Structural characteristics and thermal performances of lauric-myristic-palmitic acid introduced into modified water hyacinth porous biochar for thermal energy storage.

Water hyacinth (WH) was used to prepare biochar for phase change energy storage field to realize encapsulation and enhance thermal conductivity of phase change materials (PCMs) in this work. The maximum specific surface area of modified water hyacinth biochar (MWB) obtained by lyophilization and carbonization at 900 °C was 479.966 m2/g. Lauric-myristic-palmitic acid (LMPA) was used as phase change energy storage material, LWB900 and VWB900 were used as porous carriers respectively. Modified water hyacinth biochar matrix composite phase change energy storage materials (MWB@CPCMs) were prepared by vacuum adsorption method, with loading rates of 80 % and 70 % respectively. The enthalpy of LMPA/LWB900 was 105.16 J/g, which was 25.79 % higher than that of LMPA/VWB900, and the energy storage efficiency was 99.1 %. Moreover, the introduction of LWB900 increased the thermal conductivity (k) of LMPA from 0.2528 W/(m·K) to 0.3574 W/(m·K). MWB@CPCMs have good temperature control capability, and the heating time of LMPA/LWB900 was 15.03 % higher than that of LMPA/VWB900. In addition, after 500 thermal cycles, the maximum change rate of enthalpy of LMPA/LWB900 was 6.56 %, and it maintains a phase change peak, showing better durability than LMPA/VWB900. This study shows that the preparation process of LWB900 is the best, and the adsorption of LMPA has high enthalpy value and stable thermal performance, realizing the sustainable development of biochar.

A Non-Resonant Piezoelectric-Electromagnetic-Triboelectric Hybrid Energy Harvester for Low-Frequency Human Motions.

With the rapid development of wireless communication and micro-power technologies, smart wearable devices with various functionalities appear more and more in our daily lives. Nevertheless, they normally possess short battery life and need to be recharged with external power sources with a long charging time, which seriously affects the user experience. To help extend the battery life or even replace it, a non-resonant piezoelectric-electromagnetic-triboelectric hybrid energy harvester is presented to effectively harvest energy from low-frequency human motions. In the designed structure, a moving magnet is used to simultaneously excite the three integrated energy collection units (i.e., piezoelectric, electromagnetic, and triboelectric) with a synergistic effect, such that the overall output power and energy-harvesting efficiency of the hybrid device can be greatly improved under various excitations. The experimental results show that with a vibration frequency of 4 Hz and a displacement of 200 mm, the hybrid energy harvester obtains a maximum output power of 26.17 mW at 70 kΩ for one piezoelectric generator (PEG) unit, 87.1 mW at 500 Ω for one electromagnetic generator (EMG) unit, and 63 µW at 140 MΩ for one triboelectric nanogenerator (TENG) unit, respectively. Then, the generated outputs are adopted for capacitor charging, which reveals that the performance of the three-unit integration is remarkably stronger than that of individual units. Finally, the practical energy-harvesting experiments conducted on various body parts such as wrist, calf, hand, and waist indicate that the proposed hybrid energy harvester has promising application potential in constructing a self-powered wearable system as the sustainable power source.

Visible light photocatalytic degradation of sulfanilamide enhanced by Mo doping of BiOBr nanoflowers.

Design of high-efficiency visible light photocatalysts is critical in the degradation of antibiotic pollutants in water, a key step towards environmental remediation. In the present study, Mo-doped BiOBr nanocomposites are prepared hydrothermally at different feed ratios, and display remarkable visible light photocatalytic activity towards the degradation of sulfanilamide, a common antibacterial drug. Among the series, the sample with 2% Mo dopants exhibits the best photocatalytic activity, with a performance 2.3 times better that of undoped BiOBr. This is attributed to Mo doping that narrows the band gap of BiOBr and enhances absorption in the visible region. Additional contributions arise from the unique materials morphology, where the highly exposed (102) crystal planes enrich the photocatalytic active sites, and facilitate the adsorption of sulfanilamide molecules and their eventual attack by free radicals. The reaction mechanism and pathways are then unraveled based on theoretical calculations of the Fukui index and liquid chromatography/mass spectrometry measurements of the reaction intermediates and products. Results from this study indicate that deliberate structural engineering based on heteroatom doping and morphological control may serve as an effective strategy in the design of highly active photocatalysts towards antibiotic degradation.

Chemical characterization of main bioactive constituents in Paeonia ostii seed meal and GC-MS analysis of seed oil.

The seeds of tree peony (Paeonia ostii) are promulgated as emerging edible oil crops. However, biological properties of principal constituents of peony seeds were not well studied. Fifteen main constituents including suffruticosols A and B, trans-ε-viniferin, ampelopsin E, resveratrol, trans-resveratrol-4'-O-ß-d-glucopyranoside, paeoniflorin, luteolin, luteolin-4'-O-ß-d-glucopyranoside, apigenin, kaempferol, oleanic acid, betulinic acid, hederagenin, and caffeic acid were isolated and identified. Their cytotoxicity against human tumor cell lines (COLO205, HT-29, HepG2, AGS, and HL-60) were evaluated. Among them, trans-ε-viniferin showed the most potent cytotoxicity against HL-60 cells (IC50 5.6 µM); ampelopsin E exhibited the most obvious antiproliferative properties on COLO205 (IC50 78.1 µM) and HT-29 (IC50 4.2 µM) cells, and betulinic acid showed the strongest growth inhibitory effects on HepG2 (IC50 6.6 µM) and AGS (IC50 5.4 µM) cells. Three enzymes (tyronsinase, α-glucosidase, and acetylcholinesterase) inhibitory activities of 12 compounds were also screened. Stilbene compounds, especially suffruticosols A and B, showed a significant inhibitory activity on all three enzymes. PRACTICAL APPLICATIONS: The cytotoxicity of 15 main constituents from peony seeds against COLO205, HT-29, HepG2, AGS, and HL-60 cells were evaluated. Among them, trans-ε-viniferin showed the most potent cytotoxicity against HL-60 cells (IC50 5.6 µM); ampelopsin E exhibited the most obvious antiproliferative properties on COLO205 (IC50 78.1 µM) and HT-29 (IC50 4.2 µM) cells, and betulinic acid showed the strongest growth inhibitory effects on HepG2 (IC50 6.6 µM) and AGS (IC50 5.4 µM) cells. Collectively, these results suggested that Paeonia ostii seed (POS) extracts are potential candidates for anticancer agents.

Laser irradiation-induced laminated graphene/MoS2 composites with synergistically improved tribological properties.

Engineering lubricant additives that have extraordinary friction reduction and anti-wear performance is critical to almost any modern mechanical machines. Here, we demonstrate the fabrication of laminated lubricant additives that can combine the advantages of zero-dimensional nanospheres and two-dimensional nanosheets. A simple in situ laser irradiation method is developed to prepare the laminated composite structure composed of ideally ultrasmooth MoS2 sub-microspheres embedded within multiple layers of graphene. These ultrasmooth MoS2 spheres within the laminated structure can change sliding friction into rolling friction under strong shear force created by moving contact surfaces to significantly reduce the friction. Meantime, the graphene layers can behave as 'protection pads' to efficiently avoid the formation of scars on the metal-to-metal contact surfaces. Overall, the laminated composites as lubricant additives synergistically improve the friction reduction and anti-wear properties. Additionally, due to the unique loosely packed laminated structure, the composites can stably disperse in the lubricant for more than 15 d and work under high temperatures without being oxidized. Such constructed laminated composites with outstanding tribological properties by an in situ laser irradiation method supply a new concept in designing lubricant additives that can combine the advantages of 0D and 2D structures.

Investigation of sulfur forms and transformation during the co-combustion of sewage sludge and coal using X-ray photoelectron spectroscopy.

X-ray photoelectron spectroscopy was used to investigate the characteristics and evolution of sulfur (S) in mixtures of bituminous coal and sewage sludge (SS) and their chars during isothermal combustion. Five groups of mixtures with SS content of 0%, 10%, 20%, 30% and 100%, were examined at different burn-off ratios (beta) of 0, 30%, 50%, 70% and 100%. The S in the coal mainly exist as the forms of mercaptan (S1), sulfide (S2), thiophene (S3), sulfoxide (S4), sulfone (S5) and sulfate (S6). During the coal combustion process, the content of S1 and S2 decreased, while that of S3 and S5 increased in the early stage and decreased in the late stage. The S4 content increased throughout the entire process of combustion. Small amount of S6 was detected, showing a fluctuated pattern. The trend of S1, S2, S5 and S6 in SS was alike with that in coal, whereas S4 decreased at the end of combustion. The changing process of S3 in SS was opposite to that of coal, while the composition of S in the mixtures resulted from the mixing of coal and SS. The transformation of each functional group during co-combustion were correlated with their transformation characteristics during the mono-combustion of coal and SS, and no obvious interaction was observed, which demonstrated that the coal-origin and SS-origin sulfur in mixtures kept their own characteristics in the combustion. SS may accumulate on the solid surface as alpha increase, resulting its significant influence on the evolution of each form of S. When alpha was low, most of the S-contained functional groups presented the characteristics of coal. The percentage of coal-origin functional groups declined as alpha increased. The transforming trends of most functional groups were similar with that of SS when alpha reached 30%.