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With the development and application of graphene oxides (GO), the potential toxicity and environmental behavior of GO has become one of the most forefront environmental problems. Herein, a novel nanoscale layered double hydroxides (glycerinum-modified nanocrystallined Mg/Al layered double hydroxides, LDH-Gl), layered double oxides (calcined LDH-Gl, LDO-Gl) and metallic oxide (TiO 2 ) were synthesized and applied as superior coagulants for the efficient removal of GO from aqueous solutions. Coagulation of GO as a function of coagulant contents, pH, ionic strength, GO contents, temperature and co-existing ions were studied and compared, and the results showed that the maximum coagulation capacities of GO were LDO-Gl (448.3 mg g −1 ) > TiO 2 (365.7 mg g −1 ) > LDH-Gl (339.1 mg g −1 ) at pH 5.5, which were significantly higher than those of bentonite, Al 2 O 3 , CaCl 2 or other natural materials due to their stronger reaction active and interfacial effect. The presence of SO 3 2− and HCO 3 − inhibited the coagulation of GO on LDH-Gl and LDO-Gl significantly, while other cations (K + , Mg 2+ , Ca 2+ , Ni 2+ , Al 3+ ) or anion (Cl − ) had slightly effect on GO coagulation. The interaction mechanism of GO coagulation on LDO-Gl and TiO 2 might due to the electrostatic interactions and strong surface complexation, while the main driving force of GO coagulation on LDH-Gl might be attributed to electrostatic interaction and hydrogen bond, which were further evidenced by TEM, SEM, FT-IR and XRD analysis. The results of natural environmental simulation showed that LDO-Gl, TiO 2 or other kinds of natural metallic oxides could be superior coagulants for the efficient elimination of GO or other toxic nanomaterials from aqueous solutions in real environmental pollution cleanup. [ABSTRACT FROM AUTHOR]

The effluent discharge containing chromium, which is toxic and potentially carcinogenic, will lead to serious environmental problems. The removal of chromium is usually carried out by ion exchange, precipitation, membrane filtration, adsorption, and photocatalytic reduction. This paper focuses on the adsorption method to remove chromium. For decades, the rapid development of adsorbent materials, including natural minerals, synthetic polymers, metal oxides, layered double hydroxides, mesoporous silica, carbon materials and porous framework materials, etc. In this review, we provide a systematic and comprehensive overview of the research on chromium removal by these emerging materials. The different determination methods of chromium and adsorption mechanisms, including macroscopic experiment methods, microscopic spectrum methods and calculation methods, are summarized in brief. Finally, we summarized the current problems according to the performance comparison of various adsorbents, and proposed the development direction of adsorbents used in the treatment of chromium containing wastewater in hopes of fueling more dramatic advancements in the material and environmental remediation fields. [Display omitted] • A systematic and comprehensive overview for chromium removal by these emerging materials. • The different determination methods of chromium and adsorption mechanism are briefly summarized. • Propose the development direction of adsorbents used in the treatment of chromium-contained wastewater. [ABSTRACT FROM AUTHOR]

In this work, cobalt/nickel-based metal-organic frameworks (Co/Ni-MOFs) modified bismuth oxyiodine (BiOI) composite (Co/Ni-MOFs@BiOI) was successfully prepared via a hydrothermal method and used as a novel light-driven photocatalyst for the degradation of cationic methylene blue (MB) in aqueous solutions under visible-light irradiation. It was found that Co/Ni-MOFs in combination with BiOI greatly improved the capability of absorbing visible light, resulting in boosting photocatalytic degradation of MB in aqueous solutions without any chemical additives. The photocatalytic activity of Co/Ni-MOFs@BiOI composites toward MB was enhanced significantly, almost 4 times higher than that of Co/Ni-MOFs, which could be attributed to the reduction of electron-hole pair recombination as well as synergetic effect. Moreover, the results of parallel experiments showed that Co/Ni-MOFs@BiOI composites could be used as a highly efficient photocatalyst to decompose other dyes including crystal violet (CV), rhodamine 6G (R6G), malachite green (MG), congo red (CR) and methyl orange (MO) under the visible light illumination. The trapping experimental results showed that superoxide radicals (· O 2 −) was the primary reactive species in the photodegradation reaction of MB, and a possible photodegradation mechanism of MB in the presence of Co/Ni-MOFs@BiOI was proposed. [Display omitted] • Co/Ni-MOFs@BiOI heterostructure was synthesized, characterized and applied. • BiOI enhanced the visible-light photocatalytic activity of Co/Ni-MOFs. • Superoxide radical (· O 2 −) was the primary reactive species in photodegradation. [ABSTRACT FROM AUTHOR]

The worldwide increase of AIDS, an epidemic infection in constant development has an essential and still requires potent antiretroviral chemotherapeutic agents for reducing the integer of deaths caused by HIV. Thus, there is an urgent need for new anti -HIV drug candidates with increased strength, new targets, superior pharmacokinetic properties, and compact side effects. From this viewpoint, we first review present strategies of anti -HIV drug innovation and the synthesis of heterocyclic or natural compound as anti -HIV agents for facilitating the development of more influential and successful anti -HIV agents. Image 1 • We have reported different classes of potent HIV inhibitors. • The development of new classes of anti -HIV drugs are still needed. • We have briefly explained the SAR of anti -HIV agents. [ABSTRACT FROM AUTHOR]

Peroxymonosulfate (PMS) based advanced oxidation processes have gained widespread attention in refractory antibiotics treatment. In this study, Fe 3 O 4 nanoparticles anchored nitrogen-doped porous carbon microspheres (Fe 3 O 4 /NCMS) were synthesized and applied to PMS heterogeneous activation for doxycycline hydrochloride (DOX-H) degradation. Benefitting from synergy effects of porous carbon structure, nitrogen doping, and fine dispersion of Fe 3 O 4 nanoparticles, Fe 3 O 4 /NCMS showed excellent DOX-H degradation efficiency within 20 min via PMS activation. Further reaction mechanisms revealed that the reactive oxygen species including hydroxyl radicals (•OH) and singlet oxygen (1O 2) played the dominant role for DOX-H degradation. Moreover, Fe(II)/Fe(III) redox cycle also participated in the radical generation, and nitrogen-doped carbonaceous structures served as the highly active centers for non-radical pathways. The possible degradation pathways and intermediate products accompanying DOX-H degradation were also analyzed in detail. This study provides key insights into the further development of heterogeneous metallic oxides-carbon catalysts for antibiotic-containing wastewater treatment. [Display omitted] • Fe 3 O 4 /NCMS significantly enhanced DOX-H removal by activating PMS. • Both radical and nonradical processes contributed to the degradation of DOX-H. • The PMS activation coordinated with the Fe valence change, carbonaceous structures, and nitrogen doping. • A possible pathway for DOX-H degradation in the Fe 3 O 4 /NCMS/PMS system was proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A fascinating magnetic gray flower-shaped yolk-shell like structure composite was synthesized successfully. • The FNCM has magnificent adsorption performance for As(V) and Re(VII). • The appearance, structure and adsorption mechanisms of FNCM were explored in detail. A novel magnetic flower-shaped yolk-shell like structure composite Fe 3 O 4 @NC@MnO 2 (Fe 3 O 4 nanostructures coupled with N-doped carbon and MnO 2 , denoted as FNCM) was successfully fabricated through a facile and scalable tactic. By batch experiments, the maximal removal capacites of FNCM towards Re(VII) and As(V) can reach 110.9 and 236.3 mg/g at 293 K, respectively. Besides, the formed FNCM had excel dispersion, moderate specific surface area (46.23 m2/g) and saturation magnetization (∼20 emu/g). Next, the adsorption performance of FNCM towards Re(VII) and As(V) was investigated as function of contact time, pH, interfering ions and solution temperature. It was indicated that FNCM possessed wonderful adsorption performance towards Re(VII) and As(V) elimination under the acidic condition, rarely affected by other co-existing ions under the same concentration, and exhibited higher removal capacity. Furthermore, On the base of zeta potential and microscopic spectra analysis, the adsorption mechanism of FNCM towards Re(VII) and As(V) can be drown to three aspects: complexation between Re(VII)/As(V) and oxygen-containing functional groups (oxide–metal bonds (O–M bonds)), electrostatic interaction, and protonated N adsorption. In all, these results imply that the FNCM could be as a potential candidate for remediating water contaminated with practical applications. [ABSTRACT FROM AUTHOR]

A simple, practical and gram-scale process for direct transformation of primary alcohols or silyl ethers to ammonium salts was developed. This method has the feathers of easy work-up (a simple filtration), mild condition, high yield, great practicality and robustness. And the application of the ammonium salts in Suzuki coupling reaction was also accomplished. Image 1 • A simple, practical and gram-scale process for direct transformation of alcohols or silyl ethers to ammonium salts. • Easy work-up (a simple filtration), mild condition, high yield, great practicality and robustness. • Application of the ammonium salts in Suzuki coupling reaction. [ABSTRACT FROM AUTHOR]

At present more than 250 FDA approved chlorine containing drugs were available in the market and many pharmaceutically important drug candidates in pre-clinical trials. Thus, it is quite obvious to expect that in coming decades there will be an even greater number of new chlorine-containing pharmaceuticals in market. Chlorinated compounds represent the family of compounds promising for use in medicinal chemistry. This review describes the recent advances in the synthesis of chlorine containing heterocyclic compounds as diverse biological agents and drugs in the pharmaceutical industries for the inspiration of the discovery and development of more potent and effective chlorinated drugs against numerous death-causing diseases. Image 1 • The applications of chlorine in medicinal chemistry is one of the fastest growing hot research areas in the chemistry community. • More than 250 FDA approved chloro-containing drugs are in the market. • This review summarizes nearly 130 FDA approved drugs against diverse biological agents. • Discussions of the SAR of potent drugs were included. [ABSTRACT FROM AUTHOR]

Highlights • SnO 2 /NaNbO 3 nanocomposite humidity sensor was prepared by hydrothermal synthesis. • SnO 2 /NaNbO 3 had a high surface area because of a micro-sized urchin-like structure. • SnO 2 /NaNbO 3 exhibited remarkable sensitivity much higher than that of pure SnO 2. • SnO 2 /NaNbO 3 showed rapid response and recovery times and excellent selectivity. • SnO 2 /NaNbO 3 sensors have potential applications in the humidity-sensing field. Abstract An urchin-like nano-composite of SnO 2 /NaNbO 3 was fabricated by the hydrothermal method and the influence of the Sn/Nb ratio in the samples on their humidity-sensing properties was investigated. The phases and morphologies of these composites and their elemental distributions were analyzed by X-ray diffraction scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The sensor based on the optimum Sn/Nb ratio of 1:0.4 exhibited remarkable humidity-sensing properties, including a good response (S = 4823.8) that was 8.72 times higher than that of the pure SnO 2 sensor (S = 553.01). The composites showed rapid response and recovery times (3/9 s), as well as good stability, linearity, and excellent selectivity. The fabrication and humidity-sensing mechanisms were systematically analyzed using analog computations and Nyquist diagrams, respectively. Compared with pure NaNbO 3 and SnO 2 sensors, our easily prepared SnO 2 /NaNbO 3 sensor demonstrates good sensing properties and holds great promise for use in humidity-sensing applications. [ABSTRACT FROM AUTHOR]

Graphical abstract One dimensional Au nanoparticles-functionalized magnetic N-doped carbon nanotubes have been fabricated, which was employed as a novel matrix for enzyme immobilization to develop highly sensitive biosensors. Highlights • A convenient and efficient method was developed to prepare magnetic NCNTs@Fe 3 O 4 supported Au NPs. • One-dimensional NCNTs@Fe 3 O 4 @Au composite was exploited as a biosensing scaffold to entrap cyt c. • The magnetic NCNTs@Fe 3 O 4 @Au based sensor could avoid the modification on the electrode and realize the direct detection in the solution. • The resultant biosensors displayed good performance for the detection of H 2 O 2 with a low detection limit of 0.3 μM. Abstract In recent years, the fabrication of noble metal functionalized magnetic carbon nanotubes for a variety of novel biosensors has aroused considerable interest owing to their synergistic improved sensitivity. In the paper, the Fe 3 O 4 and Cu nanoparticles (NPs) were integrated into the NCNTs to obtain N-doped carbon@Fe 3 O 4 -Cu nanotubes (NCNTs@Fe 3 O 4 @Cu) through a one-pot high temperature decomposition procedure. Then, Au NPs were assembled on the magnetic NCNTs to obtain NCNTs@Fe 3 O 4 @Au composite by galvanic replacement with Cu NPs. The resultant composite had provided a friendly platform for enzyme immobilization to develop highly sensitive biosensors. After the cytochrome c(cyt c) was accumulated by NCNTs@Fe 3 O 4 @Au composite, the cyt c/NCNTs@Fe 3 O 4 @Au gathered to the surface of electrode with an external magnet. Thus, the sensitivity of designed biosensor could be further improved, and most of electrochemical interferences could be excluded. Benefiting from the unique hybrid structure of the composite, the direct electron transfer of cyt c was highly facilitated and the constructed biosensors exhibited good performance for the detection of H 2 O 2 with an extraordinary low detection limit of 0.3 μM, which revealed potential application for fabricating novel electrochemical biosensors. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Cubic perovskite was successfully synthesized by a facile solvothermal method. • Inner-sphere complexation dominated U(VI) sequestration under neutral condition. • Carbonate inhibited the sequestration and photocatalytic reduction of U(VI). Abstract Cubic perovskite (CaTiO 3) was successfully synthesized by a facile solvothermal method and was utilized to sequestrate U(VI) from aqueous solutions. The batch experiments revealed that carbonate inhibited U(VI) sequestration at pH > 6.0 due to the formation of uranyl-carbonate complexes. The maximum sequestration capacity of U(VI) on perovskite was 119.3 mg/g (pH 5.5). The sequestration mechanism of U(VI) on perovskite were investigated by XPS and EXAFS techniques. According to XPS analysis, the presence of U(IV) and U(VI) oxidation states revealed the photocatalytic reduction of U(VI) by perovskite under UV–vis irradiation. In addition, photocatalytic reduction performance significantly decreased in the presence of carbonate. Based on EXAFS analysis, the occurrence of U-Ti and U-U shells revealed the inner-sphere surface complexation and reductive precipitation of U(VI) on perovskite. These findings herein are crucial for the application of perovskite-based composites in the decontamination of U(VI) in aquatic environmental cleanup. [ABSTRACT FROM AUTHOR]

Abstract A well-organized quasi-solid-state electrolyte is formed by binary mixtures of bisamide and valine as co-gelator via intermolecular hydrogen bonds. It is interesting that the ratio of the two components of quasi-solid-state electrolyte can be tuned to shift the position of TiO 2 conduction band edge, which can obviously enhance the driving force of electron injection process. Consequently, compared with the liquid electrolyte based dye-sensitized solar cell DSSC, the short-circuit current density (J sc) of solar cellassembled by this quasi-solid-state electrolyte is increased about 12%. Moreover, the intensity-modulated photocurrent spectroscopy/intensity-modulated photovoltage spectroscopy (IMPS/IMVS) and electrochemical impedance spectroscopy (EIS) are carried out to investigate the influences of gelation on the kinetic processes of electron transport and recombination in DSSC. It is found that with the increasing of valine, the 3D network of quasi-solid-state electrolyte becomes looser and the electron transportation process is accelerated, meanwhile, the electron recombination lifetime is prolonged. As result, the quasi-solid-state solar cells (QS-DSSCs) employed with the bi-component quasi-solid-state electrolytes obtained a higher efficiency of 6.1% at AM 1.5 (100 mW cm2), but the efficiency of QS-DSSC based on the unitary component quasi-solid-state electrolyte formed by bisamide is only 5.3%. More importantly, these QS-DSSCs exhibit more excellent photo-thermal stability than the liquid electrolyte based DSSC. Graphical abstract Image Highlights • The quasi-solid-state electrolyte formed by bisamide and valine. • The conduction band of TiO 2 can be shifted by changing the components of gel electrolyte. • The photogenerated electron injection efficiency enhanced obviously in the QS-DSSC. • The QS-DSSC exhibits high photocurrent and more stability than the corresponding liquid DSSC. [ABSTRACT FROM AUTHOR]

The NiAl layered double hydroxides (NiAl-LDHs) as well as NiAl layered double oxides (NiAl-LDO T , T: 300, 400, 500, 600 °C) were successfully synthesized by hydrothermal process and calcination treatment, and served as adsorbents for the efficient uptake of arsenate (As(V)) from aqueous solutions. Batch experiments were carried out at various solution pH, original As(V) concentration, contact time and calcination temperature. It was found that As(V) adsorption capacity on these composites can be changed by controlling the calcination temperature, and followed the order NiAl-LDO 500 (198.1 mg/g) > NiAl-LDO 400 (180.9 mg/g) > NiAl-LDO 300 (160.2 mg/g) > NiAl-LDO 600 (121.4 mg/g) > NiAl-LDH (60.7 mg/g), which could be ascribed to abundant surface adsorption sites and a “memory effect” provided by “Ni-O or Al-O” bonds. The thermodynamic experiments revealed that the elimination of As(V) was spontaneous and endothermic. In addition, multiple characterizations and batch experiments have been carried out to prove the surface adsorption and intercalation by rebuilding of primary layered structure contributed to As(V) adsorption. This discovery can provide a new insight into the elimination of As(V) from wastewater for environmental remediation. [ABSTRACT FROM AUTHOR]

The discharge of microplastics into aquatic environment poses the potential threat to the hydrocoles and human health. The fate and transport of microplastics in aqueous solutions are significantly influenced by water chemistry. In this study, the effect of water chemistry (i.e., pH, foreign salts and humic acid) on the surface charge and aggregation of polystyrene microsphere in aqueous solutions was conducted by batch, zeta potentials, hydrodynamic diameters, FT-IR and XPS analysis. Compared to Na + and K + , the lower negative zeta potentials and larger hydrodynamic diameters of polystyrene microspheres after introduction of Mg 2+ were observed within a wide range of pH (2.0–11.0) and ionic strength (IS, 0.01–500 mmol/L). No effect of Cl − , HCO 3 – and SO 4 2− on the zeta potentials and hydrodynamic diameters of polystyrene microspheres was observed at low IS concentrations (<5 mmol/L), whereas the zeta potentials and hydrodynamic diameters of polystyrene microspheres after addition of SO 4 2− were higher than that of Cl − and HCO 3 – at high IS concentrations (>10 mmol/L). The zeta potentials of polystyrene microspheres after HA addition were decreased at pH 2.0–11.0, whereas the lower hydrodynamic diameters were observed at pH < 4.0. According to FT-IR and XPS analysis, the change in surface properties of polystyrene microspheres after addition of hydrated Mg 2+ and HA was attributed to surface electrostatic and/or steric repulsions. These investigations are crucial for understanding the effect of water chemistry on colloidal stability of microplastics in aquatic environment. [ABSTRACT FROM AUTHOR]

Sandwich-like structure of graphene oxide (GO) @SiO 2 @C-Ni nanosheets were prepared by combining an extended stöber method with subsequent carbonization treatment, in which polydopamine was used as reducing agent and carbon source. Firstly, the GO nanosheets were covered with SiO 2 interlayer and finally coated with a outer shell of nickel ion doped polydopamine (PDA-Ni 2+ ) with an extended stöber method. Followed by a carbonization to produce the GO@SiO 2 @C-Ni sheets with metallic nickel nanoparticles embedded in PDA-derived thin graphic carbon layer. Notably, silica interlayer played a vital role in the formation of such GO@SiO 2 @C-Ni sheets. Without the protection of SiO 2 , the hydrophobic graphene@C-Ni composites were obtained instead. While with silica layer as the spacer, the obtained hydrophilic GO@SiO 2 @C-Ni composites were not only well dispersed in the solution, but also can be adjusted in terms of the size and density of Ni nanoparticles (NPs) on surface by changing the calcination temperature or the molar ratio between dopamine and nickel salt. Furthermore, nickel nanoparticles decorated on GO@SiO 2 sheets were employed to enrich His-rich proteins (BHb and BSA) via specific metal affinity force between polyhistidine groups and nickel nanoparticles. [ABSTRACT FROM AUTHOR]

The very large surface associated with aerogels made them attractive in the field of sorption. Herein, silica aerogels were characterized and used for the sorption of U(VI) in solution. The effects of specific surface area (SSA), pH and coexistent electrolyte ions on the surface site density, aggregation and sorption properties have been carefully investigated. The site distributions of silica aerogels were calculated with Visual MINTEQ. The sorption of U(VI) is affected significantly by the solution pH. The sorption increases with increasing SSA due to the increased amount of surface active sites of silica aerogels. Electrolyte ions (Na + , K + , NO 3 − , Cl − ) were added to investigate the competition ability to U(VI) adsorbed on active sites. The influence of humic acid (HA), silicate and phosphate on U(VI) sorption in multiphase systems were also discussed. The kinetics data were used to investigate the sorption process and pseudo-second-order model was used to simulate the kinetic data. Spectroscopic analyses were also utilized to explain the role of OH groups in the U(VI) sorption. [ABSTRACT FROM AUTHOR]

Europium (Eu(III)) has been extensively used as an analogue of trivalent lanthanide in the radioactive wastewater from nuclear industry. The adsorption of Eu(III) on the Al-substituted goethite was investigated by characteristic and batch techniques. The characteristic results illustrated that the Al-substituted goethite was synthesized successfully and the acicular-like structure goethite was transformed to multi-domain jagged crystal with the increase of Al content, respectively. The adsorption amount of Eu(III) on Al-substituted goethite was increased with an increase of pH from 4.0 to 8.0. The thermodynamic parameters revealed that the adsorption of Eu(III) on Al-substituted goethite was a spontaneous and endothermic process. The increase of Al content increased the adsorption capacity of Al-substituted goethite to Eu(III). The maximum Eu(III) adsorption capacity was determined to be 6.75 mg/g for α-(Fe 0.85 Al 0.15 )OOH at pH = 5.5 and T = 293 K using Langmuir model. Furthermore, XPS (X-ray photoelectron spectroscopy) analysis verified that oxygen-containing functional groups were responsible for the major adsorption mechanism and the effect of ionic strength on the adsorption displayed the inner-sphere surface complexation of Al-substituted goethite dominated the adsorption process. [ABSTRACT FROM AUTHOR]

The uncalcined glycerol-modified nanocrystallined Mg/Al layered double hydroxides (named as G-LDH) and calcined G-LDH (named as G-LDO) with molar ratio of Mg:Al = 3:1 were successfully synthesized using an easy and green hydrothermal method, and were characterized by scanning electron microscopy, transmission electron microscopy, N 2 Brunauer–Emmett–Teller surface area measurement, Fourier transformed infrared (FT-IR) spectroscopy and X-ray diffraction (XRD). The as-synthesized G-LDH and G-LDO were applied as adsorbents to remove methyl orange (MO) from aqueous solutions at different experimental conditions, and the results showed that the interaction of MO with G-LDH and G-LDO were strongly pH-dependent and ionic strength-independent. Kinetic study indicated the MO adsorption on G-LDH and G-LDO were well simulated by pseudo-second-order model. The MO adsorption on G-LDH and G-LDO were well simulated by Langmuir model, and the maximum adsorption capacity of G-LDO (q max = 1062.3 mg/g) was much higher than that of G-LDH (q max = 443.5 mg/g) at pH = 4.5. The thermodynamic parameters calculated from temperature-dependent isotherms indicated that the adsorption was spontaneous and exothermal process. The FT-IR and XRD analysis further evidenced that the interaction of MO with G-LDH was mainly dominated by electrostatic interaction, ion exchange, hydrogen bonding and surface complexation, whereas the uptake of MO to G-LDO was mainly attributed to electrostatic interaction and surface complexation. These results suggested that the G-LDO was a promising material for the efficient removal of organic pollutants in real environmental pollution cleanup. [ABSTRACT FROM AUTHOR]

Fe 3 O 4 nanoparticles were synthesized by hydrothermal technique and then modified with tetraethyl orthosilicate to form Fe 3 O 4 @SiO 2 nanospheres through Stöber method. The characterization results of X-ray diffraction, Fourier transformed infrared spectroscopy, transmission electron microscopy, scanning electron microscopy and magnetic measurements evidenced the successful synthesis of Fe 3 O 4 @SiO 2 nanospheres. The as-prepared Fe 3 O 4 @SiO 2 was applied as adsorbent to remove congo red (CR) from aqueous solutions at different experimental conditions, and the results indicated that CR adsorption on Fe 3 O 4 @SiO 2 was strongly pH-dependent and weakly ionic strength-dependent at relative low pH values, indicating that the adsorption was mainly dominated by electrostatic interactions. The maximum adsorption capacities of CR on Fe 3 O 4 @SiO 2 were calculated to be 54.64 mg/g from Sips model and 50.54 mg/g from Langmuir model at T = 308 K and pH = 5.3. The thermodynamic parameters calculated from temperature-dependent isotherms indicated that the adsorption of CR on Fe 3 O 4 @SiO 2 was an spontaneous and endothermic process. The CR-adsorbed Fe 3 O 4 @SiO 2 nanospheres could be easily separated from aqueous solutions using magnetic separation technique within 40 s. These results suggested that the Fe 3 O 4 @SiO 2 nanospheres might be suitable materials for the efficient separation of dye pollutants from aqueous solutions in possible real applications. [ABSTRACT FROM AUTHOR]

Understanding the rate and extent of 63 Ni(II) sorption and desorption on/from mineral surfaces are important to predict its mobility performance in the natural environment. We herein systematically investigated the effects of pH, electrolyte cations, humic acid (HA) and temperature on 63 Ni(II) sorption/desorption on/from Na-montmorillonite. The results indicated that the sorption/desorption of 63 Ni(II) on/from Na-montmorillonite were strongly dependent on pH and electrolyte cations. Desorption abilities of 63 Ni(II) were Na + ≈ K + > Ca 2+ ≈ Mg 2+ at the cationic concentration of 0.2 mol/L, which was associated with the clay tactoid size. The kinetic results suggested that 63 Ni(II) sorption/desorption initially increased rapidly and remained constant as time increasing. The presence of HA influenced 63 Ni(II) sorption clearly and promoted 63 Ni(II) desorption as a result of the dissolution of ternary surface complexes. Increasing temperature was favorable for the sorption reaction owing to the formation of strong inner-sphere complexes, however, hampered the desorption reaction because of the increased stability of inner-sphere complexes or the aggregation of montmorillonite. The results are crucial to understand the physicochemical behavior of radionickel in the natural environment. [ABSTRACT FROM AUTHOR]

• SnO 2 /DE nanocomposite was prepared by hydrothermal synthesis. • SnO 2 /DE had a high surface area because of a micro-sized embedded structure. • SnO 2 /DE exhibited remarkable sensitivity much higher than that of pure DE. • SnO 2 /DE showed rapid response and recovery times, excellent water adsorption and desorption properties. • SnO 2 /DE sensors have potential applications in the humidity sensing and controllable field. A tin oxide/diatomaceous earth (DE) composite was synthesized via the hydrothermal method without using a template or surfactant, and its humidity-sensing and controlling properties were investigated. The SnO 2 /DE composites have a special embedded structure, in which SnO 2 nanoparticles are embedded in the DE porous frame. The optimal composites exhibit short response and recovery times (T = 3 and 8 s, respectively), and their response (S = 35.64) is 11.88 times higher than that of DE (S = 3). Furthermore, the optimal composite C-1:3 was tested to determine its humidity-controlling properties, which revealed that it possessed absorption (27 h, 12.04%) and desorption (5 h, 8.56%) characteristics. Regarding the selectivity, the C-1:3 sensor showed better sensing behavior to humidity than to NO 2 , NH 3 and other gases. These beneficial properties of the composites are due to a honeycomb structure that endows the composite with a large specific surface area for adsorption of H 2 O molecules and allows charge transfer between the embedded SnO 2 nanoparticles. The humidity-sensing mechanism is explained in detail by the Grotthuss proton transfer theory and density functional theory (DFT), which were used together with a Nyquist diagram to analyze the conditions of H 2 O adsorption. This study demonstrates a novel strategy for designing a material that can rapidly sense and control humidity and provides insights into the application of the composite in sensing and controlling environmental humidity at room temperature. [ABSTRACT FROM AUTHOR]