Harvesting the Vibration Energy of BiFeO3 Nanosheets for Hydrogen Evolution.

In this study, mechanical vibration is used for hydrogen generation and decomposition of dye molecules, with the help of BiFeO3 (BFO) square nanosheets. A high hydrogen production rate of ≈124.1 µmol g-1 is achieved under mechanical vibration (100 W) for 1 h at the resonant frequency of the BFO nanosheets. The decomposition ratio of Rhodamine B dye reaches up to ≈94.1 % after mechanical vibration of the BFO catalyst for 50 min. The vibration-induced catalysis of the BFO square nanosheets may be attributed to the piezocatalytic properties of BFO and the high specific surface area of the nanosheets. The uncompensated piezoelectric charges on the surfaces of BFO nanosheets induced by mechanical vibration result in a built-in electric field across the nanosheets. Unlike a photocatalyst for water splitting, which requires a proper band edge position for hydrogen evolution, such a requirement is not needed in piezocatalytic water splitting, where the band tilting under the induced piezoelectric field will make the conduction band of BFO more negative than the H2 /H2 O redox potential (0 V) for hydrogen generation.

Aged polystyrene microplastics cause reproductive impairment via DNA-damage induced apoptosis in Caenorhabditis elegans.

Although polystyrene microplastics (PS-MPs) could induce toxic effects on environmental organisms, the toxicity of aged PS-MPs with H2O2 on soil organisms remains unclear. Our study utilized Caenorhabditis elegans as model organism to examine the reproductive toxicity of pristine PS-MPs (pPS-MPs) and aged PS-MPs (aPS-MPs) at environmentally relevant concentrations (0.1-100 µg/L). Acute exposure to aPS-MPs could induce greater reproductive impairment compared to pPS-MPs, as evidenced by changes in brood size and egg release. Assessment of gonad development using the number of mitotic cells, length of gonad arm, and relative area of gonad arm as parameters revealed a high reproductive toxicity caused by aPS-MPs exposure. Furthermore, aPS-MPs exposure promoted substantial germline apoptosis. Additionally, exposure to aPS-MPs (100 µg/L) markedly altered the expression of DNA damage-induced apoptosis-related genes (e.g., egl-1, cep-1, clk-2, ced-3, -4, and -9). Alterations in germline apoptosis caused by aPS-MPs were observed in mutants of cep-1, hus-1, egl-1, ced-3, -4, and -9. Consequently, the augmentation of reproductive toxicity resulting from aPS-MPs exposure was attributed to DNA damage-triggered cellular apoptosis. Additionally, the EGL-1-CEP-1-HUS-1-CED-3-CED-4-CED-9 signaling pathway was identified as a key regulator of germline apoptosis in nematodes. Our study provides insights into potential environmental risk of aPS-MPs with H2O2 on environmental organisms.

Significance of biotransformation and excretion on the enantioselective bioaccumulation of hexabromocyclododecane (HBCDD) in laying hens and developing chicken embryos.

Although (-)-α-hexabromocyclododecane (HBCDD) and (+)-γ-HBCDD are preferentially enriched in chickens, the key factors contributing to their selective bioaccumulation in hens and their potential biotransformation in developing chicken embryos remain unclear. Herein, in vivo and in ovo exposure experiments using hens and fertilized eggs were conducted to investigate the absorption, excretion, and biotransformation of HBCDDs in chickens. γ-HBCDD (76%) exhibited a higher absorption efficiency than α- (22%) and ß- (69%) HBCDDs. However, α-HBCDD was dominant in hen tissues, although γ-HBCDD accounted for >75% in the spiked feed. Moreover, chicken embryos biotransformed approximately 9.5% and 11.7% of absorbed α- and γ-HBCDDs, respectively, implying that diastereomer-selective elimination causes the predominance of α-HBCDD in hens. The concentration and enantiomer fraction (EF) of α-HBCDD in laid eggs were significantly positively correlated, suggesting enantioselective elimination. The EFs of α- and γ-HBCDDs varied between feces from the exposure and depuration periods, indicating the preferred excretion of (+)-α- and (-)-γ-HBCDDs. Furthermore, the enantioselective biotransformation of (-)-γ-HBCDD was confirmed in developing chicken embryos. These results show that excretion and biotransformation contribute to the diastereomer- and enantiomer-selective bioaccumulation of HBCDDs in chickens; The results may improve our understanding of the environmental fate and ecological risks of HBCDDs in biota.

Biochar for simultaneously enhancing the slow-release performance of fertilizers and minimizing the pollution of pesticides.

Biochar has been extensively studied as a promising carrier material for fertilizers and an ideal adsorbent for the removal of pesticides. Yet, the application of biochar for simultaneously eliminating the pollution from the agricultural use of fertilizers and pesticides remains unexplored. Herein, we develop P-loaded biochar-based fertilizers (PBC) by the co-pyrolysis of cotton straw and H3PO4. The slow-release performance of PBC and their adsorption properties toward pesticides are investigated. The results indicate that the PBC leads to the improvement of adsorption performance, with the maximum adsorption capacities of lambda-cyhalothrin (LAC) for PBC and pristine biochar are 55.90 mg/g and 42.71 mg/g, respectively. Additionally, the adsorption of LAC is beneficial for the improvement of slow-release performance of PBC. The release ratios of P from PBC within 30 days reach 100.0% and 83.5% in water and LAC solution, respectively, demonstrating the existence of synergistic effects between the adsorption of pesticides and the slow release of nutrients. The mechanistic investigation reveals that the pretreatment of H3PO4 facilitates to activate more surface functional groups of PBC, contributing greatly to the improved adsorption of LAC. The adsorption of LAC reduces the BET of PBC with pore filling, enabling slower release rate of nutrients from PBC.

Synthesis and characterization of Ni-doped anatase TiO2 loaded on magnetic activated carbon for rapidly removing triphenylmethane dyes.

In this work, we employed the in situ synthesis method to implant Fe3O4 into activated carbon (AC), in which the synthesis of the magnetic AC (MAC) was realized. Thence, Ni-doped anatase TiO2 (NATiO2) were anchored on different addition amount of MAC to synthesize the series of Ni-TiO2/MAC photocatalysts. The chemical compositions and physical properties of these nanocomposites were analyzed by various characterization technologies. The photocatalytic capabilities of as-produced materials were then investigated via adsorption and photodegradation of triphenylmethane dyes (TPMs) as crystal violet (CV), basic fuchsine (BF), and malachite green (MG) solution. The results revealed that the removal of Ni-TiO2/AC, Ni-TiO2/2MAC, Ni-TiO2/4MAC, and Ni-TiO2/8MAC on TPMs is a very fast process and the removal efficiency can almost reach to about 90% in 10 min, and the catalyst has good cycle stability and is easy to be reused. This work provides a novel, low-cost, and effective way to rationally design and synthesize TiO2-based photocatalysts for effective removal of TPMs.

Organophosphate flame retardants and diesters in the urine of e-waste dismantling workers: associations with indoor dust and implications for urinary biomonitoring.

Indoor dust ingestion is one of the main pathways for human exposure to organophosphate flame retardants (PFRs). The urinary concentrations of diesters (DAPs) are usually used as biomarkers to assess human exposure to PFRs. In this study, the PFR and DAP levels were measured in morning and evening urine samples of 30 workers from an e-waste dismantling site in southern China. The indoor dust samples were also collected from workshops and houses for analyzing associations between PFR and DAP levels in urine and dust. Tris(1-chloro-2-propyl) phosphate (TCIPP) and triphenyl phosphate (TPHP) were the dominant PFRs in dust, while bis(2-chloroethyl) phosphate (BCEP) and diphenyl phosphate (DPHP) were the major DAPs in dust. A significant positive correlation was observed between TPHP and DPHP concentrations in dust (p < 0.001), suggesting their potentially same source and the degradation of TPHP to form DPHP. TCIPP and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) were the predominant PFRs, and BCEP, bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), and DPHP were the main DAPs in both the morning and evening urine samples. The DPHP levels in evening urine samples were significantly correlated with TPHP and DPHP levels (p < 0.01) in dust. A similar correlation was found for the BCEP levels in the evening urine samples and the TCEP and BCEP levels (p < 0.01) in dust. These results indicated that in addition to being biotransformed from their respective parent PFRs, direct ingestion from indoor dust could also be the potential source for urinary DPHP and BCEP. Since relatively low detection frequencies were observed for bis(1-chloro-2-propyl) phosphate (BCIPP) and bis(butoxyethyl) phosphate (BBOEP) in urine, they may not be the major metabolites of TCIPP and tris(2-butoxyethyl) phosphate (TBOEP), respectively, in the human body. However, BDCIPP can be considered a useful biomarker because it is a unique metabolite of TDCIPP and has high detection frequencies in urine samples. The results of this study indicated the limitations of solely using urinary DAPs as biomarkers for the evaluation of human exposure to PFRs, and certain PFRs as well as hydroxylated PFRs (OH-PFRs) should also be considered for urinary biomonitoring in future studies.

Synthesis of Ni-doped anatase TiO2 single crystals loaded on wood-based activated carbon for enhanced photodegradation of triphenylmethane dyes.

In this work, the Ni-doped anatase TiO2 single crystals loaded on activated carbon (Ni-T/AC) were synthesized by a sol-gel method. The chemical compositions and physical properties of as-prepared materials were analyzed by XRD, TEM, BET, FTIR, XPS, and PL characterizations. The obtained results implied that all of samples presented anatase phase with a clear mesoporous structure. The photocatalytic properties of nanocomposites were evaluated through photodegradation of crystal violet (CV), basic fuchsine (BF), and malachite green (MG). The results revealed that the catalyst Ni-T/AC-loaded AC exhibited an excellent photocatalytic activity compared with the original TiO2, and the photodegradation efficiency for CV, BF, and MG is 99.00%, 94.85%, and 98.89% after 120 min of irradiation, respectively. This enhancement may be ascribed to the small crystallite size, large specific surface area, and pore volume of the photocatalysts. In addition, the possible degradation mechanism and pathway for triphenylmethane dyes (TPMs) were also well investigated. This work provides a new, low-cost, and effective route to improve the performance of TiO2 for effective removing TPMs.

Determination of the Contents of Antioxidants and Their Degradation Products in Sodium Chloride Injection for Blood Transfusion.

The infusion bag is mainly made up of polyolefin polymer. Antioxidants are usually added to these polymer materials in the production process to prevent the materials from aging and enhance the stability of the materials. Because of the potential harm of antioxidants to human body, it is necessary to limit the amount of antioxidants migrating to the pharmaceutical solutions. In the present study, we developed and validated the HPLC method for the simultaneous quantification of antioxidants and their degradation products migrating to sodium chloride solution for injection. A total of six antioxidants and six their degradation products were separated and simultaneously determined by using a Waters Symmetry RP18 column (250 × 4.6 mm, 5 µm) and gradient elution of methanol/acetonitrile/acetic acid-water (1 : 99, v/v) at a flow rate of 1.0 mL/min. The detective wavelength was set at 277 nm, and the column temperature was maintained at 35°C. The method was validated in terms of limit of detection (LOD, 0.011-0.151 µg/mL), limit of quantification (LOQ, 0.031-0.393 µg/mL), intraday precision (0.25%-3.17%), interday precision (0.47%-3.48%), linearity (0.1-46.8 µg/mL, r > 0.9994), stability (0.35%-3.29%), and accuracy (80.39%-104.31%). In the extraction experiment, antioxidants, BHT, 1010, 1330, 1076, and 168, and their degradation products, 1310 and DBP, were detected in the packaging materials. Only 1310 was detected in the migration experiment. The maximum daily dosage of sodium chloride for blood transfusion is three bags, and the content of 1310 in long-term testing samples is from 0 to 12 months ranging from 37.44 µg/3 bags to 48.71 µg/3 bags. The daily intake of 1310 did not exceed 48.71 µg, which was much lower than its permitted daily exposure (PDE, 300 µg/day). Therefore, the antioxidants and their degradation products migrating into the drug solution would not cause drug safety risks.

High-efficient synergy of piezocatalysis and photocatalysis in bismuth oxychloride nanomaterial for dye decomposition.

In this work, it is found that the hydrothermally-synthesized bismuth oxychloride can behave both the piezocatalysis and photocatalysis for the Rhodamine B dye decomposition. ∼99% decomposition efficiency is achieved after both vibrating and lighting the Rhodamine B dye solution for ∼96 min with the addition of bismuth oxychloride catalyst, while the ∼72% and ∼26% decomposition efficiencies are obtained for only photocatalysis or only piezocatalysis respectively. In bi-catalysis, the mechanical strain produced due to vibration will directly provide an electric field that will increase the separation between the photo-induced electron-hole pairs, yielding to the enhanced decomposition performance of bi-catalysis. There is no significant change in the bi-catalytic performance of bismuth oxychloride nanomaterial observed after being recycled four times. Bismuth oxychloride catalyst is potential for the bi-catalytic decomposition treatment of wastewater through harvesting both the environmental vibration energy and light energy.

Isoelectric focusing sample injection for capillary zone electrophoresis in a fused silica capillary.

An improvement has been made to couple isoelectric focusing (IEF) sample injection and capillary zone electrophoresis in an untreated fused silica capillary. Electroosmotic flow is efficiently prevented by simply using a rubber block at the outlet end of the capillary during IEF sample injection. The experimental conditions that affect the concentration effect are discussed. A concentration enhancement factor of over 100-fold can be easily obtained for two model proteins: lysozyme and ribonuclease A.

[Determination of alkyl-phenols in textiles by in-tube capillary solid-phase extraction-gas chromatography].

An in-tube capillary solid-phase extraction (SPE) -gas chromatography (GC) method was developed for confirmation and quantitative determination of octylphenol (OP) and nonylphenol (NP) in textiles. To make the in-tube capillary SPE column, the best SPE cartridge was chosen from four kinds of SPE cartridges. The adsorbent in the cartridge was used as the filling material to make the in-tube capillary SPE column. The nature, volume used, flow rate and adsorption capacity of the eluent were compared. Finally, the in-tube capillary solid-phase extraction was combined with gas chromatography to detect the alkyl phenols (APs). Abselut NEXUS extraction cartridge was chosen as the best solid phase extractant. The optimal in-tube capillary SPE extraction conditions were as follows: 1.2 µL methanol and 1.2 µL ultra-pure water for activating the extraction column, 1.2 µL methanol for eluting, 0.4 µL/min for solution loading. The method showed a good linear relationship in the low concentration range, and the enrichment ratios for the APs were about 100 times. The detection limits of octylphenol and nonylphenol were 3.7 µg/L and 4.5 µg/L, respectively. The recoveries of octylphenol were 85.6%-98.2%, and those of nonylphenol were 83.8%-95.7%. The experimental results demonstrated that the method is simple, rapid, and useful for detecting APs in textiles.

Capillary electrophoresis with in-capillary solid-phase extraction sample cleanup.

An in-capillary, solid-phase extraction (SPE)-capillary electrophoresis (CE) method, with not only high preconcentration factor but also no adsorption on the inner capillary wall of absorbing species in real complex samples, has been developed with a hole-opened capillary. The SPE sorbents approximately 3 mm in length was packed in the inlet end of the capillary. A hole approximately 30 microm in diameter was opened after the sorbents on the capillary. Sample solutions were loaded from the inlet end, and the sample wastes flowed out from the hole. After a certain time of the sample loading, a 1.5-mm-long methanol plug was introduced from the inlet end and forced to pass by the sorbents and the hole. Then, a separation voltage was applied between the hole and the outlet end of the capillary to carry out normal CE. When the sample loading time was 120 min, CE peak heights of the 2,4-dichlorophenol and 2,4,5-trichlorophenol were proportional to their concentration in a range of 0.08-5 ng/mL, and their detection limits were 25 and 17 pg/mL, respectively. A 16,000-fold sensitivity enhancement was obtained for CE of the chlorophenols with only a little decrease in CE separation efficiency. It was also demonstrated with the mixture of the chlorophenols and a surfactant cetyltrimethylammonium bromide that the present method could eliminate the adsorption problem of absorbing species on the inner wall during sample loading. Furthermore, the SPE-CE was directly applied to determination of chlorophenols on the level of 0.02 ppb in downstream water of a river, and the results agreed well with those obtained with off-line SPE-HPLC experiments.

In-capillary solid-phase extraction-capillary electrophoresis for the determination of chlorophenols in water.

A novel CE method combined with SPE in a single capillary was developed for analysis of chlorophenols in water. A frit of 0.5 mm was first made by a sol-gel method, followed by packing a SPE sorbent in the inlet end of the capillary. Two phenol derivatives, 2,4-dichlorophenol and 2,4,5-trichlorophenol, were used as the model compounds. By loading sample solutions into the capillary, the two chlorophenols were extracted into the sorbent. They were desorbed by injecting only about 4 nL of methanol. Finally, the analytes were separated by conventional CE. The technique provided a concentration enhancement factor of over 4000-fold for both chlorophenols. The detection limits (S/N = 3) of 2,4-dichlorophenol and 2,4,5-trichlorophenol were determined to be 0.1 ng/mL and 0.07 ng/mL, respectively. For replicate analyses of 5 ng/mL of 2,4-dichlorophenol, within-day and between-day RSDs of migration time, peak height and peak area were in the range of 1.8-2.0%, 4.0-4.4% and 4.1-4.6%, respectively. The method shows wide linear range, acceptable reproducibility and excellent sensitivity, and it was applied to the analyses of spiked river water samples. The capillary packed with the SPE sorbents can be used for more than 400 runs without performance deterioration.

Isoelectric focusing sample injection for capillary electrophoresis of proteins.

Carrier ampholyte-free isoelectric focusing (IEF) sample injection (concentration) for capillary electrophoresis (CE) is realized in a single capillary. A short section of porous capillary wall was made near the injection end of a capillary by HF etching. In the etching process, an electric voltage was applied across the etching capillary wall and electric current was monitored. When an electric current through the etching capillary was observed, the capillary wall became porous. The etched part was fixed in a vial, where NaOH solution with a certain concentration was added during the sample injection. The whole capillary was filled with pH 3.0 running buffer. The inlet end vial was filled with protein sample dissolved in the running buffer. An electric voltage was applied across the inlet end vial and etched porous wall. A neutralization reaction occurs at the boundary (interface) of the fronts of H+ and OH-. A pH step or sharp pH gradient exists across the boundary. When positive protein ions electromigrate to the boundary from the sample vial, they are isoelectricelly focused at points corresponding to their pH. After a certain period of concentration, a high voltage is applied across the whole capillary and a conventional CE is followed. An over 100-fold concentration factor has been easily obtained for three model proteins (bovine serum albumin, lysozyme, ribonuclease A). Furthermore, the IEF sample concentration and its dynamics have been visually observed with the whole-column imaging technique. Its merits and remaining problem have been discussed, too.