Consumption Of Chemical Reagents Research Articles

Determining rational parameters for the treatment of concentrated wastewater from etching site by using combined systems producing sediments of predefined composition

The object of this study is model solutions, spent sulfuric acid and chloride acid etching solutions, degreasing of metal products at enterprises. The paper reports results of research on the possibility of obtaining sediments of predefined composition and reducing the consumption of chemical reagents in comparison with conventional cleaning schemes. The systematization of the elements of the technological scheme has been shown, which provides for the treatment of concentrated wastewater of the etching area in combined systems with obtaining sediments of predefined composition and is the basis for the implementation of resource-saving technology. Rational parameters were established for the state (рН=3‒4, Eh=+0.3‒+0.33 V, and rH2=16.3–19.38 V) and technological parameters (degree of iron extraction ψ=0.8, reagent consumption from the stoichiometric norm of B=0.8). Such parameters provide the proper conditions for the oxidation of organic compounds and their co-precipitation with insoluble iron hydroxy compounds (the maximum degree of extraction of organic impurities is 86 %). The formed precipitate corresponds to the FeOOH.nH2O composition, contains 2‒3 % of organic impurities, and is subject to burial. As a result of studies on the treatment of concentrated iron-containing wastewater, the obtained sediment is ready for further utilization by processing. The composition of this sediment corresponds to the natural mineral limonite FeOOH (Fe2O3.nH2O) and is formed at pH values from 3.5 to 7.5 with rH2 values from 26 V to 21 V and at technological regeneration parameters of pH=4.0–4.6; rH2 =23.34–32.25 V. As a result of research into the deep purification of wastewater using a magnetic device, a suspension of sediment of ferromagnetic impurities (hydroxo compounds of iron) is obtained, which could be the basis for extraction or production of magnetically favorable dispersed material.

Evaluation of the effect of desliming and alternatives in iron ore reverse flotation circuits

Iron ore reverse flotation has been the main concentration process applied in iron ore processing plants since the 1970s. The performance of this process has been strongly affected by the control of the previous desliming stages. The presence of ultrafine particles promotes selectivity losses in the flotation circuits, in addition to a significant increase in the consumption of chemical reagents and pumping energy. The removal of ultrafine particles promotes metal losses, the need for additional dewatering steps, difficulties in handling and stacking together with flotation waste. This study focuses on investigating the feasibility of replacing desliming with high intensity vertical magnetic concentrators (VPHGMS). Pilot tests were carried out with this type of magnetic concentrator followed by flotation, the results show an increase in metal recovery of 4% when compared to the traditional desliming and flotation circuit, drastic possibility of reducing energy, chemical reagents and foot print and potential to reduce capex and opex by 22% and 24%, respectively, for new projects.

Realizing Lean-Leachate Recycling of Spent Lithium Nickel Oxides by Dynamically Stabilizing the Hole-Mediated Diffusion Kinetics.

While hydrometallurgy is the primary technology for recycling spent lithium-ion batteries due to various advantages, it still involves substantial consumption of chemical reagents and poses challenges in wastewater emission. Herein, we report the realization of cathode recycling under lean-leachate conditions by dynamically stabilizing hole-mediated diffusion kinetics, which is enabled by synchronizing the extraction step during the leaching stage, thus continuously removing the dissolved ions out of the leachate. Theoretical molecular dynamics simulations predict that preventing the accumulation of the dissolved ions is efficient for keeping the leaching process proceeding. Experimentally, even with a small dosage of leachate (0.5 mL), a 94.51% leaching efficiency can be achieved (90 °C, 40 min) for spent LNO materials. Considering that our strategy is not limited to a specific materials system, it could be extended to recycle other valuable materials (including LCO or NCM 811) with minimal leachate usage.

Renewable ammonium chloride-induced calcium leaching of gold and copper tailings and selective preparation of vaterite CaCO3 by CO2 mineralization

This study introduced a high-value green processing solution for copper tailings to prepare high-purity vaterite from gold-copper tailings. The active reaction components were determined through Gibbs free energy calculations. The study discusses the impact of different experimental parameters on the leaching rate of Ca2+ and the degree of mineralization in gold-copper tailings, and then considers the influence of different dispersants on improving the stability of vaterite. The results show that the optimal leaching efficiency of Ca2+ in the NH4Cl solution is 75%, and the optimal mineralization efficiency is 87%. Under appropriate mineralization conditions, vaterite CaCO3 with d50 < 12 μm, a purity of 98%, and a whiteness of 98.7% can be prepared. The precipitated vaterite is affected by the pH swing method connected with the neutralization reaction. The presence of excess NH3 and supersaturated CO2 are necessary for the formation of vaterite-type CaCO3. Morphological analysis results show that dispersants such as polyacrylamide and sodium tripolyphosphate can improve the dispersibility of vaterite, preventing agglomeration and enabling its stable existence in aqueous solutions. Nanoparticle aggregation and crystal growth are two possible mechanisms for the formation of vaterite. The leaching-mineralization cycle technology using NH4Cl as the leaching solution meets the requirements for CO2 removal and alkaline industrial waste residue treatment, while avoiding the significant consumption of chemical reagents in traditional mineralization. This method provides a pathway for producing vaterite using copper tailings and has a broad market prospect.

Ingenious use of autocatalytic hydrodeoxygenation for the separation and recovery of oil and iron from rolling oil sludge

This paper introduces a transformative hydrodeoxygenation process for the simultaneous recovery of oil and iron from hazardous rolling oil sludge (ROS). Leveraging the inherent catalytic capabilities of iron/iron oxide nanoparticles in the sludge, our process enables the conversion of fatty acids and esters into hydrocarbons under conditions of 4.5 MPa, 330 °C, and 500 rpm. This reaction triggers nanoparticle aggregation and subsequent separation from the oil phase, allowing for effective resource recovery. In contrast to conventional techniques, this method achieves a high recovery rate of 98.3% while dramatically reducing chemical reagent consumption. The reclaimed petroleum and iron—ready for high-value applications—are worth 3910 RMB/ton. Moreover, the process facilitates the retrieval of nanoscale magnetic Fe and Fe0 particles, and the oil, with an impressive hydrocarbon content of 87.8%, can be further refined. This energy-efficient approach offers a greener, more sustainable pathway for ROS valorization.

Intensification of dying of silk and cotton-silk fabrics with water-soluble dyes in the presence of chitosan

The results of the study of the effects of textile excipients are striking for the intensification of the processes of dyeing silk and mixed fabrics with active dyes. For the first time, a technique has been developed for using chitosan isolated from dead bees Apis Mellifera as an intensifier. It was found that treatment with chitosan leads to an increase in their sorption capacity and the appearance of centers of charge in silk and cellulose fibers. A certain nature of the bond and the chemical mechanism of action in the fiber-chitosan-dye system, as well as the effect of intensifiers on the degree and amount of fixation of active dyes on the fiber. The article uses modern physical and chemical research methods: IR and UV spectroscopy, scanning electron microscopy (SEM), standard methods for determining the physical and mechanical properties, as well as color indicators of the quality of dyed fabrics. The practical significance of the results of the study is explained by the fact that the dyeing of silk and cotton-silk fabrics in the presence of chitosan improves the color characteristics of the fabric, reduces the use of imported dyes and reduces the consumption of chemical reagents.

A tubular flexible gas sensor fabricated by liquid-borne ultrasound for higher sensitivity and stability

Further enhancement of sensitivity and stability of flexible gas sensors with a low cost will definitely widen their application range. In this work, a novel structure for flexible gas sensors is proposed and developed to significantly enhance the sensing performance, in which a sensing layer is coated on the inner wall of a flexible tube. To coat the sensing layer onto the inner wall, liquid-borne ultrasound is utilized, which not only makes the inner wall coating feasible at room temperature and normal pressure, but also has many green features such as low chemical reagent consumption. To the best of our knowledge, this is the first attempt to apply liquid-borne ultrasound in the coating process for flexible gas sensors. Tubular SnO2-rGO NH3 sensors fabricated by this method, have a measured LDL of 1 ppm, which is lower than the lowest one (5 ppm) of reported planar NH3 sensors with the same sensing material. The sensing response only decreases about 3.6 % for 1 ppm NH3 after 2000 loading-unloading cycles at 40 % strain and 0.5 Hz frequency. Apart from these merits, the inner wall sensing structure can protect the sensing layer from contaminants and touching. Thus, the flexible gas sensors developed in this work have very good mechanical stability.

Development of a resource-saving technology for the treatment of ferrum-containing wastewater from etching operations

The object of this study is wastewater from chloride and sulfate etching operations. This paper reports results of research on ways to reduce the consumption of chemical reagents in wastewater treatment systems from etching operations. Spent etching solutions are subject to regeneration with return to the production process and partial dosing to the main stream of wastewater. It was found that at a ferrum concentration of 30 g/l in etching solutions, the solution must be treated with an alkaline reagent (10–20 % NaOH) to pH=3.5–4.0 in order to return to the technological process. In this case, the final concentration of ferrum is 11 g/l. The use of hydrogen peroxide (20–40 % H2O2) together with the alkaline reagent makes it possible to increase the degree of extraction by 30 %, that is, the final concentration of ferrum is 8 g/l. When discharging 1 m3 of etching solutions, 0.5 m3 is subject to regeneration and, after mixing with 0.5 m3 of the commercial reagent (HCl) it returns to the technological process. Commercial acid consumption is reduced by 50 %. It was shown that the use of individual flows of waste solutions as a chemical reagent reduces the cost of reagents for their neutralization (saving alkaline reagent is 80 %). Thus, 1.2 kg/m3 of a commercially available reagent (NaOH) is consumed per 1 m3 of solutions (etching and degreasing) after mixing them, and, without mutual neutralization, this consumption is 6 kg/m3. To neutralize etching solutions, it is recommended to carry out the process in the range of pH=6.5–7.5. For a solution in which Fe3+ ions predominate with an initial concentration of 0.53 mol/L, a degree of extraction of 0.9 is achieved, and the total consumption of the reagent (7.1 mol/l) exceeds the stoichiometric one by only 10 %. Deep purification from ferrum-containing impurities using a magnetic device expands the possibilities of practical implementation of further desalting with inverse osmosis.

WATER PREPARATION IN HOTEL AND RESTAURANT SYSTEMS

In these studies, methods of water treatment in hotel and restaurant systems are considered. Having studied the process of filtering water on polystyrene foam loading, the possibility of reducing the consumption of chemical reagents during subsequent liming has been established. Presented technologies of desalination and deep softening of water achieve a reduction in the consumption of reagents for the process, the elimination of secondary pollution by Cl-, Na⁺ ions. The possibility of controlling the liming process (stages of primary sediment formation from a homogeneous system) based on pH and Eh parameters has been demonstrated. The subsequent H+ cationization of a part of the flow with its subsequent mixing with the main flow after liming allows obtaining water for household purposes and the subsequent Na+ cationization of deep softening of boiler water with lower consumption of reagents for ionite regeneration. Strongly acidic cationite NRV 100R in the form of H+ and strongly acidic cationite C 100E in the form of Na+ were used as the studied ion exchange resins. The technology may include an additional filtering operation through a special loading in order to prepare water for health and cosmetic purposes. As a result of research, it was established that pre-filtering of water on polystyrene foam loading (filter) allows to reduce the consumption of reagent in the liming process, due to the reduction of the content of hydrogen phosphates, hydrogen carbonates, sulfates and hydrosulfates, for the extraction of which a significant amount of reagent was spent. A package of documentation for the production of a block-module complex for water softening and desalination has been developed. In the proposed installation, a sorption block with a special (therapeutic) load, approved by the Ministry of Health of Ukraine for the food industry and for water treatment of unlimited use (for health and cosmetic purposes) can be provided. Keywords: water treatment, water softening, hotel and restaurant business, styrofoam loading, filtering, liming.

ECOLOGICAL FEATURES OF SOAKING AND ASH PROCESSES IN THE PRODUCTION OF LEATHER

Ecological and colloid-chemical features of soaking-ash processes in processing of raw cattle leather materials at production of elastic leather for uppers of footwear according to operating and developed resource-saving technologies are investigated. To evaluate the effectiveness of the technological processes used a set of physic-chemical and operational properties of leather semi-finished products at different stages of its formation to the finished material. Resource-saving ecologically oriented technology of soaking and ash processes in leather production for shoe uppers from raw salted conserved materials – bull skins has been developed. Physicochemical, technological and ecological features of existing and developed technologies are studied. The developed technology due to the increase of process temperature provides more efficient use of chemical reagents, reduction of concentrations of environmentally hazardous reagents, process duration and energy consumption per unit of output. At the same time, the total consumption of chemical reagents is reduced by 2.2 times, and in the waste technological solutions the concentration of sodium sulfide and calcium hydroxide – by 2.9 and 4.4 times, respectively. However, the developed resource-saving environmentally friendly technology is characterized by a reduction in biological and chemical oxygen demand for the destruction of organic and inorganic substances in the waste soaking-ash solution after treatment of 1 ton of raw materials by 30.0 and 21.0%, respectively. By reducing the duration of the technological process by 2.3 times, the new technology can be considered as energy efficient. The developed resource-saving technology provides the formation of leather material for shoe uppers with an increased yield of 3.9%, and its performance properties meet the requirements of DSTU 3115-95. The results obtained in the development of environmentally friendly resource-saving technology of soaking ash processes for footwear leather uppers from raw cattle leather materials can be effectively used in the development of new innovative technologies for the manufacture of leather materials from a wide range of other raw materials.

Resource Utilization of Acid Mine Drainage (AMD): A Review

Acid mine drainage (AMD) is a typical type of pollution originating from complex oxidation interactions that occur under ambient conditions in abandoned and active mines. AMD has high acidity and contains a high concentration of heavy metals and metalloids, posing a serious threat to ecological systems and human health. Over the years, great progress has been made in the prevention and treatment of AMD. Remediation approaches like chemical neutralization precipitation, ion exchange, membrane separation processes, and bioremediation have been extensively reported. Nevertheless, some limitations, such as low efficacy, excessive consumption of chemical reagents, and secondary contamination restrict the application of these technologies. The aim of this review was to provide updated information on the sustainable treatments that have been engaged in the published literature on the resource utilization of AMD. The recovery and reuse of valuable resources (e.g., clean water, sulfuric acid, and metal ions) from AMD can offset the cost of AMD remediation. Iron oxide particles recovered from AMD can be applied as adsorbents for the removal of pollutants from wastewater and for the fabrication of effective catalysts for heterogeneous Fenton reactions. The application of AMD in beneficiation fields, such as activating pyrite and chalcopyrite flotation, regulating pulp pH, and leaching copper-bearing waste rock, provides easy access to the innovative utilization of AMD. A review such as this will help researchers understand the progress in research, and identify the strengths and weaknesses of each treatment technology, which can help shape the direction of future research in this area.

New geophysical logging techniques for practical problem solving at complex hydrogenetic uranium deposits

In-situ uranium recovery features high economic efficiency and low environmental impact as compared with other uranium production techniques. The article presents the experimental results on the application of new geophysical logging methods at a uranium deposit of hydrogenetic type. Complex hydrogenetic uranium deposits have a nonuniform lithology, varied permeability and alternation of permeable and water-resistant rocks. The development of such deposits is often complicated by a number of factors affecting the production process. The common methods of geophysical research in wells provide insufficiently reliable information about the geological structure of interwell space. As a result, it is difficult to control and monitor the production process, which can lead to inefficient consumption of chemical reagents, undesirable leakage beyond the limits of production blocks, incomplete extraction of uranium reserves, etc. To solve the problem of insufficient studies of interwell space, the method of radiowave geointroscopy was tested. This method is based on the measurement of electrical resistance. The tests were carried out in two stages, during the periods of high-rate production. By comparing the measurement results in different dimensions, the electrical resistance maps were plotted. The interpretation of the measurement results made it possible to obtain reliable data on the actual distribution of solutions in the interwell space in a given period of time, to identify areas of excessive concentrations of solutions (stagnant zones), to assess acidification dynamics in production blocks, and to delineate potentially difficult areas of the blocks.

Mechanical Flotation of Mineral Particles with an Underwater Speaker

ABSTRACT This paper aims to demonstrate a safe, non-chemical approach for improving the efficiency of froth flotation. Laboratory scale flotation tests for quartz particles of different sizes (< 20 µm, 20–38 µm, 38–75 µm, 75–106 µm, 106–150 µm, 150–212 µm) with an ether amine collector at different dosages were conducted in batch mode by using a bottom-driven mechanical flotation cell. An underwater loudspeaker was placed in the flotation pulp phase. The solids concentrations tested were 5% and 20% by weight. The results showed that acoustic sound (at 375 Hz and 77 decibels) increased the flotation recovery by at least 6% over a broad particle size range (i.e. 20–212 micron). The results also suggested applying acoustic sound in a flotation system can improve flotation recovery to a larger extent at a lower reagent dosage. An advantage of having the loudspeaker immersed in the pulp phase rather than in air above the flotation cell was the substantially reduced noise level. The present study provides a potential approach for improving flotation performance and reducing the chemical reagent consumption in flotation cells.

A novel route to the synthesis of α-Fe2O3@C@SiO2/TiO2 nanocomposite from the metal-organic framework as a photocatalyst for water treatment

In this study, an attempt was made to synthesize metal-organic frameworks (MOFs) based magnetic iron particles as photocatalysts for textile dye wastewater. Improvement strategy was a novel two-step dry method without using conventional methods to eliminate the consumption of chemical reagents. First, the heterogeneous photocatalyst of Fe-MOFs derived magnetic carbon nanocomposite with carboxylic acid surface functional groups (Fe@C–COOH) was achieved. Next, the α-Fe2O3@C@SiO2/TiO2 was successfully synthesized followed by a sol-gel method to coat the SiO2 shell and a solvothermal method to coat the surface of the intermediate TiO2 particles. The as-synthesized nanocomposite materials were characterized and physicochemical analytical equipment. Further, the investigation on magnetic photocatalytic nanocomposite α-Fe2O3@C@SiO2/TiO2 performance of dye degradation and photocatalytic activity on Reactive yellow 145 (RY145), using as an indicator was conducted. The as-synthesized nanocomposite particles were characterized using X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), X-ray energy dispersive spectroscopy (EDX), and scanning electron microscopy (SEM) techniques. The structural characterization of the as-synthesized materials proved that these methods generate oxygen-containing functional groups, such as, –OH, –CO, and –COOH, which increases the polarity and hydrophilicity of the photocatalyst. The photocatalytic oxidation of RY145 dye under UVc light was discussed by the apparent first-order reaction rate and the kinetic model of the Langmuir-Hinshelwood followed a better fitting. The optimal performance of the composite is at pH = 2, 15 mg/100 mL of photocatalyst dose, 150 mg/L concentration of the dye RY145 at 25 °C temperature under UVc lamp irradiation for 90 min, and with the apparent reaction rate constant was 0.0165 min−1. The thermodynamic analysis of activation parameters computed by the Eyring model and based on transition state theory (TST), an endothermic reaction with a positive value for Δ‡Ho (50.16 kJ mol−1) and a negative value for Δ‡So (−153 J/mol K) both contribute toward achieving positive values for Δ‡Go and a nonspontaneous process. The proposed α-Fe2O3@C@SiO2/TiO2 demonstrated a high capability of photocatalytic degradation up to 97% after five successive cycles at the optimal condition compared to that of Fe3O4@C (18.74%) and Fe@C–COOH (77.9%) without reusability.

Development of a green miniaturized quick, easy, cheap, effective, rugged, and safe approach in tandem with temperature-assisted solidification of floating menthol droplet for analysis of multiclass pesticide residues in milk.

A new green miniaturized quick, easy, cheap, effective, rugged, and safe approach was developed and used for the extraction of multiclass 16 pesticides in milk before gas chromatography analysis. The miniaturization of method reduced the consumption of chemical reagents and samples. Magnetic three-dimensional graphene was used as sorbent in the clean-up step. Choline chloride:lactic acid (1:2) natural deep eutectic solvent was used as desorption solvent. Temperature-assisted solidification of floating menthol drop was executed for preconcentration of analytes. The method parameters including sorbent, desorption solvent, sorption and desorption times, menthol amount, pH, and ionic strength were optimized. The limit of quantification and linear range were 0.03-0.38and 0.03-250μg/kg, respectively. The accuracy was assessed by recovery evaluation at the spike levels of 50 and 100μg/kg, in the range of 61-119%, with relative standard deviations within 2.1-18.2%. The method was applied to the analysis of pasteurized low and high-fat bovine milk, and various pesticide residues were detected in the concentrations range of 1.24-4.68 μg/kg. Finally, the greenness of the procedure was evaluated using the Analytical Eco-Scale. This work represents the first application of hybrid miniaturized extraction/preconcentration using a natural deep eutectic solvent and menthol to analyze pesticides.

A simple acoustofluidic device for on-chip fabrication of PLGA nanoparticles.

Miniaturization of systems and processes provides numerous benefits in terms of cost, reproducibility, precision, minimized consumption of chemical reagents, and prevention of contamination. The field of microfluidics successfully finds a place in a plethora of applications, including on-chip nanoparticle synthesis. Compared with the bulk approaches, on-chip methods that are enabled by microfluidic devices offer better control of size and uniformity of fabricated nanoparticles. However, these microfluidic devices generally require complex and expensive fabrication facilities that are not readily available in low-resourced laboratories. Here, a low-cost and simple acoustic device is demonstrated by generating acoustic streaming flows inside glass capillaries through exciting different flexural modes. At distinct frequencies, the flexural modes of the capillary result in different oscillation profiles that can insert harmonic forcing into the fluid. We explored these flexural modes and identified the modes that can generate strong acoustic streaming vortices along the glass capillary. Then, we applied these modes for fluid mixing using an easy-to-fabricate acoustofluidic device architecture. This device is applied in the fabrication of poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles. The acoustic device consists of a thin glass capillary and two polydimethylsiloxane adaptors that are formed using three-dimensional printed molds. By controlling the flow rates of the polymer and water solutions, PLGA nanoparticles with diameters between 65 and 96 nm are achieved with polydispersity index values ranging between 0.08 and 0.18. Owing to its simple design and minimal fabrication requirements, the proposed acoustofluidic mixer can be applied for microfluidic fluid mixing applications in limited resource settings.

INCREASED EFFICIENCY OF LEACHING OF RADIONUCLIDES, HEAVY AND RARE METALS FROM SOILS AND WASTES OF MOUNTAIN AND TECHNOLOGICAL MANUFACTURES

The article considers the methods of multiple and multi-stage leaching, as well as leaching in countercurrents with solutions that allow to transfer to a water-soluble state of the required amount of highly sorbable compounds, such as radionuclides, heavy and rare metals from soils, rocks and wastes of mining industries. The developed methods of calculation are presented, allowing due the choosing of optimal methods and parameters to reduce the consumption of solutions and increase the concentration of extracted elements in them. It has been established that the most promising methods of extraction are multistage leaching and exchange in countercurrents of the leaching solution and the material to be processed.&#x0D; The removal of radionuclides from soils and the extraction of rare metals from mining waste can be carried out by leaching, which requires a large consumption of chemical reagents. Therefore, it becomes necessary to identify the optimal leaching parameters by mathematical modeling. With this aim, the article proposed methods to reduce the consumption of leaching solutions, and determined the optimal parameters of leaching under specified conditions. For all the methods considered, analytical solutions are given that allow calculating the degree of purification from the extracted compounds, the consumption of the leaching solution and its concentration. А system of equations for multi-stage leaching has been solved. It was found that with a distribution coefficient of 5, in order to achieve a purification degree of 10 %, 3 times less solution will be consumed with four-fold leaching than with one-time leaching, and with multistage&#x0D; leaching, 9 times less.

Unveiling Sodium Ion Pollution in Spray-Dried Precursors and Its Implications for the Green Upcycling of Spent Lithium-Ion Batteries.

Unclear impurity pollution is one of the key scientific problems that limit the large-scale production of new lithium-ion batteries (LIBs) from spent LIBs. This work is the first to report the pollution path, pollution degree, and solution method of sodium ions in the recycling process of spent LIBs in the real world. The results show that sodium ions can intrude into the precursor particles to form crystalline salts with the anion of the leaching acid that cover the transition metal elements, thereby resulting in a failed precursor. Specifically, the intrusion of sodium ions will produce a variety of pollutants containing metal oxide bonds, such as Na-O, NaO2, and Na+-O2, on the precursor surface. These active lattice oxygen will further adsorb or react to form organic oxygen, chemical oxygen, and free oxygen, which will highly deteriorate the surface cleanliness. Strictly controlling the consumption of sodium salt in each step and using ammonia instead of NaOH for pH regulation can effectively solve sodium ion pollution to prepare high-quality battery precursors. It reveals that for the green upcycling of spent LIBs, we should strengthen the design of the recycling process to reduce the consumption of chemical reagents, which will produce unexpected secondary pollution.

High‐performance water purification and desalination by solar‐driven interfacial evaporation and photocatalytic VOC decomposition enabled by hierarchical TiO 2 ‐CuO nanoarchitecture

Solar-driven interfacial evaporation for clean water generation has drawn significant attention as a promising and environmentally friendly avenue to tackle the global issue of water scarcity. The collected condensate can be free from most pollutants and impurities of diverse undrinkable water sources, such as heavy metals, organic dyes, minerals, and salts. However, when water is contaminated by volatile organic compounds (VOCs), this approach is ineffective because VOCs also evaporate and even can be enriched in the condensate. Here, we demonstrate TiO2-loaded CuO nanowire-covered Cu foam (TiO2-CuO-Cufoam) for efficient solar-driven interfacial evaporation and synchronous removal of VOCs via photocatalytic degradation. The TiO2-CuO-Cufoam nanoarchitecture possesses high solar absorption, quasi-one-dimensional water pathway, super-hydrophilicity for ultrafast water transport, long-term stability, and potential for cost-effective and scalable production for both VOC removal and desalination, meeting World Health Organization potable water standards. Our TiO2-CuO-Cufoam evaporator simultaneously demonstrates high solar evaporation efficiency of 86.6% and efficiency of 80.0% for the removal of VOCs under one sun (i.e., 1 kW m−2). This result may open new opportunities for energy-efficient, clean water generation from real-world water sources using solar energy. Novelty Statement TiO2-loaded CuO nanowire-covered Cu foam (TiO2-CuO-Cufoam) was obtained through the facile and green synthesis process. The TiO2-CuO-Cufoam nanoarchitecture possesses high solar absorption due to surface nanostructuring, quasi-one-dimensional water pathway for localized thermal management, super-hydrophilicity for ultrafast water transport, TiO2-CuO heterojunction for enhanced photodegradation of VOCs without consumption of chemical reagents, long-term stability, and potential for cost-effective and scalable production. The nanoarchitecture is employed for clean water generation from real-world water sources.

Solar-assisted lithium metal recovery from spent lithium iron phosphate batteries

Lithium iron phosphate (LiFePO4) batteries have been considered to be an excellent choice for electric vehicles and large-scale energy storage facilities owing to their superiorities of high specific energy, low cost, excellent thermal safety, and long lifespan, leading to numerous scrap batteries. The lithium recovery from spent LiFePO4 batteries could be an alternative to relieve the shortage of resources and prevent the environmental pollution. However, traditional lithium recycling methods are limited in the practical application owing to the enormous consumption of chemical reagents and inevitable secondary pollution. Here we demonstrate a unique solar-assisted flow-through electrolysis method based on a TiO2 photoelectrode with efficient redox shuttles for lithium metal recovery from spent LiFePO4 batteries. The photovoltage generated on the TiO2 photoelectrode compensated the electrolysis potential, resulting in electric energy saving of 20.37% for lithium metal recovery. During the solar-assisted electrolysis process, metallic lithium could be instantaneously deposited on the copper foil avoiding secondary pollution. Moreover, the consumption of the I– solution was minimal via a close-loop flow-through regeneration reaction. 38.37 μg lithium metal was deposited with the energy consumption as low as 12.90 Wh g–1. It is worth noting that the lithium recovery from industrial spent LiFePO4 powders achieved a high recycling efficiency of 97.64%. This work provides a new simple but efficient way to recover lithium metal from spent LiFePO4 batteries.