海藻酸钠/壳聚糖复合纸的制备及性能研究

目的研究海藻酸钠/壳聚糖对纸张的增强作用及制得复合纸对色素及金属离子的等温吸附特性,实现海藻酸钠/壳聚糖在纸张中的复合应用。方法依次采用阴离子多糖海藻酸钠、阳离子多糖壳聚糖季铵盐对纤维素滤纸进行浸渍干燥处理。结果相比滤纸基材,复合纸的抗张强度提高了119%,耐破度提高了105%。红外检测显示,复合纸的氢键吸收峰变宽、变高,说明材料中的氢键结合力变强。吸附等温线拟合显示,制得的复合纸对甲基橙色素具有较好的吸收性能。对Cu2+的吸附符合Langmuir及Freundlich模型方程,属于单分子层吸附。结论海藻酸钠/壳聚糖可用于制备具有一定吸附性能的复合纸,并能增强其力学性能。     

椰壳类活性炭孔隙结构对苯并噻吩脱附活化能的影响

主要研究活性炭孔隙结构对苯并噻吩脱附活化能及吸附性能的影响.使用ASAP 2010测定了3种椰壳制活性炭SY-6、SY-13和SY-19的BET比表面及其孔隙结构,采用程序升温脱附技术(TPD)测定了苯并噻吩在3种活性炭上的脱附活化能,用静态吸附法进行了苯并噻吩在不同活性炭上的吸附等温线,并讨论了活性炭孔隙结构对苯并噻吩脱附活化能及吸附性能的影响.结果表明,3种活性炭SY-6、SY-13和SY-19的比表面积分别为1106、1070和689m2/g,其平均孔径分别为1.96、2.58和2.16nm.苯并噻吩在SY-6、SY-19和SY-13活性炭上的脱附活化能依次为58.84、53.02和42.57kJ/mol,3种活性炭对苯并噻吩吸附容量的大小依次为SY-6＞SY-19＞SY-13.活性炭平均孔径越小,其表面对苯并噻吩的作用力越大,苯并噻吩在其表面上的脱附活化能越大.Freundlich模型能够较好的来描述苯并噻吩在活性炭上的吸附.     

锌掺杂硅胶吸附材料的制备与性能研究

以陶瓷纤维纸为基材,经水玻璃浸渍及锌盐的酸性水解沉积,制备出新型高吸附性能锌掺杂硅胶吸附材料.用扫描电子显微镜、红外光谱仪和比表面积分析仪等对产物进行了表征,并考察了浸渍时间、浸渍温度、锌盐含量、外加酸含量以及反应温度等制备条件对材料吸附水性能的影响.SEM结果表明,制得的吸附材料中,锌掺杂硅胶微粒较均匀地分布在陶瓷纤...     

硅胶干燥剂涂层等温除湿传质特性的数值模拟研究

吸附除湿循环存在复杂的热质耦合传递现象，其中吸附阶段干燥剂释放的吸附热会导致除湿性能下降，而理想等温除湿可有效消除吸附热影响。为研究硅胶干燥剂涂层等温除湿传质特性，本文将热质传递解耦，依托实验验证的二维共轭传热传质数值模型，模拟研究决定气固侧传质阻力的两个关键因素——空气流速和干燥剂层厚度对传质特性的影响规律。结果表明：空气流速的增加能够强化气侧传质，因而固侧传质阻力对总传质制约作用增强，吸/脱附过程Sh和Bi_m均增大，而干燥剂层厚度增加时，固侧传质阻力增大，吸/脱附过程Sh减小、Bi_m增加。特别指出，干燥剂涂层除湿过程数值建模通常需要同时考虑气固侧传质阻力影响。     

转轮除湿空调系统及吸附剂再生特性研究进展

转轮除湿空调系统可实现温湿独立控制,与传统空调相比具有舒适、节能、环保等优点。本文阐述了转轮除湿空调系统及其吸附剂再生特性的研究进展,包括转轮除湿空调系统形式及其特性、转轮除湿性能和吸附剂再生方式及再生特性等内容。最后,指出了目前转轮除湿空调系统的研究不足,并对转轮除湿空调系统进一步研究方向提出了建议。     

PTFE表面改性及其对油污的吸/脱附性能

采用表面改性的方法对聚四氟乙烯纤维(PTFE)滤料进行亲水疏油改性,分别利用傅里叶红外光谱仪和全自动视频微观接触角测量仪对PTFE表面官能团和纤维亲水性进行测试。研究了改性及未改性PTFE纤维对油污的吸/脱附性能,结果表明油污浓度、时间、温度、pH值对吸/脱附性能有显著的影响。改性及未改性PTFE纤维的吸附量最大的吸附条件是:40℃、pH=3、油浓度为100mg/L时,最大吸附量分别为65.00、89.18mg/g。     

一种新型前置预冷转轮除湿复合空调系统

提出了一种新型前置预冷转轮除湿复合空调系统,除湿转轮采用第Ⅲ类吸湿剂。对利用该系统用于独立新风系统的可行性进行了性能分析。结果表明,在华南地区夏季两种典型工况下,该转轮除湿采用再生温度为45℃就可以满足室内湿度的要求;对于相对湿度为90％且温度低于36.7℃的高温高湿工况,该转轮除湿采用再生温度为60℃仍可以满足室内湿度的要求;但与除湿转轮采用第Ⅰ类或第Ⅱ类吸湿剂相比,不能达到更低的送风露点温度。因此,该系统方案所需再生温度较低,较适用于高品质/舒适性空调方面。     

硅胶转轮除湿机的试制

应国内某些行业需要生产环境空气温度18～25℃、相对湿度2～5%、空气露点温度低于-40℃的低露点环境除湿设备的要求,锡山市西漳除湿设备厂在生产能处理低温低湿空气的氯化锂转轮除湿机的经验基础上,通过对硅胶吸湿剂物理性能和吸湿原理的理解,试制成硅胶吸湿纸,并对硅胶吸湿纸进行了动态和静态的小样试验,再对硅胶转轮除湿机的转芯结构尺寸、转速、除湿量、运行参数进行确定.对转芯增设了冷却区.硅胶转轮以设定的转速连续旋转,除湿,再生,冷却三区工作同时进行.采用冷冻除湿和硅胶吸附干燥除湿相结合的系统,将空气处理到含湿量＜0.4g/kg(( ))的需要值,空气露点温度达到-46℃.填补了我国不能生产低露点环境除湿设备的空白.     

办公废纸脱墨中表面活性剂吸附作用研究

目的基于表面活性剂与油墨及废纸纤维之间的交互作用对于浮选脱墨的重要意义,研究办公废纸脱墨中表面活性剂的吸附行为。方法选取十二烷基苯磺酸钠(C12H25Na O4S,SDBS)和全氟辛酸钠(SPFOF15Na O2,SPFO)等2种常用的阴离子表面活性剂,以及疏水性炭黑和亲水性办公室废纸纤维等2种典型物质,通过润湿实验,研究它们在浮选脱墨时的吸附性能。同时,通过在表面活性剂中添加钙,进一步探索钙和表面活性剂的结合作用对炭黑和废纸纤维表面吸附性的影响。结果在不添加钙形成聚集时,随着SDBS或SPFO平衡浓度的增加,炭黑或废纸纸纤维表面的SDBS或SPFO吸附密度将增加,SPFO在废纸纤维和炭黑表面及SDBS在纸纤维表面能形成双分子层吸附,但SDBS在碳黑表面是单层吸附;在表面活性剂溶液中添加钙时,随着钙离子浓度的增加,炭黑表面的SDBS或SPFO吸附均增加,当溶液p H值为9时,纸纤维上SPFO最大吸附密度高于SDBS,在纸纤维上的SPFO吸附存在"钙排斥"效应;炭黑上的SDBS吸附性与p H值无关。结论钙在办公废纸脱墨中是有效的催化剂,可以与阴离子表面活性剂产生协同吸附作用,提高废纸脱墨效果。     

聚天冬氨酸/木质纤维素水凝胶对Pb(Ⅱ)的吸附及脱附性能

以聚天冬氨酸(PASP)与木质纤维素(LNC)水溶液聚合法制备出的聚天冬氨酸/木质纤维素水凝胶(PASP/LNC)为吸附剂,对Pb(Ⅱ)进行吸附及脱附实验,研究溶液的初始离子浓度、pH值、吸附时间和吸附温度对溶液中Pb(Ⅱ)吸附量的影响。结果表明,溶液中Pb(Ⅱ)初始离子浓度为0.04 mol/L,溶液pH值为5.5,吸附时间为120 min,吸附温度为30℃时,PASP/LNC水凝胶对Pb(Ⅱ)的吸附量达到最大为972.35 mg/g。吸附过程符合准二级动力学模型,吸附等温线符合Langmuir模型。采用X射线衍射分析、比表面积和平均孔径分析、扫描电镜、傅里叶变换红外光谱分析PASP/LNC水凝胶的结构和吸附机理。使用HNO_3对PASP/LNC进行脱附实验。结果表明,HNO_3浓度为0.04 mol/L,脱附温度为30℃,脱附时间达到60 min时,最大脱附量为928.36 mg/g。吸附/脱附循环实验表明,PASP/LNC水凝胶重复使用4次后吸附量仍较高,是一种可重复使用的高效吸附材料。     

Theoretical and experimental studies on isothermal adsorption and desorption characteristics of a desiccant-coated heat exchanger

Dynamic characteristics of desiccant–coated heat exchangers (DCHEs) were experimentally measured by wind tunnel. The surface of the DCHE was coated with polymer sorbent desiccant. The isothermal adsorption and desorption experiments were conducted under the condition where the temperatures of the air and brine passing through the DCHE were identical.The experimental results were compared to that obtained from theoretical calculations. A diffusion model predicting the distribution of moisture concentration and temperature in the desiccant layer was introduced. The equivalent diffusion coefficient of the water inside the desiccant layer was determined from the experimental results.The adsorption and desorption speeds were at the maximum values at the beginning of the sorption processes, and then they gradually decreased. The equivalent diffusion coefficient was dependent on the temperature. Assuming the temperature dependence of the diffusion coefficient, the calculated sorption performance correlated well with that obtained from the experimental results.     

日本对调湿材料的研究及应用

在介绍调湿材料调节空气湿度原理的基础上，评述了日本学者关于调湿材料调湿特性好坏的四种观点，着重报道了日本近二十几年来研究开发的四类调湿材料，并对它们的工艺过程，调湿特性和应用概况进行了说明，最后提出了未来调湿材料的研究方向。     

离子改性的聚丙烯酸除湿换热器系统性能研究

干燥剂吸附性能对除湿换热器系统的除湿性能有重要影响。本文通过改进的ASAP2020气体吸附仪和恒温恒湿箱,先后对Na^+和K^+改性的聚丙烯酸聚合物的水蒸气平衡吸附性能和吸附动力学特性进行了测试研究,并与硅胶相对比。研究结果表明:平衡吸附测试显示Na^+改性的聚丙烯酸在整个相对压力区间性能优于硅胶,K^+改性的在高相对压力区间(>0.8)逊于硅胶;基于Polanyi吸附势理论对干燥剂吸附特征曲线进行拟合,以用于后续的除湿换热器模拟研究;动态吸附性能表明聚丙烯酸干燥剂的吸附速率均低于硅胶,但Na+改性的聚丙烯酸整个吸附过程的动态吸附量仍多于硅胶;通过模拟除湿换热器除湿性能,在ARI summer、ARI humid和上海夏季这3种典型室外工况下,Na^+改性的聚丙烯酸换热器可以从待处理空气中去除更多的水分,较硅胶换热器提升49%~118%,适用于室外湿度较小的气候工况。     

Characterization of desiccant wheels with alternative materials at low regeneration temperatures

A number of new desiccant materials have been proposed which have the potential to improve the performance of desiccant wheels being regenerated at low temperature. Desiccant wheels containing two such desiccant materials (zeolite and superadsorbent polymer) were compared with a conventional silica gel desiccant wheel. The superadsorbent polymer desiccant wheel achieved greater dehumidification than the silica gel wheel when dehumidifying high relative humidity air with low temperature (50 °C) regeneration air. The temperature of dehumidified air exiting the polymer wheel was also lower. The zeolite desiccant wheel was generally less effective at dehumidifying air and had a higher pressure drop.     

Formation of defect-free latex films on porous fiber supports

We present here the creation of a defect-free polyvinylidene chloride barrier layer on the lumen-side of a hollow fiber sorbent. Hollow fiber sorbents have previously been shown to be promising materials for enabling low-cost CO(2) capture, provided a defect-free lumen-side barrier layer can be created. Film experiments examined the effect of drying rate, latex age, substrate porosity (porous vs nonporous), and substrate hydrophobicity/hydrophilicity. Film studies show that in ideal conditions (i.e., slow drying, fresh latex, and smooth nonporous substrate), a defect-free film can be formed, whereas the other permutations of the variables investigated led to defective films. These results were extended to hollow fiber sorbents, and despite using fresh latex and relatively slow drying conditions, a defective lumen-side layer resulted. XRD and DSC indicate that polyvinylidene chloride latex develops crystallinity over time, thereby inhibiting proper film formation as confirmed by SEM and gas permeation. This and other key additional challenges associated with the porous hollow fiber substrate vs the nonporous flat substrate were overcome. By employing a toluene-vapor saturated drying gas (a swelling solvent for polyvinylidene chloride) a defect-free lumen-side barrier layer was created, as investigated by gas and water vapor permeation.     

Electrothermal properties of porous ceramic fiber media containing carbon materials

Electrically regenerable porous ceramic fiber media containing nanoporous carbon from 2.5% to 19.2% have been prepared for adsorption/regeneration system. An experimental apparatus was built for in situ measurement of the sample weight during adsorption and electrothermal desorption of gaseous adsorbates. Adsorption and electrothermal desorption behavior of gaseous adsorbates on carbon contained porous ceramic fiber media was explained by physical and electrothermal properties of these materials measured in this work. In situ thermal desorption and adsorption experiments show that a considerable amount of water vapor is adsorbed on the carbon contained media exposed to ambient air.     

增重法与减重法在不同包装材料中的应用

目的探究基于称重法原理的增重法与减重法在不同包材领域内的应用范围。方法避免人工、环境等引入测试误差导致的对比偏差,采用透湿试验腔内自动称量的智能检测仪器,依据ASTM E96标准方法中的增重法与减重法,测试并比较在不同温湿度实验条件下塑料薄膜、纸铝塑复合膜、人造皮革、无纺布等7种不同材质与阻湿性样品的水蒸气透过率。结果纸铝塑复合膜、人造皮革及无纺布样品分别利用增重法和减重法所测得的水蒸气透过率结果有明显差别,而其余4种样品差值不明显;人造皮革样品的增重法实验结果高于减重法的结果,而纸铝塑复合膜及无纺布这2种样品的结果则相反。结论增重法与减重法在测试水蒸气透过率时并非在任何条件下均适用于所有包装材料,应根据样品的材质、结构、使用环境条件及实际用途等因素合理选用增重法或减重法进行检测。     

Synthesis and humidity control performances of natural opoka based porous calcium silicate hydrate

In this work, a porous calcium silicate hydrate (CSH) humidity control material was prepared by hydrothermal synthesis with opoka (ROP) and slaked lime. The microstructures and humidity control properties of the prepared sample were characterized and analyzed in detail. Results show that CSH possesses plenty of mesoporous structures with the pore size range of 3–20 nm, which are superior to ROP. The maximum moisture adsorption capacity of CSH is about 2–3 times of ROP. The superior humidity control performance of CSH can be attributed to the increase of specific surface area and pore volume and the more reasonable and uniform pore size distribution. Moreover, CSH also exhibits good reusability within three cycles of adsorption/desorption. Furthermore, the synthesized CSH was added to an interior wall coating to test its humidity control performance in practical building materials. The result indicated that the moisture adsorption capacity of the coating with CSH in 24 h at high humidity can reach 110 g/m², and the moisture desorption capacity can also reach 70 g/m². The as received CSH shows excellent humidity control performance and can be used as a smart indoor humidity control material for various construction applications.     

Novel robust cellulose-based foam with pH and light dual-response for oil recovery

We fabricated pH and light dual-responsive adsorption materials which could induce the transition of surface wettability between hydrophobicity and hydrophilicity by using ATRP. The structure and morphology of adsorption materials were confirmed by ATR-FTIR, XPS, TGA and SEM. It showed that the modified cellulose (CE)-based foam was hydrophobic, which can adsorb a range of oils and organic solvents in water under pH = 7.0 or visible light irradiation (λ > 500 nm). Meanwhile, the wettability of robust CE-based foam can convert hydrophobicity into hydrophilicity and underwater oleophobicity under pH = 3.0 or UV irradiation (λ = 365 nm), giving rise to release oils and organic solvents. Most important of all, the adsorption and desorption processes of the modified CE-based foam could be switched by external stimuli. Furthermore, the modified CE-based foam was not damaged and still retained original performance after reversible cycle repeated for many times with variation of surface wettability. In short, it indicates that CE-based foam materials with switchable surface wettability are new responsive absorbent materials and have owned potential application in the treatment of oil recovery.     

Cleanable Air Filter Transferring Moisture and Effectively Capturing PM2.5

The lethal danger of particulate matter (PM) pollution on health leads to the development of challenging individual protection materials that should ideally exhibit a high PM_2.5 purification efficiency, low air resistance, an important moisture‐vapor transmission rate (MVTR), and an easy‐to‐clean property. Herein, a cleanable air filter able to rapidly transfer moisture and efficiently capture PM_2.5 is designed by electrospinning superhydrophilic polyacrylonitrile/silicon‐dioxide fibers as the adsorption–desorption vector for moisture‐vapor, and hydrophobic polyvinylidene fluoride fibers as the repellent components to avoid the formation of capillary water under high humidity. The desorption rate of water molecules increases from 10 to 18 mg min^?1, while the diameters of polyacrylonitrile fibers reduce from 1.02 to 0.14 µm. Significantly, by introducing the hydroxyl on the surface of polyacrylonitrile nanofibers, rapid adsorption–desorption of the water molecules is observed. Moreover, by constructing a hydrophobic to super‐hydrophilic gradient structure, the MVTR increases from 10 346 to 14 066 g m^?2 d^?1. Interestingly, the prepared fibrous membranes is easy to clean. More importantly, benefiting from enhanced slip effect, the resultant fibrous membranes presented a low air resistance of 86 Pa. A field test in Shanghai shows that the air filter maintains stable PM_2.5 purification efficiency of 99.99% at high MVTR during haze event.