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[Display omitted] The tunable porous structure of metal organic frameworks (MOFs) plays a crucial role in determining their adsorption performance. In this study, we developed and employed a strategy involving monocarboxylic acid assistance to synthesize a series of zirconium-based MOFs (UiO-66-F 4) for the removal of aqueous phthalic acid esters (PAEs). The adsorption mechanisms were investigated by combining batch experiments, characterization and theoretical simulation. By adjusting the affecting factors (i.e., initial concentration, pH values, temperature, contact time and interfering substance), the adsorption behavior was confirmed as a spontaneous and exothermic chemisorption process. The Langmuir model provided a good fit, and the maximum expected adsorption capacity of di- n -butyl phthalate (DnBP) on UiO-66-F 4 (PA) was calculated to be 530.42 mg·g−1. Besides, through carrying out the molecular dynamics (MD) simulation, the multistage adsorption process in the form of DnBP clusters was revealed on a microcosmic scale. The independent gradient model (IGM) method showed the types of weak interactions of inter-fragments or between DnBP and UiO-66-F 4. Furthermore, the synthesized UiO-66-F 4 displayed excellent removal efficiency (>96 % after 5 cycles), satisfactory chemical stability and reusability in the regeneration process. Hence, the modulated UiO-66-F 4 will be regarded as a promising adsorbent for PAEs separation. This work will provide referential significance in tunable MOFs development and actual applications of PAEs removal. [ABSTRACT FROM AUTHOR]

In recent years, the XACML (eXtensible Access Control Markup Language) is widely used in a variety of research fields, especially in access control. However, when policy sets defined by the XACML become large and complex, the policy evaluation time increases significantly. In order to improve policy evaluation performance, we propose an optimization algorithm based on the DPCA (Density Peak Cluster Algorithm) to improve the clustering effect on large-scale complex policy sets. Combined with this algorithm, an efficient policy evaluation engine, named DPEngine, is proposed to speed up policy matching and reduce the policy evaluation time. We compare the policy evaluation time of DPEngine with the Sun PDP, HPEngine, XEngine and SBA-XACML. The experiment results show that (1) when the number of requests reaches 10,000, the DPEngine evaluation time on a large-scale policy set with 100,000 rules is approximately 2.23%, 3.47%, 3.67% and 4.06% of that of the Sun PDP, HPEngine, XEngine and SBA-XACML, respectively and (2) as the number of requests increases, the DPEngine evaluation time grows linearly. Compared with other policy evaluation engines, the DPEngine has the advantages of efficiency and stability. [ABSTRACT FROM AUTHOR]

Different metalheteropoly acid salt catalysts were prepared by adding different metal ions (Fe, Co, Ni), and the structure of the materials was characterised by XRD, infrared, ultraviolet, fluorescence, etc., and heteropolyacid salt (TBA)4Hx[PW11M(Q)O39]·nH2O, wherein M = (Fe, Co, Ni) with Keggin-type structure was confirmed. A series of changes in the surface of the material after the addition of metal ions can be seen by scanning electron microscopy. The stability of the material was also experimentally designed and the material showed good stability. The prepared materials were subjected to the degradation of organophosphorus followed by O,O-diethyl-S-(p-tolyl) phosphorothioate as a degradation substrate. The catalytic performance of (TBA)4[PW11Fe(H2O)O39]·2H2O was found better among all synthesised materials, it degraded completely under visible light in 90 min, and degradations performance was analysed by ion chromatography by determining the presence of PO43-. In order to explore its degradation mechanism, ammonium oxalate (AO), isopropanol (IPA) and benzoquinone (BQ) were used to quench holes (h+), hydroxyl radicals (•OH) and superoxide radicals (•O2−). It was observed that the important role in the degradation reaction is due to •OH radicals and it was also confirmed through 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) spin capture electron paramagnetic resonance (EPR) technology validates this conclusion. The prepared photocatalysts (TBA)4[PW11Fe(H2O)O39]·2H2O can be better applied to the degradation of organic phosphorus, which can reduce the environmental pollution caused by the use of organic phosphorus. [ABSTRACT FROM AUTHOR]

[Display omitted] • The novel adsorbent of UiO-66-NH 2 @Mg(OH) 2 was prepared and characterized. • The adsorption capacity was improved significantly after modification. • Adsorption behavior and mechanism of phosphate on UNM were explored. • Multiwfn wave function methods were applied to interpret the adsorption mechanisms. • Phosphate was successfully recovered by the struvite-based method. Two serious challenges of water eutrophication and phosphorus resources exhaustion make the P recovery imperative. In this work, a novel phosphate adsorbent UiO-66-NH 2 @Mg(OH) 2 (UNM) has been synthesized by the in-situ growth of magnesium hydroxide nanosheets around UiO-66-NH 2. The batch adsorption experiments were carried out by controlling the single variate (such as pH, initial concentration, contact time, temperature and interfering anions) to explore the adsorption behaviors. And the adsorption dynamics and isotherms fit well with the pseudo-second-order (PSO) and Langmuir models, combined with the thermodynamics results, indicating a spontaneous and endothermic monolayer chemisorption process. Besides, the maximum phosphate adsorption capacity of UNM was calculated as 408.07 mg/g (≈130.39 mg P/g) at pH = 6.0, T = 298 K. A series of characterizations (XRD, FT-IR, SEM, EDS, BET, TGA, XPS, ICP-MS et. al) and quantum chemical analysis methods (ESP, ALIE and Hirshfeld surface) was applied to predict the reactive sites. The possible mechanism can be deduced as two continuous steps: the physical attraction by weak interactions and the chemical adsorption with an ion-exchange mechanism. The UNM also presented high removal efficiency in the environmental water samples and showed satisfactory reusability and excellent chemical stability in the recycling process. From the desorption effluents, we successfully recycled the struvite with 14.31% P content. Therefore, the UNM will be regarded as a promising phosphate adsorbent in practice and this work will provide inspiration and guidance for the design and preparation of high-efficiency P-removal adsorbents. [ABSTRACT FROM AUTHOR]

[Display omitted] In the adsorption process of functionalized layered double hydroxide (LDH) to target pollutants it, is essential to investigate the role of functional groups. In this work, 2‑mercaptoethane sulfonic acid (MS) was used as an intercalation modifier to prepare functionalized NiFe-LDH by solvothermal method. The interfacial interaction between the functional groups and the NiFe-LDH surface was studied via molecular dynamics simulation. During the intercalation process, the more negatively charged sulfonic acid group tends to self-assemble electrostatically with the LDH laminate, while the sulfhydryl group is involved in complexing heavy metal ions. The adsorption experiments showed that the adsorption performance of the adsorbent for the three ions of Cd2+, Mn2+, and Co2+ at 298.15 K was 266.16 mg/g, 175.60 mg/g, and 106.56 mg/g, respectively, which were 10 times, 8.7 times, and 4.9 times higher than that of unmodified NiFe-LDH. Meanwhile, Multiwfn wavefunction analysis combined Visual Molecular Dynamics (VMD) was applied to analyze and visualize the reaction active sites & the interactions between MS and NiFe-LDH, and the complexation of the functional group of MS with metal ions, to insight the role of the functional groups in MS molecule, and to reveal the cause that the adsorption capacity of modified NiFe-LDH for heavy metals greatly improves from the view of atoms. [ABSTRACT FROM AUTHOR]

[Display omitted] • Defect content and particle size of MOF-808 can be tuned using iron nitrate. • The modulating MOF-808 can achieve effective removal and recovery of phosphate. • Adsorption mechanisms involve electrostatic attractions and ligand exchange. In this work, a facile and green method is applied to synthesize hydrophilic MOF-808(Zr) and modulate its defect content and particle size using different amounts of iron nitrate (denoted as F) to obtain serial XF-MOF-808 ("X" implied the dosage of used F). The development of additional adsorption sites and the fine-tune of pore and particle size based on MOF-808 significantly improved phosphate adsorption performance. In particular, the 0.5F-MOF-808 shows excellent adsorption capacity (305.5 mg/g) and rapid diffusion rate (37.51 mg/g·min0.5) for phosphate at 298 K and initial pH = 6.5, outperforming pristine MOF-808 and most previously reported adsorbents. 0.5F-MOF-808 possesses a wide pH tolerance, outstanding reusability and excellent selectivity for phosphate adsorption from simulated wastewater, verified in environmental implication and regeneration experiments. Phosphate loaded on the adsorbent can be converted to struvite for agricultural fertilizer via a simple crystallization process. Compared to MOF-808, the exceptional sorption performance of 0.5F-MOF-808 is supported by decreased internal diffusion limitation, enlarged pore size and the development of new adsorption sites, which can be proved by advanced characterizations and batch adsorption experiments. This work presents a promising modification strategy of MOF materials for phosphate adsorption and recovery. [ABSTRACT FROM AUTHOR]

The wide clinical application of d -penicillamine (D-PA) makes it inevitably accumulates in the environment, seriously threatening human health and the ecological environment. To better supervisory control D-PA, a highly sensitive and reliable photoelectrochemical (PEC) sensor based on gold nanoparticles (Au NPs) loaded on graphitic carbon nitride sheet and hexagonal NH 2 -UiO-66 composite (g-C 3 N 4 /Au/NH 2 -UiO-66) was synthesized. Tactfully using the strong bonding between D-PA and Au NPs and the effective carrier separation of Z-scheme heterojunction, the designed g-C 3 N 4 /Au/NH 2 -UiO-66 PEC sensor without an extra recognition unit exhibited a selective and sensitive photocurrent to D-PA. With the aid of UV diffuse reflectance spectra (UV-DRs), electron paramagnetic resonance (EPR) characterization, and free radical capture experiments, the electron transfer path of the PEC sensing system was deduced. The proposed g-C 3 N 4 /Au/NH 2 -UiO-66 PEC-based sensor achieved a low detection limit of 0.0046 μM (S/N = 3) with a wide linear response ranging from 10 nM to 400 μM. In addition, its good stability and selectivity also laid a good foundation for practical applications. [Display omitted] • A d -penicillamine PEC sensor without extra recognition unit was constructed. • The Z-scheme greatly promoted the separation of photogenerated carriers. • The electron transport path and detection mechanism was explored. • The wide linear range and low detection limit for d -penicillamine was achieved. [ABSTRACT FROM AUTHOR]