相变微胶囊型吸热剂MPCM-2的制备及其控热效果

以十二水合磷酸氢二钠为芯材,乙基纤维素为壁材,采用原位聚合工艺制备了相变微胶囊型吸热剂MPCM-2,其结构和性能经IR、 DSC、TG和粒度分析表征。结果表明:MPCM-2的相变温度为43.34和58.77℃,总相变焓值为144.82 J·g^(-1),包裹率为67.5%; MPCM颗粒中径为57.26μm,同时,MPCM-2应用于深水固井水泥浆体系可实现对水化热及水化温升的有效控制。

氯化钠吸热条件下的纳米硅制备及其电化学性能

硅因其理论容量高、资源丰富以及对环境友好等优点,成为最有应用前景的下一代锂离子电池负极材料之一。然而,由于生产工艺复杂、成本高昂,使得纳米级硅材料的制备受到限制。采用镁粉和气相二氧化硅作为还原剂和硅源,并在制备过程中巧妙地引入氯化钠作为吸热剂用以吸收镁热还原过程放出的热量,成功制备出平均粒径约25 nm的纳米硅,纳米硅的收率达82%。所制备的纳米硅晶粒细小,有优良的电化学性能,首次脱锂比容量超过1875 m Ah·g^(–1),首次库伦效率高达85%。以0.6 A·g^(–1)电流密度循环50次后,脱锂比容量仍可保持1007 m Ah·g^(–1)。

干磨砂纸超涂层的研究

为研制适用于软质材料磨削的干磨砂纸 ,通过涂覆特殊的防堵塞材料 ,利用吸热剂的相转变原理 ,研制了干磨砂纸超涂层浆料。通过对木材的磨削实验 ,研究表明复合吸热剂比单一吸热剂效果更好 ,具有更宽的吸热区域。复合吸热剂 ( 1#:2 #=5 :5 )用量在 3 2 %左右时 ,总磨削量达到 2 7g ,差热分析DTA证明其吸热峰顶温度为 14 8℃。采用聚氨酯乳胶作为超涂层浆料胶粘剂 ,以三聚氰胺—甲醛树脂为交联剂。研究发现当胶膜铅笔硬度为 3H～ 4H ,用量 2 7%左右时 ,磨削量最大。同时研究表明滑石粉作为润滑剂 ,用量为 2 7%最好。采用该超涂层浆料制备的超涂层干磨砂纸 ,其磨削量达到 2 7g ,比未涂上超涂层的砂纸磨削量提高 10 7% ,比进口超涂层砂纸磨削量提高 8%。

Adsorption onto Activated Carbon Fiber Cloth and Electrothermal Desorption of Volatile Organic Compound(VOCs):A Specific Review

A general research program, focusing on activated carbon fiber cloths （ACFC） and felt for environmental protection was performed. The objectives were multiple： （i） a better understanding of the adsorption mecha- nisms of these kinds of materials; （ii） the specification and optimization of new processes using these adsorbents; （iii） the modeling of the adsorption of organic pollutants using both the usual and original approaches; （iv） applications of ACFC in industrial processes. The general question was： how can activated carbon fiber cloths and felts be used in air treatment processes for the protection of environment. In order to provide an answer, different approaches were adopted. The materials （ACFC） were characterized in terms of macro structure and internal porosity. Specific studies were performed to get the air flow pattern through the fabrics. Head loss data were generated and modeled as a fi.mction of air velocity. The performances of ACF to remove volatile organic compounds （VOCs） were approached with the adsorption isotherms and breakthrough curves in various operating conditions. Regenera- tion by Joule effect shows a homogenous heating of adsorber modules with rolled or pleated layers. Examples of industrial developments were presented showing an interesting technology for the removal of VOCs, such as dichloromethane, benzene, isopropyl alcohol and toluene, alone or in a complex mixture.

Adsorption of Acetanilide Herbicides on Soil and Its Components: Ⅳ. Sorption of Acetanilide Herbicides on Soils and its Correlation with Soil Properties

Sorption of acetanilide herbicides, metolachlor, acetochlor, pretilachlor and butachlor on eight soils with various physical and chemical properties was studied. The adsorption isotherms could fit Freundich equation well (r 2 ≥0.91) and the adsorption extents increased in the order: metolachlor < acetochlor < pratilachlor < butachlor. The product of Freundlich adsorption constants, Kf (1/n), showed to have a good correlation with organic matter content (OM) of soils for each of these herbicides, suggesting that OM is the primary factor dominating in the adsorption process of these asetanilide herbicides. Multivariant correlation regression between Kf (1/n) and two factors, water solubility (S.) of herbicides and OM, was also performed. Kf(1/n) correlated with 1/S. and OM/S. well, showing that high S. corresponds to a weak tendency to adsorb on soils. Infrared (IR) spectra and electron spin resonance (ESR) parameters confirmed that multifunctional H-bonds and charge-transfer bonds were the main adsorption mechanisms of these acetanilide herbicides. The abilities of herbicides to form these adsorption bonds with HA increased in the same order as the extent of adsorption.

Adsorption behavior of Sb(Ⅲ) in single and binary Sb(Ⅲ)-Fe(Ⅱ) systems on cationic ion exchange resin: Adsorption equilibrium, kinetic and thermodynamic aspects

The present study dealt with the mechanism of competitive adsorption of Sb(Ⅲ)and Fe(Ⅱ)ions from a copper-containing aqueous solution on Purolite S957,a commercially available cationic ion-exchange adsorbent.Experiments were conducted using aqueous copper sulfate solutions containing either single or conjoint ions,using both sedentary and batch adsorption techniques to ascertain the sensitivity of the adsorption process to variation in p H,mass of resin,contact time,and temperature as well as establishing the optimal range of variables for maximum ion removal.The data from single ion adsorption tests were fitted by non-linear regression techniques to Henry,Langmuir,Freundlich,Temkin,and Dubinin–Radushkevich isotherm models.Freundlich isotherm for Sb(Ⅲ)and Freundlich and Henry models for Fe(Ⅱ)solutions best express the adsorption equilibrium data;while for binary ion electrolytes,the extended Freundlich model fitted the data satisfactorily.The kinetic model adequately describing adsorption was shown to be the pseudo-first-order,underscoring the dominant role of physical adsorption playing in the process.Thermodynamic parameters for the adsorption process reveal differences in the Sb(Ⅲ)adsorption mechanism from single ion and Sb(Ⅲ)-Fe(Ⅱ)containing electrolytes.The adsorption of Sb(Ⅲ)alone is endothermic,whereas the process becomes exothermic in the Sb(Ⅲ)-Fe(Ⅱ)system.

Adsorption of dimethyl trisulfide from aqueous solution on a low-cost adsorbent:thermally activated pinecone

Thermally activated pinecone(TAP) was used for the adsorption of dimethyl trisulfide(DMTS)from aqueous solutions,which was proved to be the main odorous in algae-caused black bloom.The effects of adsorbent dosage,adsorbate concentration and contact time on DMTS biosorption were studied.The TAP produced at 600℃ exhibited a relatively high surface area(519.69 m^2/g) and excellent adsorption capacity.The results show that the adsorption of DMTS was initially fast and that the equilibrium time was6 h.Higher initial DMTS concentrations led to lower removal percentages but higher adsorption capacity.The removal percentage of DMTS increased and the adsorption capacity of TAP decreased with an increase in adsorbent dosage.The adsorption process conforms well to a pseudo-second-order kinetics model.The adsorption of DMTS is more appropriately described by the Freundlich isotherm(R^2=0.996 1) than by the Langmuir isotherm(R^2=0.916 9).The results demonstrate that TAP could be an attractive low-cost adsorbent for removing DMTS from water.

Design of Heat Pipe Type Adsorption Ice Maker for Fishing Boats

A heat pipe type adsorption ice maker with two adsorbers for fishing boats is designed by using ammonia as refrigerant and compound of activated carbon-CaCl2 as adsorbent. This type of heat pipe adsorber can solve the problem of incompatibility between ammonia, copper, seawater and steel. The working process of the ice maker with 8.7kg adsorbent per bed is simulated. The results show that the optimal semi-cycle time is about 9 min at the evaporating temperature of -15℃, where the corresponding cooling power, specific cooling power per kilogram adsorbent SCP and coefficient of refrigerant performance COP are respectively 3.6kW, 217W·kg-1 and 0.404.

Adsorption of catechol from aqueous solution by aminated hypercrosslinked polymers

Adsorption of catechol from aqueous solution with the hypercrosslinked polymeric adsorbent NDA-100 and its derivatives AH-1, AH-2 and AH-3 aminated by dimethylamine, the commercial resin Amberlite XAD-4 and weakly basic anion exchanger resin D301 was compared. It was found that the aminated hypercrosslinked resins had the highest adsorption capacities among the tested polymers. The empirical Freundlich equation was successfully employed to describe the adsorption process. Specific surface area and micropore structure of the adsorbent, in company with tertiary amino groups on matrix affected the adsorption performance towards catechol. In addition, thermodynamic study was carried out to interpret the adsorption mechanism. Kinetic study testified that the tertiary amino groups on the polymer matrix could decrease the adsorption rate and increase the adsorption apparent activation energy.

Conversion of Biomass to Hydrocarbon-rich Bio-oil via Microwave-assisted Catalytic Pyrolysis： A Review

The method for pyrolysis of biomass to manufacture hydrocarbon-rich fuel remains challenging in terms of conversion of multifunctional biomass with high oxygen content and low thermal stability into a high-quality compound, featuring high content of hydrocarbons, low oxygen content, few functional groups, and high thermal stability. This study offers a promising prospect to derive hydrocarbon-rich oil through microwave-assisted fast catalytic pyrolysis by improving the effective hydrogen to carbon ratio(H/Ceff) of the raw materials. The proposed technique can promote the production of high-quality bio-oil through the molecular sieve catalyzed reduction of oxygenated compounds and mutagenic polyaromatic hydrocarbons. This work aims to review and summarize the research progress on microwave copyrolysis and microwave catalytic copyrolysis to demonstrate their benefits on enhancement of bio-oils derived from the biomass. This review focuses on the potential of optimizing the H/Ceff ratio, the microwave absorbent, and the HZSM-5 catalyst during the microwave copyrolysis to produce the valuable liquid fuel. This paper also proposes future directions for the use of this technique to obtain high yields of bio-oils.

Effect of Adsorbent Diameter on the Performance of Adsorption Refrigeration

Adsorbents are important components in adsorption refrigeration. The diameter of an adsorbent can affect the heat and mass transfer of an adsorber. The effect of particle diameter on effective thermal conductivity was investigated. The heat transfer coefficient of the refrigerant and the void rate of the adsorbent layer can also affect the effective thermal conductivity of adsorbents. The performance of mass transfer in the adsorber is better when pressure drop decreases. Pressure drop decreases with increasing permeability. The permeability of the adsorbent layer can be improved with increasing adsorbent diameter. The effect of adsorbent diameter on refrigeration output power was experimentally studied. Output power initially increases and then decreases with increasing diameter under different cycle time conditions. Output power increases with decreasing cycle time under similar diameters.

ADSORPTION OF BENZOIC ACID AND P-NITROBENZOIC ACID ON A NEW HYPERCROSSLINKED PHENOL GROUP PST ADSORBENT

A comparison of the adsorption of benzoic acid and p-nitrobenzoic acid on the new hypercrosslinked polymeric adsorbent AM-1, with that by macroporous Amberlite XAD-4, including the equilibrium adsorption isotherms, the dynamic adsorption behaviors through column and the adsorption thermodynamics were studied. Results show that Freundlich equation gives a fitting adsorption isotherm. The specific surface of AM-1 is only 67% of that of Amberlite XAD-4, but the adsorption capacities on AM-1 are much higher about 125%~166% than that on Amberlite XAD-4, which is contributed to the micropore mechanism and polarity. The negative values of the adsorption enthalpy are indicative of an exothermic process. Enthalpy and free energy changes of adsorption both manifest a physic-sorption process. The negative values of the adsorption entropy indicate that the adsorption is well consistent with the restricted mobilities and the configurations of the adsorbed benzoic acid molecules on the surface of studied adsorbents with superficial heterogeneity. Both adsorbents were used in mini-column experiments for adsorbing benzoic acid expecting to elucidate the higher breakthrough adsorption capacity of the new hypercrosslinked polymeric adsorbent AM-1 as compared with that of Amberlite XAD-4.

KINETICS OF DEPOSITION OF METAL IONS TO ACTIVATED CARBON FIBERS (ACFs) WITH FLUIDIZATION

The diffusion and mass transfer, reaction, integration and growth processes of the metal ions on the activated carbon fibers (ACFs) are discussed. Based on the diffusion film theory, the diffusion and the integration model are developed to describe the deposition processes of metal ions from the solution to ACFs in the fluidized beds. The model of heat transfer of this process is established to expound the important role-played in deposition processes by the influence of the reaction heat released at ACFs surface and the non-uniform temperature distribution caused by hydrodynamics.

Influence of Low Temperature Dyeing Accelerant on Acrylic Fiber Dyed with Cationic Dyes

The dyeing behavior of cationic dyes to acrylic fiber with self-made low temperature dyeing accelerant was investigated in this study. Compared with conventional dyeing, the acrylic yarn was dyed with Cationic Turquoise Blue X-GB at 85℃ in the presence of accelerant and absence of accelerant, respectively. The influence of low temperature dyeing aceelerant on the dyeing mechanism of acrylic fiber dyed with cationic dye was analyzed through kinetics and thermodynamics study. The results show that adding dyeing accelerant ran heighten the equilibrium dye-uptake, dyeing rate constants, diffusion coefficients, and shorten half-dyeing time for acrylic fiber dyed with cationic dyes. Furthermore, the partition coefficient, the standard affinity, and the dye saturation value also increased in the dyeing at 85℃.

Synthesis of molybdenum disulfide/reduced graphene oxide composites for effective removal of Pb(Ⅱ) from aqueous solutions

In this work, a facile method was adopted to synthesize molybdenum disulfide/reduced graphene oxide （MoS2/rGO） composites through an c-cysteine-assisted hydrothermal technique, The as-prepared MoS2/ rGO composites were firstly applied as adsorbents for efficient elimination of Pb（Ⅱ） ions. Batch adsorption experiments showed that the adsorption of Pb（Ⅱ） on MoS2/rGO followed pseudo-second-order kinetic model well. The adsorption of Pb（Ⅱ） was intensely pH-dependent, ionic strength-dependent at pH 〈 9.0 and ionic strength-independent at pH 〉 9,0, The presence of humic acid （HA） enhanced Pb（Ⅱ） adsorption obviously. The MoS2/rGO composites exhibited excellent adsorption capacity of 384.16 mg g 1 at pH 5.0 and T = 298.15 K, which was superior to MOS2 （279.93 mg g 1） and many other adsorbents. The thermodynamic parameters suggested that the adsorption process of Pb（Ⅱ） on MoS2/rGO composites was spontaneous （zSG＂ 〈 O） and endothermic （△H 〉 0）. The interaction of Pb（Ⅱ） and MoS2] rGO was mainly dominated by electrostatic attraction and surface comple^ation between Pb（Ⅱ） and oxygen-containing functional groups of MoS2]rGO. This work highlighted the application of MoS21rGO as novel and promising materials in the efficient elimination of Pb（Ⅱ） from contaminated water and industrial effluents in environmental pollution management.

Ultrasensitive iron-based magnetic resonance contrast agent constructed with natural polyphenol tannic acid for tumor theranostics

Because of the toxicity of Gd(Ⅲ)complexes and the poor T1 magnetic resonance imaging(MRI)contrast of superparamagnetic iron oxide,the development of new stable,non-toxic,and efficient contrast agents is desirable.Herein,tannic acid(TA),a large natural polyphenol,and bovine serum albumin(BSA)were used to construct non-toxic Fe(Ⅲ)complexes with increased relaxivity based on a strategy slowing the molecular spin.Compared with the commercial T1 contrast agent Magnevist■,TA-Fe@BSA not only exhibits comparable T1 MRI contrast enhancement under 0.5,1 and 7 T magnetic fields both in vitro and in vivo,but also has better stability and biocompatibility.Moreover,TA-Fe@BSA with near-infrared(NIR)absorption demonstrates efficient tumor ablation via photothermal effects.These results demonstrate their strong potential as an alternative T1 MRI contrast agent and tumor theranostics agent in clinical settings.