Vanadium (V) bio-detoxification based on washing water of rice as microbial and carbon sources

Mining and smelting result in vanadium (V) being released into the environment. Biologically removing V(V) with washing water of rice (WWR) was investigated in this study. Over a 7-d trial, the V(V) removal efficiency increased with dosing washing water of rice dosage up to 56.6%. The results demonstrated that washing water of rice could be used as carbon and microbial sources for biologically reducing V(V). Using domesticated sludge as the inoculum could enhance V(V) detoxification performance, and 95.5% of V(V) was removed in the inoculated system for 5 d. Soluble V(V) was transformed into insoluble V(IV) (VO2), which could be further removed with precipitation. In addition to ABC transporters, a two-component system was also involved in V(V) reduction. The study confirmed that washing water of rice could be utilized for V(V) bio-detoxification

Triboelectric effect based instantaneous self-powered wireless sensing with self-determined identity

Sensors are the foundation of modern Internet of Things, artificial intelligent, smart manufacturing etc, but most of them require power to operate without spontaneous unique identifiable function. Herein we propose a novel instantaneous force-driven self-powered self-identified wireless sensor based on triboelectric effect to meet the huge demand of true self-powered wireless sensors. The device consists of a microswitch controlled triboelectric nanogenerator (TENG) in parallel with a capacitor-inductor oscillating circuit, and a wireless transmitter. The system is fully powered by the output of the TENG to generate a resonant frequency containing sensing and device identity information, which is then coupled to the transmitter for realizing a long-range wireless communication. The device, with the multiple functions of energy harvesting, sensing, identity generation and wireless signal transmission, is a standalone device, which responds to each trigger without losing sensing information. It eliminates the requirement of electric components for traditional wireless communication, such as rectification circuit, energy storage units, microprocessor, wireless communication chip, etc. Thus, we developed a true self-powered identifiable wireless sensor with great potential for widespread applications

Highly stable double crosslinked membrane based on poly(vinylbenzyl chloride) for anion exchange membrane fuel cell

Anion exchange membranes (AEMs) with high ionic conductivity and excellent stability are critical for long-life AEM fuel cells. In this paper, a novel double crosslinked AEM was prepared successfully based on polybenzimidazole (PBI) and poly(vinylbenzyl chloride) (PVBC) with N,N,N,N-tetramethyl-1,6-hexanediamine as a homogeneous quaternization reagent. As the mass ratios of PBI and PVBC increased from 1:1 to 3:1, the water uptake and swelling ratio of AEM decreased by half, while the ionic exchange capacity had a small reduction. Moreover, little change occurred in water uptake and swelling ratio under elevated temperature, as well as the ionic exchange capacity after soaking in KOH for 500h. When the mass ratios of PBI and PVBC was 1:1, the AEM showed the minimum tensile strength of 45.8MPa and highest conductivity of 31.5mScm(-1) at 20 degrees C and 68.8mScm(-1) at 80 degrees C. In addition, excellent alkali resistance and oxidative stability were reflected in durability studies and the maximum power density of an H-2/O-2 single fuel cell using the AEM reached 244.93mWcm(-2) at 0.54V

Performance and Enhancement of Various Fillers Guiding Vanadium (V) Bioremediation

Bioremediation of vanadium (V) pollution in groundwater is an emerging topic. However, knowledge of V in a biogeochemical process is limited and long-term effective removal methods are lacking. V(V) remediation processes by various kinds of auxiliary fillers (maifanite-1, maifanite-2, volcanic rock, green zeolite and ceramsite), agricultural biomass and microbial enhancing were explored in this study. In tests without inocula, the V(V) removal efficiencies of ceramsite (inert filler) and maifanite-2 (active filler) were 84.9% and 60.5%, respectively. When inoculated with anaerobic sludge, 99.9% of V(V) could be removed with the synergistic performance of straw and maifanite-2. TOC (Total Organic Carbon), trace elements and three-dimensional fluorescence analyses confirmed that maifanite-2 was the most suitable among various fillers in biological V(V) removal systems with straw. This study provides a collaborative method (adsorption–biology) by using straw with maifanite-2 in V(V)-contaminated groundwater. The knowledge gained in this study will help develop permeable reactive barrier technology to repair polluted groundwater to put forward a reasonable, effective and sustainable environmental treatment strategy

Influences of Multicenter Bonding and Interstitial Elements on Twinned γ-TiAl Crystal

The bonding properties of the twin boundary in polysynthetic twinned γ-TiAl crystal and the effect of interstitial alloy elements on it are investigated by first principles. Among the three different kinds of interface relationships in the γ/γ interface, the proportion of true twin boundaries is the highest because it has the lowest interfacial energy, the reason for which is discussed by local energy and three-center bond. The presence of the interstitial atoms C, N, H, and O induces the competition for domination between their affinity to host atoms and three-center bonds, which eventually influences the values of unstable stacking fault energy (USFE) and intrinsic stacking fault energy (ISFE). The relative importance of different bonding with different alloy elements is clarified based on the analysis of local energy combined with Electron Localization Function (ELF) and Quantum Theory of Atoms in Molecules (QTAIM) schemes

Significantly Enhanced Performance of Triboelectric Nanogenerator by Incorporating BaTiO3 Nanoparticles in Poly(vinylidene fluoride) Film

Triboelectric nanogenerators (TENGs) have received significant attention in recent years due to their renewable and sustainable properties. They convert mechanical energy into electric energy through contact and separation of two dissimilar materials. Many methods have been developed to improve the performance of TENGs, but little attention has been paid to use nanoparticles such as BaTiO3 (BTO) with high dielectric constant for enhancing the performance. This paper reports the achievement of significant performance enhancement of poly(vinylidene fluoride) (PVDF)/polyamide‐6 (PA6) TENGs by incorporating BTO nanoparticles into the PVDF film. The PVDF‐BTO/PA6 TENG with 10 wt% BTO nanoparticles shows the best results with a peak voltage and charge density up to 900 V and 34.4 μC m−2 at contact frequency of 5 Hz when the contact force and the spacer distance are 180 N and 100 mm, which are much higher than 384 V and 26.4 μC m−2 of the PVDF/PA6 TENG without incorporating BTO nanoparticles. Further increase in the BTO concentration deteriorates the output performance of the TENGs. Detailed investigations on the piezo‐response and permittivity of the PVDF‐BTO films show that the increased piezoelectric constant and permittivity are responsible for the significantly enhanced performance of the TENGs. A mathematical model has been developed to describe the output voltages of the TENG as a function of thickness of the PVDF‐BTO film

Fabrication of N1-butyl substituted 4,5-dimethyl-imidazole based crosslinked anion exchange membranes for fuel cells

Novel N1, C4, C5-substituted imidazolium-based crosslinked anion exchange membranes (AEMs) are prepared by the incorporation of polybenzimidazole (PBI) into the poly(vinylbenzyl chloride) (PVBC) matrix. 1-Butyl-4,5-dimethyl- imidazole (BDIm) with methyl substituents at C4, C5 and long side alkyl substituents at N1 is firstly synthesized to enhance the stability of AEMs by steric hindrance and hyperconjugative effects and characterized by H-1 NMR. The effects of crosslinking density of AEMs on the hydroxide conductivity, swelling ratio, thermal stability, oxidative and alkaline stability are evaluated in detail for fuel cell applications. The results reveal that the crosslinking structure between PVBC and PBI plays a vital role in achieving both good mechanical properties and low swelling ratio. Notably, the AEM containing 66.7% PVBC has the highest ionic conductivity of 16.1 mS cm(-1) at 20 degrees C with an IEC of 2.1 mmol g(-1). Meanwhile, the AEMs also exhibit excellent oxidative stability in Fenton's reagent for 200 h and alkaline stability in 1 mol L-1 KOH at 60 degrees C for 480 h. Furthermore, the peak power density of an H-2/O-2 single fuel cell is up to 54 mW cm(-2)

Functionalization of polybenzimidazole-crosslinked poly(vinylbenzyl chloride) with two cyclic quaternary ammonium cations for anion exchange membranes

The anion exchange membranes (AEMs) with both high ionic conductivity and good stability is always the research focus role for the long-term use of AEM fuel cells. A series of the mechanically and chemically stable PVBC/PBI crosslinked membranes, functionalized with N1-butyl substituted BDABCO groups, were designed, prepared and characterized. With the crosslinking by polybenzimidazole (PBI), the membranes showed good flexibility, strength and low swelling ratio (less than 18%). N1-butyl substituted doubly-charged BDABCO was introduced in the AEMs during the crosslinking reaction instead of the traditional dipping method, benefiting from the improvement compatibility between polymers and BDABCO groups. Attributing to the well-developed phase separation between hydrophilic domains and hydrophobic domains, the family of synthesized AEMs exhibited the higher conductivities than that of DABCO based membranes, which was proved by TEM and SAXS. The M-BDABCO-OH-1: 3 with high BDABCO content displayed the highest ionic conductivity of 29.3 and 91.4 mS cm(-1) at 20 and 80 degrees C, respectively. The results of alkaline stability showed that the membranes had the superior chemical stability after immersing in a 1 mol L-1 KOH at 60 degrees C solution for more than 550 h. Furthermore, the peak power density of an H-2/O-2 single fuel cell using the optimized M-BDABCO-OHAEMFCs-1: 3 was up to 340 mW cm(-2) at 0.492 V with the EIS consisting of membrane resistance less than 0.1 Omega cm(2) which was much smaller than the other AEMs. Overall, the developed membranes demonstrated the superior performance and would be a promising candidate material for AEMFCs

Controlled Synthesis of Tb³⁺/Eu³⁺ Co-Doped Gd₂O₃ Phosphors with Enhanced Red Emission

(Gd0.93−xTb0.07Eux)2O3 (x = 0⁻0.10) phosphors shows great potential for applications in the lighting and display areas. (Gd0.93−xTb0.07Eux)2O3 phosphors with controlled morphology were prepared by a hydrothermal method, followed by calcination at 1100 °C. XRD, FE-SEM, PL/PLE, luminescent decay analysis and thermal stability have been performed to investigate the Eu3+ content and the effects of hydrothermal conditions on the phase variation, microstructure, luminescent properties and energy transfer. Optimum excitation wavelength at ~308 nm nanometer ascribed to the 4f8-4f75d1 transition of Tb3+, the (Gd0.93−xTb0.07Eux)2O3 phosphors display both Tb3+and Eu3+ emission with the strongest emission band at ~611 nm. For increasing Eu3+ content, the Eu3+ emission intensity increased as well while the Tb3+ emission intensity decreased owing to Tb3+→Eu3+ energy transfer. The energy transfer efficiencies were calculated and the energy transfer mechanism was discussed in detail. The lifetime for both the Eu3+ and Tb3+ emission decreases with the Eu3+ addition, the former is due to the formation of resonant energy transfer net, and the latter is because of contribution by Tb3+→Eu3+ energy transfer. The phosphor morphology can be controlled by adjusting the hydrothermal condition (reaction pH), and the morphological influence to the luminescent properties (PL/PLE, decay lifetime, etc.) has been studied in detail

Enhanced durability of sulfonated poly (ether ether ketones)-based polymer electrolyte membranes by a multi-layer composite technology

Multi-layer composite membrane with low-cost and high durability is prepared via hot-spraying methods for proton exchange membrane fuel cell (PEMFC) applications, which consists of a mid layer of sulfonated poly (ether ether ketones) (SPEEK), two transition layers (TLs) and two PFSA outer layers (PLs). Here, PLs can protect SPEEK membrane against the chemical degradation from reactive oxygen species and endow the composite membrane with high chemical stability. TLs improve the interfacial compatibility between SPEEK membrane and PLs, avoiding the delamination problem. This multi-layer composite membrane exhibits a proper ion-exchange capacity (IEC) and higher proton conductivity compared with that of SPEEK membrane, and it also keeps a balance between water uptake and swelling ratio owing to the presence of the multi-layer structure. Besides, the lower cost of the composite membrane is confirmed due to the small content of Nafion. Single cell tests indicate that the multi-layer composite membrane has better cell performance than that of SPEEK membrane. The higher durability for the membrane under accelerated open circuit voltage (OCV) tests reveals the effectiveness of this multi-layer composite strategy in improving the chemical durability of the SPEEK membrane