-fold greater than without. XANES analysis showed that applying WMF changes the mechanism of Se­(IV) removal by ZVI aged for 6–60 h from adsorption followed by reduction to direct reduction. The strong correlation between Se­(IV) removal and Fe²⁺ release suggests direct reduction of Se­(IV) to Se(0) by Fe⁰, in agreement with the XANES analysis. The numerical simulation of ZVI magnetization revealed that the WMF influence on Se­(IV) sequestration is associated mainly with the ferromagnetism of ZVI and the paramagnetism of Fe²⁺. In the presence of the WMF, the Lorentz force gives rise to convection in the solution, which narrows the diffusion layer, and the field gradient force, which tends to move paramagnetic ions (esp. Fe²⁺) along the higher field gradient at the ZVI particle surface, thereby inducing nonuniform depassivation and eventually localized corrosion of the ZVI surface

Mussel-Inspired Chemical Modification of Cotton Fabrics for Oil/Water Separation

A hydrophobic and lipophilic cotton fabric based on mussel-inspired chemistry was developed to improve surface durability. The surface morphology and wettability of the modified fabrics were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric/differential thermal analysis, and contact angle measurement. The water contact angle and surface wettability analysis showed that the modified cotton fabric had a water contact angle of 154.9°, and the modified cotton fabric could be driven by gravity to separate the mixture of oil and water and had good separation efficiency for different types of oil and water mixtures, which was equal to or greater than 97% on average. In addition, the oil/water separation flux could be controlled by adjusting the pore size of the modified fabric

Advances in Sulfidation of Zerovalent Iron for Water Decontamination

Sulfidation has gained increasing interest in recent years for improving the sequestration of contaminants by zerovalent iron (ZVI). In view of the bright prospects of the sulfidated ZVI (S-ZVI), this review comprehensively summarized the latest developments in sulfidation of ZVI, particularly that of nanoscale ZVI (S-nZVI). The milestones in development of S-ZVI technology including its background, enlightenment, synthesis, characterization, water remediation and treatment, etc., are summarized. Under most circumstances, sulfidation can enhance the sequestration of various organic compounds and metal­(loid)­s by ZVI to various extents. In particular, the reactivity of S-ZVI toward contaminants is strongly dependent on S/Fe molar ratio, sulfidation method, and solution chemistry. Additionally, sulfidation can improve the selectivity of ZVI toward targeted contaminant over water under anaerobic conditions. The mechanisms of sulfidation-induced improvement in contaminants sequestration by ZVI are also summarized. Finally, this review identifies the current knowledge gaps and future research needs of S-ZVI for environmental application

Ordinal logistic regression results for discharge AIS (number of observations = 489).

<p>R-Square = 0.6637,Max-rescaled R-Square = 0.7156.</p><p>Dependent variable: AIS at Discharge (A, B, C, D, E).</p><p>Independent variables: AIS at Admission (A, B, C, D), Neurological Level (High, Medium, Low), Rehabilitation (Yes, No) AIS: American Spinal Injury Association (ASIA) Impairment Scale DF: degrees of freedom.</p><p>The Wald Chi-Square test is used to test the statistical significance of parameters in the logistic regression models.</p

Summary of the variables estimated and the methodology involved in creating the simulation model.

<p>All variables are significant (p-value<0.05). ✓Indicates the independent variable(s) that can estimate the dependent variable (e.g. the dependent variable AIS can be estimated by the independent variables age and energy); MOI: Mechanism of Injury; Neuro Level: Neurological Level of Injury; ISS: Injury Severity Score; GCS: Glasgow Coma Scale; AIS: ASIA Impairment Scale; SCU: Special Care Unit; VGH: Vancouver General Hospital; LOS: Length of Stay; ED: Emergency Department; OR: Operating Room; Rehab: Rehabilitation; FIM: Functional Independence Measure.</p

Scenario One: Indirect impact of pressure ulcer reduction during acute care.

<p>Reducing pressure ulcers during acute care has direct impacts on overall complications and length of stay in acute care, but also indirect impacts on rehabilitation complications, length of stay and bed utilization.</p

Scenario Two: Indirect impacts of early surgery.

<p>Providing early surgery to patients with tetraplegia has a direct impact on their neurological recovery and also indirect impact on their life expectancy, quality of life and savings in their rest of life costs.</p

Flow chart of the study design.

<p>Starting with initial information acquisition, followed by process mapping (level 1 and 2), data collection & analyses, model development & validation and “what-if” scenario analyses.</p

Scenario Three: The indirect impact of additional rehabilitation beds.

<p>Adding rehabilitation beds has an impact on the admission to rehabilitation waiting time (alternative level of care days in acute), acute length of stay, bed utilization at the rehabilitation centre and rehabilitation length of stay. ALC: Alternative Level of Care Days; LOS: Length of Stay; Rehab: Rehabilitation.</p