The effect of the initial salt concentration on the rate of crystallization in a thin layer of solution

Adsorption is a key technology for heavy metals removal from industrial effluents. The use of adsorbent polymers is considered to be an attractive solution for wastewater treatment due to their high selectivity for certain heavy metals. Through the current study, an adsorptive polyacrylonitrile based hydrogel blend was used to examine heavy metals removal in simulated effluents incorporating chromium and nickel. Moreover, Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) in conjunction to an Energy Dispersive X-Ray Spectroscopy (EDX) were used for characterization of the polymeric blend structure. Finally, for surface evaluation, the specific surface area and the pore size distribution Brunauer-Emmett-Teller (BET) analysis techniques were used together with electrical conductivity measurements. The obtained results from FTIR showed the appearance of the original bands of raw materials (polyacrylonitrile (PAN), polyvinyl alcohol and polyaniline (PAni) and the change of the peaks position confirmed the hydrolysis and combination of starting materials into the polymeric blend. Surface morphology studies showed that this gel has porous surface with an average pore size and surface area of 0.73 nm and 17.3 m2 /g, respectively. Moreover, Electrical conductivity measurements indicated the presence of PAni in the polymeric blend assisted in the increase in conductivity of PAN. Finally, the different parameters of the polymeric hydrogel blend were investigated through swelling water ratio (SWR) and conventional adsorption processes at different operating conditions such as; initial salt concentration, pH and contact time. The maximum chromium adsorption results were (12.44 mg/g for 10 mg/L initial salt concentration), (10.46 mg/g for 5.5 pH) and (4.91 mg/g for 1 hr. contact time). Whereas, the maximum nickel adsorption was (7.67 mg/g for 20 mg/L initial salt concentration), (7.57 mg/g for 7 pH) and (6 mg/g for 2 hrs. contact time).

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Recycling Lithium from Waste Lithium Bromide to Produce Lithium Hydroxide

Membranes ◽

10.3390/membranes11100759 ◽

2021 ◽

Vol 11 (10) ◽

pp. 759

Author(s):

Wenjie Gao ◽

Xinlai Wei ◽

Jun Chen ◽

Jie Jin ◽

Ke Wu ◽

...

Keyword(s):

Current Density ◽

Salt Concentration ◽

Hydrobromic Acid ◽

Lithium Bromide ◽

High Energy ◽

Lithium Hydroxide ◽

Efficient Production ◽

High Current ◽

Chamber Volume ◽

Initial Salt

Lithium resources face risks of shortages owing to the rapid development of the lithium industry. This makes the efficient production and recycling of lithium an issue that should be addressed immediately. Lithium bromide is widely used as a water-absorbent material, a humidity regulator, and an absorption refrigerant in the industry. However, there are few studies on the recovery of lithium from lithium bromide after disposal. In this paper, a bipolar membrane electrodialysis (BMED) process is proposed to convert waste lithium bromide into lithium hydroxide, with the generation of valuable hydrobromic acid as a by-product. The effects of the current density, the feed salt concentration, and the initial salt chamber volume on the performance of the BMED process were studied. When the reaction conditions were optimized, it was concluded that an initial salt chamber volume of 200 mL and a salt concentration of 0.3 mol/L provided the maximum benefit. A high current density leads to high energy consumption but with high current efficiency; therefore, the optimum current density was identified as 30 mA/cm2. Under the optimized conditions, the total economic cost of the BMED process was calculated as 2.243 USD·kg−1LiOH. As well as solving the problem of recycling waste lithium bromide, the process also represents a novel production methodology for lithium hydroxide. Given the prices of lithium hydroxide and hydrobromic acid, the process is both environmentally friendly and economical.

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Effect of Complex Food Environment on Production of Enteriocin IN 3531 with Enterococcus faecium IN3531 as a Starter in Chinese Fermentation Paocai Making

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.884-885.429 ◽

2014 ◽

Vol 884-885 ◽

pp. 429-432 ◽

Cited By ~ 5

Author(s):

Wen Li Liu ◽

Lan Wei Zhang ◽

John Shi ◽

Hua Xi Yi

Keyword(s):

Salt Concentration ◽

Food Environment ◽

Enterococcus Faecium ◽

Inoculum Size ◽

Fermentation Temperature ◽

Initial Salt

Enterococcus faeciumIN3531 has beensuccessfully confirmed to have no disease-causing factors and antibioticresistance and it had been confirmed that the ability to produce bacteiocins inMRS. In this study, the effects of the complex food environment in Chinese fermentationpaocai making on Enteriocin IN3531 production were studied. It was concludedthat the complex food environment didn’t thoroughly interferes with bacteriocinproduction levels. Results obtained showed that the suitable fermentationconditions for enterocin IN3531 production in Chinese fermentation paocai makingusingEnterococcus faeciumIN3531 asa starter were the initial salt concentration of 2%, the inoculum size of 3%,the fermentation temperature of 35 °C, the ratio of material to liquid of 30%, fermentationtime of 108 hours.

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FFD Analysis for the Effect of Fouling on the Permeate Flux in High-Pressure Membranes

European Journal of Engineering Research and Science ◽

10.24018/ejers.2019.4.1.1061 ◽

2019 ◽

Vol 4 (1) ◽

pp. 12-16

Author(s):

Hisham A. Maddah

Keyword(s):

High Pressure ◽

Salt Concentration ◽

Membrane Fouling ◽

Concentration Polarization ◽

Water Flux ◽

Side Surface ◽

Permeate Flux ◽

Salt Accumulation ◽

Initial Salt ◽

Negative Flux

Porous high-pressure membranes have been widely used for both brackish water and seawater desalination. However, fouling (concentration polarization) extensively reduces permeate flux in high-pressure membranes such that reverse osmosis (RO) and/or nanofiltration (NF). In this study, we have attempted to understand the effect of membrane fouling on the permeate water flux by modeling the salt concentration profile within a membrane of interest. A parabolic (or diffusion) partial differential equation was used to describe the change in salt concentration inside the membrane. Subsequently, the PDE equation was solved numerically, under certain assumptions, by using forward finite difference (FFD) explicit method. It was found that salt accumulation occurs at the membrane feed-side surface and there was a noticeable decrease in water flux as fouling increased. For waters with an initial salt concentration of 10000 ppm (NaCl) and with an average diffusivity of , results showed that both RO/NF would have flux rates of 74.9, 67.4, 22.5, 0, –37.4, –74.9 LMH for the feed-side surface concentrations 0, 1000, 7000, 10000, 15000 and 20000 ppm, respectively, where negative flux indicates a back-flow scenario.

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Applications of Photoelectron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092499 ◽

1976 ◽

Vol 34 ◽

pp. 506-507

Author(s):

William J. Baxter

Keyword(s):

Electron Microscopy ◽

Thermal Decomposition ◽

Chemical Composition ◽

Ultraviolet Radiation ◽

Thin Layer ◽

Edge Effects ◽

Electron Optics ◽

Surface Layers ◽

Crystalline Orientation ◽

Fluorescent Screen

In this form of electron microscopy, photoelectrons emitted from a metal by ultraviolet radiation are accelerated and imaged onto a fluorescent screen by conventional electron optics. image contrast is determined by spatial variations in the intensity of the photoemission. The dominant source of contrast is due to changes in the photoelectric work function, between surfaces of different crystalline orientation, or different chemical composition. Topographical variations produce a relatively weak contrast due to shadowing and edge effects.Since the photoelectrons originate from the surface layers (e.g. ∼5-10 nm for metals), photoelectron microscopy is surface sensitive. Thus to see the microstructure of a metal the thin layer (∼3 nm) of surface oxide must be removed, either by ion bombardment or by thermal decomposition in the vacuum of the microscope.

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