This study investigates how membrane transport characteristics affect permeate quality in a 2-pass reverse osmosis (RO) system for ultrapure water (UPW) production. Unlike conventional RO, UPW-RO operates in an ultra-low concentration range. Seven commercial 4-inch RO membrane modules spanning a wide range of water (A) and salt (B) permeability coefficients were evaluated under various second-pass RO feed concentrations (specifically, total dissolved solids (TDS) and total organic carbon (TOC)). Second-pass RO permeate TDS remained almost constant regardless of membrane specifications, whereas the permeate TOC was strongly membrane-dependent. RO permeates from high-permeability membranes showed significantly higher TOC than those from high-selectivity membranes. The experiments also revealed that a high-permeability membrane configuration for both RO passes resulted in excessive TOC leakage, while a high-selectivity membrane configuration mitigated TOC passage at the cost of a high operating pressure requirement. A combination of a high-permeability membrane (the first pass) and a high-selectivity membrane (the second pass) could achieve an acceptable TOC passage with a moderate operating pressure requirement in UPW-RO systems.

Coal slime, typically with particle sizes below 1 mm, is difficult to utilize directly and is frequently associated with energy loss and environmental burden. This study comparatively investigates hot–air drying and transient steam flash drying for the dehydration and upgrading of filter–pressed coal slime. In hot–air drying, elevated temperature and reduced particle size markedly accelerate the drying rate, and the apparent activation energy ranges from 18.39 to 20.96 kJ·mol−1 for different particle sizes. For steam flash drying, the influences of steam pressure, particle size, and holding time on moisture–removal efficiency and physicochemical structure are evaluated. The dehydration performance is enhanced by higher steam pressure and larger particle size, reducing the moisture content of the coal slime from 38% to 20%, with approximately 80% of the total water removed during the transient depressurization stage. Structural analyses reveal partial decomposition of oxygen–containing functional groups and mesopore contraction after flash treatment. Compared with hot–air drying, steam flash drying achieves shorter processing time and lower specific energy consumption. These findings indicate that steam flash drying is governed by a pressure–induced phase transition and enhanced thermodynamic driving force, providing an intensified pathway for the efficient upgrading of high–moisture coal slime.

This study investigated the aroma characteristics of three grades of raw tea leaves and their corresponding jasmine tea products from Guangxi, China. Aromatic profiles of jasmine tea varieties were analysed using two-dimensional gas chromatography-olfactory-mass spectrometry (GC×GC-O-MS), stir bar sorptive extraction (SBSE), and descriptive sensory evaluation. Chemometric methods were applied to compare sensory scores with instrumental data. Volatile compound concentrations and relative odour activity values (r-OAVs) were calculated. The results indicated significant differences in base tea leaf quality: high-grade tea leaf G1 exhibited pure, sweet characteristics, serving as an excellent aroma-absorbing carrier. The scenting process significantly imparted jasmine fragrance to the finished product, although its efficacy was constrained by tea leaf grade. GH1 finished tea exhibited a fresh, vibrant, and rich aroma with a sweet, mellow fragrance and high floral integration. In contrast, GH3, due to its inferior base material quality, yielded a weak aroma after scenting with limited quality improvement. The initial quality of the tea base is the fundamental determinant of the upper limit of the finished jasmine tea’s sensory quality, while the scenting process is the core means of shaping its signature floral aroma. The combination of high-quality tea leaves and precise scenting techniques is essential for developing the fresh, vibrant, and rich flavour profile of premium jasmine tea. This study reveals that the flavour formation of jasmine tea originates from the foundational quality of the tea leaves, providing a theoretical basis for monitoring the aroma quality of jasmine tea produced from different grades of tea leaves.

This study investigates the preparation of a composite material by immobilizing Bacillus subtilis on biochar derived from chicken manure biogas residue for the removal of Cr(VI) from wastewater. The results demonstrated that the composite material (Bacillus subtilis immobilized biochar, BIB) achieved a maximum Cr(VI) removal efficiency of 94.1% in a 100 mg/L Cr(VI) solution within 4 h. The chicken manure-derived biochar not only served as an effective carrier for Bacillus subtilis but also enhanced the Cr(VI) removal efficiency through a synergistic effect with the microorganism. Functional groups such as phosphorus, carboxyl, and hydroxyl groups on the biochar surface played a key role in the sorption of Cr(VI). Bacillus subtilis primarily reduced Cr(VI) to Cr(III) by secreting cellular reductases. The combined action of biochar and Bacillus subtilis increased the Cr(VI) removal rate by 13.71% compared to biochar alone. This study presents a promising approach for Cr(VI) remediation in contaminated water and lays a theoretical foundation for the development of composite materials for Cr(VI) reduction.

Blood is a key biological specimen in forensic analysis for both living and deceased individuals, playing a crucial role in drug testing, blood typing, DNA analysis, and bloodstain pattern examination. In forensics, the decomposition of blood holds particular importance because it is a major biological fluid in the human body and undergoes early chemical changes that attract insects and microorganisms to cadaveric sources. The odor signatures produced during the putrefactive process have recently gained forensic relevance, prompting studies to investigate volatile organic compounds (VOCs) from blood, tissues, animal proxies, and human cadavers to enhance human remains detection and recovery via technological or biological means. This study focuses on cadaveric blood odor profiling, evaluating VOC signatures from human cadavers in an anatomy laboratory using solid-phase micro-extraction (SPME) and gas chromatography–mass spectrometry (GC/MS) upon body receipt. A second phase entailed a degradation analysis using 7 human cadavers and a total of 28 postmortem samples repeatedly sampled over a 4-week period. The findings revealed an increasingly complex odor profile as decomposition progresses, with a notable rise in both the variety and concentration of VOCs. Room temperature samples exhibited a more diverse and rapid VOC release, while refrigerated samples showed slower degradation. These insights contribute to a deeper understanding of decomposition patterns and ultimately refine human remains detection methodologies.

In this study, cerium oxide (CeO2) nanoparticles were successfully synthesized using a simple and cost-effective hydroxide-mediated precipitation method. Comprehensive characterization (XRD, SEM, TEM, FTIR, BET, and UV–Vis) confirmed the formation of uniformly distributed nanoparticles with an average size of ~100 nm, a well-defined crystalline structure, and a high specific surface area of 118.96 m2/g. The CeO2 nanoparticles also exhibited a mesoporous framework with a pore volume of 0.39 cm3/g and an average pore radius of 2.27 nm, demonstrating favorable properties for adsorption applications. Adsorption experiments showed that CeO2 nanoparticles effectively removed Pb2+ from aqueous solutions, achieving a maximum experimental adsorption capacity of 192 mg/g and a removal efficiency of 80% at pH 6 under the tested conditions. Kinetic analysis revealed that the pseudo-second-order model best described the adsorption process, suggesting chemisorption as the dominant mechanism, while equilibrium data were more accurately represented by the Langmuir isotherm model, which predicted a theoretical monolayer capacity (Qm) of 714.2 mg/g. Overall, the findings demonstrate that CeO2 nanoparticles possess a strong affinity toward Pb2+ ions and exhibit promising adsorption performance, indicating their potential applicability for the treatment of lead-contaminated wastewater and their suitability for reuse following regeneration.

Organic pollution poses a serious threat to global water safety, while traditional treatment technologies suffer from low efficiency, high costs, and secondary pollution issues. This study successfully develops a highly efficient separation and photocatalytic degradation composite bismuth oxychloride@graphene oxide/polyimide (BiOCl@GO/PI) membrane by loading GO and BiOCl photocatalysts onto PI supporting membrane. The results show that this composite membrane achieves a rejection of 99.8% for methylene blue (MB) and 87.6% for tetracycline hydrochloride (TC). Under UV irradiation, the membrane exhibits a retention rate decline of only 6.8% after five cycles, with water flux stably maintaining at 605 L m−2 h−1 bar−1. Compared to dark conditions, it demonstrates remarkable flux recovery. This is attributed to the membrane’s excellent photocatalytic degradation activity under UV irradiation. After five degradation cycles, the degradation efficiency is decreased from 97.5 to 88.3%. Studies on radical scavengers indicate that UV irradiation generates free radicals, thereby conferring excellent catalytic activity to the membrane. Its unique synergistic effect between separation and photocatalysis endows it with outstanding self-cleaning performance. This research provides an innovative integrated solution for antibiotic pollution control, demonstrating significant potential for environmental applications.

This study presents an eccentric pipe separator (EPS) designed according to the shallow pool principle and Stokes’ law as a compact alternative to conventional gravitational tank separators for offshore platforms. To investigate the internal oil-water flow characteristics and separation performance of the EPS, both field experiments with crude oil on an offshore platform and computational fluid dynamics (CFD) simulations were conducted, guided by dimensional analysis. Crude oil volume fractions were measured using a Coriolis mass flow meter and the fluorescence method. The CFD analysis employed an Eulerian multiphase model coupled with the renormalization group (RNG) k-ε turbulence model, validated against experimental data. Under the operating conditions examined, the separated water contained less than 50 mg/L of oil, while the separated crude oil achieved a purity of 98%, corresponding to a separation efficiency of 97%. The split ratios between the oil and upper outlets were found to strongly influence the phase distribution, velocity field, and pressure distribution within the EPS. Higher split ratios caused crude oil to accumulate in the upper core region and annulus. Maximum separation efficiency occurred when the combined split ratio of the upper and oil outlets matched the inlet oil volume fraction. Excessively high split ratios led to excessive water entrainment in the separated oil, whereas excessively low ratios resulted in excessive oil entrainment in the separated water. Crude oil density and inlet velocity exhibited an inverse relationship with separation efficiency; as these parameters increased, reduced droplet settling diminished optimal efficiency. In contrast, crude oil viscosity showed a positive correlation with the pressure drop between the inlet and oil outlet. Overall, the EPS demonstrates a viable, space-efficient alternative for oil-water separation in offshore oil production.

Sludge, a by-product of wastewater treatment, contains harmful components that negatively impact the environment. One of the most ecologically viable and cost-effective methods for sludge treatment is anaerobic digestion, which produces biogas and stabilized digestate that can be applied to agricultural land. However, anaerobic digestion has certain limitations that reduce biogas yield. To address these issues, various improvement methods have been developed, including the addition of biochar. Biochar, a carbon-rich biomass, enhances the decomposition of organic matter, reduces ammonia toxicity, and supports the growth of methanogenic archaea. Additionally, biochar improves the quality of the resulting digestate, making it more suitable for agricultural use and plant growth. This sustainable approach to sludge management not only benefits the wastewater sector, but also contributes to the energy and agricultural industries.

The hydrophobic region of semaglutide makes it prone to aggregation in aqueous solution, which leads to serious interception in microfiltration. The influences of pH and low concentrations of salts (NaCl, CH3COONa, Na2SO4 and (NH4)2SO4) on the particle size and zeta potential of semaglutide aggregates were studied in this work. The results showed pH could change the zeta potential on the semaglutide surface, but the impact on semaglutide dispersion was limited. When salts were introduced into aqueous solution, NaCl had a more significant dispersion effect on semaglutide than other salts. Under pH 2.5 or pH 8.0 conditions, the addition of 0.01 mol/L NaCl reduced the average particle size of semaglutide aggregates to below 70 nm. The permeability of semaglutide in microfiltration increased from 60% to 86% under optimized conditions with the PES membrane (0.22 μm), and the adsorption loss also reduced 40%. In addition, this study compared the HPLC detection precision of semaglutide samples prefiltered with different microfiltration filters. Some semaglutide was intercepted by various microfiltration filters, resulting in serious detection errors. When semaglutide was dissolved in the aqueous solution containing 0.01 mol/L NaCl with pH 2.5, the detection error was controlled within 1%.