Industrial Organic Solvents Research Articles

Reconfiguring closed-loop desorption for industrial solvent recycling by retaining post-condensation volatile organic compounds

Massive emissions of volatile organic compounds (VOCs) from industrial solvent evaporation have exacerbated atmospheric pollution. As high-value pollutants, VOCs can be concentrated and condensed into liquid solvents for reuse instead of destructive elimination, minimizing environmental threats and treatment costs. However, classical thermal swing adsorption (TSA) using nitrogen as the purge gas are inclined to be in closed form to economize on nitrogen, which results in desorption residues at the outlet of the adsorber and leads to environmental risks. In this study, one-step closed-loop desorption (OCD) and two-step closed-loop desorption (TCD) were proposed for industrial solvent recovery by reconfiguring TSA and condensation to improve desorption efficiency and recovery performance. A detailed mathematical model was developed and validated experimentally to describe dynamic behaviors of closed-loop desorption. The results showed that the standby adsorber connected to the thermal desorption process effectively retained the post-condensation VOCs and reduced the desorption residual for the re-absorption efficiency. By using the orthogonal experimental design, desorption temperature, condensation temperature, and feed concentration were proved to be more significant on recovery capacity than packing height and purge velocity. A broader feasible recovery domain was achieved by the TCD cycle, with an increase of 48.15 % compared to the OCD cycle at low feed concentrations. The OCD cycle was more energy-efficient, except in scenarios of low adsorption loading and low-grade energy sources. The findings provide new insights and promising approaches for achieving synergies between industrial exhaust treatment and organic solvent recovery.

Thermal decomposition study of 1,3-dioxolane as a representative of battery solvent

As industrial compounds and organic solvent, 1,3-dioxolane (C3H6O2) is used in lithium-ion batteries arousing extensive interest. The pyrolysis of C3H6O2 at 150 torr pressure was conducted in the temperature range of 743–1013 K. In order to quantify the major products, experimental measurements of the photoionization cross-section (PICS) and photoionization efficiency (PIE) for C3H6O2 were carried out by using synchrotron radiation photoionization mass spectrometry (SR-PIMS). Twenty-three intermediates were detected in pyrolysis of C3H6O2 including the newly observed ketene, acetaldehyde, ethenol, ethanol, dimethyl ether, diacetylene and 2-propen-1-ol which played important roles in developing mechanism. The H-abstraction of C3H6O2 by H, CH3 and OH radicals were studied via high level ab initio calculations. EStokTP code was used to find and calculate optimal geometries, vibration frequencies and intrinsic reaction coordinate (IRC) at the theory level of M06–2X/6–311+G(d,p). Conventional transition state theory (TST) was used and Rice-Ramsperger-Kassel-Marcus/Master Equation (RRKM/ME) was solved to obtain rate coefficients. For H-abstraction by H and CH3, the rates are increasing versus temperature, and rates of H-abstraction by OH show different tendency. These rate parameters were used to update the model of C3H6O2, which could well predict the ignition delay times (IDTs) in shock tube and oxidation data in jet stirred reactor (JSR) from literature. For the pyrolysis, H-abstraction reactions by H, CH3 and OH and unimolecular reactions contribute to solvent decay. Detailed pathways of C3H6O2 decomposition were also given and analyzed through this experiment and previous literature. The findings, including the experimental data and the calculations will assist to better understand pyrolysis characteristics of C3H6O2 as well.

Pyrrole adducts mediated mitochondrial dysfunction activates SARM1-dependent axon degeneration in 2,5-hexanedione-induced neuropathy

2,5-hexanedione (HD) is the γ-diketone metabolite of industrial organic solvent n-hexane, primarily responsible for n-hexane neurotoxicity. Previous studies have shown that the formation of pyrrole adducts (PAs) is crucial for the toxic axonopathy induced by HD. However, the exact mechanism underlying PAs-induced axonal degeneration remains unclear. Recently, Sterile α and toll/interleukin 1 receptor motif-containing protein 1 (SARM1) has been identified as the central executor of axon degeneration. This study was designed to investigate the role of SARM1-mediated axon degeneration in rats exposed to HD. Furthermore, the causal relationship between PAs and SARM1-mediated axon degeneration was further explored using Sarm1 KO mice. Our findings suggest that HD causes axon degeneration and neuronal loss in animals. Mechanistic studies revealed that HD activates SARM1-dependent axonal degeneration machinery. In contrast, Sarm1 KO attenuates motor dysfunction and rescues neuron loss following HD exposure. Interestingly, the PAs formed by the binding of HD to proteins primarily accumulate on mitochondria, leading to mitochondrial dysfunction. This dysfunction serves as an upstream event in HD-induced nerve injuries. Our findings highlight the crucial role of PAs formation in the major pathological changes during n-hexane poisoning, providing a potential therapeutic target for n-hexane neuropathy.

A facile preparation of high flux NaA zeolite membranes by direct secondary growth of wet gel layer

NaA zeolite membranes were first applied in industrial organic solvent dehydration in 1999. However, issues such as poor reproducibility, low flux, and high cost of NaA zeolite membrane preparation have hindered its industrial progress. In this work, a direct secondary growth of wet gel layer method is employed. Specifically, a wet gel layer is coated to the outer surface of the seeded support, which is then placed into the Teflon-lined autoclave without additional hydrogel inside. Under the conditions of conventional secondary growth (100 °C for 4 h), high flux NaA zeolite membranes can be prepared. The pervaporation performance in the 90 wt% ethanol/water solution is tested at 75 °C, showing the flux up to 4.59 kg m−2 h−1 and the separation factor above 10,000. The controlling factors involved in the preparation of high flux NaA zeolite membranes using the direct secondary growth of wet gel layer are investigated. It is found that the introduction method of the seed layer and wet gel layer, the size of the seed, the state of the gel, and the immersion time play significant roles in the formation of zeolite membranes with superior separation performance. This method provides a new idea for the preparation of high performance, low cost and reproducible zeolite membranes with prospects for industrial application.

Spatiotemporal distribution, source apportionment and health risk assessment of atmospheric volatile organic compounds using passive air samplers in a typical coastal area, China

To fully understand source characteristics and human health effects of atmospheric volatile organic compounds (VOCs), it is of great importance to implement long-term measurements, precise source apportionment and simulation. In this study, a 12-month measurement of VOCs was conducted in a coastal area in East China by a novel passive air sampler (PAS). A total of 28 VOC species, mainly in groups of aromatics and halohydrocarbons were observed. The monthly average concentrations of TVOC were as follows: industrial sites (154.10–727.19 μg m−3) > business sites (65.83–86.96 μg m−3) > residential sites (59.63–60.05 μg m−3) > background site (57.62 μg m−3). Their seasonal variation characteristics were: winter > spring > autumn > summer, which was more apparent at industrial sites due to human activities. Six VOC sources including industrial processes, organic solvents, dyeing, plastic synthesis, traffic emissions, and pesticides identified by the positive matrix factorization model compared favorably with the local emissions at industrial sites. Bromoform, hexachloro-1,3-butadiene, C1–C3 halogenated alkanes and benzene homologs could be the important indicators of industrial VOC emissions. The halohydrocarbons and aromatics were the major contributors to the ozone formation potential (OFP) and secondary organic aerosol potential (SOAP) in industrial areas, respectively. Both of OFP and SOAP have their maximum values in winter due to high VOC concentrations. Health risk assessment indicated that a high probability of non-carcinogenic risk (HI > 1) was in the region at 10 m height and 50m radius, and minor carcinogenic risk (CR > 10−6) was in the region at 70 m height and 1000 m radius. Among all the compounds, 1,2-Dibromo-3-chloropropane was the largest contributor with the individual HI value (17.99) and carcinogenic risk (5.34 × 10−3) at the peak. In this study, the PAS as a sampling tool was proven to be reliable and efficient for long-term measurements in coastal areas. It is worth to have further studies to promote passive sampling as an alternative to VOCs monitoring methods.

Durable LBL microcapsule-based sponges with superhydrophobic/super-oleophilic and photothermal behaviors for oil–water separation

Spills of marine oily pollutants and illegal discharges of industrial organic solvents have severely undermined the natural resources and ecological sustainability. Herein, a versatile and durable modified melamine sponge (MS) was fabricated by integrating with multilayered microcapsules (MCs) and chemical vapor deposition of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES), namely PFDTES@MCs@MS. The combination of giant microcapsules on the sponge structure imparts the rough surface micro-construction, accompanied by the hydrophobic modification, which enabled PFDTES@MCs@MS to exhibit superhydrophobic/super-oleophilic and self-cleaning capabilities. PFDTES@MCs@MS displayed outstanding oil–water mixtures or emulsions separation capabilities with the separation efficiencies more than 99%. Impressively, PFDTES@MCs@MS preserved mechanical and chemical durability in 100 recycle tests or chronic processes under harsh conditions. In addition, PFDTES@MCs@MS exhibited the remarkable uptake capacity of organic solvents or oils, and the adsorption amount of light or heavy oil was barely impacted with squeezing after the 50 times of circulation. Furthermore, the PFDTES@MCs@MS displayed antibacterial performance. Significantly, the PFDTES@MCs@MS showed superior photothermal conversion capability, the temperature of it increased dramatically to approximately 80 °C within 180 s under simulated sunlight from room temperature (about 25 ℃), and the flux of separating high-viscosity oils was significantly increased. This study presents a novel oil sorption and separation materials with excellent durability and repeatability, which establishes the foundation for the judicious design of innovative weapons to combat the challenging oil spills.

Polyamide thin film nanocomposite with in-situ co-constructed COFs for organic solvent nanofiltration

Organic solvent nanofiltration (OSN) is a novel membrane technology, it has great potential for organic solvent separation and purification due to its advantages of low energy consumption and mild operating conditions. High-performance OSN membranes are essential for OSN technology. Herein, we adopted a straightforward one-step in-situ co-polymerization procedure for the fabrication of a thin film nanocomposite (TFN) OSN membrane having a COFs-polyamide selective layer via doping the COFs reaction monomers, p-phenylenediamine (Pa) and 1,3,5-triformylphloroglucinol (Tp), into the aqueous m-phenylenediamine (MPD) solution and organic trimesoyl chloride (TMC) solution, respectively, during the interfacial polymerization (IP) process. With the ultra-low concentrations used in both MPD and COFs reactive monomers, the optimal TFN OSN membrane, TFN-100-75, achieves an ethanol permeance of 65.7 L m−2 h−1 MPa−1 and an Rhodamine B (RDB, 479 Da) rejection of 99.0%. Meanwhile, this OSN membrane has an ultra-smooth surface, corresponding to a roughness of only 2.9 ± 0.3 nm. Also, this membrane has larger porosity, average pore size, and surface pore density compared with the COFs-free thin-film composite (TFC) membrane. Besides, the TFN-100-75 membrane has a pure methanol and ethanol permeance of 184.3 and 105 L m−2 h−1 MPa−1, respectively, and a molecular weight cut-off (MWCO) of about 362 Da. The TFN-100-75 membrane achieved an rifampicin rejection of above 99% during the separation of rifampicin/ethanol solutions with different concentration as well as the continuous concentration experiment, demonstrating its potential in pharmaceutical separation and purification. During a long-time variable temperature immersion test in pure N,N-dimethylformamide (DMF) at 25 °C for 32 days and then at 80 °C for 24 days, the TFN-100-75 membrane demonstrates superior solvent resistance, where the RDB rejection decreased only by 2%, from 99.0% to 97.0%. The TFN OSN membrane fabricated by the simple process in this work shows better separation performance than most OSN membranes reported in literatures, and has bright prospects for industrial organic solvents treatment.

Catalytic Conversion of Lignin Model Compound and Kraft Lignin over Reduced Ru/C Catalyst

AbstractCatalytic conversion of lignin into valuable liquid products has been a promising approach. Herein, we reported the catalytic conversion of the lignin model compound and Kraft lignin over reduced Ru/C catalyst with different industrial organic solvents using a high‐pressure/ high‐temperature reactor in a nitrogen atmosphere. The results showed reduced Ru/C catalyst is stable for two runs and active for the conversion of the lignin model compound (2‐phenoxy‐1‐phenyl ethanol) with a breaking of the C−O ether bond at high temperature. In the case of Kraft lignin, 2‐butanol and ethanol were potential solvents for the lignin conversion. The Ru/C catalyst enhanced the conversion of lignin, and the highest Kraft lignin conversion (~68 %) was obtained by using ethanol solvent at 220 °C for 1 h reaction. The product distribution with most small phenolic compounds demonstrated the potential of Kraft lignin conversion over the Ru/C catalyst.

2,5-Hexanedione Affects Ovarian Granulosa Cells in Swine by Regulating the CDKN1A Gene: A Transcriptome Analysis.

N-hexane, a common industrial organic solvent, causes multiple organ damage owing to its metabolite, 2,5-hexanedione (2,5-HD). To identify and evaluate the effects of 2,5-HD on sows' reproductive performance, we used porcine ovarian granulosa cells (pGCs) as a vehicle and carried out cell morphology and transcriptome analyses. 2,5-HD has the potential to inhibit the proliferation of pGCs and induce morphological changes and apoptosis depending on the dose. RNA-seq analyses identified 4817 differentially expressed genes (DEGs), with 2394 down-regulated and 2423 up-regulated following 2,5-HD exposure treatment. The DEG, cyclin-dependent kinase inhibitor 1A (CDKN1A), according to the Kyoto Encyclopedia of Genes and Genomes enrichment analysis, was significantly enriched in the p53 signaling pathway. Thus, we evaluated its function in pGC apoptosis in vitro. Then, we knocked down the CDKN1A gene in the pGCs to identify its effects on pGCs. Its knockdown decreased pGC apoptosis, with significantly fewer cells in the G1 phase (p < 0.05) and very significantly more cells in the S phase (p < 0.01). Herein, we revealed novel candidate genes that influence pGCs apoptosis and cell cycle and provided new insights into the role of CDKN1A in pGCs during apoptosis and cell cycle arrest.

Coating polyurethane sponge with Dy-MOF for efficient oil–water separation in complex environments

Leakage of industrial oil and organic solvents seriously harms environment and ecology yet demanding highly efficient and durable materials for oil–water separations. In this work, ultra-light and highly flexible polyurethane (PU) sponges were engineered to 3D oil–water separators by coating the dysprosium metal organic framework (Dy-MOF) onto the surfaces of the PU frames. Through a facile impregnation, the Dy-MOF was attached to the full frames of the sponges. Consequently, liquid contact surfaces were extended from these on top layers to the whole rack. Superhydrophobicity with water contact angles up to 152.08° and lipophilicity enable continuous separations of dichloromethane from water through the resulted Dy-MOF@PU sponges in a continuous mode. The modified sponges own high gravimetric absorption capacities for oil and organic solvents, and high resistances to temperature variations, corrosive solutions, and mechanical abrasions, thanks to the well-connected and stable superhydrophobic/supportive interfaces. An efficient separation was successfully piloted for oily wastewater consisting of water-in-oil emulsions stabilized by surfactants, demonstrating the potential of practical water treatment of Dy-MOF@PU in complex environments. Mechanism leading to superior oil–water separation capability was studied and inferred as the combined effects of the physical and chemical properties arisen from the stable Dy-MOF and flexible but porous matrix.

Exploiting phase inversion for penta-amine impregnation of ultrafiltration support matrix for rapid fabrication of a hyper-cross-linked polyamide membrane for organic solvent nanofiltration

For the sake of recovery of precious organic solvents from industrial organic solvent waste stream or alternatively for recovery of active principle ingredient (API) synthesized in pharmaceutical companies, organic solvent nanofiltration (OSN) membranes have recently been emerged. A thin film composite (TFC) membrane was fabricated by using rapid membrane fabrication technique. The PA(TEPA-TCL)@PSU/PETP membrane was fabricated by penta-amine (TEPA) impregnation of polysulfone (PSU) matrix during phase inversion which in turn was reacted with terephthaloyl chloride (TCL) through interfacial polymerization (IP). The PA(TEPA-TCL)@PSU/PETP membrane was characterized by scanning electron microscopy (SEM), water contact angle (WCA), energy dispersive X-ray (EDX) analysis, ATR-FTIR and elemental mapping. The PA(TEPA-TCL)@PSU/PETP membrane was applied for OSN by using water, methanol, ethanol and isopropanol as solvents. When methanol was used as feed, it showed a permeate flux of 28 L m−2 h−1 (LMH) at 20 bar. An inverse relationship was found between viscosity and flux of the solvents. A feed composed of methanol and dyes (dyes were used as model pollutants) was used to evaluate the OSN performance of the membrane. Apparently, size exclusion mechanism was found to be responsible for rejection of dyes as EBT was rejected up to > 92 % and Congo red (CR; M.W. = 696.6 g mol−1) rejection reached > 96% while it stayed at ≈ 88 % for Methylene blue (MB; M.W. = 319.8 g mol−1). The UV-Visible analysis of feed and permeate was conducted which confirmed the rejection of CR and MB. Hence, the PA(TEPA-TCL)@PSU/PETP membrane was found to be efficient for the purification of organic solvents contaminated with organic dyes.

Design, Development, and Outlook of Superwettability Membranes in Oil/Water Emulsions Separation

AbstractOil leakage and discharge of industrial organic solvents are the main reasons for the oily wastewater. The separation of oil/water emulsions has been a global challenge due to the small particle size of the emulsions and their stabilities. An effective method is needed to resolve these issues. Superwettability membrane method has demonstrated a high separation efficiency, fast separation speed, low energy consumption, good scalability, easy operation, and recyclability. In essence, the special wettability of material is mainly determined by two factors: the chemical compositions of material surface and the surface morphology. Herein, in this review, the development of special wettability separation membranes is discussed including different preparation methods, and material preparation, such as superhydrophobic/super lipophilic, superhydrophilic/underwater superoleophobic, superlipophilic/superhydrophobic under oil, smart membranes with switchable wettability, and special wettability membranes with self‐healing or self‐cleaning property. The representative works of each part are introduced, focusing on preparation methods, innovations and separation performance of membranes. Finally, challenges and future directions in this field are also described.

Fractionation of lignin produced from the Earleaf Acacia tree by sequential industrial organic solvents

Introduction: Understanding the fractions of lignin is important for further conversion of lignin into valuable products. Herein, the “home-made” lignin from Earleaf Acacia tree was extracted by sequential industrial organic solvent and characterized each fraction to reveal its properties for further catalytic applications.&#x0D; Methods: In this work, lignin was prepared from the Earleaf Acacia tree using the soda method. Then, the prepared lignin was fractionated by sequential solvents of ethyl acetate, ethanol, methanol, and acetone. Each lignin fractions were characterized by FT-IR and GPC.&#x0D; Results: The FT-IR results confirmed the soda method can produce lignin from woodchips. The fractionation of lignin separated the lignin mixture into different molecular weight fraction from light – medium into heavy compounds.&#x0D; Conclusion: Lignin was produced from woodchips using the soda method successfully. The fractionation using the sequential organic solvents showed the separation of different molecular weight of lignin, which allow to apply for the further conversion into useful products.

Characteristics of Volatile Organic Compounds in Wood Coatings and Automotive Coatings in China

Presently, there are a few studies on the measurement of industrial organic solvents in China. To determine the content and species of volatile organic compounds (VOCs) in industrial organic solvents and to provide the emission factors of organic solvents, the Chinese wood and automotive coatings, which accounted for the largest proportion of production in the world, were investigated. Coating samples were obtained by sampling from companies and buying from markets, and were measured in accordance with the domestic standard testing methods for coatings. The content and composition spectrum of VOCs in the coatings were determined, and the ozone formation potential (OFP) was then calculated. The results showed that for wood coatings, the average content of the VOCs in solvent-based, water-based, and ultra-violet (UV) coatings were 37.28%, 9.88%, and 18.02%, respectively. For automotive coatings, the average content of the VOCs in water-based original equipment manufacturer (OEM) coating, solvent-based OEM coating, water-based refinishing coating, and solvent-based refinishing coating were 15.06%, 59.90%, 11.79%, and 54.50%, respectively. The content of the VOCs in different types of coatings varied substantially. The main components and OFP contributors were alcohols and ethers for water-based coatings, benzene series and esters for solvent-based coatings, and esters, alcohols, and ethers for UV coatings. The average value of the coating samples could meet the current mandatory national standards, but 12% of the solvent-based wood coating samples and 42% of the solvent-based OEM coating samples did not meet the standards. In addition, except for the benzene series of the water-based wood coatings, the contents of harmful substances in other coating samples were up to the standards.

A review of sustainable lignocellulose biorefining applying (natural) deep eutectic solvents (DESs) for separations, catalysis and enzymatic biotransformation processes

Abstract Conventional biorefinery processes are complex, engineered and energy-intensive, where biomass fractionation, a key functional step for the production of biomass-derived chemical substances, demands industrial organic solvents and harsh, environmentally harmful reaction conditions. There is a timely, clear and unmet economic need for a systematic, robust and affordable conversion method technology to become greener, sustainable and cost-effective. In this perspective, deep eutectic solvents (DESs) have been envisaged as the most advanced novel polar liquids that are entirely made of natural, molecular compounds that are capable of an association via hydrogen bonding interactions. DES has quickly emerged in various application functions thanks to a formulations’ simple preparation. These molecules themselves are biobased, renewable, biodegradable and eco-friendly. The present experimental review is providing the state of the art topical overview of trends regarding the employment of DESs in investigated biorefinery-related techniques. This review covers DESs for lignocellulosic component isolation, applications as (co)catalysts and their functionality range in biocatalysis. Furthermore, a special section of the DESs recyclability is included. For DESs to unlock numerous new (reactive) possibilities in future biorefineries, the critical estimation of its complexity in the reaction, separation, or fractionation medium should be addressed more in future studies.

Novel superhydrophobic surface of cotton fabrics for removing oil or organic solvents from contaminated water

Surface science such as superhydrophobic and superoleophilic surfaces plays a sensitive function in a separating oil/water mixture as a result of increasing industrial oil and organic solvents drainage occurrence. In this work, copper hydroxide nanoneedles layer were synthesized onto Egyptian cotton fabrics (CF) treated with polydopamine, Ag nanoparticles (NPs) and Cu NPs via facile immersion process. Fourier transform infrared, X-ray diffraction and scanning electron microscope (SEM) were used to investigate the functionalized surface of CF with copper hydroxide layer. SEM images confirmed that the modified membranes were rougher compared with pure surface of CF. The contact angle measurement emphasized the hydrophobicity of the modified membranes and it was found that the water contact angle has a value of 168°. The absorption capacity of the modified CF membrane was 10.1 g g − 1 for diesel oil and the separation efficiency of this modified surface was higher than 99%. It was noted that the flux in the case of low viscosity solvent as n-hexane was 72,172.9 Lm− 2 h− 1, while for the viscous oil as diesel was 14,460.3 Lm− 2 h− 1.

Solubility study of lignin in industrial organic solvents and investigation of electrochemical properties of spray-coated solutions

In the present study, six organic solvents that are commonly used in the paint industry (1-butanol, 1-methoxy-2-propanol, 2-propanol, butyl acetate, propylene glycol monomethyl ether acetate, and diethylene glycol monobutyl ether) were tested for their ability to dissolve two distinct lignins: an industrial kraft lignin (KL) and a pilot-scale organosolv lignin (OL). Among the solvents investigated, 1-methoxy-2 propanol (Dowanol™ PM, DPM) and diethylene glycol monobutyl ether (Butyl Carbitol™, BC) demonstrated high degrees of solubility (> 98 wt. % at 25 °C) that were comparable to the commonly used lignin solvent, dimethyl sulfoxide (DMSO). Lignin coatings were prepared by spray-coating the new lignin-solvent solutions on iron-phosphated steel, prior to investigation of their subsequent morphological and electrochemical performance characteristics. It was found that KL/DPM coatings demonstrate suitable short-term (1 h, 5% NaCl) anticorrosive characteristics with an increased charge transfer resistance (Rct) compared to the bare steel (1.5 × 105 Ω. cm2cf. 1.9 × 103 Ω. cm2). However, a prolonged (24 h) immersion resulted in a decrease in Rct values (1.1 × 104 Ω. cm2), which may indicate that the lignin coating alone is unable to provide long-term protection under these aggressive conditions.

Solution‐blow spun PLA/SiO2 nanofiber membranes toward high efficiency oil/water separation

AbstractWith the ever frequent of industrial organic solvent emissions and oil spillages, the development of high efficiency oil/water separation materials has attracted extensive attention. Here, PLA‐based nanofiber membranes modified with metal oxides (SiO2, TiO2, Al2O3, and CeO2) are fabricated through blow spinning the mixed solution of polylactic acid (PLA) and metal oxide nanoparticles (NPs). Results shows that the addition of SiO2 NPs significantly increases the hydrophobicity of the membranes, while maintaining the excellent superoleophilicity. The PLA/SiO2 nanofiber membranes demonstrate a higher separation performance than pure PLA, PLA/TiO2, PLA/Al2O3, and PLA/CeO2 nanofiber membranes with high separation efficiency (~100%) and permeation flux (17,800 L m−2 h−1 for n‐heptane), as well as prominent oil adsorption capacity (19.9 g/g for n‐hexane). The successful fabrication of metal oxides modified PLA nanofiber membranes with high separation and adsorption ability, and excellent durability hold great application potential in the field of oily wastewater treatment.

Novel separator skimmer for oil spill cleanup and oily wastewater treatment: From conceptual system design to the first pilot-scale prototype development

Abstract Frequent oil spill accidents, oily industrial wastewater and organic solvents discharge have caused alarming and serious environmental, health and economic issues. Therefore, the development of an environmentally friendly, cost-effective and efficient oil–water separation (OWS) technology is highly urgent. Although traditional methods have been demonstrated to be effective, they still suffer from numerous drawbacks. Herein, we report the concept, design, assembly, and testing of novel and advanced proof-of-concept pilot-scale OWSS prototype module for OWS. This system is built around a unique and innovative combination of hydrophobic–hydrophilic porous sorbent materials-based OWS bed and a vacuum-assisted oil collection system, which allows continuous and efficient removal of highly pure oily contaminants from water surface. The main goals of the present work are the development of a prototype design for a pilot-scale system and the fabrication of the prototype module. A detailed description of the design development, main system components, assembly and construction steps is reported herein, focusing predominantly on the main design choices adopted to comply with the challenging technical requirements. System specifications have been defined to obtain optimum prototype performance with simultaneous oil sorption and recovery as well as a high oil uptake rate and selectivity, which will provide a sustainable solution for industry with robust instrumentation. Initial economic analysis including the technical and economic feasibility of the prototype manufacturing and implementation has also been discussed. The first prototype is being manufactured in our facilities, and the operating tests during and after assembly showed excellent OWS performance, which demonstrates that the developed prototype has been constructed successfully. We believe that this simplified separation–collection system design allows its straightforward implementation for large-area oil spill cleanup and in industrial wastewater treatment plants.

Application of Zr-Cluster-Based MOFs for the Adsorptive Removal of Aliphatic Aldehydes (C1 to C5) from an Industrial Solvent.

Metal-organic frameworks (MOFs) are recognized as advanced sorbents for the effective removal and recovery of various hazardous pollutants in liquid and gaseous environments. In this research, the potential applicability of two Zr-based MOFs (UiO-66 (U6) and its amine counterpart UiO-66-NH2 (U6N)) was investigated relative to activated carbon (AC, tested as a reference adsorbent) for the purification of industrial organic solvents (e.g., methanol) from six different carbonyl impurities (CCs (C1 to C5): formaldehyde (FA, CH2O), acetaldehyde (AA, CH3CHO), propionaldehyde (PA, C3H6O), butyraldehyde (BA, C4H8O), isovaleraldehyde (IA, C5H10O), and valeraldehyde (VA, C5H10O)). In the sorptive removal of these CCs (both individually and in binary mixtures with FA), U6N showed higher efficacy in capturing all of the target CCs than U6 and AC. The adsorption selectivity of U6N toward single CC compounds was in the order of PA (165.1 mg g-1) > BA (158.9 mg g-1) > IA (154 mg g-1) > AA (136 mg g-1) > VA (131.5 mg g-1) > FA (120 mg g-1). In all binary mixtures, U6N selectively captured FA over the heavier CCs (C2-C5) by 1.5-3.3 times due to the steric hindrance of the C2-C5 aliphatic tails in the pore diffusion mechanism. The preferential adsorption of FA onto U6N can also be accounted for by the contribution of chemical bonding (Schiff base interaction) between the -NH2 groups in U6N and the C═O functionalities (aldehyde molecules) and physisorption, as confirmed by density functional theory (DFT) calculations. Theoretical DFT simulations also revealed that the competition between aldehyde molecules for Brønsted acidic sites (μ3-OH of Zr-clusters) created minor distortions in the U6/U6N frameworks.