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Abstract: Hollow fiber renewal liquid membrane (HFRLM), a new liquid membrane technique inspired from surface renewal theory, is used to simultaneously remove and recover copper from acidic wastewater. The commercial extractant, LIX984N, is used as a carrier in liquid membrane phase, kerosene used as a diluent. CuSO4 solutions is used to simulate acidic industrial wastewater, in which the pH is adjusted by dilute H2SO4. The mass transfer mechanisms of the process are investigated. As a carrier-facilitated transport process, the addition of LIX984N in the liquid membrane phase can greatly improve the transport performance; the organic/aqueous stripping volume ratio from 1:10 to 1:7 on lumen side mixture is better in terms of the renewal effect and diffusion resistance. The higher pH in the feed phase (>3) and H2SO4 concentration in the stripping phase around 2.0molL−1 are favorable for the transport process due to the increase of mass transfer driving forces. The mass transfer fluxes increase with increasing flow rates on two sides. The countercurrent cascade experiments show that the HFRLM process could carry out the simultaneous removal and recovery of copper from wastewater successfully. The modeled results based on the surface renewal theory demonstrate a good agreement with experimental data. [Copyright &y& Elsevier]

Abstract: The facilitated transport of Cr(VI) through a bulk liquid membrane (BLM) is investigated, using the commercially available solvent tri-n-butyl phosphate (TBP) as mobile carrier. The influences of the carrier concentration in the liquid membrane phase, the HCl concentration of the feed phase, and the stripping concentration on the mass transfer process are studied. The transport rate of Cr(VI) increases with increasing the TBP concentration and HCl concentration. The increasing of the stripping concentration improves the stripping process until a plateau is reached. A kinetic model is used to describe the Cr(VI) transport behavior, assuming that it obeys the kinetic laws of two consecutive irreversible first-order reactions. The experimental data fits reasonable well with the derived model. The analysis of the accumulation of Cr(VI) in the liquid membrane phase and the discussion of the rate-controlling step under different experimental conditions are carried out. The magnitude of the value of k e and k s is found to be 10−4–10−5 s−1, and is well in agreement with other studies. [Copyright &y& Elsevier]

Abstract: A new liquid membrane technique, hollow fiber renewal liquid membrane (HFRLM), is used for simultaneous extracting and concentrating citric acid from dilute solutions. The organic phase of 30% N235+20% n-octanol+50% kerosene was used as liquid membrane phase, NaOH as stripping phase. Experiments were performed as a function of operation mode, carrier concentration in the organic phase, initial citric acid concentration in the feed phase, NaOH concentration in the stripping phase, etc. The results showed that the HFRLM process was very stable. The transport of citric acid from membrane phase to the stripping phase was the rate-controlling step for this process. The stirred mixture of the stripping phase and the organic phase flowed through the lumen side of the module could provide a higher mass transfer rate. The transport studies with a recycling experiment indicated that HFRLM was a promising recovery method for separation and concentration of compounds from dilute solutions. [Copyright &y& Elsevier]

[Display omitted] • Acetic acid is a modulator to control the defect degree in UiO-66-(OH) 2. • UiO-66-(OH) 2 -AA-20 exhibits an adsorption amount of 891.1 mg g−1 for borate ion. • Experimental analysis and theoretical calculations were used to study the adsorption mechanism. Developing high-efficiency adsorbents for borate ion still remains up to now. Herein, a facile and green method is used to obtain serial hydroxyl functionalized UiO-66-(OH) 2 -AA-X (AA, acetic acid; X, AA usage) by using AA as a modulator. The addition of AA can induce the generation of defect units in the adsorbents due to its partial substitution for the organic linkers. It is found that the defect degree as well as the porosity can be neatly regulated by the AA amount. In particular, UiO-66-(OH) 2 -AA-20 with the most defects exhibits a high adsorption capacity (891.1 mg g−1) towards borate ion, outperforming the most previously reported adsorbents. The adsorption reaches equilibrium at 600 min. The adsorption behavior can be well described by the Langmuir isotherm model and pseudo-second-order model. Besides, UiO-66-(OH) 2 -AA-20 possesses a wide pH (3–10) tolerance, excellent anti-interference ability, and good reusability. A combination of experimental characterization and density functional theory calculation indicates the free hydroxyl groups serve as the main adsorption sites, and the adsorption-driven forces involve electrostatic, coordination, hydrogen bonds and π–π stacking interactions. On these basis, our work may provide a guideline for constructing high-efficiency defective adsorbents for borate ions via a modulated strategy. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A stable silicon-supported copper catalyst was synthesized using Cu-NH 3 complexes. • CuNSi/sulfite system is proposed as a promising system of SO 4 −-based AOPs. • Neutral pH favors the activation of sulfite on CuNSi surface for SO 4 − generation. • Oxidation of As(III) by CuNSi/sulfite system was achieved and optimized. • Possible mechanisms for the oxidation of As(III) were identified. Abstract Sulfite activation by metal is a promising SO 4 −-based advanced oxidation process (SR-AOPs) for pollutant removal. Homogeneous systems are limited by strict working pH and metallic oxide sludge generation. To overcome these drawbacks, a copper–silica composite modified by ammonia (CuNSi) was synthesized through a complexation–adsorption–combustion method and characterized by X-ray diffraction, X-ray photoelectron spectroscopies, transmission electronic microscopy etc. CuNSi demonstrates a stable and remarkable catalytic activation of sulfite for As(III) oxidation after five reuses in neutral wastewater. The negligible oxidation of As(III) under anoxic condition confirmed the importance of oxygen for the CuNSi/sulfite system. Bicarbonate significantly inhibited As(III) oxidation, whereas Cl− and NO 3 − slight restrained As(III) oxidation. The dosage of sulfite and As(III) affected initial rates of As(III) oxidation via the equation r 0 = k r × [Sulfite]2.11 × [As(III)]0.33 (k r = (3.68 ± 0.46) × 103 M−1.44 min−1). The apparent activation energy for As(III) oxidation was 60.14 ± 5.17 kJ mol−1. The SO 4 − was confirmed as the primary oxidative species, and the sulfite activation by CuNSi was through a Cu(II)–Cu(I)–Cu(II) cycle. Overall, this study suggests that the CuNSi/sulfite system can be a promising AOP for further application in wastewater treatment. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Metals oxides doped Na 2 CO 3 fibers were prepared via ultrasonic atomization method. • Breakthrough (<1ppm) time of the Cu doped sorbent increased from 2 h to 6.5 h. • Cu doped sorbent showed high HCl selectivity with much low HCl/CO 2 ratio (1:25 v/v). • Cu doping strongly promotes the reactivity of Na 2 CO 3 fibers and HCl at 150 °C. • The sorbents could maintain stable cyclic performance after three regenerations. Abstract A novel inexpensive metal oxides doped sorbents had been investigated for selective capture of hydrogen chloride (HCl) from HCl/CO 2 (1:25 v/v) mixture gas at 150 °C. In this work, metals oxides (Fe, Mn, Ce and Cu) grains supported on the Na 2 CO 3 fibers were firstly prepared via ultrasonic atomization loading method, respectively. The results of HCl removal experiments showed that Cu dopant with optimal content synergistically facilitated HCl capture performance, continuously removing HCl from initial content of 1% to less than 1 ppm as long as 6.5 h. And the HCl capacity reached 3.15 mmol/g, corresponding to the conversion of active component Na 2 CO 3 was up to 0.89. Meanwhile, the Cu doped sorbent exhibited a strongly selective adsorption of HCl under extreme lower volume ratio HCl/CO 2 of 1:25. The enhancement of Na 2 CO 3 reactive activity depended on the highly dispersed copper oxides nanoparticles on the surface of Na 2 CO 3 fibers. CuO species in copper oxides reacted with HCl to form CuCl 2 , while the presence of amorphous phase connecting CuO nanoparticles and Na 2 CO 3 strongly promoted the mass transfer in product layers. The intensification of these two aspects made copper doped adsorbent exhibited significant HCl removal performance. Moreover, during regeneration test, the sorbents could maintain fairly stable cyclic performance within three cycles. [ABSTRACT FROM AUTHOR]

• The difference of ion–dipole interaction was studied to illustrate the phase separation behavior. • Relative dielectric constant and E T (30) to water were proposed as rapid method of CPCAs development. • The CO 2 cyclic capacity of CPCA composed of MEA + 1,4-dioxane + H 2 O was 49.0% higher than that of 30 wt % MEA. CO 2 phase change absorbents, CPCAs, have attracted growing interest due to their potential of energy saving for CO 2 capture. Unclear phase separation pattern is challenging for the efficient development of CPCAs. The effect of organic solvents properties on the phase separation process was investigated in this work. The difference of ion–dipole interaction between ion-organic solvent and ion-water was used to illustrate the phase separation behavior. Relative dielectric constant and E T (30) to water were proposed as indicators to provide guidance on the selection of organic solvents in CPCA. The organic solvents with less dielectric constant and E T (30) relative to water, were tend to phase split, and higher ion distribution coefficient obtained. The developed MEA CPCAs showed larger CO 2 cyclic capacity than 30 wt. %MEA, among which 1,4-dioxane CPCA was 49.0% higher than benchmark MEA solution. [ABSTRACT FROM AUTHOR]

A better conversion enhancement of esterification between acetic acid and n-butanol was achieved in a catalytically active membrane reactor ( p CAMR) when compared to that in a traditional inert membrane reactor (IMR). This enhancement was attributed to a novel composite catalytically active membrane in which a highly porous catalytic layer was introduced. SEM images showed that the membrane consisted of three layers: the top layer was a highly porous catalytic layer with massive macrovoids and “sponge-like” pores, the middle layer was a dense polyvinyl alcohol selective layer, and the bottom layer was a porous polyethersulfone support layer. The preparation of a highly porous catalytic layer instead of a dense one in the composite membrane greatly decreased the overall mass transfer resistance of the reactor from 6.7 × 10 5 to 5.6 × 10 5 s/m, a value which is even comparable to that of IMR (5.1 × 10 5 s/m) where the additional catalytic layer was absent. The effects of operational parameters on the esterification-pervaporation coupling performance in p CAMR were systematically evaluated. Through a reasonable match between reaction rate and water removal rate, a genuine in-situ water removal at a molecular lever was realized. For comparison, coupling performances in an IMR and a catalytically active membrane reactor with a dense composite membrane ( d CAMR) were also investigated. Results showed that the coupling performance in p CAMR outperformed both IMR and d CAMR due to a combination of much lower overall mass transfer resistance and higher mass transfer driving force for water removal in p CAMR. After 45 h at 85 °C, the acid conversion in p CAMR reached almost completion, an approximately 43% of conversion enhancement was achieved when compared to equilibrium conversion. [ABSTRACT FROM AUTHOR]

Glycerol ketals are often considered as important bio-based diesel additives or perfume substances which could be synthesized from the acetalization of glycerol and cyclohexanone, however, acetalization is a typical example of reactions controlled by thermodynamic equilibrium. In this study, a catalytically active membrane was prepared by immersion phase inversion and was used for the conversion enhancement of present reaction by continuous removal of by-product water in a pervaporation membrane reactor. SEM images showed that a highly porous “sponge-like” catalytic layer immobilized with catalyst Zr(SO 4 ) 2 ·4H 2 O was uniformly coated on a polyvinyl alcohol/polyethersulfone pervaporation membrane. Synthesis performances in batch reactor, inert membrane reactor and catalytically active membrane reactor were compared, showing that no equilibrium limitation for glycerol conversion was observed in both the inert membrane reactor and catalytically active membrane reactor. The effect of various operational parameters on the synthesis performance in the catalytically active membrane reactor were investigated, showing that higher temperature and A/V ratio favored better enhancement in glycerol conversion since an acceleration of water removal rate was induced. Optimal catalyst loading and initial mole ratio was also determined for better synthesis performance. Under optimized conditions, the glycerol conversion reached 93% and a conversion enhancement of approximately 52% was achieved when compared to equilibrium conversion at 75 °C. [ABSTRACT FROM AUTHOR]

• A biodegradable bionic "butterfly effect" nanoreactor for remodeling tumor microenvironment. • The synthesis of nanoreactor was green and safe. • The reactive oxygen species control the occurrence of metal ion therapy. • A triple interlocked combination of starvation/ chemo/ metal ion therapy completely ablates of solid tumors. Tumor microenvironment has been used as the driving force of nano-therapy systems. However, due to its own complexity and heterogeneity, the therapeutic effects of many systems are still hindered by inherent cellular barriers. Herein, we designed a biodegradable nanoreactor showing interlocking "butterfly effect", which reconstructed the tumor microenvironment (TME) by functional "butterfly" and initiated the next cascade reaction to enhance the efficacy. The silver nanocubes (Ag NCs) as the core, then loading polydopamine (PDA), glucose oxidase (GOx), and tirapazamine (TPZ), which was further disguised by tumor cytomembrane to construct as a bionic nanoreactor Ag@PDA/GOx/TPZ@M (APGTM). When the nanoreactors were homologously targeted to the tumor site, GOx as the "butterfly" caused the tumor cells entering starvation state by consuming glucose and O 2 and generating gluconate and H 2 O 2. Furtherly, the generated hypoxia state activated TPZ to achieve chemotherapy, and the non-toxic Ag NCs were degraded into toxic Ag+ under high H 2 O 2 levels to carry out metal ions therapy. This "butterfly effect" of nanoreactor launching a triplet chain reaction can solve the problem of the lack of reciprocity on multi-modal therapy by reshaped the TME, which opens a new way for accurate and effective tumor cell ablation. [ABSTRACT FROM AUTHOR]

• Optimum conditions for HCl selective removal over CuO x /Na 2 CO 3 sorbent were studied. • The diffusion coefficient in product layer was calculated according to RPM model. • According to the model, breakthrough time can be accurately predicted (error <4%). • 500t sorbents may be used to clean the blast furnace gas (400000 m3/h) up to 13 days. Selective removal of hydrogen chloride (HCl) using porous active sorbents has been considered to be a feasible way to reduce the harm of chlorine in flue gas. In this work, the kinetics process of HCl capture from CO 2 -rich mixture gases by CuO x /Na 2 CO 3 porous supported sorbent was studied systematically in a fixed-bed column at low temperature. The effects of flow rate, gas composition and operation temperature on HCl adsorption were intensively investigated. The results show that the HCl adsorption performance of sorbents decreased with the feed flow rate and CO 2 content increasing, whereas the effect of HCl concentration was negligible. In addition, HCl adsorption capacity increased with the increase of temperature (100–150 °C), but decreased after 170 °C. In the first part of dynamic heterogeneous reaction, axial dispersion mass transfer of reactive gas molecules dominated the overall reaction rate. But for second part, the gas diffusion in product layers replaced as a rate-controlled step. The overall sorbents conversion calculated by random pore model (RPM) demonstrated fine agreement with the experimental data and the diffusion activation energy was 23.11 kJ/mol. Moreover, the semi-empirical equation of BDST model was applied to predict the breakthrough curves with a standard deviation less than 4%. The forecasting results of industrial large-scale reactor indicate that 500 tons sorbents can effectively remove HCl from the flue gas (400000 m3/h) produced by 2650 m3 blast furnace for as long as 13 days. [ABSTRACT FROM AUTHOR]