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391.
Lotaustralin from the root of Rhodiola rosea L was extracted using supercritical carbon dioxide with methanol as modifier. Response surface methodology using Box–Behnken experimental design was utilized to explore parameters for supercritical carbon dioxide extraction. The effects of various values of temperatures (50–70 °C), pressures (200--400 bar), and percentages of methanol modifier (80%–100%) on the extraction yields of lotaustralin were evaluated. Extract identification was performed using high-performance liquid chromatography. The experimental data obtained were fitted to second-order polynomial equations and assessed using analysis of variance. The highest yields predicted from the experiments were 2.05 g kg?1 lotaustralin at the optimal values, i.e. temperature 65 °C, pressure 316 bar, 88% methanol modifier at a flow rate of 0.4 mL min?1, and dynamic extraction time 90 min. 相似文献
392.
Ya Ma Yan Cui Xiaoxi Zuo Shanna Huang Keshui Hu Xin Xiao Junmin Nan 《Waste management (New York, N.Y.)》2014,34(10):1793-1799
A process for reclaiming the materials in spent alkaline zinc manganese dioxide (Zn–Mn) batteries collected from the manufacturers to prepare valuable electrolytic zinc and LiNi0.5Mn1.5O4 materials is presented. After dismantling battery cans, the iron cans, covers, electric rods, organic separator, label, sealing materials, and electrolyte are separated through the washing, magnetic separation, filtrating, and sieving operations. Then, the powder residues react with H2SO4 (2 mol L?1) solution to dissolve zinc under a liquid/solid ratio of 3:1 at room temperature, and subsequently, the electrolytic Zn with purity of ?99.8% is recovered in an electrolytic cell with a cathode efficiency of ?85% under the conditions of 37–40 °C and 300 A m?2. The most of MnO2 and a small quantity of electrolytic MnO2 are recovered from the filtration residue and the electrodeposit on the anode of electrolytic cell, respectively. The recovered manganese oxides are used to synthesize LiNi0.5Mn1.5O4 material of lithium-ion battery. The as-synthesized LiNi0.5Mn1.5O4 discharges 118.3 mAh g?1 capacity and 4.7 V voltage plateau, which is comparable to the sample synthesized using commercial electrolytic MnO2. This process can recover the substances in the spent Zn–Mn batteries and innocuously treat the wastewaters, indicating that it is environmentally acceptable and applicable. 相似文献
393.
394.
2012年4月,黑龙江省第十一次代表大会报告中指出:必须坚持保护环境不动摇,大力加强生态保护.在建设大美龙江上实现新跨越。让青山常在、绿水长流,造福黑龙江,无愧子孙。抓好生态环境保护工程。努力建设大美龙江是社会主义生态文明建设的内在要求、是维护国家生态安全,实现可持续发展的有力保障、是实施富民强省战略部署的有效途径。本文通过对黑龙江省生态文明建设取得成就的梳理,分析黑龙江省生态文明建设过程中存在的问题及问题产生的原因,旨在探讨和提出建设大美龙江的对策建议。 相似文献
395.
本文基于中国"陌生人"社会的社会背景下,采用问卷方式对社会各个层次对地震监测预报信息的需求、认知现状等进行了抽样调查,提出了地震监测预报服务社会信息产品的种类及可行性。 相似文献
396.
397.
Cao Shengwei Fei Yuhong Tian Xia Cui Xiangxiang Zhang Xueqing Yuan Ruoxi Li Yasong 《Environmental science and pollution research international》2021,28(35):48343-48361
Environmental Science and Pollution Research - Identifying sources of nitrate contamination has been a long-term challenge in areas with different land uses. We investigated the biogeochemical... 相似文献
398.
针对黄土高原地区某原油外输干线管道出现的严重内腐蚀穿孔问题,通过化学成分、金相组织、力学性能等方法对管材基本性能进行分析;利用扫描电镜、X射线衍射、细菌测试等方法,开展管道腐蚀原因及机理分析。结果表明:管道材质符合标准规范要求。腐蚀产物外层中含有CaCO_3、SiO_2等沉积物,内层中含有FeS、FeCl_2等腐蚀产物,同时管道中还含有相当数量的SRB、TGB、FB等细菌。因此判定管道的腐蚀是垢下腐蚀和细菌腐蚀共同作用造成的。建议在管道中定期加注杀菌剂,并在易腐蚀部位安装腐蚀监检测设备,实时关注管道腐蚀状况。 相似文献
399.
Algal organic matter (AOM), including extracellular organic matter (EOM) and intracellular organic matter (IOM) from algal blooms, is widely accepted as essential precursors of disinfection byproducts (DBPs). This study evaluated the effect of ozonation or ozone combined with activated carbon (O3-AC) treatment on characteristic alternation and DBP formation with subsequent chlorination of Chlorella sp.. The effects of pH and bromide concentration on DBP formation by ozonation or O3-AC treatment were also investigated. Results showed that the potential formation of DBPs might be attributed to ozonation, but these DBP precursors could be further removed by activated carbon (AC) treatment. Moreover, the formation of target DBPs was controlled at acidic pH by alleviating the reactions between chlorine and AOM. Besides, the bromide substitution factor (BSF) value of trihalomethanes (THMs) from EOM and IOM remained constant after AC treatment. However, THM precursors could be significantly decreased by AC treatment. The above results indicated that O3-AC was a feasible treatment method for algal-impacted water. 相似文献
400.
Yangyang Cui Gen Zhang Wei Wang Yan Shen Xiaoman Zhai Xuefang Wu Renfei Li Bobo Wu Yifeng Xue 《环境科学学报(英文版)》2022,34(4):391-400
The incineration of sacrificial offerings is a significant widely practiced custom that is also a kind of neglected air pollution source in China. Our results showed that the emission factors of particulate matter, SO2, CO, NOx, and VOCs emitted from the incineration of sacrificial offerings with purification systems were reduced by 95%, 19%, 9%, 82%, and 42%, respectively, compared with those without a purification system, revealing a significant effect of the flue gas purification system on reducing particulate matter and gaseous pollutants. The emission level of air pollutants from the incineration of sacrificial offerings remained stable before 2013 and then showed a remarkable decrease after the implementation of China´s Air Pollution Prevention Action Plan in 2013. The emissions of TSP (total suspended particulate), PM10, PM2.5, and NOx in 2009 were 8222, 6106, 5656 and 15,878 ton, respectively, obviously higher than 3434, 2551, 2305 and 8579 ton in 2019. Such trend was affected by both the quantity of incineration and the installation rate of purification systems after the Emission Standard of Air Pollutants for Crematory (GB 13801-2015) issued in China. Distinct spatial distribution of atmospheric pollutants from incineration of sacrificial offerings was found with higher in the east and south of China than the west and north of China, which is proportional to the regional economy and population. The maximum ground-level concentration typically occurred at 0.12-0.2 km from the pollution source, posing potential health risks to people entering and exiting funeral and burial sites and nearby residents. 相似文献