Recent advances in nanostructured Sn−Ln mixed-metal oxides as sunlight-activated nanophotocatalyst for high-efficient removal of environmental pollutants

Environmental contaminants are toxic and undesirable compounds that can endanger the health and survivorship of human society. Thus, their removal from the environment has become a hot subject of research. Photocatalysis is accepted as a beneficial and environmentally friendly solution for the removal of undesirable contaminants. Its most substantial advantage is the capability to mineralize a wide variety of contaminants. Among various nanoscale compounds, mixed-metal oxides of tin (Sn) and lanthanide (Ln) with unique features and high reactivity have been demonstrated to be promising photocatalysts for removing undesirable contaminants. This review is aimed to give a comprehensive overview of current research progress concerning solar photocatalytic applications utilizing mixed-metal oxides of tin (Sn) and lanthanide (Ln). Diverse techniques for fabrication of mixed-metal oxides of tin (Sn) and lanthanide (Ln) and comprehensive experimental outcomes revealing their application in solar photocatalysis for removing undesirable pollutants are summarized. Besides, factors influencing the solar photocatalytic process have been briefly discussed. Ultimately, inspiring outlooks on this area of research are offered with the purpose of prevailing challenges.     

Occurrence,Treatment, and Toxicological Relevance of EDCs and Pharmaceuticals in Water

Over the past decade a great amount of interest has arisen regarding the occurrence and fate of trace organic contaminants in the aquatic environment. Of particular concern are human hormones and pharmaceuticals, many of which are ubiquitous contaminants in conventional municipal wastewater treatment plant effluents when measured with ng/L detection limits. As analytical procedures and bioassay techniques become more readily available and increasingly sensitive, new contaminants will be discovered. The presence or absence of any chemical in a wastewater effluent is essentially a function of analytical detection capability. This poses a unique challenge for drinking water treatment plants intent on the removal of organic contaminants, as complete removal is merely a reflection of reporting limits. The investigation described here sought to determine the occurrence, treatment, and human health relevance of a chemically diverse group of emerging contaminants.     

The analysis of cationic surfactants

Long-chain cationic surfactants have become a very important class of industrial chemicals. These useful oleochemicals are usually based on vegetable oils and animal fats. They have many applications which include fabric softeners, antistatic agents, organo clays, emulsifiers, germicides, flotation, chemicals, corrosion inhibitors and foam depresents. The fatty quaternary ammonium compounds (quats) are by far the most important of this group of the commerical compounds. However, the fatty amine salts and amine oxides must also be classified as cationic surfactants. Although not as widely used as quats, they have special properties and uses which are often unique and useful. The various analytical methods used for these chemicals serves several objectives, including routine quality control, identification and characterization, determination in mixtures and formulations, determination at use level, and determination in the environment. In general, the objective of the analysis will determine what method will be used. Routine quality control procedures will most often use wet methods or some simple instrumental techniques. Identification and characterization of unknown cationic samples often require the most sophisticated of instrumental and chromatographic methods. Use level and environmental samples usually must be analyzed using the most sensitive methods. Often, colorimetric analysis is adequate. These samples often must undergo rigorous separation and celan-up techniques before the method of choice can be used. The methodology for the analysis of fatty amines, amine oxides and quaternary ammonium compounds is reviewed with the various analytical objectives in mind. However, the main emphasis is placed on the quats.     

土壤和地下水环境中胶体与污染物共迁移研究进展

天然胶体在土壤和地下水环境中广泛存在。由于胶体不仅具有粒径小、比表面积大、表面带有电荷等基本特点,而且具有独特的双电层结构和丰富的表面官能团,这些特点使得胶体成为地下环境中最为活跃的组分,并对土壤与地下水中污染物的迁移产生重要影响。近年来,土壤与地下水环境中的胶体及其对污染物的促进迁移作用受到越来越多研究者的关注。综述了地下环境中的胶体来源、可移动胶体的释放与沉积、胶体自身的特征与环境行为以及胶体对不同污染物的促进迁移作用,分析了各种环境因子对胶体-污染物共迁移的影响。在此基础上,对地下环境中胶体与污染物共迁移的过程与机理等尚需深入研究的关键科学问题提出了研究展望。     

High throughput kinetic analysis of photopolymer conversion using composition and exposure time gradients

In this work, monomer composition and exposure time gradients were produced, allowing for rapid, parallel measurements of conversion as a function of composition and exposure time using Fourier transform infrared (FT-IR) spectroscopy. A more comprehensive understanding of how composition affects photopolymerization kinetics is needed due to the complexity of current industrial formulations. In nearly all cases, these applications use multiple monomers, fillers, initiators, and other components to achieve the required properties. The developed technique allows for photopolymerization kinetics to be analyzed rapidly over a large range of compositions, giving a unique insight into the role composition contributes to polymerization kinetics and ultimate conversion within complex formulations. This work analyzed three varied two-component systems, each showing different effects from composition on polymerization kinetics due to formulation changes in functionality, viscosity, and reactivity.     

The photooxidation and stabilisation of water-borne acrylic emulsions

The influence of light exposure on the photooxidative stability of aqueous acrylic based latices is examined by Fourier transform-infrared spectroscopy (FT-IR) and hydroperoxide analysis. These are based on emulsion polymerised formulations of methyl methacrylate and butyl acrylate. Here acrylic latices based on different formulations are chosen as homo-polymers and copolymers. The nature of impurities and oxidation products generated during their manufacture are characterised and inter-related to their influence on subsequent photooxidative degradation. This involves the use of reflectance FT-IR spectroscopy to show functional group changes together with colorimetric UV analysis to determine photochemical generation of hydroperoxides. The early chemical changes and their subsequent influence on the physical and chemical properties of the latices during the later stages of photooxidation are found to exhibit a close inter-relationship. In terms of stabilisation co-reactive hindered piperidine stabilisers are found to be effective and nono-extractable. However, the incorporation of simple terminal dialkyl acrylamide/methacrylamide groups are equally as effective.     

Fourier transform infrared spectroscopy in surfactant science: A personal view

The overall goal of this review paper on Fourier transform infrared spectroscopy (FT-IR) is to provide non-specialists and spectroscopists alike a motivational introduction to how this technique may be used to obtain unique structural information on a wide range of surfactant-based systems. Two main topics are addressed—The structures of surfactant aggregates in solution and the interactions of surfactants in solution with solid surfaces. Infrared spectra can yield insights into the interactions of surfactants in mixed micelles as well as in microemulsions. The structures of adsorbed surfactant layers and their kinetics of formation may be elucidated from FT-IR spectra obtained using attenuated total reflectance sampling techniques. Insights into the detergency process of solid oily soils may also be obtained from the spectra of phases formed at the soil-surfactant solution interface. Future work in applying FT-IR to the development of the hydrophilic–lipophilic difference + net average curvature (HLD-NAC) framework is proposed. Spectral interpretation principles examined in many examples, particularly regarding surfactant hydration and the loci of oil solubilization, could be used in the further development of HLD-NAC through application to some microemulsion systems that have recently been reported.     

Optimization of multicomponent photopolymer formulations using high‐throughput analysis and kinetic modeling

While high throughput and combinatorial techniques have played an instrumental role in materials development and implementation, numerous problems in materials science and engineering are too complex and necessitate a prohibitive number of experiments, even when considering high throughput and combinatorial approaches, for a comprehensive approach to materials design. Here, we propose a unique combination of high throughput experiments focused on binary formulations that, in combination with advanced modeling, has the potential to facilitate true materials design and optimization in ternary and more complex systems for which experiments are never required. Extensive research on the development of photopolymerizable monomer formulations has produced a vast array of potential monomer/comonomer, initiator and additive combinations. This array dramatically expands the range of material properties that are achievable; however, the vast number of potential formulations has eliminated any possibility of comprehensive materials design or optimization. This limitation is addressed by maximizing the benefits and unique capabilities of high throughput experimentation coupled with predictive models for material behavior and properties. The high throughput experimentation‐model combination is useful to collect a limited amount of data from as few as 11 experiments on binary combinations of 10 analyzed monomers, and then use this limited data set to predict and optimize formulation properties in ternary resins that would have necessitated at least 1000 high throughput experiments and several orders of magnitude greater numbers of traditional experiments. A data analysis approach is demonstrated, and the model development and implementation for one model application in which a range of material properties are prescribed, and an optimal formulation that meets those properties is predicted and evaluated. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

Adhesion and Surface Analysis

In the last 25 years, surface sensitive analytical techniques have made a major contribution to our understanding of adhesion phenomena and problems. There are several areas where these techniques have provided important information including the identification of failure modes, the chemistry of a substrate before and after pretreatments, the stability of surfaces and interfaces, the identification of surface contaminants, the interaction across an interface and the nature of interphases. X-ray photoelectron spectroscopy (XPS or ESCA), Auger electron spectroscopy (AES) and static secondary ion mass spectrometry (SSIMS) have proved to be especially useful. Many examples of the usefulness of these techniques are given.     

Some applications of FT-IR spectrometry for the analysis of coatings and surfaces in packaged food substances

Infrared spectrometry is demonstrated to be a powerful tool for solving problems related to the use of polymeric materials in food packaging. These problems range from the identification of minute amounts of materials, such as flavor agents retained in coatings, to the investigation of adhesion problems in laminate wraps and to the identification of gross amounts of deposit discovered in a lemonade can. In some instances, a complex mixture of organic vapors is separated using standard chromatographie techniques, with subsequent analysis by FT-IR spectroscopy. In particular, the utility of headspace GC/ FT-IR analysis is discussed, as this technique is not routinely used. In other cases, the solid samples themselves are examined by more conventional FT-IR methodologies.     

Energy optimization in heat integrated water allocation networks

In this paper, linear programming formulations, complemented by concept based pinch analysis results, are developed to target the minimum energy requirements in a heat integrated fixed flow rate water allocation networks. These formulations can be applied for the cases of heat integration through isothermal and non-isothermal mixing in water allocation networks involving single as well as multiple contaminants. The earlier reported approaches are based on linear programming formulation for the case of isothermal mixing and either mixed integer non-linear programming or discontinuous non-linear programming formulations for the case of non-isothermal mixing. It has been observed that the earlier reported methodologies produce sub-optimal results for the case of non-isothermal mixing. However, the proposed methodologies produce the optimum results because of the rigorously proved linear formulation. Utility requirements for isothermal as well as for non-isothermal mixing cases are compared over a range of minimum approach temperatures, to evaluate the energy performance using illustrative examples.     

Temperature Profiling of Glass by FT-IR Emission Spectroscopy

Fourier transform infrared (FT-IR) spectroscopy is utilized to measure the wavelength and temperature-dependent radiative properties of two glass formulations. The information gained is then used with FT-IR measurements of radiance from hot glass to determine temperature gradient profiles through each glass thickness. Temperature profiling of clear Corning Pyrex and green-tinted PPG Solex are presented. The Solex was measured on-line, in situ during production at the industrial kiln. Since a temperature profile (not just bulk average) is obtained, the method offers a better understanding of process conditions for the glass industry.     

Critique of dielectric cure monitoring in epoxy resins – Does the method work for commercial formulations?

Dielectric techniques can be used as an in situ monitor of resin cure. This study reports measurements on two commercial resin formulations and aims to establish the extent to which identifiable turning points in the dielectric behaviour are dependent of the formulation used. Complementary curometer and differential scanning calorimetry data are used to monitor the progress of cure and are compared with the dielectric data. System [A] is a simple epoxy amine system, whilst system [B] is a blend of both epoxy and amine resins. It is clear that without calibration of the dielectric data against other methods it is difficult to unambiguously derive absolute cure information on a system not previously studied. However, dielectric data does allow identification of the points at which gelation and vitrification occur and demonstrates its utility as an in situ monitoring method for the cure process.     

An Enhanced Water Solubility and Stability of Anthocyanins in Mulberry Processed with Hot Melt Extrusion

Mulberry fruits are rich sources of anthocyanins that exhibit beneficial biological activity. These anthocyanins become instable in an aqueous media, leading to their low bioavailability. In this study, a colloidal dispersion was produced by processing mulberry samples with hot-melt extrusion. In this process, hydrophilic polymer matrices were used to disperse the compound in an aqueous media. Mulberry samples were processed with hot-melt extrusion and in the presence of an ionization agent and sodium alginate to form mulberry-extrudate solid formulations. The particle size of mulberry-extrudate solid formulations decreased, while the total phenol content, the total anthocyanin content, and solubility increased. Fourier transform infrared spectroscopy (FT-IR) revealed that mulberry-extrudate solid formulations now contained new functional groups, such as –COOH group. We investigated whether mulberry-extrudate solid formulations had a positive impact on the stability of anthocyanins. The non-extrudate mulberry sample and mulberry-extrudate solid formulations were incubated with a simulated gastric fluid system and an intestinal fluid system. The number of released anthocyanins was determined with HPLC. We found that anthocyanins were released rapidly from non-extrudate mulberry extract. Mulberry-extrudate solid formulations contained a large number of available anthocyanins even after being incubated for 180 min in the intestinal fluid system. Thus, hot-melt extrusion enhanced water solubility and stability of anthocyanins with the prolonged release.     

Qualitative and quantitative contaminants assessment in recycled pellets from post-consumer plastic waste by means of spectroscopic and thermal characterization

The complexity of any plastic recycling initiative lies in the heterogeneous nature of the post-consumer commingled plastic waste stream: recycling treatments are challenging without prior reliable sorting. A suitable identification system should be able to recognize different plastics and blends. Nowadays, the main technique used as quality control in plastic waste sorting centers is differential scanning calorimetry, whose result can be purely qualitative or semi-quantitative, since only the crystalline fraction is evaluated. Moreover, the time required for data acquisition is relatively long. Infrared spectroscopy is an alternative, faster technique extensively used in applied research, but not widely utilized in industry. In this work, the cross-use of infrared spectroscopy and calorimetry is tested in a real, practical case: the quality control of recycled pellets (namely composed of polyolefins only), which represent the output of a commingled plastic recycling plant and are used as secondary raw materials for different applications. Appropriate infrared spectroscopy calibration curves were built to allow the quantitative analysis with respect to the most common polymers found in the commingled plastic waste stream; the composition and contaminants in the recycled pellets were thereby determined and tracked through different production batches through the cross-use of the two techniques outlined above.     

Updates on biogas enrichment and purification methods: A review

The market for biogas production has been increasing every year all over the world. The use of biogas as an energy vector is accomplished through the most diverse applications, such as direct burning (thermal energy), internal combustion engines, and fuel cells. Besides direct applications, biogas can be used as a raw material for producing high added-value products, such as molecular hydrogen and renewable hydrocarbons, through a new enterprise concept, the biorefineries. Purity and quality control are determinant factors that enable the decision-making regarding the end use of biogas. Physical, chemical, and biological methods can be used in biogas upgrading processes as well as a combination of different techniques. This review aims to deepen the knowledge about relevant technologies for biogas purification. It also addresses the most efficient and feasible methods, challenges to be overcome, and main demands for future studies. Therefore, the presentation, in a detailed way, of the synergistic effects caused by components contained in natural biogas and the combinatorial methods for removing these contaminants, differentiates this from other works that approach only the purification techniques but do not point out their problems and causes more comprehensively. Thus, studies related to the combined effects of contaminants would be interesting in future works.     

Drug and Protein Encapsulation by Emulsification: Technology Enhancement Using Foam Formulations

Significant progress has been made in developing formulations for protein and drug encapsulation and delivery. The most frequently used method is the emulsion/solvent removal technology, where microencapsulation of proteins in polymeric matrices can be easily achieved with a simple stirrer setup. However, it remains a challenge to produce protein‐encapsulated formulations with high encapsulation efficiencies. The emulsion/solvent removal technique and the relevant formulation and process parameters that govern the protein encapsulation processes are reviewed. A new encapsulation method of using foam as a delivery medium during the preparation of protein‐loaded microparticles is proposed. The foam characteristics of direct relevance to protein encapsulation are discussed. The unique properties of foam could enhance intermolecular interactions and access to internal pore surfaces, thus making them superior compared to traditional methods employing aqueous liquid phases during protein encapsulation.     

Sources and impacts of pharmaceutical components in wastewater and its treatment process: A review

Pharmaceutical compounds and their derivatives are major pollutants in the environment, as their metabolites affect the terrestrial as well as aquatic organisms in one or another way. In recent times, many papers have discussed the treatment procedures for single pharmaceutical and mixture of pharmaceutical components, but only few papers have discussed the fate and the exposure of pharmaceutical contaminants in our environment. In this paper, we discuss the sources and the forms of pharmaceutical products and their resultant in the environment and their addition to the microbial and to human communities. A detailed discussion of various treatment techniques from conventional to current techniques, their advantages and disadvantages is given here. Researchers are finding the techniques in order to completely degrade the contaminants and their transformed products from the environment. Among the technique, s nanotechnology was found to be an efficient technique, and the combination of nanotechnology with other conventional technologies gives higher removal efficiency.     

Performance of polyurea formulations against impact loads: A molecular dynamics and mechanical simulation approach

Today, polyurea is known as one of the most famous and widely used protective coatings in the world. The unique properties of polyurea are at such a high level that it is possible to use this coating in a wide range of applications. Although polyurea is generally made from the reaction between two types of precursors (diisocyanate and diamine), it is challenging to choose the right precursor pair for producing a coating with a specific application due to the great variety of introduced diisocyanate and diamine precursors. On the other hand, the experimental synthesis of the formulations and the study of their performance is also very costly and time-consuming. In this study and by examining a series of commercially available precursors for polyurea coatings synthesis, well-known materials have been introduced and classified. Then, a representative of each formulation family is simulated by a molecular dynamics and mechanical approach using a three-step method on atomic, meso, and continuum scales, and the mechanical properties of the formulations are extracted. Then, by examining the response of each formulation to the three types of dynamic load (earthquake, projectile impact, and air blast), the protective capabilities of these formulations have been compared, and the optimal formulation for each application has been introduced.