Solid-liquid Separation Research Articles

Effect on the adsorption performance and mechanism of antibiotics tetracyclines by the magnetic biochar used peanut shells as raw materials

Widespread environmental pollution caused by the misuse of tetracyclines (TCs) has become a global issue, necessitating the development of water treatment materials for antibiotic removal. Magnetic biochar (MBC) possesses several advantages, including a wide range of raw material sources and low cost, making it a potential adsorbent that overcomes the limitations of biochar (BC) regarding solid–liquid separation. In this study, peanut shell-derived magnetic biochar loaded with Fe3O4 (Fe3O4/BC) was prepared to study its adsorption performance and environmental factors for TCs. The adsorption mechanism was revealed using adsorption isotherms, adsorption kinetics and thermodynamics. The results showed that the total pore volume was increased, and surface oxygen-containing functional groups were formed of that before BC modification. In a wide pH range, Fe3O4/BC showed high adsorption performance for TCs, with an adsorption rate of over 85%. Chemical adsorption was the main adsorption mechanism, including hydrogen bonding, as well as π-π interactions, electrostatic interactions, intrapore diffusion and hydrophobic interactions. Moreover, reusability and obtaining cost of the material were analyzed, demonstrating its promising application prospects. This study will promote the application of Fe3O4/BC in the removal of antibiotics pollutants from water.

Revealing the influence of additional structure on the flow field characteristics and flocculation performance in thickener feedwell through PIV experiments

Cemented paste backfill (CPB) is a widely used method for resource utilization of tailings. The thickener feedwell is the key equipment for CPB to realize solid-liquid separation. Flocculation is a significant process in treating slurry thickening and dehydration. To reveal the flow field variation in the flocculation process, a range of feedwells with additional structures were devised, containing the guide chute feedwell, guide shelf feedwell, and no-additional structure feedwell. The effects of hydrodynamics on flocculation performance were investigated with particle image velocimetry. The velocity and energy distribution were used to describe the variation of the flow field. The size and fractal dimension of aggregates for the flocculation reaction were studied. Furthermore, the turbidity was compared to evaluate the flocculation performance. The results indicated that additional structure can improve flocculation performance, ultimately achieving efficient solid-liquid separation. The flocculation process in feedwell incorporates the mixing-collision section and settling-growth section along the flow direction, with bounding by additional structure. The ideal high-efficiency feedwell should produce a symmetrical and uniform flow field, providing matched shear strength for two sections. The guide chute feedwell exhibited superior performance, resulting in significantly larger aggregate sizes while also experiencing remarkable compactness compared to the alternative additional structure. The reason is that tailings slurry and flocculant obtain high mixing intensity and residence time in the mixing-collision section, causing the effective collision of micro aggregates, further increasing their size and compactness in the settling-growth section. Meanwhile, gradually decaying energy distribution avoids fragmentation of aggregates. This work is expected to provide theoretical and technical support for the design and optimization of feedwells, finally achieving deep dewatering of tailings slurry, and reducing solid waste pollution in mines.

Thermal decomposition behavior of Mountain Pass rare earth concentrate in air/CO2 atmosphere

The Mountain Pass mine is recognized as one of the world’s primary sources of rare earth minerals. These rare earth minerals mainly consist of bastnaesite and a small amount of monazite phosphate, which cannot be decomposed and recovered through conventional oxidative roasting and hydrochloric acid leaching process. An efficient, clean, and economical process called the "combined method" was proposed for the utilization of the Mountain Pass mine to extract rare earths from Mountain Pass rare earth concentrate (MPREC). The main steps of this process include weak oxidation atmosphere roasting, step leaching of hydrochloric acid, solid-liquid separation, the monazite slag with sulfuric acid roasting water leaching, etc. In this paper, the roasting process of MPREC under a weak oxidation atmosphere was investigated. The study examines the thermal decomposition kinetics, phase transition process, and leaching behavior of MPREC in air/CO2 atmosphere. Results show that, the activation energy (Ea) for MPREC thermal decomposition in air and CO2 atmosphere are 146 and 320 kJ/mol, respectively. At temperature above 500 °C in air or above 700 °C in CO2 atmosphere, REOF are generated from bastnaesite through an in-situ reaction with CaO, which is decomposed from CaCO3, to form CaF2 and rare earth oxide (REO). Thus, F is regulated into solid phase. In an oxidizing atmosphere, the thermal decomposition of bastnaesite is accompanied by the rapid oxidation of Ce(Ⅲ). In contrast, the oxidation of Ce(Ⅲ) in a CO2 atmosphere is significantly inhibited. At 700 °C, the oxidation rate of Ce in air is 74.09%, while in a CO2 atmosphere, it is only 33.83%. The hydrochloric acid leaching experiment shows that, the leaching rate of rare earth after roasting at 600 °C under an air atmosphere reaches to 82.9%, and it reaches 87% after roasting at 800 °C under a CO2 atmosphere. The reduction of Ce oxidation in a weak oxidizing atmosphere significantly improves the leaching rate of Ce.

Design and development of a continuous harvesting system using solid-liquid cyclone separator for harvesting of Dunaliella salina for mass production of biomass: Part-1: Performance in single-stage

Microalgae is a viable alternative to depleting conventional fuel sources, a solution to the industrial requirement of organic consumables, and an option for a green and sustainable economy for biofuels, pigments, and nutrient production. Dunaliella salina is an efficient choice among various species due to its high lipid/carotenoid content and growth in extreme saline conditions. Existing batch-production harvesting methods, such as centrifugation and flocculation, are neither inexpensive nor environmentally benign. This paper presents the experimental studies on three different Rietema-type solid-liquid cyclone separators (RSLCS) for continuous harvesting of microalgae as a concentrated trap for mass biomass production to achieve an economy for biofuels and other desirable by-products if required. Two of these RSLCS were modified and had two inlets (orthogonal RSLCS and parallel RSLCS) when compared with conventional RSLCS. The experiments were performed to calculate the growth of microalgae culture on different days (Day-7, 14, 21, and 28), and concentrations of outflows on day-28 were used as feed for all the RSLCS. The recorded separation efficiency for conventional, orthogonal, and parallel RSLCS are 61.66 %, 67.95 %, and 60.14 % respectively. CFD simulations were also done to validate the results, and CellProfiler was used to measure the size of Dunaliella salina for hydrodynamic analysis. The CFD simulations showed separation efficiency of 60.72 %, 67.04 %, and 59.52 % for conventional, orthogonal, and parallel RSLCS. Thus, the use of orthogonal RSLCS is proposed as a simple, cheap, and eco-friendly solution to the industry-level requirement of continuous harvesting for microalgae in replacement of existing batch-production techniques.

Study on strengthening of sulfide tailings high-efficiency solid-liquid separation using water reducing admixtures

The global focus on refined mineral processing and environmental protection has led to stricter requirements for tailings disposal processes. The complex composition and chemical environment of tailings pose challenges in sedimentation and pipeline transportation. This research developed a new additive that is suitable for disposing of copper-lead-zinc sulfide tailings. This additive not only improves sedimentation efficiency and concentration, but also enhances the flowability of high-concentration slurry. This study investigated the effects of four typical water reducing admixtures on the settling and rheological properties of tailings. However, the combination of lignin/PCE and NPAM had a synergistic effect, further improving settling and rheological performance. The addition of PCE increased settling rate by over 2 times, increased sediment concentration by 6.71%, and significantly reduced slurry viscosity and yield stress. The study also used FBRM to analyze the changes in particle/floc size distribution over time. The results showed that the addition of PCE captured more fine particles during flocculation and formed larger flocs. These findings can be used as a reference for the use and optimization of additives in tailings disposal engineering.

Ultrafast and highly efficient Cd(II) and Pb(II) removal by magnetic adsorbents derived from gypsum and corncob: Performances and mechanisms

The utilization of gypsum and biomass in environmental remediation has become a novel approach to promote waste recycling. Generally, raw waste materials exhibit limited adsorption capacity for heavy metal ions (HMIs) and often result in poor solid–liquid separation. In this study, through co-pyrolysis with corncob waste, titanium gypsum (TiG) was transformed into magnetic adsorbents (GCx, where x denotes the proportion of corncob in the gypsum–corncob mixture) for the removal of Cd(II) and Pb(II). GC10, the optimal adsorbent, which was composed primarily of anhydrite, calcium sulfide, and magnetic Fe3O4, exhibited significantly faster adsorption kinetics (rate constant k1 was 218 times and 9 times of raw TiG for Cd(II) and Pb(II)) and higher adsorption capacity (Qe exceeded 200 mg/g for Cd(II) and 400 mg/g for Pb(II)) than raw TiG and previous adsorbents. Cd(II) removal was more profoundly inhibited in a Cd(II) + Pb(II) binary system, suggesting that GC10 showed better selectivity for Pb(II). Moreover, GC10 could be easily separated from purified water for further recovery, due to its high saturation magnetization value (6.3 emu/g). The superior removal capabilities of GC10 were due to adsorption and surface precipitation of metal sulfides and metal sulfates on the adsorbent surface. Overall, these waste-derived magnetic adsorbents provide a novel and sustainable approach to waste recycling and the deep purification of multiple HMIs.

Selective removal of Fe(Ⅲ) from HNO3 leach liquor of saprolitic laterite ore: Precipitation efficiency, hydrolysis mechanism, and removal strategy

HNO3 leach liquor of saprolitic laterite ore contains Fe3+, Al3+, Sc3+, Ni2+, Co2+, Mg2+, etc. Efficient removal of Fe3+ while reducing the loss of valuable metals is the key to solution purification. In this paper, a detailed study was carried out on the removal of Fe3+ by hydrolysis precipitation. First, thermodynamic calculations were conducted to analyze the precipitation pH changes and possible hydrolysis products at different temperatures. Subsequently, the experimental results show that more than 99 % Fe can be removed via low-temperature hydrolysis at 25–80 ℃ and pH = 3.0–3.5, but over 40 % Al and 30 % Sc also precipitate together, causing valuable metals losses. Differently, under high-temperature conditions (180 ℃, pH = 1.0, 0.5 h), 99.49 % of Fe can be selectively removed as Fe2O3 product, while other valuable metals hardly precipitate. It was found that the low-temperature Fe removal residue exhibits irregular agglomeration and uneven particle size, and contains 9.48 % NO3– and 25.86 % Fe. The high-temperature Fe removal residue presents a nanoscale spherical shape with uniform particle size and only contains 0.087 % NO3–, and the Fe content is up to 69.07 %. Finally, the Fe3+ hydrolysis mechanism was analyzed and an efficient Fe removal process from the HNO3 system including pH adjustment of leach liquor, selective Fe removal at high temperature, flash evaporation to recover free HNO3, and solid–liquid separation to obtain Fe2O3 products was proposed.

Forage type and additive effects on fermentation quality and biorefinery performance of silages

AbstractThe concept of a green biorefinery has recently gained interest and can be defined as a process where green biomass is processed to a variety of products. Most green biorefineries rely on fresh green biomass as the feedstock, but using a stable ensiled biomass could provide benefits. We evaluated the effects of silage additive treatments on silage fermentation quality and performance in a laboratory scale liquid–solid separation to simulate the first step of a green biorefinery. In Experiment 1, red clover and fresh and wilted grass were ensiled without additive or treated with a lactic acid bacteria inoculant or a formic acid based additive. In Experiment 2, grass or red clover were treated with a fibrolytic enzyme, formic acid or a combination of them, and a control without additive was also included. Silage fermentation quality was improved by additive use. Biomass dry matter concentration was negatively related to liquid yield, but effects of additive treatments on the biorefinery performance were minor and inconsistent between different forages. Optimizing agronomic and feedstock conservation management plays an important role for the success and sustainability of the biorefinery process. Good silage management practices with minimal losses during storage should be targeted, but no clear patterns in biorefinery outputs were observed in the current study when different types of additives were used in grass and clover silage production.

Improved Bending Strength and Thermal Conductivity of Diamond/Al Composites with Ti Coating Fabricated by Liquid-Solid Separation Method.

In response to the rapid development of high-performance electronic devices, diamond/Al composites with high thermal conductivity (TC) have been considered as the latest generation of thermal management materials. This study involved the fabrication of diamond/Al composites reinforced with Ti-coated diamond particles using a liquid-solid separation (LSS) method. The interfacial characteristics of composites both without and with Ti coatings were evaluated using SEM, XRD, and EMPA. The results show that the LSS technology can fabricate diamond/Al composites without Al4C3, hence guaranteeing excellent mechanical and thermophysical properties. The higher TC of the diamond/Al composite with a Ti coating was attributed to the favorable metallurgical bonding interface compounds. Due to the non-wettability between diamond and Al, the TC of uncoated diamond particle-reinforced composites was only 149 W/m·K. The TC of Ti-coated composites increased by 85.9% to 277 W/m·K. A simultaneous comparison and analysis were performed on the features of composites reinforced by Ti and Cr coatings. The results suggest that the application of the Ti coating increases the bending strength of the composite, while the Cr coating enhances the TC of the composite. We calculate the theoretical TC of the diamond/Al composite by using the differential effective medium (DEM) and Maxwell prediction model and analyze the effect of Ti coating on the TC of the composite.

Design, construction and solid-liquid separation performance of a human colon inspired soft-elastic reactor (CSER): Breakage, emptying, and solid-liquid separation of the agar gel particles

A novel colon soft-elastic reactor (CSER), inspired by the human ascending colon and cecum, has been developed and investigated using a model product system. This CSER replicates the behavior of the ascending colon in humans, achieving both peristalsis and segmental propulsion. The design of the bionic colon model is based on silicone and adopts a bag-like structure resembling colon anatomy. Peristalsis and segmental propulsion are simulated using a unique mechano-electric setup. Varying the depth of rolling motion resulted in different breakages of agar gel particles. Increasing the squeezing depth of the rollers against the silicone wall from 70 % to 100 % led to an increase in small-sized particles (< 3.5 mm) from 6.5 % to 66.7 % of the total particle mass. Moreover, increasing the frequency of segmental propulsion from 3.3 to 38.6 times/h reduced the half-life (t1/2) of agar gel particles from 137.9 to 0.4 min. The t1/2 was significantly higher for the 3.0 wt% agar gel (207.4 min) compared to the 1.0 wt% agar gel (113.5 min). During CSER squeezing, solid agar gel particles move upward while liquid flows downward along the wall due to gravity. These findings demonstrate the CSER effectively simulates bottom-to-top chyme transport in the ascending colon.

Low-temperature and low-concentration sodium hydroxide pretreatment for enhanced enzyme hydrolysis rate from Quercus variabilis Blume

A surface response design was employed to develop a sodium hydroxide (NaOH) pretreatment method for Quercus variabilis Blume using low NaOH concentration at low temperature. Nevertheless, the persistent issues associated with alkaline pretreatment of lignocellulose, namely high-water consumption and wastewater generation, remain prevalent in this pretreatment process. To address these challenges, this study aimed to conduct enzymatic hydrolysis of NaOH-treated Q. variabilis Blume without the intermediary washing steps. The results revealed that, following pretreatment and solid-liquid separation, NaOH-treated Q. variabilis Blume could be directly subjected to cellulase-mediated hydrolysis with pH adjustment, eliminating the need for washing steps. The maximum enzymatic hydrolysis efficiency reached 95.9% under specific conditions (1.2% NaOH, 8.9 °C, 32.1 h). This approach offers a promising avenue to enhance the enzyme hydrolysis rate of NaOH-treated lignocellulose. Notably, the low-temperature and low-concentration NaOH treatment effectively removed a substantial portion of lignin and hemicelluloses, resulting in a higher crystallinity index of the cellulose-rich residue compared to substrates treated solely with steam explosion. The integration of direct pretreatment and alkaline treatment emerges as an environmentally friendly and economically viable method for producing glucose and high-purity lignin. The obtained lignin can be further transformed into high-value products within the biorefinery framework.

Evaluation of solid-liquid separation of dairy manure with different separator screen sizes on the resource recovery and greenhouse gas emissions reduction

Solid-liquid separation is a critical step for the treatment of dairy manure, and the separator screen size plays an important role in determining the separation. Despite its importance, the impact of screen size on subsequent resource recovery and greenhouse gas (GHG) emissions reduction remains largely undetermined and varied. In this study, the influence of separator screen size for solid-liquid separation on resources recovery (bedding materials, biogas and nutrients) and GHG emissions reduction was evaluated. Taking a dairy farm with a stock of 1000 cows as an example, with the increasing of separator screen size from 0.5 mm to 5 mm, the results show that the annual bedding materials production decreased from 987.0 tons to 597.6 tons (dry basis), the annual biogas production increased from 32.5 × 104 m³ to 50.9 × 104 m³, the annual total nitrogen (TN) recovery increased from 35.8 tons to 44.4 tons, and the annual total phosphorus (TP) recovery increased from 8.2 tons to 10.1 tons. The annual economic benefits from resource recovery ranged from 28.7 × 104 ¥ to 34.8 × 104 ¥. Annual total GHG emissions increased with the increasing separator screen size and reached approximately 0.7 t CO2 equivalent/cow·year. These findings provide guidance for the selection of separator screen size for the solid-liquid separation of dairy manure.

Dimensional analysis for sedimentation behavior of magnetorheological fluids

Magnetorheological fluids (MRFs) are primarily composed of magnetic particles suspended in carrier liquids, exhibiting a remarkable capacity to respond dynamically to external magnetic fields. However, the phenomenon of solid–liquid phase separation, attributable to particle sedimentation, represents a formidable barrier to the real-world application of MRFs in engineering contexts. As a result, it becomes critically imperative to conduct a thorough investigation into the sedimentation behavior of MRFs under static conditions, to significantly enhance their practical utility. In the study, computational analysis through COMSOL was utilized to elucidate the sedimentation dynamics of MRFs. The findings indicated that particle sedimentation harbored the potential to induce localized turbulence within the flow field, thereby significantly impacting the sedimentation dynamics of MRFs. The motion of particles consistently followed a pattern where sedimentation rates decreased as the viscosity of the carrier liquids increased. Moreover, the elucidation of the settling behavior of MRFs was facilitated by the introduction of two dimensionless numbers. These dimensionless numbers were employed to systematically characterize the temporal evolution of the supernatant height throughout the settling process. This investigation further explored the intricate interdependence between these dimensionless parameters via a comprehensive series of settling experiments. The outcomes of this research uncovered a unique pattern in the solid–liquid separation process of MRFs, marked by a phase of gradual initiation, followed by acceleration, and culminating in deceleration. However, as the viscosity of the carrier liquids increased, this pattern became less pronounced, gradually shifting toward a more uniform settling trajectory.

Optimized Solid–Liquid Separation of Phenolics from Lavender Waste and Properties of the Dried Extracts

Lavender distillation produces huge quantities of solid waste yearly. This waste is usually discarded, resulting in serious environmental issues. However, it still contains residual essential oil and other bioactive compounds. This research reports on the development and comparison of optimized solid–liquid separation methods, i.e., microwave- (MAE) and ultrasound-assisted extraction (UAE) of phenolic compounds from lavender distillation waste. The optimal pretreatment conditions, such as waste moisture content and particle size, were also determined. The extracts were spray- or freeze-dried and the resulting powders were characterized for their physicochemical properties. The majority of the original phenolic compounds in lavender were found in the leachate fraction after distillation (61%), whereas 43% was found in the solid waste. Drying of the solid waste before extraction affected the process efficiency. UAE led to a higher phenolic content and greater antioxidant properties compared to MAE. Drying (spray or freeze) the extracts did not significantly affect their phenolic content, whereas the use of maltodextrin as a drying agent improved the drying process yield, especially when using the freeze-drying method. It is concluded that valorization of lavender distillation wastes can be achieved via an integrated process consisting of a green extraction method and a consequent drying process that results in a stable bioactive powder.

Regression Metamodel-Based Digital Twin for an Industrial Dynamic Crossflow Filtration Process.

Dynamic crossflow filtration (DCF) is the state-of-the-art technology for solid-liquid separation from viscous and sensitive feed streams in the food and biopharma industry. Up to now, the potential of industrial processes is often not fully exploited, because fixed recipes are usually applied to run the processes. In order to take the varying properties of biological feed materials into account, we aim to develop a digital twin of an industrial brownfield DCF plant, allowing to optimize setpoint decisions in almost real time. The core of the digital twin is a mechanistic-empirical process model combining fundamental filtration laws with process expert knowledge. The effect of variation in the selected process and model parameters on plant productivity has been assessed using a model-based design-of-experiments approach, and a regression metamodel has been trained with the data. A cyclic program that bidirectionally communicates with the DCF asset serves as frame of the digital twin. It monitors the process dynamics membrane torque and transmembrane pressure and feeds back the optimum permeate flow rate setpoint to the physical asset in almost real-time during process runs. We considered a total of 24 industrial production batches from the filtration of grape juice from the years 2022 and 2023 in the study. After implementation of the digital twin on site, the campaign mean productivity increased by 15% over the course of the year 2023. The presented digital twin framework is a simple example how an industrial established process can be controlled by a hybrid model-based algorithm. With a digital process dynamics model at hand, the presented metamodel optimization approach can be easily transferred to other (bio)chemical processes.

A novel approach for purifying food waste anaerobic digestate through bio-conditioning dewatering followed by activated sludge process: A case study

Although anaerobic digestion is the mainstream technology for treating food waste (FW), the high pollutant concentration in the resultant food waste anaerobic digestate (FWAD) often poses challenges for the subsequent biochemical treatment such as activated sludge process. In this study, taking a typical FW treatment plant as an example, we analyzed the reasons behind the difficulties in treating FWAD and tested a novel process called as bio-conditioning dewatering followed by activated sludge process (BDAS) to purify FWAD. Results showed that high concentrations of suspended solids (SS) (16439 ± 475 mg/L), chemical oxygen demand (COD) (24642 ± 1301 mg/L), and ammonium nitrogen (NH4+-N) (2641 ± 52 mg/L) were main factors affecting the purification efficiency of FWAD by the conventional activated sludge process. By implementing bio-conditioning dewatering for solid-liquid separation, near 100% of SS and total phosphorus (TP), 90% of COD, 38% of total nitrogen (TN), and 37% of NH4+-N in the digestate could be effectively removed or recovered, consequently generating the transparent filtrate with relatively low pollution load and dry sludge cake (<60% of moisture content). Furthermore, after ammonia stripping and biochemical treatment, the effluent met the relevant discharge standards regulated by China, with the concentrations of COD, TN, NH4+-N, and TP ranging from 151 to 405, 10–56, 0.9–31, and 0.4–0.8 mg/L, respectively. This proposed BDAS approach exhibited stable performance and low operating costs, offering a promising solution to purify FWAD in practical engineering and simultaneously realize resource recovery.

Pilot test on acidic fluoride-containing wastewater treatment in the photovoltaic industry through induced crystallization with a focus on calcium fluoride recovery

The utilization of hydrofluoric acid in the photovoltaic (PV) industry results in the generation of substantial volumes of acidic fluoride-containing wastewater, emphasizing the significance of wastewater treatment and the reclamation of fluorine resources. In this study, a pilot test was conducted on acidic fluoride-containing wastewater from a PV cell manufacturer in Yangzhou City, Jiangsu Province, China, employing a combined process system integrating chemical crystallization circulating pellet fluidized bed (CrystPFB) and high-efficiency solid-liquid separation pellet fluidized bed (SepPFB). The pilot test outcomes indicate that utilizing CaF2 as a seed crystal and employing a joint addition of Ca(OH)2 and CaCl2 at a combined dosage of 2,300–3,700 mg/L, under conditions of influent fluoride concentration ranging from 800–3000 mg/L and a pH range of 2.23–3.20, reduces fluoride levels in the effluent to 20–30 mg/L. The combined process system achieves a turbidity in the effluent below 5 NTU, a fluoride recovery efficiency of 45–63 %, and an operational cost ranging from 1.68 to 2.46 RMB/m3. The physical analysis of the reclaimed crystalline calcium fluoride particles reveals a dominance of CaF2 on the particle surface, with a purity exceeding 90 %. This study provides essential data supporting the application of the CrystPFB + SepPFB combined process system for treating acidic fluoride-containing wastewater and recovering calcium fluoride in the PV industry, establishing a groundwork for subsequent projects.

Carbon source fate in lysozyme-assistant anaerobic fermentation process of excess sludge: interphase carbon migration, recovery and extraction

Lysozyme has been regarded as promising approach to enhance anaerobic fermentation of excess sludge. However, little investigation has revealed the specific patterns of interphase carbon source migration and recovery. This study demonstrated that the rising lysozyme dosages greatly improved the kinetics and performances of endogenous carbon source release and biotransformation, which mainly occurred within 48-h treatment. Considerable 146.66 mg C/g VSS particulate carbon sources were solubilized from sludge solid, composing of proteins, humic acids and metabolic intermediates. Meanwhile, almost 57.48 % of the originally released carbon sources were bio-transformed into short-chain fatty acids with accelerated sludge acidification, which were regarded as the recoverable carbon source. Correspondingly, considerable carbon recovery of 103.18 mg C/g VSS was achievable by lysozyme assistance in 96-h anaerobic fermentation. Such lysozyme catalysis strategy improved carbon migration and recovery by 5.38 and 6.21 times, respectively. The fermented sludge was easily dewatered after chemical conditioning, thereby the effective carbon source extraction was implemented by solid-liquid separation. Approximately 65.99–87.02 % of the recoverable carbon sources were remained in fermentative liquid. The high ratios of carbon sources to nutrients (nitrogen and phosphorus) suggested favorable bio-availability and utilizability of the recoverable carbon sources. The overall carbon flow and migration pathways in lysozyme-driven patterns were illustrated to directly clarify the carbon source fate in anaerobic fermentation process and carbon recovery benefits from excess sludge.

High-performance pneumatic solid–liquid triboelectric nanogenerator

In the field of blue energy harvesting, solid-liquid triboelectric nanogenerators (SL-TENG) show significant potential. However, their low output performance in energy applications is limited due to the relatively small contact area and slow separation speed during the friction process. To overcome these limitations, we develop a pneumatic solid-liquid triboelectric nanogenerator (PSL-TENG) with ultrahigh output performance based on pneumatic solid-liquid triboelectrification and electrostatic breakdown. The pneumatic design effectively increases the solid-liquid interface area and the solid-liquid contact and separation rate, which can enhance solid-liquid triboelectrification effect. The synergistic design of the horn and the bent pipe can converge positively charged mist into large droplets, which can enhance electrostatic breakdown effect. This innovative design approach has achieved outstanding output performance, with a peak instantaneous voltage of 6436 V and a peak instantaneous current of 3.05 mA. This exceptional output performance is sufficient to directly power 3000 LED lights or a 55 W commercial lamp. These research achievements provide new insights for SL-TENG in energy harvesting, as significant output can be generated by collecting the inherent charges of liquids themselves.

The effect of crystallographic orientation of α-Al2O3 on the wetting behavior and adhesion characteristics of aluminum droplets

To solve the problem of adhesion of aluminum fluid to the inner wall of the vacuum ladle in the aluminum electrolysis industry, molecular dynamics simulation is performed to research the wetting behavior of Al droplets on the surfaces of the α-Al2O3 substrates C (0001), M ( 11ˉ00 ), and R ( 11ˉ02 ) at 1073 K. Meanwhile, the adhesion characteristics of the Al droplet are evaluated by the potential of the mean force (PMF) for the separation of the Al droplets from different surfaces of the α-Al2O3 substrate. The results show that the wetting behavior of Al droplets on the α-Al2O3 substrate is influenced by the different crystallographic orientations. The diffusion of Al droplets in the x-o-y plane of the substrate exhibits isotropic. The PMF and the interfacial potential energy reveal that the magnitude of the adhesion work in the solid-liquid separation of Al droplets from α-Al2O3 substrates follows the order C (0001) > R ( 11ˉ02 ) > M ( 11ˉ00 ). These findings characterize the wetting properties and adhesion behavior of Al droplets on an atomic scale and provide a theoretical basis for the selection of materials for the inner wall of the vacuum ladle.