Post-treatment Techniques Research Articles

Recent Progress and Advances of Perovskite Crystallization in Carbon-Based Printable Mesoscopic Solar Cells.

Carbon-based printable mesoscopic solar cells (p-MPSCs) offer significant advantages for industrialization due to their simple fabrication process, low cost, and scalability. Recently, the certified power conversion efficiency of p-MPSCs has exceeded 22%, drawing considerable attention from the community. However, the key challenge in improving device performance is achieving uniform and high-quality perovskite crystallization within the mesoporous structure. This review highlights recent advancements in perovskite crystallization for p-MPSCs, with an emphasis on controlling crystallization kinetics and regulating perovskite morphology within confined mesopores. It first introduces the p-MPSCs, offering a solid foundation for understanding their behavior. Additionally, the review summarizes the mechanisms of crystal nucleation and growth, explaining how these processes influence the quality and performance of perovskites. Furthermore, commonly applied strategies for enhancing crystallization quality, such as additive engineering, solvent engineering, evaporation controlling, and post-treatment techniques, are also explored. Finally, the review proposes several potential suggestions aimed at further refining perovskite crystallization, inspiring continued innovation to address current limitations and advance the development of p-MPSCs.

Seawater Treatment Technologies for Hydrogen Production by Electrolysis—A Review

Green hydrogen, produced by water electrolysis using renewable energy sources (RES), is an emerging technology that aligns with sustainable development goals and efforts to address climate change. In addition to energy, electrolyzers require ultrapure water to operate. Although seawater is abundant on the Earth, it must be desalinated and further purified to meet the electrolyzer’s feeding water quality requirements. This paper reviews seawater purification processes for electrolysis. Three mature and commercially available desalination technologies (reverse osmosis, multiple-effect distillation, and multi-stage flash) were examined in terms of working principles, performance parameters, produced water quality, footprint, and capital and operating expenditures. Additionally, pretreatment and post-treatment techniques were explored, and the brine management methods were investigated. The findings of this study can help guide the selection and design of water treatment systems for electrolysis.

Development of high flux photocatalytic agcl-cooh-mwcnt/pes ultrafiltration membranes for enhanced waste water treatment and fouling mitigation

A structurally stable AgCl-COOH MWCNT/PES composite membrane was designed and fabricated by combining phase conversion and post-treatment techniques, which can solve the serious membrane fouling in industrial wastewater treatment. The carboxylation of MWCNTs not only enhanced their dispersion but also facilitated their binding with silver chloride, resulting in a stable composite structure that significantly improved contaminant degradation capabilities. The post-treatment technique increased the membrane’s water purification flux by 150 % (reaching 520 L·m2·h−1·bar−1) while maintaining a high BSA retention rate of 95 %. Additionally, the composite membrane demonstrated excellent photocatalytic antifouling properties, with a flux recovery rate of 91.8 % under UV irradiation, and exhibited more than 99 % inhibition of Escherichia coli. This method provides a scalable solution for enhancing the performance of PES membranes in wastewater treatment applications.

Microwave-Assisted Pyrolysis of Carbon Fiber-Reinforced Polymers and Optimization Using the Box-Behnken Response Surface Methodology Tool.

This article introduces an eco-friendly method for the reclamation of carbon fiber-reinforced polymers (CFRP). The research project involved numerous experiments using microwave-assisted pyrolysis (MAP) to explore a range of factors, such as the inert gas flow, the power level, the On/Off frequency of rotation, and the reaction duration. To design the experiments, the three-level Box-Behnken optimization tool was employed. To determine the individual and combined effects of the input parameters on the thermal decomposition of the resin, the data were analyzed using least-squares variance adjustment. The results demonstrate that the models developed in this study were successful in predicting the direct parameters of influence in the microwave-assisted decomposition of CFRPs. An optimal set of operating conditions was found to be the maximum nitrogen flow (2.9 L/min) and the maximum operating experimental power (914 W). In addition, it was observed that the reactor vessel's On/Off rotation frequency and that increasing the reaction time beyond 6 min had no significant influence on the resin elimination percentage when compared to the two other parameters, i.e., power and carrier gas flow rate. Consequently, the above-mentioned conditions resulted in a maximum resin elimination percentage of 79.6%. Following successful MAP, various post-pyrolysis treatments were employed. These included mechanical abrasion using quartz sand, chemical dissolution, thermal oxidative treatment using a microwave (MW) applicator and thermal oxidative treatment in a conventional furnace. Among these post-treatment techniques, thermal oxidation and chemical dissolution were found to be the most efficient methods, eliminating 100% of the carbon black content on the surface of the recovered carbon fibers. Finally, SEM evaluations and XPS analysis were conducted to compare the surface morphology and elementary constitution of the recovered carbon fibers with virgin carbon fibers.

A porous Janus nanofiber membrane with unidirectional water vapor transport for efficient dust personal protection

The generation of coal dust affects all aspects of coal mining, posing a serious threat to miner’s health. However, developing a novel respirator material with high respiratory efficiency and low resistance poses a significant challenge. Additionally, traditional masks can cause water vapor from exhaled breath to condense into minuscule droplets that adhere to the inside of the mask, reducing comfort. In this study, a porous Janus nanofiber membrane was successfully prepared using sequential electrospinning technology combined with post-treatment techniques. Due to its unique porous structure and double-sided anisotropy, the Janus nanofiber membrane achieves high filtration efficiency and low air resistance simultaneously. Under a high-intensity respiration rate of 85 L/min, the Janus nanofiber membrane maintains a filtration efficiency of 99.98 % and a pressure drop of 134.7 Pa. Moreover, the Janus nanofiber membrane can effectively transport water vapor from exhaled breath to the external environment. The external hydrophobic membrane effectively intercepts water mist from the air. The Janus nanofiber membrane water vapor transmittance can reach 2633.863 cm3/m2·d·Pa. The contact angle of the hydrophobic side of the nanofiber membrane reached 145°, while the contact angle of the hydrophilic side reached 0° after 3 s of water droplet exposure. These features greatly improve user comfort. Taken together, our findings demonstrate the promising potential of the newly developed Janus nanofiber membrane for individual protection.

Sulfonation Treatment of Polyether-Ether-Ketone for Dental Implant Uses

There has been a recent uptake in the use of polyether-ether-ketone (PEEK), which is an organic thermoplastic polymer, in the manufacturing of various medical devices, implants, and equipment. Finding the best time and procedure for PEEK after sulfonation is the goal of this research. A total of 30 PEEK discs were sulfonated in this study by immersing them in concentrated (H2SO4) sulfuric acid for various durations and subsequently treated using various post-treatment techniques. Five experiments were carried out, aimed studying the effect of immersion time (5 s–2 min). The methods used as post-treatment were hydrothermal treatment, immersion in NaOH, and washing with acetone. The sulfonation time was measured, and the post-treatment techniques, surface characterizations, were conducted using scanning electron microscopy (SEM) (Electron Optics Instruments, LLC., West Orange, NJ, USA), atomic force microscopy (AFM) (AFM, Vía Burton, CA, USA), and hydrophilic properties. The results were confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The findings of this study demonstrate that sulfonating PEEK caused a structure with a porous network to form in every sample. As the sulfonation time increased, the porous structure became more noticeable and the concentration increased. As a consequence, the roughness of the surface increased notably, and the modified PEEK surface’s wettability improved noticeably. Hydrothermal treatment was determined to be the most successful way for eliminating the leftover sulfuric acid, and sulfonation for 2 min was determined to be ideal. By understanding the best post-treatment procedures and ideal sulfonation duration, a theoretical foundation for the production of sulfonated PEEK for orthopedic uses may be laid.

Post-Treatment and Hybrid Techniques for Prolonging the Service Life of Fused Deposition Modeling Printed Automotive Parts: A Wear Strength Perspective

<div>This study aims to explore the wear characteristics of fused deposition modeling (FDM) printed automotive parts and techniques to improve wear performance. The surface roughness of the parts printed from this widely used additive manufacturing technology requires more attention to reduce surface roughness further and subsequently the mechanical strength of the printed geometries. The main aspect of this study is to examine the effect of process parameters and annealing on the surface roughness and the wear rate of FDM printed acrylonitrile butadiene styrene (ABS) parts to diminish the issue mentioned above. American Society for Testing and Materials (ASTM) G99 specified test specimens were fabricated for the investigations. The parameters considered in this study were nozzle temperature, infill density, printing velocity, and top/bottom pattern. The hybrid tool, i.e., GA–ANN (genetic algorithm–artificial neural network) has been opted to train, predict, and optimize the surface roughness and sliding wear of the printed parts. Results disclose that the minimum surface roughness obtained with GA–ANN was 1.05482 μm for infill density of 68%, nozzle temperature of 230°C, printing velocity of 80 mm/sec, and for concentric type of top/bottom pattern. In extension of this study, annealing was performed on the specimens printed on the optimized results obtained from the analysis at three different temperatures of 110°C, 150°C, and 190°C and for a fixed period of time of 60 min as a post-treatment process to further study the impact of annealing on the surface roughness and wear rate. The surface roughness of the samples showed a discernible improvement as a result of annealing, which can further make significant inroads in automotive industries.</div>

Nanofiber membranes immobilized with in-situ grown nanoparticles for enhanced wetting resistance in direct contact membrane distillation

Immobilizing nanoparticles (NPs) onto the hydrophobic nanofiber membrane surface is an effective method to enhance its resistance to pore wetting in membrane distillation (MD) due to construction of a hierarchical structure. However, loading NPs onto the fabricated membrane through post-treatment techniques (e.g., electrospray, physical vapor deposition etc.) results in agglomeration of NPs and their weak attachment with membrane surface. To address this issue, we utilize precipitation and crystallization methods to achieve in-situ growth of zinc oxide (ZnO) NPs onto nanofiber surface for intensifying their interaction. Morphological characterization demonstrated that the size and amount of in-situ grown ZnO NPs could be controlled by varying reaction time and concentration of precipitation agent. Furthermore, the resultant nanofiber membrane with higher contact angles (163°) showed stable water flux and effective salt rejection in presence of surfactant and oil. Finally, the kinetics of wetting progression monitored by ultrasonic time-domain reflectometry (UTDR) further confirmed that the early partial wetting induced by surfactants was significantly restrained owing to the hierarchical structure generated by the in-situ grown ZnO NPs. This study suggested the modified nanofiber membrane presented outstanding wetting resistance to low-surface-tension foulants and promise for desalination in MD.

Optimisation of Process Parameters to Maximise the Oil Yield from Pyrolysis of Mixed Waste Plastics

The study sought to optimise process parameters of thermal pyrolysis of mixed waste plastic (MWP) to maximise pyrolytic oil yield. High-density polyethylene (HDPE), polypropylene (PP), and polystyrene (PS) were used as feedstocks for pyrolysis. Response surface methodology (RSM) and Box–Behnken design (BBD) were used to optimise the pyrolysis process. The optimisation was carried out by varying three independent variables, namely, reaction temperature (460–540 °C), residence time (30–150 min), and size of MWP feedstock (5–45 mm), to increase the liquid oil yield. A BBD matrix was used to generate the design of the experiments, and 15 experiments were conducted. The highest liquid oil yield of 75.14 wt% was obtained by optimising the operating parameters, which were a reaction temperature of 535.96 °C, a reaction time of 150 min, and a feedstock particle size of 23.99 mm. A model was developed to determine the relationships among the independent variables, and analysis of variance (ANOVA) was used to investigate their impact on maximising oil yield. ANOVA results showed that the temperature and residence time had the maximum impact on oil yield, followed by feedstock size. Physicochemical analysis of the properties of the plastic pyrolytic oil (PPO) revealed that the crude PPO obtained from the MWP had higher water (0.125 wt%) and sulfur content (5.12 mg/kg) and lower flash point (<20 °C) and cetane index (32), which makes it unsuitable for use as an automobile fuel. However, these issues can be resolved by upgrading the PPO using different posttreatment techniques, such as distillation and hydrotreatment.

Acrylamide in food products: Formation, technological strategies for mitigation, and future outlook

AbstractThis review examines various methods of reducing acrylamide levels in processed foods, focusing on thermal and nonthermal methods. Acrylamide, which is mainly formed by the Maillard reaction, poses a health risk and therefore requires the implementation of successful mitigation strategies. The processes by which acrylamide is formed, particularly at temperatures above 120°C, such as frying, roasting, and cooking (however, the practical temperature in the inner of foods does not exceed 120°C), serve as a basis for understanding intervention methods. The effectiveness of thermal technologies, including optimization of time and temperature as well as pretreatment and posttreatment techniques, will be studied in detail. In addition, vacuum‐based technologies such as baking, predrying, frying, deep‐frying, and impregnation are examined to shed light on their underlying mechanisms. Advanced thermal techniques such as microwaves and irradiation will be investigated to evaluate their effectiveness in reducing acrylamide. Furthermore, nonthermal methods, including pulsed electric fields, ultrasound treatments, and novel combinations such as pulsed electric fields and blanching, are being investigated. Various enzymatic interventions with asparaginase and glucose oxidase as well as yeast treatments and fermentations offer a wide range of intervention possibilities. The use of additives/coatings and plant extracts, such as edible coatings, polyphenols, and specific ingredient formulations, has shown promise for acrylamide reduction. This paper highlights the commercial implications, future prospects, and barriers to implementation of these methods. By examining different approaches, this comprehensive analysis emphasizes the importance of using different strategies to successfully reduce acrylamide levels in processed foods and provides guidance to the food industry to improve product safety and quality.

Optimization of Atomic Layer Deposition Processes for Enhanced Semiconductor Performance

Optimization of Atomic Layer Deposition (ALD) processes is critical for enhancing semiconductor performance, ensuring precise control over material deposition and thickness uniformity. This paper investigates various methodologies and strategies employed in ALD to achieve improved semiconductor device characteristics. Key factors such as precursor chemistry, deposition temperature, cycle time, and post-treatment techniques are explored to optimize ALD processes effectively. The study emphasizes the role of advanced characterization techniques in evaluating film properties and device performance enhancements resulting from optimized ALD processes.

Unraveling nanosprings: morphology control and mechanical characterization.

Nanosprings demonstrate promising mechanical characteristics, positioning them as pivotal components in a diverse array of potential nanoengineering applications. To unlock the full potential of these nanosprings, ongoing research is concentrated on emulating springs at the nanoscale in terms of both morphology and function. This review underscores recent advancements in the field and provides a comprehensive overview of the diverse methods employed for nanospring preparation. Understanding the general mechanism behind nanospring formation lays the groundwork for the informed design of nanosprings. The synthesis section delineates four prominent methods employed for nanospring fabrication: vapor phase synthesis, templating methods, post-treatment techniques, and molecular engineering. Each method is critically analyzed, highlighting its strengths, limitations, and potential for scalability. Mechanical properties of nanosprings are explored in depth, discussing their response to external stimuli and their potential applications in various fields such as sensing, energy storage, and biomedical engineering. The interplay between nanospring morphology and mechanical behavior is elucidated, providing insights into the design principles for tailored functionality. Additionally, we anticipate that the evolution of state-of-the-art characterization tools, such as in situ transmission electron microscopy, 3D electron tomography, and machine learning, will significantly contribute to both the study of nanospring mechanisms and their applications.

Preparation and Characterization of Calcium Carbonate Masterbatch-Alkali Soluble Polyester/Polyester Porous Fiber via Melt Spinning.

Porous fibers have gained significant attention for their lightweight and high porosity properties in applications such as insulation and filtration. However, the challenge remains in the development of cost-effective, high-performance, and industrially viable porous fibers. In this paper, porous fibers were fabricated through the melt spinning of an alkali soluble polyester (COPET)- CaCO3 masterbatch and PET slice. Controlled alkali and acid post-treatment techniques were employed to create porous structures within the fibers. The effects on the morphology, mechanical, thermodynamic, crystallinity, pore size, and thermal stability were investigated. The results indicate that the uniform dispersion of CaCO3 particles within the fiber matrix acts as nucleating agents during the granulation process, improving the thermal resistance and strength of the porous fiber. In addition, the porous fiber prepared by COPET/CaCO3 to PET with an 85/15 ratio and post-treated on 4% NaOH and 3% HCl exhibits a "spongy body" with uniformly small pores, favorable strength (2.71 cN/dtex), and elongation at break (47%).

The fate of antibiotic resistance genes during anaerobic digestion of sewage sludge with ultrasonic pretreatment.

This study investigated the effect of ultrasonic (US) pretreatment at three different contact times (30, 45, and 60 min) with a power of 240 W and frequency of 40 kHz on the fate of antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and enteric pathogens during anaerobic digestion (AD) of sludge. By using real time-qPCR, three MGEs (int1, int2, and tnpA) and seven ARGs (sul1, sul2, tetW, tetA, tetO, ermF, and aac(6')-lb) were quantified that have serious human health impacts and represent the most widely used antibiotics (tetracycline, sulfonamide, macrolide, and aminoglycoside). Results indicated that US pretreatment under different contact times improved the removal of ARGs and MGEs. Compared to 30 and 45 min of US pretreatment, 60 min of US pretreatment resulted in a higher reduction of ARGs with total ARG reduction of 41.70 ± 1.13%. Furthermore, the relative abundance of ARGs and MGEs after US pretreatment was reduced more effectively in anaerobic reactors than in a control AD without US pretreatment. The total ARGs and MGEs removal efficiency of control AD was 44.07 ± 0.72% and 63.69 ± 1.43%, and if US pretreatment at different times were applied, the total ARGs and MGEs removal efficiency of the whole pretreatment AD process improved to 59.71 ± 2.76-68.54 ± 1.58% and 69.82 ± 2.15-76.84 ± 0.22%. The highest removal of total ARGs (68.54 ± 1.58%) and MGEs (76.84 ± 0.22%) was achieved after AD with US pretreatment at 45 min. However, US pretreatment and AD with US pretreatment were not effective in inactivation of enteric pathogens (total coliforms and E. coli), suggesting that posttreatment is needed prior to land application of sludge to reduce the level of enteric pathogens. There was no detection of the studied ARGs and MGEs in the enteric pathogens after US pretreatment in subsequent AD. According to this study, long contact times of US pretreatment can mitigate ARGs and MGEs in AD processes, offering valuable insight into improving environmental safety and sustainable waste management. Additionally, the study highlights the need to investigate posttreatment techniques for reducing enteric pathogens in AD effluent, a crucial consideration for agricultural use and environmental protection.

High-Quality Hybrid Perovskite Thin Films by Post-Treatment Technologies in Photovoltaic Applications.

Incredible progress in photovoltaic devices based on hybrid perovskite materials has been made in the past few decades, and a record-certified power conversion efficiency (PCE) of over 26% has been achieved in single-junction perovskite solar cells (PSCs). In the fabrication of high-efficiency PSCs, the postprocessing procedures toward perovskites are essential for designing high-quality perovskite thin films; developing efficient and reliable post-treatment techniques is very important to promote the progress of PSCs. Here, recent post-treatment technological reforms toward perovskite thin films are summarized, and the principal functions of the post-treatment strategies on the design of high-quality perovskite films have been thoroughly analyzed by dividing into two categories in this review: thermal annealing (TA)-related technique and TA-free technique. The latest research progress of the above two types of post-treatment techniques is summarized and discussed, focusing on the optimization of postprocessing conditions, the regulation of perovskite qualities, and the enhancement of device performance. Finally, an outlook of the prospect trends and future challenges for the fabrication of the perovskite layer and the production of highly efficient PSCs is given.

Review on Laser Shock Peening Effect on Fatigue of Powder Bed Fusion Materials

The ability to manufacture parts with complex geometry by sending a model from CAD directly to the manufacturing machine has attracted much attention in the industry, driving the development of additive manufacturing technology. However, studies have shown that components manufactured using additive manufacturing technology have several problems, namely high tensile residual stresses, cracks, and voids, which are known to have a major impact on material performance (in service). Therefore, various post-treatment methods have been developed to address these drawbacks. Among the post-treatment techniques, laser shock peening (LSP) is currently considered one of the most efficient post-treatment technologies for improving the mechanical properties of materials. In practice, LSP is responsible for eliminating unfavorable tensile residual stresses and generating compressive residual stresses (CRS), which result in higher resistance to crack initiation and propagation, thus increasing component life. However, since CRS depends on many parameters, the optimization of LSP parameters remains a challenge. In this paper, a general overview of AM and LSP technology is first provided. It then describes which parameters have a greater influence during powder bed melting and LSP processing and how they affect the microstructure and mechanical properties of the material. Experimental, numerical, and analytical optimization approaches are also presented, and their results are discussed. Finally, a performance evaluation of the LSP technique in powder bed melting of metallic materials is presented. It is expected that the analysis presented in this review will stimulate further studies on the optimization of parameters via experimental, numerical, and perhaps analytical approaches that have not been well studied so far.

Synergetic Effect of Chemical Coagulation and Electroflotation on Synthetic Palm Oil Mill Effluent Treatment

Palm oil mill effluent (POME) is considered the most environmentally harmful when discharged without proper treatment. In addition to conventional biological treatment methods, physicochemical treatment techniques are considered alternative methods to treat POME as polishing or post-treatment techniques to meet the discharge water quality standards set by authorities. Recently, electroflotation (EF) has gained popularity in wastewater treatment owing to its high efficiency, no harmful by-products, and ease of operation. However, EF has limitations on energy consumption because high current density and long electrolysis time are often used to increase the density of gas bubbles and metallic ions produced in the EF system used in pollutant removal. Polyaluminum chloride (PAC) and cationic polyacrylamide (CPAM) are used as alternative options for the production of coagulants instead of using a sacrificial anode in EF. In this study, we hypothesized that PAC and CPAM could enhance the efficiency and reduce the specific energy consumption of EF by minimizing the electrolysis time used in POME treatment. The effects of electrolysis time, current density, and coagulant dosage on POME treatment were investigated. EF treatment at a current density of 2.5 mA/cm2 has achieved 82% of turbidity and 47% of chemical oxygen demand (COD) removal after 45 min electrolysis time, consuming 0.014 kWh of specific energy for the treatment of one gram of COD. There was no improvement in terms of turbidity removal when the current density was increased from 2.5 to 5 mA/cm2; however, the COD removal efficiency was increased up to 52% at 5 mA/cm2. When EF was performed at 1 A combined with PAC at a dosage of 40 mg/L and CPAM at a dosage of 20 mg/L, it was noticed that turbidity and COD removal increased up to 96% and 54%, respectively, within 15 min electrolysis. Subsequently, the specific energy consumption was reduced to 0.004 kWh (by 71%) per one gram of COD treatment. Results confirmed that the chemical coagulants could increase the POME treatment efficiency and reduce the specific energy consumption of EF. However, this method can be improved aiming at further reduction of COD by mineralizing the dissolved organic compounds to fulfill the POME discharge quality standards.

A Review of Additive Manufacturing Post-Treatment Techniques for Surface Quality Enhancement

Additive manufacturing (AM), also known as 3D printing, produces an object layer by layer with the application of a computer-controlled method. AM creates an object by adding material to a solid block until the finished product is created. AM manufacturing benefits including design flexibility, creativity, rapid prototyping, high productivity, reduced manufacturing cycle, etc. However, AM products have physical quality flaws such as surface roughness, inaccurate dimensioning, porosity, staircase effects, etc. Therefore, there is a need to carry out post-treatment on the AM fabricated components to correct their flaws before they can be used. Seventeen different post-treatment methods (PTM) on AM fabricated components were discussed in this review study. Each of these PTMs, however, has its advantages and disadvantages. The results obtained from the study show that chemical PTM has the ability to improve surface roughness easily, laser polishing can be used to reduce the staircase effects, and thus reduce surface roughness significantly and increase the hardness of AM fabricated component parts. Mechanical PTM helps to join the layers of AM components and improve their toughness, while subtractive machining PTM improves surface quality. Thermal PTMs are used to improve corrosion resistance, reduce surface roughness, eliminate staircase effects, etc. The discussion of various PTMs is clearly highlighted to serve as a guide for AM stakeholders.

Investigation of electropolishing performance on surface residual stress and morphology of electrical discharge machined maraging steel

Electrical Discharge Machining (EDM)-machined maraging steel components are promising in the application field of aerospace and production tools. However, the unavoidable adverse effects of recast/white layer formation, high tensile residual stress, and micro-crack on the machined surface necessitate post-treatment techniques. The current study proposed Electropolishing (EP) as a post-treatment process to eliminate EDM’s adverse effects. The performance of EP on surface residual stress and morphology of ED machined surface was evaluated for an optimum combination of parameters, including applied voltage, polishing time, agitation, and temperature. Residual stress has been analyzed using the “sin2 ψ method” of X-ray Diffraction (XRD). After EDM, the generated surface residual stress was 407.17 MPa which had been relaxed to 35.27 MPa after EP. The surface morphology of maraging steel surfaces after EDM and EP were compared using an Atomic Force Microscope (AFM) and Field Emission Scanning Electron Microscope (FESEM). It is observed that micro-cracks, globules, voids, and thermal pitting marks were entirely eradicated following EP. It can also be seen that the EP has successfully removed the formed recast layer during EDM after 6 mins of polishing time. An average of 7.94 µm layer has been removed from the surface, removing all the surface defects. The optical profilometer analyzed the surface roughness profiles, and a 78% improvement in surface roughness was observed after EP.

Valorization of surface-water RO brines via Assisted-Reverse Electrodialysis for minerals recovery: Performance analysis and scale-up perspectives

Reverse osmosis (RO) processes have been recently identified as mostly capable of quantitative removal of salts and contaminants from saline and surface waters, though posing the problem of a concentrated brine to be disposed of and a produced permeate too low in minerals, thus requiring a sometimes expensive remineralization step. In the present paper, Assisted-Reverse Electrodialysis (A-RED) has been proposed for the remineralization of surface-water RO permeate by recovering minerals from its brine. A purposely developed and validated model has been adopted to carry out a parametric analysis for design and optimization of an industrial-scale plant. The techno-economic analysis underlined that full permeate remineralization can be achieved with minimum specific energy consumption of 0.08 kWh m−3, while a minimum remineralization cost of 2.2 c€ m−3 was found applying a permeate by-pass and feed & bleed scheme to (i) increase the plant remineralization capacity and (ii) maintain a stack inlet conductivity above 100–160 μS cm−1 (starting from a permeate ~10 μS cm−1). Compared to current post-treatment techniques, results appear very promising thanks to the reduction of chemicals and total costs as well as environmental concerns related to brine disposal.