Separation Efficiency Research Articles

Construction of AgI/NH2-MIL-125(Ti) heterojunction: Efficient degradation of organic pollutants in water by visible light response

Photocatalytic technology is an effective means to convert clean solar energy into green chemical energy, which has broad application prospects. Metal-organic framework (MOFs) composites have been widely used to remove pollutants from water. In this paper, the photocatalytic effect of NH2-MIL-125(Ti)[NM125(Ti)] photocatalyst with different AgI content on pollutants in water under visible light irradiation were studied. The successful preparation of AgI/NH2-MIL-125(Ti) photocatalyst was proved by the characterization of the physical and chemical structure of the composite material. When the dosage of AgI is 0.5 mmol, the removal rate of TC by AgI/NH2-MIL-125(Ti) is the highest (82 %). In addition, the photoelectrochemical test also proved that AMNT-0.5 mmol photocatalyst has higher electron-hole separation efficiency. After five cycle tests, the composite photocatalyst of ANMT-0.5 mmol still has good stability. The enhancement of the performance of ANMT-0.5 mmol photocatalyst can be attributed to: (i) the introduction of AgI increases the absorption of visible light in the composite; (ii) The close relationship between AgI and NM125(Ti) accelerates the separation of electron-hole pairs, thus improving the photocatalytic performance.

Heterophase structure of ZnSnO3 (rhombohedral and orthorhombic) for efficient dye degradation and N2-to-NH3 conversion via piezocatalysis and piezo-photocatalysis

Fabricating heterophase junctions proves to be an efficient strategy for achieving efficient charge separation and enhancing the catalytic activity of photocatalysts. Surprisingly, this approach is rarely utilized in the field of piezocatalysis. In this work, a novel ZnSnO3 heterophase junction catalyst was fabricated by combining rhombohedral (R-ZnSnO3) and orthorhombic (O-ZnSnO3) phases for efficient piezo and piezo-photocatalytic RhB degradation and N2 fixation. The piezocatalytic RhB degradation rates of ZnSnO3 heterophase catalysts are 5.6 and 3.6 times higher than those of O-ZnSnO3 and R-ZnSnO3, respectively, with similar enhancements observed in piezocatalytic N2 fixation. The coupling of R-ZnSnO3 and O-ZnSnO3 does not increase the piezoelectric properties; however, an S-scheme structure formed at the interface. Under the combined effects of band bending, interface electric fields, and Coulomb attraction, electrons and holes migrate and achieve effective spatial separation. This result supports the energy band theory over the induction charge theory, contributing to the ongoing debate in piezocatalytic mechanisms. Electrochemical analyses and piezo-photocatalytic tests further indicate that ZnSnO3 heterophase junctions exhibit a synergistic effect between piezocatalysis and photocatalysis. This synergy can be attributed to the complementary effects of photoinduced carrier generation and piezoelectric field-assisted carrier separation. Hydroxyl radicals, superoxide radicals, and holes serve as the primary active species responsible for piezocatalytic RhB degradation through a mechanism similar to photocatalysis. Theoretical calculations reveal that the Sn site on the surface of O-ZnSnO3 acts as the active site within the ZnSnO3 heterophase junction, providing valuable insights for future catalyst development. This work offers a deeper understanding of the synergistic mechanisms in piezo-photocatalysis, presenting a promising route for efficient environmental and energy applications.

Experimental and theoretical study of the photo-Fenton and photoelectrochemical properties of Ni doped FeOCl

In this work, Ni doped FeOCl (Ni-FeOCl) was synthesized by simple calcination method and used as a non-homogeneous phase catalyst for the photo-Fenton degradation of tetracycline (TC). Photo-Fenton experiments showed that the degradation of TC by Ni-FeOCl-10 was 93.3 % in 60 min under neutral solution, room temperature and visible light conditions. The incorporation of Ni led to lattice defects on the surface of FeOCl, which was favorable for the separation efficiency of the photogenerated electron-hole pairs (in agreement with the density-functional theory calculations). In addition, the TC removal efficiency decreased from 93 % to 82 % in five consecutive cycles, showing good structural stability. Finally, a possible mechanism for the degradation of TC by Ni-FeOCl catalysts was proposed on the basis of free radical trapping experiments. This research contributes fresh perspectives to the development of photo-Fenton catalysts and the treatment of antibiotic organic wastewater.

Sheep bone powder modified PVDF membrane for highlyefficient oil-in-water emulsion separation

BackgroundThe wetting properties and roughness modification of membrane surfaces are crucial for their application in emulsion separation. However, traditional membrane modification methods suffer from high cost, complex preparation, and secondary pollution. MethodsIn this study, a novel, simple, and economical interfacial engineering method was developed using tannic acid (TA), sodium alginate (SA), and sheep bone powder (BP) as raw materials. Through vacuum filtration, these materials were deposited onto polyvinylidene fluoride (PVDF) membrane to fabricate superhydrophilic/underwater superoleophobic filtration membrane (PDBS). BP induced surface roughness and wetting properties to the membrane, while preserving the porous structure of the substrate membrane. The complex formed by TA and SA encapsulated BP onto the surface of PVDF microfiltration membrane, enhancing its mechanical properties. Significant FindingsThe prepared membrane exhibited a membrane flux of 347 Lm−2h−1 bar−1 and a separation efficiency of 99.9 % for emulsified oil. Furthermore, after soaking in NaCl solution for 30 h, the membrane still showed excellent stability. Therefore, this study developed a new membrane surface modification strategy with promising application prospects in oily wastewater treatment.

Self-assembled perylene diimide decorated g-C3N4 heterojunction catalyst with strong interfacial charge transfer through π-π interaction for efficient boosted photocatalytic degradation of tetracycline

Perylene diimide (PDI) organic material and its derivatives as photocatalysts possesses excellent charge separation efficiency and are renowned as among the top n-type organic semiconductors capable of absorbing visible light owing to their narrow band gap (∼1.69 eV). Heterojunction photocatalysts with efficient electron transfer and excellent photocatalytic performance are of great significance for the degradation of organic compounds in the environment. In this work, a series of heterojunction catalysts (CNPDI) with robust interfacial charge transfer via π-π interaction were prepared using g-C3N4 and different mass ratio of the self-assembled PDI as precursors, subsequently utilized as efficient visible-light-driven photocatalysts for the degradation of organic tetracycline. SEM and TEM results indicated that porous CN was completely wrapped around PDI nanorod structure formed by strong π-π interactions. In the presence of activating potassium peroxymonosulfate (PMS) substances, the kinetic rate constant of the CNPDI photocatalytic system clocked in at 0.026 min−1, marking 2.36 fold increase compared to the original CN (0.011 min−1). The bolstered degradation performance was attributed to the built-in potential formed by the self-assembled PDI and CN, promoting the separation of electron-hole pairs and redistribution of charge density in the interface region. This work presents a useful insight into the crafting of PDI-based heterojunction photocatalysts for degradation environmental pharmaceutical pollutants.

Analysis of cyclone separator solutions depending on spray ejector condenser conditions

The core design strategy for minimizing CO2 emissions in gas power plant entails combining a spray ejector condenser (SEC) and separator to accomplish steam condensation and CO2 purification. This innovative process involves direct-contact condensation of steam with CO2, facilitated by interaction with a subcooled water spray, along with a cyclone separator mechanism intended for generating pure CO2. The investigation of the SEC section, both experimentally and analytically, provides crucial insights into its operational dynamics. Given the susceptibility of cyclone efficiency to fluctuations in SEC conditions, this research endeavors to examine the impacts of CO2 volumetric flow rate and droplet break-up within the SEC on the separation efficacy of the cyclone separator. Additionally, the impact of cone size on the performance of the cyclone has been investigated. Here, a three-dimensional, transient, and turbulent cyclone separator is numerically simulated using Ansys Fluent 2021 R1. The Reynolds Stress Model is employed to simulate turbulent flow, while a mixture model is utilized to replicate swirl two-phase flow within the separators. The findings revealed that reductions in steam and CO2 flow rates were associated with a decrease in outlet temperature but an increase in SEC inlet temperature, leading to a rise in temperature difference and heat transfer rate. Furthermore, an augmentation in cyclone cone size (from 0.2 to 0.5 m) resulted in enhanced separation efficiency (from 77.30 % to 80.98 %) alongside an elevation in pressure drop (from 6.08 Pa to 10.91 Pa), suggesting a compromise between CO2 purification and energy consumption. Additionally, elevated CO2 flow rates induced a rise in pressure drop and separation efficiency, ultimately achieving maximum efficiency at a rate of 24 gs. Moreover, the exploration into droplet breakup manifesting in a boost in separation efficiency from 50.98 % to 100 % across droplet diameters ranging from 1 to 20 μm.

Recycling of UO22+ expanded by metal-organic framework bearing pyrazinoquinoxaline tetracarboxylic acid: pH fluorescence sensing and photocatalytic activity

With the wide application of nuclear energy, the recycling of uranium resources and environmental protection have become the focus of scientific research and industrial attention. Uranyl ions have better electronic configurations and optical properties, but poor energy utilization and recycling as ionic states. Drawing on the structural features of Metal-Organic Frameworks (MOFs), the combination of UO22+ nodes with photoactive ligands should be able to effectively regulate the energy level matching between metal nodes and conjugated ligands, improve the electronic configuration and energy band structure, and thus produce better photoresponsive functional properties. In the present work, an example of a novel two-dimensional layered U-MOF was constructed by self-assembly, which utilizes pyrazinoquinoxaline tetracarboxylic acid. Due to the stable coordination structure, matched energy levels and synergistic photoresponsive behavior of UO22+ with pyrazinoquinoxaline ligands, U-MOF enables fluorescence sensing response in aqueous solution at pH=2–5, 9.5–12 and fluorescence quenching detection of a wide range of substrates. Theoretical calculations reveal that the interaction of the hydrogen ion with pyrazinozinoquinoxaline moiety extends the degree of conjugation of the moiety. Meanwhile, the interaction of hydroxide ions with pyrazinozinoquinoxaline groups elevates the highest occupied molecular orbital (HOMO) energy level, which significantly affects the photoelectric properties of U-MOF. In addition, U-MOF can be used as a photocatalyst to realize the conversion of benzylamine to N-benzylbenzylideneimine by oxidation under mild conditions. The effective electron transfer between uranyl ions and ligands ensured the photogenerated electron-hole separation efficiency and enhanced the energy utilization. Therefore, the related results of U-MOFs illustrate the practicality of introducing UO22+ nodes into MOFs to construct novel photoresponsive materials, which provides a new way for the efficient recycling and utilization of uranium resources.

Strong electron coupling between amorphous WP and MoSe2/ZnCdS S-scheme heterojunction for enhanced wide spectrum photocatalytic hydrogen production

The photogenerated carrier separation efficiency is a key factor for limiting the photocatalytic activity. In this work, an amorphous WP modified S-scheme MoSe2/ZnCdS (WP/MoSe2/ZCS) heterojunction was synthesized for wide spectrum photocatalytic hydrogen production. After initially forming an S-scheme heterojunction by compositing ZnCdS with nano flower-shaped MoSe2, the light absorption ability of the bimetallic sulfide was significantly enhanced, along with an improved photogenerated carrier separation efficiency. Additionally, the introduction of WP as a co-catalyst not only provides more active sites for photocatalytic reactions, but also enhances the photogenerated electrons transfer through the synergistic effect of strong electronic coupling and S-scheme MoSe2/ZCS heterojunction.The significant enhancement of photocatalytic hydrogen evolution activity of 7％WP/MoSe2/ZCS reached 47.7 mmol g−1 h−1, which is 4.72 times higher than that of ZnCdS (10.1 mmol g−1 h−1). The strong electron coupling effects and S-scheme electron ransfer mechanism was proved by in-situ XPS and Density functional theory (DFT) calculations. This work provides a new strategy for the construction of high-efficiency photocatalyst with strong electronic coupling.

PH independent adsorption: Reusable zinc-ferrite nanospheres for the selective recovery of dyes from binary mixtures

Efficient separation of colorant pollutants is a formidable challenge, prompting research into innovative materials. We developed zinc-ferrite nanoparticles via the Microwave-Assisted Solvothermal Technique (MAST), exploiting judicious solvent compositions to enhance Lewis's acidity. Upscaling to gram batches yielded nanoparticles with a higher specific surface area (149 m2g−1). These nanoparticles demonstrated selective separation of dyes from binary mixtures, including Orange-G (OG), Fluorescein-Sodium (FSS), and Methyl-Orange (MO), with their high sorption rate fitting to the pseudo-second-order kinetic model. Langmuir isotherm for OG and MO were observed with respective adsorption capacity (qm) of 94.12 mg/g, 104.28 mg/g, whereas FSS more likely matched Sips isotherm with qm = 124.31 mg/g at natural pH in room temperature (27 °C). Desorption, reliant on solution pH and OH− ions, enabled efficient regeneration and multiple reuses without significant efficiency loss over five reuse cycles. Remarkably, selective separation was independent of surface charge and remained effective across a wide pH range and in the presence of common anions, namely I−, NO3−, C2H3O2− routinely encountered in dye effluents. This ecologically safe, scalable adsorbent offers a promising solution for expensive dye recovery.

Determination of aconitum alkaloids in acute poisoning case by electromembrane extraction

In this work, electromembrane extraction (EME) was used for the first time to separate aconitine (AC), mesaconitine (Mes-AC) and hypaconitine (Hyp-AC) from biological samples and Chinese herbal medicines. Efficient EME of polar and high molecular weight aconitine alkaloids from different sample matrices was achieved with the solvent of 1-ethyl-2-nitrobenzene (ENB). Under the optimal EME conditions, EME provided recoveries for all targets in the range of 72%–74 %, 85%–103 % and 92%–94 % for whole blood, urine and aqueous samples. The proposed EME systems combined with LC-MS/MS and HPLC-UV were evaluated using different sample matrices, and the methods displayed satisfactory analytical characteristic including negligible matrix effect. The LOD and LOQ of AC, Mes-AC, and Hyp-AC by EME-LC-MS/MS were in the range of 0.002–0.068 ng/mL and 0.005–0.228 ng/mL respectively. The LOD and LOQ of AC, Mes-AC, and Hyp-AC by EME-HPLC-UV were in the range of 0.06–0.26 μg/mL and 0.20–0.86 μg/mL, respectively. The coefficient of determination, R2-value was ≥0.9926 for all cases, and the accuracy in the linear ranges was in the range of 91%–111 %. Finally, the method was successfully applied for the qualitative and quantitative analysis of AC and Mes-AC in the whole blood and herbal medicine dreg samples from an actual forensic case, and poisoning by aconitum alkaloids was identified as the cause of death. Therefore, we believe that EME could be a powerful tool to identify poisoning, and EME has great potential for efficient separation of polar and high molecular weight substances. These are of great importance in the fields of but not limited to forensic science, Traditional Chinese Medicine and clinics.

Homogenate-ultrasonic pretreatment followed by microwave hydrodistillation of essential oil from rosemary (Rosmarinus officinalis L.) leaves: Kinetic, chemical composition, and biological activity

Rosemary (Rosmarinus officinalis L.) is an important cash crop, and its essential oil (EO) has been widely used in food, chemical, pharmaceutical and other industries. The efficient and green separation of rosemary essential oil (RO) can provide technical support for its application and realize the high-value utilization of rosemary resources. In this work, RO was separated by a modified homogenate-ultrasonic pretreatment followed by microwave hydrodistillation (HUP-MHD) technique. The influencing parameters involved in the homogenate, ultrasonic pretreatment and microwave hydrodistillation processes were screened and optimized by single factor experiment and further response surface experiment (BBD), which derived the RO yield and eucalyptol percentage of 1.35 ± 0.05% and 36.73 ± 1.18%, respectively. After comparison with other techniques in terms of RO yield, separation efficiency, and chemical composition, the HUP-MHD method showed obvious advantages in the separation of RO and oxygenated components (eucalyptol, borneol etc.). In addition, the antioxidant activity (DPPH and ABTS) and antifungal activity of RO from different techniques were measured, the results pointed out that the HUP-MHD method could separate RO with higher biological activity. Therefore, the HUP-MHD has the advantages of short time consumption, high efficiency, and safety in the separation of EO, which provides a theoretical basis for sufficiently separating EO from rosemary and other natural plant and crop materials.

Effective charge separation in CdS@PANI heterostructure for ultrafast visible light-driven photocatalytic reduction of uranium(VI)

The efficient treatment of uranium-containing wastewater provides guarantee for sustainable development of nuclear energy. In this work, a heterogeneous interface structure for photocatalytic reduction of U(VI) was proposed by in-situ decoration of cadmium sulfide (CdS) nanoparticles on polyaniline (PANI) nanorods. The strong coupling between CdS and PANI precisely modulated the interface electronic structure, which promoted the photogenerated charge separation. Multiple spectroscopic characterizations revealed that the interfacial charge polarization with the electrons gathering at the CdS surface and the holes gathering at the PANI, facilitating the performance of photocatalytic reduction of U(VI) under visible light irradiation. The optimal CdS@PANI-10 shows ultrafast U(VI) reduction with efficiency of over 96 % in 5 min. Moreover, the photocatalytic reduction of U(VI) over CdS@PANI-10 can also be activated by direct natural sunlight irradiation. The improvement of catalytic activity of CdS@PANI nanocomposite is due to faster charge separation and migration at the interface between CdS and PANI, as well as the formation of Type-II heterojunction, which was also beneficial for suppressing the CdS photocorrosion. This work introduces a potential strategy to design advanced photocatalysts with efficient electrons and holes separation toward practical application in uranyl ion conversion.

Improved naphthalene photodegradation rate of CN/Pt-P25 photocatalyst by effectively tuning Pt chemical states via H2 secondary annealing

Photocatalytic technology holds promising prospects for remediating naphthalene pollution in water bodies. In this work, the CN/Pt-P25 photocatalyst was successfully prepared via photodeposition combined with co-pyrolysis methods, and employed for naphthalene photodegradation under simulated sunlight. The chemical state of Pt was found to have a significant impact on the photocatalytic activity. H2 secondary annealing effectively tuned Pt chemical states, increasing the proportion of Pt0 species on the CN/Pt-P25 photocatalyst from 41.91 % to 62.24 %. The improved proportion of Pt0 species proportion led to a reduction in the bandgap, which induced changes in the band positions and notably enhancing the separation efficiency of photogenerated electron-hole pairs. Under simulated sunlight irradiation, (H2) CN/Pt-P25 photocatalyst achieved complete naphthalene photodegradation within 100 min. Thus, photocatalysts containing a high proportion of Pt0 species exhibited an improved performance in naphthalene photodegradation. These findings provide new insights into the application of photocatalytic technology for the remediation of PAHs.

All cellulose-based superwetting aerogel/wood composite with disordered/ordered pores structure for rapid emulsion separation

Rapid and efficient separation of oil from emulsions is critically required prior to addressing the global challenge of oily sewage, but most separation membranes encounter intractable challenges in terms of the trade-off effect between separation efficiency and flux, as well as the use of petrochemical feedstocks. Herein, an all-biomass wood/aerogel composite with a disordered/ordered structure was constructed by filling cellulose nanofibers aerogel into the intertubular cavities of delignified wood using cotton and wood as building blocks through a series of processes, including casting, regeneration, and freeze-drying. The parallel channels of wood and the porous structure of aerogel constitute the special disordered/ordered pores structure, which accelerates vertically oriented permeation and enhances emulsified droplets coalescence for demulsification. In addition, the aerogel/wood composite retains the inherent hydrophilicity of cellulose and exhibites excellent underwater superoleophobicity with an underwater oil contact angle of 159.6°, which is chemically stable and salt resistant. The unique disordered/ordered structure and superwettability of the aerogel/wood composite contribute to its exceptional separation efficiency (99.25 %) and high flux (2580 L·m−2·h−1) for the separation of oil-in-water emulsions when driven only by gravity. Additionally, the composite shows good utility and ease of cycling. These outstanding properties highlight its promising practical application in the oil-related industry.

UV-crosslinked SBS block copolymers via thiol-ene reaction for efficient absorption and removal of oil/organic solvents from water

With the urgent need for oil/organic solvents spills disposal, the development of new sorbents with low cost, high sorption capacity, good selectivity and reusability is required. In the current work, three-dimensional structured absorbents have been rapidly fabricated by ultraviolet (UV)-crosslinking of styrene-block-butadiene-block-styrene (SBS) copolymers via thiol-ene reaction in 60 s, using poly-(mercaptopropyl)methylsiloxane (SMS) as crosslinker. The SBS-SMS absorbents were characterized by FT-IR, SEM, XRD, tensile strength, thermogravimetric, gel fraction and water contact angle analysis, which showed high tensile strength, good thermal stability, hydrophobicity, and acceptable gel content. The absorption capacity investigations were carried out in 7 types of organic liquids and 2 types of oils. The SBS-SMS0.005 exhibited the highest absorption performance in different organics, with the capacities of 74.6 g/g for dichloromethane, 20.1 g/g for kerosene, and 12.8 g/g for diesel oil, respectively. The impacts of sheet thickness on the absorption and desorption kinetics were studied, and the results showed that thinner absorbents illustrated faster absorption and desorption speed. Additionally, the SBS-SMS absorbents showed good selectivity and effectiveness in organic solvents/oil separation from water (separation efficiency > 93 %), well oil retention ability and oil desorption efficiency, floating properties, easy collection, as well as good reusability upon ten absorption-desorption cycles. The current SBS-SMS absorbents should have great potential in practical application for efficient oil/water separation as well as radioactive organic waste liquid treatment.

Development of superhydrophobic PVA/CNC nanofibrous membranes for enhanced oil-water separation

Effective oil–water separation is crucial for environmental purification and the remediation of oil pollution, yet current methods face limitations in efficiency, durability, and environmental impact. In this study, we aimed a green nanofibrous membrane with excellent oil–water separation efficiency, addressing the significant environmental challenge of separating oil from water in various states. For this purpose, polyvinyl alcohol (PVA)-based nanofibers were prepared by aqueous electrospinning. The mechanical strength of the nanofibers was reinforced by adding cellulose nanocrystals (CNCs). The surface of the nanofibers was modified with hexadecyltrimethoxysilane (HDTMS) to induce hydrophobicity, evidenced by the increase in contact angle from 44.41° to 133.19°, facilitating effective oil separation from various states, including dispersed, suspended, and emulsified states. The prepared PVA/CNC-HDTMS nanofiber showed 194 %, 539 %, and 407 % higher tensile strength, yield strength, and Young’s modulus than PVA nanofibers, respectively. The oil sorption capacity of the nanofibers varied widely from 17.01-113.76 g/g, which is strongly influenced by the viscosity and volatility of the oil species. The durability and reusability of the nanofibers were well maintained, even after being reused more than 10 times without morphological deterioration. In separating oil–water mixtures, the nanofibers maintained a high flux of 40,039 L/m2h and a separation efficiency of 99.2 % under pressurized conditions. Additionally, the nanofibers achieved a separation efficiency of 98.5 % in oil–water emulsion states.

MoC nanoparticles embedded in superior thin g-C3N4 nanosheets for efficient photocatalytic activity

Photogenerated charge carrier transfer efficiency in graphitic carbon nitride (g-C3N4) based heterostructures depended strongly on the interface nature. In this paper, MoC nanoparticles less than 5 nm were implanted in superior thin g-C3N4 nanosheets to create high charge carrier separation and transfer efficiency. Cubic MoC in N-doped graphitic carbon was first fabricated using dicyandiamide and ammonium molybdate tetrahydrate at 800 °C. The MoC nanoparticles were homogeneously implanted in g-C3N4 nanosheets by further thermal polymerization of bulk g-C3N4 prepared using melamine and MoC/C composites to create a Schottky junction which was confirmed by band gap analysis and free radical capture test. Melamine and dicyandiamide also play important role to create highly efficient catalysts. The MoC nanoparticles revealed fine crystallinity. A well-developed interface between MoC and g-C3N4 was observed. Because of high conductivity of MoC, well-developed interface, and co-catalyst role of MoC, the MoC/g-C3N4 junction exhibited ideal photocatalytic activity for dye degradation and water splitting. The kinetic constant rate of Rhodamine B degradation using a MoC/g-C3N4 sample created by optimized conditions was 0.061 min−1 which was 8.7 times of that of pristine g-C3N4 nanosheets. In the case of without co-catalyst addition, the photocatalytic hydrogen generation rate using this composite sample was 233.0 μmol g−1 h−1 which was 15.2 times of that of initial g-C3N4 nanosheets. These results supply an efficient approach for the first time to homogeneously distribute small cubic MoC nanoparticles in superior thin g-C3N4 nanosheets to construct heterostructures and greatly reduce photogenerated charge carrier recombination.

Phase transformation and roasting kinetics of CIGS waste in air atmosphere

Copper indium gallium diselenide (CIGS) solar cells produce a lot of CIGS waste in the production process. TAK method was used to study the roasting kinetics of CIGS waste to separate and recovery harmful elements of environment. The oxidation of CIGS is different for different heating rates, oxides of various metal elements are formed at lower roasting rates, but InGaCuO4 is formed at higher roasting rates. The E of each oxidation process was obtained by FWO method and KAS method respectively. The E of element In at lower roasting rates are 104.43 KJ/mol and 112.17 KJ/mol. The E of Ga are 105.86 KJ/mol and 113.52 KJ/mol. The E of Cu are 134.46 KJ/mol and 141.35 KJ/mol. The E of InGaCuO4 were 33.45 KJ/mol and 45.53 KJ/mol. The model function of CIGS waste reaction was determined by Malek method analysis. The oxidation mechanism model of element In is No.39 and No.40 functions: Exponential law. The oxidation mechanism model of the element Ga is function No.37: Chemical reaction control, and the oxidation mechanism model of the element Cu is function No.9:3-D diffusion Zhuraalev-Lesokin-Tempelman. The mechanism model of CIGS waste higher roasting rates in second stage is function No.9:3-D diffusion Zhuraalev-Lesokin-Tempelman. The results show that the heating rate of roasting process obviously affects the oxidation behavior of CIGS waste, so it is of great significance to control the heating rate to oxidizes CuO, Ga2O3 and In2O3 in CIGS waste, and to improve the separation and recovery efficiency of elements in the subsequent process.

D/A heterojunction photocatalysts interspersed onto biochar to couple photocatalysis and adsorption for visible light-responsive efficient removal of pollutants

Phenol has various applications in industry, due to its hazardousness, solubility, and volatility, it persists in water and poses a risk to human health. People are excited by the progress of photodegradation technology that facilitates water pollution treatment. The effect of side-chain engineering is proven to enhance photodegradation performance by improving optoelectronic properties. Therefore, here is a strategy that introduces functional groups to change the electron cloud density, achieving excellent optoelectronic properties evidenced by efficient exciton dissociation, separation, and fine-tuned energy level. Subsequently, by coupling of photocatalysis and adsorption, the donor/acceptor (D/A) heterojunction photocatalysts (PBDB-T: BTTIC-TT, PBDB-T: BTTIC-Ph) are designed via loading on coconut-shell carbon to process phenol. The results indicate that the champion photocatalyst PBDB-T: BTTIC-TT possesses superior optoelectronic properties, which can be attributed to the stronger electron-withdrawing ability of thieno[3,2-b]thiophene than benzene. Consequently, the synergistic efficiency of adsorption and photocatalysis of phenol (10, 20 mg/L) are removed within 10 mins over 90 % which is still valid after twenty cycles. Surprisingly, a high concentration of phenol (100 mg/L) also exhibited excellent removal efficiency of over 80 % within 60 min.

Enhanced degradation of dyes using a novel CuS/g-C3N4/rGO ternary composite catalyst: Synthesis, characterization, and mechanistic insights

This work reports the synthesis, characterization, and application of a novel CuS/g-C3N4/rGO ternary composite catalyst for the enhanced degradation of dyes. CuS nano-flowers, and the composites CuS/rGO, CuS/g-C3N4, and CuS/g-C3N4/rGO were synthesised using the hydrothermal method and characterized by XRD, SEM, FTIR, UV–Vis, and PL spectroscopy. These samples were studied for the photocatalysis of Malachite green (MG) and Murexide (MX) dyes under visible light. Among the four samples, the CuS/g-C3N4/rGO ternary composite has shown 97.05 % and 72.16 % degradation for MG and MX dyes respectively at the timeframe of 70 min. The results are obtained for a little catalytic load of 10 mg and a higher dye concentration of 25 ppm. Detailed mechanistic insights into the dye degradation process were obtained through the analysis of band-edge potential supported by Impedance and PL spectra. The enhancement in the photocatalytic property of the ternary composite can be attributed to the synergistic effects between individual components, including enhanced light absorption, efficient charge separation and improved catalytic activity. The obtained results demonstrate that the novel ternary composite, CuS/g-C3N4/rGO is a promising catalyst for the degradation of MG and MX dyes in wastewater treatment applications.