Monodisperse, hypercrosslinked polymer microspheres as tailor-made sorbents for highly efficient solid-phase extractions of polar pollutants from water samples

Chromatographic Methods for the Determination of Organic Pollution in Urban Water: A Current Mini Review

The number of pollutants and chemicals with the potential to reach the environment is still largely unknown, which poses great challenges for researchers in various fields of science, environmental scientists, and analytical chemists. Chromatographic techniques, both gas chromatography (GC) and liquid chromatography (LC) coupled with different types of detection, are now invaluable tools for the identification of a wide range of chemical compounds and contaminants in water. This review is devoted to chromatographic techniques GC-MS, GC-Orbitrap-MS, GC-MS/MS, GC-HRMS, GC × GC-TOFMS, GC-ECD, LC-MS/MS, HPLC-UV, HPLC-PDA, UPLC-QTOFMS, used to determinate emerging organic contaminants in aquatic media, mainly in urban water, published in the scientific literature over the past several years. The article also focuses on sample preparation methods used in the analysis of aqueous samples. Most research focuses on minimizing the number of sample preparation steps, reducing the amount of solvents used, the speed of analysis, and the ability to apply it to a wide range of analytes in a sample. This is extremely important in the application of sensitive and selective methods to monitor the status of urban water quality and assess its impact on human health.

Materials for Solid-Phase Extraction of Organic Compounds

This review provides an overview of the most recent developments involving materials for solid-phase extraction applied to determine organic contaminants. It mainly concerns polymer-based sorbents that include high-capacity, as well as selective sorbents, inorganic-based sorbents that include those prepared using sol-gel technology along with structured porous materials based on inorganic species, and carbon nanomaterials, such as graphene and carbon nanotubes. Different types of magnetic nanoparticles coated with these materials are also reviewed. Such materials, together with their main morphological and chemical features, are described, as are some representative examples of their application as solid-phase extraction materials to extract organic compounds from different types of samples, including environmental water, biological fluids, and food.

Highly Porous Organic Polymers for Hydrogen Fuel Storage

Hydrogen (H2) is one of the best candidates to replace current petroleum energy resources due to its rich abundance and clean combustion. However, the storage of H2 presents a major challenge. There are two methods for storing H2 fuel, chemical and physical, both of which have some advantages and disadvantages. In physical storage, highly porous organic polymers are of particular interest, since they are low cost, easy to scale up, metal-free, and environmentally friendly. In this review, highly porous polymers for H2 fuel storage are examined from five perspectives: (a) brief comparison of H2 storage in highly porous polymers and other storage media; (b) theoretical considerations of the physical storage of H2 molecules in porous polymers; (c) H2 storage in different classes of highly porous organic polymers; (d) characterization of microporosity in these polymers; and (e) future developments for highly porous organic polymers for H2 fuel storage. These topics will provide an introductory overview of highly porous organic polymers in H2 fuel storage.

Synthesis of a novel isatin and ethylenediamine modified resin and effective adsorption behavior towards Orange G

In this study, a novel crosslinked resin 135-I-EDA modified by isatin and ethylenediamine was synthesized through two continuous functionalization steps using chloromethylated styrene-divinylbenzene copolymer as the substrate. In the first step, the cross-linking reaction and isatin incorporation were realized in a creative one-pot reaction using Friedel-crafts reaction in the presence of isatin to give resin 135-I; in the second step, ethylenediamine was successfully introduced on the carbonyl of the modified isatin to further increase the chemically interacting sites. The double-modified resin 135-I-EDA displayed the best adsorption performance (113.38 mg g-1) towards Orange G, which is 1.99 times and 3.49 times as much as that of 135-I (56.94 mg g-1) and commercial resin H-103 (32.51 mg g-1) respectively. This is attributed to its superior porous structure formed in the Friedel-crafts reaction and multiple modified groups in isatin and ethylenediamine. π-π conjugation and hydrogen bonding are the main driving forces for the adsorption. The pseudo-second-order rate equation characterizes the adsorption kinetic curves well and 135-I-EDA displayed the fastest adsorption rate. The study also proved that the 135-I-EDA has a better adsorption capacity for OG in more acidic solution, at higher temperature and higher salinity, which provides a basis for the treatment of industrial dye wastewater.

Hypercrosslinked porous polymer materials: design, synthesis, and applications

Hypercrosslinked polymers (HCPs) are a series of permanent microporous polymer materials initially reported by Davankov, and have received an increasing level of research interest. In recent years, HCPs have experienced rapid growth due to their remarkable advantages such as diverse synthetic methods, easy functionalization, high surface area, low cost reagents and mild operating conditions. Judicious selection of monomers, appropriate length crosslinkers and optimized reaction conditions yielded a well-developed polymer framework with an adjusted porous topology. Post fabrication of the as developed network facilitates the incorporation of various chemical functionalities that may lead to interesting properties and enhance the selection toward a specific application. To date, numerous HCPs have been prepared by post-crosslinking polystyrene-based precursors, one-step self-polycondensation or external crosslinking strategies. The advent of these methodologies has prompted researchers to construct well-defined porous polymer networks with customized micromorphology and functionalities. In this review, we describe not only the basic synthetic principles and strategies of HCPs, but also the advancements in the structural and morphological study as well as the frontiers of potential applications in energy and environmental fields such as gas storage, carbon capture, removal of pollutants, molecular separation, catalysis, drug delivery, sensing etc.

Macroporous materials: microfluidic fabrication, functionalization and applications

This article provides an up-to-date highly comprehensive overview (594 references) on the state of the art of the synthesis and design of macroporous materials using microfluidics and their applications in different fields.

New trends in sample preparation techniques for environmental analysis

Environmental samples include a wide variety of complex matrices, with low concentrations of analytes and presence of several interferences. Sample preparation is a critical step and the main source of uncertainties in the analysis of environmental samples, and it is usually laborious, high cost, time consuming, and polluting. In this context, there is increasing interest in developing faster, cost-effective, and environmentally friendly sample preparation techniques. Recently, new methods have been developed and optimized in order to miniaturize extraction steps, to reduce solvent consumption or become solventless, and to automate systems. This review attempts to present an overview of the fundamentals, procedure, and application of the most recently developed sample preparation techniques for the extraction, cleanup, and concentration of organic pollutants from environmental samples. These techniques include: solid phase microextraction, on-line solid phase extraction, microextraction by packed sorbent, dispersive liquid-liquid microextraction, and QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe).

Experimental mixture design as a tool for the synthesis of antimicrobial selective molecularly imprinted monodisperse microbeads

The effect of the cross-linker on the shape and size of molecular imprinted polymer (MIP) beads prepared by precipitation polymerization has been evaluated using a chemometric approach. Molecularly imprinted microspheres for the selective recognition of fluoroquinolone antimicrobials were prepared in a one-step precipitation polymerization procedure using enrofloxacin (ENR) as the template molecule, methacrylic acid as functional monomer, 2-hydroxyethyl methacrylate as hydrophilic comonomer, and acetonitrile as the porogen. The type and amount of cross-linker, namely ethylene glycol dimethacrylate, divinylbenzene or trimethylolpropane trimethacrylate, to obtain monodispersed MIP spherical beads in the micrometer range was optimized using a simplex lattice design. Particle size and morphology were assessed by scanning electron microscopy, dynamic light scattering, and nitrogen adsorption measurements. Electron paramagnetic resonance spectroscopy in conjunction with a nitroxide as spin probe revealed information about the microviscosity and polarity of the binding sites in imprinted and nonimprinted polymer beads.

The effect of molecular weight on the porosity of hypercrosslinked polystyrene

Microporous polymers can be prepared by crosslinking polystyrenes, with the surface areas being dependent on the degree of polymerisation.

Hypercrosslinked materials: preparation, characterisation and applications

Hypercrosslinked materials have experienced a great expansion in both the synthetic approach and the field of applications.