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1.
活性炭纤维(ACF)是一种新型功能性炭材料.应用粘胶基活性炭纤维(cellulose-ACF)对低浓度SO2(571mg/m3)进行吸附氧化实验,通过改变活性炭纤维量、SO2浓度、氧浓度,观察cellulose-ACF脱除低浓度SO2能力的变化规律.实验结果表明,随着活性炭纤维量、氧浓度的增加,cellulose-ACF对低浓度SO2的脱除能力增强.在此基础上展望活性炭纤维在大气环保领域的应用前景. 相似文献
2.
通过固定床实验系统研究烟气脱除零价汞的实验,首先研究了滤袋常用的聚苯硫醚(polyphenylene sulfide,PPS)以及活性炭纤维(activated carbon fiber,ACF)在不同温度、不同气体组分下负载V 2O 5-WO 3/TiO 2催化剂,对模拟燃煤烟气中零价汞(Hg 0)的脱除效果。然后对比研究了活性炭纤维协同滤袋常用纤维负载催化剂后,对模拟燃煤烟气中Hg 0的脱除性能。结果表明,在汞蒸气入口浓度为50 μg/m 3,纯N 2气氛下,当温度为25℃时,两者脱除率均能达到99%,当温度为200℃,负载催化剂的活性炭纤维脱除率在30%左右,PPS纤维仅为10%左右。在200℃情况下,模拟烟气的组分为N 2+O 2时,2种纤维的Hg 0脱除率提高了10%~20%,当在混合气体中添加0.01‰后,负载催化剂的PPS纤维Hg 0脱除率能达到80%,活性炭纤维Hg 0脱除率能达到98%。当温度为200℃,模拟烟气的组分为N 2+O 2+HCl时,不同性能掺炭纤维负载催化剂后Hg 0脱除率在69%~95%范围之间变化,其中PPS掺炭纤维对Hg 0脱除效率最高达到95%,因此,负载V 2O 5-WO 3/TiO 2催化剂的PPS掺炭纤维能在高温烟气中保持较高的Hg 0脱除率。 相似文献
3.
近年来,低温等离子体技术以及纳米TiO 2光催化技术在烟气脱硫中的应用越来越引起人们的关注。利用填充床反应器将这2种技术有机地结合起来,进行了大量脱硫实验研究。研究结果表明,等离子体协同光催化去除烟气中的SO 2与单独采用等离子体技术相比,其SO 2的去除率可提高5%~20%。同时,探讨了等离子体协同TiO 2光催化剂的脱硫机理,分别研究了外加电压、气体流量和SO 2初始浓度等因素对脱硫效率的影响。实验结果表明,当SO 2初始浓度为800 mg/m 3,输入电压为17.5 kV,气体流量为0.2 m 3/h时,SO 2脱除率可以达到77.6%。 相似文献
4.
利用浸渍法将纳米TiO 2-Ag负载于粘胶基活性炭纤维上进行改性来处理低浓度氨气,扫描电镜观测和能量色散谱分析表明纳米TiO 2和Ag均较成功地负载于VACF表面上,改性VACF对氨气脱除性能良好,最大脱除率为93.3%;当Ag +掺杂量为TiO 2含量的0.5wt%时氨气脱除率达到最大值;存在最佳相对湿度为55%;在氨气浓度为13~65 mg/m3范围内,浓度越低,脱除效果越好;处理较高浓度氨气可通过增加改性VACF用量;随着反应连续进行,改性VACF稳定性受到影响,但仍具有脱除氨气能力。 相似文献
5.
通过系列杯罐试验混凝处理合流污水,采用硫酸铝(Al 2(SO 4) 3)、硫酸铁(Fe 2(SO 4) 3)、聚合氯化铝(PAC)和聚合氯化铝铁(PAFC)4种混凝剂均能有效去除污水中的 TP、PO 3-4-P、SS和COD。聚合金属盐(PAC和PAFC)混凝处理效果优于金属盐(Al 2(SO 4) 3和Fe 2(SO 4) 3),达到相同的处理效果的投加量明显低于后者。助凝剂采用聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、自制的高分子聚合物(AN)和活化硅酸(AS),在保持较低混凝剂投加量的条件下可明显提高污水处理效果;添加助凝剂对强化PO 3-4-P的去除作用不明显,PO 3-4-P的去除仅与混凝剂的投加量相关。混凝剂和助凝剂对污水中NH 3-N的去除作用相对不显著。SS去除率随混凝剂投加量的变化趋势说明混凝的机理较为复杂,可能存在多种混凝机理共同作用。 相似文献
6.
为了有效地控制铅污染,利用序批式反应器(sequencing batch reactor,SBR)培养的以醋酸钠为碳源的好氧颗粒污泥作为吸附剂,进行生物吸附含铅废水的效能和机理的研究。通过考察酸度、接触时间和Pb 2+初始浓度等因素的影响,验证好氧颗粒污泥吸附模型,并利用不同的脱附剂,进一步解析其生物吸附的Pb 2+。实验结果表明, 酸度是影响好氧颗粒污泥生物吸附Pb 2+的关键因素,当初始pH为5时,好氧颗粒污泥对含铅废水生物吸附效果最好。对低浓度(0~20 mg/L)含铅废水, 10 min后可快速达到吸附平衡。好氧颗粒污泥对Pb 2+的实测饱和吸附量为101.97±9.00 mg/g,符合朗缪尔(Langmuir)模型。好氧颗粒污泥生物吸附Pb 2+的过程,伴随着pH值的升高和K +、 Ca 2+、 Mg 2+的释放,此现象揭示离子交换作用是好氧颗粒污泥生物吸附Pb 2+的机理之一。此外,脱附剂HNO 3、EDTA和CaCl 2能实现Pb 2+的回收和好氧颗粒污泥的重复利用。 相似文献
7.
以城市污水处理厂剩余污泥为原料,以ZnCl 2为活化剂制取污泥基活性炭。以此污泥基活性炭为吸附剂,对含Cu 2+的废水进行了吸附实验研究。考察了溶液pH值、Cu 2+的起始浓度对Cu 2+离子吸附量的影响;利用等温吸附实验作出吸附等温线,并考察了污泥基活性炭吸附剂吸附Cu 2+的动力学方程。实验结果表明,污泥基活性炭对Cu 2+具有良好的吸附性能。吸附的最佳pH值为5;吸附符合Langmuir和Freundlich吸附等温方程,吸附为优惠吸附,吸附量随着吸附质溶液浓度的增加而增大;吸附平衡时间为4 h,吸附动力学符合二级动力学方程。 相似文献
8.
为了降低工业废气中的硫化氢去除工艺成本和运行费用,对三价铁盐吸收与氧化亚铁硫杆菌对Fe 2+的生物氧化联合作用脱除H 2S进行了研究。通过生物氧化塔中的固定化氧化亚铁硫杆菌细胞再生的Fe 3+溶液,在H 2S还原吸收塔中脱除H 2S。通过单因素实验分别优化了生物氧化塔和H 2S吸收塔的运行参数,在生物氧化塔曝气量为150 L/h,停留时间为11 h,吸收液中Fe 3+浓度为0.121~0.143 mol/L,吸收液流量为0.3 L/h,进气量为100 L/h条件下,进气中H 2S浓度分别为2.28和9.11 mg/L,系统连续运行至200 min时趋于相对稳定,当系统连续运行稳定时,H 2S的脱除率可分别达到95%和91%,脱除效果显著。 相似文献
9.
为进一步拓展天然高分子絮凝剂壳聚糖的应用范围,以壳聚糖、L-半胱氨酸为原料,通过酰胺化反应制备一种具有重金属捕集功能的高分子重金属絮凝剂-2-氨基-3-巯基丙酰壳聚糖(MCC),研究了水体中常见的阴阳离子、有机配位剂及浊度对MCC除镉性能的影响,探讨了絮体形貌与絮体分形维数及絮凝除镉效果间的关系。结果表明,Na +、Cl -、NO 3-、F -、SO 42-的存在对MCC除Cd 2+均有促进作用,Ca 2+表现为明显的抑制作用;低浓度的EDTA对除镉有促进作用,随着EDTA浓度的增大,逐渐转为抑制作用;低浓度的腐殖酸对MCC去除Cd 2+有显著的促进作用;在一定范围内,浊度可促进 MCC对Cd 2+的去除;絮体间空隙越多,絮体分形维数越小,除镉效果越好。 相似文献
10.
以NO -3为光催化剂,在紫外灯照射下,对甲基橙溶液进行光催化脱色。结果表明,叔丁醇、甲醇和乙醇对催化脱色反应有抑制作用; KBr和Na 2SO 4对脱色反应均有促进作用;而且KBr的加入量存在最佳值; Na 2SO 4的促进作用随Na 2SO 4的量的增加逐渐增强。Na 2CO 3的存在对甲基橙的脱色反应没有影响。K 2S 3O 8和NO -3之间存在较强的协同作用;KIO 3和NO -3之间存在相加作用;KBrO 3和NO -3之间存在拮抗作用。 相似文献
11.
Aircraft measurements of air pollutants were made to investigate the characteristic features of long-range transport of sulfur compounds over the Yellow Sea for the periods of 26–27 April and 7–10 November in 1998, and 9–11 April and 19 June in 1999, together with aerosol measurements at the Taean background station in Korea. The overall mean concentrations of SO 2, O 3 and aerosol number in the boundary layer for the observation period ranged 0.1–7.4 ppb 32.1–64.1 ppb and 1.0–143.6 cm −3, respectively. It was found that the air mass over the Yellow Sea had a character of both the polluted continental air and clean background air, and the sulfur transport was mainly confined in the atmospheric boundary layer. The median of SO 2 concentration within the boundary layer was about 0.1–2.2 ppb. However, on 8 November, 1998, the mean concentrations of SO 2 and aerosol number increased up to 7.4 ppb and 109.5 cm −3, respectively, in the boundary layer, whereas O 3 concentration decreased remarkably. This enhanced SO 2 concentration occurred in low level westerly air stream from China to Korea. Aerosol analyses at the downstream site of Taean in Korea showed 2–3 times higher sulfate concentration than that of other sampling days, indicating a significant amount of SO 2 conversion to non sea-salt sulfate during the long-range transport. 相似文献
12.
Previous studies demonstrated that short-term exposure to gaseous pollutants (nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O3)) had a greater adverse effect on cardiovascular disease. However, little evidence exists regarding the synergy between gaseous pollutants and cardiovascular disease (CVD). Therefore, we aimed to estimate the effect of individual gaseous pollutants on hospital admissions for CVD and to explore the possible synergistic effects between gaseous pollutants. Daily hospitalization counts for CVD were collected from January 1, 2014, to December 31, 2015. We also collected daily time series on gaseous pollutants from the Environment of the People’s Republic of China, including NO2, SO2, and O3. We used distributed lag nonlinear models (DLNMs) to assess the association of individual gaseous pollutants on CVD hospitalization, after controlling for seasonality, day of the week, public holidays, and weather variables. Then, we explored the variability across age and sex groups. In addition, we analyzed the synergistic effects between gaseous pollutants on CVD. Extremely low NO2 and SO2 increase the risk of CVD in all subgroup at lag 7 days. The greatest effect of high concentration of SO2 was observed in male and the elderly (≥ 65 years) at lag 3 days. Greater effects of high concentration of O3 were more pronounced in the young (< 65 years) and female at lag 3 days, while the effect of low concentration of O3 was greater in male and the young (< 65 years) at lag 0 day. We found a synergistic effect between NO2 and SO2 for CVD, as well as between SO2 and O3. The synergistic effects of NO2 and SO2 on CVD were stronger in the elderly (≥ 65) and female. The female was sensitive to synergistic effects of SO2-O3 and NO2-O3. Interestingly, we found that there was a risk of CVD in the susceptible population even for gaseous pollutant concentrations below the National Environmental Quality Standard. The synergy between NO2 and SO2 was significantly associated with cardiovascular disease hospitalization in the elderly (≥ 65). This study provides evidence for the synergistic effect of gaseous pollutants on hospital admissions for cardiovascular disease. 相似文献
13.
Numerical precipitation scavenging models are used to investigate the relationship between the inflow concentrations of sulfur species to precipitation systems and the resulting sulfur wet deposition. Simulations have been made for summer and winter seasons using concentration ranges of SO 2, aerosol SO 42−, H 2O 2 and O 3 appropriate for the eastern U.S. summer simulations use one-dimensional timedependent convective cloud and scavenging models; winter simulations use two-dimensional steady-state warm-frontal models. Sulfur scavenging mechanisms include nucleation scavenging of aerosol, aqueous reactions of H 2O 2, O 3 and HCHO with S(IV), and nonreactive S(IV) scavenging. Over the wide range of conditions that have been examined, the relation between sulfur inflow and sulfur wet deposition varies from nearly linear to strongly nonlinear. The degree of nonlinearity is most affected by aerosol SO 42− levels and relative levels of SO 2 vs H 2O 2. Higher aerosol SO 42− levels (as found in summer) produce a more linear relation. The greatest nonlinearity occurs when SO 2 exceeds H 2O 2. Winter simulations show more nonlinearity than summer simulations. 相似文献
14.
A technique has been employed by which transboundary mass fluxes of SO 2, SO 42−, NOx, NO 3−, and O 3 are assessed. As an example the results of one measuring flight are presented. This flight was carried out along the eastern and western border of the Netherlands. An uncertainty analysis yields that the accuracy of calculated transboundary mass fluxes is most dependent on the accuracy of the values for the depth of the mixing layer and the wind velocity. Mass fluxes calculated in this case study appear to be accurate within ± 55 %, apart from inaccuracies due to non-representativity of concentration and wind data with respect to the mixing layer. On the basis of the uncertainty analysis, recommendations for further improvement of the method are made so that a reduction of this ± 55 % to ± 20 % can be achieved. Finally, conclusions about the origin of the observed pollution are drawn. 相似文献
15.
Total suspended particulate (TSP) samples were collected during dust, haze, and two festival events (Holi and Diwali) from February 2009 to June 2010. Pollutant gases (NO 2, SO 2, and O 3) along with the meteorological parameters were also measured during the four pollution events at Agra. The concentration of pollutant gases decreases during dust events (DEs), but the levels of the gases increase during other pollution events indicating the impact of anthropogenic emissions. The mass concentrations were about two times higher during pollution events than normal days (NDs). High TSP concentrations during Holi and Diwali events may be attributed to anthropogenic activities while increased combustion sources in addition to stagnant meteorological conditions contributed to high TSP mass during haze events. On the other hand, long-range transport of atmospheric particles plays a major role during DEs. In the dust samples, Ca 2+, Cl ?, NO 3 ?, and SO 4 2? were the most abundant ions and Ca 2+ alone accounted for 22 % of the total ionic mass, while during haze event, the concentrations of secondary aerosols species, viz., NO 3 ?, SO 4 2?, and NH 4 +, were 3.6, 3.3, and 5.1 times higher than the normal days. During Diwali, SO 4 2? concentration (17.8 μg?m ?3) was highest followed by NO 3 ?, K +, and Cl ? while the Holi samples were strongly enriched with Cl ? and K + which together made up 32.7 % of the total water-soluble ions. The ion balances indicate that the haze samples were acidic. On the other hand, Holi, Diwali, and DE samples were enriched with cations. The carbonaceous aerosol shows strong variation with the highest concentration during Holi followed by haze, Diwali, DEs, and NDs. However, the secondary organic carbon concentration follows the order haze > DEs > Diwali > Holi > NDs. The scanning electron microscope/EDX results indicate that KCl and carbon-rich particles were more dominant during Holi and haze events while DE samples were enriched with particles of crustal origin. 相似文献
16.
There is an appreciable chemical interaction between SO 2 and photochemical smog which depends on the concentration of SO 2 and water vapor. The rate of decay of SO 2 concentration is greatly increased in the presence of photochemical smog. With 0.75 ppm SO 2, a light-scattering aerosol is produced in dry systems and systems at 22 and 55% relative humidity (RH). Aerosol is not observed until after the NO 2 peak has been reached and the NO concentration has fallen to a very low value. The formation of aerosol corresponds in time to the region of most rapid decrease in the SO 2 profile. In systems at 65% RH or with smaller amounts of SO 2, no light scattering is observed, but the percentage of SO 2 disappearing is greater. In relatively dry systems the presence of SO 2 results in a general slowing down of the photochemical smog reactions. In systems containing water vapor concentrations comparable to those found in the atmosphere, the inhibiting influence of SO 2 on the smog reaction is less pronounced. However, the maximum concentration of oxidant produced by the photochemical smog reactions is significantly lower when SO 2 is present. 相似文献
17.
Activated carbon fiber (ACF) has become an emerging activator for peroxydisulfate (PDS) to generate sulfate radical (SO 4??). However, the relative low activation efficiency and poor contaminant mineralization limited its widespread application. Herein, ultrasound (US) was introduced to the ACF activated PDS system, and the synergistic effect of US and ACF in PDS activation and the enhancement of contaminant mineralization were investigated. The synergistic effect of US and ACF was observed in the PDS activation to decolorize orange G (OG). The decolorization efficiency increased with increasing ACF loading and US power, and PDS/OG ratio from 1 to 40. The activation energy was determined to be 24.065 kJ/mol. The radical-induced decolorization of OG took place on the surface of ACF, and both SO 4?? and hydroxyl radical ( ?OH) contributed to OG decolorization. The azo bond and naphthalene ring on OG were destructed to other aromatic intermediates and finally mineralized to CO 2 and H 2O. The introduction of US in the ACF/PDS system significantly enhanced the mineralization of OG. The combination of US and PDS was highly efficient to activate PDS to decolorize azo dyes. Moreover, the introduction of US remarkably improved the contaminant mineralization. 相似文献
18.
Fe 2O 3 and CeO 2 modified activated coke (AC) synthesized by the equivalent-volume impregnation were employed to remove elemental mercury (Hg 0) from simulated flue gas at a low temperature. Effects of the mass ratio of Fe 2O 3 and CeO 2, reaction temperature, and individual flue gas components including O 2, NO, SO 2, and H 2O (g) on Hg 0 removal efficiency of impregnated AC were investigated. The samples were characterized by Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Results showed that with optimal mass percentage of 3 % Fe 2O 3 and 3 % CeO 2 on Fe3Ce3/AC, the Hg 0 removal efficiency could reach an average of 88.29 % at 110 °C. Besides, it was observed that O 2 and NO exhibited a promotional effect on Hg 0 removal, H 2O (g) exerted a suppressive effect, and SO 2 showed an insignificant inhibition without O 2 to some extent. The analysis of XPS indicated that the main species of mercury on used Fe3Ce3/AC was HgO, which implied that adsorption and catalytic oxidation were both included in Hg 0 removal. Furthermore, the lattice oxygen, chemisorbed oxygen, and/or weakly bonded oxygen species made a contribution to Hg 0 oxidation. 相似文献
19.
Surface fluxes of O 3, CO 2 and SO 2 were estimated from a variational method by using measured concentrations and variances of these trace gases. The measurements were taken over a deciduous forest when it was fully leafed during the summer of 1988 and when it was leafless during the winter of 1990. A flux–variance relation and a flux–gradient relation were employed as constraints in a cost function which is minimized to find the optimal estimate of concentration fluxes of the gases under study. Fluxes of O 3, CO 2 and SO 2 from the variational method were compared with fluxes estimated by the flux–variance relation and measured using an eddy correlation technique. Results show that the variational method improves the estimates of fluxes. 相似文献
20.
A laboratory study was conducted of the heterogeneous catalysis of sulfur dioxide at ppm concentrations in air by insoluble particles of CaCO 2, V 2O 5, Fe 20 3, flyash from a coal-burning power plant, MnCO 2, activated carbon, and suspended particulate matter from urban air. The investigalion was performed by utilizing a new technique for aerosol stabilization which consists of depositing the aerosol on Teflon beads in a fluidized bed. The Teflon beads with deposited aerosol particles were then packed into a flow reactor. Progress of the chemical reaction of SO 2 with deposited particles was continuously monitored by determining the SO 2 concentrations in the reactor effluent with a microcoulometer. In this investigation, CaCOg, V 2O 5, and flyash were essentially inert to SO 2 at room temperature. Fe 2O 3, activated carbon, MnO 2, and suspended particulate matter from urban air sorbed SO 2 from air streams with up to 14.4 ppm SO 2 in air. Evidence is presented which suggests that a substantial part of the sorbed SO 2 was physically adsorbed. Bioassay procedures which utilize pulmonary flow resistance changes in guinea pigs to monitor response to inhaled SO 2-aerosol mixtures in air have indicated the weak or non-potentiating capacity of insoluble aerosols as contrasted to soluble aerosols. Potentiating response of an aerosol appears to be strongly associated with reaction of SO 2 in a water droplet containing aerosol ions and not with physically adsorbed SO 2 on an insoluble aerosol. 相似文献
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