In this work, we successfully prepared the mussel-inspired polydopamine microspheres (PDA-Ms) with controllable sizes, through a facile self-oxidative polymerization method. The prepared PDA-M biomaterial with environmentally benign properties exhibits efficient lead(II) sequestration against high salts of competitive Ca(II), Mg(II), or Na(I) ions. It reveals 30 times greater than the commercial ion-exchanger 001x7 by selectivity evaluation. Kinetic results show that an exceedingly rapid lead(II) uptake can be achieved below 1 min. More attractively, the prepared PDA-Ms further exhibit the distinguished application ability with superior treated capacity of ∼42000 kg contaminated water/kg sorbent, and the effluents can be reduced from 1000 μg/L to below 10 μg/L, reaching the drinking water standard (WHO), which is equal to 200 times greater than commercial ion exchanger resin (∼210 kg) and granular activated carbon (∼120 kg). In addition, the exhaust PDA-M material can be well regenerated and repeated use using binary 1% HCl + 5% Ca(NO3)2 solution. X-ray photoelectron spectroscopy (XPS), zeta potential, and FT-IR analysis prove that such satisfactory performances can be ascribed to the following aspects (1) the well-dispersed nanoscale morphology and highly charged property will achieve the rapid adsorption and sufficient sorbent utilization. That is, the negatively-charged PDA sphere can exert the famous Donnan membrane effects for target lead(II) enrichment and diffusion enhancement; (2) the strong amine and carbonyl/hydroxyl group within the matrix can offer sorption selectivity for powerful lead(II) capture. Effective performances as well as environmentally friendly features suggest PDA-M material is a promising lead(II)-removing candidate for water remediation.Keywords: Adsorption; Application; Heavy metal; Polydopamine;

•GO composite hydrogels via thiol-ene photopolymerization.•Hydrogels prepared in an eco-friendly and effective manner.•Hydrogels exhibit good removal rates for model dyes.•Significant potentials towards wastewater treatment.The design and self-assembly of graphene oxide (GO)-based hierarchical composite gels have attracting numerous attentions due to wide applications in nanomaterial and environmental fields. In this research work, a facile strategy is demonstrated to prepare chemically modified graphene oxide-poly(ethylene glycol) diacrylate (GO-PEG) composite hydrogels by thiol-ene photopolymerization. The photopolymerization process between thiol groups on GO surface and ene segments in soluble PEG derivatives is critically predominant for the formation of composite hydrogels. The obtained composite hydrogels show good removal capacities and fit in pseudo-second-order model for used three model dyes. Thus, the present obtained GO-PEG composite hydrogels constructed by thiol-ene photopolymerization via eco-friendly prepared manner demonstrate new clues for preparing GO-based composite hydrogels and soft matter towards wastewater treatment applications.Download high-res image (186KB)Download full-size image

The design and preparation of functional beta-cyclodextrin-based composite films are of key importance for wide application fields. This study demonstrates a new route to construct composite films by Langmuir-Blodgett (LB) method via cholesterol-modified beta-cyclodextrin derivative (CD-CHOL). The inclusion complex formation of CD-CHOL and azobenzene derivative (N-Azo) at the air/water interface was investigated. It has been found that the interfacial host-guest recognition could easily occur in the in situ formed CD-CHOL/N-Azo composite films and relatively difficult to occur in the ex situ immersed composite films, because there exist host-guest interaction as well as intermolecular hydrogen bonding interaction. The inclusion complex formation was confirmed by changes in the surface pressure-area isotherms, circular dichroism (CD) and UV–vis spectra of the transferred LB films. And the solvent effect of the composite CD-CHOL/N-Azo films was also investigated, indicating that host-guest interaction between N-Azo and CD-CHOL could occur rather in the nonpolar solvent than the polar solvent. The present research work about beta-cyclodextrin-based composite films by LB method may provide new exploration to prepare organized composite films and demonstrate potential applications in many fields.Download high-res image (171KB)Download full-size image

•Develop new GO-dye composite Langmuir films.•Prepare highly ordered nanostructures.•Controllable H-aggregates and/or J-aggregates.•Significant potentials in soft matter and graphene film.Graphene oxide (GO)-based nanocomposite films via facile and appropriate self-assembly methods have demonstrated many potential applications in wide fields. This study demonstrates a facile and clean route to prepare graphene oxide-dye composite films using Langmuir-Blodgett (LB) technique at room temperature. By electrostatic interaction between cationic dye molecules and negatively charged GO sheets as well as π-π interactions, GO-dye composite LB films were formed spontaneously. As a soft platform for dye molecules, GO sheets induce dye molecules to self-assemble and form highly ordered structures containing H-aggregates and/or J-aggregates. The morphological characterization results show the formation of GO-dye composite films with smooth and dense surfaces. And the spectral results reveal that dye molecules stack in well-organized aggregates on the surface of GO sheets corresponding to monomers in bulk solution. The present research work about GO-dye composite films by LB method may provide new clues to prepare organized composite films and demonstrate potential applications in many fields.Download high-res image (149KB)Download full-size image

•We develop the new applicability of ZrP towards F in waters.•ZrP exhibits a good chemical stability against acid or base environments.•Superior capacity can be attached with 3900 Kg acidic wastewaters/Kg ZrP.•Its capability exceeds the commercial D201, AA, GFH, Manganese and Magnetite.•Fast Fluoride uptake can be achieve in below 5 min.Zirconium phosphate (ZrP) has been developed as an efficient adsorbent, since the 1960s, but most research involving ZrP focuses on metal cation (e.g. K+/Ca2+/Pb2+/Cu2+) capture. Herein, we synthesized a ZrP nanoflake by simple in-situ precipitation procedures and successfully explored a new application area for it: fluoride scavenging. Completely different from the conventional metal oxides, the resultant ZrP exhibits good chemical stability in acidic or basic environments. More importantly, preferable fluoride uptake can be achieved at high concentrations of competitive anions (SO42−/Cl−/NO3−) addition, exceeding that of commercial D201, activated Al2O3, manganese sands, etc. Kinetic results further demonstrate its efficiency for approaching equilibrium in 5 min. Furthermore, the actual application proves superior treatment capacities of approximately 1800 kg and 3900 kg for groundwater and acidic wastewater treatment, respectively and the exhausted materials can be readily regenerated using 5% NaOH solution for at least five cycles. XPS and FT-IR investigation reveal that the preferable fluoride adsorption can be ascribed to strong inner-sphere complexation achieved by ZrF bonds. All the results demonstrate that the representative ZrP nanoflake is an efficient and rapid fluoride-removing candidate for cleaning water.Download high-res image (271KB)Download full-size image

•AuNPs-modified diamond-based nanocomposite catalysts.•Provide excellent catalytic performance of 4-nitrophenol.•The composite catalyst demonstrates good stability and reusability.The diamond-based hierarchical AuNPs-modified nanocomposites materials were prepared via the synthesis of diamond@graphite building block and polyallylamine hydrochloride (PAH)/polyacrylic acid (PAA) layer-by-layer (LbL) assembled strategy. And the modified gold nanoparticles were carried out by the reduction of aqueous HAuCl4 solution using the reductant NaBH4. The obtained layer-by-layer nanocomposites demonstrate obvious advantages such as high specific surface area, pore diameter and pore volume, providing a higher chance of gold nanoparticles accessible to the reactants. Thus the core–shell nanostructures from of LbL-assembled and diamond-based composite materials are beneficial to improve the catalytic capacity of gold nanoparticles and separation rate from the reactants. In order to testify the enhancement of hierarchical diamond-based AuNPs-modified nanocomposites catalytic activity and utility, the catalytic experiments of 4-nitrophenol solution were well accomplished. The prepared nanocomposites exhibited high activity and demonstrated high recyclability without less weight of gold nanoparticles after eight runs of catalysis reduction of 4-nitrophenolm showing potential application in composite catalytic materials.Download high-res image (164KB)Download full-size image

•TiO2 nanoparticles modified electrospun nanocomposite catalysts.•TiO2 nanoparticles provide excellent photocatalytic activity.•The analysts demonstrate good stability and reusability.New poly(vinyl alcohol)/poly(acrylic acid)/carboxyl-functionalized graphene oxide nanocomposite membranes were prepared using electrospinning technique with thermal treatment and modified with TiO2 nanoparticles. The thus prepared composite membranes are composed of polymeric nanofibers with carboxyl-functionalized graphene oxide sheets, which are anchored on the fibers by heat-induced crosslinking reaction. The preparation process of the designed nanocomposites is facile, eco-friendly, and controllable. The TiO2 nanoparticles were deposited uniformly and homogeneously onto the surface of the obtained composite membranes. The as-prepared composite membranes demonstrate efficient photocatalytic capacity toward dye degradation, which is primarily due to the specific surface area of electrospun membranes and the photoactivity of TiO2 nanoparticles. In addition, the composite membranes reported here are easy to regenerate. In comparison with other composite catalysts, the present preparation process is highly eco-friendly and facile to operate and regulate, which demonstrates potential large-scale applications in wastewater treatment and dye removal.Download high-res image (137KB)Download full-size image

AbstractThe design and fabrication of quantum dots (QDs) with circularly polarized luminescence (CPL) has been a great challenge in developing chiroptical materials. We herein propose an alternative to the use of chiral capping reagents on QDs for the fabrication of CPL-active QDs that is based on the supramolecular self-assembly of achiral QDs with chiral gelators. Full-color-tunable CPL-active QDs were obtained by simple mixing or gelation of a chiral gelator and achiral 3-mercaptopropionic acid capped QDs. In addition, the handedness of the CPL can be controlled by the supramolecular chirality of the gels. Moreover, QDs with circularly polarized white light emission were fabricated for the first time by tuning the blending ratio of colorful QDs in the gel. The chirality transfer in the co-assembly of the achiral QDs with the gelator and the spacer effect of the capping reagents on the QD surface are also discussed. This work provides new insight into the design of functional chiroptical materials.

AbstractThe design and fabrication of quantum dots (QDs) with circularly polarized luminescence (CPL) has been a great challenge in developing chiroptical materials. We herein propose an alternative to the use of chiral capping reagents on QDs for the fabrication of CPL-active QDs that is based on the supramolecular self-assembly of achiral QDs with chiral gelators. Full-color-tunable CPL-active QDs were obtained by simple mixing or gelation of a chiral gelator and achiral 3-mercaptopropionic acid capped QDs. In addition, the handedness of the CPL can be controlled by the supramolecular chirality of the gels. Moreover, QDs with circularly polarized white light emission were fabricated for the first time by tuning the blending ratio of colorful QDs in the gel. The chirality transfer in the co-assembly of the achiral QDs with the gelator and the spacer effect of the capping reagents on the QD surface are also discussed. This work provides new insight into the design of functional chiroptical materials.

There are tremendous challenges from both tumor and its therapeutic formulations affecting the effective treatment of tumor, including tumor recurrence, and complex multistep preparations of formulation. To address these issues, herein a simple and green approach based on the self-assembly of therapeutic agents including a photosensitizer (chlorine e6, Ce6) and a chemotherapeutic agent (doxorubicin, DOX) was developed to prepare carrier-free nanoparticles (NPs) with the ability to inhibit tumor recurrence. The designed NPs were formed by self-assembly of Ce6 and DOX associated with electrostatic, π–π stacking and hydrophobic interactions. They have a relatively uniform size of average 70 nm, surface charge of −20 mV and high drug encapsulation efficiency, which benefits the favorable accumulation of drugs at the tumor region through a potential enhanced permeability and retention (EPR) effect as compared to their counterpart of free Ce6 solution. In addition, they could eradiate tumors without recurrence in a synergistic way following one treatment cycle. Furthermore, the NPs are safe without any activation of inflammation or immune response in separated organs. Taken together, the rationale of these pure nanodrugs via the self-assembly approach might open an alternative avenue and give inspiration to fabricate new carrier-free nanodrugs for tumor theranostics, especially for two small molecular antitumor drugs with the aim of combinational antitumor therapy in a synergistic way.

Self-assembling peptide-based materials are playing an important role in fabricating drug delivery carriers; however, they are often limited by several challenges, such as precise structure modulation, desirable nanoscale size, and sufficient circulation lifetime in the body. To address this issue, herein one type of injectable dipeptide-based nanocarriers with well-modulated size and structure has been developed by adjusting glutaraldehyde (GA)-assisted cationic dipeptide (CDP) assembly. After loading a model photosensitive drug (Ce6) and further decorating CDP nanoparticles (NPs) with heparin polymers (Hep), the desired dipeptide-based NPs are achieved with an average diameter of 100 nm and surface charge of −25 mV, which are favorable for the enhanced permeability and retention effects. Significantly, the dipeptide-based NPs with Ce6 loading have a longer circulation lifetime against opsonization than free Ce6 solution, and subsequently, they achieve the best anticancer efficiency in vivo. They do not cause body weight loss or induce bad immune activation in organs, implying good biosafety of the designed carriers. Taken together, dipeptide-based delivery carriers through GA-assisted assembly may provide a new alternative for developing precisely controlled nanostructures toward effective antitumor therapy.Keywords: dipeptide; drug delivery; nanoparticle; photodynamic therapy; self-assembly

The biogenic synthesis of biomolecule–gold nanoconjugates is of key importance for a broad range of biomedical applications. In this work, a one-step, green, and condition-gentle strategy is presented to synthesize stable colloidal gold–collagen core–shell nanoconjugates in an aqueous solution at room temperature, without use of any reducing agents and stabilizing agents. It is discovered that electrostatic binding between gold ions and collagen proteins and concomitant in situ reduction by hydroxyproline residues are critically responsible for the formation of the core–shell nanoconjugates. The film formed by layer-by-layer assembly of such colloidal gold–collagen nanoconjugates can notably improve the mechanical properties and promote cell adhesion, growth, and differentiation. Thus, the colloidal gold–collagen nanoconjugates synthesized by such a straightforward and clean manner, analogous to a biomineralization pathway, provide new alternatives for developing biologically based hybrid biomaterials toward a range of therapeutic and diagnostic applications.Keywords: cell adhesion and growth; collagen protein; colloidal gold nanoparticles; core−shell nanoconjugates; layer-by-layer assembly

In this study, the hydrogel materials of reduced graphene oxide (RGO)/chitosan/silver nanoparticle composites were designed and prepared via a self-assembly process and simultaneous reduction of chitosan molecules with GO. These as-prepared hydrogels were characterized by different techniques. The morphology of the internal network structure of the nanocomposite hydrogels was investigated. The catalytic capacity results demonstrate that the prepared GO-based composite hydrogels can efficiently remove two tested dye molecules from wastewater in good accordance with the pseudo-second-order model. The dye photocatalytic capacity of the obtained hydrogels is mainly attributed to the silver nanoparticle on RGO sheets, whereas the chitosan molecule was incorporated to facilitate the gelation process of the GO sheets. Interestingly, the as-prepared catalytic composite material serves as a good photocatalyst for two presently used dyes even for dye mixtures, suggesting the potentially real applications of the GO composite materials for wastewater treatment as well as the removal of harmful dyes.Keywords: Chitosan; Composite hydrogel; Dye degradation; Graphene oxide; Wastewater treatment

Artemia nauplii are important bait or food sources in aquaculture, but the egg shells after incubation are always subjected to discarding as natural wastes; therefore, application and utilization of the Artemia egg-shell wastes will be an important issue. Herein, we reported a new hybrid biomaterial by encapsulating nano-Mg(OH)2 onto discarded Artemia egg shells for phosphate sequestration enhancement. The unique hierarchically 3D-layered structure of Artemia egg shells can endow well-defined nano-Mg(OH)2 morphology and efficient phosphate adsorption performances. The results of the final hybrid biomaterial exhibit a wide pH dependent sorption process, strong affinity toward phosphate removal, and large sorption capacity. Moreover, the exhausted adsorbent shell–Mg-P can be further utilized as slow-release fertilizer without regular chemical regeneration. The efficient slow-release behaviors of phosphorus onto Shell–Mg–P for 30 days indicated the potential applicability as fertilizers. Additionally, the actual seedling tests further confirm that the shell–Mg–P can be readily used as a slow-release fertilizer for the soil improvement and crop productivity.Keywords: Artemia egg shell; Biomaterial; Plant grown; Waste;

Phosphate removal is important for the control of eutrophication, and adsorption may serve as a powerful supplement to biological phosphate sequestration. Here, we develop a new composite adsorbent (denoted as HMO-PN) by encapsulating active nano-Mg(OH)2 onto macroporous polystyrene beads modified with fixed quaternary ammonium groups [CH2N+(CH2)3Cl]. The N+-tailored groups can accelerate the diffusion of target phosphate through electrostatic attractions. The performance of the as-prepared HMO-PN was found to depend on the pH value of an aqueous medium. HMO-PN also exhibits high sorption selectivity toward the target phosphate. Kinetic equilibrium of phosphate adsorption can be achieved within 100 min, and the calculated maximum adsorption capacity is approximately 1.47 mmol/g (45.6 mg/g). Column experiments further show that the effluent concentration of phosphate can be reduced to below 0.5 mg/L (500 BV), suggesting highly efficient phosphate sequestration. Moreover, the exhausted HMO-PN can be readily regenerated using an alkaline brine solution.

Water pollution by heavy metals remains a serious environmental and health issue. Herein, a new hybrid adsorbent was prepared for selective Cd(II) sequestration by immobilizing nanosized zirconium hydroxides (HZO) onto a macroporous cation exchanger. The positively charged SO3−H group within the host matrix can accelerate the target Cd(II) ions diffusion and enrichment, combining with the strong adsorption by HZO nanoparticles. Solution pH influence proves that Cd(II) can be efficiently eliminated by HZO-PS in a wide pH range of 2.5–7.0 with negligible Zr(IV) releases. Both HZO-PS and PS exhibit similar and fast kinetic behaviors by approaching sorption equilibrium within 150 min. Such results can be ascribed to the unique surface-charged groups for accelerating Cd(II) diffusion. Moreover, HZO-PS also exhibits favorable sorption selectivity in the presence of common cations at high levels. Fixed-bed column experiments further demonstrate its efficient applicability with the treated capacity of 750 bed volume (BV) per run and the exhausted HZO-PS can be readily regenerated using binary HNO3 and Ca(NO3)2 mixtures for repeated use. All the results suggest that the hybrid material HZO-PS is a promising adsorbent for cadmium retention in water.

Phosphate is a worldwide environmental issue, due to possibly causing serious eutrophication and subsequently blue-green algae blooms. Sequestrating phosphate by exploitation of advanced materials with a hierarchical morphology will be an important pathway. Herein, we fabricated a new sea urchin-like zirconium(IV) oxide (Ur-Zr) using a one step facile alcoholysis solvothermal reaction for efficient phosphate removal. The as-obtained material exhibits adsorption properties in a wide range of pH conditions with the optimal pH ranging from 1.0 to 6.0; competition results reveal that the Ur-Zr displays remarkable sorption selectivity for phosphate removal with coexisting common anions (SO42−, NO3− and Cl− ions) at high concentrations, which can be ascribed to the unique hierarchical morphology and strong sorption affinity between Zr–O and phosphate species. Besides, the resultant Ur-Zr also shows a gradual sorption kinetics behavior, which can be well described by the pseudo-first-order model with the maximum sorption capacity of 74.8 mg g−1. Additionally, the exhausted materials can be recycled by alkaline treatment and used repeatedly. All of the results demonstrate that the sea urchin-like zirconium(IV) oxide is a competent candidate for enhanced phosphate removal.

Graphene oxide (GO)-chitosan composite hydrogels were successfully prepared via the self-assembly of chitosan molecules and GO. These as-prepared hydrogels were characterized by different techniques. The morphology of the internal network structure of the nanocomposite hydrogels was investigated. The adsorption capacity results demonstrate that the prepared GObased composite hydrogels can efficiently remove three tested dye molecules, Congo red, methylene blue and Rhodamine B, from wastewater in accordance with the pseudo-second-order model. The dye adsorption capacity of the obtained hydrogels is mainly attributed to the GO sheets, whereas the chitosan molecule was incorporated to facilitate the gelation process of the GO sheets. The present study indicates that the as-prepared composite hydrogels can serve as good adsorbents for wastewater treatment as well as the removal of harmful dyes.本文通过壳聚糖分子与氧化石墨烯(GO)的自组装成功制备了GO-壳聚糖复合水凝胶, 并对该水凝胶进行了表征. 研究发现复合水凝胶中存在网状微观结构. 吸附性能结果表明制得的基于GO的复合水凝胶可以有效地从废水中去除三种测试染料分子, 同时符合准二阶模型. 该水凝胶的染料吸附能力主要来源于GO片层, 而壳聚糖分子促进了GO片层的凝胶化过程. 目前的研究结果表明制备的复合水凝胶可以作为良好的吸附剂应用于废水处理以及有害染料去除等领域.

•New binary organogels in single or mixed solvents were prepared.•Various nanostructures and hydrogen bonds from different solvents were investigated.•Solvents and molecular skeletons are crucial to the gelation behaviors.•Suitable single/volume ratios in mixed solvents are favorable for gel formation.In this paper new binary organogels based on glutamic acid derivatives and acids with different molecular skeletons were designed and prepared. Their gelation behaviors in single or mixed solvents were tested as novel low-molecular-mass organic gelators. The experimental data showed that the solvents and molecular skeletons played a crucial role in regulating the gelation behaviors and fabrication of nanostructures. Suitable single solvents or volume ratios in ethanol/water mixed solvents seemed more favorable for the formation of supramolecular gels due to cooperation of multi-intermolecular weak forces. Rational assembly modes in organogels were proposed and discussed. The present work may give some insight to design and character new versatile organogelators and soft materials with special molecular structures.

Four achiral Cu(II)-coordinated Schiff bases complexes containing aromatic structures were synthesized and their supramolecular assemblies at the air/water interface were investigated. All the compounds could be spread on water surface although they have no alkyl chains. The Schiff base complex molecules with naphthyl groups tended to form J-aggregate in the Langmuir-Blodgett (LB) films transferred from water surface. By investigation of atomic force microscopy, a multilayer film or three-dimensional structures were observed. It was interesting to note that the LB films of achiral compound Cu-NA with naphthyl segment and without methyl groups transferred from water surface showed chirality. The supramolecular chirality in the present LB films was suggested to be due to a cooperative stereoregular π-π stacking of the functional groups in a helical sense. This research work provides a helpful clue for regulating the nanostructures and supramolecular chiral assembly in organized films.

Two new cholesterol imide derivatives with azobenzene substituent groups have been synthesized. The compounds possess headgroups of hydrogen or methyl units, respectively. The gelation test revealed that a subtle change in the headgroup of azobenzene segment produced a dramatic change in the gelation behavior of both compounds. The compound with headgroups of hydrogen units only gelated N,N-Dimethylformamide (DMF), while the other compound with headgroups of methyl units cannot gelate any solvent tested herein. For DMF gel and solution of the gelator, the reversible photoisomerization transitions by irradiation with ultraviolet (UV) and visible light are investigated by UV-vis absorption spectra, Fourier transform infrared spectrometer, scanning electron microscope, atomic force microscope, and X-ray diffraction analyses. Upon UV irradiation of the gel, trans–cis photoisomerization of the azobenzene groups occurs, the change in molecular polarity leads to the breaking of van der Waals interactions, resulting in the gel–sol transition. The gel can be recovered by the reverse cis–trans photoisomerization after exposure to visible light. Morphological and spectral studies reveal that the gelator molecules self-assemble into one-dimensional fibers, which further crossed-linked to form regular nanobelts. These results afford useful information for the development of new versatile low molecular mass gelators and soft matter.

A new series of trigonal Schiff base amphiphiles with symmetric aromatic cores and different substituted headgroups were designed and their interfacial assemblies were investigated. When on the metal ions subphases, an in situ coordination can occur for all compounds. The coordinated films could be transferred onto solid substrates and subsequently characterized by various spectroscopic methods such as UV–vis and Fourier infrared spectra as well as the morphological characterization with atomic force microscopy measurement. In addition, on acidic or alkaline subphases with different pH values, the interfacial behaviors and morphologies changed obviously due to the dissociation of the phenol group at alkaline subphase and protonation of the azomethine at strong acidic subphase. Depending on the trigonal molecular structures and different substituted headgroups, these amphiphiles showed distinct assembly behaviors in the organized molecular films. At the same time, a rational explanation about the influence of molecular structures and headgroups on regulating the assembly behaviors was proposed.Graphical abstractHighlights► Some trigonal amphiphiles with different substituted headgroups are synthesized. ► These amphiphiles showed obvious headgroup effect in the LB films. ► On acidic or alkaline subphases, the interfacial behaviors changed obviously.