Green Chemical Engineering最新文献

Dissolution of lithium cobalt oxide (LCO) is the key step for the recovery of valuable metals (e.g., Co and Li) from spent LCO-based lithium-ion batteries (LIBs). However, the dissolution process of LCO either needs toxic solvents, and high temperature, or shows low efficiency. Deep eutectic solvents (DESs) are potential green solvents to dissolve LCO. Here, DESs with polyethylene glycol (PEG) as hydrogen bond acceptor and ascorbic acid (AA) as hydrogen bond donor are found to dissolve LCO with 84.2% Co leaching efficiency at 80 ^oC and 72 h, which is higher than that from the reported references by common DESs. Furthermore, both DESs components (i.e., PEG and AA) are cheap, biodegradable, and biocompatible. AA could be easily and abundantly extracted from natural fruits or vegetables. It provides a new guide for the green, mild, and efficient dissolution of LCO aiming at sustainable recovery of spent LIBs.

A new ultra-long chain monounsaturated 4-(N-nervonicamidopropyl-N,N-dimethylammonium) butane sulfonate (NDAS) zwitterionic surfactant with ultralow interfacial tensions was developed through the modification of nervonic acid derived from renewable non-edible seed oils by a simple and effective method. Its structure was characterized by ESI-HRMS, ¹H NMR, and ¹³C NMR. NDAS surfactant exhibited a strong interfacial activity (∼10⁻⁴ mN/m) between the crude oil and the formation brine at a very low surfactant dosage (0.05 g/L) and at high salinity conditions, which is equivalent to 2% (w/w) of dosage of the most traditional surfactants used in the enhanced oil recovery field. Meanwhile, at a very low concentration (0.05 g/L), NDAS demonstrated strong NaCl compatibility up to 100 g/L, Ca²⁺ ions compatibility up to 200 mg/L, and temperature stability up to 90 °C. The surface tension, emulsification, and biodegradability parameters were also evaluated. This work consolidates our hypothesis that increasing the hydrophobic chain length of a surfactant certainly contributes to the high interfacial activity and good compatibility of salts and temperatures. Hence, it will facilitate the design of a sustainable alternative to petroleum-based chemicals to develop bio-based surfactants and extend the domain of bio-based surfactants to new applications such as in enhanced oil recovery (EOR).

Recently, the continuous tube-in-tube reactor based on the Teflon AF membrane is emerging as a powerful toolkit for accelerating gas-liquid mass transfer and reaction rate. Because of its large gas-liquid interfacial area and short mass transfer distance, the reactor can allow a fast gas-liquid mass transfer without direct contact between gas and liquid phases, offering an efficient and safe platform for implementing gas-liquid reaction and rapid determination of gas-liquid parameters. In this review, a detailed description and construction method of this reactor are provided. Then, the recent advancements of the tube-in-tube reactor in fundamental studies and practical applications in gas-involved chemical reactions and biosynthetic processes are discussed. Finally, a perspective on future potential applications of such flow reactors is provided.

Image guided photodynamic therapy (PDT) combines fluorescence tracing and phototherapy, which can achieve a more accurate and effective treatment effect. However, traditional photosensitizers are limited by the aggregation-caused fluorescence quenching (ACQ) effect and low reactive oxygen species (ROS) generation in a hypoxic environment, resulting in poor imaging and treatment effect. Herein, we report a tricyano-methylene-pyridine (TCM)-based Type I aggregation-induced emission (AIE) photosensitizer (TCM-MBP), the strong electron acceptance (D-A) effect extends the wavelength to near-infrared (NIR) region to reduce the autofluorescence interference, and oxygen atoms provide lone pair electrons to enhance the inter system crossing (ISC) rate, thereby promoting the generation of more triplet states to produce ROS. The AIE photosensitizer TCM-MBP exhibited low oxygen dependence, NIR emission, and higher ROS production compared to commercially available Ce 6 and RB. After encapsulation with DSPE-PEG₂₀₀₀, TCM-MBP nanoparticles (TCM-MBP NPs) could penetrate to visualize cells and efficiently kill cancer cells upon light irradiation. This study provides an oxygen-independent AIE photosensitizer, which has great potential to replace the commercial ACQ photosensitizers.

Antibiotic pollution in aqueous solutions seriously endangers the natural environment and public health. In this work, Mo-doped transition metal FeCo–Se metal aerogels (MAs) were investigated as bifunctional catalysts for the removal of sulfamethazine (SMT) in solution. The optimal Mo_0.3Fe₁Co₃–Se catalyst can remove 97.7% of SMT within 60 min (SMT content: 10 mg/L, current intensity: 10 mA/cm²). The unique porous cross-linked structure of aerogel confered the catalyst sufficient active sites and efficient mass transfer channels. For the anode, Mo_0.3Fe₁Co₃–Se MAs exhibits superior oxygen evolution reaction (OER) property, with an overpotential of only 235 mV (10 mA/cm²). Compared with Fe₁Co₃ MAs or Mo_0.3Fe₁Co₃ MAs, density functional theory (DFT) demonstrated that the better catalytic capacity of Mo_0.3Fe₁Co₃–Se MAs is attributed to the doping of Mo species and selenization lowers the energy barrier for the ∗OOH to O₂ step in the OER process. Excellent OER performance ensures the self-oxygenation in this system, avoiding the addition of air or oxygen in the traditional electro-Fenton process. For the cathode, Mo doping can lead to the lattice contraction and metallic character of CoSe₂, which is beneficial to accelerate electron transfer. The adjacent Co active sites effectively adsorb ∗OOH and inhibit the breakage of the O–O bond. Rotating ring disk electrode (RRDE) test indicated that Mo_0.3Fe₁Co₃–Se MAs has an excellent 2e⁻ ORR activity with H₂O₂ selectivity up to 88%, and the generated H₂O₂ is activated by the adjacent Fe site through heterogeneous Fenton process to generate ·OH.

The electrochemical reduction of CO₂ is an extremely potential technique to achieve the goal of carbon neutrality, but the development of electrocatalysts with high activity, excellent product selectivity, and long-term durability remains a great challenge. Herein, the role of metal-supports interaction (MSI) between different active sites (including single and bimetallic atom sites consisting of Cu and Ni atoms) and carbon-based supports (including C₂N, C₃N₄, N-coordination graphene, and graphdiyne) on catalytic activity, product selectivity, and thermodynamic stability towards CO₂ reduction reaction (CRR) is systematically investigated by first principles calculations. Our results show that MSI is mainly related to the charge transfer behavior from metal sites to supports, and different MSI leads to diverse magnetic moments and d-band centers. Subsequently, the adsorption and catalytic performance can be efficiently improved by tuning MSI. Notably, the bimetallic atom supported graphdiyne not only exhibits a better catalytic activity, higher product selectivity, and higher thermodynamic stability, but also effectively inhibits the hydrogen evolution reaction. This finding provides a new research idea and optimization strategy for the rational design of high-efficiency CRR catalysts.

Benzene (BEN) and cyclohexane (CYH), which have very close boiling points and a binary azeotrope, are the most difficult binary components in the separation of aromatic and non-aromatic hydrocarbons. This study further explored the separation mechanism and industrial application prospects of BEN ​+ ​CYH mixtures separated by a dicationic ionic liquid (DIL) [C₅(MIM)₂][NTf₂]₂ based on experimental research. The calculation results of the Conductor-like Screening model Segment Activity Coefficient (COSMO-SAC) model show that selectivity and solvent capacity of the DIL are significantly improved. The effects of different anions and cations on the microstructure distribution and diffusion behavior of BEN ​+ ​CYH system were investigated by quantum chemistry (QC) calculations and molecular dynamics (MD) simulations. The results indicate that the anion [NTf₂]⁻ has low polarity, uniform charge distribution, and a dual role of hydrogen bonding and π-π bonding, and the cation [C₅(MIM)₂]²⁺ has stronger interaction with BEN and higher selectivity than conventional cations. The liquid-liquid extraction and extractive distillation (LLE-ED) process using an optimized 65 mol/mol DIL ​+ ​35 mol/mol H₂O mixed solution as the extractant was proposed, which solved the problem of low product purity in the LLE process and high energy consumption in the ED process. Under the best operating conditions, the purity of CYH product was 99.9%, the purity of BEN product was 99.6%, the recovery rate of BEN reached 99.9%, and the recovery rate of DIL reached 99.9%. The heat-integrated LLE-ED process reduced total annual cost by 21.6%, and reduced CO₂ emissions by 48.0%, which has broad industrial application prospects.

Cooked rice and the vegetables like lettuce are common kitchen waste, which are carbonaceous materials and have the potential as feedstock for the production of activated carbon. Cooking is similar to hydrothermal treatment (HTC), which might impact the subsequent activation of kitchen waste. In this study, the HTC of lettuce, rice, or their mixture and the activation of the resulting hydrochars were conducted. The results indicated that cross-polymerization between the N-containing organics from lettuce and the sugar derivatives from rice took place in their co-HTC, which significantly increased the hydrochar yield. Activation of the hydrochar from the co-HTC generated the AC with a yield of 2 times that from direct activation of mixed lettuce/rice. However, the co-HTC facilitated aromatization, reducing reactivity with K₂C₂O₄ in activation and producing the AC with main micropores and low specific surface area. Activation of the hydrochar from HTC of rice followed the above trend, while that from lettuce was the opposite. The organics in lettuce were thermally unstable and could not undergo sufficient aromatization. The activation of hydrochar from HTC of lettuce thus generated the AC with the lowest yield, but the highest specific surface area (1684.9 m²/g), abundant mesopores, and superior capability for adsorption of tetracycline. However, the environmental impacts and energy consumption for the production of AC from the hydrochar of lettuce were higher than that from hydrochar of co-HTC.

While the industry has produced sugar-derived ethanol from the conventional method of fermentation for hundreds of years, other effective routes involving the direct transformation of carbohydrates still remain extremely rare. Very recently, an innovative chemo-catalytic method driven by the aqueous-phase catalysis was created for the synthesis of cellulosic ethanol, making a great breakthrough in the common ways as it can theoretically utilize all of the carbon atoms in sugars with faster kinetics; up to now, results from the relevant studies have been accumulated to a certain extent, but the periodic conclusions in this field are unfortunately absent. For this reason, this work tries to offer an overview of the cellulosic ethanol produced by chemo-catalytic routes, highlighting the present knowledge in relation to the technical efficiency, catalytic mechanisms as well as practical applications. At first, the advanced progress on the increasing efficiency from a varied type of catalytic systems are extensively discussed, which involves the specific functions of hybrid components from different strategies; meanwhile, the general influences of processing conditions, such as the hydrothermal severity and aqueous environments, are also identified. Subsequently, possible mechanisms behind the chemo-catalytic processes are widely elaborated by analyzing a number of experimental cases associated with the reaction network and its kinetic models. After that, the actual effects of this technique on the real biomass are collected to identify the positive/negative interactions between multiple components, together with the potential solutions on the semi-continuous processes of pilot scale application. The techno-economic analysis (TEA) is also calculated and compared with other similar methods, such as fermentation and gasification. Finally, several proposals aimed at upgrading the whole chain of chemo-catalytic processes are clearly provided, which may function as a guideline for future studies on the production of bio-ethanol from lignocellulosic materials.

Zinc and cadmium pollutants cause a significant environmental effect that cannot be ignored. Due to their considerable amount in an aqueous environment, industries are seeking suitable adsorbents that are environmentally friendly and inexpensive for removing metals from wastewater before disposing of them in surface waters. This research employed original MXene (MX) and chitosan-modified MXene (CSMX) to extract zinc (Zn(II)) and cadmium (Cd(II)) metal ions from water-based solutions. The composite material produced was analyzed using techniques such as X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET). The effects of contact duration, pH of the solution, and initial concentration of metal ions on the adsorption process of Zn(II) and Cd(II) onto both MX and CSMX composites were investigated. MX and prepared CSMX composite presented a high adsorption capacity for both studied heavy metals, which were 91.55 and 73.82 mg/g for Zn(II) and Cd(II) onto MX, 106.84 and 93.07 mg/g for Cd(II) and Zn(II) onto CSMX composite, respectively. Furthermore, the maximum competitive adsorption capacities for Zn(II) onto MX and CSMX composites are 77.29 and 93.47 mg/g, and for are Cd(II) 60.30 and 79.66 mg/g, respectively. Hence, the removal capacities for both single and competitive metal ions were superior to CSMX composite. However, the adsorption capacities after five successive regeneration sequences were only dropped by 13.2% for Zn(II) and 17.4% for Cd(II) onto the CSMX composite compared to the first cycle. These results confirm that both metals could be efficiently terminated from wastewater, which makes the prepared CSMX composite a favorable candidate adsorbent in practical applications.