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The concentrations of chlorophyll and carotenoids were analyzed in two organs (leaves and bolting stems) of 19 varieties of Chinese kale (including four maturity periods and two flower colors). Two chlorophylls and four carotenoids were identified in Chinese kale. The concentrations of chlorophyll and carotenoids varied widely in different organs and varieties. JL-03 was a good candidate for the future breeding programs, since it contained the highest concentrations of chlorophyll and carotenoids (except violaxanthin) in leaves. Lutein was the main component of carotenoids and accounted for approximately 50% of total carotenoids. The concentrations of chlorophyll and carotenoids in leaves significantly exceeded those in bolting stems. Principal component analysis showed that organ was the main source of differences of chlorophyll and carotenoid concentrations in different varieties of Chinese kale, while the maturity and flower color have little effect. Correlation analysis identified a significantly positive correlation between chlorophyll and carotenoids in Chinese kale. These results provided evidence for improving human dietary nutrition and breeding of Chinese kale.

A novel mechanochemically assisted persulfate activation method was proposed in this study to enhance the leaching of valuable metals from lithium-ion batteries by combining ball-milling, advanced oxidation processes and sucrose reduction. By optimizing leaching parameters including temperature, pH, milling time and solid-to-liquid ratio, high leaching efficiencies of 97.1%, 94.0%, 87.6% and 93.8% can be achieved for Li, Ni, Co and Mn respectively. In the mechanochemical process, the breakage of covalent bonds in cathode material is facilitated by free radicals generated from zero valent iron activated ammonia persulfate as well as mechanochemical activation. To further explore the role of free radicals, the mechanism of ammonia persulfate activation by zero valent iron was elucidated, and SO

Ventilation is an efficient approach employed for accelerating stabilization and reducing aftercare of landfill, but its effect on leachate reduction is still elusive. To fill this knowledge gap, five lab-scale landfill reactors with different ventilation rates were established in this study. Suitable ventilation (e.g. 0.25-0.5 L·min

Developing efficient catalysts with low cost and environmental friendliness for peroxymonosulfate (PMS) activation attracts broad interest. In this study, TiO

Enhancements in the light response and hydrogen peroxide utilization are critical to the catalytic performance of heterogeneous Fenton-like perovskites. Here, in this research, oxygen vacancy-enriched La

The narrow acid pH range and the nonselectivity of the dominant •OH limit the Fenton systems to remediate the organic wastewater. Inspired by the role of heme in physiological processes, we employed iron porphyrin as a novel homogeneous catalyst to address this issue. Multiple active species are identified during the activation of H

Here the role of microplastic size on dissolved organic matter, leaching compounds and microbial community during anaerobic sludge digestion was evaluated. Compared to that without the addition of polyvinyl chloride (PVC), during the 30 days' incubation, the anaerobic sludge digestion by adding PVC at the size of 75 μm and the concentration of 2.4 g/g volatile solids (VS) showed a 8.5% lower cumulative methane production, while a 17.9% higher cumulative methane production was noted by adding PVC at the size of 3000 μm and the concentration of 2.4 g/g VS. A long-term fed-batch laboratory-scale fermenter test for 147 days further testified, that higher removal efficiencies of total solids, volatile solids, and total chemical oxygen demand, and higher methane production were noted by adding PVC (2.4 g/g VS, 3000 μm) into the fermenter. More interestingly, higher concentrations of proteins, polysaccharides, volatile fatty acids, and soluble microbial by-products component were noted in the liquid phase of sludge drawn from the fermenter added with PVC since the biomass therein showed higher efficiencies of solubilization, hydrolysis, acidification, and methanogenesis. Moreover, as identified from the fermenter added with PVC, dibutyl phthalate (DBP) was the most predominant leaching phthalates compound, although the biomass therein showed a 93.4% anaerobic biodegradability of DBP. The leaching of DBP drove the predominance of microbial community towards Synergistota and Methanosaeta. More irregular elliptical shallow dimples were noted on the PVC surface after 147 days' incubation, accompanied with abundances of Proteobacteria, Actinobacteriota, Chloroflexi, Methanosaeta and Methanobacterium. The results from this study showed that the size of microplastic was a crucial factor in evaluating its impact on anaerobic sludge digestion.

Lithium ion batteries have been undergoing rapid development in the global market due to their superior performance. However, the soaring number of lithium ion batteries in the market presents serious disposal challenges at the end of life. Moreover, continuous mining processes are harmful to the environment. From the viewpoint of cleaner production and green chemistry, the efficient recovery and reutilization of spent lithium ion batteries are necessary. In this perspective, the overall process of lithium ion battery recycling, especially the recent advances of hydrometallurgical methods, are summarized, focusing on the leaching, separation, and purification processes. The proper disposal of the waste discharged during the recycling process is proposed, highlighting the mitigation of secondary pollution. In addition, the environmental impact of recycling processes is summarized and thoroughly evaluated by recent life cycle assessment studies, revealing the key role of recycling strategic metal elements toward sustainability in an anthropogenic cycle. Finally, the current challenges in this area are pointed out and perspectives on sustainable approaches, cleaner production, and life cycle assessment are proposed.

Plant invasion is one of the most serious threats to ecosystems worldwide. When invasive plants with the ability of clonal growth invading or colonizing in new habitat, their interconnected ramets may suffer from heterogeneous light. Effects of clonal integration on allelopathy of invasive plants are poorly understood under heterogeneous light conditions. To investigate the effects of clonal integration on allelopathy of invasive plant Wedelia trilobata under heterogeneous light conditions, a pot experiment was conducted by using its clonal fragments with two successive ramets. The older ramets were exposed to full light, whereas the younger ones were subjected to 20% full light. The younger ramets of each clonal fragment were adjacently grown with a target plant (one tomato seedling) in a pot. Stolon between two successive ramets was either severed or retained intact. In addition, two tomato seedlings (one as target plant) were adjacently grown in a pot as contrast. Compared with severing stolon, biomass accumulation, foliar chlorophyll and nitrogen contents, chlorophyll fluorescence parameters and net photosynthetic rates of the target plants as well as their root length and activity, were significantly decreased when stolon between interconnected ramets of W. trilobata retained intact. Under heterogeneous light conditions, transportation or sharing of carbohydrate between two successive ramets enhanced allelopathy of the young ramets subjected to 20% full light treatment. It is suggested that clonal integration may be important for invasion or colonization of invasive plants with ability of clonal growth under heterogeneous light conditions.

Extracellular polymeric substance (EPS) is recognized as a critical component that determines sludge dewaterability. In this study, a layer by layer degradation of EPS was confirmed for the first t...

SUMMARY Research background. Depression has become a global threat to human health. In order to solve it, researchers have conducted multi-faceted studies including diet. Many food-derived bioactive substances have shown antidepressant effects. However, there are few studies on the design of industrialized food with antidepressant effect. This study aimed to evaluate the antidepressant effect of a functional beverage made from several ingredients with potential antidepressant function and investigate its antidepressant mechanisms. Experimental approach. The beverage consists of peppermint oil, active peptides derived from bovine milk casein and Acanthopanax senticosus extract (ASE) whose active ingredient is eleutheroside. Different amounts of ASE were evaluated to determine the optimal concentration of eleutheroside in this functional beverage to deliver best antidepressant effect through extensive behavioral testing including preliminary acute stress experiments and further chronic unpredictable mild stress test. Results and conclusions. The results demonstrated that the beverage with 15.00 mg/kg of eleutheroside could significantly reduce the mice’s immobility time of tail suspension test and forced swimming test, recover mice’s sucrose preference and behavior changes in the open-field test, improve the contents of dopamine, norepinephrine, 5-hydroxytryptamine and the activity of superoxide dismutase and reduce the content of malondialdehyde in mice’s brains, which indicated that the improvement of monoamine neurotransmitter systems and antioxidation was one potential mechanism of antidepressant action. Novelty and scientific contribution. This study provides a design of antidepressant functional beverage and an efficient way for the prevention and treatment of depression.

Power overshoot that presents in the power curves of microbial fuel cells (MFCs) is one of the main reasons for the deterioration of MFC performance over the high current region. In this research, the mechanisms of power overshoot were investigated with single-chamber MFCs integrated with carbon cloth anode and Fe/N-doped carbon cathodes possessing varied capacitance properties. It was revealed that insufficient anodic current produced at high potential is responsible for power overshoot generation, which could be eliminated with higher capacitive cathode (7.79 F) compared with the one with lower capacitive cathode (3.74 F). This elimination can be ascribed to the improvement of MFC capacitance induced by cathode capacitance, which was proved by MFC charge-discharge test. However, cathode capacitance can only increase the MFC capacitance to a limited extent, as power overshoot can still occur when applying long stabilization time for polarization test.

Cathode oxygen reduction reaction (ORR) performance is crucial for power generation of microbial fuel cells (MFCs). The current study provides a novel strategy to prepare Fe/N-doped carbon (Fe/N/C) catalyst for MFCs cathode through high temperature pyrolyzing of biomass capsuling melamine resin polymer. The obtained Fe/N/C can effectively enhance activity, selectivity and stability toward 4 e– ORR in pH neutral solution. Single chamber MFC with Fe/N/C air cathode produces maximum power density of 1166 mW m−2, which is 140% higher than AC cathode. The improved performance of Fe/N/C can be attributed to the involvement of nitrogen and iron species. The excellent stability can be attributed to the preferential structure of the catalyst. The moderate porosity of the catalyst facilitates mass transfer of oxygen and protons and prevents water flooding of triple-phase boundary where ORR occurs. The biomass particles encapsulated in the catalyst act as skeletons, which prevents catalyst collapse and agglomeration.

The dysregulation of tryptophan-kynurenine pathway (TKP) is extensively involved in the pathophysiology of Alzheimer's disease, depression, and neurodegenerative disorders. Minocycline, a classic antibiotic, may exert psychotropic effects associated with the modulation of TKP. In this study, we examined the effects of minocycline in improving behaviour and modulating TKP components in chronically stressed male mice. Following repeated treatment with 22.5 mg/kg and 45 mg/kg minocycline for 27 days, the stressed mice particularly with higher dose displayed significant improvement on cognitive impairment, depression- and anxiety-like behaviour. Minocycline suppressed stress-induced overexpression of pro-inflammatory cytokines and restored anti-inflammatory cytokines. Chronic stress dramatically suppressed blood and prefrontal cortical levels of the primary substrate tryptophan (TRP), the neuroprotective metabolite kynurenic acid (KYNA), and KYNA/KYN ratio, but increased the intermediate kynurenine (KYN), 3-hydroxykynurenine (3-HK), KYN/TRP ratio, and the neurotoxic metabolite quinolinic acid (QUIN). Minocycline partially or completely reversed changes in these components. Minocycline also inhibited stress-induced overexpression of QUIN-related enzymes, indoleamine 2, 3-dioxygenase 1(iDO-1), kynureninase (KYNU), kynurenine 3-monooxygenase (KMO), 3-hydroxyanthranilate 3,4-dioxygenase (3-HAO), but rescued the decreased expression of kynurenine aminotransferase (KAT) in brain regions. Behavioral improvements were correlated with multiple TKP metabolites and enzymes. These results suggest that the psychotropic effects of minocycline are mainly associated with the restoration of biodistribution of the primary substrate in the brain and normalization of neuroinflammation-evoked TKP dysregulation.

Hemin has attracted considerable interest as an efficient catalyst recently, however, its direct application is inefficient due to severe molecular aggregation. Immobilizing hemin on various supports is a feasible approach to address this issue. In this work, a CNTs-hemin catalyst was prepared by loading hemin onto multiwalled carbon nanotubes (CNTs) through ball milling. Compared with hemin, CNTs-hemin demonstrates remarkably enhanced performance in the peroxymonosulfate system, with a 650-fold improvement of apparent rate constant, reaching 97.8% degradation of sulfathiazole in 5 min. High-valent iron-oxo porphyrin cation ((Porp)

Arsenic-alkali residue (AAR) from antimony production can pose significant health and environmental hazards due to the risk of arsenic (As) leaching. In this study, geopolymer composite synthesized from fly ash (FA) was investigated for efficient stabilization of high-arsenic-containing AAR (As

This study compared effects of three different valent iron (Fe0, Fe(II) and Fe(III)) on enhanced anaerobic sludge digestion, focusing on the changes of oxidation reduction potential (ORP), dissolved organic nitrogen (DON), and microbial community. Under the same iron dose in range of 0–160 mg/L after an incubation period of 30 days (d), the maximum methane production rate of sludge samples dosed with respective Fe0, Fe(II) and Fe(III) at the same concentration showed indiscernible differences at each iron dose, regardless of the different iron valence. Moreover, their behavior in changes of ORP, DON and microbial community was different: (1) the addition of Fe0 made the ORP of sludge more negative, and the addition of Fe(II) and Fe(III) made the ORP of sludge less negative. However, whether being more or less negative, the changes of ORP may show unobservable effects on methane yield when it ranged from −278.71 to −379.80 mV; (2) the degradation of dissolved organic nitrogen, particularly proteins, was less efficient in sludge samples dosed with Fe0 compared with those dosed with Fe(II) and Fe(III) after an incubation period of 30 d. At the same dose of 160 mg/L iron, more cysteine was noted in sludge samples dosed with Fe(II) (30.74 mg/L) and Fe(III) (27.92 mg/L) compared with that dosed with Fe0 (21.75 mg/L); (3) Fe0 particularly promoted the enrichment of Geobacter, and it was 6 times higher than those in sludge samples dosed with Fe(II) and Fe(III) at the same dose of 160 mg/L iron.

This study investigated the effects of electrical signaling disruption induced by adding tetraethylammonium (TEA, a potassium channel blocker) on the formation of mixed-cultured electroactive biofilms, especially the relative abundance of Geobacter over time. Results showed that TEA addition decelerated the biofilm formation, but selectively enriched Geobacter over time (45.8% on Day 32, 67.7% on Day 60 and 78.1% on Day 90), thus resulting in higher final extracellular electron transfer (EET) efficiency. Redundancy analysis (RDA) confirmed that TEA and operation time were significant factors for the selective enrichment of Geobacter. Moreover, increase in cellular processes and signal processing by PICRUSt analysis indicated adaptive responses of electrogenic biofilms to electrical signaling disruption. Furthermore, qRT-PCR indicated the compensatory roles of key cytochromes and pilA in electrochemical communication, which induced Geobacter enrichment. This work provided a broader understanding of electroactive biofilm regulation and potential applications for electricity generation and biosensor in the future.

This study investigated a novel sodium iron chlorophyllin-H

A microbial fuel cell-photocatalysis system with a novel photocatalytic air-cathode (MFC-PhotoCat) was proposed for synergistic degradation of 2,4,6-trichlorophenol (TCP) with simultaneous electricity generation. Stable electricity generation of 350 mV was achieved during 130 days of operation. Besides, 50 mg L−1 TCP was completely degraded within 72 h, and the rate constant of 0.050 h−1 was 1.8-fold higher than MFC with air-cathode without N-TiO2 photocatalyst. Degradation pathway was proposed based on the intermediates detected and density functional theory (DFT) calculation, with two open-chain intermediates (2-chloro-4-keto-2-hexenedioic acid and hexanoic acid) detected. Furthermore, hierarchical cluster and PCoA revealed significant shifts of microbial community structures, with enriched exoelectrogen (55.2% of Geobacter) and TCP-degrading microbe (7.1% of Thauera) on the cathode biofilm as well as 61.8% of Pseudomonas in the culture solution. This study provides a promising strategy for synergic degradation of recalcitrant contaminants by intimate-coupling of MFC and photocatalysis.

Biological wastewater treatment generates a large quantity of sewage sludge that requires proper treatments. In this study, the biochar pyrolyzed by sludge conditioned with Fenton's reagent and lime (referred to as Fenton-lime system) was first used as an efficient silicon fertilizer for rice cultivation. When the pyrolysis temperature was 750 °C, the dissolved silicon and available silicon contents in biochar derived from sludge conditioned with Fenton-lime system were much higher than those in raw sludge derived biochar without conditioning (3.49 vs. 0.72, 77.25 vs. 2.33 mg/g dry solid, respectively). The enhanced available silicon content was attributed to the newly formed calcium aluminosilicate from the reactions between the added lime and silicon-rich phases in sludge. The rice cultivated with biochar derived from Fenton-lime conditioned sludge showed improved biomass of stem and root by 76.85% and 36.11%, respectively, compared to blank group without the addition of Si source. Heavy metals and the reactive oxygen species (ROS) accumulation in rice were not observed after a culture period of 30 days in the application of sludge-derived biochar as silicon fertilizer. This study provides a promising approach for sewage sludge recycling as an efficient silicon fertilizer in silicon-deficiency land.

Many studies have investigated the effects of different pretreatments on the performance of anaerobic digestion of sludge. However, the detailed changes of dissolved organic nitrogen, particularly the release behavior of proteins and the byproducts of protein hydrolysis-amino acids, are rarely known during anaerobic digestion of sludge by different pretreatments. Here we quantified the changes of three types of proteins and 17 types of amino acids in sludge samples solubilized by ultrasonic, thermal, and acid/alkaline pretreatments and their transformation during anaerobic digestion of sludge. Tryptophan protein, aromatic protein I, aromatic protein II, and cysteine were identified as the key dissolved organic nitrogen responsible for methane production during anaerobic digestion of sludge, regardless of the different pretreatment methods. Different from the depletion of other amino acids, cysteine was resistant to degradation after an incubation period of 30 days in all sludge samples. Meanwhile, the “cysteine and methionine metabolism (K00270)” was absent in all sludge samples by identifying 6755 Kyoto Encyclopedia of Genes and Genomes assignments of genes hits. Cysteine contributed to the generation of methane and the degradation of acetic, propionic, and n-butyric acids through decreasing oxidation-reduction potential and enhancing biomass activity. This study provided an alternative strategy to enhance anaerobic digestion of sludge through in situ production of cysteine.

Fenton and Fenton-like sludge conditioning processes have been studied intensively due to their superior efficiency in improving sludge dewaterability. But these processes inevitably produce a large quantity of Fe-rich sludge cake that induces challenges for disposal. Herein a sustainable sludge recycling strategy has been developed by using sludge-derived Fe-rich biochar as an iron source and catalyst to enhance sludge dewatering via advanced oxidation processes. Both homogeneous Fenton reactions initiated by the leached Fe2+ from the biochar, and heterogeneous Fenton reactions initiated by the bonded iron, in forms of Fe3O4, on the surface of the biochar, are revealed to contribute to the increase the amount of OH generation during sludge conditioning, which further improved the release of bound water and sludge dewaterability. The stability of the dewatering performance using the new strategy is demonstrated via three consecutive reuse cycles, in which a stable water contents of dewatered sludge cakes of approximately 46.38 wt% ± 2.88 is obtained. The iron content of the biochar becomes stable after the 2nd round recycle. A reduction of 28.39% on the total operating cost of sludge treatment could be realized when compared with the Fenton conditioning system without sludge recycling. The proposed sustainable sludge recycling strategy could realize zero disposal Fe-containing sludge, and meanwhile produce biochar that can be beneficially reused as valuable functional materials for other applications.

A facile, environmentally friendly and scalable method was reported to synthesize highly dispersed Bi-BiOCl nanoparticles dispersed on three dimensional porous networks of carbon nanosheet using NaCl as template and citric acid as carbon source. The novel 3D architecture demonstrated easily accessible porous structure, large surface area, superior electrical conductivity and good mechanical flexibility, which was capable of accelerating three dimensional diffusion of ions and transport of electrons in the whole electrode. In addition, the highly dispersed Bi-BiOCl nanoparticles on the carbon backbone could facilitate the utilization of these active materials in electrochemical sensing. Under optimized conditions, Bi-BiOCl@C-3 modified glassy carbon electrode exhibited preeminent electroanalytical performance for the simultaneous sensing of Pb2+ and Cd2+ in the linear range of 1–60 μg L−1, with sensitivities of 0.38 and 0.49 μA L μg−1, respectively. The developed protocol has shown limits of detection (S/N = 3) of 0.2 and 0.4 μg L−1 for Pb2+ and Cd2+, respectively, which complies with the limits set by the World Health Organization (WHO). Moreover, high resistance to interference, long-term stability, good reproducibility and satisfactory testing recoveries were realized for real water sample, suggesting that the proposed 3D Bi-BiOCl@C-3 nanocomposite could be utilized as a promising candidate for the fabrication of high-performance electrochemical sensor.

Wet chemical approach is widely applied for P extraction from incinerated sewage sludge ash (ISSA) due to the relatively simple process and low lost. In this study, H2SO4 and H2C2O4 were compared to recover P from ISSA through three steps of acid leaching, cation exchange resin (CER) purification and precipitation. Transformations of P speciation and mineral phases in ISSA from 600 to 900 °C were studied. The results showed that the ISSA samples were mainly composed of inorganic P (IP), and part of non-apatite IP (NAIP, mainly AlPO4) would transform to apatite P (AP, Ca3(PO4)2) with the increase in temperature. The ratio of NAIP to IP dropped from 71.9% at 600 °C to 53.7% at 900 °C. Effect of acid concentration on the leaching efficiency of P from the ISSA samples incinerated at different temperatures by H2SO4 and H2C2O4 was investigated, and the leaching behaviors of key elements of P, Ca, Al and Fe were compared. H2C2O4 exhibited a better performance than H2SO4 for the leaching efficiency of P. Severe sintering of ash particles occurred at temperature >800 °C inhibited the P leaching by H2SO4. During CER purification, the impurity elements in the H2SO4 leachate were easily removed by CER, whereas the Al and Fe elements in the H2C2O4 leachate were hardly removed due to the formation of anionic complexes between Al3+/Fe3+ and oxalic ions. Finally, high-purity struvite product was synthesized from the purified H2SO4 leachate, which could be directly utilized as a fertilizer with negligible environmental risk. Amorphous aluminum and iron hydroxyphosphates were obtained from the H2C2O4 leachate. This study provides insights for P recovery from ISSA samples by different acid leaching systems.

In this study, a method to reduce the emission of NOx precursors (e.g., hydrogen cyanide (HCN) and ammonia (NH3)) while simultaneously reclaim more plant-available P was proposed through pyrolyzing ferric sludge (sludge conditioned by Fenton's reagents) rather than raw sludge. The nitrogen and phosphorus transformation at different pyrolysis temperatures was investigated. The results indicated that in comparison with the pyrolysis of raw sludge, the remaining iron compounds in ferric sludge can fix char-N in more stable forms (e.g., appearance of pyrrole-N at 900 °C). The secondary cracking of amine-N compounds in tar-N (e.g., 81.67% increase of amine-N at 900 °C) can be inhibited. Hence, more amine-N was remained and less heterocyclic-N and nitrile-N compounds were generated in tar N. Less generation of NH3-N and HCN-N was also observed in NOx precursors (e.g., 5.46% decrease of NH3-N and 6.91% decrease of HCN-N at 900 °C). Moreover, the results of X-ray diffractometry, liquid 31P nuclear magnetic resonance spectroscopic, X-ray photoelectron spectroscopic, and chemical analyses collectively indicated that iron present in ferric sludge also favored reclamation of more plant-available P. In comparison with the pyrolysis of raw sludge, an increase in the total phosphorus pool was noted (18.06–36.26 versus 15.54–30.59 mg g−1 dry solids). A decrease in mobility with the predominant P as sodium hydroxide (NaOH)-P, and an increase in plant-available P can be also obtained. This study indicated that pyrolysis of ferric sludge was a feasible way to simultaneously reduce emission of NOx precursors, reclaim plant-available P, and reuse ferric sludge.

Pre-oxidation is effective in enhancing sludge dewaterability. Different types and doses of oxidants are used to improve sludge dewaterability in pre-oxidation. Rapid evaluation of the sludge dewaterability is vital for optimizing the type and dose of oxidants in pre-oxidation. It normally takes more time to evaluate sludge dewaterability by measuring typical indicators such as specific resistance to filtration (SRF), content of bound water, and composition of EPS. This study presented a rapid parameter, oxidation-reduction potential (ORP), to correlate it with the dewaterability of pre-oxidized sludge samples. An index of ΔORP (ΔORP = ORPt=0.5 min–ORPt=0 min) showed positive correlations with SRF (r = 0.89, p

A geopolymer material was synthesized from alkali-thermal pretreated Fe-rich Bayer red mud (RM) and fly ash. Dissolution efficiencies of Al2O3 and SiO2 in the RM in alkaline solutions were improved by pretreatment. The transformation of mineral phases in the RM during synthesis of geopolymer was investigated by the alkaline leaching test, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The role of Fe species in geopolymerization was investigated by Mossbauer spectra. The results showed that binding energies of Al-O and Si-O increased in geopolymerization; the coordinated Fe3+ replaced Al3+ in the aluminosilicate structure of geopolymer.