•An inorganic phosphorous acid-modified mesoporous SBA-15 was synthesized.•The composite possessed high surface area, lager pore size and pore volume.•There were abundant and highly accessible binding sites present on its surface.•The composite exhibited an exceptional performance for Gd(III) adsorption.The development of rare earth adsorbent with high adsorption capacity and rapid adsorption rate is one of the most important issues for enriching and recovering rare earth ions. In the present work, an inorganic phosphorous acid-modified mesoporous SBA-15 (P-SBA-15) was facilely synthesized by a simple and cost-effective post-grafting approach, and its adsorption behavior towards the rare earth ion Gd(III) was investigated. Benefiting from high specific surface area (669.7 m2·g−1), large pore size (9.1 nm), and the presence of abundant phosphorous acid groups (1.4 mmol·g−1) on the surface, the P-SBA-15 exhibited an excellent performance in terms of capacity and kinetics on adsorption of Gd(III). Under optimized conditions, the adsorption capacity of P-SBA-15 towards Gd(III) was up to 1.3 mmol·g−1 at 30 °C, which is the second highest value as compared with previously reported Gd(III) adsorbents. Moreover, the adsorption of Gd(III) onto P-SBA-15 was ultrafast, achieving adsorption equilibrium within only 2 min. Test of reusability revealed that this mesoporous adsorbent could be repeatedly used several times without significant loss in binding capacity. This work not only provides a new insight into the fabrication of phosphorous acid-functionalized mesoporous silica, but also demonstrates its prospective application in adsorptive removal and/or recovery of rare earth ions.Download high-res image (143KB)Download full-size image

The development of a heterogeneous catalyst with high catalytic activity and durability for H2O2-mediated oxidation is one of the most important industrial and environmental issues. In this study, a Mn(II)-doped TiO2 heterogeneous catalyst was developed for H2O2-mediated oxidation. The TiO2 substrate-dependent partial-redox behavior of Mn was identified on the basis of our density functional theory simulations. This unique redox cycle was induced by a moderate electron transfer from Ti to Mn, which compensated for the electron loss of Mn and finally resulted in a high-efficiency cycling of Mn between its oxidized and reduced forms. In light of the theoretical results, a Mn(II)-doped TiO2 composite with well-defined morphology and large surface area (153.3 m2 g–1) was elaborately fabricated through incorporating Mn(II) ions into a TiO2 nanoflower, and further tested as the catalyst for oxidative degradation of organic pollutants in the presence of H2O2. Benefiting from the remarkable textural features and excellent Mn cycling property, this composite exhibited superior catalytic performance for organic pollutant degradation. Moreover, it could retain 98.40% of its initial activity even in the fifth cycle. Our study provides an effective strategy for designing heterogeneous catalytic systems for H2O2-mediated oxidations.Keywords: H2O2-mediated oxidation; heterogeneous catalyst; high catalytic activity and durability; Mn(II)-doped TiO2; partial redox;

•A three-dimensionally porous graphene (3D-pGR) has been facilely fabricated.•The 3D-pGR has high surface area and large pore volume.•The planar π-configuration of 3D-pGR is advantageous for bilirubin adsorption.•The adsorption capacity of 3D-pGR for BSA-bonded bilirubin is extraordinary high.•This material has a negligible hemolysis effect.The development of bilirubin adsorbents with high adsorption efficiencies towards albumin-bonded bilirubin is still a considerable challenge. In this work, a three-dimensionally porous graphene (3D-pGR) has been fabricated through a simple carbon dioxide (CO2) activation of thermally exfoliated graphite oxide (EGO). Intriguingly, the resultant 3D-pGR material showed hierarchically micro-meso-macroporous structure, high specific surface area of up to 843 m2 g−1, and large pore volume as high as 2.71 cm3 g−1. Besides, the large planar π-configuration structure of 3D-pGR made it possible to compete effectively with albumin for bilirubin binding. Taking advantages of these fantastic characteristics, the 3D-pGR was demonstrated to be extraordinarily efficient for bilirubin removal from a bovine serum albumin (BSA)-rich solution. Under optimized conditions, the maximum adsorption capacity of 3D-pGR for BSA-bonded bilirubin was up to 126.1 mg g−1, which is not only significantly higher than the adsorption capacities of currently available adsorbents towards albumin-bonded bilirubin, but also superior to those of many reported adsorbents towards free bilirubin. In addition, the hemolysis assay of 3D-pGR indicated that this material had negligible hemolysis effect. Findings from this study may open up important new possibilities for removal of protein-bonded toxins.

The development of high-performance adsorbents for efficient removal of bilirubin from albumin-rich solution is still a considerable challenge. In this study, a magnetic nitrogen-doped porous carbon (m-NpC) was facilely synthesized through a simple one-pot route using the biomass chitosan and the iron salt Fe(NO3)3·9H2O as precursors, and NaCl as template agent, respectively. Intriguingly, the resulting m-NpC material showed a hierarchically micro–meso–macroporous structure, high surface area (289 m2 g−1), large pore volume (0.33 cm3 g−1), and good magnetic response. In particular, the basic site-rich surface of m-NpC obtained as a result of nitrogen doping could compete effectively with albumin for bilirubin binding. As such, the m-NpC was used as a magnetically separable bilirubin adsorbent and showed superior adsorption properties for bilirubin removal from a bovine serum albumin (BSA)-rich solution. Under optimized conditions, the maximum adsorption capacity of m-NpC was up to 72.4 mg g−1, which is significantly higher than the value achieved by magnetic non-nitrogen doped porous carbon (24.7 mg g−1), but also superior to those of many previously reported adsorbents for BSA-boned bilirubin removal. Moreover, as evidenced by hemolysis assay, this material exhibited only a negligible hemolysis effect. These results suggest that the composite developed in this work can be used as a promising adsorbent in blood purification application to mitigate the risk of excess bilirubin.

A novel magnetic imprinting nanotechnology for selective capture of Gd3+ from a mixed solution of rare earth ions was developed by simply adding Gd3+-imprinted chitosan/carbon nanotube nanocomposite (IIP-CS/CNT) and silica-coated magnetite nanoparticle (SiO2@Fe3O4). The IIP-CS/CNT was prepared for the first time via a facile “surface deposition–crosslinking” method, exhibiting a well-defined coating structure. Interestingly, the neighboring IIP-CS/CNT monomers were held together as bundles, like a network, containing abundant interstitial spaces. When IIP-CS/CNT and SiO2@Fe3O4 were dispersed in a mixed solution of rare earth ions, the magnetic SiO2@Fe3O4 submicrospheres would be trapped in or adhere to the IIP-CS/CNT network, leading to the magnetization of IIP-CS/CNT; meanwhile, Gd3+ ions could be selectively captured by the magnetized IIP-CS/CNT. Saturation adsorption capacity for Gd3+ was up to 88 mg g–1 at 303.15 K, which is significantly higher than the Gd3+ adsorption capacities for the reported rare earth ion-imprinted adsorbents over recent years. The selectivity coefficients relative to La3+ and Ce3+ were 3.50 and 2.23, respectively, which are very similar to those found for other reported CS-based imprinted materials. Moreover, the imprinted adsorbents could be easily and rapidly retrieved by an external magnetic field without the need of additional centrifugation or filtration, greatly facilitating the separation process. Test of reusability demonstrated that the magnetized IIP-CS/CNT could be repeatedly used without any significant loss in binding capacity. Overall, this work not only provides new insights into the fabrication of magnetic imprinted CS-based composite, but also highlights its application for selective adsorption toward rare earth ions.Keywords: Gd3+; imprinted nanocomposite; magnetically retrievable; selective adsorption;

•A simple and green method was proposed to prepare carbon nanomaterials.•The carbon product showed acid/base bifunctional surface with large surface area.•The carbon material could efficiently adsorb both cationic and anionic compounds.Nanostructured carbonaceous materials are extremely important in the nano field, yet developing simple, mild, and “green” methods that can make such materials possess large surface area and rich functional groups on their surfaces still remains a considerable challenge. Herein, a one-pot and environment-friendly method, i.e., thermal treatment (180 °C; 18 h) of water mixed with glucose and chitosan (CTS), has been proposed. The resultant carbonaceous nanomaterials were characterized by field emitting scanning electron microscope, N2 adsorption/desorption, Fourier transform infrared spectroscope, X-ray photoelectron spectroscopy, and zeta-potential analysis. It was found that, in contrast to the conventional hydrothermally carbonized product from pure glucose, with low surface area (9.3 m2 g−1) and pore volume (0.016 cm3 g−1), the CTS-added carbonaceous products showed satisfactory textural parameters (surface area and pore volume up to 254 m2 g−1 and 0.701 cm3 g−1, respectively). Moreover, it was also interestingly found that these CTS-added carbonaceous products possessed both acidic (–COOH) and basic (–NH2) groups on their surfaces. Taking the advantages of large surface area and –COOH/–NH2 bifunctional surface, the carbonaceous nanomaterials exhibited excellent performance for adsorptions of cationic compound (i.e., methylene blue) at pH 10 and anionic compound (i.e., acid red 18) at pH 2, respectively. This work not only provides a simple and green route to prepare acid/base bifunctional carbonaceous nanomaterials with large surface area but also well demonstrates their potential for application in adsorption.

•Novel mesoporous composites of natural polymer chitosan and SBA-15 were prepared.•The mesoporous composites showed good performance towards the uptake of acid red 18.•The effect of various parameters on the adsorption efficiency was studied.•The adsorption kinetics, equilibrium, and adsorption thermodynamics were evaluated.Polymer-modified mesoporous silica materials are of practical interest due to their great potential for adsorption-related applications. In the present work, composites of natural polymer chitosan (CTS) and siliceous mesoporous SBA-15, i.e. SBA-15/CTS(5%), SBA-15/CTS(10%), and SBA-15/CTS(20%), were facilely prepared by prehydrolysis of tetraethyl orthosilicate in the presence of pore-directing agent and subsequent cocondensation with an appropriate amount of CTS-based organosilane. The texture and composition of pure SBA-15 and CTS-functionalized mesoporous products were characterized using various techniques such as TEM, XRD, N2 adsorption/desorption, 29Si MAS NMR, FT-IR, and TGA measurements. To disclose the adsorption properties of the composites, anionic compound acid red 18 (AR18) was selected as model adsorbate. The effects of pH, ionic strength, contact time, adsorption temperature, and initial concentration of AR18 on adsorption efficiency were investigated. It was found that pure SBA-15 had a negligible adsorption capacity while the CTS-functionalized composites showed large adsorption capacities (up to 232.6 mg g−1) with rapid adsorption kinetics (less than 120 min). It was also observed that the adsorption capacity increased with increase in CTS content of the composite. Results of comparative analysis indicated that SBA-15/CTS(20%) had better adsorption capacity than most of common adsorbents. Experimental kinetic and isotherm data were analyzed by theoretical models including pseudo-first-order and pseudo-second-order kinetics, Weber–Morris diffusion, Freundlich and Langmuir models. Moreover, adsorption thermodynamics has also been evaluated. The study suggests that the CTS-functionalized mesoporous composites are prospective adsorbents for adsorption of anionic compounds, and somewhat exemplifies their adsorbent function for adsorbing some other adsorbates.Graphical abstract

A new strategy to retrieve chitosan-decorated carbon nanotube (CS/CNT) from aqueous dispersion was proposed. The CS/CNT, prepared via a “surface deposition–crosslinking” method, exhibited an aggregation microstructure with plentiful interstitial spaces. By introducing magnetic nanoparticle (MNP) into CS/CNT dispersion solution, MNP was embedded in the CS/CNT aggregates, which endowed the CS/CNT with magnetic retrievability. Using this strategy, a simple and convenient operation for the removal of anionic azo dye (acid red 18 (AR18)) was achieved by directly adding CS/CNT and MNP into the dye solution, where CS/CNT acted as an adsorbent and MNP enabled all CS/CNT aggregates to be magnetically retrievable. Effects of pH, ionic strength, contact time, temperature, and initial AR18 concentration on adsorption efficiency were investigated. Results showed that AR18 adsorption could achieve equilibrium quickly and the maximum adsorption capacity could be up to 809.9 mg·g–1 at 323.15 K. Full kinetic and thermodynamic investigations as well as isotherm analysis were also undertaken. Moreover, the reusability of magnetically retrievable CS/CNT was evaluated, and the result showed that the removal of AR18 was kept relatively constant (99.11 % to 99.76 %) in 10 consecutive cycles. The study suggests that the magnetically retrievable CS/CNT is a promising adsorbent for removal of anionic azo dyes from aqueous solution.

•Magnetic mesoporous titania composite was facilely prepared by an anchoring method.•The anchoring method is simple and efficient.•The composite is effective and efficient for the enrichment of phosphopeptides.In this paper, a novel magnetic mesoporous titania composite (MNPs/mTiO2) was facilely prepared by anchoring magnetic nanoparticles (MNPs) onto the external surface of mesoporous titania (mTiO2) åsub-microparticles with the use of ethylenebis(nitrilodimethylene)tetraphosphonic acid (EDTMPA) as “bridge” molecule. The usefulness of MNPs/mTiO2 as adsorbent for the selective isolation and enrichment of phosphopeptides with subsequent analysis by matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS) was studied. The results showed that the MNPs/mTiO2 composite could be used in the highly efficient and rapid enrichment of phosphopeptides.

•AuNPs/uTiO2 was prepared via photoreduction deposition of Au nanoparticles (AuNPs) on urchin-like TiO2 nanosphere (uTiO2).•AuNPs/uTiO2 showed high surface area (147.5 m2 ⋅ g-1), large pore volume (0.52 cm3 ⋅ g-1), and high dispersity of AuNPs.•uTiO2 support could prevent leaching or aggregation of AuNPs, while allowing guest molecules to diffuse in and out easily.•AuNPs/uTiO2 exhibited superior catalytic efficiencies for dyes degradation and 4-nitrophenol reduction.•Catalytic activity of AuNPs/uTiO2 could remain almost unchanged after being recycled for several times.The development of efficient heterogeneous catalysts for degrading organic pollutants or converting them into harmless and even useful products is of vital significance for environmental remediation. Herein, we reported the facile synthesis of a highly active and stable nanocatalyst (AuNPs/uTiO2) via a simple photoreduction deposition of Au nanoparticles (AuNPs) on urchin-like TiO2 nanosphere (uTiO2), and demonstrated its excellent performances as a catalyst for oxidative degradation of organic dyes and reductive conversion of 4-nitrophenol (4-NP). The AuNPs/uTiO2 nanocomposite showed high surface area (147.5 m2·g− 1), large pore volume (0.52 cm3·g− 1), and high dispersity of AuNPs. In particular, the uTiO2 support could combine AuNPs strongly and serve as a shield to prevent leaching or aggregation of AuNPs, while allowing guest organic molecules to diffuse in and out easily. Benefiting from the excellent characteristics, the AuNPs/uTiO2 exhibited superior catalytic properties for dyes degradation and 4-NP reduction with significantly higher catalytic efficiencies than many previously reported heterogeneous catalysts. Moreover, the catalytic activity of AuNPs/uTiO2 could remain almost unchanged after being recycled for several times, demonstrating its long-term stability. The AuNPs/uTiO2, combining the advantages of high activity, favorable kinetics, and excellent durability for dye degradation and 4-NP reduction, should be very promising for wastewater treatment.Download high-res image (137KB)Download full-size image

•Hollow mesoporous silica spheres (HMSS) were facilely decorated by MnSiO3.•Such decoration method is simple, efficient, and scalable.•The resulting product well preserved morphological and textural features of HMSS.•The product showed excellent performance in both catalysis and adsorption.In this work, the MnSiO3 decorated hollow mesoporous silica spheres (MHMSS) was facilely synthesized via an one-step thermal treatment of hollow mesoporous silica spheres (HMSS) and MnCl2⋅4H2O in a binary solvents (ethylenediamine/ethylene glycol). Intriguingly, it was found that MnSiO3 nanocrystals were formed effectively on the pore surface of HMSS without pore blocking, and the resultant MHMSS fully inherited the morphological and textural characteristics of HMSS such as spherical hollow structure with mesoporous shell, large pore size (mainly distributed around 15.5 nm), high surface area (501.5 m2 g−1), and large pore volume (1.85 cm3 g−1). More importantly, the MHMSS exhibited high catalytic activities for oxidative degradation of methylene blue (MB), basic red 5 (BR), and rhodamine B (RhB) in the presence of H2O2. Typically, 10 mL of MB (50 mg L−1) can be decolored by 80% in 1 min and nearly 93% in 10 min. Moreover, the MHMSS also showed excellent adsorption properties in term of capacity and kinetics on removal of Pb2+. The Pb2+ adsorption could reach equilibrium within 100 min, and the maximum adsorption amount was up to 279.4 mg g−1 at 313.15 K, significantly higher than those found for many other adsorbents. The present results suggest that the MHMSS hybrid material can not only be used as a superior heterogeneous catalyst for degradation of organic contaminants, but also act as a highly efficient adsorbent for adsorptive removal of heavy metal ions, which may provide insight into the design and development of high-efficiency nanomaterials and nanotechnologies for environmental remediation.