Lithium-ion batteries (LIBs) are widely used as power storage systems in electronic devices and electric vehicles (EVs). Recycling of spent LIBs is of utmost importance from various perspectives including recovery of valuable metals (mostly Co and Li) and mitigation of environmental pollution. Recycling methods such as direct recycling, pyrometallurgy, hydrometallurgy, bio-hydrometallurgy (bioleaching) and electrometallurgy are generally used to resynthesise LIBs. These methods have their own benefits and drawbacks. This manuscript provides a critical review of recent advances in the recycling of spent LIBs, including the development of recycling processes, identification of the products obtained from recycling, and the effects of recycling methods on environmental burdens. Insights into chemical reactions, thermodynamics, kinetics, and the influence of operating parameters of each recycling technology are provided. The sustainability of recycling technologies (e.g., life cycle assessment and life cycle cost analysis) is critically evaluated. Finally, the existing challenges and future prospects are presented for further development of sustainable, highly efficient, and environmentally benign recycling of spent LIBs to contribute to the circular economy. A critical review of the recent developments in the recycling of spent Li-ion batteries using five major technologies (direct recycling, pyrometallurgy, hydrometallurgy, bioleaching and electrometallurgy) and evaluation of their sustainability.

Most of the developed flexible hydrogel supercapacitors struggle to maintain their electrochemical stability and structural integrity under tensile strain. Therefore, developing a flexible supercapacitor with excellent mechanical properties and stable electrochemical performance under different strains remains a challenge. Based on the previous cartilage-like structure, we designed a new coarse nanofiber bundle and ordered network. A coarse nanofiber bundle and ordered network skeleton was constructed by directional freezing and filled with polyvinyl alcohol (PVA) to serve as a soft matrix to prepare PVA-SNF-CNTs-PPy-3 hydrogel electrode, which has high tensile strength (6.22 MPa) and fatigue threshold (8759.8 J/m2). In addition, the loading of carbon nanotubes and polypyrrole onto the SNF-ordered network enabled the conductive material to form an ordered conductive energy storage network along the skeleton, providing an area-specific capacitance of up to 23.96 F/cm2. The coarse nanofiber bundle and ordered network provided supercapacitors with the least capacitance consumption under 150 % deformation, and the capacitance retention was >98.2 %. After repeated stretching (3000 times), the capacitance remained >91.45 %. This study provides new ideas for the development of flexible supercapacitors with high capacitance and high mechanical reliability.

As a complementary or alternative approach to experiments, theoretical computation of adsorption between carbon materials and emerging aromatic organic contaminants (AOCs) is increasingly important in elucidating adsorption mechanisms and characteristics, as well as their predictions. In this study, the adsorption energies between graphene and 112 AOCs were first analyzed by density functional theory (DFT-D). By the use of quantum molecular descriptors, different machine learning (ML) algorithms were developed. EXtreme gradient boosting exhibited the best performance among the four ML algorithms investigated, showing the lowest root-mean-square percentage error of 4.5% for the test data set. Accordingly, the interpretable ML technique (i.e., SHAP) assessed the importance and dependence of descriptors in the adsorption mechanisms of AOCs to graphene. The global interpretation confirmed that the molecular-volume-induced van der Waals interactions including pi-pi stacking are dominant, whereas the other interactions (e.g., induced hydrogen and electrostatic interactions) are comparably less significant in the adsorption of most AOCs on graphene. In contrast, using local interpretation, hydrogen bonds and induced dipole interactions with surrounding water were identified as important explanatory variables in the adsorption of AOCs containing carbonyl and sulfur functional groups. Therefore, the developed DFT-D-based ML models could be a reference model for theoretical and experimental studies.

Hydrothermal process is an emerging technology that contributes to sustainable production of biomass-derived chemicals, fuels, and materials. This technology uses hot compressed water to convert various biomass feedstocks including recalcitrant organic compounds in biowastes into desired solid, liquid, and gaseous products. In recent years, considerable progress has been made in the hydrothermal conversion of lignocellulosic as well as nonlignocellulosic biomass to value-added products and bioenergy to fulfill the principles of circular economy. However, it is important to assess hydrothermal processes in terms of their capabilities and limitations from different sustainability aspects so that further advances can be made toward improvement of their technical maturity and commercialization potential. The key aims of this comprehensive review are to (a) explain the inherent properties of biomass feedstocks and physio-chemical characteristics of their bioproducts, (b) elucidate related transformation pathways, (c) clarify the role of hydrothermal process for biomass conversion, (d) evaluate the capability of hydrothermal treatment coupled with other technologies for producing novel chemicals, fuels and materials, (e) explore different sustainability assessments of hydrothermal processes for potential large-scale applications, and (f) offer our perspectives to facilitate the transition from a primarily petro-based to an alternative biobased society in the context of changing climate.

Soil moisture, as the main characteristic parameter of the surface, plays an important role in climate change, energy exchange, and crop yield estimation. In order to remove the influence of vegetation coverage and roughness on soil moisture retrieval, a cooperative inversion method based on Water Cloud model and Oh model is proposed to retrieve soil moisture in winter wheat covered farmland areas using Sentinel-1/2 multi-source remote sensing data. The influence of winter wheat coverage on radar backscattering coefficient is removed by using the improved Water Cloud model with vegetation coverage and vegetation index fusion extracted from Sentinel-2 data. The attenuation factor in the Water Cloud model is solved by using the optimization theory. The soil moisture in the study area is retrieved based on the backscattering coefficient of VV and VH polarization Sentinel-1 data through the Look Up Table established by Oh model. The experimental results show that, based on the proposed method, compared with VH polarization, the soil moisture inversion from VV polarization data has a better effect, with a determination coefficient of 0.6577, a Root Mean Square Error of 0.0391 cm3 /cm3 , and a Mean Absolute Error of 0.0303 cm3 /cm3 , demonstrating the application potential of the proposed method in soil moisture retrieval.

The conversion of biowastes to carbonaceous materials (CNMs) has received increasing attention in the context of environmental sustainability. Herein, we report the synthesis of magnetic CNMs from the waste biomass, palm kernel shell (PKS), together with iron salts using a combination of hydrothermal and pyrolysis processes for the first time. Specifically, the addition of FeSO4 center dot 7H(2)O and FeCl3 center dot 6H(2)O to PKS tends to produce iron carbide and iron oxides, which contribute to the catalytic conversion of biowastes to various CNMs. The outcome of adsorption experiments reveals that the simultaneous adsorption of p-nitrophenol (PNP) and Cu(II) onto magnetic CNMs is mainly controlled by the availability of surface adsorption sites and the occurrence of intra-particle diffusion. The synergistic adsorption of PNP and Cu(II) is found when the initial concentration of PNP is less than 20 mg/L. With the concentration of PNP exceeding 20 mg/L, the adsorption of Cu(II) is suppressed due to preferential adsorption of PNP onto magnetic CNMs. The spent magnetic CNMs can be easily recovered, regenerated and reused in their adsorption capacity. Our study outcomes provide a novel strategy to synthesize biowaste-derived magnetic CNMs for practical environmental remediation applications.

Understanding the reaction mechanism of OH•-mediated oxidation of organic micropollutants (OMPs) contributes to the assessment and development of advanced oxidation processes (AOPs) for removal of OMPs in water environment. In this study, a theoretical approach using quantum chemical calculation (QCC) was employed to investigate the prediction accuracy of the reaction mechanism (i.e., reaction site and rate) for OH•-mediated oxidation of phenol, where the hydroquinone and catechol are generated as transformation products (TPs) via radical and electrophilic reactions. We compared three different levels of theory (Hartree-Fock, B3LYP, and M06-2X) with 6-311 + G (2d,2p)/SMD, and the reaction site and rate constants were predicted by the Fukui function and transition state theory, respectively. Overall, the prediction accuracy of the TPs formation mechanism was the highest in the calculations using M06-2X. For example, the initial OH• addition to phenol was predicted to occur with a probability of 77% for the ortho position and 23% for the para position, which was consistent with the experimental observation. By applying the transition state theory, the rate constants toward TPs formation pathway can be reasonably reproduced, suggesting that M06-2X has an effective function for polycyclic reactions. However, the observed discrepancies in rate constants are inferred from dispersion effects and the multi-reference property in the computational system or derived from mismatch of target reactions between theoretical calculations and experiments. Overall, this study provides an insight into QCC application for investigating the formation mechanism of TPs in AOPs for removal of OMPs in water environment.

Thermal transformation of biowaste to carbon foam provides an economically attractive and eco-friendly strategy for biowaste recycling. Herein, we report a novel self-foaming approach involving modified hydrothermal carbonization (HTC) and pyrolysis to produce carbon foam from biowaste. Notably, biowaste-derived carbon foam consists of foam structure and multi-porous structure, originated from the self-forming process of aromatic segments during modified HTC and pyrolysis processes. Based on characterization results, biowaste-derived carbon foam possesses hierarchical micropore, mesopore and macropore with increasing sp(2) hybridized carbon atoms. We demonstrate the potential applications of this material for CO2 capture. Biowaste-derived carbon foam exhibits 5.0-fold and 4.8-fold CO2 uptake at 35 C-o and 50 C-o, respectively, compared to those of pristine biowaste. The recycling of biowaste to carbon foam for CO2 capture contributes to decarbonization efforts worldwide by a synergistic way, including the photosynthesis of atmospheric CO2 to biomass, carbon sequestration in carbon foam and CO2 capture by carbon foam.

Electrochemical advanced oxidation processes (EAOPs) have been extensively investigated for the degradation of emerging contaminants. However, only the composition of electrodes is well studied but less for the electrode configuration. This work developed a new configuration of electrodes rolled along the optimized Archimedes spirals shaping a “Swiss roll”. The effects of electrode distance, electrode area and current were investigated via regulating the electrode configuration and EAOPs conditions. The increasing electrode distance contributed to the H2O2 accumulation but went against the anodic oxidation of carbofuran. The EAOPs with moderate electrode distance showed synergetic removal of carbofuran by electro-Fenton and anodic oxidation processes. The current density was optimized by changing electrode area and current. The increasing current density promoted the generation of H2O2 and •OH, which could significantly improve the removal of carbofuran by electro-Fenton process. Accordingly, novel kinetic models were developed and validated with experimental data to describe the coupled electro-Fenton and anodic oxidation reactions. Examination of transformation products indicated that the continuous production of •OH accelerated the cleavage and ring-opening of carbofuran and transformation products. The reactor consumed low electrical energy (34.4 kWh/kg) in long-term EAOPs, providing promising solutions in terms of performance and cost in large-scale applications.

Synthesis and formation mechanisms of biomass-derived carbonaceous materials are critically reviewed in terms of biomass sources, conversion methods and additives for energy and environmental applications.

The solid-liquid equilibrium behavior of (2,4-dichlorophenoxy)acetic acid (2,4-D) was investigated. The solubility of 2,4-D in fifteen pure solvents were measured using the gravimetric method from 278.15 K to 323.15 K. The Hirshfeld surface analysis provided quantitative information about intermolecular inter-actions in 2,4-D crystal structure. The MEPs analysis showed that the carboxyl group of 2,4-D molecule was the main site for hydrogen bond formation. Besides, four thermodynamic models including the mod-ified Apelblat equation, van't Hoff equation, kh equation, and NRTL model were used to correlate the sol-ubility data, and the results showed that the modified Apelblat equation has the best fitting. The calculation results of thermodynamic properties such as mixing enthalpy, mixing entropy and mixing Gibbs free energy showed that the dissolution process of 2,4-D was spontaneous. KAT-LSER model was used to investigate the solvent effect. The results revealed that solvent-solvent interaction had a signif-icant unfavorable effect to the solubility of 2,4-D. Finally, solvation free energy analysis was performed to quantitatively explain the differences in solubility of 2,4-D in different solvents. (c) 2021 Elsevier Ltd.

Screening of suitable coformers is a major challenge during the development of cocrystals. To guide and simplify the cocrystal synthesis process, we evaluated three different predictive methods as well as their combinations during the cocrystallization of 2-amino-4,6-dimethoxypyrimidine (MOP) with 63 components. The conductor-like screening model for the real solvents (COSMO-RS) approach offered the best predictive results among three methods with an overall success rate of 84.1%. When combined with molecular complementarity (MC) analysis, the success rate was up to 85.7%. The Hansen solubility parameters (HSP) method did not deliver a satisfying outcome no matter if used individually or in combination for the MOP system. In addition, based on the screened results, 21 new solid phases of MOP were experimentally observed. Among them, the crystal structures of 10 multicomponent crystals (cocrystals and salts) were revealed by single crystal X-ray diffraction analysis (SCXRD), and their thermodynamic and spectroscopy properties were also characterized. The Hirshfeld surface analysis and the molecular electrostatic potential (MEP) surface analysis were conducted to explore the interactions in multicomponent crystals and the origin for salts and cocrystals. The cases in this study not only enriched the solid forms of MOP, evidenced the feasibility of the combined screening method, but also set an effective example for choosing potential coformers to prepare multicomponent crystals.

For the purpose of enhancing the solubility and humidity stability of pymetrozine (PMZ), a highly active but nonbiocidal pesticide, new multicomponent crystals were developed based on the connotation of crystal engineering. In the coformer screening process, a combined method, the Conductor-like Screening Model for Realistic Solvents (COSMO-RS) approach together with Cambridge Structural Database (CSD) analysis, was employed to shorten the screening process. Further, seven single crystals of PMZ's new multicomponent solids were obtained including three cocrystals and four salts. Single-crystal X-ray diffraction together with Hirshfeld surface analysis clarified the detailed structure and the molecular interactions in these new crystals. Thermodynamic properties and spectral data were characterized by thermogravi-metric analysis, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. Hygroscopicity and solubility of the seven cocrystals/salts were investigated by dynamic vapor sorption and equilibrium solubility measurement, respectively. Multicomponent crystals not only exhibit better stability against humidity and but also higher water solubility than PMZ. Meanwhile, the insecticidal activity of PMZ was preserved during the formation of cocrystals/salts. On this basis, we conducted the atoms-in-molecules (AIM) analysis and the molecular electrostatic potential surfaces (MEPs) analysis to assess the strength of hydrogen bonds and reveal the origins of salt/cocrystal formation. So, the variations and origins of these physicochemical properties were rationalized and explained on the atomic scale. On the whole, the efficiency of the novel combined coformers screening method was verified and new multicomponent crystalline forms of PMZ were successfully obtained to prevent the parent compound from hydrating transformation.

Two theoretical methods, self-consistent Nyvlt-like approach and Sangwal's classical 3D nucleation theory-based method, are employed to analyze the effects of additives (sodium sulfate) on the nucleation behavior of taurine. By correlating the measured metastable zone width of taurine containing different sodium sulfate concentrations, with saturation temperature and cooling rate, nucleation kinetic parameters in both two methods are determined. Fitting results demonstrate that higher sodium sulfate concentration results in the increase of solid-liquid interfacial energy gamma, contrarily higher saturation temperature has the opposite effect thus changing of nucleation rate. The molecular modeling techniques are then applied to investigate the changes in the morphology of taurine which caused by the presence of sodium sulfate. Through molecular dynamic simulations, the interaction energy of sodium sulfate with taurine crystal faces are obviously larger than those of taurine and these differences on the (011) and (11-1) are more significant than those on (021) and (111) faces. As a result, the growth of (011) and (11-1) faces is inhibited and the morphology of taurine crystal is modified from needle to columnar. The influence of sodium sulfate on taurine studied in this work provides theoretical guidance for industrial production.

Graphene-based materials with a conjugated π region possess unique advantages for treating wastewater contaminated with phenolic compounds. To investigate the interaction mechanisms and optimize the removal efficiency of phenol and p-nitrophenol, nitrogen-doped reduced graphene oxide (N-RGO) with an enlarged conjugated π region and increased hydrophobicity was prepared by annealing a composite of chitosan exfoliated and anchored in a graphene oxide matrix. Results showed that the equilibrium adsorption capacity of N-RGO for phenol and p-nitrophenol was 155.82 and 80.60 mg/g, respectively, at an initial concentration of 200 mg/L, pH of 6, and contact temperature of 30 °C. The optimized removal efficiency was attributed to robust π-π and hydrophobic interactions. Furthermore, regeneration experiments showed that N-RGO could retain a high removal efficiency (> 80 %) over five cycles of reuse. These findings suggest that N-RGO is a promising technique for the removal of phenolic compounds from wastewater using an efficient and recyclable adsorbent.

Green petroleum coke, a form of industrial waste produced in the oil-refining process, was used to synthesize nitrogen-doped graphene-like plates (N-GLPs) together with melamine. In this study, characterization and batch experiments were performed to elucidate the interaction mechanism of N-GLPs and bisphenol A (BPA). Structural analysis of N-GLPs, including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS), showed an obvious graphene-like structure and successful nitrogen doping. In addition, compared with 8.0 m2/g for green petroleum coke, the BET surface area of N-GLPs markedly increased to 96.6 m2/g. The influences of various factors, including contact time, temperature, and initial pH on BPA removal efficiency were investigated. It was found that 92.0% of BPA was successfully removed by N-GLPs at 50 °C. Based on the adsorption experiments, it was shown that electrostatic attraction, hydrogen bonding, and π-π interaction enhanced the adsorption capacity of N-GLPs for BPA. According to the thermodynamic data, the adsorption process was spontaneous, physical, and endothermic in nature. Therefore, N-GLPs are efficient adsorbent material to remove BPA from wastewater.

The solubility data of sorbic acid in binary systems of (ethanol + water), (1-propanol + water) and (2-propanol + water) were measured from 283.15 to 323.15 K using the static equilibrium method under atmospheric pressure. It was found that the solubility of sorbic acid in the three binary solvent systems increased with increasing temperature as well as increasing initial mole fraction of organic solvent in these systems. The van’t Hoff–Jouyban–Acree model, the modified Apelblat–Jouyban–Acree model and the CNIBS/R-K model were proposed for correlating the experimental solubility values in various solution systems. Furthermore, the dissolution thermodynamic properties of Gibbs energy change (Δ sol G o ), molar enthalpy change (Δ sol H o ) and molar entropy change (Δ sol S o ) were calculated from the experimental solubility data, using the van’t Hoff equation. The positive values of Δ sol G o , Δ sol H o and Δ sol S o indicate that these dissolution processes of sorbic acid in the solvents studied were all endothermic and entropically favorable. In addition, the change of dissolution enthalpy was the main contributor to the positive value of the molar Gibbs energy of the dissolution process. The experimental solubility and the models used in this work would be conducive to purifying sorbic acid from its crude mixtures.

Nicosulfuron (NS) is a widely used sulfonylurea herbicide because of its high selectivity, broad spectrum of herbicide activity, and excellent performance. In this work, nicosulfuron methanol solvate (NS-MeOH) and [[3-[(Dimethylamino)carbonyl]-2-pyridinyl]sulfonyl]carbamic acid methyl ester (PCM) as a product of methanolysis of NS were obtained. Both of their structures were determined by a single crystal X-ray diffraction. A broad range of analytical techniques was applied to characterize the NS-MeOH, such as Powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and hot stage microscopy (HSM). Combined with the analysis of the Independent gradient model (IGM), Atom-in-molecules (AIM), and Hirshfeld surface (HS), direct insights into the role of solvent played in the formation of NS-MeOH and the mechanism of solid-to-solid phase transformation of NS-MeOH could be obtained. In addition, the aqueous solubility of NS was improved through the formation of NS-MeOH. A systematic investigation of herbicidal activity of NS and PCM was carried out. It was found that NS and NS-MeOH had similar herbicidal activities at the experimental concentrations while PCM exhibited significantly lower activity. It was suggested that methanolysis of the sulfonylurea bridge in the NS molecule exerted a great influence on the herbicidal activity.

Simultaneously improving the hydroxide conduction capacity and anti-swelling property of anion exchange membranes (AEM) is a big challenge in the field of fuel cells. In this work, the poly (vinyl imidazole) functionalized carbon nanotube (PVI@CNT) was synthesized as a dual functional nanofiller and introduced into the imidazole poly(ether ether ketone) (IPEEK) matrix. The imidazolium groups on the PVI@CNT offer additional ion conducting sites to improve the hydroxide conductivity. The imidazolium groups also react with the IPEEK to form a crosslinking structure along the nanotubes, thus ensuring favorable anti-swelling property. The nanohybrid membrane with 15 wt % PVI@CNT (IPEEK/PVI@CNT-15) shows a maximum conductivity of 121 mS cm(-1) at 70 degrees C, 100% relative humidity (RH). Meanwhile, the crosslinking structure suppresses the swelling degree from 42.0% (pristine IPEEK) to 17.8% (IPEEK/PVI@CNT-15). The single H-2/O-2 fuel cell performance of the membrane electrode assembly (MEA) with IPEEK/PVI@CNT-15 membrane reveals a high power density of 128.7 mW cm(-2). Moreover, the incorporation of the PVI@CNT also enhances the alkali stability and the thermal stability of the nanohybrid membranes. (C) 2019 Elsevier Ltd. All rights reserved.

An effective strategy to improve both the conductivity and alkaline stability of anion exchange membranes (AEMs) was proposed by incorporating imidazolium ionic liquids (ImILs) modified 1D carbon nanotubes (IL@CNT) into imidazolium-based poly (ether ether ketone) (ImPEEK). Two types of ionic liquids (IL-M and IL-B) with different alkaline stability were chemically attached to CNTs. The introduction of IL@CNT provided the hybrid membranes with additional ion hopping positions and 1D long-range ion-conducting channels. The ImPEEK/IL-B@CNT-6 membrane with a high ion exchange capacity (IEC) of 2.49 mmol g(-1) possessed the hydroxide conductivity of 134.52 mS cm(-1) (70 degrees C, 100% RH) which was 1.7 times that of the pure ImPEEK membrane (80.20 mS cm(-1)). Meanwhile, the hybrid membranes showed enhanced alkaline stability due to the steric hindrance offered by CNTs and good alkaline resistance of IL-B with more bulky substituents. The residual ratio of hydroxide conductivity of ImPEEK/IL-B@CNT-8 after being treated in 2 M KOH at 50 degrees C for 48 h reached 77.47% (54.37% for pure ImPEEK and 70.21% for ImPEEK/ILM@CNT-8). The theoretical calculations of LUMO energy for IL-M (-1.83 eV) and IL-B (-1.74 eV) were in good accordance with experimental results. The ImPEEK/IL-B@CNT-6 hybrid membrane presented an improved fuel cell performance with the peak power density of 80.59 mW cm(-2) at 50 degrees C which was 1.6 times that of the pure ImPEEK membrane. Mechanical properties, dimensional and thermal stability of the as-prepared hybrid membranes were also enhanced due to the improved interface compatibility.