活性炭孔结构对卷烟烟气过滤效率的影响

综述了活性炭孔径分布和比表面积对卷烟烟气过滤效率的影响,介绍了利用气体吸附法表征活性炭孔径分布的方法,并对活性炭滤嘴在低焦油卷烟设计中的应用进行了展望。     

烟用丙纤滤棒胶粘剂的研究

本文论述了烟用丙纤滤棒的性能及应用，考察了胶粘剂对滤棒的性能的影响。结果表明，胶粘剂的使用能够提高ＰＰ滤棒的各项性能指标，并可节省用丝量。     

Sorption of Acetaldehyde and Hexanal in Trace Concentrations on Carbon‐Based Adsorbents

Adsorption processes are frequently applied to separate traces of hazardous and toxic substances from gas streams. Hence, knowledge of sorption characteristics of these substances on standard adsorbents is essential. Sorption of hexanal and acetaldehyde from a nitrogen gas stream in trace concentrations on activated carbon and ordered mesoporous carbon‐based adsorbents (CMK) is studied. A magnetic suspension balance and an attached gaschromatograph‐mass spectrometer were used to analyze the sorption process both gravimetrically and spectrometrically. Both types of adsorbents show a higher capacity for hexanal than acetaldehyde. The activated carbon exhibits considerable differences in regard to desorption of hexanal compared to the mesoporous CMK.     

活性碳纤维素在烟滤嘴中的应用

本文采用活性碳纤维素与醋酸纤维配合使用,制成一种新型的复合滤嘴材料,有效地除去了尼古丁和焦油。     

Desorption‐ and Decomposition‐Based Techniques for the Regeneration of Activated Carbon

Activated carbon (AC) is an adsorbent used in most adsorption processes related to micro removal of pollutants from the water phase, but the application is limited due to high costs and environmental issues related to the disposal after saturation. Different regeneration techniques, reducing costs and minimizing environmental impact, are reported for the reuse of saturated AC. These techniques can be performed via two separate strands: regeneration based only on desorption of adsorbed compounds in AC, or based on the decomposition of pollutants adsorbed on AC. Literature on the regeneration of saturated ACs is reviewed and promising techniques are highlighted. One of the most challenging bottlenecks preventing the commercial application of regeneration technologies is the difficulty of scaling‐up.     

An adsorption equilibrium model for Type 5 isotherms

Vapor adsorption on porous materials for non-wetting adsorbent–adsorbate pairs, characterized by a Type 5 isotherm, results in low loading at low relative pressure and increased loading due to capillary condensation behavior at higher relative pressure. The relationship between capillary condensation and the Kelvin equation suggests that a simple expression can be developed in which the adsorption equilibrium is obtained from an integrated pore size distribution function. This new expression is shown to describe the Type 5 isotherms of water adsorption on activated carbon. In addition, this expression has useful properties including: (1) finite saturation limit, (2) readily calculated Henry’s constant, and (3) readily calculated heat of adsorption, (4) can be written explicitly in terms of partial pressure or adsorbed phase loading and (5) parameter values attributable to the distribution function.     

均粒石英砂滤料快滤池的生产性试验与应用

介绍均粒石英砂滤料快滤池的生产性试验与应用 ,在不改变滤池结构、反冲洗方法和操作习惯的条件下 ,仅将快滤池的传统滤层改为均粒石英砂滤层 ,产水量提高 15 % ,而滤层的费用仅增加7%。     

Effects of high relative humidity on the dynamic adsorption of dimethyl methylphosphonate (DMMP) on activated carbon

The effects of high relative humidity (RH) on the breakthrough of the nerve agent simulant dimethyl methylphosphonate (DMMP) vapor in beds of ASC-impregnated, activated carbon were investigated. Maximum concentrations of DMMP at room temperature and RH > 60% were found to be lower by more than an order of magnitude than in dry air. The breakthrough time (t_B) of 1.2 × 10⁻⁴ g l⁻¹ DMMP in pre-humidified beds and humid air of RH = 90% was shortened by a factor of 1.6 relative to adsorption in dry beds and dry air. Analysis of the breakthrough curves according to the Wheeler–Jonas model indicated that the high RH lowered the dynamic adsorption capacity (W_E) but had nearly no effect on the critical bed weight (W_C). The reduction of W_E by humidity correlates with the observed displacement of adsorbed water by DMMP. The use of DMMP for testing filter performance is limited to low and intermediate relative humidities. On the other hand, DMMP in dry air can be used to advantage for testing the capacity of new or used respirator filters and for the detection of filter channeling.     

PEEK: An excellent precursor for activated carbon production for high temperature application

A series of activated carbons (AC) with high apparent surface area and very high micropore volumes were prepared from granulated PEEK (poly[oxy-1,4-phenylene-oxy-1,4-phenylene-carbonyl-1,4-phenylene]) by physical activation with CO₂ at different temperatures and different activation times. The carbonisation yields at 873, 1073 and 1173 K were 57, 52 and 51%. As the activation temperature increased, between 873 and 1173 K, the burn-off, the micropore volume and mean pore size increased too. Those prepared at 1173 K, with 74% burn-off, present an extremely high apparent surface area (2874 m² g^− 1) and a very high micropore volume (1.27 cm³ g^− 1). The presence of pyrone groups, identified by FTIR, on the AC surface corroborates the prevalence of a basic point of zero charge, always higher than 9.2. The thermal stability was checked by thermogravimetric analysis and as the carbonisation temperature increased the thermal stability of the char increased too. All AC obtained from PEEK by physical activation at 1173 K are thermally resistant, as at 1073 K the loss of the initial mass was less than 15%. The collective results confirm that PEEK is an excellent precursor for preparing AC with a high carbonisation yield, a high micropore volume and apparent surface area and a very high resistance at elevated temperature.     

An accurate volumetric differential pressure method for the determination of hydrogen storage capacity at high pressures in carbon materials

Widely different hydrogen adsorption capacities have been reported for a variety of carbon materials which have attracted attention for hydrogen storage. This has led to doubts as to the validity of some of the claims and it has been suggested that one possible reason for the disparate hydrogen sorption capacities may lie in the inaccurate measurement of the hydrogen adsorbed. The aim of the work described in this paper was to make a contribution to this debate by developing a means and method of producing repeatable, accurate measurements of hydrogen sorption capacity in carbon materials. The apparatus developed is a volumetric differential pressure set-up operating at up to 10 MPa and the method has a conservative limit of detection of 0.1 wt% and an accuracy of ±0.05 wt%, using 1.0-2.5 g samples of the carbon materials studied. These included a carbon nanofiber sample and a series of activated carbons, the latter displaying a direct correlation between the BET effective surface area and the hydrogen sorption capacity of the materials. The amount of hydrogen adsorbed was less than 1 wt% for all the carbons examined.     

Adsorption of SO2 on Activated Carbon for Low Gas Concentrations

Adsorption experiments of SO₂ on activated carbon has been carried out for low concentrations (about 100 ppm) at room temperature (15 to 33 °C) with varying humidity in the air. The breakthrough curves show that at high relative humidity or relative higher SO₂ concentration, the load capacity increases with respect to temperature. The humidity of the air is also of benefit to the load capacity of SO₂. When an adsorption process is interrupted and the activated carbon is kept closed for a while, the SO₂ concentration at the exit of a fixed‐bed adsorber is similar to that of the fresh activated carbon and begins at a very low value. It appears that the sorption potential has been refreshed after the storage period. Analysis of desorption experiments by simultaneous thermal analysis combined with mass spectrometry (MS) after loading, shows that the physisorbed SO₂ and H₂O are desorbed at low temperatures. At higher temperatures, the MS peak of SO₂ and H₂O occur at the same time. Compared with desorption immediately after loading, after one day, the desorption peak due to the physisorbed SO₂ disappears. From this, it can be concluded that the refreshment of the loading capacity of the activated carbon after storage is mainly due to a change in the nature of the SO₂ from a physisorbed state to a chemisorbed form. The same mechanism leads to a continuous refreshment of the sorption potential by means of a chemical reaction during the adsorption process.     

Filter Cake Washing of Mesoporous Particles

Particle synthesis in liquid phase usually requires a subsequent washing step in order to remove undesirable impurities such as unreacted educts, byproducts, solvents and salts. In particular, the washing of mesoporous particles is a challenging task due to large specific surface areas and void volumes. The filter cake washing of mesoporous SiO₂ particles contaminated either with an adsorbing fluorescent dye or sodium sulfate is presented. The effects of wash liquid mass flow rate, mean particle size, and mean pore size on the wash efficiency were investigated. Especially the interaction between impurities and the solid surface, and thereby the initial impurity distribution within the filter cake, led to distinctive washing behaviors.     

Effect of adsorbent composition on H2S removal on sewage sludge-based materials enriched with carbonaceous phase

In order to improve the carbonaceous phase content in sewage sludge derived adsorbents, dewatered sludge was physically mixed with polystyrene sulfonic acid-co maleic acid sodium salt with the following ratios of polymer to sludge: 10:90, 30:70, 50:50 and 70:30. The samples, along with the pure precursors, were carbonized at 950 °C and then washed in water to remove the excess of sodium salt/hydroxide. The performance of materials as H₂S adsorbents was tested using a home-developed dynamic breakthrough test. The samples, before and after adsorption process, were characterized by adsorption of nitrogen, potentiometric titration, thermal analysis and SEM. Differences in the performance were linked to the surface properties. It was found that mixing polymer with sludge increases the amount of H₂S adsorbed/oxidized in comparison with the adsorbents obtained from pure precursors (sludge or polymer). Sewage sludge provides the catalytic centers for hydrogen sulfide oxidation whereas a carbonaceous phase contributes to an increase in the dispersion of catalytic centers and provides more “storage space” in its micropores. There is an optimal ratio in the composition of the precursors for which the best performance is achieved. When the content of the polymer is too high, the “buffering capacity” of the sludge-derived phase is not enough to neutralize the suppressing effect of acidic surface groups of a carbonaceous phase.     

植物添加剂降低卷烟烟气自由基研究进展

卷烟烟气自由基是一种典型有害物质,对人体有很大的毒害作用。本文介绍了烟气中有毒成分自由基的形成、性质及对人体的危害,并介绍了对植物添加剂降低清除烟气自由基的研究进展。     

氟磺胺草醚废水的处理研究

氟磺胺草醚废水是一种难降解有机废水,其废水中含有大量的二氯甲烷、二甲亚砜、氯苯等物质。采用吸附的方法进行预处理,结果表明,吸附后COD的去除率高达78%,吸附过程主要考察了吸附时间、活性炭种类、活性炭量对吸附效果的影响,通过多组数据控制参数找出最佳运行参数。在最佳状态下进行电解,考察电解时间对废水生化性的影响,找出最佳预处理的条件。     

Adsorption of toluene onto activated carbons exposed to 100 ppb ozone

The effects of 100 ppb ozone exposure on the adsorption of 1 ppm toluene on activated carbon are presented for dry (less than 5% RH) and humid (55% RH) air. In dry air, the 10% toluene breakthrough times of granular carbon beds exposed to ozone for 208 days are 17% less than those of unexposed carbon beds. At 55% RH, the corresponding reduction in toluene breakthrough time is 78%. For a humid environment with 100 ppb ozone, filter life would be reduced by more than half compared to the expected life based on tests in the absence of ozone. This degradation is attributed to changes in carbon surface chemistry, surface area, and pore volume that occur with relatively brief exposure to the ozone.     

Effect of ZnO loading to activated carbon on Pb(II) adsorption from aqueous solution

The effect of zinc oxide loading to granular activated carbon on Pb(II) adsorption from aqueous solution was studied in comparison with zinc oxide particles and oxidized activated carbon. Cu(II), Cd(II) and nitrobenzene were used as reference adsorbates to investigate the adsorption. The BET surface area and point of zero charge (pH_PZC) in the aqueous solution were measured for the adsorbents. The adsorption isotherms were examined to characterize the adsorption of heavy metals and organic molecules. The heavy metal adsorption was improved by both the zinc oxide loading and the oxidation of activated carbon. In contrast, the adsorption of nitrobenzene was considerably reduced by the oxidation, and slightly decreased by the zinc oxide loading. The zinc oxide loading to the activated carbon was found to be effectively used for the Pb(II) adsorption whereas only a part of surface functional groups was used for the zinc oxide particles and the oxidized activated carbon. From the experimental results, the surface functional groups responsible for the Pb(II) adsorption on the zinc oxide loaded activated carbon were considered to be hydroxyl groups that formed on the oxide, while those on the oxidized activated carbon were considered to be carboxylic groups.     

滤嘴通风对卷烟主流烟气释放量的影响

应用单因素分析法研究了滤嘴通风率对卷烟主流烟气中9种成分释放量的影响。结果表明:随着滤嘴通风率的增大,焦油、烟碱、CO、HCN、氨和苯并[a]芘的释放量呈显著降低趋势,巴豆醛和苯酚释放量呈一定的降低趋势,而NNK(尼古丁代谢衍生物)的释放量变化不显著;滤嘴通风率与NNK,苯并[a]芘及HCN单位焦油释放量呈显著相关关系,但与巴豆醛、苯酚和氨的单位焦油释放量不相关。