TiO2 nanoparticles are found as pigments in coatings and paints and are, therefore, released into the environment through runoff. To assess their environmental impact, comprehensive fate and ecotoxicity studies necessitate particles closely resembling those released into the environment. In response, we developed a method designed to isolate TiO2 particles from commercial paints. Using six contrasting paints alongside a pure TiO2 pigment, we evaluated two extraction methods in terms of recovery, purification rate, and preservation of both inorganic and organic particle coatings. The paints and extracts were characterized using cryogenic-TEM, ICP-OES, thermogravimetry, and infrared spectroscopy. In contrast to the alkaline-based extraction method, the extraction with acetic acid facilitated the retention of both inorganic and organic coatings and ensured good removal of organic polymers. Recovery rates exceeded 70% for all paints and extraction methods, yet the complete removal of SiO2, when present, was not achieved. CaCO3 removal was effective with both extraction methods. Our developed extraction method enables the isolation of TiO2-particles similar to those aged within paints. However, we recommend using silicate-free paints when SiO2 interference is of concern for the study design. Furthermore, this method could be interesting for pigment recycling, offering a gentler alternative to existing techniques which compromise particle coatings.

In the context of sustainable human development and the depletion of petroleum resources, lignin has received widespread attention as a carbon-rich, low-cost, and renewable resource. Owing to their distinctive physical and chemical properties, carbon materials are extensively applied in the fields of adsorption and separation. The conversion of lignin into diverse multifunctional carbon materials, such as porous carbon, activated carbon, carbon fibers, carbon foams, and carbon aerogels, has emerged as a pivotal strategy for the high-value utilization of lignin. In this paper, representative examples of various lignin-based carbon materials utilized in the field of adsorption and separation over the past decade are reviewed and categorized according to the type of carbon materials, and their preparation methods and adsorption effects are described.

The simultaneous determination of 166 pesticides using dispersive liquid–liquid micro extraction combined with gas chromatography–tandem mass spectrometry and ultra-high performance liquid chromatography–tandem mass spectrometry (DLLME–GC-MS/MS+LC-MS/MS) is presented here. In this work, DLLME was extended to complex residues in the ginseng wine matrix. This study first focused on the selection of an appropriate solvent that enabled the dissolution of analytes from ginseng wine. The matrix-matched calibration curves showed good linearity in the range of 2–100 µg L−1 for all pesticides, with coefficients of determination of 0.977–1. The mean recoveries were in the range of 3–124%, with 133 pesticides in the range of 60–130%, and the relative standard deviations (RSDs) were between 0.4% and 31.4%. The limits of detection (LOD) and limits of quantitation (LOQ) were within the ranges of 0.14–140 and 0.5–470 ng L−1, respectively. Therefore, this analytical method contributes to residue analyses of 133 pesticides for the routine laboratory testing of ginseng wine. Research was also carried out by soaking the pesticide-positive samples in ginseng wine to monitor the migration and degradation of pesticides. The results showed that, the migration rates of thifluzamidewaslower than 60%, cyprodinil was 73.7, while azoxystrobin, pyrimethanil, carbendazim, dimethomorph, difenoconazole, pyraclostrobin, propiconazole, quintozene, pentachloroaniline, tebuconazole and phoximwere between 75% and 95%. Quintozene was more easily degraded into pentachloroaniline in the wine.

The CO2 injection technology for replacing CH4 to enhance coalbed methane (CBM) recovery (CO2-ECBM) offers dual benefits, i.e., reducing CO2 emissions through sequestration and increasing CBM recovery, thereby leading to economic gains. However, there is no clear consensus on how temperature and pressure affect the competitive adsorption characteristics of CO2 and CH4 mixed gases in coal. Therefore, the competitive adsorption behavior of CO2 and CH4 mixed gases at various pressures and temperatures were investigated using the breakthrough curve method. Anthracite was selected for the adsorption experiment conducted under three gas injection pressure levels (0.1 MPa, 0.5 MPa, and 1 MPa) and at three temperature levels (20 °C, 40 °C, and 60 °C). This study showed that, when the temperature remained constant and the pressure ranged from 0.1 to 1 MPa, the adsorption rates of CO2 and CH4 increased as pressure rose. Additionally, the selectivity coefficient for CO2/CH4 decreased with an increase in pressure, suggesting that higher pressures within this range are not conducive to the replacement efficiency of CH4 by CO2. As the temperature increased from 20 to 60 °C under constant pressure conditions, both the selectivity coefficients for CO2/CH4 and the adsorption rates of CO2 and CH4 exhibited a downward trend. These findings imply that, within this temperature range, a reduced temperature improves the ability of CO2 to efficiently displace CH4. Moreover, CO2 exhibits a higher isosteric heat of adsorption compared to CH4.

The rapid expansion of industrial and agricultural activities in recent years has significantly contributed to water pollution leading to a decline in water quality and the need for effective treatment and reuse strategies. Metal contamination in water bodies poses severe environmental and health risks, making the development of cost-effective and sustainable remediation methods essential. Among the various treatment approaches, biosorption using biological adsorbents has emerged as a promising alternative due to its low cost and high efficiency. However, while the adsorption mechanisms of single metals are well understood, the competitive interactions between multiple metal ions during the sorption process remain less explored. In this review, we analyze the competitive biosorption of metals in multi-metallic wastewater systems. Key factors influencing metal removal, such as pH, contact time, biosorbent dosage, and initial metal concentration, are discussed, along with the intrinsic properties of biosorbents and metal ions that affect sorption efficiency. Additionally, we highlight recent studies on agroforestry byproducts as effective biosorbents for metal removal, showcasing their potential for sustainable water treatment. Heavy metals pose significant risks even at low concentrations, necessitating robust regulations and advanced treatment technologies; biomass byproducts, as cost-effective biosorbents, can be optimized through pre-treatment, activation, pH and temperature control, and particle size reduction, while effectively managing competitive multi-metal adsorption remains crucial for industrial effluent treatment.

Multiple cyclones working in series are sufficient for heavy separation tasks at the cost of significant energy consumption. The majority of researchers conducting optimization studies on multiple cyclones have attempted to find the best possible compromise between pressure drop and collection efficiency by optimizing the geometry of the cyclones. In a departure from this approach, we report a novel design. Using the proposed method, exit gas is divided into dirty and clean gas by inserting a secondary vortex finder (SVF) into the primary vortex finder (PVF) of the previous cyclone. The dirty gas flows into the succeeding cyclone, whereas the clean gas passes over the succeeding cyclone and directly flows into the device farther behind. Methodologically, the separation performance was tested experimentally, and computational fluid dynamics (CFD) simulations were employed. The Reynolds Stress Model (RSM) for turbulence and the Discrete Phase Model (DPM) were used to simulate the turbulent two-phase flow within the gas–solid separator, capturing the three-dimensional, transient, and turbulent characteristics of the flow. Our performance test results showed that the new series configuration clearly reduces energy consumption while not hindering overall efficiency. The CFD simulation was used to optimize the SVF’s diameter and length. The results indicated that having an SVF with optimal dimensions significantly enhances the vortex flow in the separation space and thus improves the efficiency of the previous cyclone. In addition, an equation was established that describes the volume of gas flowing into a succeeding cyclone.

In this paper, the separation characteristics of mist remover in a wet flue gas desulfurization system are numerically simulated, and the separation mechanism in the channel of mist remover is analyzed considering the influence of droplets on wall recombination, diffusion, and splash. Considering the influence of re-entrainment, a gas–liquid separation model was established to reflect the coupling effect of air flow, droplets, and liquid film in the process of defogging. A computational model based on the energy loss coefficient κ was established, and the numerical simulation of flue gas flow in a single channel of a baffle demister was carried out using the computational fluid dynamics method. The effects of plate distance, plate angle, droplet diameter, and flue gas velocity on the separation efficiency were simulated and analyzed. Based on the response surface method, the model for separation characteristics and structure optimization design of the demister is established, and the influence level of each factor is analyzed.

We have designed, built, and characterized an inexpensive gas chromatograph with photoionization detection using readily commercially available components. These include a home carbonation CO2 cylinder for the carrier gas, headspace sampling using a low pressure six port valve, a standard 30 m wide-bore capillary column, a consumer convection oven including added insulation with a thermocouple, and a photoionization sensor enclosed in a flow cell. The chromatography retention time reproducibility is good due to temperature control within 0.5 °C. The headspace linearity response using a 0.5 mL injection of benzene was from 10 to 250 ppm, with the limit of detection estimated at 4 ppm. The application of this instrument to the headspace monitoring of four soil samples spiked with a commercial adhesive cleaner containing acetone, ethyl benzene, and xylenes was possible. The interaction of acetone with the two different potting soil samples, likely due to their high organic content, was persistent for at least 30 min, even above an ambient temperature (60 °C). A comparison of linear plots of the signal versus volatilization time over the first 20 min showed substantially larger slopes for the two yard soil samples, indicating the rapid volatilization of acetone from these lower organic content soils, as compared to the two potting soil samples. This GC-PID instrument can be considered portable because it can be easily taken apart, transported, and reassembled. One viable option for the extension of the applications of this instrument is to provide hands-on teaching of GC.

This study investigates the synthesis of SMS-Ti-Mn (SMS-Ti-Mn stands for spent mushroom substrate activated carbon-Ti-Mn) nanocomposites and their application in removing the heavy metal antimony from water. In the process of antimony mining and smelting, the concentration of antimony in the waste residue can still reach as high as 80.5 mg/L. In addition, the soil in the electronic waste dismantling area is severely contaminated with antimony. In short, antimony enters the environment in various ways from mining, smelting, and manufacturing to the final waste process and continuously migrates in different environmental media, increasing the environmental exposure risk of antimony pollution. Single-factor experiments and response surface methodology were employed to determine the optimal conditions, including the adsorption time, pH, and solid–liquid ratio. Material characterization was performed to understand the role of nano-metals, and adsorption kinetics were analyzed using the quasi-first-order kinetic model. The research results revealed that the optimal conditions for antimony removal were an adsorption time of 40 min, a pH of 4, and a solid–liquid ratio of 2:1 (mg/mL). Under these conditions, the nanocomposites showed an adsorption capacity of 10.502 mg/g, which was 5.8 times higher than that of iron coagulants, 11 times higher than that of manganese-modified activated carbon, and 1.7 times higher than that of iron–manganese sludge adsorbents. Characterization revealed enhanced functional groups (carbonyl, Ti=O, Mn=O), contributing to improved adsorption. Kinetic analysis indicated physical adsorption as the dominant mechanism, and the regression model accurately predicted the adsorption capacity. SMS-Ti-Mn nanocomposites offer a promising strategy for treating antimony-contaminated water, with strong potential for practical applications in water treatment. They can decompose naturally after use, reduce secondary pollution, and promote ecological balance. Secondly, agricultural waste treated with heavy metal removal can be used as a fertilizer and soil amendment to improve soil quality and promote sustainable agricultural development.

Cyclone separation is a widely utilized separation technique, which enables the self-rotation behaviors of particles in the internal flow field, in order to realize high-performance separation of mixtures. Oily sludges are solid wastes generated by the shale gas industry, which need to be properly treated for environmental protection. In the present investigation, we demonstrated that tuning the inlet flow pattern of the cyclone from linear flow to vortex flow is an effective approach to boost the rotation speed of oily sludge particles for obtaining significantly improved separation effects. Numerical simulations were carried out to investigate the influences of inlet flow pattern on the rotation behaviors of particles, which manifested in the rotation speed of particles being evidently increased up to 4500 rad/s when the inlet flow was tuned from a unidirectional pattern into vortex pattern. The effective rotation zone’s area was also found to increase significantly, with the area of the effective rotation zone enlarged by up to 400%. Further separation experiments on oily sludge were carried out using a cyclone equipped with a worm shell that generated vortex inlet flow with rotating blades. Separation results confirmed that the oily sludge was successfully purified by the cyclone equipped with a worm shell, which provided an extremely high oil removal percentage of 99.9%, showing a 49.1% enhancement in oil removal capability over the individual cyclone separation. Our investigations demonstrated an effective method for realizing oily sludge treatment and oil resource recovery by conventional cyclone separation.