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A sustainable and recycling strategy for the disposal of e-waste with a magnetic core stirring rod adsorbent.

Nanotechnology is rapidly sweeping through all the vital fields of science and technology such as electronics, aerospace, defense, medicine, and catalysis. It involves the design, synthesis, characterization, and applications of materials and devices on the nanometer scale. At the nanoscale, physical and chemical properties differ from the properties of the individual atoms and molecules of bulk matter. In particular, the design and development of silica nanomaterials have captivated the attention of several researchers worldwide. The applications of hybrid silicas are still limited by the lack of control on the morphology and particle size. The ability to control both the size and morphology of the materials and to obtain nano-sized silica particles has broadened the spectrum of applications of mesoporous organosilicas and/or has improved their performances. On the other hand, adsorption is a widely used technique for the separation and removal of pollutants (metal ions, dyes, organics,...) from wastewater. Silica nanoparticles have specific advantages over other materials for adsorption applications due to their unique structural characteristics: a stable structure, a high specific surface area, an adjustable pore structure, the presence of silanol groups on the surface which allow easy modification, less environmental harm, simple synthesis, low cost, etc. Silica nanoparticles are potential adsorbents for pollutants. We present herein an overview of the different types of silica nanoparticles going from the definitions to properties, synthetic approaches and the mention of potential applications. We focus mainly on the recent advances in the adsorption of different target substances (metal ions, dyes and other organics).

Metal-organic frameworks (MOFs) featured with flexible design and versatile properties are finding increasing applications. In particular, integrating multiple functions into one framework can bring them improved detection efficiency towards various analytes. Herein, for the first time, a Fe-Zr bi-metal-organic framework (UiO-66(Fe/Zr)-NH2) with three functions (intrinsic fluorescence, peroxidase-mimicking activity, and specific recognition) is designed to establish a ratiometric fluorescent platform for high-performance phosphate ion (Pi) sensing. The use of a fluorescent organic ligand endows the MOF material with a strong intrinsic fluorescence at 435 nm. The presence of Fe3+/Fe2+ nodes offers good enzyme-like capacity to catalyze the o-phenylenediamine (OPD) substrate to fluorescent OPDox (555 nm), which then quenches the intrinsic fluorescence of UiO-66(Fe/Zr)-NH2 due to the inner filter effect. The Zr4+ nodes in the MOF material act as selective sites for Pi recognition. When Pi exists, it specifically adsorbs onto UiO-66(Fe/Zr)-NH2 and decreases the latter's peroxidase-mimetic activity, resulting in the less production of fluorescent OPDox. As a consequence, the intrinsic fluorescence of UiO-66(Fe/Zr)-NH2 at 435 nm is restored, and the signal from OPDox at 555 nm is reduced inversely. With the ratiometric strategy, efficient determination of Pi with outstanding sensitivity and selectivity was realized, giving a detection limit down to 85 nM in the concentration range of 0.2-266.7 μM. Accurate measurement of the target in practical water matrices was also validated, indicating its promising application for Pi analysis in environmental and other fields.

In recent years, there has been rapid growth of enzyme-mimicking catalytic nanomaterials (nanozymes). Compared with biological enzymes, nanozymes exhibit several superiorities, including robust activity, easy production, and low cost, which endow them with promising applications in biochemical analysis. As an emerging member of nanozymes, metal-organic framework (MOF) nanozymes are attracting growing attention because of their composition and structural characteristics. Rationally designing MOFs with enzyme-like catalytic ability is opening up a new avenue for biochemical detection. In this Feature Article, we summarize the latest developments of MOF nanozymes and their applications in biochemical sensing. First, the types of nanozymes derived from MOFs are categorized, and effective strategies to improve the weak activity inherent in MOF nanozymes are introduced. Then, the multi-functionalization of MOFs with enzyme mimic activity and other attractive properties is emphasized. After that, the typical applications of MOF nanozymes in the detection of various analytes are rigorously reviewed. Finally, the current challenges and some development directions in this field are discussed. It is believed that the versatile nature of MOFs will bring a bright future for MOF nanozymes in biochemical analysis.

Potentially toxic dichlorophenols and heavy metal ions commonly coexist in industrial sewage, posing a serious threat to public health and the environment and making the treatment more challenging. Inspired by Suzhou bifacial embroidery, whereby the Janus-like planar structure allows different compositions to be compartmentalized onto two distinct surfaces, Janus silica nanosheets partitioning bispecific artificial receptors (i.e., molecularly imprinted sites and thiol groups) onto distinct recognition surfaces (J-MIPs/cys) were designed to independently take up 2,6-dichlorophenol (DCP) and Pb(II). For J-MIPs/cys, the thiol groups are expected to capture Pb(II) via chelating action and molecularly imprinted cavities act as highly specific recognition sites for DCP. J-MIPs/cys possessed uniform cross-sectional dimensions and thickness (∼25.3 nm), and a particle-like surface imprinted layer (∼21.8 nm). In the monocomponent system, J-MIPs/cys displayed fast binding kinetics (60 min and 45 min), large monolayer adsorption capacity (129.4 mg g−1 and 82.95 mg g−1), high affinity, and excellent regeneration after five reuse cycles (9.134% and 12.16% loss in adsorption amounts) for DCP and Pb(II), respectively. Additionally, a spontaneous and endothermic adsorption process was also confirmed. In a binary system, the presence of Pb(II) produced a prominent increase in DCP adsorption at high initial concentrations and a decrease at low initial concentrations, owing to the partial complexation of Pb(II) with excess DCP and occupation of imprinted sites by Pb(II). However, the uptake of Pb(II) was inhibited over the whole range of concentration in the presence of DCP due to the competitive adsorption onto thiol groups. In summary, J-MIPs/cys integrating novel bispecific receptors open wide possibilities for efficient and specific treatment of coexisting toxic pollutants.

In this work, we report a novel naked-eye and fluorescent dual-readout glucose sensing platform based on the bifunctional peroxidase mimicking and ON-OFF fluorescence of Pd nanoparticle-decorated graphitic C3N4 nanosheets (PdNPs/g-C3N4). The PdNPs/g-C3N4 hybrid not only exhibited a strong peroxidase-like activity to catalyze colorless o-phenylenediamine (OPD) into its yellow product OPDox in the presence of H2O2, but it also acted as a turn-off fluorescent sensor for the assembly of the generated OPDox on g-C3N4. When coupled with glucose oxidase (GOx), the platform could provide both visual and fluorescent responses for glucose specifically. Under optimal conditions, the platform was able to detect the target at concentrations as low as 50 μM and 0.4 μM in the linear ranges of 50-2000 μM and 1-1000 μM with the naked eye and a fluorometer, respectively. The developed platform integrates the equipment-free merit of naked-eye observation with the excellent performance of fluorometric analysis well, providing a new and powerful tool for both rough assessment and accurate detection of glucose in diabetes management and other applications.

In this work, a new colorimetric strategy based on the specific chromogenic interaction between Fe3+ and ascorbic acid 2-phosphate was proposed for the highly selective, repeatable, and accurate detection of alkaline phosphatase with extremely simple operation and low cost.

As a typical biomarker for disease diagnosis in clinical practice, alkaline phosphatase (ALP) plays a critical role in regulating the dephosphorylation process of biomolecules. On this account, exploration of an effective and simple means of ALP activity measurement becomes very significant. In this work, we report a catalytic reaction-based colorimetric method for the monitoring of ALP activity via employing nanostructured MnO2 as a favorable oxidase mimic. The prepared MnO2 microspheres exhibit good oxidase-like capacity to induce the catalytic oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to deep-blue TMBox; when ALP hydrolyzes ascorbic acid phosphate, the produced ascorbic acid (AA) with a certain reducing power can destroy the MnO2 enzyme mimic by reducing it to Mn2+, dramatically suppressing the TMB chromogenic reaction. Based on the strategy, a convenient and high-performance colorimetric method was established for ALP activity sensing, giving a wide linear range from 0.5 to 120 U L−1. With the help of N-ethylmaleimide as an efficient masking agent for biothiols, the colorimetric approach could provide excellent specificity for ALP activity detection. Reliable and precise measurement of the analyte in practical samples was also verified by our assay, indicating its promise as a feasible tool for clinical diagnosis.

A facile strategy to fabricate crown ether (2-methylol-12-crown-4, 2M12C4) immobilized porous polymers (PGMA-CE) was reported toward lithium(I) (Li+) recovery. Macroporous polymer foam (polymeric glycidyl methacrylate, PGMA) with abundant epoxy groups was firstly prepared as a support using a high internal phase emulsion (HIPE) template. And then 2M12C4 was covalently attached onto the surface of PGMA to endow the PGMA-CE with good stability and high selectivity. PGMA-CE was characterized by SEM, FT-IR, XPS, and 13C NMR spectroscopy, and its porous structure and the successful introduction of 2M12C4 were confirmed. In batch mode experiments under optimum conditions, PGMA-CE exhibited fast adsorption kinetics (the equilibrium time was 3.0 h), and the kinetics data were well described using a pseudo-second-order model. A Langmuir-type monolayer adsorption was investigated, and the calculated maximum equilibrium adsorption capacity was 3.15 mg g−1. In addition, PGMA-CE displayed excellent selectivity for Li+ in the presence of multiple interfering ions (Na+, K+, Mg+, and Ca2+), and the selective separation factors (α) were above 4.75. Regeneration analysis showed that the adsorption capacity of PGMA-CE toward Li+ after five cycles was 91.8% of the first cycle.

A metal-organic framework (CuBDC) that possesses cascade cysteine oxidase- and peroxidase-mimicking activities and stimulus-responsive fluorescence was designed by coordinating cupric ions with terephthalic acid. The three-in-one CuBDC provided a new and extremely convenient turn-on fluorescence platform for selective and reliable detection of cysteine.

Magnetic microspheres (Fe3O4@PVIM@Zn(II)) composed of a high magnetic-response Fe3O4 core and a Zn(II)-immobilized cross-linked polyvinyl imidazole (PVIM) shell via reflux-precipitation polymerization and metal-ion affinity strategy were fabricated. Integrating the advantages of specific uptake and fast separation, Fe3O4@PVIM@Zn(II) was adopted as an ideal pathway for luteolin (LTL) recognition. As-prepared Fe3O4@PVIM@Zn(II) possessed core–shell structure, uniform size (200 nm), high magnetic responsiveness (32.6 emu g−1), and a very easy synthesis process. X-ray photoelectron spectroscopy (XPS) suggested a strong interaction between the nitrogen heterocyclic ring of PVIM and Zn(II), which produced abundant binding sites for LTL. The batch mode experiments can be well described by pseudo-first-order kinetic models and a Langmuir isotherm. A rapid binding equilibrium (within 45 min) and large monolayer adsorption capacity (23.92 mg g−1) at 298 K were also observed. In addition, Fe3O4@PVIM@Zn(II) displayed remarkable selectivity to LTL; the purification process using Fe3O4@PVIM@Zn(II) can make purified LTL from approximately 85% to 94.26%. The antibacterial activity of purified LTL was outstanding by means of a Staphylococcus aureus (ATCC29213) resistance experiment. Considering its multiple merits, Fe3O4@PVIM@Zn(II) exhibited great potential for specific binding with natural products, such as flavonoids.

Hydrophilic urea-formaldehyde macroporous foams (UFMF) were simply synthesized by templating oil-in-water Pickering high internal phase emulsions (HIPEs) solely stabilized by lignin particles. Morphology and structure of the UFMF can be easily tailored by varying the experimental compositions of Pickering HIPEs and polymerization time. Due to their porous matrix, hydrophilic surface, and high content of binding groups (such as hydroxyl groups and carbonyl groups), as-prepared UFMF was adopted for the removal of three phenolic compounds (PCs) from aqueous solution. The influences of pH, solution temperature, contact time, and initial concentration of 2,4,5-trichlorophenol (2,4,5-TCP), 2,4,6-trichlorophenol (2,4,6-TCP) and 4-nitrophenol (4-NP) on adsorption capacity and competitive adsorption of multi PCs were investigated via the batch mode experiments. The adsorption kinetics and adsorption isotherms fit well by a pseudo-second-order model and Langmuir model, respectively. The max adsorption capacity of 2,4,5-TCP, 2,4,6-TCP and 4-NP at 25 °C are 116.3 mg g−1, 78.74 mg g−1, 29.41 mg g−1, respectively, and their adsorption rate follows the order 2,4,5-TCP > 2,4,6-TCP > 4-NP. Moreover, the group type and position effects both influence the adsorption, and follow the order: 2,4,5-position substitution of chloride > 2,4,6-position substitution of chloride > 4-position substitution of nitro-group, showing that the substitution with the more groups has the higher adsorption affinity.

A straightforward, one-pot approach for novel ion imprinted mesoporous silica materials (IMS) has been developed by co-condensation. IMS was used for the recovery of dysprosium through solid–liquid extraction in an acidic system. The dysprosium adsorption of IMS was efficiently modeled using a pseudo-second order rate equation. The initial kinetics of adsorption was fast, and almost complete adsorption was observed after 150 min. Adsorption isotherms were efficiently modeled using the Langmuir equation. The adsorption capacity of IMS toward dysprosium was 22.33 mg g−1 at pH = 2.0, which was apparently greater than the adsorption capacity of non-imprinted materials at pH = 5.0. The value of the imprint factor at pH = 2.0 was higher than the other pH obviously. The distribution coefficient relative to dysprosium was 539 mL g−1, which was significantly higher than that of other rare earth ions. IMS demonstrates enhanced selectivity towards dysprosium compared to non-imprinted materials in an acidic solution via solid–liquid extraction, which substantially improves the selective extraction process and provides a greener alternative to liquid–liquid extraction. In addition, the materials demonstrated a high degree of reusability over five extraction–stripping cycles, enhancing their potential for application in real rare earth metal recycling in acidic systems.

In the field of oil/water separation, functional oil-absorbing materials with both controllable porous structures and swelling properties are highly desirable. In the present study, we report a novel strategy for fabricating Mg–Al porous fiber (Mg–Al PF)/polyurethane (PU) foam composites using a combined biotemplate method and foaming technology, and discuss their application in the absorption of oils and organic solvents. The Mg–Al PF composites with a hierarchical porous structure are fabricated based on nanoplatelets on the surfaces of microscale inorganic fibers. The PU foam composites with excellent oil swelling properties are synthesized by addition of Mg–Al PF composites to PU foams. In order to enhance the hydrophobic and oleophilic properties, the surfaces of Mg–Al PF composites are chemically modified using silane coupling agent (KH 570). The surface modified Mg–Al PF composites show high repellency towards water with a water contact angle of 146.6°. Owing to their unique pore structures and superhydrophobic and swelling properties, the foam composites can remove oils and organic solvents from water with high selectivity and absorption capacity, and can absorb not only floating oil but also heavy organic solvents underwater. In general, the absorption capacities of the PU foam composites for oils and organic solvents are 5.06–44.81 times their own weight, partly depending on the density and viscosity of the absorbate. The PU foam composites still maintain relatively consistent absorption properties for oil and organic solvent absorption after 10 cycles. These outstanding properties potentially make the as-prepared PU foam composites promising candidates for practical oil absorption and oil/water separation.

With the booming requirements for diabetes management, food quality control, and bioprocess inspection, monitoring of glucose in various matrices has drawn unprecedented interest of both academic and industrial researchers recently. As a relatively new class of glucose sensors, enzyme-free detection of the target is capable of providing several fascinating characters such as ultra-high sensitivity, excellent stability, and simple fabrication. Considering the rapid expansion of the glucose determination field without using any biological enzymes, here we focus our attention on updating the latest advances in non-enzymatic electrochemical glucose sensors based on non-noble transition metal materials achieved in the past few years. In this minireview, both the superiorities and the intrinsic drawbacks of detecting glucose by employing non-precious materials including Ni, Cu, Co, Mn, and Fe are intensively highlighted, followed by a systematic discussion on the important progress harvested for enzymeless glucose sensing. Finally, the potential opportunities of non-noble transition metal materials in fabricating high-performance enzyme-free glucose sensors are given, and the current challenges for their practical applications are also summarized.

Many rivers and lakes contain excess phosphate, which would cause a series of environmental problems. A novel Fe–La modified magnetic hierarchical porous silica was synthesized by an impregnation method to adsorb phosphate in aquatic ecology. Scanning electron microscopy and transmission electron microscopy suggested the structure of the adsorbent was a core–shell structure. Fourier transform infrared spectroscopy and low-angle powder X-ray diffraction indicated that adsorbents were successfully modified by Fe oxide and La oxide. After loading Fe oxide and La oxide on the material, N2 adsorption–desorption studies showed that the specific surface area was 52.4 m2 g−1. Moreover, the adsorbents possessed the desired property of a magnet and easy separation from the solution by testing with a vibrating sample magnetometer. The adsorption process was highly pH-dependent and the appropriate adsorption pH range was about 3.0–6.0. And the resulting adsorption isotherms of the sorbent was better represented by the Langmuir model than the Freundlich model, and the adsorption capacity of the adsorbent was as high as 71.99 mg P per g, which was much higher than most other adsorbents (most La-doped adsorbents' adsorption capacities are under 25 mg P per g). Furthermore, adsorption kinetics studies showed that the adsorption fitted the pseudo-second order model well. Also a high selectivity of phosphate was observed in the coexisting anions system. The proposed adsorbent demonstrated a higher degree of reusability in a cycle test.

Herein we report a novel synthetic strategy for fabrication of microcellular foam catalysts (MFCs) with hydrophobic, acid–base, and hierarchical porous properties for conversion of one-pot cellulose to a key chemical platform (i.e. 5-hydroxymethylfurfural, HMF) for biofuels. The water-in-oil (W/O) Pickering high internal phase emulsions (HIPEs), stabilized by both amino-functionalized nanoparticles (namely, S-NH2) and Span 80, were used as the template for simultaneous polymerization of oil phase containing 1-octene, divinylbenzene (DVB), and trihydroxymethylpropyl trimethylacrylate (TMPTMA). After subsequent sulfonation process, acid and base sites resulting from grafted –SO3H group of polydivinylbenzene (PDVB) and S-NH2 were both located on the surface of the MFCs. The resultant MFCs composite had a typical hierarchical porous structure, and the macropores with a well-defined open-cell and interconnecting pore throat structure could be controlled via the composition of the oil phase of emulsion, with the mesopore structure closely related to the degree of cross-linking of oil-soluble functional monomer. The representative catalyst MFCs-3 had a hierarchical porous structure (macropores ranging from 1.0 µm to 30 µm and uniform mesopores in 32.1 nm), hydrophobic surface (water contact angle of 125°), 0.735 mmol g−1 of base, and 1.305 mmol g−1 of acid. The HMF yield of 41% for cellulose conversion showed its excellent catalytic performance. This work opens up a route for simple and controlled fabrication of multifunctional polymeric catalysts for biomass energy conversion.

This review summarizes state-of-the-art progress in the molecular dynamics (MD) simulation of the novel thermal properties of graphene. The novel thermal properties of graphene, which include anisotropic thermal conductivity, decoupled phonon thermal transport, thermal rectification and tunable interfacial thermal conductance, have attracted enormous interest in the development of next-generation nano-devices. Molecular dynamics simulation is one of the main approaches in numerical simulation of the novel thermal properties of graphene. In this paper, the widely used potentials of MD for modeling the novel thermal properties of graphene are described first. Then MD simulations of anisotropic thermal conductivity, decoupled phonon thermal transport, thermal rectification and tunable interfacial thermal conductance are discussed. Finally, the paper concludes with highlights on both the current status and future directions of the MD simulation of the novel thermal properties of graphene.

In this work, reduced graphene oxide (RGO)–CdS/ZnS heterostructure composites have been successfully synthesized by a hydrothermal method by assembling the CdS/ZnS heterostructure nanoparticles on RGO sheets and the reduction of GO occurs simultaneously. The as-prepared RGO–CdS/ZnS composites with the content of 15% RGO exhibit highly active photodegradation of TC. A possible mechanism for the enhanced photocatalytic activity has been discussed. The CdS/ZnS heterostructure facilitates the transformation of electrons, which is excited by light irradiation in the conduction band of CdS. RGO is supposed to be an electron transfer channel, which is used to reduce the recombination of electron–hole pairs, thus enhancing the photo-conversion efficiency. By profiting from the synergy of RGO and CdS/ZnS heterostructure, the photocatalysts not only show a better photocatalytic activity in tetracycline antibiotics but also prevent pure CdS or ZnS from photocorrosion. At last, RGO–CdS/ZnS shows remarkable stability and cyclic performances.

In this work, eggshell particles, an abundant source of waste and a natural inorganic–organic composite material, were found to be well suited to stabilize O/W Pickering emulsions, because the small amount of organic components in eggshell results in a near 90 degree contact angle θ (81.03°). Erythromycin-based molecularly imprinted polymers (EM-MIPs) whose surfaces were covered in eggshell particles were successfully synthesized through developing an eggshell-stabilized Pickering emulsion methodology, and interestingly and importantly in this work, the discarded eggshell particles were employed solely to stabilize an oil-in-water emulsion for the first time. The imprinting process was conducted through radical polymerization between the functional and polymeric monomers in the presence of template molecules (EM) and initiators. Various analytical approaches including Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and specific surface and pore size analysis were used to characterize the synthesized EM-MIPs, and the results sufficiently demonstrated the formation of approximately spherical and wrinkled imprinted polymer which showed thermal stability (especially below 250 °C) and a specific surface area of 81.3 m2 g−1. Attributed to the formation of the eggshell-stabilized Pickering emulsion structure, the as-prepared EM-MIPs not only exhibited outstanding adsorption capacities, but also showed an excellent selective adsorption effect toward EM molecules. The Langmuir isotherm model and pseudo-second-order kinetic model also strongly suggested that the chemical process was the rate-limiting step in the adsorption of EM. Moreover, we envision that the EM-MIPs and the synthesis strategy employed in this work could be utilized in a broad range of applications.

In this study, star-shaped porphyrin-cored poly(e-caprolactone)-b-poly(gluconamidoethyl methacrylate) block copolymers (SPPCL-PGAMA) were successfully obtained. The synthetic route was via the ring-opening polymerization (ROP) of e-caprolactone using a tetra-hydroxyethyl terminated porphyrin as a core initiator followed by the atom transfer radical polymerization (ATRP) of unprotected gluconamidoethyl methacrylate (GAMA) in 1-methyl-2-pyrrolidinone (NMP) solution at room temperature. The structure of the copolymer was thoroughly studied by nuclear magnetic resonance spectroscopy (NMR), Gel Permeation Chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Notably, the as-prepared SPPCL-b-PGAMA that formed different structures being used for drug delivery systems has been researched. Moreover, this copolymer can release singlet oxygen under light irradiation and the singlet oxygen could be used for photodynamic therapy. In particular, UV-vis analysis showed that SPPCL-b-PGAMA has a very specific recognition with Concanavalin A (Con A) which provides porphyrin-cored SPPCL-b-PGAMA block copolymers for targeted drug delivery.

Based on halloysite nanotubes (HNTs), precipitation polymerization and Pickering emulsion polymerization were firstly adopted to synthesize two composites i.e. HNTs–polystyrene(PSt)–polydivinylbenzene(DVB)(I) and HNTs–PSt–PDVB(II), respectively. After sulfonation by 98% H2SO4, two polymeric solid acid catalysts i.e. HNTs–PSt–PDVB–SO3H(I) and HNTs–PSt–PDVB–SO3H(II) were successfully prepared for conversion of one-pot cellulose to 5-hydroxymethylfurfural (HMF) in an ionic liquid 1-ethyl-3-methyl-imidazolium chloride ([EMIM]-Cl). Characterization of two catalysts showed that HNTs–PSt–PDVB–SO3H(I) possessed superior hydrophobicity, content of –SO3H groups, and total acidic amounts to those of HNTs–PSt–PDVB–SO3H(II), but with less very strong acidic sites and non-uniform morphology. Then the amount of the catalysts, reaction time and reaction temperature were optimized for cellulosic conversion over the two catalysts, and a maximum yield of 28.52% for HNTs–PSt–PDVB–SO3H(I) and 32.86% for HNTs–PSt–PDVB–SO3H(II) under the optimized conditions was obtained, indicating very strong acidic sites played a key role in cellulose conversion. In addition, the two as-prepared catalysts could be very easily recycled at least five times without significant loss of catalytic activity.

In this work, a facile and general protocol to synthesize molecularly imprinted microspheres (MIMs), combining reverse atom transfer radical polymerization with precipitation polymerization, is described. Well-tuned surface properties in the as-obtained microspheres were achieved through the “living” nature of the active ATRP-initiators present on the surface in order to further functionalize the microspheres with hydrophilic poly(2-hydroxyethyl methacrylate) (PHEMA) brushes. The presence of a PHEMA shell on the MIMs was confirmed by SEM, FT-IR and water contact angle studies, and some quantitative information is also provided. Batch adsorption experiments were carried out in pure water to investigate the equilibrium, kinetics and selectivity properties of the imprinted materials. The adsorption data of the ungrafted imprinted materials for sulfamethazine (SMZ) were fitted well to the Freundlich isotherm model. However, after grafting, the Langmuir isotherm fits the data better, mainly because of the changes to the surface properties that increase the hydrophilicity and suppress the hydrophobically driven non-specific interactions. The imprinted microspheres exhibit a large adsorption capacity, and are also specific to SMZ but non-specific to other antibiotics. The obtained materials also show rapid kinetics and great reusability and stability, displaying potential for practical applications for the selective removal of pollutants from aqueous environments.

Stable water-in-oil (W/O) Pickering high internal phase emulsions (HIPEs) with an internal phase volume fraction of 84.8% were first stabilized by both the hydrophobic silica nanoparticles and span 80. Then, based on the obtained Pickering HIPEs, several macroporous polymerized solid acid (PDVB-SS-X-SO3H, X = 0, 0.2, 0.6) were prepared by polymerizing divinyl benzene (DVB) and sodium p-styrenesulfonate (SS), and were subsequently combined with sulfonation in H2SO4. All the as-prepared PDVB-SS-X-SO3H possessed open-cell structure, interconnecting pores and strong acidity, and were adopted as catalysts to convert cellulose into 5-hydroxymethylfurfural (HMF) in the presence of [Emim]Cl-mediated solvents. The results showed a maximum yield of 29.6% for PDVB-SS-0.2-SO3H, 12.9% for PDVB-SS-0-SO3H and 15.5% for PDVB-SS-0.6-SO3H under the same condition within 2.0 h at 120 °C, suggesting that the pore sizes and strong acidic sites played a key role in cellulose conversion. PDVB-SS-X-SO3H can be very easily recycled at least four times without a significant loss of activity. This research opens up a new method to synthesize porous solid acid catalyst materials through Pickering HIPEs templates.

Star-shaped poly(L-lactide)-b-poly(ethylene glycol) (SPPLA-b-PEG) block copolymers with porphyrin cores were successfully synthesized from the ring-opening polymerization (ROP) of L-lactide initiated with a porphyrin core, followed by a coupling reaction with a hydrophilic PEG polymer shell. The structure of this novel copolymer was thoroughly studied by nuclear magnetic resonance spectroscopy (NMR), Gel Permeation Chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The SPPLA-b-PEG copolymer exhibits efficient singlet oxygen generation and displays high fluorescence quantum yields. Notably, the self-assembly of the as-prepared porphyrin-cored star-shaped copolymer into micelle-like structures provides the great potential of using this well-defined porphyrin core material for drug delivery systems. Particularly, doxorubicin-loaded SPPLA-b-PEG nanospheres exhibit pH-induced drug release properties.

This work addressed efficient one-pot conversion of cellulose to 5-hydroxymethylfurfural by porous solid acid in the presence of 1-ethyl-3-methyl-imidazolium chloride ([Emim]Cl). On the basis of stable water-in-oil pickering high internal phase emulsions (HIPEs), porous solid acid (HC-PDVB-SS-SO3H) was prepared by polymerizing divinylbenzene (DVB) and sodium p-styrenesulfonate (SS), succedent sulfonation in H2SO4 and hypercrosslinking process. HC-PDVB-SS-SO3H with a stable network exhibited mesopores within a macropore structure, high BET specific surface area and more super-strong acid sites. To test catalytic activity, the reaction conditions were optimized via response surface methodology, and the sequence of the three variables affecting HMF yield followed the order, temperature > reaction time > amount of catalyst. By comparing with the other as-prepared porous solid acid, it can also be concluded that BET specific surface area and super-strong acid site both played key roles in cellulose conversion. Moreover, HC-PDVB-SS-SO3H was very easily reused at least four times without significant loss of activity.

Magnetic molecularly imprinted microcapsules (MMIMs) were synthesized by Pickering emulsion polymerization. In this work, an oil-in-water Pickering emulsion stabilized by halloysite nanotubes (HNTs) was first established in the presence of a few hydrophilic Fe3O4 nanoparticles as magnetic separation carriers. The imprinting system was fabricated by radical polymerization and subsequent combination with functional and polymeric monomers in the oil phase. The formation mechanism of the Pickering emulsion and MMIMs is discussed in detail, and the as-prepared MMIMs are successfully evaluated as sorbents for the recognition of λ-cyhalothrin. The results demonstrated that the MMIMs exhibited magnetic sensitivity (Ms = 8.45 emu g−1), a hollow structure, a semipermeable external surface and excellent robustness. The batch mode experiments proved that the imprinting effect synchronously improved the adsorption kinetics and equilibrium for the MMIMs. The selective recognition experiments also suggested high affinity and selectivity of MMIMs towards λ-cyhalothrin over fenvalerate and diethyl phthalate.

Porous silica nanospheres were fabricated using a facile surface-protected etching strategy. Polyvinylpyrrolidone (PVP) was used as a protecting polymer adsorbed on the surface of silica nanospheres and NaOH was employed as an etching agent. Owing to the protective action of PVP and inhomogeneous etching, mesopores were created in the silica nanospheres. Then, based on a simple and economical wet-chemical route, highly luminescent YVO4:Eu3+ nanocrystals were then integrated onto the nanospheres to form a highly luminescent mSiO2/YVO4:Eu3+ composite material. This material, which combined the mesoporous structure of SiO2 and the strong red luminescence property of YVO4:Eu3+, could be used as a novel optosensing system. The structure, morphology, porosity, and optical properties of the materials were well characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, N2 adsorption/desorption, and photoluminescence spectra, and the optical stability and effect of pH on mSiO2/YVO4:Eu3+ were also evaluated. It was observed that λ-cyhalothrin (LC) could quench the luminescence of mSiO2/YVO4:Eu3+ in a concentration-dependent manner, which was best described by a Stern–Volmer-type equation. This study therefore demonstrated that the composite material could be potentially used as a probe to monitor the residues of LC in water.

By grafting –SO3H and Cr(III) onto the surface of treated attapulgite (ATP) and halloysite nanotubes (HNTs), two acid–chromic chloride bi-functionalized catalysts i.e. ATP–SO3H–Cr(III) and HNTs–SO3H–Cr(III) were successfully synthesized. Then the as-prepared catalysts were characterized by SEM, TEM, EDS, XPS, BET, NH3–TPD, nitrogen adsorption–desorption and TG analysis. The catalytic activities of the synthesized ATP–SO3H–Cr(III) and HNTs–SO3H–Cr(III) were evaluated for the conversion of one-pot cellulose to 5-hydroxymethylfurfural (HMF) in an ionic liquid ([EMIM]-Cl) system. The amount of catalyst, reaction time and reaction temperature were optimized for cellulosic conversion over the two catalysts, resulting in a maximum yield of 31.20% for ATP–SO3H–Cr(III) and 41.22% for HNTs–SO3H–Cr(III) under the optimized conditions. The clay supported catalysts developed in this work showed greatly improved performances in cellulose-to-HMF conversion over other solid catalysts. In addition, the prepared catalysts could be very easily recycled, at least three times for ATP–SO3H–Cr(III) and twice for HNTs–SO3H–Cr(III) without significant loss of activity.

In order to achieve the treatment of antibiotic pollutants by solid waste, and for the purpose of improving the selectivity while enhancing the photocatalytic efficiency, this work used fly-ash cenospheres (FC) (obtained from coal fly ash, a typical solid waste) as the carrier, o-phenylenediamine (OPD) as the imprinted functional monomer, a conductive polymerizable monomer, enrofloxacin hydrochloride (EH) as the molecular template and TiO2@magnetic floating fly-ash cenospheres (TMFFC) as the matrix material. A magnetic conductive imprinted photocatalyst (MCIP) was synthesized via surface imprinting technology and a one-pot photo-induced method. The as-prepared MCIP was extensively characterized by SEM, N2 adsorption–desorption analysis with the Brunauer–Emmett–Teller (BET) method, FT-IR, elemental analysis, TGA, UV-vis and vibrating sample magnetometry (VSM). The results showed that the MCIP possessed a hollow spherical structure, floating and magnetic separation properties (Ms = 9.16 emu g−1), the conductive polymer (POPD) was successfully introduced into the surface-imprinted layer, and the electrical conductivity of MCIP was 0.359 us cm−1. The photodegradation rate, pseudo-first-order constant and coefficient of selection were calculated in detail, and all these data indicated that the MCIP not only had higher photocatalytic efficiency for the degradation of EH compared with other photocatalysts (such as the traditional surface-imprinted photocatalysts and TMFFC), but also possessed better selection for adsorption and photodegradation of EH in single/binary antibiotic solution. The mechanism of selective photodegradation of EH was also investigated.

Fe3O4/Halloysite nanotube magnetic composites (MHNTs) were firstly prepared via an effective polyol-medium solvothermal method, and then the surface of the MHNTs was endowed with reactive vinyl groups through modification with 3-(methacryloyloxy)propyl trimethoxysilane (MPS). Based on the MHNTs-MPS, temperature responsive and magnetic molecularly imprinted polymers (t-MMIPs) were further synthesized by adopting methacrylic acid (MAA) and N-isopropylacrylamide (NIPAM) as the functional monomer and temperature responsive monomer, respectively. The as-prepared t-MMIPs were characterized by FT-IR, TEM, TGA and VSM, which indicated that the t-MMIPs exhibit magnetic sensitivity (Ms = 2.026 emu g−1), magnetic stability (especially in the pH range of 4.0–8.0) and thermal stability and are composed of an imprinted layer. The molecular interaction between 2,4,5-trichlorophenol (TCP) and MAA was investigated by 1H-NMR spectroscopy and ultraviolet absorption spectroscopy, which suggest that hydrogen bonding may be largely responsible for the recognition mechanism. The t-MMIPs were then applied to selectively recognise and release TCP molecules at 60 °C and 20 °C, respectively. The maximum amount of binding at 60 °C was 197.8 mg g−1 and 122.6 mg g−1 for t-MMIPs and temperature responsive and magnetic non-imprinted polymers (t-MNIPs), respectively. At 20 °C, about 32.3%–42.7% of TCP adsorbed by t-MMIPs was released, whereas 25.3%–39.9% of TCP was released by t-MNIPs. The selective recognition experiments demonstrated the high affinity and selectivity of t-MMIPs towards TCP over competitive phenolic compounds, and the specific recognition of binding sites may be based on the distinct size, structure and functional group to the template molecules.

This paper reports a molecularly imprinted polymers (MIPs) based fluorescence sensor which is synthesized by grafting MIP layers on the surface of ZnO nanorods embedded γ-Fe2O3 nanoparticles via activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). Methacrylic acid (MAA, functional monomer), 3-(trimethoxysilyl)propyl mathacrylate (MPS) modified γ-Fe2O3 (γ-Fe2O3/MPS, assistant magnetic monomer) and ethylene glycol dimethacrylate (EGDMA, cross-linking monomer) were co-polymerized in anisole at 313 K in the presence of sulfamethazine as a template molecule. Sulfamethazine was then solvent-extracted to obtain ZnO-grafted molecularly imprinted polymers (ZnO-MIPs). ZnO-MIPs were characterized by FE-SEM, TEM, FT-IR, TGA/DSC, VSM, fluorescence spectroscopy and Raman spectroscopy. It was observed that sulfamethazine can quench the luminescence of ZnO-MIPs in a concentration-dependent manner that can be described by a Stern–Volmer-type equation. ZnO-MIPs were used to determine sulfamethazine in a spiked pork sample with good recognition ability. This study therefore demonstrates the potential application in the recognition and separation of antibiotics based on molecularly imprinted polymers.

Magnetic composites (MCs) were achieved via coating a chitosan layer containing γ-Fe2O3 nanoparticles onto the surface of aldehyde-functionalized fly-ash-cenospheres. Based on these MCs, the magnetic molecularly imprinted polymers (MMIPs) were further synthesized and characterized, and used to selectively recognise bisphenol A (BPA) molecules. Owing to the intrinsic advantages of cross-linked chitosan, magnetic γ-Fe2O3 nanoparticles and spherical FACs, the results demonstrated that these spherical shaped MMIPs particles had magnetic sensitivity (Ms = 2.221 emu g−1) and magnetic stability (especially over the pH range of 6.0–12). Batch mode adsorption studies were carried out to investigate the specific adsorption equilibrium, kinetics and selective recognition. The Langmuir isotherm model was fitted well to the equilibrium data of the MMIPs, and the monolayer adsorption capacity of the MMIPs was 135.1 mg g−1 at 298 K. The kinetic properties of the MMIPs were well described by the pseudo-second-order equation, indicating the chemical process could be the rate-limiting step in the adsorption process for BPA. Selective recognition experiments demonstrated the high affinity and selectivity of MMIPs towards BPA over competitive phenolic compounds. The molecular interaction between BPA and methacrylic acid (MAA) was investigated by the 1H-NMR spectrum. Hydrogen bonding was proved to be mainly responsible for the recognition mechanism, and the specific recognition effect may be based on the distinct size, structure and functional group of the template molecules.