一种测量吸附剂甲醛吸附性能的新方法

在人造建材内添加高性能吸附剂可降低其甲醛散发。本文发展了一种简单的密闭舱法来测试吸附剂吸附甲醛的分离系数K,可为建材中添加合适的高性能吸附剂提供依据。基于此方法,本文测试了活性炭纤维(ACF)和浸渍高锰酸钾的氧化铝(PIA)两种常见吸附剂的K值。结果表明:在研究的平衡浓度范围内(即5 mg/m~3),两种吸附剂的吸附特性符合亨利定律;PIA吸附甲醛的性能优于ACF,可添加在建材中降低甲醛散发。     

多孔硅胶固化吸附剂吸附性能研究

固化吸附剂是提高吸附剂传热性能的重要方式,但是恶化了吸附剂的传质性能。以羧甲基纤维素(CMC)为黏结剂的多孔固化吸附剂利用CMC部分分解,在层间产生丰富的孔道,降低了吸附剂的传质阻力,具有强化吸附剂传质作用。本文对多孔硅胶固化吸附剂开展了容量法吸附性能评价、压汞法测试以及吸附性能计算,结果表明,多孔固化吸附剂层内存在一定量的大孔,改善了吸附剂传质特性;根据细孔扩散和表面扩散的计算方法,分别获得多孔硅胶固化吸附剂的细孔扩散系数和表面扩散系数。     

改性生物质活性焦碳管吸附剂汞吸附性能实验研究

本文以稻壳为原料,经H_3PO_4活化、HBr溶液改性,制得用于吸附管离线采样法测试烟气汞浓度的颗粒活性炭,其BET比表面积达853.017 m~2/g,超过一种商业活性炭。将其制成碳吸附管后,在模拟烟气固定床试验装置上进行碳管法烟气汞浓度测试。结果表明:改性稻壳基颗粒活性炭的汞吸附性能与商业活性炭相当,碳吸附管的第二段汞穿透率RB5%,测量相对误差满足EPA 30B碳管法测量精度要求,本文研制的活化改性稻壳焦颗粒活性炭可作为碳管汞吸附剂用于燃煤锅炉烟气中汞的检测分析。     

液氮温区气体吸附试验装置的研制及测试结果分析

液氮温区吸附器设计制造的关键是准确求解吸附剂在一定工况下对吸附质的动态吸附量。由于工况的复杂性,吸附剂和吸附质的多样性使得实际动态吸附值与计算值有偏差,还有些动态吸附值难以查询。介绍了动态吸附值测试的实验装置的设计、研制过程,并对实际测试结果进行了分析。     

吸附剂吸附特性的实验研究

实验研究了变压吸附系统中不同吸附剂的吸附特性,分析了不同因素对各种吸附剂吸附性能的影响,包括吸附温度、吸附压力和时间。研究发现不同吸附剂的吸附效率在不同的时间段显现出相反情况,提出了吸附剂的选择与运用需要考虑切换时间这一观点。最后得出了本试验装置的最佳压力与温度的变化范围(0.2MPa-0.25MPa,20℃-30℃)。     

质子化改性壳聚糖吸附硫酸根行为及其光谱分析

壳聚糖(CTS)具有活性基团氨基和羟基,可用作吸附剂。在酸性介质中其氨基容易质子化形成氨基正离子,具有吸附阴离子的能力,同时也导致吸附剂的溶解流失;进行交联处理可提高吸附剂的酸稳定性,但也导致吸附性能的下降。因此可进行氨基保护后进行交联以改善其酸溶液稳定性,再脱去氨基保护剂进行质子化处理以获得较好的对阴离子的吸附性能。以甲醛为氨基保护剂,戊二醛为交联剂,通过反相悬浮法制得交联壳聚糖(CCTS),对其进行质子化制得质子化改性壳聚糖吸附剂(P-CCTS),并首次将该吸附剂用于处理水溶液中的硫酸根离子。通过静态吸附实验,考察了质子化改性壳聚糖对硫酸根的吸附性能;利用X射线能谱元素分析(EDS)和红外光谱分析(FTIR)对该吸附剂的制备以及对硫酸根离子的吸附过程进行了表征,探索了交联反应和吸附反应的发生机理。实验结果表明：质子化改性壳聚糖吸附剂与交联壳聚糖相比,其对硫酸根离子的吸附性能提高了约10倍;甲醛、戊二醛的醛基与壳聚糖的交联反应主要发生在的氨基(—NH₂)和部分一级羟基(C₆—OH)上;质子化过程中交联壳聚糖的氨基与质子化剂形成了氯化壳聚糖氨盐;对硫酸根离子的吸附则主要是质子化氨基上氯离子与硫酸根离子的交换作用。     

氯化锶-膨胀石墨吸附制冰系统固化复合吸附剂性能

本文用质量分数占35%的膨胀石墨做添加剂并采用压块技术配置了氯化锶-膨胀石墨固化复合吸附剂,测试了该吸附剂在蒸发温度从-25～-5℃变化范围下的吸附制冷特性、吸附速率、最大吸附量以及最大转化率等相关参数,其中单位质量吸附剂最大吸附量可达0.7 kg/kg(NH_3/salt)。同时,通过计算分析,确定采用该复合吸附剂的吸附制冰系统平均SCP可达738 W/kg,COP可达0.435。     

氧化石墨烯(GO)及复合物制备及其对汞吸附特性的研究

以石墨粉(G)为原料,通过化学方法制备了氧化石墨烯(GO)、纳米Fe_3O_4负载石墨烯复合材料(MGO)、纳米Ag颗粒修饰磁性氧化石墨烯(GO-Ag/MGO-Ag)四种吸附材料,对材料进行了表征并考察了氧化石墨烯及其复合物对烟气中汞的吸附作用。研究表明四种石墨烯基吸附剂可被成功合成和表征;GO在100-150℃时对Hg~0表现出优异的吸附性能,Ag-NPs修饰GO能有效提升吸附剂对汞的吸附能力,MGO-Ag复合吸附剂对汞的吸附能力最佳;MGOAg在150~200℃时表现出优异的汞吸附能力,在反复循环之后吸附性能几乎不变;以MGO-Ag为代表的可再生磁性石墨烯基复合吸附剂在中低温条件下对Hg~0具有优异的吸附性能,且能有效与飞灰进行分离,具有良好的工业应用前景。     

沸石分子筛/泡沫铝复合吸附剂及其吸附制冷性能

本文提出了一种强化传热传质的沸石分子筛／泡沫铝复合吸附剂及其制备方法,用HotDisk热物性测量仪测量了其导热系数为2．89 W／mK。基于平衡吸附对其吸附制冷的性能进行了理论计算,并与沸石分子筛-水吸附制冷系统性能进行了比较。结果表明虽然由于金属铝的热容影响,使系统COP下降,但制冷功率有大幅提高。     

纸张与PVC衍生吸附剂的制备及其脱汞性能研究

本文以纸张为碳基体,PVC为活性氯前驱体,利用两者热交互作用制备含氯吸附剂,研究了不同温度、不同混合比例、不同气氛、不同停留时间下热解制备的吸附剂的汞脱除效果。实验表明,纸张与PVC有很明显的交互作用,从而在吸附剂表面形成活性Cl原子。原料中PVC的加入明显增强了吸附剂的吸附性能,在110℃和150℃下对汞的吸附性能显著提高,且在150℃下,CO_2比N_2气氛下制备的吸附剂吸附性能更好。研究表明废弃物衍生汞吸附剂是一种可行的方案。     

Effects of activated carbon properties on the adsorption of naphthalene from aqueous solutions

The aim of this work was to investigate the role of porous and chemical heterogeneities of activated carbons in the adsorption of naphthalene from aqueous media. A commercially available activated carbon was used as the adsorbent, and its surface heterogeneity was systematically altered by heat treatment at 450 and 850 °C, obtaining a series of carbons with various oxygen contents and similar surface functionalities. The results confirmed that the adsorption of naphthalene depends strongly on the pore size distribution of the adsorbent, particularly narrow microporosity. Moreover, oxygen functionalities reduced the accessibility and affinity of naphthalene to the inner pore structure via formation of hydration clusters. Consequently, the hydrophobic/hydrophilic character of the adsorbent is important, since it dominates the competitive adsorption of water. Adsorbents with a high non-polar character (i.e., low oxygen content) have proven to be more efficient for naphthalene adsorption.     

非平衡吸附与固体吸附制冷循环特性研究

在固体吸附制冷循环中，实际的吸附（解吸）过程都是非平衡吸附过程，这使实际的吸附制冷循环与理论上的平衡吸附组成的制冷循环有差距。本文比较了不同表面扩散速度系数下吸附反应器在运行中的内部温度场和吸附率分布，并从热力学循环的角度进行了分析讨论，文中分析及结论有助于深入认识吸附反应器在制冷循环中工作特性。     

First-principle study on the structural and electronic properties of H2S and SO2 adsorption on Pd-doped MoS2 monolayer

The partial discharge in SF₆-insulated equipment produces characteristic decomposition products: SO₂ and H₂S. The characteristic decomposition products vastly speed up the process of discharge faults. Based on density functional theory (DFT) calculation, single layer Pd-doped MoS₂ (Pd-MoS₂) is adopted as the adsorbent to adsorb SO₂ and H₂S to ensure the operational stability of SF₆-insulated equipment. The adsorption energy, charge transfer and structure parameters of SF₆, H₂S, and SO₂ adsorption on the Pd-MoS₂ monolayer are analysed to find the most stable adsorption structure. The molecular orbital theory, total density of states and partial density of states are studied to analyse the adsorption mechanism. The results show that Pd-MoS₂ adsorbent possesses high catalytic activity and excellent adsorption performance to H₂S and SO₂ by strong chemical adsorption. This study is of great significance to ensure the operational stability of SF6-insulated equipment by removing these characteristic decomposition products.     

吸附制冷间歇运行及起动的数值模拟

本文对吸附制冷系统中吸附器内的非均匀的温度场和非均匀的吸附浓度场之间的相互作用关系,以及吸附器在工作暂停时段以及重新启动后吸附器内的工作状况进行了数值模拟,并分析了在不同时刻系统暂停对系统运行循环的影响。结果表明,由于正常运行时,吸附剂内温度场和浓度场都存在很大的梯度,因此,停机过程中,吸附剂内仍然持续着温度和浓度的迁移过程,再重新启动后,其循环的特征参数已与停机时有一定区别,区别大小与循环中的停机时刻以及停机时间长短有关。     

具有非平衡吸附特征的吸附床传热特性研究

吸附床是固体吸附制冷系统的关键部件,对于连续回热等快速进行的吸附制冷循环,吸附床内温度的变化及其压力交变对吸附特性的影响不可忽视。本文对吸附床在吸附、解吸过程中的温度场和吸附率分布进行了模拟计算,并将其与采用平衡吸附模型的计算结果进行了比较,文中比较及结论有助于深入认识吸附床在制冷循环中工作特性,并为吸附床的设计提供参考依据。     

Bio-Adsorbent from Carboxymethyl Cellulose and Tannin for Dye Adsorption

A bio-adsorbent was prepared by the crosslinking reaction of a tannin based phenolic resin and carboxymethyl cellulose with epichlorohydrin as crosslinker. The water absorption ratio of the adsorbent decreased due to the introduction of the phenolic resin based on tannin but the adsorption properties of the adsorbent for methylene blue were improved due to the introduction of the phenolic hydroxyl groups from the tannin in comparison with the carboxymethyl cellulose based adsorbent cross-linked with epichlorohydrin. The maximum adsorption capacity of the adsorbent for methylene blue was 1300mg/g and the adsorption process for methylene blue was exothermic. The adsorption ratio of the adsorbent for methylene blue was over 98% for an adsorbent dosage of 2.5 g/L when the concentration of methylene blue in solution was lower than 2000mg/L. The adsorbent can process wastewater containing methylene blue in the pH range of 4–12.     

CuO掺杂C3N对C5F10O分解组分吸附性能的第一性原理研究

全氟五碳酮（C5F10O）作为可替代SF6的新型环保绝缘气体已被投入到实际应用中. 在绝缘设备内部不可避免的会发生局部放电等故障,造成C5F10O绝缘气体分解产生弱绝缘性能甚至剧毒的分解组分,为保证绝缘设备的安全运行,在不影响气敏传感器正常检测绝缘设备内部故障的情况下,需对这些分解组分进行有选择地吸附去除. 新型类石墨烯C3N材料在气体吸附领域具有良好的应用前景,文中基于第一性原理计算了CuO分子掺杂C3N对主要分解组分CF4、C2F6及剧毒产物CF2O、HF的吸附过程,计算并分析了各分解组分吸附时的吸附能、态密度、电荷转移量、差分电荷密度以及不同环境温度下的恢复时间. 结果表明,CuO-C3N对HF表现出良好的吸附性,CF2O次之,但其无法吸附CF4与C2F6,因此CuO-C3N可以作为一种高性能的气体吸附剂对C5F10O绝缘设备内的剧毒分解组分HF进行吸附去除.     

Foundations of the fluctuation theory of adsorption on microcrystalline particles

Fundamentals of the equilibrium fluctuation theory of adsorption of molecules on microcrystalline particles taking into account the atomic structure of nonuniform surfaces were developed. The importance of taking into account the discrete character of adsorption centers in constructing adsorption isotherm equations was demonstrated. This changes the type of the mathematical apparatus in the search for a maximum distribution function term in a grand canonical ensemble: instead of differential derivatives, symmetrized difference derivatives should be used. The fluctuation theory of adsorption was generalized to ideal multicomponent mixtures of molecules. Adsorption isotherm equations for multicomponent mixtures on uniform and nonuniform surfaces taking into account limited sizes of the surface of various microcrystal faces and fluctuation contributions were obtained. The equations describe the influence of equilibrium fluctuations on adsorption isotherms for adsorbent particles of all sizes, from nanometric to macroscopic. An analysis of the equations showed that the influence of fluctuations was strongest at low coverages for each microcrystal face. The simplest case of taking fluctuations into account in the presence of contributions of lateral interactions in the mean field approximation was discussed.     

Highly efficient simultaneous ultrasonic-assisted adsorption of Pb(II), Cd(II), Ni(II) and Cu (II) ions from aqueous solutions by graphene oxide modified with 2,2′-dipyridylamine: Central composite design optimization

In present work, a graphene oxide chemically modified with 2,2′-dipyridylamine (GO-DPA), was synthesized by simple, fast and low-cost process for the simultaneous adsorption of four toxic heavy metals, Pb(II), Cd(II), Ni(II) and Cu(II), from aqueous solutions. The synthesized adsorbent was characterized by FT-IR, XRD, XPS, SEM and AFM measurements. The effects of variables such as pH solution, initial ion concentrations, adsorbent dosage and sonicating time were investigated on adsorption efficiency by rotatable central composite design. The optimum conditions, specified as 8 mg of adsorbent, 20 mg L⁻¹ of each ion at pH 5 and short time of 4 min led to the achievement of a high adsorption capacities. Ultrasonic power had important role in shortening the adsorption time of ions by enhancing the dispersion of adsorbent in solution. The adsorption kinetic studies and equilibrium isotherms for evaluating the mechanism of adsorption process showed a good fit to the pseudo-second order and Langmuir model, respectively. The maximum adsorption capacities (Q_m) of this adsorbent were 369.749, 257.201, 180.893 and 358.824 mg g⁻¹ for lead, cadmium, nickel and copper ions, respectively. The removal performance of adsorbent on the real wastewater samples also showed the feasibility of adsorbent for applying in industrial purposes.     

污泥吸附剂的制备及其光谱性能研究

以城市和石化污水厂生化活性污泥及剩余污泥为原料,采用热解法制备烟气脱硫吸附剂,并与商品活性炭对比进行了孔结构、扫描电镜、X射线衍射、热分析及元素分析性质表征,利用傅里叶红外光谱法研究污泥吸附剂在SO₂-O₂-N₂及SO₂-O₂-H₂O_(g)-N₂体系的吸附机理。结果表明城市污水厂剩余污泥制备的吸附剂脱硫性能较好,其次为石化活性污泥,生化活性污泥吸附剂脱硫性能较差,剩余污泥制备的吸附剂脱硫率略低于商品活性炭。SO₂-O₂-N₂体系吸附机理主要为物理吸附,SO₂-O₂-H₂O_(g)-N₂体系SO₂发生了催化氧化,以化学吸附为主。吸附过程中起吸附作用的主要是微孔结构。