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A more efficient, economical and environmentally friendly process which combines with organic synthesis, electrochemical reduction and electrodialysis technology to produce high quality N-acetyl-L-cysteine. [Display omitted] • A novel green process to produce high quality NAC was developed. • The NAC preparation process combines electrochemical synthesis with electrodialysis technology, using the carbon electrode. • The novel process improved production efficiency and reduced energy consumption and production cost. • The novel process significantly reduced the quantity of organic solvents consumption and wastes discharge, which is environmentally friendly. N-acetyl-L-cysteine (NAC) is widely used in the biochemistry, pharmaceuticals and food additives. At present, the synthesis methods of NAC are difficult to achieve high-quality NAC production due to multi-step separation, poor product quality and heavy pollution. In this study, a new green process was developed combined with organic synthesis, electrochemical reduction and electrodialysis technology to efficiently produce high quality NAC. This new process adopted the strategy of acylation followed by electrolysis. Firstly, L-cystine was acetylated to N, N'-diacetyl-L-cystine (DiNAC), and then DiNAC was electrochemically directly reduced to NAC using carbon cathode. Finally, the high quality NAC was extracted after desalting by electrodialysis. The novel preparation process avoids racemization and oxidation of intermediate products, achieves the removal of impurities, desalting and recycling of electrolyte, and largely reduces wastes discharge. The pilot scale test showed that the total yield was 73.1%, the electrochemical yield was 96.2%, and the energy consumption was 2.56 kW·h kg−1. The brief environmental and tech-economic analysis demonstrated that the process had the advantages of mild reaction conditions, short synthesis steps, high product quality, low waste emissions. It indicates that this novel process is efficient, economical, environmentally friendly, and suitable for the industrial production. [ABSTRACT FROM AUTHOR]

[Display omitted] • One-step synthesis of Ox-nZVI was highly efficient for aqueous Pb(II) removal. • Mechanisms of Pb(II) removal were reduction, adsorption and co-precipitation. • Oxalate promoted Pb(II) reduction by capturing electrons from nZVI core. • Pb(II) adsorption best fitted with pseudo-second-order and Langmuir models. • Oxalate participated in electrostatic attraction and substitution with Pb(II). A novel oxalated zero-valent iron nanoparticle (Ox-nZVI) was synthesized using one-step and two-step modification to investigate the performance and synergistic mechanisms for aqueous Pb(II) removal. Batch experiments showed the maximum removal capacity of Ox-nZVI toward Pb(II) reached 527 mg/g along with 7.87 mg/g Fe release (R2 = 0.989) at a pH of 7.0, contact time of 1440 min, initial Pb(II) concentration of 250 mg/L and temperature at 25 °C. The characterization results suggested reduction, adsorption and co-precipitation were synergistically realized between Pb(II) and Ox-nZVI. Oxalate modification favored steric stability by coverage of membrane-like flakes on the outer surface of nanospheres, leading to more Pb(II) reduced to Pb0 by capturing electrons from the oxidation of Fe0 into iron oxides including Fe 3 O 4 , Fe 2 O 3 and FeOOH. The Pb(II) complexes existed on the active sites of Ox-nZVI surface via Fe C 2 O 4 - , Fe OOH and Fe OH groups. The adsorption process was best fitted with pseudo-second-order kinetic model and Langmuir isotherm through surface mass transfer and interparticle diffusion. The existence of PbO, Pb 3 (CO 3) 2 (OH) 2 and PbFe 12 O 19 was attributed to the co-precipitation of Pb(II) with hydroxyl ion and atmospheric CO 2. This study provided a promising iron-based nanomaterial with surface modification strategy for effective and long-term treatment of Pb(II) from aqueous environment. [ABSTRACT FROM AUTHOR]

• The micro-chemical environments of TaS 2 laminates were modified for acid recovery. • Positively charged polymers were inserted into TaS 2 channels. • The modified TaS 2 membranes show improving acid fluxes and separation factors synergistically. • The next generation acid recovery membranes were successfully established. Two dimensional (2D) TaS 2 laminates have highly regular and ordered transfer mass channels, thus being promising acid recovery membrane candidates for diffusion dialysis (DD) applications to discern H+ and metallic ions. However, it remains a daunting task to get access to high-performance 2D acid recycling membranes made from single TaS 2 nanosheets. Here, we report manipulation of the chemical environments of TaS 2 channels to develop excellent acid recycling 2D membranes. As demonstration projects, positively charged poly(diallyldimethylammonium chloride) (PDDA) and poly(4-vinylpyridine) (P4VP) in acid solution were chosen as polycation intercalators to modify the TaS 2 2D channels. Under the DD mode, the TaS 2 membrane exhibits a H+ dialysis coefficient (U H +) of 3.72 × 10−3 m h−1 and separation factor (S) of 9 towards the simulated acid pickle. In contrast, the U H + and S value of the PDDA@TaS 2 membrane improve to 12.7 × 10−3 m h−1 and 34.4 respectively. Those of the P4VP@TaS 2 membrane increase to 12.5 × 10−3 m h−1 and 29.1 respectively. The reported acid recovery properties of PDDA@TaS 2 and P4VP@TaS 2 membranes exceed the commercial DF-120 acid recovery membranes. The experiment and simulation results reveal that the synergistical enhancements of U H + and S originate from the incorporating polycations in PDDA@TaS 2 and P4VP@TaS 2 composite channels. [ABSTRACT FROM AUTHOR]

[Display omitted] • • Zn ion-modulated polyamide membrane was fabricated by interfacial polymerization. • • Zn element was uniformly distributed in the coordination network. • • The introduction of Zn ion enhanced CO 2 -facilitated transport effect of membrane. Polyamide membrane, fabricated via interfacial polymerization process, is a typical class of facilitated transport membrane for CO 2 separation with amino groups serving as reactive CO 2 carriers. Herein, to further enhance the CO 2 -facilitated transport effect of polyamide membrane, Zn(NO 3) 2 is directly introduced into aqueous triethylenetetramine phase for constructing Zn-N coordination polyamide membrane taking advantage of the coordination interaction between Zn ions and amino groups from triethylenetetramine. The good solubility of Zn(NO 3) 2 in aqueous amine solution and moderate coordinative ability of Zn ions are beneficial to a uniform distribution of Zn in polyamide layer. The coordination of N from triethylenetetramine monomer to Zn ion centre produces more tertiary amino groups and free amino groups with stronger affinity to CO 2 in Zn-N coordination membrane for enhancing the facilitated transport effect. Additionally, the Zn-N coordination interaction generates smoother surface of membranes when sufficient Zn ions are introduced. The membrane with 0.1 wt% of Zn ions in aqueous phase exhibits the highest CO 2 /N 2 and CO 2 /CH 4 selectivity of 106.7 and 55.2, which increase, respectively, by 75.2% and 99.3% without compromising CO 2 permeance in contrast with pristine polyamide membrane. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mg doping greatly increases the action sites of monometallic-centered MIL-101(Fe). • Construction of bis-MIL composite MOM tunes the structure and enhances the properties. • The maximum sorption capacity of MOM towards Pb(II) is 320.941 mg·g−1. • MOM has good resistance to salt interferences and regeneration performance. MIL-101(Fe) has received more and more attention in wastewater treatment, and how to further improve its stability and sorption capacity has become a research focus. In this study, metal Mg was used to dope MIL-101(Fe) to construct Mg@MIL-101(Fe) with bimetallic sites, which was then mixed with NH 2 -MIL-125(Ti) to successfully fabricate Mg@MIL-101(Fe)/NH 2 -MIL-125(Ti) (MOM) bis-MIL composites. MOM not only contains a large number of sorption sites but also exhibits excellent stability and reusability, realizing efficient sorption of Pb(II) from aqueous solution. In addition, the sorption performance and mechanism of Pb(II) on MOM were investigated by the characterizations of SEM, BET, TG, XRD, FTIR and XPS, as well as the kinetic and thermodynamic analyses. The sorption of Pb(II) on MOM is in accordance with the Langmuir isothermal model and pseudo-second-order kinetic model. The maximum sorption capacity of Pb(II) on MOM derived from the Langmuir model fitting is 320.941 mg·g−1. The sorption of Pb(II) on MOM is strongly affected by pH, but not by ionic strength, which indicates that MOM has good resistance to salt interferences. The strong complexation of carboxyl, hydroxyl and amino functional groups with Pb(II) is the main sorption mechanism of Pb(II) on MOM, and electrostatic interaction and ion exchange also contribute to the sorption. In conclusion, MOM has strong practical application prospects in the treatment of Pb(II)-containing wastewater. [ABSTRACT FROM AUTHOR]

• A series of chitosan-derived ultramicroporous carbons were prepared using activating reagents-free method. • CNC-700 possesses excellent C 2 H 4 /C 2 H 6 molecular sieving performance. • High purity of C 2 H 4 can be produced via one-step adsorption–desorption process. • The good stability and scalability make CNC-700 a promising adsorbent for industrial applications. The selective separation of C 2 H 4 /C 2 H 6 pair is of paramount importance in the petrochemical industry, which is yet challenged by their similar polarities, shapes, and kinetic diameters. The use of carbonaceous adsorbents with molecular sieving capability holds great promise in achieving the desired selectivity and economically feasibility. However, such progress has been hindered by the typically wide pore size distribution observed in traditional carbons. Herein, we report a series of chitosan-based ultramicroporous carbons with C 2 H 4 /C 2 H 6 molecular sieving performance through an activating reagents-free method. The hydrothermal process of chitosan was initially employed to prepare condensed carbonaceous hydrochar rich in heteroatoms. The subsequent thermal etching led to the formation of sieving-based ultramicropores, stemming from the decomposition of heteroatoms and hot-shrinkage of pores at high temperature. The as-synthesized optimal CNC-700 sample achieved a high C 2 H 4 uptake of 32.3 cm3 (STP) g−1 and negligible C 2 H 6 adsorption at 298 K and 1.0 bar. The isosteric heat of C 2 H 4 on CNC-700 reached 34.5 kJ mol−1, significantly lower than other thermodynamically driven carbonaceous adsorbents. The fixed-bed breakthrough experiments further validated the efficient separation of equimolar C 2 H 4 /C 2 H 6 mixture under dynamic conditions. This work provides an important guideline to fabricate carbons with adjustable ultramicropore size derived from biomass for the highly effective separation of light hydrocarbons via molecular sieving. [ABSTRACT FROM AUTHOR]

• Nanosized polyethyleneimine functionalized ZIF-8 was introduced into Pebax. • PEI-ZIF-8 improved the interfacial compatibility and facilitated CO 2 transport. • PEI-ZIF-8 enhanced the CO 2 permeance and CO 2 /N 2 selectivity. Poor interfacial compatibility that often led to low gas separation performance is one of key challenges for developing composite membranes. In the present study, nanosized polyethyleneimine (PEI) functionalized ZIF-8 (PEI-ZIF-8) with good dispersion, having a particle size around 15 nm, has been synthesized via in-situ method and used as filler to fabricate Pebax/PEI-ZIF-8 composite membranes. Excluding the intrinsic porous structure and higher affinity with CO 2 of PEI-ZIF-8 beneficial for CO 2 selective transport, the large density of amine groups on PEI chains provide a good interfacial compatibility, and introduce facilitated CO 2 transport path. Furthermore, PEI-ZIF-8 reduces the crystallinity of Pebax matrix, which is favorable for CO 2 transport. The composite membrane with 5 wt% PEI-ZIF-8 shows a CO 2 permeance of 13.0 GPU with a CO 2 /N 2 selectivity of 49.0, which increases by 80.6% and 118.8% respectively in contrast with pristine Pebax membrane. The results demonstrate that nanoparticles functionalized by amine-polymer with long chains is effective for constructing composite membranes with good interfacial compatibility. [ABSTRACT FROM AUTHOR]

[Display omitted] • A three-stage recovery process was established based on BP's reductant property to achieve efficient metals recovery from spent catalysts leaching liquor. • The recovery efficiency of Pd reached 99.36 ± 0.08 % after 4 min tests with a recovery capacity of 1426.11 ± 1.73 mg Pd g−1 BP. • The overall recovery efficiency of Pt2+ was 98.62 % (467.91 mg Pt g−1 BP) after 34 min tests. • In-situ synthesized Pd/Pt-BP catalysts exhibited long-term durability of 225 h (10 mA cm−2) and reached maximum durability over 400 h. The reserves of palladium (Pd) and platinum (Pt) are scarce and require sophisticated processing. Herein, a three-stage recovery process with black phosphorus (BP) is established in this study to recover Pd and Pt from spent catalysts, presenting a promising strategy for addressing the precious metals crisis. The recovery efficiency of Pd is 99.36 % ± 0.08 % after two stages, with a total recovery capacity of 1426.11 ± 1.73 mg Pd g−1 BP, which is 90 times higher than that of the latest technologies. The overall recovery efficiency of Pt (II) is 98.62 % (467.91 mg Pt g−1 BP) after the third stage (45 °C, 30 min). Furthermore, the current density of the optimal catalysts generated in the first stage (weight ratio: Pd:Pt = 4.9:1) is the highest (57.61 mA cm−1; overpotential = 70 mV vs. RHE) among the catalysts generated in the second (Pd:Pt = 1:1) and third (Pd:Pt = 1:11) stages. Pd/Pt–BP generated in the first stage further achieved remarkable long-term stability of 225 h (10 mA cm−2) and exhibited maximum durability of > 400 h. Owing to the reduced capability and activation of BP to metals, immobilized Pd (II) and Pt (II) are recovered and directly converted to long-term stable hydrogen evolution catalysts without complex processing. [ABSTRACT FROM AUTHOR]

• An improved reactive pressure-swing distillation process for separating DMC/MeOH mixture is proposed. • The proposed process shows better energy, economic and environmental performance. • The proposed process can co-produce propylene glycol methyl ether simultaneously. Pressure-swing distillation (PSD) is a widely used in the chemical industry to separate azeotropes without the introduction of a any third component; however, the process involves high energy consumption and operating costs are required owing to the change in pressure. For the separation of methanol–dimethyl carbonate azeotropes, an intensified reactive pressure-swing distillation (R-PSD) process has been proposed, wherein a reactive distillation column is used, instead of a high-pressure column, and the propylene oxide (PO) is introduced into the system as a reactant to react s with methonal. To compare the feasibility of the proposed R-PSD process with the conventional heat-integrated PSD process, three indicators—total energy requirements, total annual cost, and CO 2 emissions—were used. The results show that the R-PSD process performs better than the conventional heat-integrated PSD process in terms of energy, economics and environmental owing to the partial consumption of methanol and the simultaneous co-production of high-value propylene glycol methyl ether (PGME). Moreover, at 50% methanol consumption, the total energy consumption, total annual cost, and the CO 2 emissions were reduced by 46.0%, 34.3%, and 45.0%, respectively, compared with the conventional heat-integrated PSD process. This implies the improved R-PSD process has significant energy-saving potential. [ABSTRACT FROM AUTHOR]