环丁砜-哌嗪溶液吸收烟道气中二氧化碳

采用搅拌实验装置,研究环丁砜溶液及不同配比的环丁砜-PZ复合溶液对烟道气中二氧化碳的吸收和解吸性能,揭示了吸收容量与酸碱度、时间之间的内在联系,并对CO2初始逸出温度、试液再生温度、试液再生率、再生pH下降率进行了细致记录分析。实验结果表明,环丁砜-PZ复合溶液配比为0.4∶0.6时:吸收效果最佳,吸收量约为0.126 mol;再生温度最高,为105℃;再生率最高,为90.34%。同时与相同配比的MEA、DEA相比具有较大再生优势。实验结果还表明,环丁砜-PZ复合体系之间存在负交互作用。     

Sorption and Desorption Behavior of Chloroanilines and Chlorophenols on Montmorillonite and Kaolinite

The bioavailability of pollutants, pesticides and/or their degradation products in soil depends on the strength of their sorption by the different soil components, particularly by the clay minerals. This study reports the sorption-desorption behavior of the environmentally hazardous industrial pollutants and certain pesticides degradation products, 3-chloroaniline, 3,4-dichloroaniline, 2,4,6-trichloroaniline, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol on the reference clays kaolinite KGa-1 and Na-montmorillonite SWy-l. In batch studies, 2.0 g of clay were equilibrated with 100.0 mL solutions of each chemical at concentrations ranging from 10.0 to 200.0 mg/L. The uptake of the compounds was deduced from the results of HPLC-UV-Vis analysis. The lipophilic species were best retained by both clay materials. The most lipophilic chemical used in the study, 2,4,6-trichloroaniline, was also the most strongly retained, with sorption of up to 8 mg/g. In desorption experiments, which also relied on HPLC-UV-Vis technique, 2,4,6-trichloroaniline was the least desorbed from montmorillonite. However, on kaolinite all of the compounds under study were irreversibly retained. The experimental data have been modelled according to the Langmuir and Freundlich isotherms. A hypothesis is proposed concerning the sorption mechanism and potential applications of the findings in remediation strategies have been suggested.     

骨炭对水中不同形态Sb吸附和解吸的影响

采用骨炭作为吸附剂，研究其在不同骨炭用量、pH值和温度条件下对水中Sb（Ⅲ）和Sb（Ⅴ）吸附和解吸的影响。结果表明，骨炭对Sb（Ⅲ）的吸附效果远好于Sb（Ⅴ），在0.2~8.0 mmol/L的Sb（Ⅲ）和Sb（Ⅴ）浓度下，骨炭对这2种形态Sb的去除率分别为46.1%~78.6%和9.6%~31.7%。采用Langmuir方程和Freundlich方程均可以很好地拟合骨炭对Sb（Ⅲ）和Sb（Ⅴ）的吸附，Sb（Ⅲ）和Sb（Ⅴ）的最大吸附容量分别为110.1034 mg/g和17.4167 mg/g。骨炭对Sb（Ⅲ）的解吸也大于对Sb（Ⅴ）的解吸。骨炭对Sb（Ⅲ）和Sb（Ⅴ）的吸附受不同骨炭用量、pH值和温度影响。     

钠基蒙脱土对亚甲基蓝的吸附和解吸研究

采用正交实验方法,确定了钠基蒙脱土吸附亚甲基蓝染料的最佳吸附条件.采用试剂再生法、超声波法、高温焙烧法、氢氧化钠—高温焙烧结合法对钠基蒙脱土吸附亚甲基蓝进行解吸.用扫描电子显微镜照片和红外光谱对吸附前后的钠基蒙脱土的结构进行表征.实验结果表明:在亚甲基蓝溶液pH为10、吸附温度为60℃、亚甲基蓝质量浓度为1 300 m...     

改性多壁碳纳米管对水中Cd~（2＋）的去除

为了增加多壁碳纳米管（multiwall carbon nanotubers,MWNTs）对水中Cd2＋的吸附量,使用混酸对多壁碳纳米管进行氧化处理,采用红外光谱进行结果表征,并探讨了吸附时间、pH值和MWNTs的使用量、Cd2＋的浓度及干扰离子对镉离子吸附的影响。结果表明,吸附时间为1.5 h、pH为5.3、吸附效果最佳,随MWNTs量的增加Cd2＋去除量增加,共存的阳离子会降低对Cd2＋的吸附效果,对Cd2＋的吸附符合Longmuir吸附定律。研究同时表明,pH小于2时Cd2＋能容易从碳纳米管上解吸。初步探讨了Cd2＋吸附机制。     

Sorption and desorption kinetics of diuron,fluometuron, prometryn and pyrithiobac sodium in soils

Abstract

The sorption and desorption characteristics of four herbicides (diuron, fluometuron, prometryn and pyrithiobac‐sodium) in three different cotton growing soils of Australia was investigated. Kinetics and equilibrium sorption and desorption isotherms were determined using the batch equilibrium technique. Sorption was rapid (> 80% in 2 h) and sorption equilibrium was achieved within a short period of time (ca 4 h) for all herbicides. Sorption isotherms of the four herbicides were described by Freundlich equation with an r² value > 0.98. The herbicide sorption as measured by the distribution coefficient (K_d) values ranged from 3.24 to 5.71 L/kg for diuron, 0.44 to 1.13 L/kg for fluometuron, 1.78 to 6.04 L/kg for prometryn and 0.22 to 0.59 L/kg for pyrithiobac‐sodium. Sorption of herbicides was higher in the Moree soil than in Narrabri and Wee Waa soils. When the K_d values were normalised to organic carbon content of the soils (K_oC), it suggested that the affinity of the herbicides to the organic carbon increased in the order: pyrithiobac‐sodium < fluometuron < prometryn < diuron. The desorption isotherms were also adequately described by the Freundlich equation. For desorption, all herbicides exhibited hysteresis and the hysteresis was stronger for highly sorbed herbicides (diuron and prometryn) than the weakly sorbed herbicides (fluometuron and pyrithiobac‐sodium). Hysteresis was also quantified as the percentage of sorbed herbicides which is not released during the desorption step ω = [n_ad / n_de ‐1] x 100). Soil type and initial concentration had significant effect on ω. The effect of sorption and desorption properties of these four herbicides on the off‐site transport to contaminate surface and groundwater are also discussed in this paper.     

A new direct thermal desorption-GC/MS method: Organic speciation of ambient particulate matter collected in Golden, BC

Particulate matter having an aerodynamic diameter less than 2.5 μm (PM2.5) is thought to be implicated in a number of medical conditions, including cancer, rheumatoid arthritis, heart attack, and aging. However, very little chemical speciation data is available for the organic fraction of ambient aerosols. A new direct thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) method was developed for the analysis of the organic fraction of PM2.5. Samples were collected in Golden, British Columbia, over a 15-month period. n-Alkanes constituted 33–98% by mass of the organic compounds identified. PAHs accounted for 1–65% and biomarkers (hopanes and steranes) 1–8% of the organic mass. Annual mean concentrations were: n-alkanes (0.07–1.55 ng m⁻³), 16 PAHs (0.02–1.83 ng m⁻³), and biomarkers (0.02–0.18 ng m⁻³). Daily levels of these organics were 4.89–74.38 ng m⁻³, 0.27–100.24 ng m⁻³, 0.14–4.39 ng m⁻³, respectively. Ratios of organic carbon to elemental carbon (OC/EC) and trends over time were similar to those observed for PM2.5. There was no clear seasonal variation in the distribution of petroleum biomarkers, but elevated levels of other organic species were observed during the winter. Strong correlations between PAHs and EC, and between petroleum biomarkers and EC, suggest a common emission source – most likely motor vehicles and space heating.     

Effects of thermal desorption on the composition of two coking plant soils: impact on solvent extractable organic compounds and metal bioavailability

To evaluate the efficiency and the influence of thermal desorption on the soil organic compartment, contaminated soils from coking plant sites (NM and H) were compared to their counterparts treated with thermodesorption. The extractable organic matter, and the metal content and distribution with soil compartments were studied.In both thermodesorbed soils, PAH (polycyclic aromatic hydrocarbon) degradation exceeded 90%. However, the thermal desorption led not only to a volatilization of the organic compounds but also to the condensation of extractable organic matter.The treatments only affected the Fe and Zn distribution within the more stable fractions, whereas the organic compound degradation did not affect their mobility and availability.     

构造煤孔隙结构与瓦斯耦合特性研究

利用压汞法、低温氮吸附法、瓦斯等温吸附和解吸试验对平煤八矿构造煤和共生原生结构煤进行综合分析,探讨了构造煤孔隙结构与瓦斯耦合特性.结果表明,构造煤以微孔为主,中孔和大孔相对发育且含较多细颈瓶孔,孔隙连通性差.与共生原生结构煤相比,构造煤各孔径阶段的孔容和孔比表面积都有所增加.构造煤比表面积的增加具有阶段性,即孔径＜ 1.2 nm时为慢增加阶段,孔径=1.2 ～ 4.9nm时为快增加阶段,孔径＞4.9 nm时为稳定阶段.构造煤极限瓦斯吸附量a的增大与比表面积快增加阶段关系密切,但小于其BET比表面积的增幅.瓦斯解吸初期0～2 min内构造煤瓦斯解吸速度和解吸量明显大于共生原生结构煤,与中孔和大孔的变化一致,2 min以后瓦斯解吸迅速衰减.低煤体强度、高瓦斯含量的构造煤以气-煤共溶体形式储集更多弹性潜能,突然卸压时瓦斯膨胀能迅速释放,煤层中发育的构造煤增加了煤与瓦斯突出的危险性.     

空气氧化解吸NO络合吸收产物试验研究

Fe(Ⅱ) EDTA易被氧化为对NO无吸收能力的Fe(Ⅲ)EDTA,为实现Fe(Ⅱ)EDTA的循环使用,提出了Fe(Ⅱ)EDTA络合吸收-空气氧化解吸-铁屑还原再生组合脱除NO新工艺.采用空气氧化解吸络合吸收产物Fe(Ⅱ) EDTA (NO)中NO的方法,研究了温度及压力对Fe(Ⅱ)EDTA(NO)空气氧化解吸过程的影响.结果表明,0.4 MPa、333K为较优的解吸条件.该工艺可循环脱除NO,成本低、效率高,能有效回收NO2资源.