In the present study, we investigate the regeneration efficiency of Rhodamine B (RhB)-saturated granular activated carbon (GAC) in an electrochemical regeneration system by using a ...9,10-anthraquinone-2-sulfonic acid/polypyrrole modified graphite plate (AQS/PPy-GP) cathode. The response surface methodology based on the Box-Behnken design (RSM-BBD) approach was used to optimize regeneration parameters, whereby the optimum condition of the independent variables was as follows: applied current = 155 mA, concentration of supporting electrolyte = 0.13 M, and regeneration time = 7 h. The electrochemical regeneration system with the AQS/PPy-GP electrode achieved high regeneration efficiency and significantly reduced energy consumption. H2O2 concentration generated in the electrolysis system was notably increased, and the time of complete degradation of organics was shortened by 25% compared to the electrode without modification. The mechanism for RhB degradation was proposed as AQS acting as a catalyst to promote the formation of H2O2. The regeneration study showed that AQS/PPy-GP cathode had appreciable reusability for GAC regeneration with a regeneration efficiency of 76.6% after 8 regeneration cycles. In summary, the electrochemical regeneration based on AQS/PPy-GP cathode would have practical industrial applications in treating spent activated carbons.
Display omitted
•A modified AQS/PPy-GP cathode was used in electrochemical regeneration of GAC.•Regeneration parameters were optimized by RSM-BBD method.•The modified AQS/PPy-GP cathode accelerated organics degradation and improved regeneration efficiency.•AQS/PPy-GP is economically efficient for its low energy consumption.
In this study, the low-cost and high-wear-resistant iron-based surfacing alloy powder is used to prepare composite coatings on the 2 mm thick Al7075 substrate with different volume ratios of Al6061 ...powder (3:4, 5:4 and 2:1) by the low pressure cold spray equipment. The thickness of composite coatings increases with the increasing in preheating temperature and is approximately 60-80 μm thick in single pass. The percentage of iron-based surfacing alloy powder increased with the decrease in the proportion of Al6061 powder. The microhardness and bonding strength of the coatings increase with the increase in the percentage of surfacing alloy powder due to the tamping and work-hardening effect. The wear mechanism of cold sprayed composite coatings involves both abrasive and adhesive wear on the worn surface under different loads. The wear mechanism of the micro-arc oxidation sample transforms via abrasive wear to abrasive and adhesive wear as the load changes from 5 to 10 N. Investigation about wear properties reveals that the micro-arc sample has better wear resistance at the load of 5 N, but the cold sprayed composite coatings have better wear resistance at 10 N. The Al
2
O
3
layer is worn out and the substrate is exposed during sliding for micro-arc oxidation samples at the higher load. The results indicate that the low pressure cold spraying may replace the micro-arc oxidation technique under the higher load condition in industrial applications.
Abstract In recent years, as an emerging dynamic bonding, silyl ether linkages have been concerned and applied. However, the reprocessability of vitrimers based on it is far from satisfactory because ...of the inactive dynamic exchange reaction. At the same time, the mechanical properties of polysiloxane elastomers are poor because of the high flexibility of polysiloxane molecular chains and weak intermolecular forces. Herein, we have successfully synthesized a PDMS elastomer incorporating Zn(II)‐amine coordination bonds as sacrificial units, which are crosslinked through dynamic silyl ether linkages. Importantly, the presence of Zn ions promotes the exchange between the silyl ether linkages and hydroxyl groups. The elastomers exhibited excellent mechanical properties (35 times improvement in toughness) and outstanding reprocessability. The mechanical property recovery of the PDMS elastomers reached approximately 90% after four reprocessing cycles. Meanwhile, small‐molecule simulation experiments were conducted to verify the significant catalytic effect of Zn (II) ions as Lewis acid catalysts on the exchange reaction of silyl ether linkages and hydroxyl groups. In a word, this work provides a facile strategy to simultaneously enhance the mechanical properties and reprocessing performance of silyl ether‐linked polysiloxane elastomers.
Abstract Environmentally friendly high‐performance composites made from either reprocessable polymer matrix or renewable fillers have become increasingly significant in order to reach a sustainable ...future. Herein, polydimethylsiloxane/modified cellulose nanocrystals (PDMS/mCNC) composites showing outstanding mechanical and reprocessable properties via silyl ether linkages are prepared. With only 1 wt% mCNC, the PDMS/mCNC composite exhibits the tensile strength of 2.96 MPa, which is twice that of the pure PDMS elastomer, while the toughness can achieve 7.32 MJ m − 3 . Remarkably, the reprocessing efficiency can be as high as 100% even for triple reprocessing process. Additionally, the favorable effect of mCNC on constructing hybrid filler network within vitrimers is explored for the first time. Selection of boron nitride nanosheet (BNNS) as the functional filler, 40 wt% BNNS is uniformly dispersed by only a small amount of mCNC and a homogeneous thermally conductive network is built, with the thermal conductivity of the PDMS/mCNC@BNNS composite increasing remarkably to 2.901 W m −1 K −1 . In a word, this work paves the way to develop sustainable, mechanically strong, and reprocessable composites with mCNC as a renewable bio‐filler.
In this study, a multi-particle Eulerian model with finer meshing size was established by Python script in order to investigate the deposition process of metallic and MG coatings during cold ...spraying. The simulation results showed that the penetration depth of the substrate has connect with the strain hardening exponent and the pores existed at the particle boundaries shrunk as the preheating temperature rose. The qualitatively analysis about residual stress for the Cu/Cu combination at the interface between the coating and substrate was tensile, which was consistent with the previous study. For the MG coatings, particles experienced inhomogeneous deformation and attached loosely at lower preheating temperatures. But homogeneous deformation emerged at higher preheating temperatures and the coatings became dense. Hard substrates were preferred when preparing MG coatings. Differences between the metallic coatings and MG coatings during the coating formation were mainly attributed to four aspects: the purpose of preheating, the deformation mechanism, the determination of spraying parameters and the selection of substrates.
•Prevalence of low-grade inflammation among bipolar disorder in Han Chinese population is about 10 %.•Low-grade inflammation of different definition impacts differentially on the clinical features of ...bipolar disorder.•Low-grade inflammation (C-reactive protein levels>3 mg/L) is associated with recent suicide attempt and family history of mental disorders.•Low-grade inflammation (white cell count > 9.5 × 109/L) is related with psychotic features and previous adverse life events.
Variety of evidence suggests that low-grade inflammation may be involved in the pathophysiology of bipolar disorder (BD). However, the conclusion regarding the relationship between inflammation and BD has been inconsistent. In this study, we aimed to survey the prevalence of low-grade inflammation in a large Han Chinese population with BD and assess its impact on the clinical features of BD.
430 eligible cases were drawn from patients who were admitted or had ever been admitted for BD to the inpatient service of the psychiatric department of the Third Hospital of Sun Yat-sen University. Subjects with current active physical diseases or white blood count (WBC) >19.0 × 109/L (2 times the upper reference) were excluded. Serum C-reactive protein (CRP) levels and WBC were measured with fast blood sample. Low-grade inflammation was defined as CRP>3 mg/L or WBC > 9.5 × 109/L(the upper reference). Clinical features of BD were collected through semi-structural interview conducted by trained interviewers with background of psychiatric education.
If defined as CRP>3 mg/L, the prevalence of low-grade inflammation among BD was 10.1% (41/404), it was positively associated with BMI (p = 0.012), comorbidity of glycolipid metabolic diseases(p = 0.018). After adjusting for BMI, it was found to be positively related to recent suicide attempt (p = 0.03), initiation with (hypo)manic episode(p = 0.047), leaden paralysis (p = 0.037) and family history of mental disorders(p = 0.012), while the association between comorbidity of glycolipid metabolic diseases and low-grade inflammation disappeared (p = 0.330). If defined as WBC > 9.5 × 109/L, the prevalence of low-grade inflammation was 8.1% (33/409), it was positively associated with psychotic features (p = 0.011) and adverse life events before the onset of illness(p < 0.001), but was not significantly influenced by BMI (p = 0.077).
A much lower prevalence of low-grade inflammation in BD is found among Han Chinese population than among western population. Low-grade inflammation of different definition impacts differentially on the clinical features of BD.
In recent years, as an emerging dynamic bonding, silyl ether linkages have been concerned and applied. However, the reprocessability of vitrimers based on it is far from satisfactory because of the ...inactive dynamic exchange reaction. At the same time, the mechanical properties of polysiloxane elastomers are poor because of the high flexibility of polysiloxane molecular chains and weak intermolecular forces. Herein, we have successfully synthesized a PDMS elastomer incorporating Zn(II)‐amine coordination bonds as sacrificial units, which are crosslinked through dynamic silyl ether linkages. Importantly, the presence of Zn ions promotes the exchange between the silyl ether linkages and hydroxyl groups. The elastomers exhibited excellent mechanical properties (35 times improvement in toughness) and outstanding reprocessability. The mechanical property recovery of the PDMS elastomers reached approximately 90% after four reprocessing cycles. Meanwhile, small‐molecule simulation experiments were conducted to verify the significant catalytic effect of Zn (II) ions as Lewis acid catalysts on the exchange reaction of silyl ether linkages and hydroxyl groups. In a word, this work provides a facile strategy to simultaneously enhance the mechanical properties and reprocessing performance of silyl ether‐linked polysiloxane elastomers.
Three types of aluminum alloy powder were mixed with the Al-based metallic glasses powder in different proportions, and the Al-based metallic glasses composites were prepared by cold spraying. The ...microstructure of the coatings was investigated, and the compressive strength of the Al-based metallic glasses composites was tested. Numerical simulation was carried out to study the formation of the composite coatings. The porosity of the composite coatings was significantly lower than for the Al-based metallic glasses coating. The maximum compression strength was 584 MPa when adding 50% Al7075 powder, and the compressive strength of Al-based metallic glasses composites has a positive correlation with the types of added aluminum alloy powder. The grinding effect due to the relative slip between the Al-based metallic glasses particles and the soft particles was observed at the fracture surface. The Al-based metallic glasses particles were packed closely with the surrounding Al7075 particles after fracture. Simulation results showed that the soft particles behaved like a droplet when impacted onto the metallic glasses particles, and gaps between the metallic glasses particles were filled with soft particles, but some pores still existed when adding Al7075 powder due to its relatively higher strength.
PDF