Emission characteristics of biogenic volatile organic compounds (BVOCs) from dominant tree species in the subtropical pristine forests of China are extremely limited. Here we conducted in situ field measurements of BVOCs emissions from representative mature evergreen trees by using dynamic branch enclosures at four altitude gradients (600-1690 m a.s.l.) in the Nanling Mountains of southern China. Composition characteristics as well as seasonal and altitudinal variations were analyzed. Standardized emission rates and canopy-scale emission factors were then calculated. Results showed that BVOCs emission intensities in the wet season were generally higher than those in the dry season. Monoterpenes were the dominant BVOCs emitted from most broad-leaved trees, accounting for over 70% of the total. Schima superba, Yushania basihirsuta and Altingia chinensis had relatively high emission intensities and secondary pollutant formation potentials. The localized emission factors of isoprene were comparable to the defaults in the Model of Emissions of Gases and Aerosols from Nature (MEGAN), while emission factors of monoterpenes and sesquiterpenes were 2 to 58 times of those in the model. Our results can be used to update the current BVOCs emission inventory in MEGAN, thereby reducing the uncertainties of BVOCs emission estimations in forested regions of southern China.

Under the influence of climate change, the increasing occurrence of extreme weather events, such as heatwaves, has led to an enhanced frequency of ozone (O3) pollution issues. In August 2022, the Sichuan Basin (SCB), a typical large-scale geographical terrain located in southwestern China, experienced the most severe heatwave in the last 20 years. The heatwave led to substantial disparities in O3 levels across the region. Here, by integrating observations, machine learning, and numerical simulations, we aim to understand the diverse O3 formation mechanisms in two megacities, Chengdu (western location) and Chongqing (eastern location). Observational data showed that Chengdu experienced a consecutive 17 d period of O3 exceedance, in contrast to Chongqing, where O3 concentrations remained below the standard. Meteorological and precursor factors were assessed, highlighting high temperatures, intense solar radiation, and overnight accumulative pollutants as key contributors to O3 concentrations. The interplay of isoprene, temperature, and O3, alongside the observation-based box model and MEGAN simulations, underscored the significant role of intensified biogenic volatile organic compounds (BVOCs) in O3 formation. Interestingly, Chongqing exhibited nearly double the BVOC emissions of Chengdu, yet contributed less to O3 concentrations. This discrepancy was addressed through CMAQ-DDM (Decoupled Direct Method) simulations and satellite diagnosis by investigating the O3–NOx–VOC sensitivity. Notably, Chengdu displayed a VOC-driven sensitivity, while Chongqing showed a transitional regime. Moreover, the regional transport also played a pivotal role in the spatial divergence of O3 pollution. Cross-regional transport predominantly influenced Chongqing (contributing ∼ 80 %), whereas Chengdu was mainly affected by the emissions within the basin. The local accumulated pollutants gave rise to the atmospheric oxidizing capacity, resulting in a substantial photochemical contribution to O3 levels (49.9 ppbv h−1) in Chengdu. This comparison of the difference provides insights into the complex interplay of meteorology, natural emissions, and anthropogenic sources during heatwaves, guiding the necessity of targeted pollution control measures on regional scales.

Natural rubber latex (NRL)-based products often suffer from poor antibacterial performance, which limits their applications. Here, we fabricate NRL-based materials with enhanced antibacterial properties by incorporating natural plant extracts. Chinese herbal extracts/NRL compounds are prepared by compounding the relevant antibacterial natural plant extracts with the NRL, and the resulting mechanical properties and thermal stability are investigated. Mugwort/NRL and honeysuckle/NRL show the best antimicrobial effect, destroying the cell structure of various bacteria; no complete bacterial cells were found in the antimicrobial area. The excellent antibacterial properties,good cell compatibility and well-retained mechanical performance of the fabricated materials validate the proposed method as a novel, easy approach to preparing antibacterial NRL products. When the content of Chinese herbal extracts was 7.5 wt%, the Chinese herbal extracts/NR composites exhibited the best antibacterial and comprehensive mechanical properties. These products can be used in medical applications such as condoms, medical gloves, medical catheters and broaden the application of traditional Chinese herbal medicine. More importantly, the "template method" is proposed to rapidly determine the antibacterial ability of composite latex. This method can be applied to further scientific research and facilitate industrial production, providing strong technical support for developing more antibacterial latex products.

Carbonyls are ubiquitous in the troposphere and play a crucial role in atmospheric oxidation capacity (AOC), particularly in photochemistry-active regions such as the Tibetan Plateau (TP). However, the composition and evolution of carbonyls over the TP is still poorly understood due to a lack of comprehensive observations and modelling. Here, we conducted an intensive field measurement of 37 carbonyls and their precursors at a sub-urban site in Lhasa during summer 2022. Markedly higher levels of carbonyls (7.24 +/- 3.83 ppbv) were found during ozone pollution episodes, with 36 % higher than those during non-episodes. Formaldehyde was the most abundant carbonyl (38 %), which primarily originating from photochemical secondary formations. Simulations using the Rapid adaptive Optimization Model for Atmospheric Chemistry (ROMAC) indicated strong AOC in Lhasa, with the daytime maximum of center dot OH and center dot HO2 of 9.8 x 10(6) and 4.2 x 10(8) molecules cm(-3), respectively, which were even higher than that in most of the megacities in China. Notably, AOC significantly enhanced with the increasing carbonyls during the episodes, with the concentrations of center dot OH and center dot HO2 were boosted 21 % and 67 % than those during non-episodes, respectively. Budget analysis revealed that the center dot HO2 + NO (88 %) and center dot OH + VOC (74 %) pathways dominated the generation and loss of center dot OH, respectively. And for center dot HO2, they were center dot RO2 + NO (67 %) and center dot HO2 + NO (83 %). This study provides valuable insights into the strong AOC in the ecologically-fragile and climate-sensitive TP region, and highlighted the crucial role of anthropogenic-biogenic interactions in the active photochemistry of TP.

Functionalization of GO with an amphiphilic block copolymer is designed with an aim to enhance its biocompatibility, however, long copolymer chains can screen the blade effect of GO to sacrifice its antimicrobial activities. To solve this problem, low molecular weight of poly(ethylene glycol) (PEG), poly(3-hydroxybutyrate-co3-hydroxyvalerate) (PHBV) and their block copolymer were respectively introduced onto GO via an isophorone diisocyanate modified GO as a intermediate, followed by a solvent evaporation of an oil-in-water emulsion treatment (SE treatment) to induce block copolymer into polymer micelle via phase separation to refresh the sharp edges of GO. Block copolymer modified GO possessed similar dispersibility and stability to PEG modified GO, and even higher loading capacity of the hydrophobic drug than PHBV modified GO, illustrating its superior properties to homopolymer. PEG, PHBV and their block copolymer modified GO were nontoxic towards ATDC5 cells while cultured for 3 days and compatible with erythrocytes within 8 h. SE treatment enhanced greatly the loading capacity of the hydrophobic drug and the accumulative release reached 91.3% within 24 h. The inhibition zone of the block copolymer modified GO was 14.1 mm and 14.8 mm against E. coli and S. aureus, comparable to that of PEG modified GO. The bacterial reduction rate of the copolymer micelle modified GO was 87.1% and 82.7% towards E. coli and S. aureus, much greater than that of PEG, PHBV and their block copolymer modified GO at a concentration of 1 mg/mL. The antibiofilm capacity of the copolymer micelle modified GO were equal to that of PEG modified, demonstrating its great promise in tissue engineering application for repair of infected tissue defects.

Wormwood leaf is a traditional Chinese herbal medicine with a high medicinal value and long application history and its essential oil is a high-purity plant oil extracted from Wormwood leaf. Pharmacological research reveals that Wormwood leaf and Wormwood essential oil are a broad-spectrum antibacterial and antiviral drug, which can inhibit and kill many bacteria and viruses. We loaded wormwood extract on porous calcium carbonate (Porous-CaCO3) and introduced it and Wormwood essential oil into Natural rubber latex (NRL), thus synthesizing NRL composites with excellent vitro and in vivo antibacterial effect, cell compatibility and mechanical properties. This NRL material can delay the light aging and thermal oxidation of some mechanical properties, which provides a broader avenue for its commercialization.

The co-combustions of major waste streams such as textile dyeing sludge (TDS) and waste tires of shared bikes may reduce the dependence on fossil fuels, as well as enhance their circular management and the recovery of their value-added products. In this study, the ash-to-gas products, interaction effects, and reaction mechanisms of the co-combustions of TDS and waste tires were characterized. The mono-combustions included the three stages of water evaporation, volatiles release, and mineral decomposition for TDS and the five stages for both rubber (RT) and polyurethane (PUT) tires. The three substages of the main stage of volatiles release for TDS had the activation energy of 124.5, 144.9, and 167.5 kJ/mol and were best explained by the reaction mechanism models of D3, D5, and F2, respectively. The (co-)combustion performance indices rose with the increased heating rate. The blend of 25% TDS with 75% RT (TR) and 75% PUT (TP) led to the best co-combustion performance according to comprehensive combustion index, with TP outperforming TR. The co-combustions of TP and TR reduced the activation energy required for the main devolatilization stage reaction. There was no significant difference in the main reaction mechanisms between the co-combustions. The interaction between TDS and waste tires reduced the applied energy required for the main devolatilization stage. The co-combustions at the low temperature produced O-H, CH4, CO2, CO, SO2, NO, carbonyl products, olefin products, and ketones. The cocombustions increased the production of C-H, reduced SO2 release and the viscosity of their ashes, promoted the complete combustion of substances, and alleviated the scale and sintering issues regardless of TP versus TR and caused the early release of NO from TP. According to the thermodynamic equilibrium simulations, the TR cocombustion promoted the retentions of Ca, S, Si, and Fe, in particular, the fixation of S. The addition of PUT enhanced the combination of Ca and Si into CaSiO3. The optimization based on the artificial neural networks pointed to the temperature range of 400-800 oC and the TR co-combustion as the optimal operational conditions.

Investigating the formation mechanism of ozone (O3) during the Chinese National Day Holidays (CNDH, Oct. 1st to 7th) in the background area of megacity clusters provided a valuable opportunity for surveying the relative influence of anthropogenic and biogenic sources on O3 pollution. Here we conducted an intensive observation campaign during Sep. 24 to Oct. 14, 2021 at a regional background site in the Pearl River Delta region, southern China. Results showed that O3 concentrations exhibited a downtrend across the CNDH, with a decreasing rate of 14.8% from prior-CNDH to CNDH and 28.9% from CNDH to post-CNDH. Simulation of O3 photochemical process by using a photochemical box model with the master chemical mechanism (PBM-MCM) indicated that the decreased atmospheric oxidation capacity and decelerated free radical cycling led to a decrease in the net O3 production rate (PO3) across the CNDH. O3 isopleth diagrams and relative incremental reactivity (RIR) analysis revealed that O3 formation (FO3) in prior-CNDH and CNDH was jointly limited by VOCs and NOx, while was VOC-limited in post-CNDH. VOCs was still shown to be the largest contributor to FO3, suggesting VOCs reduction was the most effective way to reduce O3 pollution. Further simulation by combining the PBM-MCM and positive matrix factorization (PMF) model showed that anthropogenic sources have a smaller contribution to the PO3 in CNDH compared to the other periods, showing a significant holiday effect of “decreasing during holidays and rebounding after holidays”. However, due to the more biogenic emission during CNDH, the net PO3 was higher than that post-CNDH. This study improved our understanding of the enhanced biogenic contributions to FO3 in future scenarios of anthropogenic emissions reduction.

The massive industrial wastes of textile dyeing sludge (TDS) and waste shared bike tires are becoming increasingly problematic environmentally and economically. Their co-pyrolysis maybe an affordable and eco-friendlier alternative so as to reduce their waste volumes and emissions, as well as recover value-added oils and chars. This study was the first to characterize the TDS co-pyrolysis with rubber (RT) versus polyurethane (PUT) tires and their performances, mechanisms, emissions, oils, and chars as a function of temperature and blend type and ratio. The co-pyrolysis increased the total weight loss from 51.76% with TDS to 55.30% with 50% TDS and 50% RT (TR55) and to 68.92% with TP55. TR55 and TP55 yielded the best performances, with the stronger synergistic effect with the TP than TR co-pyrolysis. The optimal reaction models were second-order (F2) and five-dimension diffusion (D5) for the two devolatilization sub-stages for TDS, two thirds-order (F1.5) for the TR55 and the second and fourth sub-stages of the TP55, and F2 for the first and third sub-stages of the TP55. The co-pyrolysis reduced emissions of CO, SO2, and nitrous compounds, did not change their temperature dependency, and produced more hydrocarbon products. The TR co-pyrolysis produced more D-limonene and isoprene and inhibited the isomerization of D-limonene. The TP co-pyrolysis further decomposed diaminodiphenylmethane into low-molecular weight benzene series such as toluene and styrene. The co-pyrolytic chars had higher branching degree of aliphatic side chain and bridge bond, with the TP ones having the enhanced char aromaticity.

This study focused on an ozone pollution event occurring in winter (January) in Guangzhou. Various influencing factors were analyzed, including various atmospheric trace gases, meteorological conditions during the whole pollution process, as well as the characteristics of the main O3 precursor volatile organic compounds (VOCs). The main sources of VOCs and the O3 formation regime were analyzed using an array of tools:the ozone potential formation (OFP), positive matrix factorization (PMF) model, and empirical kinetic modeling approach (EKMA) curve. Feasible strategies for O3 control were suggested. The results showed that O3 and NO2 exceeded the corresponding standards in this winter pollution event, when the concentrations of PM10 and PM2.5 were also high, differing from the air pollution characteristics in summer and autumn. Low boundary layer height (<75 m) and high atmospheric stability at night exacerbated the accumulation of ozone precursors and fine particles. Meteorological conditions such as the increased daytime temperature (5℃), stronger solar radiation (10%), and low horizontal wind speed (<1 m·s-1) favored photochemical reactions and promoted the formation of ozone and fine particles. VOCs were mainly composed of alkanes, and the proportions of alkanes and alkynes in winter were higher than those in the other seasons. Aromatics (xylenes and toluene) and propylene were the key VOCs species leading to O3 formation. The main VOCs sources were vehicle exhaust (22.4%), solvent usage (20.5%), and industrial emissions (17.9%); however, the source with highest OFP was identified as solvent usage. O3 formation in this event was in the VOCs-limited regime, and reducing O3 precursors in the VOCs/NOx ratio of 3:1 was effective and feasible for O3 control. This study explored the causes of an O3 pollution event in winter, which will serve as reference for the synergistic control of O3 and PM2.5 in heavy pollution seasons.

Natural rubber latex (NRL) has prophylactic properties and is used to make pathogen-isolating products like condoms and surgical gloves. However, obtaining NRL and casting it into durable products are challenging. Consequently, progress in the research and development of medical NRL products has been slow. This study aims to strengthen NR and induce it with bactericidal properties. In this regard, we introduce inorganic whiskers into the NRL and synthesize whiskers/NR composites with strong mechanical and antibacterial properties. The method proposed herein is a template method, which can rapidly and efficiently reveal the antibacterial effect of the composite latex, providing convenience for research institutions and factories studying antibacterial latex. A complete system is established for studying the antibacterial medical NRL, and a precedent is set for the relevant products.

将硬脂酸钠改性四针状氧化锌晶须(Sodium stearate-T-ZnOw)超声分散液引入天然胶乳(NRL)基体中,制备了绿色环保的Sodium stearate-T-ZnOw/橡胶(NR)抗菌医用复合材料.系统研究了Sodium stearate-T-ZnOw/NR复合材料的综合力学性能、抗菌性能和热稳定性能.结果 表明:当Sodium stearate-T-ZnOw含量达3wt％时,Sodium sterate-T-ZnOw/NR复合材料的综合力学性能,相比纯胶,邵尔A硬度,300％定伸应力,拉伸强度,撕裂强度,断裂伸长率,提高了8.6％、25.4％、20.3％、25.6％、6.4％.此时,复合材料的热稳定性能也达到了最大值,相比纯胶,复合材料的起始热降解温度(To)和终止热降解温度(功分别比纯胶的T0和Tf提高了21.2℃和5.9℃.当Sodiumstearate-T-ZnOw含量超过3wt％时,其能在天然胶乳中充分发挥抑制大肠杆菌、金葡萄球菌、鲍曼不动杆菌、表皮葡萄球菌生长的能力,它可以进入细菌细胞,导致细胞壁被破坏,细胞内成分泄漏,细胞死亡.

The Magnesium sulfate whiskers (MOSw) were first modified by Stearic acid or Si69, and Natural rubber (NR)/ modified-MOSw composites were prepared by blending the modified-MOSw with natural rubber latex. By adding modified-MOSW into NR, the mechanical properties, the anti-ultraviolet aging property, flammability, and thermal stability of composites were improved obviously. The mechanical properties, crosslink density and thermal stability of composites reach the highest value at 4 wt% Si69-MOSW. The composite with MOSW addtion had a higher retention rate after ultraviolet irradiation and the MOSW could improve the anti-ultraviolet aging property of rubber matrix. The modified MOSW can effectively improve the oxygen index and the flame retardant grade of rubber composites.

为研究川西小黄菊茎的化学成分,利用溶剂提取法,半制备高效液相色谱法和正、反相硅胶柱层析法对其乙醇提取物进行了分离纯化,并根据其理化性质和波谱数据进行了结构鉴定.结果表明:从川西小黄菊乙醇提取物中分离得到了18个化合物,分别鉴定为对羟基苯甲酸(1)、1,2,4-苯三酚(2)、原儿茶酸(3)、反式肉桂酸(4)、反式对羟基肉桂酸(5)、反式邻羟基肉桂酸(6)、反式咖啡酸(7)、反式阿魏酸(8)、反式咖啡酸乙酯(9)、香豆素(10)、7-羟基香豆素(11)、6,7-二羟基香豆素(12)、(9Z,11E)-13-氧代-9,11-十八碳二烯酸(13)、绿原酸(14)、绿原酸甲酯(15)、松脂素-β-D-吡喃葡萄糖苷(16)、表松脂素4-O-吡喃葡萄糖苷(17)、表松脂素4′-O-吡喃葡萄糖苷(18),除化合物10以外,其余化合物均为首次从该植物中分离得到.

Calcium carbonate whiskers were modified by stearic acid ,and the modified whiskers were dispersed in a liquid by ultrasonic technology .Natural rubber latex (NRL)/calcium carbonate whiskers medical composites with environmental green and high performance were developed by blending the modified whiskers dispersion liquid and natural rubber latex .The morphology ,mechanical properties ,antibacterial performance and themalstability properties of the composites were investigated .The results show that modified whiskers have good compatibility with NRL matrix .The incorporation of modified whiskers into rubber matrix leads to a betterment in the over-all properties of the composites .When modified whiskers loading of 5wt%,all the performance of composites achieve optimum results .

将超声分散后的硅烷偶联剂3-氨丙基三乙氧基硅烷改性碱式硫酸镁晶须(KH550-MgOSW)分散液加入天然胶乳(NR)中,对其进行补强,制得绿色环保高性能的KH550-MgOSW/NR复合材料.系统研究了KH550-MgOSW/NR复合材料的力学性能、阻燃性能及热稳定性能.结果表明,用KH550改性后的MgOSW与橡胶基体具有很好的相容性.KH550-MgOSW/NR复合材料的力学性能、阻燃性能及热稳定性能均比纯胶有所提高.当KH550-MgOSW与NR质量比为4％时,KH550-MgOSW/NR复合材料的各项性能均达到最佳,300％定伸应力、拉伸强度、撕裂强度、断裂伸长率、交联密度比纯胶胶膜分别提高了25.0％、36.8％、37.3％、11.4％、44.2％,垂直燃烧等级由FV-1提高到了FV-0级,比纯胶的起始热降解温度(T0)、最大热降解温度(Tp)和终止热降解温度(Tf)分别提高了6.2℃、5.2℃和4.1℃.

Abstract Tetra-needle-like zinc oxide whiskers (T-ZnOw) were modified by Si69, and natural rubber (NR)/Si69-T-ZnOw composites were developed by latex-compounding techniques. The mechanical properties, morphology, cross-link density, and thermogravimetry of the composites were investigated. The results show that the tetra-needles of T-ZnOw tightly insert into the rubber matrix. T-ZnOw, which have a special four-dimensional structure, act as a skeleton in the rubber matrix. In comparison with the host NR, the mechanical properties, cross-link density, and thermostability of the resulting composites were significantly improved at Si69-T-ZnOw loadings of 4 wt%. During the thermal decomposition, various characteristic temperatures of the NR/Si69-T-ZnOw composites increase 5–9°C over those of the pure NR. The NR/Si69-T-ZnOw composites have great potential to manufacture medical protective products with high performances.

The Tetra-Needle-like zinc oxide whiskers (T-ZnOw) were modified by stearic acid, and Natural rubber/Stearic acid-T-ZnOw medical antibacterial composites were prepared by blending the Stearic acid-T-ZnOw with natural rubber latex. The morphology, mechanical properties, thermal stability, antibacterial property and water absorption of composites were investigated. The results show that the incorpation of Stearic acid-T-ZnOw into rubber matrix leads to a significantly betterment in the over-all properties of composites when the Stearic acid-T-ZnOw loading is less than 6%. The Stearic acid-T-ZnOw act as a skeleton in the rubber matrix, with its tetra-needles tightly inserting into rubber matrix. It plays an important role in improving the performance of natural rubber. When in nitrogen atmosphere loading of 5 wt%, all the performance of composite achieve optimum results. The Natural rubber/Stearic acid-T-ZnOw has great prospects in producing medical products with greens environmental protection and high performance.