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阿司匹林生产过程中会产生大量的粉末状废弃活性炭,对环境造成了较大的影响。提出了不外加活化气体的微波加热一步再生法再生废弃活性炭,使之循环利用。通过试验考察了再生温度、再生时间和物料厚度等因素对再生活性炭吸附性能和得率的影响。在再生温度700℃、再生时间10 min和物料厚度20 mm的优化条件下,亚甲基蓝吸附量为180 mg/g,再生活性炭的得率为40.875%,与常规方法再生药用活性炭相比,降低了再生温度,再生时间缩短了50%左右。此时再生活性炭的比表面积为1 296 m~2/g,平均孔径为3.016nm,适合于吸附亚甲基蓝,总孔体积为0.977 4 m L/g,其中微孔占47.81%,表明微孔和中孔都较为发达。扫描电镜和傅里叶变换红外光谱图分析表明,活性炭孔隙和表面性质得到了有效的再生恢复。微波一步再生法避免了通入活化气体而导致大量粉末活性炭被带走的问题,并且该方法具有速度快、效率高等优势。 相似文献
214.
Yuepeng Zhou Xiaoping Shi Dengyan Ji Xianlei Ma Satish Chand 《Natural resources forum》2019,43(2):95-110
The decentralization of property rights is the focus of the forest tenure reforms in several developing countries. In China, it was achieved by the launch of a new round of collective forest tenure reform beginning in 2003, which provided farmers with more integrated and secure forestland rights. Drawing on household data collected in Jiangxi province in 2011 and 2013, this paper examines the impacts of households’ recognition of property rights and improved tenure security on forestland rental activities. Our empirical results show that households with higher perceptions of more complete use rights and mortgage rights have a lower probability and intensity of renting‐in land, while households with lower expectations of future forestland redistribution or expropriation are more likely to rent in forestland and more of it. These results imply that the development of a forestland rental market leading to better forest management requires an integrated forestland management approach consisting of decentralization of property rights and village governance. In particular, the central government may further clarify the rights and obligations affiliated to forestland ownership, contractual rights, and management rights; while the village collective may shift from direct intervention in the integrity and security of forestland rights to the supervision and protection of decentralized forestland rights to increase efficiency from the decentralization of property rights. 相似文献
215.
我国人工林生态系统正面临着结构退化、功能降低等问题,迫切需要通过合理的森林管理方案实施有效的管理措施加以改善。本文以湖南省会同县磨哨林场为研究区,应用生态系统过程模型PnET-II和森林景观模型LANDIS-II,采用情景模拟的方式研究未来100年低、中、高强度的采伐措施以及人工更新对森林面积和地上生物量的影响。结果表明:(1)随着采伐强度增加,人工针叶林面积持续减少、森林AGB下降幅度加大;(2)人工更新措施能够使人工针叶林面积保持稳定,促进其AGB积累,有利于人工林更新与生长;(3)对人工林采取中等强度采伐且实施伐后人工更新的管理方案有利于我国南方以杉木(Cunninghamia lanceolata)、马尾松(Pinus massoniana)为主要树种的人工林地区实现森林可持续经营。 相似文献
216.
Ning Liu Jatin Kal Shirong Liu Vanessa Haver Bernard Dell Keith R.J. Smettem Richard J. Harper 《环境科学学报(英文版)》2020,32(4):262-274
Increasing atmospheric CO2 is both leading to climate change and providing a potential fertilisation effect on plant growth. However, southern Australia has also experienced a significant decline in rainfall over the last 30 years, resulting in increased vegetative water stress. To better understand the dynamics and responses of Australian forest ecosystems to drought and elevated CO2, the magnitude and trend in water use efficiency (WUE) of forests, and their response to drought and elevated CO2 from 1982 to 2014 were analysed, using the best available model estimates constrained by observed fluxes from simulations with fixed and time-varying CO2. The ratio of gross primary productivity (GPP) to evapotranspiration (ET) (WUEe) was used to identify the ecosystem scale WUE, while the ratio of GPP to transpiration (Tr) (WUEc) was used as a measure of canopy scale WUE. WUE increased significantly in northern Australia (p < 0.001) for woody savannas (WSA), whereas there was a slight decline in the WUE of evergreen broadleaf forests (EBF) in the southeast and southwest of Australia. The lag of WUEc to drought was consistent and relatively short and stable between biomes (≤3 months), but notably varied for WUEe, with a long time-lag (mean of 10 months). The dissimilar responses of WUEe and WUEc to climate change for different geographical areas result from the different proportion of Tr in ET. CO2 fertilization and a wetter climate enhanced WUE in northern Australia, whereas drought offset the CO2 fertilization effect in southern Australia. 相似文献
217.
Photo-responsive adsorption-photocatalysis nanocomposites are generally used in water and wastewater decontamination; however, the prolonged adsorption capacity of composites and the role of adsorption in concomitant photocatalysis are typically neglected. These composites can be regenerated under light irradiation as their adsorption capacity decreases. Herein, a novel adsorption-photocatalysis bifunctional nanocomposite, Bi-doped TiO2 supported on powdered activated carbon (Bi2O3/TiO2/PAC), was prepared using the sol-impregnation-hydrothermal procedure. Bi2O3/TiO2/PAC with a secondary calcination temperature of 700°C under a nitrogen atmosphere was selected for maximum adsorption capacity on Methyl Orange (MO). The composite displayed an excellent adsorption capacity and was easily separated and recycled. The results demonstrate that 71.2% photocatalytic regeneration efficiency could be attained under visible light irradiation for 1 hr at an intensity of 750?W/m2 and pH 7. Characterization of the as-prepared Bi2O3/TiO2/PAC nanocomposite (700°C) indicates that it possesses a highly specific surface area and great optical properties, showing bifunctional adsorption-photocatalysis characteristics. The p-n heterojunction of the composite played a dominant role in the photocatalytic regeneration process, and effective degradation of MO could be achieved along with composite regeneration. 相似文献
218.
针对污水厂尾水深度脱氮问题,以某地产天然沸石为原料,采用水热合成法制备了纯度较高、晶型规整、大小均一、吸附量大的A型分子筛.系统考察了其对氨氮的吸附及再生特性,并结合Zeta电位、FTIR以及XRD对其氨氮吸附与再生机理进行了分析.结果表明:准一级和准二级反应动力学均能较好地反映A型分子筛吸附氨氮过程,等温吸附过程符合Langmuir等温吸附模型,对氨氮的最大饱和吸附量为41.68mg/g;吸附饱和的分子筛再生利用方法简便易行,经2mol/L NaCl溶液解吸后能够恢复其吸附能力,5次吸附-解吸再生率均在95%以上;其吸附与再生过程均为Na+与NH4+的离子交换反应,吸附与再生互为可逆过程.该方法为污水厂深度脱氮提供了一条经济可行的新思路. 相似文献
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220.
This paper provides an overview of the emerging role of Aboriginal people in Sustainable Forest Management (SFM) in Canada over the past decade. The 1996 Royal Commission on Aboriginal Peoples (RCAP) provided guidance and recommendations for improving Aboriginal peoples' position in Canadian society, beginning with strengthening understanding and building relationships between Aboriginal and non-Aboriginal parties. This paper explores the extent to which advances in Aboriginal/non-Aboriginal relationships and Aboriginal forestry have been made as a result of RCAP's call for renewed relationships based on co-existence among nations. Such changes have begun to alter the context in which Aboriginal/non-Aboriginal relationships exist with respect to SFM. While governments themselves have generally not demonstrated the leadership called for by RCAP in taking up these challenges, industry and other partners are demonstrating some improvements. A degree of progress has been achieved in terms of lands and resources, particularly with co-management-type arrangements, but a fundamental re-structuring needed to reflect nation-to-nation relationships has not yet occurred. Other factors related to increasing Aboriginal participation in SFM, such as the recognition of Aboriginal and treaty rights, are also highlighted, along with suggestions for moving Aboriginal peoples' SFM agenda forward in the coming years. 相似文献