Pilot-scale Experiments Research Articles

A multiscale investigation on protein addition toward steering agglomeration and yield in spray drying

The positive effect of protein drying aids that reduce the stickiness of sugar-rich products on the spray drying yield is known. However, as agglomeration also depends on stickiness, one can expect an effect of these drying aids on interparticle collisions. Therefore, the effect of protein addition to maltodextrin systems on agglomeration and yield in spray drying was investigated using single droplet drying and pilot-scale spray drying experiments. Single droplet drying was used to compare the sticking regimes of whey and pea proteins at different concentrations. Adding protein increased the chance of creating agglomerates upon forced collisions between a drying droplet and a glass bead. This was reflected in an increased fraction of agglomerated particles in pilot-scale experiments with injection of fines. Pea protein decreased the fraction of non-agglomerated primary particles from 38% to 22% when the protein content in the liquid feed was 50 g/kg dry basis. In pilot-scale spray drying, protein addition improved the yield. Industrially, these results can be used to steer formulations regarding agglomeration and yield.

Low-Temperature NH3-SCR Technology for Industrial Application of Waste Incineration: An Overview of Research Progress

Selective catalytic reduction of nitrogen oxides with NH3 (NH3-SCR) was investigated deeper and deeper with poisoning factors such as H2O, SO2, heavy metals, etc. In order to remove the reheating process before the SCR reactor, the application trend of NH3-SCR technology in the non-power industry is concentrated on the condition of low temperature even ultra-low temperature. The present study summarizes the research process of SO2 and H2O resistance of NH3-SCR catalysts under low temperatures related to the working conditions of municipal solid waste incineration plants. In detail, the effects of a high content of H2O and low concentration of SO2 are reviewed. Other factors such as heavy metals, alkali, or alkaline earth metals in the reaction system, synergistic removal of NOx, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are addressed. Finally, the catalytic performance of assembled monolithic catalysts and pilot-scale experiments are also analyzed for the possibility of industrial application. Hopefully, in view of the questions outlined in this study, valuable insights could be taken into consideration for the development of NH3-SCR in waste incineration.

Optimizing phosphorus precipitation from acidic sewage sludge ash leachate: Use of Mg-rich mining by-products for enhanced nutrient recovery

Phosphorus recovery from Sewage Sludge Ashes (SSA) by wet chemical extraction followed by selective precipitation has gained great attention in recent years, attempting to reduce the anthropic pressure on natural reserves. This study investigates the selective precipitation process at lab- and small pilot-scales by means of two conventional and one innovative precipitating agents, the latter derived from a low-grade magnesium oxide mining by-product (LG-MgO named PC8), assessing the role of the most relevant operating parameters. Lab-scale experiments were performed on leachates obtained from bottom and fly ashes, in which several operating conditions were tested, differing in the type of precipitating agent, target pH and nutrient molar ratio. Based on experimental results, small pilot-scale experiments were conducted with Ca(OH)2 and PC8 at pH 7. Effective phosphorus precipitation was obtained at lab-scale at pH equal to 4 for high Al/P molar ratio, while SSA leachate with low Al/P molar ratio promoted improved phosphorus precipitation (>90%) only at pH higher than 8 with PC8. Small pilot-scale findings confirmed the effectiveness of PC8 in increasing simultaneously the pH and the nutrient content of the solid precipitate. The comprehensive assessment of the samples denoted compliance with the European Regulation (EU 2019/1009), which allows the formulation of different fertilizers with agronomic relevance. This is the first time that experiments from small pilot-scale tests in the field of phosphorus recovery from SSA were investigated using an innovative precipitant providing key information for the process scale-up.

Assessing the sustainability and safety of polyethylene terephthalate (PET) liners for lead service lines (LSL) upgrades

Polyethylene Terephthalate (PET) liners have been proposed by industry as a more cost effective and less disruptive alternative to lead service lines (LSL) replacement. However, concerns have been raised about their aging under real-use conditions and their potential health and environmental impacts. In this study, two approaches were implemented. First, bench and pilot scale experiments were carried out to investigate the aging of a PET liner under conditions that simulate normal usage. Results show early surface oxidation and leaching of potentially hazardous metals (lead, zinc and titanium). No short-term fragmentation of the PET liner into microplastics was observed. Next, a life cycle assessment (LCA) compared the health and environmental impacts of three LSL upgrade alternatives: PET liners and full LSL replacement using either copper or PEX pipes. The installation phase was shown to be the main contributor to impact scores, while the benefits of PET liners are highly dependent on their lifespan. PEX pipes installed by torpedoing lower impacts as compared to PET liners and copper pipes for equal lifespan, while the use of PET liners remains less impactful regarding human health and ecosystem quality when a complete excavation is needed. LCA derived global human health effects due to ingestion of leached metals from PET liners, copper pipes and unreplaced LSL, and showed that PET liners and copper pipes significantly reduce health impacts by 14 and 80 DALY respectively compared to unreplaced LSL. Finally, the Integrated Exposure Uptake Biokinetic (IEUBK) model was used to assess the impact of lead exposure specifically for drinking water ingestion. Estimated Blood Lead Levels (BLL) in children and infants in households with long unreplaced LSL was up to 263.7% and 207.8% greater compared to either replacement with copper pipes or rehabilitation with PET liners, showing the clear benefits of corrective action. Combining experimental results, LCA and biokinetic modeling provides actionable information for utilities to select the best upgrade options, considering environmental, health and practical constraints, whilst identifying remaining data gaps. The relative benefits of PET liners should be carefully evaluated considering their lifespan under real-life conditions, the complete replacement costs after failure, and the growing evidence of micro- and nanoplastics (MNP) risks.

Decentralised by-product valorisation in the dairy value chain: An opportunity for sustainable intensification

Increasing the sustainability of the livestock sector is a vital goal in lowering the environmental burden of food production globally. The dairy sector is of particular interest in this context since it is responsible for a significant share of this burden. In the past, research has focused on approaches to lower the impacts at the farming stage of production, while fewer efforts have been directed at the later stages of the value chain. By-product valorisation is a tool within the wider framework of Circular Economy that allows to increase the efficiency of resource use by increasing the product output at high quality, potentially leading to a sustainable intensification. The present study aims to test this hypothesis. For this purpose, data was collected from a cheese production case study and pilot-scale experiments on whey valorisation, to model several scenarios of by-product valorisation in the dairy value chain. This includes a decentralised valorisation scenario modelled for the purpose of supporting a local Circular Economy and three scenarios representing common valorisation approaches. The impacts of the entire value chain are then assessed based on an attributional LCA considering three different functional units in order to examine the potential for a relative reduction of impacts per unit of product output. The results suggest that while there is no clear favourite among the investigated valorisation scenarios, by-product valorisation in general can lower the relative impacts of the value chain significantly as compared to the base scenario without valorisation. Depending on the valorisation scenario and impact category, impact reductions of up to 14%, 20% and 32% can be achieved for the three functional units, respectively. Hence, by-product valorisation allows for a sustainable intensification. While centralised lower quality valorisation is favourable in terms of product mass and overall process efficiency, decentralised and high-quality valorisation performs better when the economic value of the products is taken into consideration. Thus, the choice for the most suitable approach for a production site will depend on the context of the production and the intentions of the stakeholders.

Oxygen-limited niches enhance activated sludge resilience to shock loads and mitigate antibiotic resistance

Conventional activated sludge (CAS) used in wastewater treatment plants that receive industrial wastewater are frequently challenged by toxic pollutants, which may impede the stable and efficient removal of pollutants. Additionally, these toxic pollutants may also exacerbate the spread of antibiotic resistance genes (ARGs). This study introduces a novel approach by incorporating oxygen-limited niches (i.e., anaerobic/anoxic zones) into CAS systems, demonstrating a significant improvement in resilience against toxic shock loads and ARG mitigation. Pilot-scale experiments revealed that oxygen-limited niches can positively impact the removal of conventional pollutants under toxic shock conditions and enhance the degradation of pharmaceuticals. 16S rRNA gene and metagenomic sequencing highlighted significant differences in microbial communities between the anaerobic/anoxic and aerobic zones. Furthermore, metagenomic analysis revealed that the oxygen-limited niches lead to lower abundance of ARGs, and the proportion of high-risk ARGs in anaerobic/anoxic zone was significantly lower than that in CAS. 14 genera potentially involved in ARG propagation were identified, and their abundance was obviously lower in anaerobic/anoxic zone. Our findings highlight the introduction of oxygen-limited niches as a modification to CAS systems, offering a new and promising strategy for managing toxic shocks, enhancing pollutant degradation, and reducing the health risks associated with ARGs in wastewater treatment processes.

Application of flowsheet modeling for scheduling and debottlenecking analysis to support the development and scale-up of a plasma-derived therapeutic protein purification process

Plasma fractionation stands as a pivotal process for the production of therapeutic and diagnostic proteins, such as albumin and immunoglobulin G. Besides these two primary proteins in human plasma, numerous other proteins can be purified for therapeutic purposes. To support process development, a flowsheet modeling-based approach is utilized to improve production efficiency and productivity while minimizing the resource investments. The flowsheet model is first built to represent the baseline drug substance production process at pilot-scale, with operating parameters extrapolated from lab-scale experiments conducted at CSL Behring. To improve operational efficiency and save costs, throughput analysis is applied to enhance the batch throughput through new process design, scheduling, and bottleneck identification. Through implementing the strategies, the batch throughput could be increased by 47.2 % by introducing one additional operator and one buffer preparation tank into the process. Furthermore, after applying a new strategy involving multiple extractions of the initial material (paste), the batch throughput was doubled, with operating cost of goods reduced by 36.1 %. To assess the performance of the modified design and validate the model results, the pilot-scale experiments with two extractions were performed by CSL Behring and compared with model predictions, resulting in good agreement. This work demonstrates the potential of flowsheet modeling in facilitating process development from lab-scale to pilot-scale, fostering cost-effective and efficient production with limited resource investment.

Preliminary findings on the potential of converting municipal solid waste into refuse-derived fuel as an alternative renewable energy source from the Jakarta waste case study

Abstract The conversion of municipal solid waste (MSW) to refuse-derived fuel (RDF) is a promising technology for addressing waste management issues and obtaining a sustainable source of renewable energy. However, the implementation of RDF technology for MSW management in Indonesia, particularly in urban areas, has not yet been realized. This study aims to evaluate the viability of producing RDF from MSW, specifically the waste generated by Jakarta city, which is representative of other large cities in Indonesia. The research analyzed the MSW, including its physical and chemical properties, such as composition, proximate and ultimate analysis, and energy content. In order to investigate the potential adoption of bio-drying technology for the production of RDF from waste in Jakarta, a pilot scale experiment was conducted using a batch system. The results of the characterization indicate that the sample comprises of more than 50% organic waste, and furthermore, the moisture content in the samples is greater than 60%. The waste typically contains a carbon content of around 50% and a calorific value of approximately 1400 kcal/kg. RDF products produced through bio-drying can achieve a moisture content of 37.88% and a heating value of 2675 kcal/kg. The results further emphasize the potential of the produced RDF as a feasible source of renewable energy.

A novel strategy for recovery of heavy metals and synthesis of Co-rich alloy from the alkali-treated tungsten residue using photovoltaic silicon kerf waste

The treatment of spent cemented carbides using the conventional alkali-acid leaching process results in the generation of hazardous solid waste tungsten leaching residue. This study proposed an alternative process using the alkali-treated tungsten leaching residue (AW-residue) without the acid leaching step, preserving Co in the residue. By using photovoltaic silicon kerf waste (SKW) as a reducing agent, heavy metals (Co, Ni, W, Nb, and Ta) were efficiently extracted from AW-residue and a Co-rich alloy was obtained. The silicothermic reduction process facilitated the recovery of iron group metals (Co, Ni, and Fe) and effectively captured trace refractory metals (W, Ta, and Nb). Phase separation occurred through reduction reaction and viscosity-driven processes between the Co-rich alloy and the slag. Optimal conditions were identified as 20% SKW addition, MgO crucible, and a holding time of 120 min, achieving a total recovery yield of 95.5%, with specific yields for Co (97.7%), Ni (97.0%), W (82.5%), Nb (76.3%), and Ta (70.5%). A 20 kg pilot-scale experiment confirmed the feasibility of the process, yielding 47.0% Co-rich alloy from AW-residue compared to 48.3% in lab-scale experiment, and producing a harmless slag phase. This environmentally friendly approach promotes sustainable recycling of valuable metals in the tungsten industry.

Scaling up gaseous chlorine dioxide (ClO2) treatment in the cold storage of fresh apples

Novel interventions are needed to mitigate microbial risks, like Listeria monocytogenes, before shipping fresh apples to retail markets. Batch gaseous chlorine dioxide (ClO2) in-storage treatments were conducted to assess the inactivation of Listeria innocua, reduction of spoilage microorganisms, and changes in quality. Gaseous ClO2 was generated using equal amounts of dry precursors inside the modified commercial refrigerator with 82 kg and 330 kg apples for pilot and semi-industrial scale experiments, respectively. A cocktail of L. innocua was spot inoculated on the calyx of fresh Fuji apples and treated with an initial ClO2 input of 1.2 g of each precursor/kg of produce at a pilot scale for 30 d and semi-industrial scale for 90 d. Headspace ClO2 concentrations, temperature, and relative humidity were measured during the batch treatments. Reductions of 1.4±0.2 and 1.2 log CFU/mL of Listeria innocua were achieved by pilot-scale and semi-industrial scale trials, respectively. The presence of spoilage microorganisms was not significantly (P>0.05) impacted, and apples displayed no signs of deterioration. This study confirms that ClO2 can significantly inhibit foodborne pathogens, such as Listeria, during prolonged cold storage and reduce the risk of contamination for apple growers.

Integrated circular economic approach of solid waste management and resource recovery: Poultry feather-based keratin extraction and its application in leather processing

The tanning industry faces considerable environmental challenges due to effluent load and hazardous chemical generation during processes like tanning and retanning. Therefore, this research work addresses these issues focusing on the pilot scale extraction and application of poultry feather-based keratin hydrolysate (KH) in leather manufacturing. Through pilot-scale experiments, optimal parameters for NaOH concentration, reaction temperature, and time were used to extract KH effectively. The study explored KH's potential application in chrome tanning and retanning stages as a chrome exhaust aid and keratin filler, respectively. During basification, KH was introduced to enhance chromium uptake by creating additional sites through the provision of crosslinking with collagen (modifying collagen) for better interaction and formation of complex with chromium, which not only streamlined the process by reducing the need for additional chemicals but also improved the thermal stability of the resulting leather product and enhance, the quality of leather. The shrinkage temperature of experimental wet blue leather was recorded to be above 107oC compared to the control wet blue leather which start to shrink at 104oc. Similarly, the percentage chromic oxide content of the experimental wet blue leather was observed to be significantly higher (3.89±0.20%) than that of the control wet blue leather (2.59±0.15). Furthermore, KH replaced commercial protein fillers during retanning, resulting in leathers with enhanced mechanical strength and organoleptic properties. The experimental crust leather treated with keratin solution at pH (5.5) was determined to have better tensile strength (23.4 N/mm2) and tear load (38.7 N/mm) than the control leather with tensile strength and tear load of 19.4 N/mm2 and 29.1 N/mm, respectively. Analytical techniques such as FTIR and XRD confirmed the presence of essential functional groups and protein structures in the KH solution, respectively. Leathers treated with 100 % KH substitution at pH value of 5.5 exhibited superior properties, including increased mechanical strength and thermal stability. Environmental impact assessments revealed a significant reduction in total dissolved solids in the spent liquor when KH replaced conventional fillers. Overall, this research demonstrates the potential of poultry feather-based keratin as an efficient, environmentally friendly filler in leather manufacturing, offering promising results in improving product quality and reducing environmental pollution.

Conversion of microalgae into renewable hydrocarbons through catalytic pyrolysis: A bibliometric analysis

The imperative in transitioning to a low-carbon economy involves capturing and utilizing CO2 emissions from industrial sources. Within this framework, microalgae are widely acknowledged for their capacity to sequester CO2 and biologically convert it into high-energy-content biomass. This biomass subsequently finds applications in the production of biofuels and chemical compounds. Within the biorefinery framework, microalgae biomass undergoes pyrolysis with appropriate catalysts, producing renewable hydrocarbons. This process is significant for developing biofuels intended for aviation and maritime transport. To bolster the technological advancement of microalgae biomass conversion into renewable hydrocarbons, a bibliometric analysis of articles on catalytic pyrolysis of microalgae published in the Scopus search platform was conducted. This analysis identified the first article published in 1990, with publications continuing to the present. Utilizing bibliometric and content analyses, this study emphasized key topics in research and development, evaluating the current state of research on the catalytic pyrolysis of microalgae. A total of 178 articles were identified on the Scopus search platform, with 68 % of these scientific contributions published in the last 5 years. This underscores a recent surge in interest and acknowledgment of emerging technologies centered around decarbonization and biofuel generation directly tied to the catalytic pyrolysis of microalgae. As per bibliometric analysis, the leading three countries in terms of scientific contributions in this field were, sequentially, China, the United States, and Brazil. The journal Bioresource Technology offered the most extensive coverage of catalytic pyrolysis of microalgae. The principal challenges impeding the advancement of catalytic pyrolysis of microalgae from laboratory to industrial scale encompass the substantial energy consumption for thorough microalgae biomass drying, a limited comprehension of kinetic reactions and associated mechanisms, and a need for more results from pilot-scale experiments. Future research directions encompass the development of cost-effective and efficient catalysts for application in pyrolysis.

Growth, Antioxidant Capacity, and Liver Health in Largemouth Bass (Micropterus salmoides) Fed Multi-Strain Yeast-Based Paraprobiotic: A Lab-to-Pilot Scale Evaluation.

A multi-strain yeast-based paraprobiotic (MsYbP) comprising inactive cells and polysaccharides (β-glucan, mannan oligosaccharides, and oligosaccharides) derived from Saccharomyces cerevisiae and Cyberlindnera jadinii could ensure optimal growth and health in farmed fish. This study assessed the impact of an MsYbP on the growth, immune responses, antioxidant capacities, and liver health of largemouth bass (Micropterus salmoides) through lab-scale (65 days) and pilot-scale (15 weeks) experiments. Two groups of fish were monitored: one fed a control diet without the MsYbP and another fed 0.08% and 0.1% MsYbP in the lab-scale and pilot-scale studies, respectively (referred to as YANG). In the lab-scale study, four replicates were conducted, with 20 fish per replicate (average initial body weight = 31.0 ± 0.8 g), while the pilot-scale study involved three replicates with approximately 1500 fish per replicate (average initial body weight = 80.0 ± 2.2 g). The results indicate that the MsYbP-fed fish exhibited a significant increase in growth in both studies (p < 0.05). Additionally, the dietary MsYbP led to a noteworthy reduction in the liver function parameters (p < 0.05), such as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (AKP), and hepatic nuclear density, indicating improved liver health. Furthermore, the dietary MsYbP elevated the antioxidative capacity of the fish by reducing their malondialdehyde levels and increasing their levels and gene expressions related to antioxidative markers, such as total antioxidant ca-pacity (T-AOC), total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), catalase (CAT), nuclear factor erythroid 2-related factor 2 (nrf2) and kelch-1ike ech-associated protein (keap1) in both studies (p < 0.05). In terms of hepatic immune responses, the lab-scale study showed an increase in inflammation-related gene expressions, such as interleukin-1β (il-1β) and transforming growth factor β1 (tgf-β1), while the pilot-scale study significantly suppressed the expressions of genes related to inflammatory responses, such as tumor necrosis factor α (tnfα) and interleukin-10 (il-10) (p < 0.05). In summary, our findings underscore the role of dietary multi-strain yeast-based paraprobiotics in enhancing the growth and liver health of largemouth bass, potentially through increased antioxidative capacity and the modulation of immune responses, emphasizing the significance of employing yeast-based paraprobiotics in commercial conditions.

Improving bio-conditioning dewatering performance of food waste anaerobic digestate at low ambient temperatures by heating treatment

ABSTRACT Food waste anaerobic digestate (FWAD) containing high concentrations of contaminants must be purified or recycled. Bio-conditioning dewatering followed by activated sludge process (BDAS) has emerged as a promising technology for treating FWAD. However, the bio-conditioning dewatering as a pivotal step of BDAS is often negatively affected by low ambient temperatures often occurred in winter. This study investigated the role of heating FWAD in improving the bio-conditioning dewatering performance of FWAD. Batch experiments demonstrated that the bio-conditioning dewatering efficiency increased with temperature rise. Notably, due to the low energy consumption, 50°C was considered to be the most appropriate heating treatment temperature, realizing a drastic reduction of specific resistance to filtration (SRF) of bio-conditioned FWAD from initial 1.24 × 1012 m/kg in the control at a ambient temperature of 10°C to 5.42 × 1011 m/kg and a saving of 25% in bio-conditioning reagents cost. The results of the pilot-scale and large-scale experiments revealed that heating treatment made the bio-conditioning dewatering more stable regardless of the fluctuation of ambient temperature in practical engineering. The decrease in the viscosity of bio-conditioned FWAD and the enhancement in microbial fermentation liquor flocculation capacity through heating treatment played pivotal roles in improving the bio-conditioning dewatering performance of FWAD. This work provides a cost-effective strategy to achieve efficient bio-conditioning dewatering at a relatively low ambient temperature, which was helpful in the engineering application of the novel BDAS process in wastewater treatment.

Enhanced anaerobic digestion of waste-activated sludge by thermal-alkali pretreatment: a pilot-scale study.

The composition of waste-activated sludge (WAS) is complex, containing a large amount of harmful substances, which pose a threat to the environment and human health. The reduction and resource utilization of sludge has become a development demand in sludge treatment and disposal. Based on the technical bottlenecks in the practical application of direct anaerobic digestion technology, this study adopted two different thermal and thermal-alkali hydrolysis technologies to pretreat sludge. A pilot-scale experiment was conducted to investigate the experimental conditions, parameters, and effects of two hydrolysis technologies. This study showed that the optimal hydrolysis temperature was 70 °C, the hydrolysis effect and pH can reach equilibrium with the hydrolysis retention time was 4-8 h, and the optimal alkali concentration range was 0.0125-0.015 kg NaOH/kg dry-sludge. Thermal-alkali combination treatment greatly improved the performance of methane production, the addition of NaOH increased methane yield by 31.2% than that of 70 °C thermal hydrolysis. The average energy consumption is 75 kWh/m3 80% water-content sludge during the experiment. This study provides a better pretreatment strategy for exploring efficient anaerobic digestion treatment technologies suitable for southern characteristic sewage sludge.

Experimental and numerical investigation of iron ore pellet firing using coupled CFD-DEM method

Iron ore pellets are the main feedstock in ironmaking processes. While extensive research has addressed numerical modeling of the iron ore pellet induration process, little effort has been made to describe the intricate thermochemical processes occurring within the reactor starting from the pellet and particularly at the intra-particle scale. In this regard, discrete-continuous methods like CFD-DEM can generate more realistic, irregular particle assemblies, which leads to significantly more accurate predictions of voidage variation, wall effects, temperature distribution, and associated mass transfer phenomena. This study presents a numerical model based on computational fluid dynamics (CFD) coupled with the discrete element method (DEM) to simulate the thermal induration process of iron ore pellets. The presented model solving heat, mass, and momentum conservation equations for both continuous and discrete phases, provides detailed information on the thermochemical aspects of the process. Pilot-scale induration experiment was conducted to validate model predictions in terms of thermal history and final conversion fraction. It was found that inlet charge specifications, such as particle and pellet size, significantly impact the productivity of pelletizing plants, highlighting the potential of the presented model to optimize the process and improve plant productivity.

Enhancing decanter centrifuge process design with data‐driven material parameters in multi‐compartment modeling

AbstractPredicting the separation performance of decanter centrifuges is challenging due to dynamic events within the apparatus. Current methods for designing decanter centrifuges rely on simplified models, often leading to inaccuracies. Consequently, manufacturers must perform time‐intensive pilot scale experiments to derive their own correction factors. Growing computing power sparks interest in alternative modeling strategies. Grey box models (GBM) combine mechanistic white box models (WBM) and data‐driven black box models (BBM), with the optimal structure (parallel or serial) varying by application. For modeling decanter centrifuges, we propose a serial GBM that comprises an artificial neural network that outputs unknown material parameters into a first‐principle multi‐compartment model. Comparing this approach to alternative data‐driven modeling strategies (pure BBM, parallel GBM), we conclude that the serial GBM excels in terms of extrapolation, prediction ability, and transparency while also enabling a better comprehension of the separation process.

Assessing Environmental Impact: Organosolv Extraction of Cellulose Pulp from Wood Waste

In the upcoming years, the paper industry is expected rely on containerboard for packaging, with approximately 80% of it being made from recycled fibers by 2020. Creating a new supply chain for fibers could help mitigate possible shortages. In this context, wood waste emerges as a valuable resource with the potential to serve as a plentiful and cost-effective reservoir for generating new materials, as cellulose fibers. This study presents an assessment of the environmental impact associated with the organosolv extraction of cellulose pulp from wood waste based on a previous in lab study conducted by the authors. The increasing demand for sustainable materials has prompted exploration into alternative methods for cellulose pulp production, with a focus on minimizing environmental footprint. Organosolv extraction, a promising technique, involves the use of organic solvents and acid catalysts to break down lignocellulosic biomass, resulting in high-quality cellulose pulp production. To evaluate the environmental implications of this process, a comprehensive life cycle assessment (LCA) approach was adopted. The LCA framework considers all stages of the organosolv extraction process, from wood waste collection to cellulose pulp manufacture, using a gate-to-gate approach. The functional unit for assessment is set as one ton of cellulose pulp. The dataset utilized for the LCA comprises primary data obtained from laboratory experiments, complemented by secondary data sourced from literature and the Ecoinvent life cycle inventory database. Furthermore, sensitivity analysis was conducted to assess the influence of key parameters on the environmental performance of the organosolv extraction process, with a focus on variations in energy consumption to identify potential areas for optimization and improvement. In summary, this study emphasizes the environmental aspects of utilizing organosolv extraction for cellulose pulp production from wood waste. Further research is warranted to explore energy consumption during the organosolv process for obtaining more precise data and optimizing the process. This could be achieved through pilot-scale experiments or utilizing process simulation software.

Activation flotation of lime-depressed pyrite with carbon dioxide: Performances, mechanism and pilot-scale application

Activation flotation of lime-depressed pyrite by sulfuric acid (H2SO4) is usually accompanied by safety hazards and environmental pollution. Exploring eco-friendly, economical and effective activator to replace H2SO4 holds great significance for the sustainable development of mining industry. In this study, carbon dioxide (CO2) as a potential activator was applied in activation flotation of lime-depressed pyrite. Micro-flotation experiments results showed CO2 significantly improved the floatability of pyrite, and a maximum recovery of 93.94% was achieved under optimal operating conditions. The activation mechanism was investigated by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Results indicated the depression of pyrite by lime was attributed to the formation of iron oxide/hydroxide species and calcium film, and CO2 effectively eliminated these hydrophilic compounds from the surface of pyrite, thus promoted the adsorption of xanthate onto the pyrite surface. Moreover, the anodic oxidation of xanthate on pyrite and the influence of CO2 on this process were investigated by cyclic voltammetry measurements. It was found that xanthate oxidation to form dixanthogen was more likely to occur in the presence of CO2, and this reaction replaced pyrite surface oxidation as the dominant anodic process. Finally, pilot-scale experiments were successfully conducted and the recovery of pyrite reached 93.18%, surpassing the ore dressing index of using H2SO4 as activator in actual production at the same period. Moreover, the concentration of sulfate ions in mineral processing wastewater was significantly reduced, and the annual cost of activator can be saved by 0.52 million RMB. The new process of activation flotation pyrite with CO2 has prospects for large-scale application in terms of activation performance, cost-effectiveness and environmental impact.

Quaternary phosphonium-polyamide membranes for efficient lithium extraction from brine sources

Lithium extraction from brine sources such as salt lakes, seawater, and produced water from oil/gas fields is garnering increasing interests from the academic and industrial sectors due to its cost-effectiveness and reduced environmental impact. A critical technological challenge is the efficient separation of Mg2+ and Li+ ions. Many researchers have reported the preparation of positively charged nanofiltration membranes with quaternary ammonium groups, yet investigations about quaternary phosphonium groups are scarce. In this work, positively charged nanofiltration membranes were prepared utilizing polyethyleneimine as the aqueous phase monomer, trimesoyl chloride as the organic phase monomer, and 3-bromopropyl triphenyl phosphonium bromide as the functionalizing monomer. The TFC-P+ membranes, enriched with a high density of quaternary phosphonium groups and an enhanced Donnan effect, achieve a MgCl2 rejection of 98.9 %, a Mg2+/Li+ selectivity of 81.6, and a water flux of 50 LMH under 0.5 MPa. The membranes possess an enhanced comprehensive separation capability that exceeds that of the majority of nanofiltration membranes documented in scholarly articles. Additionally, the membranes exhibit outstanding anti-fouling and anti-bacterial characteristics, essential for their industrial applications. The preparation method proposed herein is simple and conducive to continuous production processes. In light of the abundant produced water reserves from oil and gas extraction, future work will focus on pilot-scale lithium extraction experiments.