磷石膏废渣对小麦生长及麦田N_2O排放影响与经济环境效益分析

磷化工业产生的大量废渣磷石膏污染环境、占用土地,尚未得到很好的治理和利用。文章研究磷石膏废渣资源化利用,探索其对小麦田氧化亚氮(N_2O)排放以及小麦生长以及产量的影响。结果表明:施用不同量的磷石膏废渣对小麦生长、产量以及麦田N_2O的排放量的影响有所不同。施用磷石膏2 100 kg/hm~2对小麦千粒重以及产量等都有显著影响,可增产达48.11%。同时在整个小麦生长季,与单施有机肥处理相比,施用磷石膏废渣2 100 kg/hm~2可减少麦田N_2O排放量达30.14%,且减排作用具有持续性,在小麦的拔节期、抽穗期以及灌浆期的减排效果尤为显著。与之相比施用磷石膏1050 kg/hm~2的各项效果都比较微弱。研究还表明施用45%复合肥900 kg/hm~2虽然也促进小麦生长,增加小麦产量,但在整个生长季会显著增加N_2O的排放54.70%。在施用磷石膏条件下,小麦的鲜重和产量与麦田N_2O排放呈现显著负相关,与麦田N_2O排放强度呈现显著正相关,即磷石膏在显著促进小麦生长的同时可以显著降低麦田N_2O的排放。以碳交易背景为基础,分析磷石膏减排剂的田经济环境效益,结果表明,施用磷石膏废渣2 100 kg/hm~2,麦田的收入与产出比由1∶9.93提高到1∶17.82,产出增加约79.46%,同时还能够累计减少N_2O的排放达161.71 kg/hm~2。每吨磷石膏废渣可以减少N_2O排放76.48 kg,折合减少CO_2排放22 944 kg,环境收益达到1 140.55元。磷石膏作为减排剂施用,不仅可以减少环境污染,还能促进小麦生长,减少N_2O排放,对发展生态农业并缓解温室效应具有重要的应用价值。     

β环糊精改性聚氨酯基涂料的火安全性与热解动力学分析

为提高膨胀型防火涂料的阻燃性能,以聚氨酯树脂为基料,以聚磷酸铵、尿素为阻燃体系,通过加入不同掺量的钛酸酯偶联剂改性β-环糊精（β-CD）,提高阻燃效果。通过红外光谱仪（FT-IR）、锥形量热仪（CONE）、热重分析仪(TG)、差热扫描量热仪(DSC)等,研究改性β-CD的含量对膨胀型防火涂料的火安全性的影响,使用Coats-Redfern积分法计算涂料的热解动力学。研究结果表明:改性β-CD能有效地提高涂料的阻燃性能,当β-CD为1wt%时拥有最佳阻燃性能,1wt%改性β-CD能够提高涂层的蓄热能力,延缓APP的分解和抑制碳质材料的分解,进而提高涂料的阻燃性能。通过热解动力学拟合曲线得出,1wt%的样品能在253 ℃以后显著提高反应的活化能,提高涂层的阻燃性。     

火电厂烟气脱硫系统运行常见故障分析

为降低火电厂SO<,2>的排放,大部分火电厂采用烟气脱硫技术,在烟气脱硫技术中湿式石灰石/石膏法脱硫应用最为广泛,而脱硫系统的运行可靠性是保证火电厂烟气脱硫效果,减少SO<,2>排放的重要保证.在已投运的火电厂中,脱硫系统运行可能会出现脱硫效率下降,系统堵塞等问题,因此在实际过程中如何处理好此类问题成为保证火电厂脱硫效...     

上海西南郊区PM2．5污染状况研究

研究了上海西南郊区PM2．5（细颗粒物）污染特征,分析了PM2．5与其它污染因子和气象因子相关性,并提出了PM2．5污染控制建议。     

砂土液化对基础隔震结构地震反应的影响分析∗

砂土液化会对结构的地震反应产生不可忽视的影响,这一现象也将对基础隔震结构地震反应规律产生影响。 基于有限元方法,采用 ABAQUS建立了土?隔震结构非线性动力相互作用的整体有限元分析模型,针对不同地基液化情况对基础隔震结构地震反应规律及隔震效果的影响进行了深入分析。结果表明：隔震结构下部桩基础能够有效提高下部地基的抗液化能力,进而保证隔震结构的整体稳定性。总体来看,液化场地上隔震结构的隔震效果及地震反应与输入地震动的特性相关,近场地震作用下液化地基上隔震结构的隔震性能保持良好,而远场强震作用下液化地基上隔震结构的隔震效果降低。同时隔震层产生较大的位移反应可能导致隔震支座失稳或强度破坏,设计时需特别注意。     

餐厨垃圾厌氧消化过酸化系统微生态特征的宏基因组学分析

过酸化失稳是困扰有机废物厌氧消化（AD）过程高效稳定运行的一大难题.为探析不同诱导方式造成过酸化的AD系统微生态特征差异,在餐厨垃圾中温AD反应器中分别引入负荷扰动（R2）、温度及搅拌扰动（R3）以诱发系统过酸化,利用宏基因组学测序技术,对比考察稳定与酸化系统微生物群落结构及主要产甲烷功能路径差异.结果表明,两种方式均成功诱发系统过酸化失稳,过酸化系统中挥发性脂肪酸（VFA）过量富集（R2、R3系统中分别高达（12.53±1.96） g·L^-1和（8.00±0.81） g·L^-1）的同时,丙酸等多碳VFA组分比例大幅升高.R2、R3系统酸化后其产甲烷菌及相关酶受到高浓度VFA的显著抑制,酸积累程度更高的R2受抑制更为明显.且经相关性分析发现,多碳酸尤其是丙酸是抑制产甲烷作用的关键因素.与R2相比,R3具有更高的耗氢能力,耗氢微生物如可耗H₂产酸的Treponema属和氢营养型产甲烷菌Methanoculleus属、Methanospirillum属等相对丰度显著高于R2.酸化系统均以乙酸营养型产甲烷为主要的产甲烷途径,并以Methanosaeta属为主要的乙酸型产甲烷菌.酸化系统中更高含量的乙酸产甲烷途径的AK-PTA酶有利于促进对乙酸的利用,增强厌氧消化微生物菌群对高浓度乙酸的耐受 能力.本研究中的相关结果可为提高有机废物AD微生态抗酸化能力提供理论依据和数据支撑.     

Enrichment and transfer of polycyclic aromatic hydrocarbons (PAHs) through dust aerosol generation from soil to the air

● Compositional patterns of PAHs in dust aerosol vary from soil during dust generation. ● The EF of PAH in dust aerosol is affected by soil texture and soil PAH concentration. ● The sizes of dust aerosol play an important role in the enrichment of HMW-PAHs. Polycyclic aromatic hydrocarbons (PAHs) are major organic pollutants in soil. It is known that they are released to the atmosphere by wind via dust aerosol generation. However, it remains unclear how these pollutants are transferred through the air/soil interface. In this study, dust aerosols were generated in the laboratory using soils (sandy loam and loam) with various physicochemical properties. The PAH concentrations of these soils and their generated dust aerosol were measured, showing that the enrichment factors (EFs) of PAHs were affected by soil texture, PAH contamination level, molecular weight of PAH species and aerosol sizes. The PAHs with higher EFs (6.24–123.35 in dust PM_2.5; 7.02–47.65 in dust PM₁₀) usually had high molecular weights with more than four aromatic rings. In addition, the positive correlation between EFs of PAHs and the total OC_aerosol content of dust aerosol in different particle sizes was also statistically significant (r = 0.440, P < 0.05). This work provides insights into the relationship between atmospheric PAHs and the contaminated soils and the transfer process of PAHs through the soil-air interface.     

A novel speed model for safety evaluation of freeway alignment in Euclidean 3D space

Objective: Operating speed is a critical indicator to evaluate consistency of road alignment and safety. Although extensive studies have been conducted on developing operating speed models, few researchers have considered the interactive influence of horizontal and vertical alignment in 3D space. The purpose of this study is to develop a speed model based on 3D alignment in Euclidean space rather than traditional horizontal and vertical alignment.

Methods: According to the curve theory of differential geometry, a novel method to estimate operating speed is proposed in our study using 3D space curvature instead of traditional horizontal or vertical parameters to describe the spatial geometric properties for a freeway alignment. Speeds of 54 different alignment segments are observed to develop the speed model. Several observing sites of each segment are selected beforehand, and the speeds of more than 300 vehicles in each site are observed. Space curvature is used as an important index to estimate operating speed.

Results: The findings of this study indicated that both horizontal alignment and vertical alignment contribute to space curvature. Space curvature mainly affects direction control operating performance. However, vehicles overcome the effects of gravity along the vertical alignment in the z direction. Results indicate that operating speed exponentially declines with space curvature and that quadratic parabola decline with vertical grade.

Conclusions: It can be concluded that there is a clear correlation between velocity and spatial curvature, which is proved by variance analysis. The estimation results of the speed models are reliable as tested using a real engineering example. The study would provide a scientific basis for safety evaluation of freeway alignment.     

柠檬酸-施氏矿物复合体对Cd和Pb的吸附研究

施氏矿物(Schwertmannite)是酸性矿区废水污染环境中典型的铁硫酸盐次生矿物,由于其较好的吸附能力成为矿区多种重金属的沉积库.环境中同时广泛存在着各种有机质,易与矿物结合形成有机质矿物复合体,从而影响矿物对重金属的吸附行为.目前关于有机质与施氏矿物形成的复合体对重金属的吸附研究相对较少.因此,本研究选取柠檬酸作为天然有机质的代表,研究不同环境条件下柠檬酸施氏矿物复合体对重金属Cd、Pb的吸附.结果表明,复合体保持着施氏矿物基本的矿物学特征,对重金属Cd和Pb的吸附行为表现出不同的趋势:复合体对Cd的吸附量整体上随着Cd浓度和pH值的升高而上升;相反,复合体对Pb的吸附量均比纯施氏矿物要低,并且随着柠檬酸含量的升高吸附量下降越明显;体系中共存的硫酸根离子(SO₄^2-)抑制了复合体对Cd的吸附,而对Pb的吸附则起到促进作用.XRD分析表明柠檬酸抑制了高pH下Pb在矿物表面形成PbSO₄沉淀.FTIR红外谱图进一步证明结合在复合体上的柠檬酸参与了对Cd和Pb的吸附过程.本研究结果有助于更好地预测Cd和Pb在矿区的迁移和归宿.     

报废CRT中废铅回收的环境效益

为研究报废CRT(阴极射线管)中废铅回收的环境效益,基于治理成本法,从实际治理成本与虚拟治理成本两方面,分别对比研究了废铅单向流动模式与循环利用模式的环境影响. 废铅单向流动模式的环境影响被划分为铅矿开采的污染与生态破坏、粗铅冶炼污染、废铅掺混入建材后的污染,该模式中对废铅的实际治理成本与虚拟治理成本分别为329.20与1 322.56元/t,后者是前者的4倍;在废铅循环利用模式的2种典型工艺中,火法回收工艺对废铅的实际治理成本与虚拟治理成本分别为37.80与3.73元/t,湿法回收工艺的实际治理成本与虚拟治理成本分别为135.10与15.06元/t. 与湿法回收工艺对比,火法回收工艺的治理成本更低、环境效益更好,但其需要在粗铅冶炼阶段中将报废CRT锥玻璃与铅精矿按1∶4(质量比)进行搭配回收. 以典型火法回收与湿法回收工艺治理成本的平均值作为循环利用模式的环境治理成本,与单向流动模式相比,其实际治理成本与虚拟治理成本可分别节省242.75与1 313.16元/t,共节省废铅单向流动模式94.2%的环境治理总成本. 铅矿开采固体废物治理成本、铅矿开采生态破坏治理成本与废铅掺混入建材后产生的地下水污染的治理成本位居前三,三者分别占到了废铅单向流动模式环境治理总成本的47%、19%与17%.