Preparation and hygrothermal performance of composite phase change material wallboard with humidity control based on expanded perlite/diatomite/paraffin

Phase change material(PCM)can reduce the indoor temperature fluctuation and humidity control material can adjust relative humidity used in buildings.In this study,a kind of composite phase change material particles(CPCMPs)were prepared by vacuum impregnation method with expanded perlite(EP)as supporting material and paraffin as phase change material.Thus,a PCM plate was fabricated by mould pressing method with CPCMPs and then composite phase change humidity control wallboard(CPCHCW)was prepared by spraying the diatom mud on the surface of PCM plate.The composition,thermophysical properties and microstructure were characterized using X-ray diffraction instrument(XRD),differential scanning calorimeter(DSC)and scanning electron microscope(SEM).Additionally,the hygrothermal performance of CPCHCW was characterized by temperature and humidity collaborative test.The results can be summarized as follows:(1)CPCMPs have suitable phase change parameters with melting/freezing point of 18.23°C/29.42°C and higher latent heat of 54.66 J/g/55.63 J/g;(2)the diatom mud can control the humidity of confined space with a certain volume;(3)the combination of diatom mud and PCM plate in CPCHCW can effectively adjust the indoor temperature and humidity.The above conclusions indicate the potential of CPCHCW in the application of building energy efficiency.

Fabrication, property characterization and thermal performance of composite phase change material plates based on tetradecanol-myristic acid binary eutectic mixture/expanded perlite and expanded vermiculite for building application

A binary eutectic mixture composed of tetradecanol(TD)and myristic acid(MA)was maximally absorbed into the microstructures of expanded perlite(EP)and expanded vermiculite(EVMT),respectively,through a self-made vacuum adsorption roller to prepare phase change material(PCM)particle(PCP).Then EP and EVMT-based composite PCM plates were respectively fabricated through a mold pressing method.The thermal property,chemical stability,microstructure and durability were characterized by differential scanning calorimeter(DSC),Fourier transform infrared spectroscope(FT-IR),scanning electron microscope(SEM)and thermal cycling tests,respectively.The results show that both PCPs have high latent heats with 110 J/g for EP-based PCP and more than 130 J/g for EVMT-based PCP,compact microstructure without PCM leakage,stable chemical property and good durability.The research results have proved the feasibility for the vacuum adsorption roller used in the composite PCM fabrication.Results of thermal storage performance experiment indicate that the fabricated PCM plates have better thermal inertia than common building materials,and the thermal storage performance of PCM plates has nonlinearly changed with outside air velocity and temperature increase.Therefore,PCM plates show a significant potential for the practical application of building thermal storage.

Hydration Heat Effect of Cement Pastes Modified with Hydroxypropyl Methyl Cellulose Ether and Expanded Perlite

Hydration heat effect of cement pastes and mechanism of hydroxypropyl methyl cellulose ether （HPMC） and expanded perlite in cement pastes were studied by means of hydration exothermic rate, hydration heat amount, FTIR and TG-DTG. The results show that HPMC can significantly delay the hydration induction period and acceleration period of cement pastes. As mixing amount increased, hydration induction period of cement pastes enlarged and accelerated period gradually went back. At the same time, the amount of hydration heat gradually decreased. Expanded perlite had worse delay effects and less change of hydration heat amount of cement pastes than HPMC. HPMC changed the structure of C-S-H during cement hydration. The more amount of HPMC, the more obvious effect. However, EXP had little influence on the structure of C-S-H. At the same age, the content of Ca （OH）2 in cement pastes gradually decreased as the mixing amount increase of HPMC and expanded perlite, and had better delay effect than that single-doped with HPMC or expanded perlite when HPMC and expanded nerlite were both dooed in cement pastes.

Sorption Kinetics and Capacity of Composite Materials Made up of Polymeric Fabric and Expanded Perlite for Oil in Water

The oil sorption capacity of composite materials made up of different polymeric fabrics (namely acrylic fabric (AF), polypropylene nonwoven (PP), and silk stocking (SS) as composite out-packing materials) and expanded perlite (EP) was evaluated for oil removal from the water. The effects of sorbent dosage, desorption time, oil amount in the water, and contact time on composite materials sorption were investigated. The results showed that the optimum quantity of EP was between 0.5 g and 1.0 g for 25 cm2 polymeric fabrics bags. Oil removal efficiency for 6 L/m2 of oil amount in the water was 52%-72%, 44%-63%, and 37%-48% for AF, PP, and SS composite materials, respectively. Oil/water selectivity analysis of different composite materials showed that AF composite material had a very high degree of hydrophobicity and oil sorption capacity of approximately 10.17 g/g. Both oil sorption kinetics and equilibrium studies were carried out, and the equilibrium process of composite materials was described well by the Langmuir isotherm, and the oil sorption kinetics of composite materials showed good correlation coefficients for the pseudo-second order kinetic model. Intra-particle diffusion studies showed that oil sorption mechanism was controlled by the three processes, involving in external liquid membrane diffusion, surface sorption, and intra-particle diffusion.

Study on Sustained-Release Pesticides Blended with Fosthiazate-Stearic Acid/Expanded Perlite

The low utilization rate of pesticides makes the migration of pesticides in water and soil,which brings great harm to the ecosystem.The development of pesticide carriers with good drug loading capacity and release control abil-ity is an effective method to realize effective utilization of pesticides and reduce pesticide losses.In this work,fosthiazate-stearic acid/expanded perlite sustained-release particles were successfully prepared by vacuum impregnation using expanded perlite(EP)as carrier,fosthiazate(FOS)as model pesticide and stearic acid(SA)as hydrophobic matrix.The structure and morphology of the samples were studied by BET,FT-IR,TGA,XRD,DSC and SEM.The effects of different mass ratios of FOS to SA on loading capacity and release rate at 24 h were investigated.The sustained release behavior of FOS-SA/EP at different temperatures and pH values was investigated by static dialysis bag method.The results showed that FOS and SA were adsorbed in EP pores by physical interaction.With the mass ratios of FOS to SA decreasing from 7:3 to 3:7,the 24 h release rate of FOS-SA/EP decreased from 18.77%to 8.05%,and the drug loading decreased from 461.32 to 130.99 mg/g.FOS-SA/EP showed obvious temperature response at 25℃,30℃ and 35℃,the cumulative release rate(CRR)of 200 h were 33.38%,41.50%and 51.17%,respectively.When pH=5,the CRR of FOS was higher than that of pH=7,and the CRR of FOS for 200 h were 49.01%and 30.12%,respectively.At different temperatures and pH=5,the release mechanism of FOS-SA/EP belongs to the Fickian diffusion mechanism;When pH=7,the diffusion mechanism is dominant,and the dissolution mechanism is complementary.

Preparation of Lightweight Alumina-silica Castables by Replacing Closed-cell Perlite Aggregates with Coal Gangue Ceramsites

Lightweight alumina-silica castables were prepared using closed-cell perlite(2-4 mm),open-cell perlite(4-6 mm)and coal gangue ceramsites(2-5 mm)as aggregates,floating beads(0.3-0.5 mm),sinking beads(0.6-0.8 mm),silica micropowder,α-Al_(2)O_(3) micropowder,zirconia and zircon micropowder as fines,and Secar 71 cement(calcium aluminate cement)as the binder.The effects of the coal gangue ceramsites addition(0,6%,12%,18%and 24%,by mass)on the properties of the as-prepared lightweight alumina-silica castables were investigated.The results show that:(1)the addition of coal gangue ceramsites can reduce the sintering shrinkage of the specimens and help to improve the strength and thermal shock resistance;(2)the samples with the addition of coal gangue ceramsites can produce pores in the matrix of the sintered samples,which provides enough space for the growth of CA6 complex solid solution and expands the irregular lamellar structure;(3)with the addition of coal gangue ceramsites increasing,the linear shrinkage of the samples heat treated at 1000 or 1200℃firstly reduces and then increases,the bulk density increases and the apparent porosity decreases;the cold compression strength and the thermal shock resistance of the specimens heat treated at 1200℃firstly increase and then decrease.Thus,the optimal addition of coal gangue ceramsites is 18%.

Alkali-Silica Reactivity and Strength of Mortars with Expanded Slate, Expanded Glass or Perlite

Lightweight aggregates are increasingly used in concrete construction. They reduce concrete selfweight furnishing a structural advantage. In contrast, the mechanical properties and durability of lightweight concrete can become the governing factor on lightweight aggregate replacement ratios. Alkali-Silica Reactison (ASR) and compressive strength of mortar samples with expanded slate, expanded glass or perlite, covering the spectrum of internal porosity and weight of lightweight aggregates, were evaluated. Scanning electron microscopy was utilized to evaluate the contribution of the aggregates’ porosity and chemical composition in inhibiting ASR. Perlite, owing to its highly porous microstructure and lower matter excelled in ASR expansion while chemical composition and denser microstructure of the heavier expanded slate resulted in more signified late ASR expansion and higher compressive strength. An attempt in visual inspection of ASR attack of alkali metal ions on silica-rich expanded glass using an ultra-accelerated exposure to sodium hydroxide solution was made.

Improvement of Oil/Water Selectivity by Stearic Acid Modified Expanded Perlite for Oil Spill Cleanup

Ecological disasters and economic losses resulting from oil spills have reminded us the necessity for finding an environmentally friendly, cost-effective, and available in large-scale materials to minimize the oil spill effects. The development of high oil/water selectivity mineral sorbent for the removal of oil from the water is of great interest for oil spill cleanup. In this work, highly oil/water selectivity sorbent of expanded perlite modified with stearic acid was prepared by solution-immersion processes, and the characterization of sorbent was analyzed by Fourier transformation infrared (FT-IR) spectroscopy technique. The optimized amount of loaded stearic acid (SA) on the expanded perlite surface was found to be 2.0%. Then the sorption characteristics of unmodified expanded perlite (UMEP) and stearic acid modified expanded perlite (SMEP) were tested. The effects of different particles size, oil/water volume ratio and sorption simulated condition were investigated. It was found that expanded perlite modified with stearic acid could adsorb selectively oil from water in oil/water system. The maximum oil/water sorption ratio of SMEP was 46, which was about 191 times that of UMEP (0.24) in studied experimental range. The FT-IR analysis demonstrated the presence of long-chain alkyl group in the SMEP samples, which played an important role in oil/water selectivity of SMEP samples. The equilibrium were tested with Langmuir and Freundlich isotherm models, and oil sorption process of SMEP showed good correlation with the Langmuir isotherm model.

The development of ultralightweight expanded perlite-based thermal insulation panel using alkali activator solution

The International Energy Agency(IEA)states that global energy consumption will increase by 53%by 2030.Turkey has 70%of the world’s perlite reserves,and in order to reduce energy consumption a thermal insulation panel was developed in Turkey using different particle sizes of expanded perlite(EP).In this study,0–1.18 mm(powder)and 0–3 mm(granular)EP particle sizes were selected,since they have the lowest thermal conductivity coefficients among all the particle sizes.In addition,an alkali activator solution was used as a binder in the mixtures.The alkaline activator solution was obtained by mixing sodium hydroxide solution(6,8,10,and 12 mol·L−1)and sodium silicate(Module 3)at the different ratios of Na2SiO3 to NaOH of 1,1.5,2,and 2.5.This study aimed to experimentally determine the optimum binder and distribution ratio of EP,with the lowest coefficient of thermal conductivity and the lowest density.The lowest thermal conductivity and the lowest density were determined as 0.04919 W·m−1·K−1 and 133.267 kg/m3,respectively,in the sample prepared with 83.33%powder-size EP,6 mol·L−1 sodium hydroxide solution,and ratio of Na2SiO3 to NaOH of 1.5.The density,thermal conductivity,and compressive strength of the sample showed the same trends of behavior when the Na2SiO3 to NaOH ratio was increased.In addition,the highest compressive strength was measured in 12 mol·L−1 NaOH concentration regardless of particle size.In conclusion,the study predicts that the EP-based thermal insulation panel can be used as an insulation material in the construction industry according to the TS825 Thermal Insulation Standard.

Highly efficient enrichment and adsorption of rare earth ions(yttrium(Ⅲ))by recyclable magnetic nitrogen functionalized mesoporous expanded perlite

A magnetic mesoporous expanded perlite-based(EPd-APTES@Fe3 O_(4))composite was designed and synthesized as a novel adsorbent for enrichment of rare earth ions in aqueous solution.Effect of various factors including the pH of solution,contact time and adsorbent dosage on the adsorption behaviors of yttrium(Ⅲ)by the EPd-APTES@Fe3 O_(4) nano-material composites from aqueous solution was investigated.The maximum adsorption capacity of the as-prepared materials for yttrium(Ⅲ)ions was 383.2 mg/g.Among the various isotherm models,the Freundlich isotherm model could well described for the adsorption of the rare ea rth ions at pH 5.5 and 298.15 K.The kinetic analysis indicated that the adsorption process followed the pseudo-second order kinetics model,and the rate-determining step might be chemical adsorption.Thermodynamic parameters declared that the adsorption process was endothermic.In addition,Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and the quantum chemical calculation indicated that the yttrium(Ⅲ)ions were captured on the EPd-APTES@Fe3 O_(4) surface mainly by coordination with functional group of-NH2.More importantly,the adsorption-desorption studies indicated that the EPd-APTES@Fe3 O_(4) nano-material composites had a high stability and good recyclability.

膨胀珍珠岩调控固化淤泥物理-力学性能的方法

疏浚淤泥含水率高导致干化和固化成本过高。充分利用膨胀珍珠岩(expanded perlite,简称EP)的多孔吸水性,局部分离淤泥中的自由水,使其变为不均匀分布,营造泥-水分离的固化环境。试验发现,掺入EP可以有效提高固化淤泥的无侧限抗压强度(unconfined compressive strength,简称UCS),但其掺入方式影响固化强度的增长速率和孔隙分布特征。焖料方式最有利于提升固化效果,即把EP先掺入到淤泥中,混合24 h后再加水泥固化;养护28 d时,焖料试样的强度是直接固化试样(EP掺入后直接加水泥固化)强度的1.56倍,是仅掺入水泥固化试样强度的2.15倍,说明EP营造的局部泥-水分离环境可有效提高固化淤泥的强度。同时,水化热试验结果表明,EP促进了水泥水化作用。EP-淤泥固化土的孔隙分布曲线和表观形貌照片显示,虽然掺入EP引入了气孔,但也为水化产物提供了生长空间,使得淤泥和EP界面形成嵌入式胶结,共同构成固化土骨架。EP调控淤泥含水率属于物理方法,方便快捷,并且EP是高硅轻骨料,与淤泥相容性好,兼具环境友好性。

改性TiO_(2)/膨胀珍珠岩光催化剂对赤潮微藻的抑制

米氏凯伦藻是引发赤潮的经典赤潮微藻,会造成水体环境污染甚至是水中动植物死亡。将膨胀珍珠岩(EP)作为漂浮性载体,采用水热合成法、简易包衣法和海藻酸钠固定法3种方法合成的漂浮性光催化剂,并探究3种方法合成的漂浮性光催化剂对于米氏凯伦藻的抑藻作用。结果表明,水热合成法制备的漂浮式光催化剂对于米氏凯伦藻的抑藻作用最为有效,实验进行4 h后藻类去除率达到80%以上;漂浮式光催化剂作用1 h后米氏凯伦藻体内叶绿素a含量和可溶性蛋白质含量急剧下降,表明米氏凯伦藻的光合系统受到破坏,藻细胞失去了能量来源,而蛋白质含量的降低也使得藻细胞的代谢活力下降。该研究为光催化技术应用于赤潮治理提供了一定的理论依据。

模拟高原环境下敏化方式对乳化炸药爆轰性能的影响研究

为研究高原环境对不同敏化方式乳化炸药的影响程度,选取3种典型的敏化材料制备乳化炸药样品,模拟并对比分析了高原环境(-20℃、约0.05 MPa)储存后乳化炸药的微观结构和爆轰性能变化。结果表明:低温低压下的高原环境主要从加剧破坏乳化体系稳定性与热点分布两方面影响炸药的性能,在该环境下化学敏化炸药相较于物理敏化炸药的析晶程度较低,但热点变化较大,导致爆轰性能下降;物理敏化中,膨胀珍珠岩炸药晶体的生长方式更加复杂,因此更易破乳析晶,储存稳定性与爆轰性能均有明显降低;相对而言,树脂微球炸药在低温低压下的析晶程度与爆轰性能均较稳定。综合上述结果,树脂微球乳化炸药具有更好的高原适应性。

建筑用膨胀珍珠岩的资源特性及研究现状分析

对国内外建筑用膨胀珍珠岩的相关产品标准进行梳理,对膨胀珍珠岩的化学成分、微观结构及亲水机理进行分析,指出保持膨胀珍珠岩优异绝热性能的关键是改变其表层的亲水官能团及微孔结构,总结有机硅憎水剂喷涂、聚合物包覆、SiO2气凝胶填充等膨胀珍珠岩改性方法的机理及研究现状,为相关技术人员生产或使用膨胀珍珠岩提供参考。

MA/HA二元相变保温材料制备及节能效果模拟研究

为促进建筑节能,以肉豆蔻酸(MA)和碳十六酸(HA)制备二元相变材料,以膨胀珍珠岩作为吸附载体,制备一种保温材料,研究其性能。并结合建筑信息模型(BIM)节能模拟,研究该保温材料节能效果。结果表明,当MA和HA质量配比为70∶30,且保温材料中MA-HA二元相变材料质量分数为70%时,保温材料综合性能最佳。此时,MA-HA二元相变材料导热系数为0.254 W/(m·K),熔化温度和熔化潜热分别是35.64℃、123.48 J/g,凝固温度和凝固潜热分别是30.98℃、112.54 J/g。在经过1000次吸放热相变循环后,相变温度变化率不超过5%,相变潜热变化率不超过8%。BIM节能模拟表明,在使用保温材料后,建筑外围护结构能耗降幅超过30%。

膨胀珍珠岩保温板在建筑节能中的应用

文章对膨胀珍珠岩保温板的概念进行阐述,对其建筑行业应用特点进行分析,并提出其在建筑节能中的应用,为建筑行业的节能保温材料的发展提供依据。

石墨为吸波剂水泥基膨胀珍珠岩砂浆吸波性能研究

用石墨粉、闭孔膨胀珍珠岩与硅酸盐水泥等材料,制成具有电磁波吸收功能的砂浆层.应用弓形法对砂浆在2～18GHz吸波性能进行了测试,研究不同石墨含量、不同砂浆厚度与砂浆吸波性能的关系.当砂浆层体积中含有30%的膨胀珍珠岩,含有200目(mesh number)石墨粉含量为20%wt时,比含量15%和25%吸波效果好;粒径为200目的石墨粉含量为20%wt时,厚度由1cm变为3cm时,吸收峰增多由2个变为6个,吸收频带增宽且向低频移动,在2～3GHz间吸波效果较差;在3～18GHz间,最大反射率为-3dB,最小吸收峰反射率达-27dB.吸波砂浆层上下界面的反射波干涉相消是随着厚度增加吸收峰增多且向低频移动的原因.

以膨胀珍珠岩为载体的漂浮型TiO_2光催化剂降解水面浮油

以膨胀珍珠岩为载体制备了漂浮负载型TiO2 光催化剂 ,并对制备催化剂的工艺条件及水面浮油的光催化降解过程进行了初步研究 .通过扫描电镜分析及BET比表面积和TiO2 负载量测定 ,对影响负载型光催化剂漂浮性能的因素进行了分析 .以癸烷为水面模拟污染物 ,考察了其在日光照射下的降解效率 .用气相色谱法测定了经不同时间光照后癸烷的残留量 ,经 7h光照后能降解癸烷 95 %以上 .实验结果表明 ,以膨胀珍珠岩为载体 ,可制得能长期漂浮于水面的负载型TiO2 光催化剂 ,通过浮油富集和光催化降解机制可对水面浮油进行有效的治理 .

基于科式芽孢杆菌矿化沉积的混凝土裂缝自修复性能试验研究

混凝土材料具有脆性大、抗拉强度较低等特点,导致其内部或表面难以避免出现微裂缝。基于微生物矿化沉积的裂缝自修复技术能够有效地实现混凝土裂缝的自诊断和自修复。以具有嗜碱特性的科式芽孢杆菌为自修复剂,以膨胀珍珠岩为修复剂载体,研制出一种新型裂缝自修复混凝土。分别对普通混凝土、采用直接掺菌的混凝土和研制的自修复混凝土的裂缝自修复能力进行试验研究。试验结果表明,在裂缝修复早期,裂缝内表面未水化胶凝材料的水化反应致使裂缝宽度小于0.2 mm的普通混凝土试件具有较好的自修复能力;随着裂缝修复时间的增长,基于科式芽孢杆菌矿化沉积的混凝土试件具有更优异的自修复能力,水中养护28 d后研制的自修复混凝土最大修复裂缝宽度可达0.56 mm。研究结果可为混凝土裂缝自修复技术研究提供技术支持和依据。

定形相变储能建筑材料的制备与热性能研究

采用真空浸渗的方法,将棕榈酸和十六醇的低共熔物(PA-HD)与膨胀珍珠岩(EP)结合,制备一种新型定形相变材料(PA-HD/EP)。环境扫描电子显微镜测试显示相变材料PA-HD进入到珍珠岩的孔道结构中。棕榈酸和十六醇的低共熔物在膨胀珍珠岩的最佳浸渗量为58.0%(质量分数,下同),在此浸渗量下,即使是没有进行包覆,PA-HD也不会在发生相变时从EP中渗漏。差示扫描量热仪测试获得PA-HD/EP的熔点为41.49℃,相变焓值为122.9J/g。通过在PA-HD/EP中添加10%石墨,改善材料的导热性能。该复合相变材料可以很好地与普通建筑材料进行结合,进一步制备成具有温度调节功能的建筑材料。