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[Display omitted] In the context of industrialization and severe wastewater pollution, mercury ions pose a major threat due to their high toxicity. However, traditional adsorbents and common metal-organic framework (MOF) materials have limited effectiveness. This study focuses on combining magnetic materials with functionalized titanium-based MOF composite (SNN-MIL-125(Ti)@Fe 3 O 4) to improve mercury ion adsorption. Through comprehensive characterization and analysis, the adsorption performance and mechanism of the material were studied. The optimal adsorption of the material was achieved at pH 5, exhibiting a pseudo-second-order adsorption model and the Hill theoretical capacity of 668.98 mg/g. Hill and Tempkin models confirmed the presence of chemical and physical adsorption sites on the material surface. Thermodynamic experiments showed a spontaneous endothermic process. Despite the presence of interfering ions, the material exhibited high selectivity for mercury ions. After four cycles, adsorption performance decreased by only 8%, indicating excellent reusability. Nitrogen- and sulfur-containing functional groups played a key role in mercury ion adsorption. In conclusion, SNN-MIL-125(Ti)@Fe 3 O 4 , as a magnetic MOF adsorption material, showed potential for effective remediation of mercury-contaminated wastewater. This study contributes to the development of efficient adsorption materials and enhances the understanding of their mechanism. [ABSTRACT FROM AUTHOR]

With the development of industry, the concentration of lead (Pb) in water bodies is gradually increasing, the forms of Pb pollution in water are becoming increasingly diversified, and the environmental and human health hazards caused by Pb pollution are receiving increasing attention. A HCO–(Fe3O4)x composite adsorbent prepared by the coprecipitation method of Fe3O4 mixed in cerium-rich grinding and polishing sludge was used to remove Pb from water. The effects of Ce/Fe molar ratio, pH, dosing amount, and time on the adsorption of HCO–(Fe3O4)x for Pb removal were investigated and the adsorption isotherm model, adsorption kinetics, and adsorption mechanism were studied. The results showed that the maximum adsorption capacity of HCO–(Fe3O4)x on Pb(II) was 35.93 mg·g−1 at a Ce/Fe molar ratio of 1.5:1, pH 4–5, and temperature of 25 °C, and the removal rate could reach 96.05%; the process of Pb(II) adsorption by HCO–(Fe3O4)x was in accordance with the Langmuir isothermal adsorption model and the pseudo-second-order reaction kinetic model; chemisorption was dominant. Characterization results, such as EDS, XRD, and XPS, showed that the composite preparation of HCO with Fe3O4 increased the specific surface area of HCO–(Fe3O4)x and generated amorphous iron oxides, such as FeCe2O4, FeOOH, Fe3O4, and Fe2O3, which provided conditions for the formation of Fe-O-Pb and Ce-O-Pb complexes during the adsorption process, thus facilitating the adsorption removal of Pb(II). [ABSTRACT FROM AUTHOR]

Chemical sand-fixing technology has shown good potential in preventing desertification, but the effect is determined by materials. In this paper, the adsorption behavior of quartz and six common polymer sand-fixing agents under dry conditions was studied by molecular dynamics method. The results show that all polymers could be adsorbed on the surface of quartz and their functional groups play an important role in the adsorption process. Compared with other materials, the binding energy and the number of hydrogen bonds of PAA-quartz composites were improved by 30.7–65.6% and 8.3–333.3%, respectively. It was found that the number of hydrogen bonds formed under the unit molecular was positively correlated with the mechanical properties of the improved sandy soil. This study provides an accurate, efficient and inexpensive qualitative evaluation method for the curing effect of sand fixers, which will assist in the screening and development of new high performance sand fixers. [ABSTRACT FROM AUTHOR]

• Molecular dynamic of phenolic organic pollutants (POPs) adsorption on UiO-66. • The adsorption behavior of POPs molecules occurred on the surface of UiO-66. • UiO-66 has highest adsorption capacity for nitrophenol due to the larger interaction of host–guest. • The interaction energy and π-π stacking are quantificationally calculated. • Van der Waals and π-π stacking dominate adsorption between POPs and UiO-66. Metal organic frameworks (MOFs) as an excellent adsorbent have been widely utilized in wastewater treatment due to high specific surface area, high porosity, adjustable structure and surface functionability. To design MOFs materials based on the application for removal of pollutant, understand the adsorption mechanism between pollutant and MOFs from the microscopic scale is necessary but rare. Herein, UiO-66 is selected as the adsorbent to investigate the adsorption mechanisms with phenolic organic pollutants (POPs) on the microscopic scale via MD simulation. Equilibrium configuration and density distribution for three different POPs (phenol, nitrophenol and bisphenol) prove the adsorption behavior occurred on the surface of UiO-66. Obviously, the difference of adsorption capacity proves UiO-66 tends to adsorb the nitrophenol compared to other two molecules and has the lower adsorption capacity for bisphenol due to larger molecule size, and in a neutral environment, it is more conducive to be adsorbed than in an alkaline environment. Mean square displacement (MSD) and radial distribution functions (RDFs) further support this conclusion, which exhibit the introduction of –NO 2 groups can enhance the interaction of host–guest. The H-bonds, π-π stacking and interaction energy between UiO-66 and POPs was quantificationally calculated, the results show Van der Waals and π-π stacking dominate adsorption between POPs and UiO-66. [ABSTRACT FROM AUTHOR]

To evaluate the synergetic adsorption capacity of layered double hydroxide (LDH) and photocatalytic reduction property of TiO 2 for aqueous Cr(VI), the Fe 3 O 4 -ZnAl-LDH and TiO 2 composites (FLT) were prepared via sol-gel method. The removal efficiency of FLT composites for Cr(VI) changed with the mass ratio of Fe 3 O 4 -LDH/TiO 2 , and the optimal ratio was 20% (FLT-2). The adsorption efficiencies of 100 mg FLT-2 were 74% and 64% for 20 and 50 mg/L Cr(VI) solution, and the total removal ratios of Cr(VI) were all over 97% after UV irradiation. The experimental data of adsorption kinetic, adsorption isothermal, and photocatalytic reduction were consistent with the pseudo-second-order, Langmuir, and first-order reaction equations, respectively. From the X–ray photoelectron spectra analysis, FLT composites adsorbed Cr(VI) directly via surface complexation, also reduced aqueous Cr(VI) to Cr(III). The photocurrent and electrochemical impedance spectroscopy of FLT composites indicated the photo-induced electron-hole pairs were separated effectively. The regeneration results show that the FLT composites had good stability and reusability after five consecutive cycles. Therefore, FLT composites are promising materials in the disposal of wastewater containing Cr(VI). [ABSTRACT FROM AUTHOR]

[Display omitted] • LC-90 exhibits a superior adsorption capacity at low phosphate concentrations. • LC-90 is insensitive to pH and ionic strength. • The adsorption performance for phosphate of the LCs is related to the La species. • The ion exchange capacity is the major factor affecting low-level phosphate removal. The low-level phosphorus (P) removal is increasingly becoming a challenge for P pollution control and prevention. Adsorption is a highly efficient method for achieving low-level P removal. The development of adsorbents with a strong affinity towards P and the study of limiting factors affecting low-level P removal are currently of primary importance. In this study, lanthanum carbonates (LCs) synthesized at different temperatures, designated as LC-80, LC-90 and LC-100, were compared. It was found that the synthesis temperature determined the La species and thus the ion exchange capacity, which further affected the P adsorption capacity of the LCs at low P concentrations. LC-80 and LC-90 were novel LC species (La 2 O(CO 3) 2), exhibiting a higher ion exchange capacity. They combined with P through ion exchange to form inner-sphere complexes. LC-100, which was determined as LaCO 3 (OH), exhibited a lower ion exchange capacity and adsorbed P anions through ion exchange and electrostatic attraction. Moreover, LC-80 and LC-90 displayed greater resistance to pH and co-existing ions, with LC-100 being more susceptible to their negative effects. A five-cycle regeneration operation demonstrated the good recyclability and reusability of LCs. In particular, LC-90 showed the highest P adsorption capacity at low P concentrations due to its strong ion exchange capacity. This remarkable performance allowed LC-90 to achieve an ultra-low P concentration at a lower cost of 283.12 $/kg P, thus making it a promising adsorbent for low-level P removal. [ABSTRACT FROM AUTHOR]

Abstract Nitrogen-enriched graphene coupled with nickel hydroxide nanosheets (Ni(OH) 2 /NG) hydrogel is successfully synthesized through a facile one-pot hydrothermal method. Comprehensive investigations reveal that the nitrogen atoms are successfully inserted into graphene and that the nickel hydroxide nanosheets (∼30–50 nm) are anchored on NG homogeneously. With the enhanced electroactivity caused by nitrogen doping and the synergy effect from Ni(OH) 2 nanosheets and NG, the Ni(OH) 2 /NG hydrogel electrode displays much better electrochemical properties than two individual electrodes. It features a specific capacitance as high as 896 F g−1 at 0.5 A g−1 and even 504 F g−1 at 12 A g−1 showing a high rate capability (56.3% retention with 24 times higher current density). An asymmetric supercapacitor device on the basic of Ni(OH) 2 /NG hydrogel and activated carbon (AC) was assembled and delivered a high energy density of 28.7 W h kg−1 at the power energy density of 0.36 kW kg−1. Such results indicate that the Ni(OH) 2 /NG hydrogel could be considered as a promising candidate for electrochemical supercapacitors. Graphical abstract Image 1 Highlights • The Ni(OH) 2 /NG hydrogel composite was synthesized by a facile route. • The composite electrode material displays excellent electrochemical properties. • An asymmetric supercapacitor is fabricated and exhibits a desirable energy density. • Excellent electrochemical performance is primarily attributed to the nitrogen doping and the synergy between the components. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Nb 2 O 5 -TiO 2 were synthesized by the sol-gel method. • Strong interaction between Nb 2 O 5 and TiO 2 influences the physicochemical properties. • Nb 2 O 5 -TiO 2 exhibit higher activity for 1,2-dichloroethane combustion than single metal oxides. • Synergistic catalytic effect is observed in Nb 2 O 5 -TiO 2 catalyst system. Abstract The Nb 2 O 5 -TiO 2 catalyst system was synthesized via sol-gel method and investigated for adsorption/catalytic combustion of toxic 1,2-dichloroethane (DCE), which was usually recognized as a representative of various chlorinated and brominated VOCs pollutants. The research results of structure-performance relationship revealed that binary Nb 2 O 5 -TiO 2 were amorphous and mesoporous materials with pore diameter mainly in the range of 2–10 nm, and Nb and Ti elements were uniformly dispersed. The interaction between Nb 2 O 5 and TiO 2 coupled with the molar ratio of Nb/Ti improved the physicochemical properties of Nb 2 O 5 -TiO 2. Moreover, Nb 2 O 5 -TiO 2 exhibited higher catalytic activity for DCE combustion than single Nb 2 O 5 or TiO 2. Especially, the 2Nb1Ti catalyst (Nb/Ti = 2:1, molar ratio) displayed the highest activity, over which 90% conversion of DCE could be achieved at 295 °C. These results were related to that the interaction effect between Nb 2 O 5 and TiO 2 improved acidity and oxidizing properties, and the materials had large surface area, all of which were favorable for adsorbing DCE at relatively low temperatures (below 93 °C) on Nb 2 O 5 -TiO 2 and then improving catalytic combustion performance at lower reaction temperatures than Nb 2 O 5 or TiO 2. Besides, during the long-term continuous reaction, even though partial deactivation was observed for this catalyst, it could be suppressed at elevated temperature. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Pd-Pt nanocrystals were synthesized using a high-temperature solution-phase reduction method. • PdO x or PtO x nanoparticles (2 nm) dispersed homogeneously on γ-Al 2 O 3. • CeO 2 can improve the dispersion of PdO x and PtO x nanoparticles. • 0.2%Pd-Pt(1:1)/10%Ce/γ-Al 2 O 3 had good stability and the highest activity for benzene oxidation. Abstract In this investigation, a mesoporous γ-Al 2 O 3 with large surface area and good thermal stability was synthesized and employed as the support for preparing a series of Pd-Pt nanocrystalline catalysts by using a high-temperature solution-phase reduction method. The PdO x (x = 0, 1) and PtO x (x = 0, 2) nanoparticles were found to have a small diameter (about 2 nm) and were highly dispersed on the surface of the mesoporous γ-Al 2 O 3. The results show that catalysts with the appropriate ceria greatly improved the physical adsorption/chemisorption of benzene to Pd-Pt nanocrystals, which greatly enhanced the activity to achieve the complete oxidation of benzene. The high activity of the catalyst was mainly due to the nano-effects of Pd-Pt nanocrystals and the interactions among the active components. 0.2%Pd-Pt(1:1)/10%Ce/γ-Al 2 O 3 demonstrated the best activity for the complete oxidation of benzene at 200 °C. Furthermore, this catalyst maintained 95% benzene conversion for 1000 h at 190 °C and displayed good resistance to water and Cl-poisoning, which indicated that the Pd-Pt nanocrystalline catalysts have promise for adoption by the industry. [ABSTRACT FROM AUTHOR]

Graphical abstract The Ti 4 O 7 /carbon nanofibers (TCNFs) were successfully prepared by one step electrospinning and subsequent carbothermal reduction. When served as an interlayer, the CMK3-S cathode with TCNFs showed excellent cycling and high-rate performances. Highlights: • TCNFs were obtained easily-via electrospinning followed by in-situ carbonreduction. • The interlayer has both physical blocking and chemical adsorption effects for LiPSs. • Ti 4 O 7 chemical binding of LiPSs by Ti-S bonds greatly reduces LiPSs shuttle. • The 3D TCNFs make for lower interfacial resistance and faster redox reaction. • Li-S battery exhibits excellent electrochemical performances, even at high rates. Abstract In this work, a free-standing and flexible Ti 4 O 7 /C nanofibers (TCNFs) interlayer is prepared via one-step electrospinning. The TCNFs interlayer acts as both physical barrier and chemical adsorption agent for lithium polysulfides (LiPSs), in which the 3D CNFs network with large volume and high conductivity contributes to LiPSs conversion and electron transfer, while the ‘sulphiphilic’ Ti 4 O 7 with strong chemical bonding to the soluble long-chain LiPSs contributes to less LiPSs dissolution and higher coulombic efficiency. In a lithium-sulfur (Li-S) cell, CMK3/S cathode with TCNFs interlayer exhibits greatly enhanced electrochemical capability than CMK3/S with CNFs interlayer and without interlayer, and a capacity of 560 mAh g−1 after 1000 cycles is obtained under a high current density of 1 C. Even at 3 C, the capacity decay is merely 0.030% per cycle over 2500 cycles. Notably, the simple, affordable and scalable fabrication method to form a controllable free-standing interlayer that brings a novel horizon on material structure design and performance improvement in practical application of Li-S batteries. [ABSTRACT FROM AUTHOR]

In this study, nanoscale zero-valent iron nanoparticles (NZVIs) were coated with silica and polydopamine using a two-step process. The coated nanoparticles were applied as adsorbents for removal of two common polycyclic aromatic hydrocarbons pollutants, phenanthrene (PHE) and anthracene (ANT) from aqueous system. Adsorption kinetics followed a pseudo-second-order model. Isotherms and thermodynamics were investigated and the results indicated that the adsorption process fit best to the Freundlich model and exhibited the characteristics of an exothermal physical adsorption process. Owing to their superparamagnetic characteristics and stability, these adsorbents could be easily collected and recycled for reuse. [ABSTRACT FROM AUTHOR]

[Display omitted] • Adsorption of methane, ethane, and their binary mixture on shale were measured. • Predictions of IAST and EL on high-pressure binary gas adsorption were compared. • Methane/ethane adsorption selectivity is positively correlated with TOC. • Gas-in-place of methane/ethane mixture was estimated. • A two-stage trend of falling followed by rising for GIP vs. TOC was observed. Methane and ethane are the two most abundant hydrocarbon species in shale gas, while the adsorption behavior of their binary mixture in shale is still ambiguous. In this study, the adsorptions of methane, ethane, and their binary mixture on twelve dried mature lacustrine organic-rich shale samples were measured at 60 °C and variable pressures ranging from 0.001 to 30 MPa. The Langmuir and supercritical Dubinin–Radushkevich (SDR) models combined with the ideal adsorbed solution theory (IAST) and Extended Langmuir (EL) model were used to describe the raw adsorption isotherms. By contrast, the Langmuir model with consistent adsorbed phase volume can better describe the ethane excess adsorption. The IAST and EL models matched binary gas excess adsorption equally well. The adsorption capacity of pure ethane was about 1.6 times as large as pure methane, while the Langmuir pressure for ethane was lower. For the adsorption of pure and binary gas, organic matter was the primary contributor, followed by clay minerals. The adsorption selectivity of ethane over methane ranged from 3.49 to 8.85, which strongly depended on total organic carbon (TOC), and weakly negatively correlated with clay mineral content. The estimated gas-in-place (GIP) of binary gas ranged from 4.57 cm3/g to 8.08 cm3/g, which was about 30% larger than that of pure methane. A two-stage trend, first falling and then rising, was observed in relationship between binary gas GIP and TOC. This phenomenon could be attributed to the opposite effects of residual bitumen on shale porosity and gas adsorption. This study provides better insight in the storage mechanisms of shale gas and a basis for the reliable estimation of shale gas potential. [ABSTRACT FROM AUTHOR]

Self-consistent charge density functional tight-binding simulations are performed to investigate the adjustments of adsorption behaviors of C 60 onto perfect or defective graphene owing to the applied electrical field. For the C 60 adsorbed on the perfect graphene, the effect of the applied electrical field on the physical adsorption is visually displayed from the Mulliken charges on the atoms of the C 60 -graphene nanohybrid systems. When the C 60 is adsorbed on the graphene with one vacancy, the differential charge density and optimized geometry as well as the adsorption energy are used to identify chemical, physical, or no adsorption. The applied electric field can adjust adsorption behaviors for some configurations accompanying with the atom arrangements in the graphene. [Display omitted] • For the adsorption of the C 60 on the perfect graphene, the applied electric field can significantly adjust the charge distribution on the atoms in the C 60 and graphene, resulting in modulating the physical repulsion or attraction of the C 60 -SLG system. • For the C 60 -dSLG systems without the electric field, the C 60 can be chemically adsorbed onto the graphene by forming two covalent bonds between the atoms from the 6:6 or 5:6 bond in the C 60 and the C atoms with dangling bonds in the defective graphene. • When applying the electric field, the configurations present different patterns with varying the strength and direction. • Owing the applied electrical field, there are adjustments from physical adsorption to chemical adsorption in a few of configurations. [ABSTRACT FROM AUTHOR]

The influence of alkylphenols to environment cannot be ignored, as they are common product from chemical industries and potential threat to human health. Some alkylphenols are listed as persistent toxic substances (PTS) by the United Nations Environment Programme (UNEP). In this study, the optimized magnetic reduced graphene oxide (MrGO) was synthesized by a facile solvothermal method, and investigated for adsorption of three typical alkylphenols. In neutral condition, MrGO showed extremely high adsorption capacity of three typical alkylphenols, 4-heptylphenol (4-HP), 4- tert -octylphenol (4-OP), and 4-nonylphenol (4-NP), which could reach 938.9 mg g−1 (40 °C), 987.8 mg g−1 (40 °C), and 989.7 mg g−1 (20 °C), respectively. This study revealed that the adsorption process was a heterogeneous multi-layer physical adsorption, and the adsorption rates were related to the number of unoccupied vacancies on the adsorbent surface. From batch experiments and density functional theory (DFT) calculations, the main adsorption interactions between MrGO and alkylphenols were deduced to be π–π, hydrogen-bond, and hydrophobic interactions. What's more, the different affinities of MrGO towards different targets were further distinguished and explained in detail. The wonderful stability and recyclability of MrGO made it a promising cost-effective remediation candidate. • Magnetic reduced graphene oxide exhibits excellent adsorption for target phenols. • Adsorption follows pseudo-second-order kinetics and Freundlich adsorption isotherm. • The strong adsorption was due to hydrogen-bond, π-π interaction and hydrophobicity. [ABSTRACT FROM AUTHOR]

Abstract: Graphene, a 2-D carbon material, has unique electrical properties and high specific surface area. In recent years, carbon materials were impregnated into TiO2 photocatalysts and become a research focus since the pure TiO2 has limited adsorption and photocatalytic ability. In this study, P25–graphene (GN) nanocomposite photocatalyst was prepared by hydrothermal methods. The reduction of graphene oxide and loading of TiO2 (Degussa P25) on GN were completed at the hydrothermal process. By controlling the amount of P25 and the concentration of graphene oxide dispersions, P25–graphene composite with different graphene content was prepared. The nanocomposites were characterized using TEM, XRD, N2 adsorption/desorption analyzer, UV–vis DRS and TGA. As graphene content increasing, the absorption intensity of visible light and the specific surface area was increased. The results showed that P25–graphene composite has better adsorption capacity and photocatalytic degradation efficiency for MB (methylene blue) and RBk5 (reactive black 5) dyes removal. For 10mgL−1 MB, the adsorption removal efficiency can reach above 90% with P25–10% GN dosage of 0.4gL−1. The saturated adsorption capacity of MB is 50mgg−1 under the same condition. For 10mgL−1 RBk5, the degradation removal efficiency can reach more than 90% with 365nm UV light irradiation. [Copyright &y& Elsevier]

Abstract: We prepared tri-isocyanate reinforced graphene aerogel with a low bulk density (0.08g/cm3), high compressive failure strength (0.24MPa), and good adsorption ability towards crude oil (∼169mg/g), through self-assembly of graphene under hydrothermal condition, tri-isocyanate reinforcement and subsequent supercritical CO2 drying process. [Copyright &y& Elsevier]

There has been a significant interest in many technical applications and natural phenomena concerning two-phase mixture discharges (TPMDs). Few studies have focused on the influences of different macroparticles on TPMDs. The dielectric constant is usually considered to be the only factor affecting the discharges, but in this paper, 21 kinds of different dielectric materials were used to investigate the effects on TPMDs. By the experimental results, this paper reveals the effects of macroparticle sizes, and the dielectric constant has little influence. When the diameter of TPMs is less than about 0.01 mm, the percentage of the selection of TPMs is always smaller than 50%, the discharge path selects the air but TPM, and the breakdown voltage is higher than that in air. However, when the diameter is greater than about 0.1 mm, the conclusion is opposite. When the diameter is in the range of 0.01–0.1 mm, the TPMDs have a polarity effect. The dipole-enhanced approximation model is applied to explain the experimental phenomena. It is very important in TPMDs that the macroparticle dielectric constant, the saturation charge, and the adsorption/desorption process on the material, except the effects of TPMDs, are highly correlated with the macroparticle sizes. [ABSTRACT FROM AUTHOR]

Abstract: A low-temperature gas sorption study has been carried out on four three-dimensional microporous metal organic framework (MMOF) structures and two two-dimensional layered structures. The pore characteristics are analyzed based on the argon adsorption–desorption isotherms at 87K. The results from hydrogen sorption experiments conducted at 77 and 87K show that all MMOFs have a relatively high hydrogen uptake, with adsorbed hydrogen densities falling in the range of liquid hydrogen. Isosteric heats of hydrogen adsorption data calculated based on the Clausius–Clapeyron equation are consistent with these observations, indicating strong sorbent–sorbate interactions. [Copyright &y& Elsevier]

• CH 4 , C 2 H 6 and CO 2 adsorption in kerogens are investigated at a molecular scale. • The corresponding sorption-induced swelling of the kerogen is analyzed. • A relation between volumetric strain and absolute adsorption amount is developed. • A theoretical model for excess adsorption coupling kerogen swelling is proposed. Gas adsorption can induce kerogen swelling with changes in pore volumes. In this study, hybrid Grand Canonical Monte Carlo/Molecular Dynamics simulations are conducted to investigate gas adsorption in kerogen and the corresponding sorption-induced swelling. A unified relationship between volumetric strain and an absolute adsorption amount is developed for different adsorbates. A theoretical model for calculating excess adsorption isotherms coupling swelling is proposed. Results show that (i) steep increases in C 2 H 6 and CO 2 adsorption isotherms at lower pressure indicate stronger affinities of C 2 H 6 and CO 2 than CH 4 ; however, a larger size of C 2 H 6 results in smaller accessible pore volumes and smaller maximum absolute adsorption amounts than CH 4 and CO 2. (ii) A linear relationship between volumetric strain and an adsorption amount is shown for CH 4 , C 2 H 6 and CO 2 , separately. The volumetric strain caused by per unit of the absolute adsorption amount for C 2 H 6 is the greatest because C 2 H 6 with greater diameters has larger contact areas with pore walls for the same adsorbed amount. The maximum swelling upon CO 2 adsorption is the largest (CO 2 > CH 4 > C 2 H 6) due to its greatest absolute adsorption amount. (iii) Excess adsorption isotherms generated by our model are consistent with excess adsorption data calculated by variable pore volumes, which shows a large discrepancy compared to that determined using constant volumes, especially at high pressures. The difference between the fraction of free CH 4 in our model and that calculated by using a constant volume is up to 23.2% at 323 K, 40 MPa. Therefore, this theoretical model can accurately determine free and adsorbed gas amounts in shale, further influencing prediction of hydrocarbon production and CO 2 sequestration. [ABSTRACT FROM AUTHOR]

The exploitation of a new adsorbent with a high adsorption performance and recyclability is of great practical significance for the treatment of wastewater containing mercury ions. In this study, a novel membrane adsorbent was fabricated by blending MoS 2 nanosheets into a PVDF polymer matrix (P-PVDF/MoS 2) followed by non-solvent-induced phase conversion. This material was able to bind mercury ions and was not affected by the solution ionic strength, co-existing anions, or interfering heavy metal ions. The optimal pH range for mercury ion elimination was 4.5–6.0, and P-PVDF/MoS 2 exhibited a maximum adsorption capacity of 578 mg g−1. The pseudo-second-order adsorption kinetics and Langmuir isotherm models best described the adsorption process. The adsorption mechanism was mainly monolayer chemisorption, for which the S groups were the major active sites. Furthermore, the membrane could be removed from the aqueous solution easily using tweezers, and the removal efficiency of mercury ions remained over 90% after ten cycles. This study suggests that the inexpensive and recyclable P-PVDF/MoS 2 membranes can be used for the efficient removal of heavy metal ions from wastewater at a large scale. Image 1 • One-step blending fabrication of novel P-PVDF/MoS 2 adsorption membrane. • Removal of Hg(II) with excellent adsorption capacity and reusability. • Adsorption performance is independent of the solution environment. • Chelation, precipitation, and crystal growth were involved in the adsorption. • Shows potential in large-scale practical application for Hg(II) removal. The main finding of the work: The present work, for the first time, reports a PVDF composite membrane decorated by MoS 2 nanosheets that could remove Hg(II) ions selectively from water with high efficiency, inexpensive cost, and recyclability. [ABSTRACT FROM AUTHOR]

An adsorbed gas amount obtained from excess adsorption isotherms is of great importance to an estimation of reservoir reserves and prediction of gas production in shale reservoirs. Generally, excess adsorption amounts are calculated by a void volume of an adsorbent measured by helium expansion tests. However, helium atoms can closely approach a pore wall and get into small pores due to their small size. Therefore, a helium-based volume is always larger than the accessible volume for a specific adsorbate. In this work, we use GCMC (Grand Canonical Monte Carlo) simulation to investigate methane adsorption on shale with pore sizes of 10, 20 and 30 Å at a temperature of 323 K. Five void volumes, including an apparent volume determined by helium expansion tests, a helium-probed volume, a simulated methane-based volume, an analytical methane-based volume, and a physical volume, are recognized. Use of a physical volume and a helium-based volume leads to negative excess adsorption at high pressure, which is not consistent with local density profiles at such pressure. It is thus necessary to calibrate a physical volume or use a methane-based volume as a theoretical value for calculating excess isotherms. Excess isotherms determined by a calibrated volume or methane-based volume are more accurate and keep positive even at high pressure. Appropriate calculations of excess isotherms also influence an estimation of proportions of excess adsorbed and free gas amounts in shale gas reservoirs, further having a great impact on the determination of a development strategy. • Methane adsorption inside the slit-like pore is investigated by GCMC simulation. • Differences between helium-based volume and methane-based volume are illustrated. • A method for calibration of a physical volume is discussed. • Excess isotherms calculated by helium-based and methane-based volumes are compared. [ABSTRACT FROM AUTHOR]

[Display omitted] • CAL and PPy-CAL were prepared using hydrothermal and in situ polymerization methods. • The theoretical adsorption capacity of CAL-PPy for Cr(VI) was nearly twice than that of CAL. • CAL-PPy removed 100 mg/L of aqueous Cr(VI) efficiently and quickly. • Mechanisms included electrostatic attraction, anion exchange, complexation, and reduction. To efficiently remove high concentrations of hexavalent chromium (Cr(VI)), calcium–aluminum-layered double hydroxide (CaAl-LDH, denoted as CAL), and polypyrrole-modified CAL (CAL-PPy) were prepared by hydrothermal and in situ polymerization methods, respectively. The chemical structure, morphology, and elemental results indicated that the chain-like polypyrrole was decorated with hexagonal CAL. The specific surface area of CAL-PPy increased from 8.746 m2/g to 24.24 m2/g. The adsorption performances of CAL and CAL-PPy for aqueous Cr(VI) were investigated using batch equilibrium experiments. The decontamination process of aqueous Cr(VI) (100 mg/L) reached the equilibrium state within 50 min, and the kinetic data met the pseudo-second-order kinetic equation. The Langmuir model described the isothermal data properly, and the obtained theoretical adsorption capacity of CAL for Cr(VI) at 318 K was 34.06 mg/g, while that of CAL-PPy was 66.14 mg/g. The removal mechanisms involved electrostatic attraction, surface complexation, anion exchange, and reduction to low-toxicity Cr(III). Therefore, CAL and CAL-PPy have underlying applications in treating real wastewater containing Cr(VI). [ABSTRACT FROM AUTHOR]

A novel cyclodextrin-functionalized hybrid silicon nano-adsorbent material (6-EA-β-CD-Si) was synthesized via the nucleophilic substitution method. The structure was detected by Fourier transform infrared (FT-IR), X-ray, thermogravimetric analysis, and Brunauer-Emmett-Teller (BET) analysis. Results reveal that the BET surface area of 6-EA-β-CD-Si is 240 m2/g and the average pore size is 4.16 nm. The adsorption properties of 6-EA-β-CD-Si onto methylene blue (MB) were studied and fitted with adsorption kinetic models. Both the Freundlich adsorption isotherm model and pseudo-second-order model were fitted with well shows that the multi-layer adsorption with chemisorption and physisorption co-existing in the system. The maximum adsorption capacities are 39.37, 39.21, 36.90, and 36.36 mg/g at temperatures 303, 313, 323, and 333 K, respectively. The maximum removal rate of MB could reach 99.5%, indicating the potential application value of 6-EA-β-CD-Si in wastewater treatment. The adsorption mechanisms of 6-EA-β-CD-Si showed that the hydrophobic cave of β-CD plays an important role on the adsorption of MB. [ABSTRACT FROM AUTHOR]

• MgAl-Cys-LDH had plentiful groups beneficial for the adsorption of metal ions. • Mechanisms included precipitation, surface complexation and isomorphic substitution. • MgAl-Cys-LDH presented higher removal efficiencies in real water environment. To understand the interaction mechanisms between heavy metals and functional groups modified nanomaterials, the l -cysteine (Cys) intercalated MgAl-layered double hydroxide (MgAl-Cys-LDH) was designed by a facile co-precipitation method and used to remove Cu(II), Pb(II) and Cd(II) in water solutions. The XRD, FTIR, SEM, TEM, EDS and XPS characterization analyses proved the carboxyl, thio and amido groups were successfully introduced into MgAl-LDH. The possible mechanisms were analyzed by the XPS and XRD spectra and involved the precipitation of metal hydroxides or sulfides, surface complexation with abundant surface groups, and the isomorphic substitution of Mg(II). The adsorption kinetics and isotherms data of Cu(II), Pb(II) and Cd(II) on MgAl-Cys-LDH were well described by the pseudo-second-order kinetic equation and the Langmuir model. The influence factors such as initial solution pH of heavy metals, dosage of MgAl-Cys-LDH, adsorption time and various types of water were investigated, and the results suggested that MgAl-Cys-LDH had potential applications in real wastewater treatment containing heavy metals. [ABSTRACT FROM AUTHOR]

Abstract: Biomolecule adsorption is a fundamental process in the design of biosensors. Mechanical/electrical/thermal properties of biofilms have great influences on biodetection signals. The double-stranded DNA (dsDNA) biofilm adhered on microcantilever is treated as a bending beam with a macroscopic elastic modulus in the viewpoint of continuum mechanics. Accounting for hydration force, electrostatic repulsion and conformational entropy, moment-angle diagrams of dsDNA biofilm in pure bending state are depicted with the help of the energy conservation law and a mesoscopic liquid crystal theory presented by Strey et al. An analytical model is provided to predict macroscopic elastic modulus of dsDNA biofilm as a function of nanoscopic properties of dsDNA, packing density, buffer salt concentration and etc. The parameters for microcantilever-DNA system are obtained by curve fitting with Stachowiak’s experimental data based on a modified Stoney’s formula. Elastic modulus grows exponentially with the enhancement of packaging density, but diminishes with the increase of buffer salt concentration, and its order is about 1 ∼ 10 MPa. Conformational entropy is one of predominant factors considered in near-surface system whether in high or low salt consternation. [Copyright &y& Elsevier]

[Display omitted] • A mild method was developed to prepare the amine-functionalized cellulose aerogel. • The aerogel retains large specific surface area and low crystallinity. • Excessive graft density hinders urea adsorption. • Grafted amino or silicone hydroxy groups significantly promote urea adsorption. The development of efficient adsorbent materials to remove urea from dialysate is an effective way to solve the bottleneck limiting the development of a wearable artificial kidney. Three methods were used to fabricate amine-functionalized cellulose aerogels aiming to screen for excellent structures favorable for urea adsorption. The influence of APTES addition on the structure and adsorption performance of the adsorption materials was investigated. The kinetics and thermodynamics of urea adsorption were evaluated, and adsorption mechanisms were also discussed. Results indicate that the material prepared by the gentle method was still able to maintain a large specific surface area, large pore volume and low crystallinity. Amine-functionalized cellulose aerogels retain the original hydroxyl adsorption sites, and the amino or silanol hydroxyl as new adsorption active sites are also introduced. Furthermore, proper APTES graft density plays a critical role in the urea adsorption. The equilibrium adsorption capacity of urea on HA-N-NCA-10 is increased by 156%. [ABSTRACT FROM AUTHOR]

• Mag-LDO/C was obtained from spent adsorbent via a facile calcination method. • Mag-LDO/C presented higher adsorption capacities for Cu(II), Cd(II), and Pb(II). • The mechanisms were electrostatic attraction, precipitation, and surface complexation. To reuse the spent magnetic MgAl-layered double hydroxide after humic acid adsorption, this work provided a simple calcination method to prepare the magnetic layered double oxide/carbon (Mag-LDO/C) nanocomposite. The characterization results indicated the Mag-LDO/C was a carbonaceous composite with a large number of functional groups and superparamagnetic property. Then the adsorption performance of Mag-LDO/C for heavy metals was studied by batch experiments. The Mag-LDO/C exhibited excellent removal efficiencies for Cd(II), Pb(II), and Cu(II) with maximum adsorption capacities of 386.1, 359.7, and 192.7 mg/g, respectively. The batch sorption data were studied by the pseudo-second-order kinetic equation and the Langmuir isothermal model, and they matched well. According to the zeta potentials, X-ray diffraction patterns, and X-ray photoelectron spectra of Mag-LDO/C after heavy metals adsorption, the interaction mechanisms were ascribed to the precipitation, surface complexation, and electrostatic attraction. After reaction, the solid-liquid separation of Mag-LDO/C could quickly achieve using a magnet. Additionally, the Mag-LDH/C exhibited excellent adsorption capacities in various simulated wastewater and well sorption recyclability, proving the valuable applications of Mag-LDO/C synthesized from spent adsorbent for metal ions removal in actual water environment. [ABSTRACT FROM AUTHOR]

• Catalytic synthesis of imines from a cascade reductive imination of nitroarenes with aldehydes. • High activity and selectivity of this cascade reduction to imines enabled by PtCo/CoBO x. • Competitive adsorption of reactants/products on PtCo/CoBO x for the high catalytic performance. Catalytic synthesis of imines from one-pot cascade hydrogen reductive imination of nitroarenes with aldehydes represents a facile, green and valuable process; however, such an economical process suffers from the poor chemoselectivity due to competitive hydrogenation of aldehydes and over-hydrogenation of imines into N -alkylated amines. Herein, bimetallic PtCo nanoparticles anchored on cobalt borate nanosheets (PtCo/CoBO x) can facilitate the unparalleled activity and selectivity towards imines through the same imination. The high chemoselectivity of imines is resulted from the competitive adsorption of reactants and products on PtCo/CoBO x , including (1) weakened adsorption of imines and its uncompetitive adsorption with aromatic amines (from nitroarenes) on bimetallic PtCo to minimize its over-hydrogenation; (2) competitive adsorption of nitroarenes on PtCo and preferential adsorption of aldehydes/nitroarenes on hydroxyl-enriched CoBO x through hydrogen bond formation to suppress hydrogenation of both aldehydes and imines; and (3) kinetically and competitively preferred reduction of nitroarenes over aldehydes to avoid hydrogenation of aldehydes. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Dual-dummy-template MIPs for six PAEs were synthesized. • The MIPs exhibited good adsorption performance. • The MIPs showed favorable reusability and selectivity towards PAEs. • The MIPs were employed as the SPE adsorbent for PAEs detection. • The developed method was successfully applied to real water samples. Abstract A novel molecularly imprinted polymers (MIPs) was prepared by the sol-gel imprinting method on the surface of magnetic graphene oxide (MGO) modified with mesoporous silica (mSiO 2), with dipropyl phthalate (DPRP) and diisononyl phthalate (DINP) as the dual-dummy templates. The prepared MIPs, which was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), etc. , was subsequently employed for simultaneous separation and enrichment of six typical phthalates esters (PAEs) in water. Moreover, the adsorption performance of MIPs was evaluated by means of adsorption isotherms, kinetics and selectivity experiments. Results demonstrated that the adsorption process followed the pseudo-second-order kinetic model, with an equilibrium time of about 120 min and the equilibrium adsorption capacities of MIPs for PAEs ranging from 2.3 to 4.8 mg g−1 at 298 K. Besides, the prepared MIPs exhibited favorable selectivity and reusability for PAEs. Furthermore, an analytical method was proposed for determining trace PAEs in water samples by gas chromatography/mass spectrometry (GC/MS) combined with solid-phase extraction (SPE) using MIPs as the adsorbent. Factors that affected the extraction efficiency of PAEs were also examined and optimized. It was found that the limits of detection (LODs) and the limits of quantity (LOQs) for PAEs were 0.01–0.05 μg L−1 and 0.05–0.2 μg L−1, respectively. The spiked recoveries for PAEs were >92.9%, with the relative standard deviations (RSDs) of <3.8%. Consequently, the synthesized MIPs can serve as a promising material for the selective detection and removal of PAEs from water. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • UiO-66 with defect pores and basic N surface was prepared by mechanochemistry. • Alkaline N-coordination to UiO-66 enhanced crystal stability under basic solution. • Alkaline N compounds formed sp2 and σ-π hybridization with Zr cluster in UiO-66. • N-doped UiO-66 showed high adsorption capacity and fast diffusion for rhodamine B. • N-doped UiO-66 exhibited 558 selectivity of RhB/ST (1:1 ratio), 223 times as UiO-66. Abstract Alkaline N-compounds (pyrrole, dopamine and 2-methylimidazole) were applied to induce crystal defects on UiO-66 via mechanochemical in-situ N-doping strategy and their role on its selective adsorption for cationic dyes i.e. rhodamine B (RhB) and safranine T (ST) were investigated systematically. Alkaline N-compounds coordination were proved to simultaneously modulate pore sizes and intensify surface alkalinity of the original UiO-66. The crystal defects constructed 3-D multi-point adsorption structure, which dramatically enhanced specific adsorption for RhB and ST in binary system. Results showed that pyrrole coordinated UiO-66 possessed 30% enhancement in surface area (1549.1 m2/g) with micropores at 9 and 12 Å (larger defects in UiO-66). Furthermore, temperature programmed desorption (H 2 O and NH 3) and corrosion resistance test concluded that N-doped UiO-66 possessed improved alkali-resistance and higher alkaline surface compared to pristine UiO-66. Separation performance revealed that pyrrole-doped UiO-66 showed two times enhanced adsorption capacity for RhB (384.1 mg/g), and 223 times higher selectivity for equimolar RhB/ST than that of parent UiO-66. Textural characterization, DFT simulation and electronic factors concluded that proper defect size and alkaline surface endow the novel defective UiO-66 excellent selectivity, adsorption and recycling performances. Thus, our in-situ N-doping strategy has guiding significance to design MOFs with special and useful defects for unique selective adsorption system beyond the circle of organic dyes on industrial level. [ABSTRACT FROM AUTHOR]

[Display omitted] • The strategy for the construction of rigid & flexible COFs was proposed. • The flexible units endow COFs with abundant potential active sites. • The active sites can be released in situ through controlled dissociation reactions. • The site-released COFs exhibit significant improvement on adsorption performance. Different from traditional covalent organic frameworks (COFs) with single structural mode, COFs constructed with unique alternating rigid and flexible structural elements can maximize the great advantages of COFs in both crystalline structure and application performance. Herein, a series of rigid & flexible COFs containing both rigid and flexible units were designed and synthesized. The rigid units can reduce the growth defects and maintain the regular crystalline structures. The flexible units endow COFs with abundant potential active sites that can be released through controlled dissociation reactions. Thus, the site-released multiple-site COFs exhibit significant improvement on adsorption performance towards mercury and uranium, with a maximum adsorption capacity increase of up to 61% compared to the original COFs. The strategy for the construction of rigid & flexible COFs and the controlled release of active sites points a new direction for the design and synthesis of COFs with multi-functional sites and outstanding application performance. [ABSTRACT FROM AUTHOR]

Development of an oxygen selective adsorbent is anticipated to reduce the material and energy requirements for adsorptive separations of air by a factor of four, due to the relative concentrations of N 2 and O 2 in air, thereby decreasing the parasitic energy losses, carbon dioxide emissions, and cost of oxygen purification via pressure-swing adsorption. Here, we report that RPM3-Zn (a.k.a. Zn 2 (bpdc) 2 (bpee); bpdc = 4,4′-biphenyldicarboxylate; bpee = 1,2-bipyridylethene) is oxygen selective over nitrogen at temperatures from 77 K to 273 K, although the oxygen capacity of the sorbent decreased markedly at increasing temperatures. Due to an oxygen diffusivity that is ∼1000-fold greater than nitrogen, the effective oxygen selectivity increases to near infinity at low temperature at equal contact times due to N 2 mass transfer limitations for gate-opening. The kinetic limitation for N 2 to open the structure has a sharp temperature dependence, suggesting this effective kinetic selectivity may be “tuned in” for other flexible metal-organic-frameworks. Although the low temperature oxygen selectivity is not practical to displace cryogenic distillation, the results suggest a new mechanism for tailoring materials for kinetic selectivity, namely, capitalizing upon the delayed opening process for a particular gas relative to another. [ABSTRACT FROM AUTHOR]

[Display omitted] • Loading LDH onto biochar increased the removal efficiency for Pb(II) and Cu(II). • Mechanisms mainly involved precipitation and cation exchange. • The precipitation contribution of BC-LDH for Pb(II) was 76.26%. • The contributions of precipitation and cation exchange achieved 89.2% for Cu(II). To improve heavy metal adsorption efficiency and investigate interaction mechanisms by biochar-based materials, MgAl-layered double hydroxide (MgAl-LDH) was loaded on the coconut shell biochar (BC) obtaining the composite (BC-LDH) for adsorptive decontamination of Pb(II) and Cu(II) in water. The removal capacities of BC-LDH (294 and 38.6 mg/g) was higher than BC (13.3 and 11.4 mg/g) and LDH (126 and 22.7 mg/g) for aqueous Pb(II) and Cu(II). The interaction mechanisms between BC-LDH and heavy metals were classified as mineral precipitation, cation exchange and isomorphic replacement, electrostatic attraction, and surface complexation according to the characterization results, and the corresponding adsorption capacity were named as Q pre , Q exc , Q ele , and Q com. The quantitative analysis indicated that the contributions of the above mechanisms of BC-LDH for Pb(II) and Cu(II) followed the order of Q pre > Q ele > Q exc and Q pre > Q exc > Q ele , respectively. The Q pre values reached 76.26% and 45.0%, suggesting the mineral precipitation was the dominant mechanism. The cation exchange and isomorphic replacement (44.18% for Cu(II)), as well as the electrostatic attraction (12.46% for Pb(II)), were also key contributions to the interaction mechanisms. Compared with BC, the Q pre increased and Q ele decreased significantly, certified the combination of BC and LDH provided a kind of viable composite in heavy metal wastewater treatment. [ABSTRACT FROM AUTHOR]

Competitive adsorption and selectivity of benzene and water vapor were studied on the microporous metal organic frameworks (HKUST-1). The adsorption equilibrium and kinetics of pure component as well as binary mixtures of benzene and water vapor were systematically investigated on the HKUST-1. Their binary adsorption selectivity and permeation selectivity are predicted via the IAST method. Results showed that the equilibrium data of benzene and water vapor depicted the Langmuir–Freundlich and Dual Site Langmuir–Freundlich (DSLF) type adsorption isotherms, respectively. Benzene exhibited much higher isosteric heat and desorption activation energy than water vapor, indicating a stronger interaction with the HKUST-1. The adsorption selectivity of benzene/water on the HKUST-1 was of about ∼8.32 at 318 K and 1.0 mbar, and its diffusivity selectivity was about 17.6 at 298 K and 1.5 mbar, respectively. Breakthrough curves of benzene showed a remaining capacity of about 94.7% and 72.9% in the presence of 13 and 34 RH%. Thus, the HKUST-1 is more selective or preferential adsorption for benzene molecules in comparison to water molecules at high temperature and low pressure. Also, it shows the advantage of kinetic separation for VOCs and water vapor. [ABSTRACT FROM AUTHOR]

Abstract: A series of CeO2-doped CuCl2-KCl/MgO-γ-Al2O3 catalysts were prepared and characterized by BET, XRD, H2-TPR, FTIR-pyridine adsorption, NH3-TPD and XPS techniques. XRD, BET and TPR results show that three types of ceria species exist on the surface of catalysts: dispersed ceria, small aggregated crystalline CeO2 species and large ceria particles. It was found that copper-based catalysts modified with small aggregated crystalline ceria species exhibited higher conversion of ethane and selectivity to vinyl chloride compared to copper-based catalysts with dispersed ceria or large ceria particles. The promotional effects may be originated from the formation of large amount of surface capping oxygen species (O2 − or O−) due to structural defects and electronic properties of nonstoichimetric ceria. Moreover, these surface capping oxygen species accelerate oxidation of part of Cu+ to Cu2+, which are responsible for the increase of intermediate Cl2 species in the process of ethane oxychlorination. NH3-TPD results show that the catalysts modified with small aggregated crystalline ceria species have a large amount of weak acidic sites on the surface, and these weak acidic sites benefit dehydrochlorination of dichloroethane. The activity tests revealed that the copper-based catalyst with cerium content x =5wt.% exhibited the highest activity due to the excellent coordination effect between ceria and copper species and the largest amount of weak acid sites for breaking C–H bonds and dehydrochlorination of dichloroethane. [Copyright &y& Elsevier]

Commensurate adsorption occurs when the number of molecules adsorbed per unit cell relates to the symmetry of the framework and its topology. While rare in zeolite materials, commensurate adsorption has been observed in several MOF materials. In some MOF materials, several molecules having dimensions within a limited size range show this effect. This paper describes the commensurate adsorption properties of three MOF materials and also two MOFs showing unusual combined structure-composition adsorption features. [ABSTRACT FROM AUTHOR]

Abstract: A multifunctional three-dimensional quaternary chalcogenide [Na5Zn3.5Sn3.5S13]·6H2O has been synthesized by solvothermal reactions. [Na5Zn3.5Sn3.5S13]·6H2O represents an interesting example of metal chalcogenides that combines semiconductivity, porosity, and light emission in a single structure. It crystallizes in the cubic space group Fm-3c, a=17.8630(3)Å, V=5699.85(17)Å3, Z=8. The compound decomposes at ∼450°C. A band gap of 2.9eV is estimated from the optical diffuse reflectance data. A strong photoluminescence peak is observed at 2.43eV in Mn doped samples. The electronic and optical properties of this compound can be systematically tuned by substitution of metal and chalcogen elements. [Copyright &y& Elsevier]

• Co-adsorption of Cu(II) and TC on PE microplastics with biofilm was first studied. • Biofilm enhanced the adsorption and stabilization of Cu(II) and TC on microplastics. • Competition and complexation interactions were involved in the adsorption process. • Microplastics with biofilm act as carriers of heavy metals and antibiotics in water. In this study, the adsorption properties of Cu(II) and tetracycline (TC) onto virgin and biofilm-developed polyethylene (PE) microplastics were investigated in batch sorption experiments. PE microplastics were placed at sewage outlets (Shanghai, China) for 20 days to develop biofilm on their surface. The adsorption and desorption isotherms of Cu(II) and TC were well fitted by the Freundlich model, and revealed that biofilm could enhance the adsorption and stabilization of Cu(II) and TC on microplastics. The linearity test of the film diffusion model in kinetic experiments suggested that the adsorption on virgin and biofilm-developed microplastics was dominated by intra-particle diffusion and film diffusion, respectively. Compared with the virgin microplastics, the adsorption of Cu(II) and TC on biofilm-developed microplastics was additionally affected by pH-dependent complexation interactions in the biofilm and competition interactions. Cu(II) pre-adsorbed on the biofilm could be released into solution because of competition effects of TC. Fourier transform infrared spectroscopy (FTIR) and density functional theory (DFT) further confirmed that the enhanced adsorption of TC on the biofilm could be attributed to the complexation of TC, Cu(II) and components in biofilm. This study illustrated that biofilms could enhance the role of microplastics in the Cu(II) and TC migration by changing their adsorption properties on microplastics. [ABSTRACT FROM AUTHOR]

The accumulation of Cr(VI) will cause mutagenic and carcinogenic effects on humans. Therefore, the standard regulations have been governed by the EPA to control the chromium content in the effluent and drinking water and have made it mandatory [1]. For the better recovery of the adsorbent; Magnetic nano particle based phosphorene titanium nano tubes were used for the first time in action which has been proven to be superior for the Chormium pollutants. MNP-PN-TNT (Magnetic nanoparticle-Phosphorene-Titanium nano tubes) was synthesized from hydrothermal method in this study. The prepared material is used for effective removal of Cr(VI) from the water by adsorption technique in acidic environment. The adsorption capacity was found to be 35 mg g−1 at the initial concentration of 50 mg L−1maintainingthe temperature under 45 °C. The optimal operation condition is under pH 9, temperature of 25 °C, and dosage of 0.8 g L−1 obtained from RSM (Response Surface Methdology). The adsorption process of MNP-PN-TNT is conformed with a pseudo-second-order kinetic model. Cr(VI) adsorption behavior with MNP-PN-TNT, is spontaneous from the results of thermodynamics analysis. The adsorption mechanism of Cr(VI) with MNP-PN-TNT was evident by O1s, C1s, Cr 2p, Ti 2p, Fe 2p and P 2p of XPS. Cr(VI) is adsorbed with MNP-PN-TNT, in randomness during the adsorption process. The most attractive property of phosphorene is layered structure. The OH bonds and O bond in the surface of phosphorene are existed. In addition, a lot of activity sites support for Cr(VI) adsorption. The fantastic mechanical property supplies phosphorene an attractive 2D auxetic material. Unlabelled Image • It's a first research for Cr(VI) adsorption with MNP-PN-TNT. • The response surface methodology was used for confirmed the optimal operating conditions. • The process of Cr(VI) adsorption with MNP-PN-TNT is an endothermic reaction obtained from thermodynamics. • The adsorption mechanism of Cr(VI) with MNP-PN-TNT was via displacement of surface hydroxyl groups. [ABSTRACT FROM AUTHOR]