The difference lies in the type of state they are in. When M is mentioned it means it refers to a solution while mol refers to pure substance. Thus, 0. Other Related Questions on Physical Chemistry. View all Questions ». You will get reply from our expert in sometime. We will notify you when Our expert answers your question. To View your Question Click Here. Analytical Chemistry Video Lessons. Cell Biology Video Lessons.
Genetics Video Lessons. Biochemistry Video Lessons. GOB Video Lessons. Microbiology Video Lessons. Calculus Video Lessons. Statistics Video Lessons. The pH of the demineralizing solution was about 4. The pH of the remineralizing solution was about 7 and it contained 1. At the end of each day, the solutions were changed and all specimens were washed with distilled water before placing them in fresh solution.
After the erosion process, the abrasion test was performed with a mechanical tooth brushing machine Dersa Brushing Device Company, Karaj, Iran. The device had 8 spots for the placement of toothbrush and specimens. The toothbrush had a horizontal back-and-forth movement. The surface roughness and weight of the specimens were measured as explained for the baseline measurements.
Weight loss of the specimens which was equivalent to the total amount of abrasion, attrition, and erosion wear of the composites was separately recorded for each specimen. Table 2 presents the descriptive results. One-way ANOVA showed a significant difference in the mean weight change of specimens before and after attrition, abrasion, and erosion tests.
But the surface roughness changes were not significant between the composite resins , Table 3. EverX and Filtek Bulk-Fill composites did not have a statistically significant difference , and SonicFill 2 did not have a significant difference with other tested composites in terms of weight loss.
The present study assessed the weight and surface roughness changes of several bulk-fill composites Filtek Bulk-Fill, EverX Posterior, SonicFill 2, and X-tra fil in comparison with a conventional composite Filtek Z after abrasion, attrition, and erosion tests.
In this study, a chewing simulator was used for the attrition test, pH cycling was performed to simulate erosion, and a tooth brushing device was used for abrasion simulation.
The results obtained from the surface roughness test after abrasion, attrition, and erosion tests in this study showed that although the surface roughness of specimens decreased, this reduction was not significant compared with the baseline value. The surface roughness results after wear in the present study were inconsistent with the results of several previous studies. Han et al. Also, the difference in the increase in surface roughness after abrasion can be related to the difference in the size of filler particles in different composites.
In nanocomposites, the filler and the matrix are worn away simultaneously. Therefore, the increase in surface roughness following wear is lower. It appears that the difference in surface roughness after abrasion is due to the fact that in these studies, the specimens were only brushed and were not subjected to erosion and attrition.
An effective factor in increasing the surface roughness following erosion and abrasion is the water sorption by the matrix, which increases the osmotic pressure at the interface of the organic matrix and the mineral fillers and causes cracks in the surface as well as hydrolytic degradation of silane and subsequent filler separation from the surface.
The reason for the increase in brushing roughness after erosion is that the fillers exposed by erosion are separated from the surface under shear forces and leave small holes on the surface, which increase the surface roughness [ 23 ]. Turssi et al. The reason was the destruction of the matrix and formation of cavities on the composite surface due to the degradation of the resin matrix and silane as a result of acid attacks.
X-tra fil composite showed higher surface roughness than the acceptable threshold in the present study. The results of the present study revealed that the weight loss after wear in bulk-fill composites was not significantly different from that in the conventional composite, which is consistent with the results of Engelhardt et al. They assessed the abrasion resistance of a bulk-fill flowable composite and a conventional flowable composite and showed no difference between them in terms of abrasion resistance.
This finding can be due to the fact that wear resistance is a material-dependent property that varies between different composites depending on the type of matrix and filler properties, and it is not related to the bulk-fill or conventional nature of composites [ 3 ]. However, Elmamooz et al. Contrary to the results of the present study, they showed that the surface roughness of bulk-fill composite was higher than that of conventional composite after brushing, and the highest surface roughness was related to Tetric N Ceram Bulk-Fill and X-tra fil.
The greatest weight loss was recorded for Tetric N Ceram Bulk-Fill, which was due to the larger size of filler particles in this bulk-fill composite compared with Grandio conventional composite. They also mentioned that greater surface roughness after brushing of the bulk-fill composite was responsible for more material loss in this process [ 25 ]. The results of the present study showed that the rate of weight loss after wear in X-tra fil composite was significantly greater than that in EverX Posterior composite and Filtek Bulk-Fill composite.
One reason may be the higher surface roughness of X-tra fil following wear, which makes it easier to remove the exposed fillers in two and three-body wears and is followed by a greater weight loss in this composite [ 12 , 15 , 26 ]. Shimokawa et al. They concluded that there was no correlation between the filler content and wear rate because the filler content of Admira Fusion x-tra was higher than that of Filtek Bulk-Fill.
Higher wear rate of Admira Fusion x-tra was attributed to its higher rate of surface roughness after wear, which causes greater loss of material mass from the rough surface during wear.
Factors such as the silanization quality of the matrix and the irregular size and shape of filler particles contribute to higher wear of this composite. However, Wang et al. High filler percentage of X-tra fil composite can be associated with higher wear. Hu et al. Increasing the coefficient of friction between the filler and matrix particles and the weak bond between the filler and the matrix can cause mass loss from the surface of samples with high filler content, which leads to higher surface roughness in them.
However, Han et al. This monomer decreases the viscosity of the resin matrix and has higher water sorption and susceptibility to hydrolysis compared with bis-GMA and bis-EMA monomers and increases the wear and surface roughness of materials.
TEGDMA is also present in the composition of Z composite, but the different percentage of this monomer in the two composites can be the reason for the difference in the results [ 20 ]. Filler shape is another factor that affects the wear rate. It has been shown that composites with round submicron fillers have high abrasion resistance [ 28 ]. Filler size, volume, distribution and chemical properties, resin matrix properties, and photoinitiator are among other influential factors on the wear rate [ 8 , 14 ].
The glass transition temperature, at which the material changes from rigid to rubber state, affects the degree of curing of composite and subsequently its wear rate as well. There is also a correlation between the Vickers hardness number and wear rate [ 3 ]. The weight loss in these two composites was significantly different from that in X-tra fil. For example, a significant improvement in the selectivity and recovery rate in the unit operation is required to be able to be competitive as compared to other state-of-the-art techniques Supplementary Table 1.
Further in-depth systematic parametrization studies are currently underway to improve selectivity and recovery rate by uniform coating of PDADMA polymer and rational design of electrochemical interfaces and electrochemical cells.
In summary, we have successfully shown that speciation control through electrolyte engineering, combined with surface functionalization by using charged polymers, enabled the synergistic tuning of metal selectivity during electrochemical deposition. The use of concentrated chloride imparted opposite charges to cobalt and nickel, and thus discriminated between metals with otherwise similar reduction potentials and ionic characteristics, allowing for potential-dependent selectivity by leveraging anomalous deposition—with the electrolyte being able to be recycled.
We applied our proposed process for the direct recovery of cobalt and nickel from practical spent NMC cathodes, demonstrating that high-purity metal recovery can be achieved solely by electrochemical pathways. We envision that the recovered cobalt and nickel can be possibly revalorized as value-added precursors for the fabrication of fresh cathode materials. In the future, we expect our findings on electrodeposition at functional surfaces to not only enable selectivity for precision metal separations, but also offer pathways for materials processing through morphology control and patterning.
To highlight the synergistic contributions of speciation control and interfacial tailoring on selectivity, we initially explored solely the effect of electrolyte by using a copper foil as a cheap and conductive substrate without the use of the polymer coating.
Next, we investigated how the combined use of controlled electrolyte and polymer interfaces overcomes the limitations of conventional electrodeposition, and offers selectivity tunability. Copper foil was employed as a working electrode for cobalt and nickel deposition; the electrodes were prepared by cutting the copper foil thickness 0. The effective working area of cobalt and nickel deposition, immersed in the electrolyte, was 0.
A platinum wire length: 7. In the LSV test, the onset potential of electrodeposition was defined as the intersection of tangential lines of the horizontal background current non-faradaic zone and the faradaic zone in the initial current increase.
Each sample was measured with at least 15 replicates by the spectrometer to yield a reliable averaged reading. From the ICP measurements, faradaic efficiencies of metal electrodeposition were determined by:. Considering that two electrons are involved either in direct deposition Eq. Also, the amount of remaining cobalt and nickel on the electrodeposit after the stripping was determined by digesting the deposit and quantifying the metals using ICP-OES, as described above. Finally, stripping efficiencies were determined by:.
The mass increase was determined using the Sauerbrey equation 27 :. The following pretreatment steps were conducted before the electrochemical recovery was carried out:. The remaining cell voltage was frequently monitored using a portable multimeter and full discharge was confirmed before manual disassembly.
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Adsorption 25 , —
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