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An estimated 258 million tons of plastic enter the soil annually. Joining persistent types of microplastic (MP), there will be an increasing demand for biodegradable plastics. There are still many unknowns about plastic pollution by either type, and one large gap is the fate and composition of dissolved organic matter (DOM) released from MPs as well as how they interact with soil microbiomes in agricultural systems. In this study, polyethylene MPs, photoaged to different degrees, and virgin polylactic acid MPs were added to agricultural soil at different levels and incubated for 100 days to address this knowledge gap. We find that, upon MP addition, labile components of low aromaticity were degraded and transformed, resulting in increased aromaticity and oxidation degree, reduced molecular diversity, and changed nitrogen and sulfur contents of soil DOM. Terephthalate, acetate, oxalate, and L-lactate in DOM released by polylactic acid MPs and 4-nitrophenol, propanoate, and nitrate in DOM released by polyethylene MPs were the major molecules available to the soil microbiomes. The bacteria involved in the metabolism of DOM released by MPs are mainly concentrated in Proteobacteria, Actinobacteriota, and Bacteroidota, and fungi are mainly in Ascomycota and Basidiomycota. Our study provides an in-depth understanding of the microbial transformation of DOM released by MPs and its effects of DOM evolution in agricultural soils.

In this work, the synthesis of magnetic recyclable catalyst (ZnFe2O4@PDA/COF@Pd) based on palladium nanoparticles immobilized on covalent organic framework (COF) carrier and polydopamine as the linking agent for zinc ferrite (ZnFe2O4) and COF is presented. The morphology, element composition, and surface energies of the compounds were characterized. The prepared ZnFe2O4@PDA/COF@Pd exhibits excellent catalytic activity for Suzuki coupling reaction under mild conditions (TON = 4.7 × 104, TOF = 4.7 × 104 h−1). In addition, p-nitrophenol can be completely reduced within 2–9 min in the presence of NaBH4. Besides, it has remarkable promoting effect on the degradation of dyes. The above characterizations and results indicate that COF is an ideal platform for homogeneously and dispersedly immobilizing Pd NPs, which prohibit the aggregation and leaching of Pd NPs. More importantly, in the recovery of p-nitrophenol reduction reaction, the yield of p-aminophenol can still reach more than 97% after five successive cycles, demonstrating the favorable stability and durability of ZnFe2O4@PDA/COF@Pd.ZnFe2O4@PDA/COF@Pd showed high activity in dye degradation and Suzuki reactions. The Kapp value of ZnFe2O4@PDA/COF@Pd in the reduction of p-NP was 0.0276 s−1. Polydopamine as a linker between ZnFe2O4 and COF enhanced the stability of the catalyst structure, resulting in excellent recovery efficiency and recyclability.

Attaining a synergistic merge between the performance of homogenous catalysts and the recyclability of heterogeneous catalysts remains until now a concerning issue. The main challenge is to design efficient, low-cost catalyst with outstanding reusability, facile recovery, and ease of retrieval and monitoring between the reuses. Despite the vast efforts in the development of silver nanoparticle–based catalyst for the reaction of hydrogenation of 4-nitrophenol, the aforementioned criteria are infrequently found in a chosen system. Herein, we report a MoS 2 nanosheet/silver nanoparticle–anchored PES-based textile as an efficient and recyclable “dip catalyst” for the 4-NP hydrogenation in the presence of sodium bohydride as model reaction. The textile fabric–based catalyst was processed via a simple sono-coating approach using MoS 2 nanosheets as first coating layer followed by an in situ deposition of silver nanoparticles. The “dip catalyst” fabric is rapidly and easily removed from the reaction and then reinserted in the batch system to attain over 10 reaction cycles. Additionally, the produced textile materials were characterized via spectroscopic and microscopic tools such as FTIR, XRD, SEM, and EDX. Moreover, the sources of the high catalytic activity are also discussed and a plausible reaction mechanism is suggested. The present study demonstrates the potential of metal nanoparticle-textile material combination for future applications in chemical sustainable catalysis for environmental remediation purposes. Graphical abstract

Background Bioremediation relying on highly efficient degrading bacteria constitutes a promising and sustainable avenue for controlling and reducing nitrophenol contamination in the environment. A thorough understanding of the bacterial degradation mechanism of nitrophenol is of paramount importance for supporting the development of efficient microbial remediation technology. Results In this study, a new bacterium, Rhodococcus sp. 21391, endowed with superior p -nitrophenol (PNP) degradation ability was obtained. Genomic and comparative proteomic analyses revealed that it utilizes the 1,2,4-benzenetriol (BT) pathway for PNP degradation. The catalytic properties of the two-component p -nitrophenol monooxygenase RsNcpAB from the strain were investigated in vitro. The enzyme exhibited a broad substrate selectivity, catalyzing the oxidation of various nitrophenols and halogenated phenols, with significant potential for further research and development. Additionally, the crystal structure of the oxidative component of p -nitrophenol monooxygenase, RsNcpA, was determined. Structural analysis and site-directed mutagenesis revealed that residues Arg100 and His293 in the active site play a crucial role in enzyme catalysis, and a catalytic mechanism model was subsequently proposed. Conclusions This study reports a high-performance nitrophenol-degrading bacterium and enzyme, and reveals their mechanisms at the molecular level. These findings increase the understanding of the bacterial degradation of nitrophenol, thereby providing a crucial foundation for the development of efficient bioremediation technologies. Graphical Abstract

Fe3O4/P(GMA-DVB)/PAMAM/Au microspheres are fabricated to research the catalytic performances to 4-nitrophenol. In the preparation process, Fe3O4 microspheres act as magnetic cores, PAMAM dendrimers growing up on the surface of P(GMA-DVB) polymer work as carriers, and Au nanoparticles serve as catalytic materials. The stability of the prepared microspheres is evaluated by successively catalytic experiments to measure the conversion of 4-nitrophenol, and catalytic efficiency can still maintain up to 78.7% after ten cycles. Moreover, the effects of major factors including the concentration of the prepared microspheres and the temperature of reaction system on the conversion of 4-nitrophenol are also investigated in detail. The manuscript reveals that 4-nitrophenol can be almost converted to 4-aminophenol within 7 min at 45 °C in the case of using 1.0 g/L Fe3O4/P(GMA-DVB)/PAMAM/Au microspheres. Such excellent catalytic properties are ascribed to the optimum structure of the prepared microspheres, which favors the sufficient contact between Au nanoparticles and 4-nitrophenol. The results and strategies exhibited here provide insight into the preparation of sophisticated structures of catalysts to treat wastewater.

Biochar is becoming a low-cost substitute of activated carbon for the removal of multiple contaminants. In this study, five biochar samples derived from pine sawdust were produced at different pyrolysis temperatures (300 °C–700 °C) and used adsorbents to remove p-nitrophenol from water. Results indicate that, as the pyrolysis temperature increases, the surface structure of biochar grows in complexity, biochar’s aromaticity and number of functional group decrease, and this material’s polarity increases. Biochar’s physiochemical characteristics and dosage, as well as solution’s pH and environmental temperature significantly influence the p-nitrophenol adsorption behavior of biochar. p-nitrophenol adsorption onto biochar proved to be an endothermic and spontaneous process; furthermore, a greater energy exchange was observed to take place when biochar samples prepared at high temperatures were utilized. The adsorption mechanism includes physical adsorption and chemisorption, whereas its rate is mainly affected by intra-particle diffusion. Notably, in biochar samples prepared at low temperature, adsorption is mainly driven by electrostatic interactions, whereas, in their high-temperature counterparts, p-nitrophenol adsorption is driven also by hydrogen bonding and π–π interactions involving functional groups on the biochar surface.

P-nitrophenol (PNP) is highly toxic and difficult to degrade, causing great harm to the ecological environment and human health. A two-stage bench-scale membrane biofilm reactor (MBfR) was constructed to treat wastewater containing high concentration of PNP and the generated nitrogen without external organic carbon sources. The two reactors were supplied with oxygen and methane, respectively. O2-MBfR was used for the degradation of PNP and the improvement of wastewater biodegradability. CH4-MBfR was used for the total nitrogen (TN) removal treatment from O2-MBfR effluent. In this experiment, the performance of the two-stage MBfR process was evaluated and optimized by adjusting operational parameters (aeration pressure, HRT, and pH). Under the optimal operation parameters, the removal efficiencies of PNP (100 mg/L) and TN attained 89.70% and 69.24%, respectively, and the removal loads were 0.930 g·m−2·d−1 and 241.42 mg·m−2·d−1, respectively. The reactor was able to accommodate the concentrations of PNP up to 200–400 mg/L, and the reactor reached maximum efficiency throughout the process when the concentration of PNP in the wastewater was 250 mg/L. The removal rates of PNP and TN reached 95.0% and 69.48%, respectively, and the removal loads were 2.37 g·m−2·d−1 and 96.22 mg·m−2·d−1, respectively. This research provides a better solution for multi-MBfR to treat toxic industrial wastewater containing phenol, nitrophenol, and further TN removal, which would not release any air pollutants into the atmosphere.

A simple, affordable and green method for synthesis gold (Au) and sliver (Ag) nanoparticles (NPs) has been adopted using Thyme plant (Thymus kotschyanus) extract. The plant extract, being rich in polyphenolic compounds, act as natural green reducing agent to generate noble metal NPs in situ from their corresponding ions. The structural and physical characteristics of the synthesized nanoparticles were ascertained over Ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Transmission electron microscopy (TEM) analysis. Both of the NPs displayed Surface Resonance Plasmon (SPR) excitation. The Synthesized Ag/Thyme NPs and Au/Thyme NPs catalytically explored in the reduction of 4-nitrophenol in presence of sodium borohydride as hydrogen donor. While used in different concentrations (100 µg/mL, 200 µg/mL and 300 µg/mL) as catalyst, it was seen that the activity gradually increased with higher catalyst load. The kinetic study of the reactions was also performed using the UV–Vis analysis data. All the reactions were of pseudo first order kinetics. The catalysts were isolated by centrifuge and recycled 6 successive times without any significant loss of its catalytic activity. As a result, at the same conditions, the reaction in the presence of Au NPs is faster than the reaction in the presence of Ag NPs. In summary, the noble gold and silver nanoparticles were synthesized over Thyme plant extract in a bio-inspired pathway.

Background: Widespread insecticide exposure might be a risk factor for neurodevelopment of our children, but few studies examined the mixture effect of maternal coexposure to organophosphate insecticides (OPPs), pyrethroids (PYRs), and neonicotinoid insecticides (NNIs) during pregnancy on child neurodevelopment, and critical windows of exposure are unknown. Objectives: We aimed to evaluate the association of prenatal exposure to multiple insecticides with children's neurodevelopment and to identify critical windows of the exposure. Methods: Pregnant women were recruited into a prospective birth cohort study in Wuhan, China, from 2014-2017. Eight metabolites of OPPs (mOPPs), three metabolites of PYRs (mPYRs), and nine metabolites of NNIs (mNNIs) were measured in 3,123 urine samples collected at their first, second, and third trimesters. Children's neurodevelopment [mental development index (MDI) and psychomotor development index (PDI)] was assessed using the Bayley Scales of Infant Development at 2 years of age (N = 1,041). Multivariate linear regression models, generalized estimating equation models, and weighted quantile sum (WQS) regression were used to estimate the association between the insecticide metabolites and Bayley scores. Potential sex-specific associations were also examined. Results: Single chemical analysis suggested higher urinary concentrations of some insecticide metabolites at the first trimester were significantly associated with lower MDI and PDI scores, and the associations were more prominent among boys. Each 1-unit increase in ln-transformed urinary concentrations of two mOPPs, 3,5,6-trichloro-2-pyridinol and 4-nitrophenol, was associated with a decrease of 3.16 points [95% confidence interval (CI): -5.59, -0.74] and 3.06 points (95% CI: -5.45, -0.68) respectively in boys' MDI scores. Each 1-unit increase in that of trans-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylic acid (trans-DCCA; an mPYR) was significantly associated with a decrease of 2.24 points (95% CI: -3.89, -0.58) in boys' MDI scores and 1.90 points (95% CI: -3.16, -0.64) in boys' PDI scores, respectively. Significantly positive associations of maternal urinary biomarker concentrations [e.g., dimethyl phosphate (a nonspecific mOPP) and desmethyl- clothianidin (a relatively specific mNNI)] with child neurodevelopment were also observed. Using repeated holdout validation, a 1-quartile increase in the WQS index of the insecticide mixture (in the negative direction) at the first trimester was significantly associated with a decrease of 3.02 points (95% CI: -5.47, -0.57) in MDI scores among the boys, and trans-DCCA contributed the most to the association (18%). Conclusions: Prenatal exposure to higher levels of certain insecticides and their mixture were associated with lower Bayley scores in children, particularly in boys. Early pregnancy may be a sensitive window for such an effect. Future studies are needed to confirm our findings.

Gadolinium hydroxide (Gd(OH) 3 ) was synthesized via a microwave-assisted synthesis method. Nickel ion (Ni 2+ ) was doped into Gd(OH) 3 , in which 4–12% Ni-Gd(OH) 3 was synthesized, to study the effect of doping. The structural, optical, and morphological properties of the synthesized materials were analyzed. The crystallite sizes of the hexagonal structure of Gd(OH) 3 and Ni-Gd(OH) 3 , which were 17–30 nm, were obtained from x-ray diffraction analysis. The vibrational modes of Gd(OH) 3 and Ni-Gd(OH) 3 were confirmed using Raman and Fourier-transform infrared spectroscopies. The band gap energy was greatly influenced by Ni-doping, in which a reduction of the band gap energy from 5.00 to 3.03 eV was observed. Transmission electron microscopy images showed nanorods of Gd(OH) 3 and Ni-Gd(OH) 3 and the particle size increased upon doping with Ni 2+ . Photocatalytic degradations of brilliant green (BG) and 4-nitrophenol (4-NP) under UV light irradiation were carried out. In both experiments, 12% Ni-Gd(OH) 3 showed the highest photocatalytic response in degrading BG and 4-NP, which is about 92% and 69%, respectively. Therefore, this study shows that Ni-Gd(OH) 3 has the potential to degrade organic pollutants.