Traditional Wet Process Research Articles

Advancements in Dry Electrode Technologies: Towards Sustainable and Efficient Battery Manufacturing

AbstractTo address the urgent demand for sustainable battery manufacturing, this review contrasts traditional wet process with emerging dry electrode technologies. Dry process stands out because of its reduced energy and environmental footprint, offering considerable economic benefits and facilitating the production of high‐energy‐density electrodes. We spotlight technological innovations that exemplify the paradigm shift towards eco‐friendliness and cost‐efficiency. This review synthesizes the latest developments in dry electrode production, comparing the techniques with conventional methods, and outlines future research for further optimization toward a higher technology readiness level. We suggest that the evolution of battery manufacturing hinges on the synergy between process innovation and materials science, which is crucial for meeting the dual goals of environmental sustainability and economic practicality.

Characterization of the volatile flavour compounds in Yunnan Arabica coffee prepared by different primary processing methods using HS-SPME/GC-MS and HS-GC-IMS

In this study, coffee samples from seven primary processing methods—traditional dry processing (CG), dry processing I (GA), dry processing II (GB), traditional wet processing (CS), honey processing I (MA), honey processing II (MB), and honey processing III (MC)—underwent comprehensive investigation using HS-SPME/GC-MS and HS-GC-IMS. A total of 81 and 96 VOCs were identified by GC-MS and GC-IMS, respectively. The differences in VOCs among various primary processing samples were observed. The results demonstrated increased volatilization of coffee flavor substances due to anaerobic fermentation. CG, GA, and GB samples exhibited high levels of fruity, floral, and sweet aromas. Conversely, honey processing methods (MA, MB, and MC) enhanced the caramel, roasted aroma, and buttery flavor of coffee samples. PCA and PLS-DA successfully categorized coffee beans based on their aroma properties. These findings indicated that honey processing, combined with drying, significantly influenced coffee bean VOCs, enhancing caramel, roasted aroma, and buttery flavor—crucial for the characteristic volatile metabolites of Yunnan arabica coffee beans.

Probe the properties of SBS/CR composite modified asphalt with CR directional distribution

With the aim of studying the properties of SBS/CR modified asphalt with CR directional distributed in SBS, SBS/CR composites were prepared in advance by method of melt blending in this work, and then the SBS/CR composite modified asphalts were prepared by the traditional wet process. The effect of the content of CR and the compatibility between SBS and CR on modified asphalts were discussed in details. The results show that the increasing blending temperature is conducive to improving the compatibility between SBS and CR, but it led to degradation of polymer modifiers. The hot storage stability of modified asphalt decreases with the growth content of CR, while increases with the increasing blending temperature. The conventional properties, elastoplastic relaxation behavior, temperature-sensitivity and rheological behaviors of modified asphalts were evaluated by the test of cyclic tension, rotational viscosity, dynamic shear rheometer (DSR) and blending beam rheometer (BBR). The results indicate that SBS combined with CR in advance have positive effect on the properties of modified asphalt, which is related to the directional distribution of CR and the improved compatibility between SBS and CR. Furthermore, the pre-blending of CR with SBS enhances the resistance of modified asphalts to thermal-oxidation aging. This work provides further guidance for understanding the modification mechanism of SBS/CR composite modified asphalt and improving the properties of SBS/CR modified asphalt.

One-step natural pyrite-assisted mechanochemical detoxification of Cr(VI) in soda ash Chromite Ore Processing Residue: Effectiveness, mechanisms, and life cycle analysis

Traditional wet and dry Chromite Ore Processing Residue (COPR) detoxification methods consume acid for pH adjustment and produce greenhouse gasses (CO2), yielding potential secondary pollution. It is imperative to develop an environmentally-friendly, efficient, and effective method for COPR treatment. This study reported the one-step natural pyrite-assisted mechanochemical detoxification of Cr(VI) in COPR. Under optimal conditions (i.e., the pyrite/COPR mass ratio of 5% and mechanochemical treatment at 600 rev./min for 2.5 h), Cr(VI) in COPR was efficiently reduced and immobilized, and the leaching concentration of total Cr met the regulatory limit of 5 mg/L. The X-ray absorption near-edge structure (XANES) analysis further verified that the Cr(VI) in treated COPR was 100% reduced to Cr(III). Potential mechanism could be that the enclosed non-exchangeable Cr(VI) in the chromite matrix was exposed to the COPR particle surface under the mechanical action; then, the redox reaction between pyrite and Cr(VI) were induced and enhanced through accumulated crystal defects and generated new surfaces with dangling bonds under mechanical forces. Life cycle assessment (LCA) results highlight that the high energy input is the major contributor eliciting environmental impacts for this current technology. More efficient and cleaner energy supplies should be sought alternatively to overcome the overall sustainability.

High-performance Ni/OMA catalyst achieved by solid-state grinding – A case study of CO methanation

The development of methanation catalysts with a high catalytic activity at low temperatures and a long-term durability at high temperatures is still challenged by the conflicting constraint on the catalyst design. In this work, Ni(NO3)2·6H2O. and ordered mesoporous alumina (OMA) containing different amounts of the P123 template were co-ground to prepare Ni/OMA catalysts. Results indicate that NiO was embedded in the meso-channels of OMA via the solid-state grinding. Moreover, the metal particle size, dispersion and reducibility of the catalyst can be easily regulated by the amount of the residual P123 template in OMA, which can be simply controlled by changing the treatment temperature of the OMA precursor. The optimized 15Ni/OMA-120 with a high dispersion and small size of metallic Ni showed high low-temperature catalytic activity with TOF of 31.5 h−1 and STY of 319.1 molCH4 gcat h−1 at 340 °C, but also demonstrated good anti-sintering and coke-resistance performance with a time-on-stream of 150 h long-term durability at 600 °C, which is comparable with the counterpart 15Ni-OMA prepared by traditional wet-process of one-pot evaporation induced self-assembly.

Emission behavior of crumb rubber modified asphalt in the production process

The volatile and semi-volatile emissions of crumb rubber modified asphalt (CRMA) has a negative effect on atmosphere environment, which might restrict its application in pavement engineering. To solve this problem, it is necessary to understand the emission behavior of CRMA in the production process, which has not been well evaluated yet. The present study aims to investigate the emission behavior of CRMAs during production at 180 °C, 220 °C and 260 °C. Two neat binders and one minus 40 mesh crumb rubber were involved in the preparation of CRMAs. The emission samples were collected by activated charcoal sorbent tube in the laboratory and desorbed by carbon disulfide for further gas chromatography–mass spectrometry (GC-MS) analysis. The results indicate that the emission behavior of volatiles and semi-volatiles can be described with a fast-slow two-stage emission function, consisted of a linear fraction and an exponential fraction. Terminal blend (TB) technology, e.g., 260 °C curing process, offers environmental advantage over traditional wet-process due to the fact that a large amount of emissions in the TB process can be disposed at the refinery. Compared with neat asphalt, crumb rubber modified asphalt (CRMA) has 9 new compounds, including benzothiazole, N-cyclohexylcyclohexanimine, 2,2,4-trimethyl-1,2-dihydroquine, diphenylacetylene, dicyclohexyl disulfide, hexadecanoic acid, octadecanoic acid, N-(1,3-Dimethylbutyl)-N′-phenyl-1,4-phenylenediamin, which are mainly derived from accelerators and additives commonly used in the rubber industry.

An approach to 3D print liquid ceramic slurries

Many industrial processes employed for making ceramics are wet processes that start with a liquid and highly concentrated ceramic slurry that is shaped and consolidated into a ceramic. As 3D printing methods develop, industries are urged to adopt additive manufacturing (AM) to keep up with Industry 4.0. However, current AM methods demand not only new equipment but also new material feedstocks. For example, liquid-based 3D printing relies on the development of printable inks. To address this issue and facilitate the transition to Industry 4.0 for industries producing ceramic parts using traditional wet processes, we propose herein a 3D printing strategy in which inks are liquid ceramic slurries like those used in traditional ceramic industry. A slurry containing BN and SiO2 nanoparticles suspended in water with a total solid loading of 44 vol% and exhibiting high fluidity was selected for our proof-of-concept experiments. Direct ink writing (DIW) was the 3D printing method used to extrude the slurry through a thin nozzle and deposit it onto a porous substrate. As the substrate removes the water from the deposited ink by capillary forces, the printed material consolidates. As a demonstration of this approach, bulk and porous parts were attempted that showed a print resolution of about 0.5 mm and a continuous, defect-free microstructure. These results are promising and could be further explored to print overhanging and larger structures using liquid ceramic slurries of various compositions.

Demonstration of using HF-etchant mixed into CO2 to lift-off thin-film GaAs layers by supercritical fluid technology

The epitaxial lift-off (ELO) process based on selectively etching a thin sacrificial AlAs layer from GaAs substrate was performed using high-concentrated aqueous hydrofluoric (HF) etchant. However, because of using the wet etching method, the traditional ELO process has many drawbacks and limitations. Supercritical fluids (SCFs) naturally have the characteristics of low viscosity, high diffusivity, and zero surface tension. Therefore, the development of a gas-phase-like dry etching method based on mixing HF into CO2 and operating the mixture of HF/CO2 in SCFs condition as etchant is hereby proposed to overcome those bottlenecks existing in traditional wet ELO processes. However, there are no available experimental results for etching AlAs layers by HF in SCFs yet. Therefore, a HF-compatible corrosion-resistant high-pressure system was designed and built up to perform the idea. The capabilities of etching sample in supercritical CO2 (scCO[Formula: see text] had been systemically investigated under various pressures (2000–3000 psi) and temperatures (40–60[Formula: see text]C). Besides, the etching performances separately conducted by using aqueous-HF and anhydrous HF/Pyridine as the source etchant and mixing with scCO2 at a fixed temperature, pressure and etching time were also examined and compared under different equivalent HF concentrations. An evaluation of using acetone as the co-solvent mixed with HF/scCO2 mixture for enhancing the etch rate in different volume ratio of HF/co-solvent was further investigated and discussed. With this system, we demonstrate releasing a size of [Formula: see text] ([Formula: see text]) and 3 [Formula: see text]m-thick free-standing GaAs sheet from a 150 nm AlAs sacrificial layer by the etching sample in HF/scCO2 mixture. The released GaAs sheet was also successfully transferred to a flexible PET substrate by using a PDMS stamp and an adhesive layer of NOA61.

Coffee Processing Wastewater Management: An Overview

Globally, one amongst the major agro-based industry contributing significantly is Coffee. Coffee growing estates use water for pulping and the wastewater generated from coffee pulping activity is generally discharged to the water bodies. The objective of this study was to evaluate the impact of effluents from traditional wet coffee processing plants on the water quality. Coffee fruits are processed by two methods, wet and dry process. The wet processing produces a drink of higher quality and has the advantage of reducing the drying space area and time required. However, this preparation step generates high volume of coffee wastewater as it involves utilizing large volumes of water with concurrent generation of wastewater. Throughout wet processing, coffee fruits generate enormous quantities of high strength wastewater. The so generated wastewater is characterized by high concentrations of organic matter, low pH, nutrients, suspended matter associated with odor and dark color with high chemical oxygen demand and biochemical oxygen demand requiring systematic treatment before disposal. The inadequate disposal of the coffee wastewater into environment directly without proper management and handling will pose aa pollution risk to receiving water body. Efforts have made by various researchers to evolve an alternative method for the treatment of coffee pulping waste and the same is discussed in this paper.

Recent advances in the application of plasma in textile finishing (A Review)

The textile industry is seeking innovative manufacturing technology to increase the quality of the fabric, and society needs modern environmental finishing techniques, such as using plasma Treatment as atmospheric-pressure dielectric barrier discharge (APDBD) corona discharge at atmospheric pressure (CDAP) which are gaining popularity in the textile industry due to their many advantages over traditional wet processing methods the textiles industry is gaining in popularity. The initiation of plasma by air or conventional industrial gases, such as hydrogen H2, N2 and oxygen O2 at ambient pressures, may be accomplished. Plasm introduces usable surface groups to provide properties such as antibacterial, UV, flame retardant and antistatic that are used in various fabrics such as cotton, linen, polyester, and surface fabrics after plasma therapy.

Investigation and improvement of the desulfurization performance of molten carbonates under the influence of typical pyrolysis gases

Co-pyrolysis with oxygen-lean waste tires could improve the quality of pyrolytic oil from the bio-wastes while H2S/COS generated during co-pyrolysis process has a negative impact on the utilization of oil/syngas as well as the flue gas pollution control. Compared to traditional wet desulfurization process, high-temperature desulfurization via molten carbonates could reduce heat loss and favor the recycling of captured sulfur. Notably, small-molecule pyrolytic gases might change the species of sulfur-containing gases and promote the re-emission of absorbed sulfur from the molten salts. To fully understand the effects of pyrolysis gases (H2/CO/H2O/CO2) on molten salts desulfurization efficiency as well as mutual conversion mechanism of H2S and COS, equilibrium compositions calculations and adsorption experiments were carried out in the present study. The results showed that H2/CO had few effects on molten salts desulfurization performance and mutual conversion of H2S/COS. In contrast, CO2 and H2O had obvious adverse effects on desulfurization efficiency through the transferring of free S2− into emitted sulfur-containing gases. More specifically, only a small amount of CO2 reacted with S2− to produce COS while more S2− was converted to H2S and released from the reactor outlet when H2O was introduced. Fortunately, the impact of H2O or CO2 on molten salts desulfurization could be weakened with the addition of CaCO3 by transferring the molten free S2− into precipitated CaS. Besides, multi-stage desulfurization units connected in series and parallel were proposed and estimated, which was confirmed to show good performance to maintain the high desulfurization efficiency from the complicated pyrolytic gases.

The impact of different adsorbents on flavour characteristics of a lentil protein isolate

In this study, the effect of different adsorbents on the reduction of off-flavours within a lentil protein isolate (LPI) was examined by isolating volatile compounds using headspace solid-phase microextraction (HS-SPME), and analysing with gas chromatography–mass spectrometry (GC–MS). LPIs were treated with Amberlite-XAD16N, Amberlite-XAD7HP, Amberlite-XAD4, Sepabeads-SP207 and Diaion-HP20 adsorbents, and then total peak areas of each of the flavour compounds were compared with controls. XAD16N, SP207, and HP20 were able to reduce the levels of aldehydes by 32%, 32%, and 41%, respectively. The aldehyde group of compounds (78% being hexanal) represented the major volatile compound within the LPI. All adsorbents significantly reduced 3,5-octadien-2-one by 61–92%. XAD16N and HP20 were found to be the most effective adsorbents in removing alcohols with decreases of 84% and 80%, respectively. Findings from this study could be integrated into the traditional wet extraction process to produce blander plant protein ingredients.

Understanding Self-assembly, Colloidal Behavior and Rheological Properties of Graphene Derivatives for High-performance Supercapacitor Fabrication

Graphene derivatives, such as graphene oxide (GO) and reduced graphene oxide (RGO), have been widely used as promising two-dimensional nanoscale building blocks due to their fascinating properties, cost-effective production, and good processability. Understanding the intrinsic self-assembling, colloidal, and rheological features of graphene derivatives is of critical importance to establish the formation-structure-property relationship of graphene-based materials. This article reviews recent progresses in our studies of these interesting properties of graphene derivatives for developing high performance supercapacitors. The content is organized to include characteristics of the dispersions of graphene derivatives, self-assembly of nanosheets from liquid medium, colloidal behavior, rheological properties of the dispersions, processing methods based on the properties, and performance of the fabricated supercapacitors. GO and RGO nanosheets are proved to form different types of assembled structures with unique morphologies, such as ultrathin layer-by-layer films, porous aggregates, and nanoscrolls. The unique rheological properties of GO dispersions and hydrogels, feasible for both the traditional wet-processing and newly-developed technology like three-dimensional printing, are highlighted for their potential in structural manipulation and scalable fabrication of graphene-based devices. The research devoted to up-grading the performance of supercapacitors is presented in some details, which could be applicable for fabricating other graphene-based energy storage devices. Some challenges and perspectives in our point of view are given in the last part of this feature article.

Electrode manufacturing for lithium-ion batteries—Analysis of current and next generation processing

• Slurry viscosity must be viewed in the context of shear rate and temperature. • Slurry rheology alone cannot predict electrochemical performance. • Optimal coating drying rate is sensitive to the underlying drying mechanisms. • Next generation electrode manufacturing needs to minimize or eliminate solvent. • Tailored electrode architectures will unlock the lithium-ion battery’s potential. As modern energy storage needs become more demanding, the manufacturing of lithium-ion batteries (LIBs) represents a sizable area of growth of the technology. Specifically, wet processing of electrodes has matured such that it is a commonly employed industrial technique. Despite its widespread acceptance, wet processing of electrodes faces a number of problems, including expensive and dangerous solvent recovery, cut-off waste, coating inconsistencies, and microstructural defects due to the solvent drying process. This review considers each of these issues and discusses which electrode slurry properties should be considered when optimizing wet slurry fabrication. Simultaneously, methods to replace traditional wet processing of electrodes are being extensively researched. Some of these novel electrode manufacturing techniques prioritize solvent minimization, while others emphasize boosting energy and power density by thickening the electrode and, subsequently, creating an organized pore structure to permit faster ion diffusion. This review contemplates the advantages and disadvantages of each of these approaches and provides a comprehensive outlook on the future of electrode manufacturing.

Development of maize ogi powder fortified with polyphenolic rich extract from fluted pumpkin leaves

This study evaluated the effects of fortification of a popular maize porridge (ogi) with the extract of fluted pumpkin leaves. This was with a view to increasing the functionality of the food. Ogi cake was produced via a traditional wet milling process of steeped maize grains. The fluted pumpkin liquid extract was obtained by squeezing the fluted pumpkin leaves in warm water (50°C) in the ratio 1:2 (w/v) for 10 min. The mixture was sieved with double-layered muslin cloth to obtain the liquid extract. The extract was added to ogi cake in the following proportions; 10:100, 25:100, 50:100, 75:100 and 100:100 mL g(-1) of extract to cake to make ogi-extract suspensions. The suspensions were dried at 55°C and milled to obtain ogi powder. The proximate composition, functional properties, some mineral elements, vitamin C content, total phenolic contents (TPC), total flavonoid contents (TFC), anti-radical activity (DPPH), viscosity and sensory evaluation were examined. The addition of fluted pumpkin leaf extract resulted in 83.33 to 1367%, 75 to 325% and 5.43 to 90.05% increase in protein, ash and vitamin C content, respectively. An increase of 64.29 to 803.57%, 12.08 to 71.07% and 32.39 to 110.35% were respectively recorded for TFC, TPC and DPPH activity. Calcium, potassium, sodium, iron and phosphorus increased by 55.23 to 760.58%, 24.69 to 398.49%, 196.43 to 2801.79%, 33.33 to 1150% and 100.38 to 3139%, respectively. Viscosities of the green porridge ranged between 50.72 to 80.84 mPa s. The results for sensory evaluation showed that addition of extract up to 75 mL were accepted by the consumers. The addition of fluted pumpkin leaf extract resulted in the improvement of the nutritional profile without alteration to the aesthetic values of the food apart from colour which would not be a detriment with time and awareness.

Novel air classification process to sustainable production of manufactured sands for aggregate industry

Abstract This work addresses the performance of an own design equipment to classify and clean manufactured sands in a novel sustainable air classification process. The proposed methodology does not use water as the main advantage against the actual wet washing process used in most stone quarries. A real quarry producing 10.4 tons/h of manufactured sands was evaluated and compared with the proposed technology in terms of material balances, types and physical characteristics of products obtained, energy consumptions expressed as CO2 equivalent and local environmental impact. The novel air classification process, tested on a pilot scaled plant, proves to be more efficient than the traditional wet washing process. The main advantage is the production of three aggregates with different particles sizes and without moisture content, against a single wet product obtained by the conventional method.

Recycling of Nd–Fe–B Sintered Magnets Sludge via the Reduction–Diffusion Route To Produce Sintered Magnets with Strong Energy Density

Recently, recycling of severely contaminated Nd–Fe–B sintered magnets sludge had drawn considerable attention due to the concern of environmental burden and high cost of traditional wet process rec...

Assessment of the effluent quality of wet coffee processing wastewater and its influence on downstream water quality

The objective of this study was to evaluate the impact of effluents from traditional wet coffee processing plants on the downstream water quality in Ethiopia. Composite water samples were collected from 11 rivers/streams associated with wet coffee processing plants at the peak hours of coffee processing, and water quality parameters were measured for the wastewater discharged as well as for the river water upstream and downstream of the discharge point. Acidic pH values were recorded for all plant effluents. The organic content of the effluents varied from one plant to another but was considerably high overall, with maximum values of 7200mg/L and 871mg/L for COD and BOD5, respectively. This high level of organic content in the effluents depleted the oxygen content to the level of 0.25mg/L. The organic load and the presence of nutrients invoke a large risk of eutrophication. We found that variations in coffee bean soaking time, pulp fermentation, and the absence of appropriate treatment facilities were the major factors affecting the water pollutant parameters. In general, the measured values of effluent parameters significantly deviated from both the Ethiopian-EPA and US-EPA guidelines. Thus, water bodies and ecosystems located downstream of the traditional wet coffee processing plants are at an alarming risk of ecological disruption, and there may also be severe health consequences for the nearby residents. These findings raise the need for further research into the design and implementation of coffee waste valorization and treatment in view of sustainable coffee production.

Novel processing approach to polymer‐derived ceramic matrix composites

AbstractThe rheological properties of commercially available polycarbosilane, SMP‐10, were analyzed as a function of temperature, to guide development of thermal treatment processes for the improved yield and functionality of polymer ceramic precursors. The curing onset temperature for SMP‐10 was determined to be as low as 100°C for a heating rate of 1°C/min enabling a heat treatment process at 90°C, where low molecular weight oligomers volatilize from the liquid precursor prior to curing. By driving off the low molecular weight oligomers before fabrication of a composite, the mass yield of SMP‐10, from a room temperature liquid state was increased from 77% to 83%. The development of B‐staging processes, or a semicure of SMP‐10, were also demonstrated. B‐staging processes were then applied to polymer infiltration and pyrolysis processing and compared with traditional wet layup CMC processing. It was determined that B‐staging processes did not adversely affect ceramic matrix composite fabrication. B‐staged processing methods were determined to result in less waste, allow ply‐by‐ply control of matrix compositions, and enable time independent processing when compared to traditional wet layup processing methods.

Self-templating thermolysis synthesis of Cu2–xS@M (M = C, TiO2, MoS2) hollow spheres and their application in rechargeable lithium batteries

Owing to their unique structural stability and impressive long-term cycling performance, coated hollow structures are highly attractive for energy storage systems, especially batteries. Many efforts have been devoted and various strategies have been proposed to prepare such materials. In the present work, we propose a self-templating thermolysis strategy, different from traditional wet processing methods, to fabricate cuprous sulfide hollow spheres coated with different shells, by exploiting the thermal decomposition properties of the core (CuS) and the protection provided by the shell. To demonstrate the generality of this synthetic approach, three different coating materials (carbon, TiO2, MoS2) have been chosen to prepare Cu2–xS@C, Cu2–xS@TiO2 and Cu2–xS@MoS2 hollow spheres. All synthesized composite materials were then assembled as electrodes and tested in lithium batteries, showing excellent cycling stability. In particular, the electrochemical properties of Cu2–xS@C were thoroughly investigated. The results of this work provide an alternative route to prepare coated metal sulfide hollow spheres for energy storage applications.