Preparation of ultrahigh-surface-area sludge biopolymers-based carbon using alkali treatment for organic matters recovery coupled to catalytic pyrolysis

In this work, we employed waste activated sludge (WAS) as carbon source to prepare ultrahigh specific surface area (SSA) biopolymers-based carbons (BBCs) through alkali (KOH) treatment coupled to pyrolysis strategy. Before the pyrolysis process, the involvement of KOH made a great recovery of soluble biopolymers from WAS, resulting in highly-efficient catalytic pyrolysis. The Brunner-Emmett-Teller and pore volume of BBCs prepared at 800°C (BBC₈₀₀) reached the maximum at 2633.89 m²·g^?1 and 2.919 m³·g^?1, respectively. X-ray photoelectron spectroscopy suggested that aromatic carbon in the form of C=C was the dominant fraction of C element in BBCs. The N element in BBCs were composed of pyrrolic nitrogen and pyridinic nitrogen at 700°C, while a new graphitic nitrogen appeared over 800°C. As a refractory pollutant of wastewater treatment plants, tetracycline (TC) was selected to evaluate adsorption performance of BBCs. The adsorption behavior of BBCs towards TC was conformed to the pseudo-second-order kinetic and the Langmuir models, signifying that chemisorption of monolayers was dominant in TC adsorption. The adsorption capacity of BBC₈₀₀ reached the maximum at 877.19 mg·g^?1 for 90 min at 298 K. Thermodynamic analysis indicated that the adsorption process was endothermic and spontaneous. Hydrogen bonding and π-π stacking interaction were mainly responsible for TC adsorption, and interfacial diffusion was the main rate-control step in adsorption process. The presence of soluble microbial products (SMPs) enhanced TC removal. This work provided a novel strategy to prepare bio-carbon with ultrahigh SSA using WAS for highly-efficient removal of organic pollutants.     

杭州湾地区核电厂大气中尺度扩散特征研究

采用拉格朗日随机粒子扩散模式和当地实际气象资料,模拟以秦山核电厂为排放源的大气污染物在杭州湾地区的中尺度扩散情况.对代表性年份(1996)各季中月整4个月模拟结果的分析表明,各季平均扩散输送特征受季节变化和当地海陆地形分布的影响明显.春夏季(4,7月)以溯杭州湾往偏西和偏北内陆方向的输送为主,冬秋季(1,10月)主要为向杭州湾南岸及外海诸方向的输送.区域平均扩散能力以春季(4月)为强,秋季(10月)较弱.污染物扩散输送出模拟区域的平均时间春季略小于15h,秋季约24h,冬夏季约20h.     

低层大气湍流度的参数化估算

水平和垂直风向的标准差是划分大气扩散类型的有效参数.本文提出了一种合理估算σ_θ和σ_(?)的参数化方法.在分析中无因次湍流速度的标准差σ_v/u_*和σ_w/u_*按近年来边界层大气湍流研究所得到的规律确定,无因次风速u/u_*依高度的高低分别接近地面层的风速廓线规律和幂次律推论.结果表明σ_θ和σ_(?)同时依赖于大气稳定度类型、边界层厚度、地面粗糙度和高度.在实用中地面粗糙度可按常规经验确定,大气边界层的稳定度性质和L可按P—T稳定度分类推论,但是边界层高度必须通过与温度廓线有关的信息确定.     

Electricity-driven ammonia oxidation and acetate production in microbial electrosynthesis systems

• MES was constructed for simultaneous ammonia removal and acetate production. • Energy consumption was different for total nitrogen and ammonia nitrogen removal. • Energy consumption for acetate production was about 0.04 kWh/g. • Nitrate accumulation explained the difference of energy consumption. • Transport of ammonia and acetate across the membrane deteriorated the performance. Microbial electrosynthesis (MES) is an emerging technology for producing chemicals, and coupling MES to anodic waste oxidation can simultaneously increase the competitiveness and allow additional functions to be explored. In this study, MES was used for the simultaneous removal of ammonia from synthetic urine and production of acetate from CO₂. Using graphite anode, 83.2%±5.3% ammonia removal and 28.4%±9.9% total nitrogen removal was achieved, with an energy consumption of 1.32 kWh/g N for total nitrogen removal, 0.45 kWh/g N for ammonia nitrogen removal, and 0.044 kWh/g for acetate production. Using boron-doped diamond (BDD) anode, 70.9%±12.1% ammonia removal and 51.5%±11.8% total nitrogen removal was obtained, with an energy consumption of 0.84 kWh/g N for total nitrogen removal, 0.61 kWh/g N for ammonia nitrogen removal, and 0.043 kWh/g for acetate production. A difference in nitrate accumulation explained the difference of total nitrogen removal efficiencies. Transport of ammonia and acetate across the membrane deteriorated the performance of MES. These results are important for the development of novel electricity-driven technologies for chemical production and pollution removal.     

冀中南平原区气溶胶标高变化及估算模型研究

作为反映大气气溶胶垂直分布的重要参量,气溶胶标高被广泛应用于气溶胶反演及模型订正研究中.为研究气溶胶标高时空变化规律并构建其简易计算模型,基于2009～2016年气象站点观测资料及MODIS卫星反演数据,利用Peterson模型及多元回归分析对冀中南平原区气溶胶标高进行了估算分析.研究结果表明:区域气溶胶标高夏季最高,...     

结合脉动测试的金刚宝座塔地震反应分析及震害预测

为了研究内蒙古呼和浩特市慈灯寺金刚宝座塔的抗震性能,测试了金刚宝座上五座小塔的动力特性,并建立数值模型计算结构的动力特性。通过动力特性比较,确定了结构整体等效弹性模量,输入调幅后的三向EL-Centro波计算古塔的地震反应,输出古塔各层应力响应、弹性位移响应、最大层间位移角以及塔底加速度时程。结果表明:中塔的水平剪应力在塔体中部最大,中塔竖向正应力、边塔水平剪应力和竖向正应力在塔体底部最大;层间位移值在塔体顶部最大,中塔和边塔的结构薄弱层分别为4层与顶层以及底层与顶层。慈灯寺塔在8度多遇地震下塔体基本完好,在8度罕遇地震下塔体上部将产生严重破坏。设置金刚宝座降低了各小塔的振动频率,加大了塔体底部的加速度幅值,不利于古塔的抗震性能。     

花生壳活性炭对水溶液中Cr(Ⅵ)的吸附性能

为提高花生壳对Cr(Ⅵ)的吸附性能,采用ZnCl2对花生壳进行改性,制得花生壳活性炭。通过批次吸附实验,考察了花生壳活性炭投加量、pH值、吸附时间等因素对Cr(Ⅵ)的吸附性能影响,同时,对吸附动力学、等温吸附特征和热力学进行了系统研究。结果表明,当吸附剂投加量为0.2 g时,在Cr(VI)初始浓度为20 mg/L、pH值为2.0条件下,吸附反应180 min后,花生壳活性炭对Cr(Ⅵ)的吸附率可维持在94.13%以上。吸附过程符合准二级动力学方程和Langmuir等温吸附模型;由吸附热力学方程计算得到吸附焓变(ΔH)>0,吸附自由能变(ΔG)<0,吸附熵变(ΔS)>0,表明花生壳活性炭对Cr(Ⅵ)的吸附过程是吸热和自发的。     

淮北平原典型农田土壤N2O产生途径及相关功能基因丰度研究

温室气体氧化亚氮(N₂O)已成为全球关注的焦点,全球约60%的人为N₂O排放来自农业土壤.虽然已知微生物硝化和反硝化是土壤N₂O产生的主要过程,但N₂O产生的关键生物学机制以及其调控环境变量之间的相互作用仍然难以预测.本研究选取安徽省亳州市冬、夏两季农田垂向土壤(0～200 cm)为研究对象,通过乙炔抑制法、¹⁵N-¹⁸O同位素示踪技术分别测定了N₂O产生潜势及产生途径,并利用宏基因组测序技术分析不同N₂O产生途径中功能基因的丰度变化以解析农田土壤N₂O产生的微生物机理.结果显示,在空间尺度上,表层土壤(0～20 cm)是N₂O产生热区,其N₂O产生潜势最高,为(0.364±0.048)ng·g^-1·h^-1.硝化和反硝化潜势均在表层土壤达到最高.在时间尺度上,冬季(15℃)是N₂O产...     

落石冲击下多种类型土壤缓冲性能研究

针对现有研究对落石灾害中不同类型土壤中落石的最大冲击力和冲击力变化规律偏差较大的情况,对落石在四种土壤中的冲击力进行研究。通过试验验证SPH-FEM方法在冲击力方面的适用性。采用SPH-FEM模型分析落石在四种土壤中的最大冲击力、冲击力时程曲线规律和在砂土中的冲击力时程曲线公式。分析结果表明:SPH-FEM数值模型能够准确用于研究落石在土层中的最大冲击力和冲击力时程曲线。四种土壤的缓冲性能顺序为砂土、黏土、壤土和黄棕壤。研究得到落石在四种土壤中的最大冲击力与落体直径、冲击速度的关系曲线以及在砂土中的冲击力时程曲线公式。     

黄河三角洲外来入侵物种米草对滩涂昆虫的影响

2005年5,8,10月份对黄河三角洲无棣岔尖、东营市五号桩、小清河口米草分布区与土著植物芦苇分布区的昆虫作了调查,并辅以2003年同期调查资料,结果表明：米草分布区共鉴定出昆虫9种,芦苇分布区鉴定出49种,是米草分布区昆虫种数的5．4倍,米草分布区昆虫种数明显少于芦苇分布区,且优势类群存在很大差异,米草入侵对昆虫的结构、组成与多样性产生了影响。