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Montmorillonite-based porous adsorbent prepared by gel casting method was used to adsorb Cr(III)-organic complexes in tanning wastewater,together with the initial concentration of 10 mg L−1. The as-porous adsorbent exhibited an excellent performance of separation. Meanwhile, its structural and morphology were characterized by TG, BET, XRD, SEM, EDS and XPS, showing that the porous adsorbent was complete hollow ball structure. And the adsorption results showed that the adsorption amount of porous adsorbent rapidly declined from 9.58 to 5.28 mg L−1, and only Cr(III) was adsorbed, when the molar ratio of Cr(III) and citrate was more than 1:5. Increased of pH was beneficial to adsorb Cr(III)-citrate in range from 2.46 to 7.12. Furthermore, the best removal efficiency of Cr(III)-organic complex was up to 97% and still above 84% after five cycles with porous adsorbent. Finally, the mechanism on adsorbing Cr(III) with porous adsorbent is also provided. Therefore, a kind of porous adsorbent which was easily separated, was prepared to deeply treat tanning wastewater containing Cr(III)-organic complex, and solve the problem of difficult recycle.

Zirconium dioxide loaded montmorillonite (ZrO 2 -MMT) composites have been prepared using an ion-exchange process at room temperature followed by a thermal treatment. The as-prepared composites are used to adsorb Cr 3+ ions in the tanning wastewater with a lower initial Cr 3+ concentration, reducing residual Cr 3+ concentration to less than 1 mg L −1 . XRD, TEM, SEM-EDS and XPS analyses are made to explore the structure and morphology of the composites. ZrO 2 is found to load on the interlayer and surface of MMT. The adsorption process is appropriately described by the pseudo-second-order kinetic equation and Langmuir equation. The ZrO 2 -MMT composites exhibit a better adsorption capacity than adsorption materials reported in the literature, and the maximum adsorption capacity for the initial Cr 3+ concentration of 10, 20, 30 mg L −1 is as large as 142.86, 158.73 and 172.41 mg g −1 , respectively. The removal efficiency of ZrO 2 -MMT for Cr 3+ remains above 92% after six cycles.

A novel PTH-derived peptide, PTHdP, including a repetitive aspartic acid sequence at the C-terminal and phosphorylated serine at the N-terminal has been previously designed. To evaluate its potential as a bone growth factor for bone tissue engineering, true bone ceramics incorporated with nanohydroxyapatite coating and chitosan (CH/TBC) was developed as a desired three-dimensional porous delivery carrier in this study. In vitro results showed that PTHdP could be loaded with high-efficiency and subsequently released in a controlled and sustained manner from CH/TBC. Bioactivity of released PTHdP was retained and able to exert a significant effect on promoting or inhibiting osteogenesis actions when exposed intermittently or continuously, respectively, for MC3T3-E1 cell culture. As evaluated in a critical-size rabbit radial defect model by radiographic and histological examination, the combination of CH/TBC scaffolds with PTHdP exhibited a remarkably stronger capacity to stimulate new bone formation than control and pure CH/TBC groups. These results indicated the novel PTHdP peptide achieved high affinity to bone mineral without interference in bioactivity, and local delivery of PTHdP from apatite materials could be a promising alternative for future bone tissue engineering.

Titanium dioxide/graphene (TiO2/G) was synthesized by a simple method through adding cationic surfactant to assist the stabilization of rutile TiO2 in aqueous solutions and facilitate the electrostatic assembly of binding with surface of graphene. TiO2/G materials were used for investigation of its conductivity and dispersibility. The TiO2/G was showed significantly to enhance in conductivity and dispersibility after adding cetyltrimethylammonium bromide (CTAB). The good performance may be attributed to increasing TiO2 to uniformly distribute on the surface of graphene in the presence of CTAB. The TiO2/G composite was characterized by Zeta potential, Fourier transformed infrared spectra (IR), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Electrochemical impedance spectroscopy (EIS), respectively. The CTAB does not affect the crystalline structure of TiO2 and graphene. When CTAB is 30%wt of TiO2 and graphene is 7%wt of TiO2 that the resistivity of TiO2/G is measured as 2.4 Ω cm. The dispersion of TiO2/G can be kept for 24 h without precipitation. EIS showed that the TiO2/G with 30%wt of CTAB had the lowest electrical resistance, which tended to be consistent with the results of the measured resistivity. The results showed that the best conductivity and dispersibility of the TiO2/G composite with CTAB in this experiment.

Recovering Cr(III) from chromium-containing waste (CCW) is considered to be a friendly way to protect environment. In this paper, the recovery of Cr(III) from CCW is achieved, via alkali incineration (NaOH and Na2CO3), followed with leaching process using HCl. Firstly, it is demonstrated that there is a large amount of organic matters (oxygen-containing functional groups contained in collagen) in CCW, charactering with Infrared spectrophotometry (FT-IR), Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Furthermore, density functional theory (DFT) simulation method is carried out to study the inhibitory behavior of organic matters on recovery of Cr(III). Through geometric optimization, binding energy calculation and a series of electronic structure analysis, the influence of organic matters are analyzed in detail. According to the calculation results, it is clarified that the inhibition mechanism of organic matters on Cr(III) is mainly contributing by forming covalent bond and -OH exhibits greater inhibiting effect than -COOH. In this examine, the related factors are also investigated to reduce the amount of organic matters that is destroyed, including extractant species, alkali dosage, acid dosage and acid concentrations. Finally, the recovering efficiency of Cr(III) is greatly enhanced (95.83%), associated with optimized factors in the process.

Chromium (Cr) has become one of the main pollutants in tannery wastewater, which causes great harm to human health and environment, especially after being oxidized. Herein, the magnetic graphene oxide composite (GO/Fe3O4) is synthesized via coprecipitation method with NH3·H2O. In this way, the self-functional group of graphene oxide (GO) are greatly reserved when Fe3O4 nanoparticles grown on GO sheets, confirming by characterizations, including Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and Raman. Up to 90% Cr3+ could be adsorbed by resulted GO/Fe3O4 within 140 min, and the maximum adsorption capacity is 279.62 mg g-1. Furthermore, Cr3+ is mainly absorbed by chemical adsorption, according with quasi-second-order kinetic model and Langmuir isotherm. Most importantly, the external magnetic field can effectively recycle the adsorbents from the aqueous solution, facilitating its application in large-scale treatment of tannery wastewater.

In this work, we introduced TiH 2 into the 17MgH 2 -12Al composite by ball milling for improving the dehydrogenation performance of the reactive system. According to the measurements of non-isothermal dehydrogenation, the onset temperature of hydrogen release from 17MgH 2 -12Al-TiH 2 was reduced by 50 °C from that of 17MgH 2 -12Al. The investigations by Kissinger's method showed that the activation energy of hydrogen desorption of 17MgH 2 -12Al-TiH 2 (107 kJ mol −1 ) is much lower than 17MgH 2 -12Al (168 kJ mol −1 ), leading to enhanced dehydrogenation kinetics due to the TiH 2 additive. X-ray diffraction (XRD) analysis suggests that TiH 2 catalyzed the reaction between MgH 2 with Al of the system during the dehydrogenation below 280 °C. At temperatures between 280 °C to 400 °C, however, TiH 2 will thoroughly react with produced Mg 17 Al 12 and liberate hydrogen. The overall reaction of the system may be represented by 17 MgH 2 + 12 Al + TiH 2 → 3/4 Mg 17 Al 12 + Al 3 Ti + 17/4 Mg + 18 H 2 . Its theoretical dehydrogenation capacity (4.38 wt% H 2 ) agrees well with that achieved by temperature programmed dehydrogenation (TPD) measurements, demonstrating the occurrence of such reaction(s). The dehydrogenation enthalpy of 17MgH 2 -12Al-TiH 2 (71.7 kJ mol −1 H 2 ) proceeding at lower hydrogen desorption plateau was significantly lowered from that of 17MgH 2 -12Al (81.9 kJ mol −1 H 2 ) according to the measurements of pressure-composition isotherms (PCI) and van't Hoff plots. It means that TiH 2 was involved in the end reaction proceeding in the 17MgH 2 -12Al system. We believe that TiH 2 improves the dehydrogenation kinetics of 17MgH 2 -12Al initially and tailors its thermodynamics finally.

TiH2 was introduced into the 4MgH2-NaAlH4 composite by ball milling to improve the dehydrogenation and re-dehydrogenation performance of the composite. The non-isothermal dehydrogenation curve shows that the onset temperature of hydrogen release from 4MgH2-NaAlH4-TiH2 is at around 100 °C, which is lower by 50 °C than that of 4MgH2-NaAlH4. The investigation by Kissinger's method indicates that 4MgH2-NaAlH4-TiH2 possesses much lower activation energy (68 kJ mol−1) than 4MgH2-NaAlH4 (159 kJ mol−1), indicating an enhanced dehydrogenation kinetics due to the additional TiH2. TiH2 catalyzes the decomposition of MgH2 and NaAlH4, respectively, and also the reaction between their products during the dehydrogenation process below 375 °C. At temperatures above 375 °C, TiH2 will react with Mg17Al12 to form Al3Ti and liberate contained hydrogen. TiH2 also improved the isothermal hydrogenation kinetics of 4MgH2-NaAlH4 desorbed system. The activation energy of re-hydrogenation for 4MgH2-NaAlH4-TiH2 system was greatly reduced from 161.62 kJ mol−1 H2 to 125.80 kJ mol−1 H2 of 4MgH2-NaAlH4. The kinetics enhancement of hydrogen absorption is probably due to the intermediate phase Al3Ti, which is beneficial to the recombination of MgH2.

In this work, titanium dioxide surface modified montmorillonite (TMC) were prepared by sol–gel method, so as to improve its selective adsorptivity for trivalent chromium ions (Cr3+). When it was applied to remove low concentration of Cr3+(10 mg/L) from wastewater, the remaining concentration of Cr3+ was less than 1.5 mg/L, meeting the emission standard required by the Chinese Environmental protection agency (GB4287-92). The phase, structure and morphology of TMC were determined by means of XRD, CEC, IR, Raman, XPS, SEM, TEM and BET. It was found that titanium dioxide (TiO2) was uniformly dispersed on the surface of montmorillonite (MMT), and the spacing of MMT layer was almost unchanged via filling with Na+, so that the selective adsorptivity of MMT for Cr3+ was achieved. At the same time, theoretical calculations based on first principles and density functional theory confirmed the adsorption selectivity of MMT for Cr3+. In addition, the structural advantages of TMC addressed the shortcomings of MMT surface negative potential that it could not perform adsorption selectivity. Moreover, the adsorptive process of Cr3+ with TMC followed the pesudo-second-order kinetic equation, and Langmuir equation could better describe the adsorption mechanism (the maximum adsorption capacity was 194.1 mg/g). After five cycles, the removing efficiency was still over 89%. Therefore, TMC accompanied with high selective adsorptivity, simple synthesis process, as well as high regenerative performance, had great potential for removing low concentration of Cr3+ from wastewater.

Montmorillonite (MMT), with many excellent features, such as nano-layered structure, ion exchange ability and high hydrophilicity, could be considered as a kind of modified materials, so it is widely applied in many fields. In this study, novel photocatalyst material-TMC, is synthesized via the method of filling cations, accomplishing with prepared by loading TiO2 on the surface of MMT, which is proposed to remove Rhodamine B (Rh-B) via photocatalytic degradation. In the preparing process, the negative potential of MMT plays an important role in uniformly distributing TiO2 as well as limiting the size of distributed particles. Meanwhile, obtaining more oxygen vacancies could be attributed to optimal by screen calcination temperature. In addition, the specific surface area of TMC is measured to be three times larger than that of single TiO2. Furthermore, coupled with UV-DRS, FT-IR, XPS and PL, it is confirmed that Ti-O-Si bonds have been formed, and the narrowest bandgap (2.79 eV) is formed with the sample that calcinated at 450 °C. Meanwhile, the positions of conduction band and valence band with TMC contribute that it reaches higher Fermi level as compared with single TiO2. In addition, the negative potential (on the surface of MMT) acts as effectively extending the recombination time between electrons (e-) and holes (h+), so that the transferred photoelectrons can directly form O2− to degrade Rh-B that adsorbed on the surface of MMT. Finally, the main free radical scavenging experiment is conducted to indicate that O2− and OH are the dominant free radicals that involve in photocatalytic process, and the degradation pathways for Rh-B are speculated with characterization of HPLC-MS.

Constructing bioactive guided bone regeneration (GBR) membranes that possess biological multifunctionality is becoming increasingly attractive and promising to meet higher requirements for bone healing. Given the biological responses following implantation, GBR process originates from an early inflammation-driven reaction adjacent to implanted membranes surface. However, to date there is relatively little attention paid to the critical immunoregulatory functions in traditionally designed GBR membranes. Herein, for the first time, we manipulate immunomodulatory properties of the widely-used native small intestinal submucosa (SIS) membrane by incorporating strontium-substituted nanohydroxyapatite coatings and/or IFN-γ to its surface. In vitro results reveal the obtained novel membrane SIS/SrHA/IFN-γ not only promote functions of endothelial cells and osteoblasts directly, but also energetically mediate a sequential M1-M2 macrophages transition to concurrently facilitate angiogenesis and osteogenesis. Moreover, in vivo outcomes of subcutaneous implantation and cranial defects repair further confirm its superior capacity to promote vascularization and in situ bone regeneration than pristine SIS through immunomodulation. These results demonstrate a sequential immunomodulatory strategy renders modified SIS membranes acting as a robust immunomodulator rather than a traditional barrier to significantly ameliorate in vivo GBR outcomes and hence provide important implications that may facilitate concerns on immunomodulatory properties for future GBR developments.

A porous three-dimensional (3D) graphene oxide-montmorillonite/sodium alginate (GO-MMT/SA) aerogel beads have been prepared by a simple method of cross-linking and freeze-drying, which is used to selectively adsorb methylene blue (MB) in aqueous solution. In addition, the properties of GO-MMT/SA aerogel beads are characterized by FTIR, Raman, TG, BET, SEM and XPS. Characterization results show that GO-MMT/SA aerogel beads obtain an integral porous structure and a larger specific surface area. The three-dimensional network of as-prepared aerogel beads is formed by the strong interaction between the –COO– in SA and Ca2+ ions. Interestingly, it is found there are chemical crosslinking and hydrogen bonds among MMT, GO and SA under our experiment condition. In different conditions, a series of adsorption experiments on the GO-MMT/SA aerogel beads for the removal of MB are carried out. GO-MMT/SA aerogel beads show better adsorption capacities toward MB, and poor adsorption capacities for rhodamineB and methyl orange. The pseudo-second-order kinetic equation and Freundlich equation can appropriately describe the adsorption process. Furthermore, the possible adsorption mechanism of GO-MMT/SA aerogel beads for MB is also proposed based on the experimental results.

Titanium dioxide (TiO2) is widely used as coating in polymer materials due to its high visible light transmittance, long-term chemical stability and low cost. However, these materials are easily to generate electrostatic discharge and fire because of friction or collision. In order to prevent the damage, TiO2 is required to improve electrical conductivity. Herein, TiO2/G/Ca2+ (TGC) conductive composites are synthesized by self-assembly method on the basis of TiO2/G (TG) composites. The conductivity of TGC nanocomposites is significantly enhanced in comparison with TG, and the lowest resistivity is 0.58 Ω cm. The increased electrical conductivity of TGC composites can be attributed to the three-dimensional conductive network achieved by Ca2+ bridging graphene (G) sheets to create new electron energy levels and conduction channels. This strategy can provide a novel approach to enhance the conductivity of TiO2-based conductive materials and facilitate its application in coating field.

Production of menaquinone-7 (MK-7) by Bacillus subtilis natto is associated with major drawbacks. To address the current challenges in MK-7 fermentation, studying the effect of magnetic nanoparticles on the bacterial cells can open up a new domain for intensified bioprocesses. This article introduces the new concept of application of iron oxide nanoparticles (IONs) as a pioneer tool for MK-7 process intensification. In this order, IONs with the average size of 11 nm were successfully fabricated and characterized for possible in situ removal of target substances from the fermentation media. The prepared particles were used for decoration and immobilization of B. subtilis natto cells. Presence of iron oxide nanoparticles significantly enhanced the MK-7 specific yield (15 %) as compared to the control samples. In addition, fabricated IONs showed a promising ability for in situ recovery of bacterial cells from the fermentation media with more than 95 % capture efficiency. Based on the results, IONs can be implemented successfully as a novel tool for MK-7 production. This study provides a considerable interest for industrial application of magnetic nanoparticles and their future role in designing an intensified biological process.

Crashworthiness is an increasingly important design consideration for operational hard disk drive (HDD). The simulation model of HDD is first investigated by the finite element method. Maximum flying height, pitch angle and roll angle, maximum stress are put forward as indexes for HDD response to drop impact. Sometime, these indexes are crashworthiness evaluation parameters. The drop impact response of the finite element model under different surface drops and different angle drops are presented. Simulation results are proven to be fundamental method of crashworthiness analysis, evaluation and design for HDD.

To develop bioactive bone graft materials that can induce rapid bone regeneration, a novel biomaterial was synthesized by coating true bone ceramic (TBC) substrates with strontium-substituted nano-hydroxyapatites (SrHA) (Sr concentrations of 0%, 10%, 40%, 100%) through a sol–gel dip-coating approach. All coated TBC scaffolds retained the inherent natural trabecular structure, porosity, compressive strength and simultaneously possessed a micro/nanotopography SrHA layer on the substrate surface. The dimension of the deposited crystal increased and the density of the deposited apatite particles became sparse with increasing Sr content, but a unique HA crystalline phase was observed under all conditions. The modified TBC scaffolds significantly enhanced the adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 osteoblasts in vitro. Particularly, the Sr10-TBC group (10 mol% Sr2+ in apatite coating) revealed the highest osteogenic efficacy over the other groups. Three-dimensional CT imaging and histological evaluations on a bilateral critical-sized rabbit radial defect model for 12 weeks showed significant bone formation in the Sr10-TBC implants. The new bone area ratios of the Sr10-TBC group were significantly higher than that of the TBC group. Additionally, Sr10-TBC implants showed faster degradability compared with raw TBC implants during the 12 weeks of implantation. The results indicate that TBC modification with 10% SrHA coating stimulated osteogenesis and could be a promising biomaterial for future bone defect regeneration.

Single-walled carbon nanotubes (SWNTs) are a promising material for flexible and printed electronics. Efficient dispersion and sorting methods facilitate the production of large quantities of high-quality semiconducting SWNT inks for direct printing. Here, the suitability of aerosol-jet printing of polymer-sorted (6,5) SWNTs for top-gate field-effect transistors is investigated. Despite the sonication involved in the printing process, almost no impact on the quality of the SWNTs in terms of defects and length is found. Printed network transistors show reproducible device performance over extended printing periods and for different ink batches with constant printing parameters. Deposition of multiple SWNT layers to obtain thicker and optically dense films increases the effective mobility and on-conductance, while also decreasing hysteresis. Aerosol-jet printing of SWNTs is thus suitable for the fabrication of integrated circuits based on nanotube transistors.