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Continuous flow microwave sterilization for liquid food has advantages of a short time and high retention rate of nutrients. However, uneven microwave heating is the critical factor restricting the industrialization of microwave sterilization. This paper reviews the up-to-date research on the continuous flow microwave heating and the continuous flow microwave sterilization system for liquid food. The causes of the non-uniformity of continuous flow microwave heating are thoroughly discussed and the methods of improving the uniformity are proposed. Finally, the recommendations for future research of continuous flow microwave sterilization for liquid food are presented.

This paper systematically studied the changes of wort characteristic components under various low thermal stress boiling, and separation methods of Dimethyl-Sulfide (DMS) accumulated in wort due to low thermal stress boiling. Compared with conventional boiling, the combined boiling (boiling at 3% evaporation rate and 98 °C holding temperature for 30 min) demonstrated that the change rates of solidifiable nitrogen, iso-α-acid and color were no more than 5%, the absorbance of thiobarbituric acid (TBA) reaction mixture decreased by 13.7%, and DMS can be separated by vacuum film stripping after whirlpool. For 98 °C holding temperature boiling, the differences in absorbance of TBA reaction mixture, iso-α-acid and color were 16, 11.6 and 5%, respectively. The solidifiable nitrogen content was equivalent to the 28 mg/L limit and DMS must be removed by vacuum film stripping two times. From the perspective of application, it is necessary to improve the separation efficiency of DMS subsequently.

The skin effect causes about 86% of the energy to be concentrated in the narrow surface layer during the induction heating process, which leads to the uneven temperature distribution during the treatment of flowing liquid by induction heating technology. The concentration of heat caused by the skin effect can be avoided by dispersing the induced heating metal structure in the treated fluid, but in most cases, this will lead to a decrease in heating efficiency. Therefore, the purpose of this study is to compare and design the susceptor structures that can avoid the heating concentration problem caused by the skin effect and have higher efficiency. Hence, in this research four kinds of susceptor structures that are the metal sphere, sheet metal, static mixer, and metal pipe were studied. The results show that the combination of metal sphere susceptor and sheet metal susceptor can result in higher heating efficiency than the metal sphere susceptor alone. Ferromagnetic stainless steel with lower relative permeability is more suitable for making sheet metal susceptor than paramagnetic stainless steel. Adding internal components to the metal pipe susceptor will not change its heating efficiency. The heating efficiency of metal sphere type susceptor, sheet metal susceptor, and static mixer susceptor can be up to 58%, 64%, and 67%, respectively. When 430 metal pipe heater is used, the highest heating efficiency can be obtained, and the highest heating efficiency is 80%.

The rapid freezing of droplets on the surface of cold carrier particles can reduce the spray freeze-drying time. The coating freezing process can be treated in batch by using a spouted bed and the bed stability is the key. The freezing process of droplets would agglomerate the carrier particles. By analyzing the standard deviation of the bed pressure drop and the fluctuation of the bed pressure, the stable operating conditions of the spouted bed under cold coating were studied, and a dynamic adjustment method of the inlet air velocity to maintain stable spouting was proposed. The results show that the stable operating air velocity range can be described useing the standard deviation of pressure fluctuations. Before bed collapse occurs, it will experience an unstable spouting process, which causes the bed pressure to fluctuate a standard deviation of less than 15 Pa after more than 40 Pa.

A method of combining low-pressure superheated steam drying (LPSSD) and vacuum drying (VD) was proposed to improve the dried pineapple quality and increase the drying rate. It was found that the inversion temperature in low-pressure superheated steam drying of pineapple was 85.75 °C in terms of the first falling rate period. The combining drying (LPSSD–VD) reduced the maximum material temperature by 9.5 °C and 0.35 °C, and shortened the drying time by 50 min and 90 min compared with LPSSD and VD at the same drying temperature of 90 °C. The vitamin C retention rate of dried pineapple by LPSSD–VD was 29.33% and 15.94% higher than that of LPSSD and VD, respectively. The color of dried pineapple was also improved. Moreover, the sugar content of dried pineapple can be well controlled to meet the health demand of low sugar and ensure the taste of dried pineapple during LPSSD–VD process.

Low pressure superheated steam drying (LPSSD) is an attractive drying method, which can retain nutrients in fruits and vegetables well. To obtain high quality drying products, it is necessary to understand the main factors affecting the quality attribute of drying sample. Therefore, green turnip was selected as the drying sample and sensitivity analysis method was used to identify the main influencing factors of product quality, such as color, re-hydration performance and Vitamin C during LPSSD. The results showed that the drying temperature had the greatest influence on the color change and vitamin C retention of green turnip. The total color difference ΔE* increased with the elevated drying temperature. The drying pressure had the greatest influence on re-hydration performance and the re-hydration ratio decreased with the elevated drying pressure.

In this paper, we investigate the existence, number and stability of periodic orbits for the following contact Hamiltonian system $$H(p,q,s,t)=\frac{p^{2}}{2m}+G(t,q,m)-mdq+cs(c>0)$$ H ( p , q , s , t ) = p 2 2 m + G ( t , q , m ) - m d q + c s ( c > 0 ) . At the same time, unbounded conditions of each solution are also given. The contact Hamiltonian system actually represents a kind of physical phenomenon with non-conservation of energy, but the contact Hamiltonian system studied in this paper represents a one-dimensional damped oscillator system with constant variable sign damping coefficient under certain conditions. Therefore, it is of great physical significance to study the periodic dynamic properties of such system.

In microwave (MW) drying, the adjustable incident MW power is preferred to improve the product quality and reduce energy consumption. However, the control of incident MW power during the drying pro...

The mechanical molecular spring isolator (MMSI) presents the characteristics of high-static-low-dynamic-stiffness to isolate the low-frequency vibration of a heavy payload. An MMSI consists of a piston-cylinder container full of the liquid and some hydraulic spring accumulators. This paper focuses on a particular type of the MMSI that all hydraulic spring accumulators applying the conventional coil spring are identical. In the beginning, the MMSI stiffness model is modelled and the influences of critical parameters on the stiffness property are studied. The MMSI presents a piecewise linear stiffness property. The averaging method is applied to determine the primary resonance response, and the energy transmissibility is adopted to estimate the vibration isolation performance. A jump phenomenon is inevitable to be occurred around the resonance region. The jump avoidance is a critical design part of the MMSI isolation system. On the other hand, based on the stiffness model, it reveals that any stiffness of the coil spring or any size of the accumulator in the MMSI will be able to achieve the same desired stiffness property. The most significant difference between all solutions depends on the coil spring lateral stability. The coil spring lateral stability magnitude is defined as the ratio of the deflection to the buckling deflection to evaluate the quality of each solution. Then, the fundamental design criterion on the MMSI based on jump avoidance and the coil spring lateral stability is established.

In many engineering problems, when studying the existence of periodic solutions to a nonlinear system with a small parameter via the local averaging theorem, it is necessary to verify some properties of the fundamental solution matrix to the corresponding linearized system along the periodic solution of the unperturbed system. But sometimes, it is difficult or it requires a lot of calculations. In this paper, a few simple and effective methods are introduced to investigate the existence of periodic solutions for a kind of small parametric systems. In order to prove the existence of periodic solutions by these ideas, we also introduce a forced autoparametric vibrating system and a generalized model of the tuned mass absorber with pendulum discussed by Brzeski, Perlikowski, and Kapitaniak. Then, we also propose an averaging method to study the existence of periodic solutions.

Machine learning techniques have attracted more attention as advanced data analytics in building energy analysis. However, most of previous studies are only focused on the prediction capability of machine learning algorithms to provide reliable energy estimation in buildings. Machine learning also has great potentials to identify energy patterns for urban buildings except for model prediction. Therefore, this paper explores energy characteristic of London domestic properties using ten machine learning algorithms from three aspects: tuning process of learning model; variable importance; spatial analysis of model discrepancy. The results indicate that the combination of these three aspects can provide insights on energy patterns for urban buildings. The tuning process of these models indicates that gas use models should have more terms in comparison with electricity in London and the interaction terms should be considered in both gas and electricity models. The rankings of important variables are very different for gas and electricity prediction in London residential buildings, which suggests that gas and electricity use are affected by different physical and social factors. Moreover, the importance levels for these key variables are markedly different for gas and electricity consumption. There are much more important variables for electricity use in comparison with gas use for the importance levels over 40. The areas with larger model discrepancies can be determined using the local spatial analysis based on these machine learning models. These identified areas have significantly different energy patterns for gas and electricity use. More research is required to understand these unusual patterns of energy use in these areas.

Waste cooking oil was used to dry sewage sludge by fry-drying technology. The obtained oil-fried sludge, which contained waste cooking oil and sewage sludge, was converted into biofuel simultaneously via pyrolysis process in a fixed bed. The synergistic effects of sewage sludge and waste cooking oil on the pyrolysis products were also investigated. Comparing to pyrolysis of sludge, pyrolysis of oil-fried sludge can obtain 51.9% higher gas products, where H2 and CH4 yields were increased by 37.4% (up to 211 ml/g) and 163% (up to 155 ml/g), respectively. The lower heating value (LHV) of gas product from oil-fried sludge was 41.2% higher than that from sludge. The higher LHV of gaseous products can be beneficial to use for power generation and heating. This indicates that oil-fried sludge shows a potential feedstock can be converted into high valuable biofuel. Nevertheless, the experimental gas and tar yield values of oil-fried sludge were lower than calculated values, indicating that there is an anergy effect of interactions between SS and oil on gas and tar formations. This was because the oily materials layer inhibited the heat and mass transfer in the sludge pyrolysis process, and then hindering the conversion of sludge into gas and tar formation.

How molecules approach, bind at, and release from catalytic sites is key to heterogeneous catalysis, including for emerging metal-organic framework (MOF)-based catalysts. We use in situ synchrotron X-ray scattering analysis to evaluate the dominant binding sites for reagent and product molecules in the vicinity of catalytic Ni-oxo clusters in NU-1000 with different surface functionalization under conditions approaching those used in catalysis. The locations of the reagent and product molecules within the pores can be linked to the activity for ethylene hydrogenation. For the most active catalyst, ethylene reagent molecules bind close to the catalytic clusters, but only at temperatures approaching experimentally observed onset of catalysis. The ethane product molecules favor a different binding location suggesting that the product is readily released from the active site. An unusual guest-dependence of the framework negative thermal expansion is documented. We hypothesize that reagent and product binding sites reflect the pathway through the MOF to the active site and can be used to identify key factors that impact the catalytic activity.

Spray-freeze drying (SFD) is a novel and advanced drying technology in the production of high-value foods and pharmaceuticals. However, long drying time is still a disadvantage for the SFD applicat...

The understanding of the catalyst-support interactions has been an important challenge in heterogeneous catalysis since the supports can play a vital role in controlling the properties of the active species and hence their catalytic performance. Herein, a series of isostructural mesoporous metal-organic frameworks (MOFs) based on transition metals, lanthanides, and actinides (Zr, Hf, Ce, Th) were investigated as supports for a vanadium catalyst. The vanadium species was coordinated to the oxo groups of the MOF node in a single-ion fashion, as determined by single-crystal X-ray diffraction, diffuse reflectance infrared Fourier transform spectroscopy, and diffuse reflectance UV-vis spectroscopy. The support effects of these isostructural MOFs were then probed using the aerobic oxidation of 4-methoxybenzyl alcohol as a model reaction. The turnover frequency was found to be correlated with the electronegativity and oxidation state of the metal cations on the supporting MOF nodes, highlighting an important consideration when designing catalyst supports.

Previous work has shown that introduction of hexafluoroacetylacetone (Facac) units as nonstructural ligands for the zirconia-like nodes of the eight-connected metal–organic framework (MOF), NU-1000, greatly alters the selectivity of node-supported oxy-nickel clusters for ethylene dimerization vs oligomerization. Here we explore a related concept: tuning of support/catalyst interactions, and therefore, catalyst activity, via parallel installation of organic modifiers on the support itself. As modifiers we focused on para-substituted benzoates (R-BA–; R = −NH2, −OCH3, −CH3, −H, −F, and −NO2) where the substituents were chosen to present similar steric demand, but varying electron-donating or electron-withdrawing properties. R-benzoate-engendered shifts in the node-based aqua O–H stretching frequency for NU-1000, as measured by DRIFTS (diffuse-reflectance infrared Fourier-transform spectroscopy), together with systematic shifts in Ni 2p peak energies, as measured by X-ray photoelectron spectroscopy, show tha...

Ultrasound is a promising method to enhance heat transfer in industrial evaporators. However, there are very limited studies on this topic. This paper explores thermal performance of a novel ultrasonic evaporator based on machine learning methods. The results indicate that the overall heat transfer coefficients can be increased by around 15–20% after adding ultrasound due to acoustic cavitation and acoustic streaming. Two machine learning-based global sensitivity analysis (treed Gaussian Process and polynomial chaos expansion) methods are used to identify important variables influencing overall heat transfer coefficients in the ultrasonic evaporator. It is found that the temperature difference between evaporation and heating steam is the dominant factor affecting thermal performance in this case study. Ultrasound has complicated interactions and non-linear effects in the ultrasonic evaporator. Seven machine learning algorithms are created to compare predictive thermal performance of this evaporator, including linear model, Lasso (least absolute shrinkage and selection operator), MARS (multivariate adaptive regression splines), NNet (averaging neural network), CB (Cubist model), GP (Gaussian process), and SVM (support vector machine). The SVM and NNet models among these seven models can provide accurate prediction of overall heat transfer coefficients in the ultrasonic evaporator.

Spray freeze-drying is a process to directly produce high quality powders with short drying time. The difference of microstructures has a great influence on the physical properties of powders. However, during the spray freeze-drying process, the freezing degree of droplets in the drying chamber will change the product structure and affect the powder quality. In this study, the surface structure and morphology of dry powders were observed using scanning electron microscopy. The formation mechanism of droplet morphology during spray freeze-drying was analyzed. The results show that the rapid freezing process can produce finer microstructures.

Activated carbon (AC) was modified by using non-thermal plasma in O2, N2 and O2/N2 atmospheres to increase its Cu(II) adsorption capacity and quantify the influences of the modifying atmospheres. SEM, BET, FT-IR and XPS were used to characterize the surface physical and chemical properties of AC. The results show that the AC modified by using plasma had significantly better Cu(II) adsorption performance than the raw AC. Among the O2, N2 and O2/N2 atmospheres, the AC with plasma modification in N2 showed best Cu(II) adsorption performance and the Cu(II) adsorption capacity was 369.5% higher than the raw AC. The AC modified in O2 atmosphere can form C—COOH groups, while the AC modified in N2 atmosphere can form C—NH2 groups. These two groups are both beneficial for Cu(II) adsorption, where the —NH2 groups are more effective for Cu(II) adsorption compared to —COOH groups. The chemisorption dominated the Cu(II) adsorption on the plasma modified AC and the adsorption performance was dependent on the surface functional groups properties of AC.

Topology and porosity control of Zr6-based MOFs was achieved by introducing steric functionalization into the conformations of substituted tetracarboxylate linkers., Tetratopic organic linkers have been extensively used in Zr-based metal–organic frameworks (MOFs) where diverse topologies have been observed. Achieving meticulous control over the topologies to tune the pore sizes and shapes of the resulting materials, however, remains a great challenge. Herein, by introducing substituents to the backbone of tetratopic linkers to affect the linker conformation, phase-pure Zr-MOFs with different topologies and porosity were successfully obtained under the same synthetic conditions. The conversion of CO2 to valuable cyclic carbonates is a promising route for the mitigation of the greenhouse gas. Owing to the presence of substrate accessible Lewis acidic Zr(iv) sites in the 8-connected Zr6 nodes, the Zr-MOFs in this study have been investigated as heterogenous acid catalysts for CO2 cycloaddition to styrene oxide. The MOFs exhibited drastically different catalytic activities depending on their distinct pore structures. Compared to previously reported MOF materials, a superior catalytic activity was observed with the mesoporous NU-1008, giving an almost 100% conversion under mild conditions.

Uncertainty and sensitivity analysis of building energy has become an active research area in order to consider variations of input variables and identify key variables influencing building energy. When there is only limited information available for uncertainty of building inputs, a specific probability for a given variable cannot be defined. Then, it is necessary to develop alternative approaches to probabilistic uncertainty and sensitivity analysis for building energy. Therefore, this paper explores the application of the Dempster-Shafer theory (DST) of evidence to conduct uncertainty and sensitivity analysis for buildings. The DST method is one of imprecise probability theories to allow combining uncertainty from different sources in terms of interval-valued probabilities in order to construct the belief and plausibility (two uncertainty measures) of system responses. The results indicate that the DST uncertainty analysis in combination with machine learning methods can provide fast and reliable information on uncertainty of building energy. It is recommended that at least two inherently different learning algorithms should be applied to provide robust simulation results of building energy. A spectrum of distributions should be implemented in global sensitivity analysis with the DST method because there are no specific distributions for intervals of input factors. Moreover, the stability of results from uncertainty and sensitivity analysis should be assessed when applying the DST method in building energy analysis.

We describe herein the highly selective semihydrogenation of acetylene to ethylene using a Zr-based metal–organic framework (MOF; NU-1000) with Cu–oxo clusters present on the nodes as precatalysts. The active form of the catalyst is MOF-supported Cu nanoparticles generated in situ upon a brief H2 reduction treatment at 200 °C. This composite material is stable for many catalytic cycles and effectively avoids overreduction to ethane, a common problem for many semihydrogenation catalysts.

The Zr6-based metal–organic framework NU-1000 was successfully functionalized with candidate catalysts—MoSx units—via SIM (solvothermal deposition in MOFs) of molybdenum(VI), followed by reaction with H2S gas. The structure of the material, named MoSx-SIM, was characterized spectroscopically and through a single-crystal X-ray diffraction measurement. These measurements and others established that the catalyst is monometallic, with mixed oxygen and sulfur coordination, and that it forms from a MOF-node-supported molybdenum-based cluster featuring only oxy ligands. Notably, the formal potential for the MOF-grafted complex, like that for the metal–sulfur active site of hydrogenase, is nearly coincident with the formal potential for the hydrogen couple. Its effective concentration within the mesoporous MOF is several hundred millimolar, and its porous-framework-based immobilization/heterogenization obviates the need for aqueous solubility as a condition for use as a well-defined catalyst. MoSx-SIM was evaluat...

To modify its steric and electronic properties as a support for heterogeneous catalysts, electron-withdrawing and electron-donating ligands, hexafluoroacetylacetonate (Facac–) and acetylacetonate (Acac–), were introduced to the metal–organic framework (MOF), NU-1000, via a process akin to atomic layer deposition (ALD). In the absence of Facac– or Acac–, NU-1000-supported, AIM-installed Ni(II) sites yield a mixture of C4, C6, C8, and polymeric products in ethylene oligomerization. (AIM = ALD-like deposition in MOFs). In contrast, both Ni-Facac-AIM-NU-1000 and Ni-Acac-AIM-NU-1000 exhibit quantitative catalytic selectivity for C4 species. Experimental findings are supported by density functional theory calculations, which show increases in the activation barrier for the C–C coupling step, due mainly to rearrangement of the siting of Facac– or Acac– to partially ligate added nickel. The results illustrate the important role of structure-tuning support modifiers in controlling the activity of MOF-sited heterog...

The prospect of using copper oxide nanoclusters grown by atomic layer deposition on a porphyrin support for selective oxidation of methane to methanol was examined by means of density functional theory (DFT) calculations. Ab initio thermodynamic analysis indicates that an active site in the form of Cu(μ-O)Cu can be stabilized by activation in O2 at 465 K. Furthermore, a moderate methane activation energy barrier (Ea = 54 kJ/mol) is predicted, and the hydrogen abstraction activity of the active site could be attributed to the radical character of the bridging oxygen. Methanol extraction in this system is limited by a thermodynamic barrier to desorption of ΔG = 57 kJ/mol at 473 K; however, desorption can be facilitated by the addition of water in a “stepped conversion” process. Overall, our results indicate similar activity between porphyrin-supported copper oxide nanoclusters and existing Cu-exchanged zeolites and provide a computational proof-of-concept for utilizing functionalized organic linkers in metal-organic frameworks (MOFs) for selective oxidation of methane to methanol.

Organocatalytic polymerization reactions have a number of advantages over their metal-catalyzed counterparts, including environmental friendliness, ease of catalyst synthesis and storage, and alternative reaction pathways. Here we introduce an organocatalytic polymerization method called benzylic chloromethyl-coupling polymerization (BCCP). BCCP is catalyzed by organocatalysts not previously employed in polymerization processes (sulfenate anions), which are generated from bench-stable sulfoxide precatalysts. The sulfenate anion promotes an umpolung polycondensation via step-growth propagation cycles involving sulfoxide intermediates. BCCP represents an example of an organocatalyst that links monomers by C=C double bond formation and offers transition metal-free access to a wide variety of polymers that cannot be synthesized by traditional precursor routes., Polymerization reactions are often catalysed by metal compounds and hence there are concerns surrounding toxicity, cost and environmental friendliness. Here the authors show sulfenate anions as organocatalysts for benzylic chloromethyl-coupling polymerization reactions to form poly(stilbene)s.

The dielectric barrier discharge (DBD) non-thermal plasma was used to modify the phosphoric acid activated carbon (AC) for enhancing its adsorption performance of Cu(II). The BET, SEM-EDX, FT-IR, elemental analysis and XPS techniques were employed to determine the textural structure and surface chemistry of the raw and plasma modified ACs. The results indicate that the ACs after using plasma modification have much higher Cu(II) adsorption capacity, irrespective of different adsorption conditions, such as solution pH, temperature, dosage and agitation speed. Importantly, the adsorption capacity of Cu(II) on AC has a non-monotonic variation (increasing at first and then decreasing) with the plasma modification time. The optimum modification time was 7.5 min in this study and the Cu(II) adsorption capacity of the modified AC could be improved by about 150% compared to that of the raw AC. Interestingly, the Cu(II) adsorption capacity showed good exponential relationship with the content of carboxylic groups, while it showed significant linear relation with the quantity of phosphates and pyrophosphates groups, indicating that these functional groups play key roles on Cu(II) adsorption. Furthermore, plasma modification improved Cu(II) removal regeneration performance of AC.

Nanocasting can be a useful strategy to transfer the catalytic metal clusters in metal-organic frameworks (MOFs) to an all-inorganic support such as silica. The incorporation of silica in the MOF pores as a secondary support has the potential to extend the application of the highly tunable metal-based active sites in MOFs to high temperature catalysis. Here, we demonstrate the applicability of the nanocasting method to a range of MOFs that incorporate catalytically attractive hexazirconium, hexacerium, or pentanickel oxide-based clusters (UiO-66, (Ce)UiO-66, (Ce)UiO-67, (Ce)MOF-808, DUT-9, and In- and Ni-postmetalated NU-1000). We describe, in tutorial form, the challenges associated with nanocasting of MOFs that are related to their small pore size and to considerations of chemical and mechanical stability, and we provide approaches to overcome some of these challenges. Some of these nanocast materials feature the site-isolated clusters in a porous, thermally stable silica matrix, suitable for catalysis at high temperatures; in others, structural rearrangement of clusters or partial cluster aggregation occurs, but extensive aggregation can be mitigated by the silica skeleton introduced during nanocasting.

Two kinds of pinewood sawdust activated carbon adsorbents were prepared by fast activation with H3PO4 in a spouted bed, and the application in adsorption of copper ions was investigated. With only 3 min of activation time, the BET surface area of activated carbons reached 1537.5 m2/g for impregnation mass ratio of H3PO4 to sawdust at 1:1 and activation temperature of 500 °C (IR1-500), whereas it was 1750.7 m2/g for the impregnation ratio at 4:1 and activation temperature of 800 °C (IR4-800). The pseudo second-order reaction kinetics well describes the experimental adsorption of copper ion in this study, indicating chemisorption dominated in the process. By the C1s spectrum, activated carbons from IR1-500 contained more carboxyl groups (-COOH) and carbonyl groups (C=O), which played an important role in copper ions adsorption. In addition, it was found that the P-containing groups (metaphosphates) also involved in the adsorption of copper ion.

Single atoms and few-atom clusters of platinum are uniformly installed on the zirconia nodes of a metal-organic framework (MOF) NU-1000 via targeted vapor-phase synthesis. The catalytic Pt clusters, site-isolated by organic linkers, are shown to exhibit high catalytic activity for ethylene hydrogenation while exhibiting resistance to sintering up to 200 °C. In situ IR spectroscopy reveals the presence of both single atoms and few-atom clusters that depend upon synthesis conditions. Operando X-ray absorption spectroscopy and X-ray pair distribution analyses reveal unique changes in chemical bonding environment and cluster size stability while on stream. Density functional theory calculations elucidate a favorable reaction pathway for ethylene hydrogenation with the novel catalyst. These results provide evidence that atomic layer deposition (ALD) in MOFs is a versatile approach to the rational synthesis of size-selected clusters, including noble metals, on a high surface area support.

X-ray computed tomography (CT) is one of the most useful imaging technologies in the clinic. To increase the sensitivity of CT, iodinated compounds are used as injectable contrast agents. Unfortunately, the rapid renal clearance results in a narrow imaging window for diagnosis. In addition, the non-specific distributions and high osmolality of small molecules may induce serious adverse effects. However, nanoparticles can substantially overcome these limitations. As a result, developing new iodinated nanoparticles with high feasibility and availability as contrast agents is highly demanded for CT diagnosis. Herein, we reported fundamental research with a one-pot strategy for the synthesis of iohexol nanoparticles (INPs) on a large scale via polymerization-induced self-assembly (PISA) for CT imaging. The crosslinked core of INPs can increase the loading efficiency of iohexol to 36.5%, yielding sufficient contrast in CT imaging. Moreover, the stability of INPs was enhanced significantly via the core-crosslinking, allowing a good dispersion even in an extremely high concentration (120 mg mL−1). Compared to iohexol, the INPs showed a longer circulation time, negligible toxicity, analogous imaging capability and prominent accumulation in tumors. With these advantages, INPs could become better alternative contrast agents for cancer diagnosis and angiography in vivo.

Non-thermal plasma in ultrafine water mist (UWM) is proposed to increase the content of COOH groups on the surface of raw walnut shell in order to improve its performance in the removal of Cu(II) from wastewater. The modified walnut shell surface was characterized by various techniques (BET, SEM-EDX and XPS), and it was observed that more COOH groups were generated. Oxygen disassociated from water mist by plasma bonded with the walnut shell to form activated sites of COOH groups. After Cu(II) adsorption, the COOH group content in the walnut shell decreased because some groups were changed into C–O groups by Cu(II) chemisorption with COOH groups. The Cu(II) removal efficiency was 33.5% for raw walnut shell; however, the efficiency increased to 98% after plasma modification for 15 min under 3 g min−1 water mist. The maximum Cu(II) adsorption capacity of the UWM-plasma-modified WNS was 39.4 mg g−1 at pH 5.3 and 25 °C, around 8 times that of the raw WNS. This implies that UWM-plasma modification is a potential method for improving the Cu(II) adsorption performance of raw biomass.

Activated carbons were produced from waste pine wood sawdust using fast activation with H3PO4 in a spouted bed. In this study, activation temperature was set as 800 °C, and activation time ranged from 1 to 15 min. Experimental results show that sawdust impregnated with higher mass ratio of H3PO4 would be agglomerated in spouted bed, and difficult to fluidize. Therefore, an amount of quartz sand was added to assist for good fluidization. Fluidization of particle can improve the BET surface area or micropore volume of activated carbons. High BET surface area activated carbons can be obtained with activation time of only 1–5 min by combining the fluidization and H3PO4 fast activation. The obtained activated carbons contained developed pore structure and abundant surface functional groups (carboxyl, carbonyl and P-containing groups) by SEM–EDS, FTIR and XPS techniques. The particles of impregnation ratio of 1:1 can achieve fluidization without adding the quartz sand, which was convenient for experimental operation and even industrial production, and the BET surface area can reach more than 1000 m2/g in activation time of only 5 min.

Metal–organic frameworks (MOFs), with their well-ordered pore networks and tunable surface chemistries, offer a versatile platform for preparing well-defined nanostructures wherein functionality such as catalysis can be incorporated. Notably, atomic layer deposition (ALD) in MOFs has recently emerged as a versatile approach to functionalize MOF surfaces with a wide variety of catalytic metal-oxo species. Understanding the structure of newly deposited species and how they are tethered within the MOF is critical to understanding how these components couple to govern the active material properties. By combining local and long-range structure probes, including X-ray absorption spectroscopy, pair distribution function analysis, and difference envelope density analysis, with electron microscopy imaging and computational modeling, we resolve the precise atomic structure of metal-oxo species deposited in the MOF NU-1000 through ALD. These analyses demonstrate that deposition of NiOxHy clusters occurs selectively ...

Copper oxide clusters synthesized via atomic layer deposition on the nodes of the metal–organic framework (MOF) NU-1000 are active for oxidation of methane to methanol under mild reaction conditions. Analysis of chemical reactivity, in situ X-ray absorption spectroscopy, and density functional theory calculations are used to determine structure/activity relations in the Cu-NU-1000 catalytic system. The Cu-loaded MOF contained Cu-oxo clusters of a few Cu atoms. The Cu was present under ambient conditions as a mixture of ∼15% Cu+ and ∼85% Cu2+. The oxidation of methane on Cu-NU-1000 was accompanied by the reduction of 9% of the Cu in the catalyst from Cu2+ to Cu+. The products, methanol, dimethyl ether, and CO2, were desorbed with the passage of 10% water/He at 135 °C, giving a carbon selectivity for methane to methanol of 45–60%. Cu oxo clusters stabilized in NU-1000 provide an active, first generation MOF-based, selective methane oxidation catalyst.

Understanding the important role of the surface roughness of nano/colloidal particles and harnessing them for practical applications need novel strategies to control the particles' surface topology. Although there are many examples of spherical particles with a specific surface roughness, nonspherical ones with similar surface features are rare. The current work reports a one-step, straightforward, and bioinspired surface engineering strategy to prepare ellipsoidal particles with a controlled surface roughness. By manipulating the unique chemistry inherent to the oxidation-induced self-polymerization of dopamine into polydopamine (PDA), PDA coating of polymeric ellipsoids leads to a library of hybrid ellipsoidal particles (PS@PDA) with a surface that decorates with nanoscale PDA protrusions of various densities and sizes. Together with the advantages originated from the anisotropy of ellipsoids and rich chemistry of PDA, such a surface feature endows these particles with some unique properties. Evaporative drying of fluorinated PS@PDA particles produces a homogeneous coating with superhydrophobicity that arises from the two-scale hierarchal structure of microscale interparticle packing and nanoscale roughness of the constituent ellipsoids. Instead of water repelling that occurs for most of the lotus leaf-like superhydrophobic surfaces, such coating exhibits strong water adhesion that is observed with certain species of rose pedals. In addition, the as-prepared hybrid ellipsoids are very efficient in preparing liquid marble-isolated droplets covered with solid particles. Such liquid marbles can be placed onto many surfaces and might be useful for the controllable transport and manipulation of small volumes of liquids.