Cycling Time Research Articles

Enhanced Electrochemical Performance of Supercapacitors via Atomic Layer Deposition of ZnO on the Activated Carbon Electrode Material.

Fabricating electrical double-layer capacitors (EDLCs) with high energy density for various applications has been of great interest in recent years. However, activated carbon (AC) electrodes are restricted to a lower operating voltage because they suffer from instability above a threshold potential window. Thus, they are limited in their energy storage. The deposition of inorganic compounds’ atomic layer deposition (ALD) aiming to enhance cycling performance of supercapacitors and battery electrodes can be applied to the AC electrode materials. Here, we report on the investigation of zinc oxide (ZnO) coating strategy in terms of different pulse times of precursors, ALD cycles, and deposition temperatures to ensure high electrical conductivity and capacitance retention without blocking the micropores of the AC electrode. Crystalline ZnO phase with its optimal forming condition is obtained preferably using a longer precursor pulse time. Supercapacitors comprising AC electrodes coated with 20 cycles of ALD ZnO at 70 °C and operated in TEABF4/acetonitrile organic electrolyte show a specific capacitance of 23.13 F g−1 at 5 mA cm−2 and enhanced capacitance retention at 3.2 V, which well exceeds the normal working voltage of a commercial EDLC product (2.7 V). This work delivers an additional feasible approach of using ZnO ALD modification of AC materials, enhancing and promoting stable EDLC cells under high working voltages.

Effect of a day-trip to altitude (2500 m) on exercise performance in pulmonary hypertension: randomised crossover trial

Question addressed by the studyTo investigate exercise performance and hypoxia-related health effects in patients with pulmonary hypertension (PH) during a high-altitude sojourn.Patients and methodsIn a randomised crossover trial in stable (same therapy for >4 weeks) patients with pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH) with resting arterial oxygen tension (PaO2) ≥7.3 kPa, we compared symptom-limited constant work-rate exercise test (CWRET) cycling time during a day-trip to 2500 m versus 470 m. Further outcomes were symptoms, oxygenation and echocardiography. For safety, patients with sustained hypoxaemia at altitude (peripheral oxygen saturation <80% for >30 min or <75% for >15 min) received oxygen therapy.Results28 PAH/CTEPH patients (n=15/n=13); 13 females; mean±sd age 63±15 years were included. After >3 h at 2500 m versus 470 m, CWRET-time was reduced to 17±11 versus 24±9 min (mean difference −6, 95% CI −10 to −3), corresponding to −27.6% (−41.1 to −14.1; p<0.001), but similar Borg dyspnoea scale. At altitude, PaO2 was significantly lower (7.3±0.8 versus 10.4±1.5 kPa; mean difference −3.2 kPa, 95% CI −3.6 to −2.8 kPa), whereas heart rate and tricuspid regurgitation pressure gradient (TRPG) were higher (86±18 versus 71±16 beats·min−1, mean difference 15 beats·min−1, 95% CI 7 to 23 beats·min−1) and 56±25 versus 40±15 mmHg (mean difference 17 mmHg, 95% CI 9 to 24 mmHg), respectively, and remained so until end-exercise (all p<0.001). The TRPG/cardiac output slope during exercise was similar at both altitudes. Overall, three (11%) out of 28 patients received oxygen at 2500 m due to hypoxaemia.ConclusionThis randomised crossover study showed that the majority of PH patients tolerate a day-trip to 2500 m well. At high versus low altitude, the mean exercise time was reduced, albeit with a high interindividual variability, and pulmonary artery pressure at rest and during exercise increased, but pressure–flow slope and dyspnoea were unchanged.

Effects of prior high-intensity endurance exercise in subsequent 4-km cycling time trial performance and fatigue development

To investigate the effects of prior high-intensity endurance exercise on time trial (TT) performance and fatigue responses. Eleven male cyclists visited the lab in two separate visits. The first visit was composed by a maximal cycling incremental test (MIT) followed by 15 min of passive rest before a 4-km cycling TT. The second visit (control, CON) was composed by moderate-intensity exercise for 5 min before the TT. Fatigue of knee extensors was assessed by isometric maximal voluntary contractions (IMVC), while the central (voluntary activation [VA]) and peripheral fatigue (peak torque of potentiated twitches [TwPt]) were evaluated using electrically-evoked contractions performed before and 1 min after the TT. Power output (PO), oxygen uptake (V̇O 2 ) and rating of perceived exertion (RPE) were recorded throughout the TT. TT performance (+2.6%) and average PO (+5.7%) improved in MIT compared to CON condition. While peripheral fatigue level was greater in MIT condition ( P < 0.05), the central fatigue was lower compared to CON condition ( P < 0.05). There were greater overall V̇O 2 values (3.9 ± 0.4 vs 3.6 ± 0.4 L·min −1 ) but similar RPE responses (15 ± 2 vs 15 ± 3 a.u.) in MIT compared to CON. These findings indicate that prior high-intensity endurance exercise has positive effects in subsequent TT performance compare to moderate-intensity warm-up, despite exacerbated peripheral fatigue development. This response might be driven by greater aerobic reliance and exertion tolerance. Étudier les effets d’un pré exercice d’endurance à haute intensité sur la performance chronométrique (PC) et la fatigue. Onze cyclistes masculins sont venus à deux reprises au laboratoire. La première session était composée d’un test triangulaire maximal (TTM) suivi de 15 min de récupération passive avant la PC de 4 km à vélo. La seconde session était d’un exercice d’intensité modérée pendant 5 mis avant la PC (la condition contrôle, CON). La fatigue des extenseurs du genou était évaluée avec des contractions volontaires maximales isométriques (CVMI), dans un même temps la fatigue centrale [activation volontaire (AC)] et périphérique [pic de force des potentiels des twitches (PfPT)] était évaluée en utilisant l’électrostimulation avant et 1 min après la PC. La consommation d’oxygène (V̇O 2 ) et évaluation de l’effort perçu (RPE) était mesurée pendant toute la durée de la PC. La PC (+2,6 %) et la PO moyenne (+5,7 %) se sont améliorées dans le MIT par rapport à la condition CON. Alors que le niveau de fatigue périphérique était plus élevé en condition MIT ( p < 0,05), la fatigue centrale était plus faible par rapport à la condition CON ( p < 0,05). Il y avait des valeurs de V̇O2 plus élevées (3,9 ± 0,4 vs 3,6 ± 0,4 L·min −1 ) mais des réponses RPE similaires (15 ± 2 vs 15 ± 3 ua) dans le TTM par rapport à CON. Ces résultats indiquent que les exercices d’endurance de haute intensité antérieure ont des effets positifs sur la PC subséquent par rapport à un échauffement d’intensité modérée, malgré un développement de fatigue périphérique exacerbé. Cette réponse pourrait être motivée par une plus grande dépendance aérobie et tolérance à l’effort.

Temporal interpretation of the world in dagestanian languages

The article deals with certain aspects of conceptualization of time, predetermined by the national specificity of the world perception. The topicality of the given study is accounted for by the extremely differentiated verbalization of space and time peculiar to the Dagestanian languages. The aim of the article is to identify the common origin of temporal and spatial vocabulary in the Dagestanian languages. To achieve the goal, the authors used a comparative-typological method, as well as a cognitive approach to reveal the role of national consciousness in conceptualization of time. The article also examines some aspects of national peculiarities of time conceptualization aimed at finding out the genetic connection between temporal and space vocabulary. The data under study allows claiming that in the basis of most lexemes with temporal meaning lies a semantic component denoting “space”. Temporal lexemes representing cycling time were developed by means of objectivation of the heavenly bodies’ movement. Meanwhile temporal vocabulary representing line time was formed by means of semantic conversion which allowed transforming local adverbs onto temporal. The most important results obtained by the authors are as follows: (a) the conceptualization of time in the Dagestanian languages is realized on the basis of spacial parameters, so the vocabulary of temporal semantics are formed on the basis of spatial vocabulary; b) the temporal vocabulary of the Dagestanian languages has evolved along the lines of spatial representations &gt; space-time representations&gt; time representations. The results achieved are important for the cognitive studies of the Dagestanian languages, as well as for the further description of the space and time conceptualization in the world language pictures.

In‐plane Defect Engineering Enabling Ultra‐stable Graphene Paper‐based Hosts for Lithium Metal Anodes

AbstractGraphene papers are widely studied as stable hosts to suppress lithium dendrite growth and accommodate the volumetric expansion for lithium metal anodes. Designing and constructing flexible graphene‐based films with unique structures as stable hosts in large scales for lithium metal anodes is challenging in terms of their realistic applications. Herein, scalable three‐dimensional (3D) holey reduced graphene oxide (HrGO) films with abundant as‐tailored oxygen functional groups on hole defects of graphene nanosheets are successfully constructed as stable hosts for lithium metal anodes. The as‐designed anodes deliver a stable voltage of 11 mV for 1900 h at a current density of 0.2 mA cm−2. The achieved cycling times of the optimized Li‐HrGO‐4 film anodes are over 1000 and 800 h at current densities of 0.5 and 1.0 mA cm−2, respectively. Simultaneously, the Li‐HrGO‐4 composite film anodes also exhibit superior rate performance as compared to pure lithium and Li‐rGO film anodes when utilized in symmetric cells. The as‐assembled LiFePO4/Li‐HrGO‐4 full cells show superior rate performance and retain capacity after 300 cycles at the rate of 1 C. Furthermore, first‐principles calculations indicate that C−O and O−C=O groups on defects of HrGO surfaces lead to excellent lithium affinity and uniform deposition. Above all, the unique 3D holey structure with as‐tailored oxygen defects and its design strategy holds a significant potential for the development of high energy‐dense and stable metal batteries.

Experimental study on mechanical properties of concrete under sub-high temperature cycles

Nuclear power plant containment, large storage tank, industrial cooling tower and some industrial plants under high temperature will be subjected to the sub-high temperature cycles from normal temperature to ~200°C. To explore the durability of the structural concrete, this paper carried out the experimental research on the mechanical properties of concrete under the cyclic environment of normal temperature to sub-high temperature (below 200°C). The uniaxial compression test of different strength concrete was carried out. The axial compressive strength grade ranged from 20 MPa to 70 MPa, and the changes in the appearance feature of concrete with different strengths after different number of times of sub-high temperature cycles were recorded. The evolution rules of mechanical parameters such as Young’s Modulus, peak strength, peak strain, and Poisson’s ratio under temperature cycles are obtained through uniaxial compression tests. The influence of sub-high temperature cycle on the macroscopic mechanical properties of concrete was studied. Moreover, the prediction formulas of mechanical parameters such as strength, peak strain, and Young’s modulus under different number of sub-high temperature cycles were established according to the test data.

Solid-state Li metal battery enabled by cold sintering at 120 °C

It is still a great challenge to fabricate dense solid electrolyte with high ionic conductivity using a facile and low-cost method for all solid-state rechargeable battery. In this context, a cold sintering process (CSP) is employed to prepare the ceramic solid electrolytes at an extremely low temperature of 120 °C, significantly suppressing the Li loss and impurity formation by traditionally high-temperature sintering. The low temperature prepared Li1.5Al0.5Ge1.5(PO4)3 (LAGP)-LiClO4 (10.0 wt%) composite electrolyte exhibits a high ionic conductivity of 6.35 × 10−5 S/cm, low activation energy of 0.26 eV and high relative densities of 90%. The Li | CSP LAGP-LiClO4 (10.0 wt%) | Li symmetric cell delivers a cycling time retention of over 350 h with a stabilized voltage overpotential at a current density of 0.2 mA/cm2. Moreover, the high Coulombic efficiency of 99.97% and capacity retention of 150 mAh/g are achieved after 130 cycles at 0.1C in Li | CSP LAGP-LiClO4 (10.0 wt%) | LiFePO4 solid cells. These good electrochemical performances are originated from the well-constructed solid electrolyte-electrode interfaces, where the electrochemically active interface demonstrates the powerful self-stabilization function to maintain the tight interface connection as well as the continuous Li ion transport. The CSP method sheds new light on the fabrication of solid electrolytes at a low temperature and inexpensive way, hence provides a rewarding avenue to fabricate better solid-state batteries and other electrochemical devices.

Silk fibroin hydrogel encapsulated graphene filed-effect transistors as enzyme-based biosensors

Graphene field-effect transistor (GFET) is a useful device which could be designed as an ultrasensitive and high-throughput biosensor in biological sensing. However, bioprobes like enzymes are easy to lose activity after immobilizing on the graphene. In addition, measurement of biomarkers in aqueous solutions with high ionic concentration and multiple interfering components is still a challenge. Here, the enzymatic cross-linked silk fibroin (SF) hydrogel is selected as a carrier for glucose oxidase and horseradish peroxidase to encapsulate GFET biosensor functionally, in order to detect glucose in a physiological buffer solution. The SF hydrogel showed the effects of prolonging the lifetime of these enzymes and enabled the reduction of nonspecific adsorption of the GFET. The SF hydrogel encapsulated GFET exhibited high sensitivity for glucose sensing with a wide detection range of 1 µM to 10 mM and a limit of detection (LOD) down 200 nM, as well as a high specificity over other carbohydrates such as sucrose and trehalose. Moreover, the biosensor has exhibited renewability, which maintained a consistent sensing response after 10 times of regenerative cycles, with a variation less than 4.9%. These results demonstrate that the strategy for encapsulating GFET using the SF hydrogel is valid, suggesting the potential application of the SF hydrogel in biosensors.

Ischemic Preconditioning: Modulating Pain Sensitivity and Exercise Performance.

Purpose The purpose of this study was to examine whether an individual’s IPC-mediated change in cold pain sensitivity is associated with the same individual’s IPC-mediated change in exercise performance.Methods Thirteen individuals (8 males; 5 females, 27 ± 7 years, 55 ± 5 ml.kgs–1.min–1) underwent two separate cold-water immersion tests: with preceding IPC treatment and without. In addition, each participant undertook two separate 5-km cycling time trials: with preceding IPC treatment and without. Pearson correlation coefficients were used to assess the relationship between an individual’s change in cold-water pain sensitivity following IPC with their change in 5-km time trial performance following IPC.Results During the cold-water immersion test, pain intensity increased over time (p < 0.001) but did not change with IPC (p = 0.96). However, IPC significantly reduced the total time spent under pain (−9 ± 7 s; p = 0.001) during the cold-water immersion test. No relationship was found between an individual’s change in time under pain (r = −0.2, p = 0.6) or pain intensity (r = −0.3, p = 0.3) following IPC and their change in performance following IPC.Conclusion These findings suggest that IPC can modulate sensitivity to a painful stimulus, but this altered sensitivity does not explain the ergogenic efficacy of IPC on 5-km cycling performance.

Durability of concrete members reinforced with steel-FRP composite bars under dry-wet cycles of seawater

To complete durability research on concrete members reinforced with steel-FRP composite bars (SFCBs), this paper examines the flexural behavior of these type of members conditioned with wet-dry cycles. The bonding and flexural behaviors of concrete members with changes in dry and wet cycling time, which were reinforced with steel bars and SFCBs, were compared by pullout tests and four-point bending tests, and beams were precracked before conditioning. The pullout specimens and bending specimens failed in the design mode of reinforcement pull-through and concrete crushing, respectively, and there were no changes as the condition time increased. The test results indicated that the maximum bond stress, stiffness and ductility of the SFCB-reinforced members increased as the age increased, whereas the characteristic loads and ability to control cracks weakened. Compared with RC members, SFCB-RC members performed better in terms of stiffness, capacity and crack control. The SFCB could be simplified as an FRP bar to calculate the flexural capacity, and the bond-dependent coefficient kb was equal to 1.10. For corrosion SFCB-RC beams with a short corrosion time, kb is less than 1.0.

Development of Improved Liming Process based on Automated pH Monitoring and Control System

The control of pH of a process plays an important role in many chemical or biological reactions. The monitoring and control of pH of processes like wastewater treatment, manufacturing food and leather making facilitate to reduce pollution and improve the quality of the final product. The focus of this study is to optimize the usage of lime and recycling of spent liquor through continuous monitoring system of pH to achieve near zero residue from liming operation. But the challenges are nonlinear behaviour of the system and frequent fouling of pH sensors. The system developed monitors the pH values and controls the cycling time and the addition of lime as per the user set profile. The real time data of pH values in the process is logged on to the PC for further analysis. The efficacy of the system developed was validated at lab level and can be easily scaled up for implementation in industries. The results showed that the effluent from leather making can be minimized by adopting automated pH monitoring and control systems.

Short Term, Oral Supplementation with Optimized Curcumin Does Not Impair Performance Improvements Associated with High Intensity Interval Training

Curcumin may improve athletic performance through a reduction in inflammation following exercise and improve mental states of well-being. The purpose of this investigation was to explore the effects of a 14 day HIIT intervention and oral supplementation with Longvida® optimized curcumin on athletic performance, lactate response, and well-being. Sixteen males and twenty females participated in a double-blinded, randomized, placebo-controlled trial to explore the effects of Longvida(R) optimized curcumin (1.0 g/day) and or a placebo (PLA) taken daily during a 14 day HIIT protocol. Participants were randomized into two groups, then evaluated in three groups, curcumin-fast (CURF), curcumin-slow (CURS) and placebo. Curcumin-fast and curcumin-slow were separated by their 16.1 km cycling time trial performance (TT) with CURF and CURS determined by a TT <30 min and >30 min at the pre intervention time point, respectively. Cycling time-trial performance, blood lactate response, and well-being assessments were determined at pre and post 14 day HIIT intervention time points. Blood lactate was recorded at baseline, 8.01 km, 15.1 km, and 1 min post, and 4 min post of the pre and post intervention TT. Following the internvetion, CONP and CURS experienced with 8.15% and 5.04% improvements in TT performance times, while CURF experienced a 0.57% improvement in TT performance time. No changes were observed with respect to other measures. When curcumin is taken daily in conjunction with 14 days of HIIT on a cycle ergometer, cycling performance in either well trained or more recreationally trained athletes is not impaired. Although the improvements in TT performance were not stasticially significant, they are noteworthy.

Distinct pacing profiles result in similar perceptual responses and neuromuscular fatigue development: Why different “roads” finish at the same line?

ABSTRACT The current study analysed the effect of distinct pacing profiles (i.e. U, J, and inverted J) in the perceptual responses and neuromuscular fatigue (NMF) development following a 4-km cycling time trial (TT). Twenty-one cyclists with similar training status were allocated into three different groups based on their pacing profile spontaneously adopted during TT. Rating of perceived exertion (RPE), oxygen uptake (⩒O2) and heart rate (HR) were continuously recorded. NMF was assessed by using isometric maximal voluntary contractions (IMVC), while the central [i.e. voluntary activation (VA)] and peripheral fatigue of knee extensors [i.e. peak torque of potentiated twitches (TwPt)] were evaluated using electrically evoked contractions performed pre and 2 min after the TT. TT performance was not different amongst pacing profiles (U = 377 ± 20 s; J = 392 ± 23 s; J-i = 381 ± 20 s) (all P > 0.05). RPE, ⩒O2 and HR increased similarly throughout the TT regardless the pacing strategy (all P > 0.05). Similarly, IMVC (U = −9.9 ± 8.8; J = −9.6 ± 4.5%; J-i = −13.8 ± 11.3%), VA (U = −2.3 ± 1.7%; J = −5.4 ± 2.2%; J-i = −6.4 ± 4.5%) and TwPt (U = −32.5 ± 12.0%; J = −29.5 ± 8.0%; J-i = −33.6 ± 13.6%) were similar amongst pacing profiles (all P > 0.05). Therefore, endurance athletes with similar training status showed the same perceived responses and NMF development regardless the pacing profile spontaneously adopted. It was suggested that these responses occurred in order to preserve a similar rate of change in systemic responses (i.e. RPE, ⩒O2 and HR) and NMF development, ultimately resulting in same TT performance. Highlights Different pacing profiles resulted in the same performance in a 4-km cycling time trial. The similar performance might be due to achievement of the same sensory tolerance limit. There was no difference for perceptual, metabolic and neuromuscular fatigue responses.

Silicon solar cells and modules with front contact paste containing copper‐based component

AbstractIn this article, we present the results of aging tests of silicon photovoltaic modules with a copper‐containing electrode deposited in one‐step screen printing method. For front metallization, a mixture of commercial silver paste with copper filler was used, where copper constituted 30% of total paste volume. The filler is based on copper particles about 1 μm of diameter covered with a protective coating layer based on nickel (CCu1) or nickel–silver (CCu2). For the first time, Si solar cells with screen‐printed front electrode containing massive copper with efficiency over 20% are reported. Aging tests included 2000 h of damp heat (DH) and 400 times of thermal cycling (TC) tests. TC results are very promising and provide slight deterioration of the electrical parameters of the modules with both CCu1 and CCu2. Greater decreases were found when performed DH tests, but it is worth pointing out that mainly fill factor (FF) and η have fallen while Voc and Isc did not change by more than 5% for both pastes. After 2000 h of the test, FF decreased by 28% for CCu1 and 37.4% for CCu2, whereas the efficiency deteriorated by 32% and 42.6% for CCu1 and CCu2. The electroluminescence (EL) and X‐ray photoelectron spectroscopy (XPS) measurements suggest that decrease in electrical parameters is a consequence of Cu corrosion caused by harmful products of the decomposed EVA laminating film.

Examining the associations between perceived built environment and active travel, before and after the COVID-19 outbreak in Shiraz city, Iran

This study aims to evaluate the effects of the COVID-19 pandemic and policies to control the outbreak such as quarantine, jobs closures, and traffic restrictions on active travel of Central Businesses District (CBD) residents in comparison with the non-CBD residents of Shiraz, Iran; and examine the relationship between perceived built environment factors and active travel in the pre- and post-outbreak. The results indicate that the most effective individuals factors on active travel are bicycle and car ownership, and built environment characteristics are walkability, bikeability, security, aesthetics, traffic calming, intersections safety, land uses diversity and density, destination accessibility, street pattern, and bike-sharing infrastructures. Also, the average walking and cycling time of the CBD residents before and after the outbreak is more than that of the non-CBD residents, which is due to the quality of built environment factors in the CBD. A built environment with mixed, diverse, dense and accessible land uses, as well as safe and secure cycling and walking routes have major effects on active travel in the crisis. Hence, it is suggested that policymakers take action to make the environment more people-friendly to maintain citizens' mobility in the critical situation, when many travel modes have lost their efficiency.

Fast and sensitive immuno-PCR assisted by plasmonic magnetic nanoparticles

Immunoassay for quantitative protein detection is an important tool in biomedical and clinical researches. Various types of detection platforms have emerged from typical ELISA using chromogenic reporter to more advanced approaches including electric, electrochemiluminescent and fluorogenic reporters to create quantitative analysis. Among them, fluorescence-based immuno-polymerase chain reaction (iPCR) is regarded as one of the simplest and most sensitive strategy that combines the specificity of immunological recognition technology with the amplification power of PCR. However, most PCR-based immunoassays to date have relied on the costly and time-consuming Peltier block heating technology. Here, we introduce a plasmonic photothermal (PPT)-iPCR assay method based on plasmonic magnetic nanoparticles to reduce the required thermal cycling time of amplification without compromising the superior sensitivity of iPCR. PPT-iPCR is capable of sensitive and quantitative detection of tumor necrosis factor-α (TNF-α) proteins ranging from 0.1 pg/mL to 1000 pg/mL within 8 min. PPT-iPCR uses fast, energy-efficient and inexpensive LED-based devices and can be used with commercial kits without modification while achieving excellent sensitivity. Our strategy can be easily combined with mobile phones or micro-optics, thus laying the foundation for the development of inexpensive, highly mobile detection devices that can quickly and accurately analyze biomarkers in a variety of diagnostic applications.

Characteristic comparison of stacked WC-based coatings prepared by high-velocity oxygen-fuel spray and electric contact strengthening

Homogeneous stacked WC-based coatings were prepared by high-velocity oxygen-fuel spray (HVOF) and electric contact strengthening (ECS). The microstructure, porosity, interfacial adhesion, phase composition and mechanical properties were investigated and evaluated. The thermal shock test was carried out to test the service performance under simulated thermal cycling working condition, and the interfacial bonding strength of the coating was indirectly compared. The results showed that the pores concentrated at the skin of ECS prepared coating, while those evenly distributed throughout the whole HVOF sprayed coating. With the layer stacked by ECS process, the existed pores in previous coating area were healed. The porosity of three-layer ECS coatings was 2.45%, which was much lower than that of HVOF coating. The interfacial bonding strength of ECS prepared coating was much better, according to morphology, scratch peaks, failure cycling times and residual interfacial phase in thermal shock test.

Cu–Fe embedded cross-linked 3D hydrogel for enhanced reductive removal of Cr(VI): Characterization, performance, and mechanisms

Porous hydrogel, as a high-efficiency adsorbent for heavy metals, suffers the drawbacks of the use of expensive and toxic reagents during the process of preparation, further limiting its application ranges. Besides, the heavy metals couldn't be transformed into nontoxic species, which leads to the environmental pollution risk. Herein, a three-dimensionally (3D) structured Cu–Fe embedded cross-linked cellulose hydrogel (nFeCu-CH) was innovatively fabricated by a novel self-assembly and in-situ reduction method, which exhibited exceptionally enhanced adsorption-reduction property towards Cr(VI) wastewater. The results of degradation experiment exhibited that the removal reaction followed Langmuir-Hinshelwood first order kinetic model and the degradation rate constant decreased with solution pH and initial Cr(VI) concentration, while increased with nFeCu-CH dosage and temperature. Regeneration studies demonstrated that more than 88% of Cr(VI) was removed by nFeCu-CH even after five times of cycling. nFeCu-CH exhibited excellent reductive activity, which had a close connection with the superiority of 3D crosslinked architectures and bimetallic synergistic effect. And 97.1% of Cr(VI) could be removed when nFeCu-CH dosage was 9.5 g/L, pH was 5, initial concentration of Cr(VI) was 20 mg/L and temperature was 303 K. Combined with cellulose hydrogel not only could provide additional active sites, but also could restrain the crystallite growth and agglomeration of nano-metallic particles, leading to the promotion of Cr(VI) removal. In addition, coating with Cu facilitated the generation and transformation of electrons according to the continuous redox cycles of Fe(III)/Fe(II) and Cu(II)/Cu(I), leading to the further improvement of the reductivity of nFeCu-CH. Multiple interaction mechanisms including adsorption, reduction and co-precipitation between nFeCu-CH and Cr(VI) were realized. The current work suggested that nFeCu-CH with highly reactive sites, excellent stability and recyclability was considered as an potential material for remediation of Cr(VI) contaminated wastewater.

Universal lithiophilic interfacial layers towards dendrite-free lithium anodes for solid-state lithium-metal batteries

Solid-state lithium-metal batteries (SSLMBs) using garnet Li6.4La3Zr1.4Ta0.6O12 (LLZTO) as the solid electrolyte are expected to conquer the safety concerns of high energy Li batteries with organic liquid electrolytes owing to its nonflammable nature and good mechanical strength. However, the poor interfacial contact between the Li anode and LLZTO greatly restrains the practical applications of the electrolyte, because large polarization, dendritic Li formation and penetration can occur at the interfaces. Here, an effective method is proposed to improve the wettability of the LLZTO toward lithium and reduce the interfacial resistance by engineering universal lithiophilic interfacial layers. Thanks to the in-situ formed lithiophilic and ionic conductive Co/Li2O interlayers, the symmetric Li/CoO-LLZTO/Li batteries present much smaller overpotential, ultra-low areal specific resistance (ASR, 12.3 Ω cm2), high critical current density (CCD, 1.1 mA cm−2), and outstanding cycling performance (1696 h at a current density of 0.3 mA cm−2) at 25 °C. Besides, the solid-state Li/CoO-LLZTO/LFP cells deliver an excellent electrochemical performance with a high coulombic efficiency of ~100% and a long cycling time over 185 times. Surprisingly, the high-voltage (4.6 V) solid state Li/CoO-LLZTO/Li1.4Mn0.6Ni0.2Co0.2O2.4 (LMNC622) batteries can also realize an ultra-high specific capacity (232.5 mAh g−1) under 0.1 C at 25 °C. This work paves an effective way for practical applications of the dendrite-free SSLMBs.

A continuous clinoptilolite augmented SBR-electrocoagulation process to remove concentrated ammonia and colour in landfill leachate

Novel single hybrid treatment of continuous clinoptilolite augmented electrocoagulation method integrated with a sequencing batch reactor (SBR) process was introduced to remove highly concentrated ammoniacal nitrogen (NH 3 -N) and colour in landfill leachate. First, the crystalline structures of the clinoptilolite were characterised via BET, XRD and XRF analyses, and the effects of different clinoptilolite dosages (13–187 g/L), reaction times (5–70 min) and settling times (5–60 min) on the removal efficiency of the pollutants were investigated. The kinetic mechanism of adsorption was found to correspond to a pseudo-second-order model (R 2 ≈ 1). Next, the regeneration of the spent clinoptilolite was examined using different types of solvents (NaCl, NaOH, HCl), solvent concentrations (0.1–1.0 M), contact times (5–70 min) and reuse numbers (1–5 runs). The highest NH 3 -N and colour removal rates were 83% and 95%, respectively, and the optimal removal rates were maintained over 300 min of continuous operations with a total treatment effluent amount exceeding 3750 mL. The most effective removal rates were achieved under optimum operating conditions of 147 g/L clinoptilolite, 60 min of reaction, 35 min of settling, NaCl as the regeneration solvent, 0.5 M solvent concentration, 25 min of contact and four times of reuse cycles. Cost estimations indicated that the overall operating cost for removing NH 3 -N and colour using the proposed process is US$8.71/m 3 /cycle. Thus, the integration of physical, chemical and biological methods into a single process may be a viable option to eliminate concentrated NH 3 -N and colour from landfill leachate. • Zeolite+electrocoagulation+SBR process was used to treat concentrated landfill leachate. • Excellent removal of NH 3 -N (83%) and colour (98%) was obtained at natural salinity. • The ion exchange and hydroxyl radical contribute to the high removal. • Zeolite utilisation rate was for five cycles with a recovery efficiency of up to 115%. • Economic analysis indicated a low operating cost with 8.71 US$/m 3 /cycles.