•The composite PU foam was synthesized by a facile one-step foaming technology.•Hierarchical hollow SiO2@MnO2 cubes enhanced adsorption capacity of foam.•The composite PU foam selectively adsorb and continuously remove water from oil.•The composite PU foam showed excellent elasticity and recyclability.•The composite PU foam could be reused for at least ten cycles.Oil-polluted water has become a worldwide problem due to ever-increasing industrial oily wastewater as well as the frequent oil spill accident. A superior oil adsorbing material capable of separating oil–water mixtures efficiently, especially with a high oil adsorption capacity and mechanical strength, is urgently desired. Here, we report a novel strategy of preparing composite foams with hierarchical porous structures for effective oil/water separation and selective oil adsorption. The composite polyurethane foam is synthetized by a facile one-step foaming technology, which uses hierarchical hollow SiO2@MnO2 cubes to modify the inner structures of composite polyurethane foam. The incorporation of hierarchical hollow SiO2@MnO2 cubes into the foam could not only improve the morphologies, specific surface areas and hydrophobic properties but also enhance the adsorption capacity and mechanical properties. The as-prepared composite PU foam is put into the oil/water mixture to adsorb oils, and the adsorbed oils can be recovered simply by squeezing oil from composite PU foam. The resulting composite PU foam exhibits high oil adsorption capacity, high selectivity and oil adsorption capacity for carbon tetrachloride was measured to be 31.6 g/g. Also, the composite PU foam shows excellent elasticity and the height of the composite PU foam decreased from 100% to 94% after 30 compressing–releasing cycles. Furthermore, the as-prepared composite PU foam exhibits the high reusability and durability by being reused for oil–water separation for 10 cycles without losing its hydrophobicity, which makes it a good candidate for industrial oil-polluted water treatments and oil spill cleanup.Download high-res image (84KB)Download full-size image

•A new strategy named as post functionalization with B-N coordination complex was presented.•PGM-Pickering-0.10-BN possessed hierarchical porous structure and Wulff-type boronic acids.•PGM-Pickering-0.10-BN showed specific capture of flavone under neutral condition.•The results could be facilely adopted to predict and design optimal conditions in the scale-up.An apparent disadvantage of boronate affinity is that it has to be performed in alkaline media and can lead to the oxidation of cis-diols in compounds. A new strategy named as post functionalization with B-N coordination complex was present to prepare boronic acid suspended macroporous polymeric monolith for the selective capture of cis-diol-containing luteolin (LTL) under neutral condition. In this work, a water-in-oil (W/O) Pickering (high internal phase emulsions) HIPE template stabilized by boronic acid suspended mesoporous silica nanoparticles (BA-MSNs) was applied to prepare macroporous poly(glycidyl methacrylate) monolith (PGM-Pickering-0.10), and then B-N coordination complex resulted from the reaction of 3-aminophenylboronic acid (APBA) and 1,6-hexamethylenediamine was integrated to the PGM-Pickering-0.10. As-prepared hierarchical porous PGM-Pickering-0.10-BN with “Wulff-type boronic acids” possessed special mesopore-in-macropore structure. In static adsorption, pH-dependent adsorption experiments demonstrated that PGM-Pickering-0.10-BN was able to capture LTL with expected high adsorption amount (158.5 µmol g−1 at 298 K) and fast binding kinetics (equilibrium in 2.0 h) under neutral condition, while macroporous polymers without post functionalization or functionalized only with APBA display poor adsorption performance at pH = 7.0. In addition, BA-MSNs as the stabilizers enhanced the mechanical property and specific adsorption ability of PGM-Pickering-0.10-BN simultaneously, and the integrated B-N coordination complex did play vital roles in the specific adsorption of LTL. By optimizing dynamic adsorption factors with response surface methodology (RSM), the maximum adsorption amount of 177.8 µmol g−1 was also achieved under neutral condition.

•Hierarchical flower-like hollow structure Ag2WO4/WO3 photocatalysts were prepared.•Photocatalytic activity of sample was improved due to the formation of heterojunction.•Ag2WO4/WO3 has a larger reaction rate which is 17.0 and 7.5 times higher than those of WO3 and Ag2WO4.•The photocatalyst showed good stability for dye degradation.A series of hierarchical flower-like hollow structure Ag2WO4/WO3 photocatalysts was synthesized and characterized by XRD, SEM, Raman spectroscopy, XPS, photoluminescence (PL) spectra, and BET. The obtained results indicated the growth of finely distribution of Ag2WO4 on the surface of the WO3 hollow sphere. UV–vis diffuse reflectance spectroscopy (DRS) was used to investigate the absorption range and band gap of photocatalysts. The photocatalytic activities of the photocatalysts were evaluated by the decolorization of Rhodamine B (RhB) under visible-light irradiation. The results showed that the highest activity could be reached up to 94%. It was also found that the heterojunction structure photocatalyst exhibited excellent stability. The kinetic reaction rate of heterojunction structure photocatalyst was nearly 17.0 and 7.5 times higher than those of pure WO3 and Ag2WO4. A possible photocatalytic mechanism for decolorization of Rhodamine B was proposed.Download high-res image (61KB)Download full-size image

A highly fluorescent carbon dots were prepared by a facile one-pot hydrothermal method using degrease cotton (human waste) as the carbon source. The structure and morphology of prepared C-dots were characterized by fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The as-prepared C-dots exhibit excellent emission property, high stability and have a narrow size distribution of 2–4 nm in diameter. Moreover, it is attractive that C-dots can be used as an effective fluorescent probe for the detection of chromium ions with good selectivity and sensitivity in an aqueous solution. The quenching phenomenon was observed after the C-dots interacted with the metal ions; and the results showed that the optimum conditions for its interaction with chromium ions were: 4.0×10−5 g/mL of concentration of C-dots, pH=6.5 of buffer solution, and 20 min of time. Based on the optimum conditions, a new sensitive method detecting chromium ions was established. The method has been successfully applied to detect chromium ions in water and soil samples with satisfactory results.Download high-res image (237KB)Download full-size image

A novel β-cyclodextrin–carboxymethyl cellulose–graphene oxide composite material (β-CD–CMC–GO) was synthesized, and its application as excellent adsorbents was carried out for removal basic fuchsin (BF) in aqueous solution. The structure and morphology of β-CD–CMC–GO composite material were characterized by using FTIR, SEM, TEM, XRD, TG and DSC methods. The composites could remove basic fuchsin from aqueous solution efficiently. The adsorption experiment was carried out and the optimum experimental conditions were ascertained. The highest adsorption efficiency was obtained 97.3% at 0.015 g/mL dosage of β-CD–CMC–GO, the temperature of 25 °C and time of 2.5 h. Adsorption kinetics, adsorption isotherm and adsorption thermodynamic were used to analyze the adsorption system. The experimental data of adsorption kinetics of system were well followed by pseudo-second-order equation. The adsorption isotherm data were fitted using Langmuir isotherm model and Freundlich isotherm model. The maximum adsorption capacity of basic fuchsin reached 58.65 mg/g. The thermodynamic parameters indicated that the adsorption process was spontaneous and exothermic. The adsorbent has excellent regeneration ability and reproducibility. The proposed method shows that the β-CD–CMC–GO could be applied to removal of basic fuchsin in wastewater with satisfactory result.

•A novel fluorescent probe material (FCDs-IPDI-CD) was prepared.•The structure and morphology of FCDs-IPDI-CD were characterized.•FCDs-IPDI-CD could be quenched by Cr(VI) ions.•The proposed method was applied to detect Cr(VI) ions with satisfactory results.A water-soluble fluorescent carbon dots (FCDs) from cellulose was prepared using one-pot simple hydrothermal method. In this work, a novel fluorescent probe material, fluorescent carbon dots-linked isophorone diisocyanate and β-cyclodextrin (FCDs-IPDI-CD), was prepared with FCDs, isophorone diisocyanate (IPDI) and β-cyclodextrin (β-CD) as raw materials. The structure and morphology of FCDs-IPDI-CD were characterized using the Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The as-prepared FCDs-IPDI-CD exhibits excellent emission property and high stability. The fluorescence of the FCDs-IPDI-CD could be quenched by Cr(VI) ions, and the results indicate that FCDs-IPDI-CD can be used as an effective fluorescent probe for the detection of Cr(VI) ions with good selectivity and sensitivity in an aqueous solution. The influences of environment factors (such as pH, reaction time) on relative fluorescence intensity were studied. According to the optimum conditions, a new sensitive method detecting Cr(VI) ions was established. The method has been successfully applied to detect Cr(VI) ions in water and soil samples with satisfactory results.Download high-res image (122KB)Download full-size image

•Glucose functionalized multi-wall carbon nanotubes adsorbent (MWCNT/Gl) was prepared.•MWCNT/Gl has desirable adsorption efficiency (99.8%) for cationic dye RhB.•The adsorption kinetic and isotherm models were investigated.Glucose functionalized multi-wall carbon nanotubes (MWCNT/Gl) composites adsorbent was prepared. Adsorption characteristic of MWCNT/Gl was applied to deal with wastewater solution containing rhodamine B (RhB), methylene blue (MB), methyl orange (MO), malachite green (MG) and congo red (CR). The effects of adsorbent dosage, dye species, pH and contact time were conducted, and the adsorption kinetic and isotherm of adsorption process were investigated. The results indicate that MWCNT/Gl has desirable adsorption efficiency for cationic dyes. Especially for RhB, the adsorption efficiency achieves 99.8%. Kinetic data was well fitted by pseudo second-order model, and the equilibrium data were fitted by Langmuir isotherm model.

•W-doped porous g-C3N4 photocatalysts (W/PGCN) are prepared.•W-doped promotes the separation of the photo-generated electrons and holes.•Addition of appropriate H2O2 amount is beneficial for the photocatalytic activity.W-doped porous g-C3N4 photocatalyst was prepared by a hydrothermal method and characterized by XRD, SEM, BET and XPS. Enhancement of degradation efficiency of methyl orange (MO) by H2O2 addition was evaluated. The degradation efficiency achieves 99.6% within 60 min under visible light. Based on first-order model, the rate constant (k) of the prepared composite is up to 3.12 times as high as that of porous g-C3N4. W-doped not only narrowed the band gap, but also promoted the separation of the photo-generated electrons and holes. The prepared photocatalyst has potential application for the wastewater treatment containing MO dye.

•Ag–AgBr/TiO2–graphene (AATG) composite photocatalyst was prepared.•AATG was applied to photocatalytic degradation of polyacrylamide (PAM).•Degradation condition such as mass ratio of TiO2/graphene, dose, pH and time, was investigated.•The AATG composite photocatalyst can be separated from system effectively and easily.•The prepared AATG exhibits significant photocatalytic activity after five successive recycles.In current work, TiO2 was modified by Ag/AgBr semiconductor and graphene to enhance its photocatalytic activity for the degradation of polyacrylamide (PAM). Ag–AgBr/TiO2–graphene (AATG) composite photocatalysts were prepared by the deposition–precipitation method combining a subsequent calcination process. The structure, surface morphology and chemical composition of AATG composite photocatalysts were investigated by XRD, XPS, DRS, PL, SEM, EDS, TEM, and HRTEM methods. XRD and XPS results show that Ag0 is generated from Ag+ under visible light irradiation. Degradation of PAM was chosen to evaluate photocatalytic activity using AATG composite as photocatalysts. The conditions such as mass ratio of TiO2/graphene, catalyst dose, pH and contact time, were investigated for the degradation of PAM. Possible pathway and mechanism were proposed for photocatalytic degradation of PAM over AATG composite photocatalyst under visible light irradiation. The prepared AATG composite photocatalyst can be separated from system effectively and easily; and exhibits significant photocatalytic activity after five successive recycles, which confirmed that the components of the AATG are not photo decomposed and the structure is stable during the photocatalytic process.

•NiO/GO nanocomposite could be prepared via a hydrothermal method.•Removal of MB using adsorption and photodegradation activity was investigated.•A remarkable 97.54% of MB was achieved by coupled photodegradation and adsorption.Nickel oxide/graphene oxide (NiO/GO) nanocomposite was prepared by a hydrothermal method combining a subsequent calcination process. X-ray diffraction (XRD), Raman spectrometer (Raman), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and X-ray photoelectron spectroscopy (XPS) methods were used for the characterization of nanocomposite. Removal of aromatic heterocyclic dye methylene blue (MB) from aqueous solution using adsorption and photodegradation activity of NiO/GO nanocomposite was investigated. The effects of NiO/GO nanocomposite dose, pH, and contact time on the removal efficiency of MB were also investigated. Compared with that in the dark, NiO/GO nanocomposite shows a faster and higher removal efficiency by the photodegradation and adsorption under visible light irradiation. A remarkable removal efficiency of MB achieved 97.54% by NiO/GO nanocomposite after 2 h. It could be concluded that synergy of photodegradation and adsorption has a significant progress for removal of MB under visible light compared with that of only adsorption without light.

A coupled system for the photodegradation of Rhodamine B dye was realized using a Bi2S3/g-C3N4 composite as a photocatalyst under visible light irradiation. The Bi2S3/g-C3N4 composite was prepared by a hydrothermal method and characterized by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Compared with pure g-C3N4, the Bi2S3/g-C3N4 sample exhibits an enhanced photocatalytic activity and the best photocatalytic efficiency is 3.68 times more than that of pure g-C3N4. The obtained results indicate that a coupled system of Bi2S3 and g-C3N4 could overcome the drawback of low photocatalytic efficiency brought by electron–hole recombination and a narrow photoresponse range. On the basis of the corresponding energy band positions, the mechanism of photocatalytic activity enhancement was proposed.

•Al-Ca hydrotalcite/K2CO3 was prepared as a solid base catalyst.•The catalyst can be applied to the transesterification under mild conditions.•The catalyst shows high activity and can be easily recovered and regenerated.A novel heterogeneous solid base catalyst was prepared with the support of Al-Ca hydrotalcite, the load of K2CO3 and successfully applied to the transesterification of soybean oil with methanol to biodiesel (fatty acid methyl esters). The prepared catalysts were characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectrometer, transmission electron microscopy, thermogravimetry analysis, differential scanning calorimetry and the Hammett indicator methods. The results indicated that K2CO3 loaded to Al-Ca hydrotalcite was decomposed into catalytic active compositions of K2O and Al–O–K. The effect of various parameters such as reaction temperature, amount of catalyst, reaction time and the amount of methanol on the catalytic active was investigated. The optimal reaction conditions were obtained by this experiment: a methanol/oil mole ratio of 13:1, a reaction temperature of 65 °C, a catalyst amount of 2.0 wt.% and a reaction time of 2.0 h. The catalyst has longer lifetime and biodiesel yield could be still over 87.4% after being used for four cycles.

•Azo benzothiazole polyurethane-urea (BTPUU) was synthesized and characterized.•The physical and optical properties of BTPUU film were investigated.•Y-branch and MZI waveguide thermo-optic switch were proposed and simulated.•Power consumption and response time were obtained.•The studies revealed that the BTPUU can be a potent candidate thermo-optic switch.A chromophore molecule 4-[(benzothiazole-2-yl)diazenyl]phenyl-1,3-diamine (BTPD) was prepared with 2-amino benzothiazole and m-phenylenediamine by diazo-coupling reaction. Then, the BTPD was polymerized with polyether polyol (NJ-220) and isophorone diisocyanate (IPDI) to obtain novel azo benzothiazole polyurethane-urea (BTPUU). The chemical structures of BTPD and BTPUU were characterized by FT-IR and UV–visible spectroscopy. The thermal and mechanical properties of BTPUU film were investigated. The refractive index and transmission loss of BTPUU film were measured at different temperatures and different laser wavelengths (532 nm, 650 nm and 850 nm) by an attenuated total reflection (ATR) technique and CCD digital imaging devices. The thermo-optic coefficients of BTPUU are −4.7086 × 10−4 °C−1 (532 nm), −6.5257 × 10−4 °C−1 (650 nm) and −5.1029 × 10−4 °C−1 (850 nm), respectively. A Y-branch switch and Mach–Zehnder interferometer (MZI) thermo-optic switches based on thermo-optic effect were proposed and the performances of the switches were simulated, respectively. The results show that the power consumption of the Y-branch thermo-optic switch is only 3.28 mW. The response times of Y-branch and MZI switches are 8.0 ms and 2.0 ms, respectively. The results indicate that the prepared BTPUU has high potential for the applications of the Y-branch digital optical switch (DOS), MZI thermo-optic switch, directional coupler (DC) switch and optical modulators.