Kvistdaniel1241

A structural equation model revealed that the main factors affecting seed germination were TOC (SM compost), acetic acid (SM+MS compost), humic acid (SM+CS compost), and pH (SM+GS compost). Low TOC and low molecular weight organic acids contents and higher humic acid content promoted GI. The research results could provide theoretical basis and measures for directional regulation of compost maturity.Metallic oxide nanoparticles (NPs) anchored in biochar provide a promising measure forward into the scaled-up application of these NPs in water treatment, and reducing the size of the dwelled NPs is expected to boost the adsorption performance of biochar-based composites because of the size and surface effect. Nevertheless, it is still of great challenge to regulate the size of the impregnated NPs due to their intrinsic self-agglomeration caused by high surface energy. In this study, we fabricated the charged biochar (C-BC) bearing high-density negatively charged groups (i.e., carboxyl and hydroxyl groups) via HNO3 oxidization to load the model metal oxide FeOOH NPs. Taurocholic acid manufacturer The average sizes of anchored FeOOH NPs were ultrasmall, ranging from 19.9 ± 1.5 to 3.1 ± 0.5 nm, and decreased with the increased amount of carboxyl and hydroxyl groups in C-BC. Whether in batch adsorption or fixed-bed column setting, adsorption of Cd(II) onto the as-made composites was greatly enhanced by carboxyl and hydroxyl groups in carrier. The normalized adsorption capacities of Cd(II) by ferric mass of the loaded FeOOH were 499.9-724.9 mg/g-Fe, approximately 18.6-27.1 and 2.51-3.64 folds over the bulky FeOOH and FeOOH-impregnated biochar. Our study results should provide a significant reference on how to acquire highly efficient biochar-based composites for water decontamination.Under anoxic conditions, aqueous Fe(II) (Fe(II)aq)-induced recrystallization of iron (oxyhydr)oxides changes the speciation and geochemical cycle of trace elements in environments. Oxidation of trace element, i.e., As(III), driven by Fe(II)aq-iron (oxyhydr)oxides interactions under anoxic condition was observed previously, but the oxidative species and involved mechanisms are remained unknown. In the present study, we explored the formed oxidative intermediates during Fe(II)aq-induced recrystallization of goethite under anoxic conditions. The methyl phenyl sulfoxide-based probe experiment suggested the featured oxidation by Fe(IV) species in Fe(II)aq-goethite system. Both the Mössbauer spectra and X-ray absorption near edge structure spectroscopic evidenced the generation and quenching of Fe(IV) intermediate. It was proved that the interfacial electron exchange between Fe(II)aq and Fe(III) of goethite initiated the generation of Fe(IV). After transferring electrons to goethite, Fe(II)aq was transformed to labile Fe(III), which was then transformed to Fe(IV) via a proton-coupled electron transfer process. This highly reactive transient Fe(IV) could quickly react with reductive species, i.e. Fe(II) or As(III). Considering the ubiquitous occurrence of Fe(II)-iron (oxyhydr)oxides reactions under anoxic conditions, our findings are expected to provide new insight into the anoxic oxidative transformation processes of matters in non-surface environments on earth.Superoxide radicals (O2•-) produced by the reaction of Fe(III) with H2O2 can regenerate Fe(II) in Fenton-like reactions, and conditions that facilitate this function enhance Fenton treatment. Here, we developed an efficient Fenton-like system by using calcium peroxide/biochar (CaO2/BC) composites as oxidants and tartaric acid-chelated Fe(III) as catalysts, and tested it for enhanced O2•--based Fe(II) regeneration and faster sulfamethoxazole (SMX) degradation. SMX degradation rates and peroxide utilization efficiencies were significantly higher with CaO2/BC than those with CaO2 or H2O2 lacking BC. The CaO2/BC system showed superior activity to reduce Fe(III), while kinetic analyses using chloroform as a O2•- probe inferred that the O2•- generation rate by CaO2/BC was one-half of that by CaO2. Apparently, O2•- is utilized more efficiently in this system to regenerate Fe(II) and enhance SMX degradation. Additionally, a positive correlation between SMX degradation rate constants and EPR signal intensities of biochar-derived persistent free radicals (PFRs) in CaO2/BC was obtained. We postulate that PFRs enhanced Fe(III) reduction by shuttling electrons donated by O2•-. This represents a new strategy to augment the ability of superoxide to accelerate Fe(III)/Fe(II) cycling for increased hydroxyl radical production and organic pollutant removal in Fenton-like reactions.The simultaneous removal of organic and inorganic pollutants from water requires multifunctional adsorbents. Cryogels of carboxymethyl cellulose (CMC) and sugarcane bagasse (BG) were modified with cetyltrimethylammonium bromide (CTAB) micelles for the adsorption of methylene blue (MB), Cr(VI) ions and bisphenol A (BPA) separately, in binary or ternary aqueous mixtures. Batch adsorption studies of MB and Cr(VI) and BPA on the CMCBG-CTAB adsorbents indicated removal capacities of 100%, 70% and 95%, respectively. MB adsorbed as multilayers on the CMCBG walls by electrostatic interaction, whereas Cr(VI) and BPA adsorbed on the cationic CTAB micelles surface and hydrophobic core of CTAB micelles, respectively. The breakthrough curves obtained for pure adsorbates and their mixtures showed that the adsorption of Cr(VI) ions increased (i) ~ 3.5 times in binary mixture with BPA or in the ternary mixture, in comparison to pure Cr(VI) solution, and (ii) 1.4 times in binary mixture with MB molecules, due to synergistic effects. In the presence of Cr(VI) ions in binary or ternary mixtures, the adsorption of MB was dramatically reduced due to screening effects. The adsorption of BPA was not significantly affected by the presence of MB or Cr(VI). The adsorbents were recycled five times without significant efficiency loss.Magnetically assembled electrode (MAE) flexibly attracts magnetic particles (auxiliary electrodes, AEs) on a main electrode (ME) by the magnetic force, where the role of ME is always ignored. In this study, Ti/Pt, Ti/RuO2-IrO2-TiO2 and Ti/Sb-SnO2 were selected as the ME for comparison in treating synthetic wastewater (acid red G or phenol) with variable Cl- content. The effects of ME type, loading amount of Fe3O4/Sb-SnO2 AEs, and Cl- concentration were investigated, followed by varied electrochemical characterizations. Results show that AEs played a vital role in electrode activity and selectivity, and MEs also exerted an unignorable influence on the performance of the MAEs. Among the three MEs, Ti/RuO2-IrO2-TiO2 has the best OER/CER ability, activating more extra active sites with same AEs loading amount, leading to higher organics degradation efficiency under chlorine-free condition. However, this MAE is featured by the noticeable accumulation of intermediate products under chlorine-free condition even if 0.3 g·cm-2 of AEs are loaded. All electrodes' performances were enhanced in the presence of Cl-. With high concentration chloride (0.5 M NaCl), the accumulation of intermediate products was reduced significantly, especially on Ti/RuO2-IrO2-TiO2 based MAE, and no chlorinated compound was identified. Finally, the structure-activity relationships of these MAEs were proposed.Domoic acid (DA) is a major marine neurotoxin, occurs frequently in most of the world's coastlines and seriously threatens ecosystem and public health. However, information on its biotransformation process in coastal anaerobic environments remains unclear. In this study, the underlying mechanism of anaerobic biotransformation of DA by marine consortium GLY was investigated using the combination of liquid chromatography-high-resolution Orbitrap mass spectrometry and comparative metatranscriptomics analysis. The results demonstrated that DA could be cometabolically biotransformed under anaerobic conditions with pseudo-first-order reaction. Anaerobic biotransformation pathway of DA was clarified, including decarboxylation, dehydrogenation, carboxylation activation with CoA and multiple β-oxidation steps occurring at aliphatic side chain, which facilitated DA detoxification. Furthermore, anaerobic cometabolic biotransformation mechanism of glycine-DA by consortium GLY was established for the first time, a number of genes related to the metabolic pathways of glycine fermentation, fatty acid synthesis and β-oxidation were responded in the consortium GLY transcriptome and involved in the anaerobic biotransformation of DA. This study could deepen understanding of interaction mechanism between toxin DA and marine microorganisms, which provides a new insight into the DA fate and its effects on benthic microbial community in marine environments.Covalent organic frameworks (COFs) with well-defined supramolecular structures and high surface-area-to-volume ratio have received extensive attention on their adsorption of contaminants from micro- to nano-size. Here, we studied the adsorption mechanisms of three typical nanoplastics (NP), including polyethylene (PE), nylon-6 (PA 6), and polyethylene terephthalate (PET) on chemically stable COFs (TpPa-X, X = H, CH3, OH, NO2 and F) by molecular dynamics simulations. Depending on molecular structure and surface composition, two distinct interactions-electrostatic interaction and van der Waals (vdW) interaction-are identified to be responsible for the adsorption of different NP pollutants on TpPa-X. The vdW interaction is dominant during the adsorption process, while polar groups in polymers and COFs can enhance the adsorption because of the electrostatic interaction. Compared with other functional COFs, we found that TpPa-OH shows the strongest adsorption with the NP pollutants employed in this study. This work reveals the COF-polymer adsorption behavior and properties at atomic scale, which is crucial to the development of promising COF materials to deal with NP pollution.Surface hydroxyl is widely perceived as conducive to HCHO degradation. Here, a kind of sodium titanate with interlayered hydroxyls (NaTi2HO5) was prepared to study the action conditions of surface hydroxyls in HCHO oxidation. The nanotubes mainly exposing (001) and nanobelts mainly exposing (100) are synthesized as the two morphologies of NaTi2HO5. We found the (001) facet is much more favored to HCHO adsorption via HRTEM and XPS analysis. The DFT calculations prove that the synergy of surface hydroxyl and Na atom is perfect for HCHO chemisorption. By this means NaTi2HO5 nanotubes can partially oxidize HCHO into formate and release very few CO, measured by in situ DRIFTS. Dominated by Pt nanoparticles, the complete oxidation of HCHO can be performed on NaTi2HO5 nanotubes with enhanced early reaction speed. Rather than simple surface hydroxyl, the effective synergy of hydroxyl and positive ion is proposed as an advantage for HCHO oxidation.Deep convolutional neural network (DCNN) has proved to be a promising tool for identifying organic chemicals of environmental concern. However, the uncertainty associated with DCNN predictions remains to be quantified. The training process contains many random configurations, including dataset segmentation, input sequences, and initial weight, etc. Moreover, the DCNN working mechanism is non-linear and opaque. To increase confidence to use this novel approach, persistent, bioaccumulative, and toxic substances (PBTs) were utilized as representative chemicals of environmental concern to estimate the prediction uncertainty under five distinguished datasets and ten different molecular descriptor (MD) arrangements with 111,852 chemicals and 2424 available MDs. An internal correlation coefficient test indicated that the prediction confidence reached 0.98 when a mean of 50 DCNNs' predictions was used instead of a sing DCNN prediction. A threshold for PBT categorization was determined by considering costs between false-negative and false-positive predictions.