Adsorption Behavior of Diclofenac on Polystyrene and Poly(butylene adipate-co-terephthalate) Microplastics: Influencing Factors and Adsorption Mechanism.

To unveil the intricacies surrounding the interaction between microplastics (MPs) and pollutants, diligent investigation is warranted to mitigate the environmental perils they pose. This exposition delves into the sorption behavior and mechanism of diclofenac sodium (DCF), a contaminant, upon two distinct materials: polystyrene (PS) and poly(butylene adipate-co-terephthalate) (PBAT). Experimental adsorption endeavors solidify the observation that the adsorption capacity of DCF onto the designated MPs amounts to Q(PBAT) = 9.26 mg g-1 and Q(PS) = 9.03 mg g-1, respectively. An exploration of the factors governing these discrepant adsorption phenomena elucidates the influence of MPs and DCF properties, environmental factors, as well as surfactants. Fitting procedures underscore the suitability of the pseudo-second-order kinetic and Freundlich models in capturing the intricacies of the DCF adsorption process onto MPs, corroborating the notion that the mentioned process is characterized by non-homogeneous chemisorption. Moreover, this inquiry unveils that the primary adsorption mechanisms of DCF upon MPs encompass electrostatic interaction, hydrogen bonding, and halo hydrogen bonding. An additional investigation concerns the impact of commonly encountered surfactants in aqueous environments on the adsorption of DCF onto MPs. The presence of surfactants elicits modifications in the surface charge properties of MPs, consequently influencing their adsorption efficacy vis-à-vis DCF.

Desorption of sulfamethoxazole from polyamide 6 microplastics: Environmental factors, simulated gastrointestinal fluids, and desorption mechanisms.

Microplastics (MPs) can enrich pollutants after being released into the environment, and the contaminants-loaded MPs are usually ingested by organisms, resulting in a potential dual biotoxic effect. In this paper, the adsorption behavior of Sulfamethoxazole (SMX) on Polyamide 6 (PA6) MPs was systematically investigated and simulated by the kinetic and isotherm models. The effect of environmental conditions (pH, salinity) on the adsorption process was studied, and the desorption behavior of SMX-loaded PA6 MPs was focused on simulating the seawater, ultrapure water, gastric and intestinal fluids. We found that lower pH and solubilization of SMX by gastrointestinal components (bovine serum albumin (BSA), sodium taurocholate (NaT), and pepsin) can reduce the electrostatic interaction between the surface charge of PA6 MPs and SMX. The result will lead to an increase in the desorption capacity of SMX-loaded PA6 MPs in gastrointestinal fluids and therefore will provide a reasonable mechanism for the desorption of SMX-loaded PA6 MPs in the gastrointestinal fluids. This study will provide a theoretical reference for studying the desorption behavior of SMX-loaded PA6 MPs under gastrointestinal conditions.

Comparing the adsorption of methyl orange and malachite green on similar yet distinct polyamide microplastics: Uncovering hydrogen bond interactions.

Microplastics (MPs) and dye pollutants are widespread in aquatic environments. Here, the adsorption characteristics of anionic dye methyl orange (MO) and cationic dye malachite green (MG) on polyamide 6 (PA6) and polyamide 66 (PA66) MPs were investigated, including kinetics, isotherm equilibrium and thermodynamics. The co-adsorption of MO and MG under different pH was also evaluated. The results reveal that the adsorption process of MO and MG is suitably expounded by a pseudo-second-order kinetic model. The process can be characterized by two stages: internal diffusion and external diffusion. The isothermal adsorption equilibrium of MO and MG can be effectively described using the Langmuir model, signifying monolayer adsorption. Furthermore, the thermodynamic results indicated that the adsorption was spontaneous with exothermic and endothermic properties, respectively. The results of binary systems reveal that MO dominates the adsorption at low pH (2-5), while MG dominates at high pH (8-10). Strong competitive adsorption was observed between MO and MG in neutral conditions (pH 6-8). The desorption experiments confirm that PA6 and PA66 could serve as potential carriers of MO and MG. The interaction between dyes and polyamide MPs is primarily mediated through hydrogen bonds and electrostatic attraction. The results reveal that PA6 formed more hydrogen bonds with the dyes, resulting in higher adsorption capacity than that of PA66. This difference can be attributed to the disparities in the synthesis process and polymerization method. Our study uncovered the adsorption mechanism of dye pollutants on PA6 and PA66, and provided a more comprehensive theoretical basis for the risk assessment concerning different types of polyamide MPs in aquatic environments.

Efficient photon upconversion enabled by strong coupling between silicon quantum dots and anthracene.

Hybrid structures formed between organic molecules and inorganic quantum dots can accomplish unique photophysical transformations by taking advantage of their disparate properties. The electronic coupling between these materials is typically weak, leading photoexcited charge carriers to spatially localize to the dot or to a molecule at its surface. However, we show that by converting a chemical linker that covalently binds anthracene molecules to silicon quantum dots from a carbon-carbon single bond to a double bond, we access a strong coupling regime where excited carriers spatially delocalize across both anthracene and silicon. By pushing the system to delocalize, we design a photon upconversion system with a higher efficiency (17.2%) and lower threshold intensity (0.5 W cm-2) than that of a corresponding weakly coupled system. Our results show that strong coupling between molecules and nanostructures achieved through targeted linking chemistry provides a complementary route for tailoring properties in materials for light-driven applications.

Preparation of Reusable Porous Carbon Nanofibers from Oxidized Coal Liquefaction Residue for Efficient Adsorption in Water Treatment.

Porous carbon nanofibers are commonly used for adsorption processes owing to their high specific surface area and rich pore structure. However, the poor mechanical properties of polyacrylonitrile (PAN)-based porous carbon nanofibers have limited their applications. Herein, we introduced solid waste-derived oxidized coal liquefaction residue (OCLR) into PAN-based nanofibers to obtain activated reinforced porous carbon nanofibers (ARCNF) with enhanced mechanical properties and regeneration for efficient adsorption of organic dyes in wastewater. This study examined the effects of contact time, concentration, temperature, pH, and salinity on the adsorption capacity. The adsorption processes of the dyes in ARCNF are appropriately described by the pseudo-second-order kinetic model. The maximum adsorption capacity for malachite green (MG) on ARCNF is 2712.84 mg g-1 according to the fitted parameters of the Langmuir model. Adsorption thermodynamics indicated that the adsorptions of the five dyes are spontaneous and endothermic processes. In addition, ARCNF have good regenerative performance, and the adsorption capacity of MG is still higher than 76% after 5 adsorption-desorption cycles. Our prepared ARCNF can efficiently adsorb organic dyes in wastewater, reducing the pollution to the environment and providing a new idea for solid waste recycling and water treatment.

Gas-phase grafting for the multifunctional surface modification of silicon quantum dots.

Photon upconversion in systems incorporating inorganic quantum dots (QDs) is of great interest for applications in solar energy conversion, bioimaging, and photodynamic therapy. Achieving high up-conversion efficiency requires not only high-quality inorganic nanoparticles, but also precise control of their surface functional groups. Gas-phase surface functionalization provides a new pathway towards controlling the surface of small inorganic nanoparticles. In this contribution, we utilize a one-step low-temperature plasma technique for the synthesis and in-flight partial functionalization of silicon QDs with alkyl chains. The partially functionalized surface is then modified further with 9-vinylanthracene via thermal hydrosilylation resulting in the grafting of 9-ethylanthracene (9EA) groups. We have found that the minimum alkyl ligand density necessary for quantum dot solubility also gives the maximum upconversion quantum yield, reaching 17% for silicon QDs with Si-dodecyl chains and an average of 3 9EA molecules per particle.

Adsorption of Diclofenac Sodium by Aged Degradable and Non-Degradable Microplastics: Environmental Effects, Adsorption Mechanisms.

Microplastics (MPs) are novel pollutants, which can carry toxic contaminants and are released in biota and accumulate. The adsorption behavior of MPs and aged MPs has attracted extensive attention. In this paper, the aging process of polystyrene (PS) and poly (butyleneadipate-co-terephthalate) (PBAT) plastics under ultraviolet (UV) irradiation at a high temperature and their adsorption properties for the contaminant diclofenac sodium (DCF) before and after aging was investigated. There are many factors affecting the adsorption capacity of MPs. In this experiment, three aspects of MPs, organic pollutants, and environmental factors are explored. The Freundlich model as well as the pseudosecondary kinetic model is more applicable to the process of DCF adsorption by MPs. The main effects of adsorption of organic pollutants by MPs are electrostatic interactions, hydrogen-halogen bonds, and hydrophobic interactions. The adsorption capacity of the UV-aged MPs on DCF is significantly enhanced, and the order of adsorption capacity is Q(A-PBAT) (27.65 mg/g) > Q (A-PS) (23.91 mg/g) > Q (PBAT) (9.30 mg/g) > Q (PS) (9.21 mg/g). The results show that more active sites are generated on the surface of MPs after aging, which can enhance their adsorption capacity for organic pollutants. This adsorption mechanism will increase their role as contaminant carriers in the aquatic food chain.

Bidirectional triplet exciton transfer between silicon nanocrystals and perylene.

Hybrid materials comprised of inorganic quantum dots functionalized with small-molecule organic chromophores have emerged as promising materials for reshaping light's energy content. Quantum dots in these structures can serve as light harvesting antennas that absorb photons and pass their energy to molecules bound to their surface in the form of spin-triplet excitons. Energy passed in this manner can fuel upconversion schemes that use triplet fusion to convert infrared light into visible emission. Likewise, triplet excitons passed in the opposite direction, from molecules to quantum dots, can enable solar cells that use singlet fission to circumvent the Shockley-Queisser limit. Silicon QDs represent a key target for these hybrid materials due to silicon's biocompatibility and preeminence within the solar energy market. However, while triplet transfer from silicon QDs to molecules has been observed, no reports to date have shown evidence of energy moving in the reverse direction. Here, we address this gap by creating silicon QDs functionalized with perylene chromophores that exhibit bidirectional triplet exciton transfer. Using transient absorption, we find triplet transfer from silicon to perylene takes place over 4.2 µs while energy transfer in the reverse direction occurs two orders of magnitude faster, on a 22 ns timescale. To demonstrate this system's utility, we use it to create a photon upconversion system that generates blue emission at 475 nm using photons with wavelengths as long as 730 nm. Our work shows formation of covalent linkages between silicon and organic molecules can provide sufficient electronic coupling to allow efficient bidirectional triplet exchange, enabling new technologies for photon conversion.

[Relationship between blood lactic level, lactic clearance, duration of lacticemia and prognosis of critically ill patients in intensive care unit].

OBJECTIVE: To study and quantify the relationship between dynamic lactic acid monitoring indexes and prognosis of critically ill patients in intensive care unit (ICU). METHODS: One hundred and one critically ill patients with elevated blood lactic acid level were included in this study and divided into death group (n=50) and survival group (n=51). Differences in their lactic acid indexes (including: lactic acid level, duration of lacticemia, lactic clearance), acute physiology and chronic health evaluation II (APACHEII) score, and other clinical indicators which reflected organ/system status were compared, and prognostic significant lacticemia indexes were formulated by multi-variable logistic analysis. Subsequently, patients were grouped by significant lactic indexes separately and compared with incidence of shock/multiple organ dysfunction syndrome (MODS), APACHE II score and mortality. RESULTS: Differences in lactic acid level, peak lactic acid level, 12-hour and 24-hour lactic acid clearance between death group and survival group showed statistically significant difference (P<0.05 or P<0.01). Peak lactic acid level, 12-hour lactic clearance, APACHE II score and blood pH had significant correlation with prognosis, odds ratios (OR) were 1.466, 0.922, 1.208, 0.032, respectively. Patients with peak lactic acid value> or =10 mmol/L or 12-hour lactic clearance< or =10% had significantly higher mortality: 77.8% and 70.6%, respectively (P<0.05 and P<0.01). Although patients with lacticemia>24 hours had higher mortality, there was no statistically significant difference. CONCLUSION: Peak lactic acid level, 12-hour lactic clearance, APACHE II score and blood pH are good indicators to evaluate patients' prognosis. Peak lactic acid value> or =10 mmol/L or 12-hour lactic clearance< or =10% is an alert of extremely bad prognosis. Prognosis value of duration of lacticemia is limited.

[Effect of total parenteral nutrition with supplementation of glutamine on the plasma diamine oxidase activity and D-lactate content in patients with multiple organ dysfunction syndrome].

OBJECTIVE: To explore the effect of total parenteral nutrition (TPN) supplemented with glutamine on the activity of plasma diamine oxidase (DAO) and D-lactate content in blood of patients with multiple organ dysfunction syndrome (MODS). METHODS: Forty patients with MODS in the intensive care unit (ICU) from September 2003 to June 2005 were involved in a randomized controlled study, and divided into routine group (group A, n=20), the glutamine +TPN treatment group (group B, n=20). All patients received equivalent nitrogen and caloric values in parenteral nutrition. Group A was given routine TPN, and group B was given extra glutamine 0.27 g.kg(-1).d(-1) (i. e. dipeptiven 0.4 g.kg(-1).d(-1)) for 7 days. The activity of plasma DAO and D-lactate content, the treatment time and the mortality rate of the two groups were determined before TPN, on the 1st, the 3rd and the 7th day after TPN. At the same time, 20 healthy blood donors formed the healthy control group (group C). All the data were analyzed with the SPSS 10.0 software. RESULTS: Before treatment, the activity of plasma DAO and D-lactate content of the two patient groups were significantly higher than those of group C (both P<0.01), and there was no difference between group A and group B (P>0.05). After the treatment of glutamine supplemented TPN, the activity of plasma DAO and D-lactate content of group B were lower than those of group A (both P<0.01). The duration of TPN was (15.8+/-2.3) days for group A and (12.5+/-2.4) days for group B. The former was significantly longer than that of group B (P<0.05). The mortality rate of group A was 25%, the mortality rate of group B was 10%, but there was no significant difference between the two groups (P>0.05). CONCLUSION: The glutamine (dipeptiven) supplementation through vein can help increase the supply of energy substrate to intestinal mucosa epithelium, and decrease the activity of plasma DAO and D-lactate content. It has an important effect on protecting the intestinal mucosa epithelial function. It also helps shorten the TPN treatment course.

[The research of related factors affecting the longevity of double chamber cardiac pacemaker].

OBJECTIVE: To research the related factors affecting the dual chamber cardiac pacemaker (PM) longevity, and provide the clinical basis for the PM reasonable application and design. METHODS: From 1991, 71 patients with AVB or SSS who used 9 kinds of dual-chamber PM were followed up. Every installed PM's related parameters, such as sensing electric current, resistance and pacing electric voltage, which may affect the PM longevity voltage had been recorded regularly. At the end point of survey, according to the related parameters of patients and PMs, the 71 patients were grouped into several groups. Then the related parameters were analyzed by statistical methods. RESULTS: The average of PM service life is 111 months +/- 19 months. Patient's basal heart rate, battery capacity, pacing electric voltage, pacing frequency, resistance, threshold value, pulse width and sensing electric current had all affected the PM's longevity (all P < 0.05) counted by Wilcoxon (Gehan) test. Sensing electric current (P = 0.000, RR = 3.072, 95% CI = 2.130 - 4.429), pacing electric voltage (P = 0.040, RR = 2.121, 95% CI = 1.126 - 3.998) and resistance (P = 0.049, RR = 1.786, 95% CI = 1.007 - 3.169) were the important predicting indictors of the PM longevity by Cox'proportional hazard risk regression analysis. CONCLUSION: Sensing electric current, pacing electric voltage and resistance are the important affecting factors of the PM longevity. Patient's basal heart rate, battery capacity, pacing frequency, threshold value and pulse width have influence of different degree on dual-chamber PM longevity.