Synthesis, characterization and experimental investigation of Cu-BTC as CO2 adsorbent from flue gas

Porous Cu-BTC material was synthesized by the solvothermal method. Powder X-ray diffraction (PXRD) was used to test the phase purity of the synthesized material and investigate its structural stability under the influence of flue gas components. The thermal stability of the material was determined through thermal gravimetric (TG) analysis. Scanning electron microscopy (SEM) was employed to study the microstructure of the material. Cu-BTC was demonstrated not only to have high CO₂ adsorption capacity but also good selectivity of CO₂ over N₂ by means of packed bed tests. The adsorption capacity of Cu-BTC for CO₂ was about 69 mL/g at 22°C. The influence of the main flue gas components on the CO₂ capacity of the material were discussed as well.     

磁黄铁矿和石灰石改性硫磺发泡材料的脱氮除磷性能研究

基于硫磺自养反硝化(SAD)脱氮效率高、除磷效率低及磁黄铁矿自养反硝化(PAD)除磷效率高、脱氮效率低的特点,利用微细粒磁黄铁矿和石灰石与硫磺熔混、发泡得到磁黄铁矿与石灰石改性硫磺发泡材料(PLMSFM).通过批次试验探究磁黄铁矿和发泡剂配比对PLMSFM脱氮除磷的影响,优化得出硫磺∶石灰石∶磁黄铁矿∶碳酸氢钠的质量比...     

Efficient dechlorination of 2,4-dichlorophenol in an aqueous media with a mild pH using a Pd/TiO2NTs/Ti cathode

In this study, palladium-loaded titania nanotubes was fabricated on a titanium plate (Pd/TiO₂NTs/Ti) for efficient electrodechlorination of 2,4-chlorophenol with a mild pH condition. The nature of Pd/TiO₂NTs/Ti electrodes was characterized by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) techniques. The characterization results indicated the generation of Pd⁰ nanoparticles which were evenly dispersed on titania nanotubes arrays on the Pd/TiO₂NTs/Ti surface. An effective degradation efficiency of up to 91% was achieved within 60 min at cathode potential of −0.7 V (vs. SCE) and initial pH of 5.5. The effects of the applied cathode potential and initial pH on the degradation efficiency were studied. A near neutral condition was more favorable since very low and very high pHs were not conducive to the dechlorination process. Furthermore, the intermediates analysis showed that the Pd/TiO₂NTs/Ti electrode could completely remove chlorine from 2, 4-dichlorophenol since only phenol was detected as the byproduct and the concentration of released chlorine ions indicated near-complete dechlorination. This work presents a good alternative technique for eliminating persistent chlorophenols in polluted wastewater without maintaining strong acidic environment.     

坡面尺度上地貌对α生物多样性的影响

为了解地貌在坡面尺度上对α生物多样性的影响,采用主观采样法在陕北吴起县合家沟流域不同地貌部位进行了样地调查.利用SPSS16.0统计软件先后对各地貌部位物种组成及各物种的重要值、地形因子要素间、地形因子和群落α多样性之间分别做了聚类分析、相关分析和多元回归分析.结果表明:(1)地貌部位相似的群落聚类在一起,说明地形因子是影响物种组成、群落结构、生态系统等的重要因素.(2)海拔和坡位,坡向和坡度,地形指数和海拔、坡位、坡形之间的Pearson 相关系数均大于0.8,双尾显著性检验概率小于0.05.(3)影响α生物多样性指标香农-维纳指数的地形因子按重要性从大到小依次是:坡位、坡向、海拔、坡形、坡度、地形指数,进一步分析得出在黄土高原丘陵沟壑区,沟沿线、光照、土壤水分和养分在影响α生物多样性指标上依次递减.(4)通过多元线形回归检验,得出坡位、坡向、坡形、海拔这四个地形因子与群落α生物多样性关系密切,建立的回归模型显著性检验可信度大,与样本数据的拟合度高.各地形因子数据归一处理后的回归方程为:香农-维纳指数=2.417-0.581×坡形-1.333×坡位+1.449×海拔+0.631×坡向.地形地貌特征在黄土丘陵区表现明显,研究它对生物多样性的影响可为该区植被恢复提供参考,但由于调查样地尺度较小,在应用推广上尚待进一步研究.     

Non-biodegradable landfill leachate treatment by combined process of agitation,coagulation, SBR and filtration

This study describes the complete treatment of non-biodegradable landfill leachate by combined treatment processes. The processes consist of agitation as a novel stripping method used to overcome the ammonia toxicity regarding aerobic microorganisms. The NH₃-N removal ratio was 93.9% obtained at pH 11.5 and a gradient velocity (G) 150 s^?1 within a five-hour agitation time. By poly ferric sulphate (PFS) coagulation followed the agitation process; chemical oxygen demand (COD) and biological oxygen demand (BOD₅) were removed at 70.6% and 49.4%, respectively at an optimum dose of 1200 mg L^?1 at pH 5.0. The biodegradable ratio BOD₅/COD was improved from 0.18 to 0.31 during pretreatment step by agitation and PFS coagulation. Thereafter, the effluent was diluted with sewage at a different ratio before it was subjected to sequencing batch reactor (SBR) treatment. Up to 93.3% BOD₅, 95.5% COD and 98.1% NH₃-N removal were achieved by SBR operated under anoxic–aerobic–anoxic conditions. The filtration process was carried out using sand and carbon as a dual filter media as polishing process. The final effluent concentration of COD, BOD₅, suspended solid (SS), NH₃-N and total organic carbon (TOC) were 72.4 mg L^?1, 22.8 mg L^?1, 24.2 mg L^?1, 18.4 mg L^?1 and 50.8 mg L^?1 respectively, which met the discharge standard. The results indicated that a combined process of agitation-coagulation-SBR and filtration effectively eliminated pollutant loading from landfill leachate.     

Application of biochar in advanced oxidation processes: supportive,adsorptive, and catalytic role

Environmental Science and Pollution Research - The advanced oxidation processes (AOPs), especially sulphate radical (SO4•−)–based AOPs (SR-AOPs), have been considered more...     

FeS-Fe0纳米复合材料活化过硫酸盐降解双酚S的研究

双酚S(BPS)是一种新兴的内分泌干扰物,在环境中广泛存在,并对自然环境和人体健康有严重危害。制备了FeS-Fe⁰纳米复合材料作为催化剂,明确了FeS-Fe⁰纳米复合材料活化PS体系(FeS-Fe⁰/PS体系)的反应条件对去除BPS的影响,包括材料中FeS与Fe⁰摩尔比、材料投加量、PS浓度、溶液初始pH值等,并应用X射线衍射分析、X射线光电子能谱分析等技术表征该复合材料,通过反应体系对比实验、Fe离子溶出实验、PS的消耗实验、猝灭实验、电子顺磁共振波谱检测,探究了FeS-Fe⁰纳米复合材料的活化机理。实验结果表明:FeS-Fe⁰/PS体系降解BPS的最优条件为溶液初始pH=3、FeS与Fe⁰摩尔比1∶25、材料投加量0.10 g/L、PS浓度1.0 mM;FeS-Fe⁰/PS体系中产生的硫酸根自由基(SO₄^·-)和羟基自由基(HO·)可降解BPS,且HO·占主导作用;FeS-Fe⁰纳米复合材料表面的FeS促进了铁离子的溶出和循环,因此其活化能力优于纳米零价铁。     

低效低质人工林优化改造后林下植被多样性研究

采用样地调查法,对经过人工优化改造的陕西吴起县城周边的低效低质林,选取了其中的11种改造模式（即人工林林分）及1块天然次生林,进行了林下植被多样性的研究。结果表明：12个样地共调查到55种植物,各样地林下植物种有11-23种;阿尔泰狗娃花（altaicus（Willd．）Novopokr．）、达呼里胡枝子（davuriea（Laxm．JSehi月d1．）、赖草（JPc口li”淞（GeorgOTzveL）、针茅（capillataLinn．）、毛连蒿（vestitaWall．exBess．）和委陵菜（chinensisSer．）是最常见的种。而赖草、毛连蒿、达呼里胡枝子、华北米蒿（giraldiiPamp．）、茵陈蒿（capillarisThunb．）、艾蒿（1avandulaefolia DC．）是改造后人工林林下重要值最大的优势种,植物偶见种也较多;不同样地林下植物多样性指数差异显著;物种多样性指数Gleason指数和种间相遇机率（PIE）指数变化趋势基本一致,Simpsom指数、Pielou均匀度指数变化趋势与前两者相反,Shannon—Wiener指数变化趋势不明显。分析表明：人工林林下植被多样性较之天然林要差,其多样性受人工林林分密度、林龄及林分组成等影响。     

CO2 adsorption performance of ZIF-7 and its endurance in flue gas components

Porous ZIF-7 with the sodalite （SOD） cage structure （ZIF, Zeolitic imidazolate framework） were synthesized by the solvothermal method. Synthesized material was characterized by powder X-ray diffraction （PXRD）, thermal gravity （TG）, scanning electron micro- scopy （SEM） and Na adsorption analysis. ZIF-8 with the SOD structure and a littl larger pore window was synthesized in a similar way and was characterized for comparisons. Thermal stability and structural stability of ZIF-7 were tested through PXRD analysis, and the capability of the material for CO2 capture from simulated flue gas was investigated through physical adsorption method. The results showed that CO： adsorption capacity on ZIF-7 was about 48 mL. gl while the capacity on ZIF-8 was about 18mg.g-1 （at 12C and 0.98 P/Po relative pressure）. Furthermore, the impact of flue gas components on adsorption capacity of ZIF-7 and the selectivity of CO2 against N2 on ZIF-7 was also investigated in this work     

兰州市城市植被生态系统服务功能价值研究

采用Costanza等人的生态系统服务评价方法,对兰州市区植被生态系统的调节气候、固碳释氧、涵养水源、净化环境和减弱噪声等四项服务功能进行评估.结果表明,2000年,兰州市植被生态系统服务功能价值为1.64×109元.同时,城市植被生态系统各生态服务功能价值大小依次为:固碳释氧、调节气候、净化环境、减弱噪声、涵养水源.净化环境和减弱噪声是兰州市下阶段城市植被规划设计中需要重点保障的生态系统服务功能.