N/S-Doped Hierarchical Porous Bamboo Carbon Fibers with Ultra-Large Surface Area and Highly Exposed Active Sites for Flexible Zinc-Air Battery

Facile mass transport channel and accessible active sites are crucial for binder-free air electrode catalysts in rechargeable flexible zinc-air battery(ZAB).Herein,a ZnS/NH3 dual-assisted pyrolysis strategy is proposed to prepare N/S-doped hierarchical porous bamboo carbon cloth(HP-NS-BCC)as binder-free air electrode catalyst for ZAB.BCC fabric with abundant micropores is firstly used as flexible carbon support to facilitate the heteroatom-doping and construct the hierarchical porous structure.ZnS nanospheres and NH3 activization together facilitate the electronic modulation of carbon matrix by N/S-doping and optimize the macro/meso/micropores structure of carbon fibers.Benefiting from the highly-exposed N/S-induced sites with enhanced intrinsic activity,the optimized mass transport of biocarbon fibers,as well as the ultra-large specific surface area of 2436.1 m^(2)·g^(-1),the resultant HP-NS-BCC catalyst exhibits improved kinetics for oxygen reduction/evolution reaction.When applied to rechargeable aqueous ZABs,it achieves a significant peak power density of 249.1 mW·cm^(-2).As binder-free air electrode catalyst,the flexible ZAB also displays stable cycling over 500 cycles with a minimal voltage gap of 0.42 V,showcasing promising applications in flexible electronic devices.

Offgas Analysis and Pyrolysis Mechanism of Activated Carbon from Bamboo Sawdust by Chemical Activation With KOH

Bamboo sawdust was used as the precursor for the multipurpose use of waste. Offgases released during the activation process of bamboo by KOH were investigated quantitatively and qualitatively by a gas analyzer. TG/DTG curves during the pyrolysis process with different impregnation weight ratios （KOH to bamboo） were obtained by a thermogravimetric analyzer. Pyrolysis mechanism of bamboo was proposed. The results showed that the offgases were composed of CO, NO, SO2 and hydrocarbon with the concentration of 1 372, 37, 86, 215 mg/L, respectively. Thermogravimetric analysis indicated that the pyrolytic process mainly experienced two steps. The first was the low temperature activation step （lower than 300 ℃）, which was the pre-activation and induction period. The second was the high temperature activation step（higher than 550 ℃）, which was a radial activation followed by pore production. The second process was the key to control the pore distribution of the final product.

Diurnal and seasonal variations in carbon fluxes in bamboo forests during the growing season in Zhejiang province, China

Bamboo forest is an important forest type in subtropical China and is characterized by fast growth and high carbon sequestration capacity. However, the dynamics of carbon fluxes during the fast growing period of bamboo shoots and their correlation with environment factors are poorly understood. We measured carbon dioxide exchange and climate variables using open-path eddy covariance methods during the 2011 growing season in a Moso bamboo forest(MB, Phyllostchys edulis) and a Lei bamboo forest(LB, Phyllostachys violascens) in Zhejiang province,China. The bamboo forests were carbon sinks during the growing season. The minimum diurnal net ecosystem exchange(NEE) at MB and LB sites were-0.64 and-0.66 mg C m^(-2) s^(-1), respectively. The minimum monthly NEE, ecosystem respiration(RE), and gross ecosystem exchange(GEE) were-99.3 ± 4.03, 76.2 ±2.46, and^(-1)91.5 ± 4.98 g C m^(-2) month^(-1), respectively,at MB site, compared with-31.8 ± 3.44, 70.4 ± 1.41,and^(-1)57.9 ± 4.86 g C m^(-2) month^(-1), respectively, at LB site. Maximum RE was 92.1 ± 1.32 g C m^(-2) month^(-1) at MB site and 151.0 ± 2.38 g C m^(-2) month^(-1) at LB site.Key control factors varied by month during the growing season, but across the whole growing season, NEE and GEE at both sites showed similar trends in sensitivities to photosynthetic active radiation and vapor pressure deficit,and air temperature had the strongest correlation with RE at both sites. Carbon fluxes at LB site were more sensitive to soil water content compared to those at MB site. Both onyear(years when many new shoots are produced) and offyear(years when none or few new shoots are produced)should be studied in bamboo forests to better understand their role in global carbon cycling.

Sorption Characteristics for Multiple Adsorption of Heavy Metal Ions Using Activated Carbon from Nigerian Bamboo

Sorption characteristics of multiple adsorption of six heavy metal ions often found in refinery waste waters using activated carbon from Nigerian bamboo was investigated. The bamboo was cut, washed and dried. It was carbonized between 350℃ - 500℃, and activated at 800℃ using nitric acid. Simultaneous batch adsorption of different heavy metal ions (Cd2+, Ni2+, Pb2+, Cr3+, Cu2+ and Zn2+) in same aqueous solution using activated carbon from Nigerian bamboo was carried out. The adsorption process had a better fit for the Freundlich, Temkin isotherm and Dubinin-Radushke-vich (DRK) isotherm models but could not fit well into Langmuir isotherm. Adsorption isotherms showed that there is competition among various metals for adsorption sites on Nigerian bamboo. The DRK model was used to determine the nature of the sorption process and was found to be physical and chemical, with sorption energy of metal ions ranging from (7 - 10 kJ/mol). The adsorption of Cd2+, Zn2+, Pb2+ and Ni2+ ions was chemisorptions and that of Cu2+ and Cr3+ ions was cooperative adsorption. Therefore, this study revealed that Nigerian bamboo can serve as a good source of activated carbon with multiple and simultaneous metalions—removing potentials and may serve as a better replacement for commercial activated carbons in applications that warrant their use.

Simulation of Tensile Behaviors of Bamboo-like Carbon Nanotubes Based on Molecular Structural Mechanics Approach Combining with Finite Element Analysis

A molecular structural mechanics approach combining with finite element analysis(MSM/FEA) was applied to study the microstructure and tensile behaviors of bamboo-like carbon nanotubes(BCNTs). The mathematical model of tensile behaviors of BCNTs was established based on molecular structural mechanics theory. The deformations of BCNTs, with different diameters and compartments set based on the experimental investigation on BCNT structures synthesized by chemical vapor depositon, under tensile load, were analyzed with ANSYS programmed. Results show that the BCNTs have good tensile properties, and those Young's modulus can reach 0.84 Tpa. Through the analysis, it can be found that the Young's modulus of BCNTs depends on the diameters and the length of compartment, which is in good agreement with our experimental tests for the tensile performances of individual BCNT.

Synthesis of bamboo-like carbon nanotubes by ethanol catalytic combustion technique

Bamboo-like carbon nanotubes were synthesized by ethanol catalytic combustion (ECC) technique with combustion method. Copper plate was employed as substrate, ethanol as carbon source, and iron chloride as catalyst precursor. The as-grown black powder was characterized by means of scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that the thinner bamboo-like carbon nanotubes have a relatively good structure that the compartment layers are more regular, while the thicker carbon nanotubes have a relatively irregular bamboo-like structure; the proposed method is simple to synthesize bamboo-like carbon nanotubes and has some advantages, such as flexible synthesis conditions, simple setup, and environment-friendly.

Synthesis of Nitrogen Incorporated Carbon Nanotubes with Different Diameters by Catalytic Pyrolysis of Butylamine

Bamboo-like nitrogen-doped carbon（CNx） nanotubes were synthesized by chemical vapor deposition （CVD） at a high reaction temperature of 600―900 °C. The butylamine and Fe/SBA-15 molecular sieve have been used as precursor and catalyst, respectively. Transmission electron microscopy（TEM） and high resolution transmission electron microscopy（HRTEM） observations show that the outer diameter and wall thickness as well as the inner diameter were increased with increasing reaction temperature in a temperature range of 600―800 °C. A synergism mechanism of the growth through bulk diffusion and the competitive growth through surface diffusion functions during the synthesis of CNx nanotubes was proposed.

Acidulation and Regeneration of Bamboo Derived Sorbents for Gas Phase Adsorption of Elemental Mercury

This paper presents results that illustrate the recycling of a bamboo derived sorbent used for the capture of elemental mercury (Hg0). The bamboo derived sorbent used is essentially a HCl functionalized activated carbon prepared from carbonization and CO2 activation of raw bamboo, that could potentially provide an alternative way to existing methods in removing mercury from flue gases from coal-fired plants. In this study, the bamboo derived sorbents were tested in a batch test using a mercury permeation tube as the source and nitrogen as a carrier gas. The recycling or regeneration of an activated carbon is an important issue to address from a coal-fired power plant point of view, and an attempt has been made to test the behavior of bamboo derived sorbents with various treatments including carbonized, carbonized-activated, carbonized-activated-acidulated, and then a follow-up recycled run after sample treatments in gas phase. From the study, it was found that bamboo derived activated carbon can be successfully acidulated using various normalities of HCl where weak solutions can be very effective in functionalizing the surface of the sorbent and capturing mercury. In order to recycle and reuse bamboo derived sorbents, stronger normalities of HCl would be desired.

A Study on the Effects of Carrier Gases on the Structure and Morphology of Carbon Nanotubes Prepared by Pyrolysis of Ferrocene and C_2H_2 Mixture

Carbon nanotubes （CNTs） were prepared using different carrier gases, with ferrocene as the catalyst precusor and acetylene as the carbon source. The effects of ammonia and nitrogen as carrier gases on the structure and morphology of CNTs were investigated. Transmission electron microscope （TEM）, high-resolution electron microscope （HRTEM）, scanning electron microscope （SEM） and X-ray diffraction （XRD） were employed to characterize the products and the catalyst. Experiment results show that the CNTs grown in N2 gas exhibited cylindrical and tubular structure, while a bamboo-like structure was observed for the CNTs grown in NH3 gas. Moreover, vertically aligned CNTs were obtained on an A12O3 disk when NH3 was used as the carrier gas. The carrier gas also exerted influence on the shape of the catalyst. Based on the theory of active centers of catalysis and combined with the particle shape of the catalyst, a growth model for the vertically aligned CNTs on the substrate is given.

原竹龙骨住宅全生命周期碳排放研究

为加速提升农村建筑节能设计水平,加快实现建筑节能减排目标,提出原竹龙骨住宅碳排放计量模型,并进行全生命周期碳排放研究。在项目物化阶段,使用BIM技术建立建筑信息模型,结合碳排放系数法计算碳排放量;在运行阶段,采用eQUEST能耗模拟软件进行能耗分析,计算住宅全年能耗量。以项目实例为研究对象,计算项目各阶段碳排放量。结果表明:在原竹龙骨住宅全生命周期的5个阶段中,运行阶段碳排放量比重最大,物化阶段中建材生产阶段所占碳排放量比重最大,以实际客观数据验证了模型的可靠性。

基于数字图像相关技术的碳化重组竹轨枕受弯特征分析

重组竹材具有负碳属性,经碳化后替代传统材料轨枕具有很大潜力,但针对重组竹轨枕的研究缺少足尺试验。本文设计了采用两种厚度排布方式胶合的碳化重组竹轨枕,使用数字图像相关(Digital Image Correlation,DIC)技术研究竹轨枕在三点抗弯和四点抗弯试验下的轨枕挠度、裂纹特性以及破坏形式。结果表明:碳化重组竹轨枕的极限承载力最高可达292.445 kN (三点抗弯)和414.525 kN(四点抗弯),远高于混凝土轨枕和木枕,抗弯刚度和延性介于混凝土轨枕和木枕之间。厚度排布方式对碳化重组竹轨枕的极限承载力和破坏形式影响较小,但会直接影响轨枕的层间裂纹和断裂位置。碳化重组竹轨枕受弯过程均处于弹性状态,达到极限承载力后发生断裂,其破坏形式为沿着或靠近中性层的胶合面处层间剪切破坏。在三点抗弯试验中,竹轨枕沿着主裂纹方向断裂;在四点抗弯试验中,沿着或靠近枕中截面中性层位置的裂纹断裂。碳化重组竹轨枕的极限承载力、抗弯刚度和延性完全满足铁路轨枕设计要求,可应用于重载铁路和客货共线铁路正线有砟轨道。

安吉竹林碳汇项目的实践、成效与启示

【目的】该研究旨在探讨安吉县如何通过竹林碳汇项目实施,促进地方绿色发展,同时提高经济和生态双重效益。【方法】采用案例分析法,结合安吉县竹林碳汇项目实施过程和成效,通过描述性统计和比较分析方法,评估项目对生态保护和社区经济发展的具体影响。【结果】安吉竹林碳汇项目的实施不仅增强了当地的碳吸收能力,每年增加的碳汇量达到5.85 t·hm^(-2),还促进了竹林经济的多元化发展,提高了农民的收入,并通过碳交易实现了可持续的经济效益。【结论】安吉竹林碳汇项目展示了如何通过地方政策和金融创新有效促进生态保护与经济发展,提供了可持续的生态经济发展模式,为其他地区提供了宝贵的参考。

竹材微炭化干燥工艺中液体产物特性分析

在固定床反应器上采用微炭化工艺干燥处理竹材,并对干燥尾气进行冷凝回收,探讨微炭化干燥工艺对竹材干燥冷凝液体产物特性的影响。研究结果表明:竹材于210℃微炭化干燥处理得到冷凝液体主要含有酸、醛、酯、酮和酚类物质。微炭化工艺对竹材干燥液体产物特性有显著影响,210℃时醛类物质质量分数达22.14%,250℃时醇、酚类物质质量分数分别为25.13%、28.33%;升温速率造成酸、醛类物质先增加后减少,10℃/min时最大,分别为67.89%、22.14%,酮类物质变化趋势则相反,20℃/min时最大,为21.35%;随氮气流量增大,酸类物质增加,由51.84%增至81.71%,醛类、酮类物质减少,分别由26.07%、10.95%降至8.36%、2.58%。竹材微炭化干燥液体产物成分与木、竹醋液相似,具有用作植物生长促进剂、土壤改良剂等潜力。

KOH共热法和水热活化法制备多孔竹活性炭的比较

我国竹材资源丰富,以竹废料为原料,制备可用于超级电容器电极材料的竹活性炭,有助于推动竹产业发展,助力国家“双碳”目标实现。在本研究中,分别采用KOH共热和水热处理对竹粉进行活化,并对制备的竹活性炭进行电化学性能、比表面积、表面微观形貌等测试。实验结果表明,KOH共热活化法的最佳条件为炭化温度350℃,活化温度900℃,升温速率2℃/min,碱炭质量比4∶1;制备的活性炭比表面积为3 299 m2/g, 0.5 A/g电流密度下的比电容为287.8 F/g, 5 000次充放电测试后,电容保持率为95%~105%。水热活化法的最佳条件为KOH质量分数20%,反应温度150℃,反应时间12 h,制备的活性炭比表面积为192.91 m2/g, 0.5 A/g电流密度下的比电容为170.4 F/g,电容保持率为88.89%。2种方法制备的活性炭孔径结构都是以微孔为主,中孔混合分布,含有少量大孔;2种活性炭均含有双层或多层石墨烯结构,但水热活化法制备的活性炭石墨化程度更高,制备条件更温和。研究结果既可为超级电容器用活性炭的研究提供了理论思路,也有效地扩展了竹材的应用领域。

新型CFRP网格-重组竹复合板力学试验研究

为提高重组竹的力学性能并减轻其各向异性缺陷,设计了一种新型CFRP网格-重组竹复合板(CBCP).分别对8组CBCP拉伸试样和18组CBCP拉拔试样进行单轴拉伸试验和拉拔试验,以分析其力学行为并评估复合方法的影响.选择3个相似的构成模型对拉拔试样的黏结应力-滑移曲线进行拟合,根据试验结果确定CFRP网格和重组竹的临界锚固长度及计算方法,并分析讨论了CFRP层数、横向CFRP束特性和锚固长度对CFRP网格与重组竹黏结性能的影响.结果表明,复合CFRP网格可使重组竹的顺纹和横纹抗拉强度分别提高35.77%和135.20%,从而改善了重组竹的各向异性缺陷.增加网格层数和间距可提高CBCP的拉伸性能.随着锚固长度的增加,平均界面黏结强度呈幂函数递减,而峰值载荷滑移则线性递减.

竹皮活性炭对工业废水中高浓度Cr(Ⅵ)的吸附

以竹皮废料为原料,采用水蒸气活化法制备活性炭,用于吸附水中的高浓度Cr(Ⅵ)离子并探究其吸附性能及吸附机理。通过BET、SEM、FTIR、pH及等电点测定对其微观物理形貌和表面化学性质进行了表征。结果表明,制得的活性炭比表面积高达1 068 cm^(2)·g^(-1),总孔容达0.55 cm^(3)·g^(-1)、微孔比例达72.7%、平均孔径为1.01 nm,主要含有羟基、羰基等含氧官能团。单因素吸附实验发现,对于质量浓度为150 mg·L^(-1)的Cr(Ⅵ)在活性炭用量1.2 g·L^(-1)、pH为2时吸附效果最佳,吸附去除率达99.7%,残留质量浓度符合国家标准。推测吸附机理为活性炭表面官能团质子化、活性炭与铬离子之间静电吸引、Cr(Ⅵ)表面还原、Cr(Ⅲ)的吸附或释放。

木竹产品碳足迹评价研究进展

气候变化是全球治理的一个重要方面,评估人类活动引起的温室气体排放量是应对气候变化的基础性工作,受到世界各国政府、科研机构和企业广泛关注。随着我国“碳达峰”“碳中和”(简称“双碳”)目标的提出以及相关政策的落地实施,碳足迹作为温室气体排放测度指标,其重要性日益凸显。开展木竹产品碳足迹评价是我国木竹加工企业落实国家“双碳”目标的核心工作,对木竹产业低碳高质量发展亦具有重要意义。本文全面分析锯材、改性材、人造板及其制品、结构用集成材和胶合木等主要木竹产品碳足迹评价的研究现状,以及碳足迹评价方法的研究进展。目前,生命周期评价法是国际主流的碳足迹评价方法,依据的标准主要为ISO/TS 14067、GHG Protocol和PAS 2050;在木竹产品中储存的生物碳及其延迟碳排放效应的评估方法,以及计入产品碳足迹评价结果的形式等方面尚未形成国际共识;因不同国家木竹加工技术水平和能源结构有所不同,同一类别产品碳足迹差异显著。此外,不同科研人员采用的评价标准和研究假设等各异,导致同一产品碳足迹评价结果可比性不强。未来应:1)研制木竹产品延迟碳排放效应的评估方法,科学量化木竹产品对应对气候变化的积极贡献;2)制定适于木竹产品碳足迹评价国际统一的产品种类规则,进一步增强碳足迹核算结果的可比性,推动木竹产品碳足迹评价结果国际互认;3)建立木竹产品全生命周期回溯跟踪体系,助力木竹产品全生命周期碳足迹评价工作的顺利开展;4)构建契合我国木竹产业特点全国统一的碳排放因子数据库,为准确计量木竹产品碳足迹提供数据支撑。

生物炭对毛竹林土壤有机碳组分及碳库管理指数的影响

为探究不同生物炭施用量对毛竹林土壤有机碳组分及碳库管理指数的影响,本研究以广西桂林漓江上游毛竹林土壤为研究对象,以毛竹废弃物高温热解制备的生物炭为供试材料,通过一年野外施用试验,探究不同生物炭施用量下(0(CK)、10 t·hm^(-2)(BC1)、20 t·hm^(-2)(BC2)、40 t·hm^(-2)(BC4))毛竹林土壤有机碳活性组分和土壤碳库管理指数变化特征,分析环境因素对其影响。结果表明:与对照(CK)相比,高添加量生物炭(BC4)后土壤pH值、速效磷、速效钾、铵态氮、可溶性有机氮、微生物量氮等含量显著提高,但土壤全磷含量显著降低(P<0.05)。生物炭对总有机碳、易氧化有机碳、颗粒有机碳及碳库管理指数等有显著的促进作用,均在生物炭施用量为40 t·hm^(-2)时达到最大值。相关分析表明,土壤碳库管理指数与pH、NH_(4)^(+)-N、EOC、POC均呈极显著正相关关系(P<0.01)。路径分析模型表明在生物炭添加下,土壤性质和可利用性养分直接影响活性碳组分,进而影响土壤碳库管理指数。综上所述,毛竹林中施用生物炭是提高土壤质量、促进土壤碳固存及合理利用竹林废弃物的有效手段,其中生物炭添加量为40 t·hm^(-2)的处理效果最优。

5种主要出口竹笋产品碳足迹评估与减排路径分析

【目的】评估竹笋产品碳足迹,挖掘竹笋产品减排潜力,促进产业低碳高质量发展。【方法】基于2022—2023年浙江省杭州市临安区、湖州市安吉县的实地调查数据,对5种不同类型的竹笋出口产品(调味笋、手剥笋、笋干丝、水煮笋、鲜食笋)种植、生产和分销阶段进行碳足迹评估,识别碳排放热点,进行减排路径设计,并基于情景假设计算减排量;结合中国2015—2023年竹笋产品出口情况,估算中国历年竹笋产品出口隐含碳排放与碳排放强度。【结果】①5种竹笋产品的碳足迹从大到小依次为调味笋(1.3874 kg·kg^(-1))、手剥笋(1.0107 kg·kg^(-1))、笋干丝(0.9274 kg·kg^(-1))、水煮笋(0.3249 kg·kg^(-1))、鲜食笋(0.1748 kg·kg^(-1))。碳足迹构成分析结果显示:5种竹笋产品的碳排放热点主要为农资投入、鲜笋运输、鲜笋加工和附加物投入。②2015—2023年中国的竹笋产品出口平均隐含碳排放为18.4820万t,平均碳排放强度为0.9669 t·万元^(-1)。③基于碳排放热点的减排情景设计显示:2023年5种竹笋产品碳足迹平均下降幅度为20.15%。【结论】不同类型的竹笋产品碳足迹差异较大;2015—2023年的竹笋产品出口隐含碳排放呈波动下降趋势;综合隐含碳排放强度呈波动上升趋势;竹笋产品碳排放热点各有差异,通过减排措施,碳足迹有进一步减排的潜力。图2表7参36.

基于CO_(2)活化的竹基多孔炭催化还原Cr(VI)的性能研究

以竹粉为原料、CO_(2)为活化剂制备竹基多孔炭(ZH-100),并用于催化还原Cr(VI)。分析了反应温度、催化剂用量、还原剂甲酸用量、Cr(VI)初始质量浓度对竹基多孔炭催化活性的影响,采用XPS、XRD和交流阻抗测试技术对反应前后的多孔炭进行表征,以揭示其催化还原Cr(VI)的作用机制。结果表明:竹基多孔炭催化还原Cr(VI)的最佳实验条件为Cr(VI)初始质量浓度120 mg/L、温度60℃、ZH-100炭催化剂添加量0.1 g,还原剂甲酸添加量1.5 mL,在该条件下反应10 min,Cr(VI)还原率高达99.44%;重复使用3次后,ZH-100的催化还原能力略有下降,但仍能在30 min内达到99.22%的Cr(VI)还原率。分析发现,Cr(VI)的去除过程包括物理吸附和化学还原,其中以化学还原占主导;催化剂重复使用性能下降原因包括表面官能团消耗、碳微晶排列无序化及阻抗增大,ZH-100对Cr(VI)的催化还原机制为官能团介导和类石墨微晶介导。