An electrospun three-layer nanofibrous membrane-based in situ gel separator for efficient lithium-organic batteries.

An in situ gel separator based on an electrospun three-layer nanofibrous membrane (PSE11-Gel) is developed for high-performance lithium-organic batteries (LOBs). The highly efficient shuttle effect inhibition of organic cathode molecules or lithiated intermediates has been demonstrated for PSE11-Gel to realize high-capacity stable LOBs.

Interface engineering of Mn3O4/Co3O4 S-scheme heterojunctions to enhance the photothermal catalytic degradation of toluene.

Transition metal oxides have high photothermal conversion capacity and excellent thermal catalytic activity, and their photothermal catalytic ability can be further improved by reasonably inducing the photoelectric effect of semiconductors. Herein, Mn3O4/Co3O4 composites with S-scheme heterojunctions were fabricated for photothermal catalytic degradation of toluene under ultraviolet-visible (UV-Vis) light irradiation. The distinct hetero-interface of Mn3O4/Co3O4 effectively increases the specific surface area and promotes the formation of oxygen vacancies, thus facilitating the generation of reactive oxygen species and migration of surface lattice oxygen. Theoretical calculations and photoelectrochemical characterization demonstrate the existence of a built-in electric field and energy band bending at the interface of Mn3O4/Co3O4, which optimizes the photogenerated carriers' transfer path and retains a higher redox potential. Under UV-Vis light irradiation, the rapid transfer of electrons between interfaces promotes the generation of more reactive radicals, and the Mn3O4/Co3O4 shows a substantial improvement in the removal efficiency of toluene (74.7%) compared to single metal oxides (53.3% and 47.5%). Moreover, the possible photothermal catalytic reaction pathways of toluene over Mn3O4/Co3O4 were also investigated by in situ DRIFTS. The present work offers valuable guidance toward the design and fabrication of efficient narrow-band semiconductor heterojunction photothermal catalysts and provides deeper insights into the mechanism of photothermal catalytic degradation of toluene.

Tunning active oxygen species for boosting Hg0 removal and SO2-resistance of Mn-Fe oxides supported on (NH4)2S2O8 doping activated coke.

Active oxygen species (AOS) play an essential role in modulating the activity of activated coke (AC) based samples. In this paper, AC was endowed with abundant AOS by modifying with (NH4)2S2O8 and MnOx-FeOx for Hg0 removal. (NH4)2S2O8 treatment induced abundant micropores and oxygen-containing functional groups, and thus provided more anchoring sites for the dispersion of MnOx-FeOx. The synergy of MnOx-FeOx and interaction between MnOx-FeOx and NAC support contributed to a larger surface area, highly-dispersed active components, stronger reducibility, and more metal ions with high valence of MnFe/NAC. The optimal MnFe/NAC exhibited superior Hg0 removal efficiency above 90% at 120∼180 â„ƒ, as well as excellent performance for simultaneous removal of Hg0 and NO, and 600 ppm SO2 and 8 vol.% H2O addition led to a slight deterioration. XPS and Hg-TPD revealed that mercury adsorbed on MnFe/NAC included phy-Hg, C=O-Hg, COO-Hg, and OL-HgO. Besides, the priority of AOS for Hg0 chemisorption was C=O > COO- > OL, and Hg2+ was also detected in the outlet. Moreover, the SO2-poisoning effect was ascribed to the sulfation of MnOx and the occupation of COO- and C=O, and FeOx incorporation enhanced the SO2-resistance through weakening SO2 adsorption on C=O and COO-. The motivation of O2 mainly contributed to the regeneration of AOS, especially OL. The excellent regeneration performance and stability further affirmed the application potential of MnFe/NAC for Hg0 capture from coal-fired flue gas.

Recent Progress of Carbon Dots for Air Pollutants Detection and Photocatalytic Removal: Synthesis, Modifications, and Applications.

Rapid industrialization has inevitably led to serious air pollution problems, thus it is urgent to develop detection and treatment technologies for qualitative and quantitative analysis and efficient removal of harmful pollutants. Notably, the employment of functional nanomaterials, in sensing and photocatalytic technologies, is promising to achieve efficient in situ detection and removal of gaseous pollutants. Among them, carbon dots (CDs) have shown significant potential due to their superior properties, such as controllable structures, easy surface modification, adjustable energy band, and excellent electron-transfer capacities. Moreover, their environmentally friendly preparation and efficient capture of solar energy provide a green option for sustainably addressing environmental problems. Here, recent advances in the rational design of CDs-based sensors and photocatalysts are highlighted. An overview of their applications in air pollutants detection and photocatalytic removal is presented, especially the diverse sensing and photocatalytic mechanisms of CDs are discussed. Finally, the challenges and perspectives are also provided, emphasizing the importance of synthetic mechanism investigation and rational design of structures.

Exosomes from human induced pluripotent stem cells derived mesenchymal stem cells improved myocardial injury caused by severe acute pancreatitis through activating Akt/Nrf2/HO-1 axis.

Human induced pluripotent stem cell-derived mesenchymal stem cells (iMSCs) have been believed to be a promising alternative for the stem cell transplantation therapy. The exosomes (Exo) from iMSCs play an important role in several kinds of life activities. The role of exosomes from iMSCs in severe acute pancreatitis (SAP) induced myocardial injury (MI) has not been investigated. The Exo were isolated from iMSCs through differential centrifugation method. The SAP rat model was established with 5% sodium taurocholate injection into the distal end of the bilepancreatic duct. RT-PCR and western blotting were used to measure related gene expression. Masson trichrome and Sirius Red stainings were used to evaluate MI injury. Cardiac function was detected through cardiac ultrasound.Exo promoted cell viability through activating Akt/nuclear factor E2 related factors 2 (Nrf2)/heme oxygenase 1 (HO-1) signaling pathway in vitro. Exo improved MI induced by SAP through activating Akt/Nrf2/HO-1 signaling pathway. Exo improved cardiac function, and suppressed oxidative status in the SAP model. Exo increased the expression of von Willebrand Factor (vWF) and vascular endothelial growth factor (VEGF) through activating Nrf2/HO-1 signaling pathway. Our data indicated that the Exo from iMSCs could improve MI caused by SAP through activating Nrf2/HO-1 axis. These findings firstly unfold the potential application of Exo from iMSCs in treating MI induced by SAP.Abbreviations: LVEF: Left ventricular ejection fraction; LVFS: left ventricular fractional shorten; LVDd: left ventricular end-diastolic diameter; LVDs: left ventricular end-systolic diameter; MI: Myocardial infarction; MSCs: Mesenchymal stem cells; iPSCs: Human-induced pluripotent stem cells; SAP: Severe acute pancreatitis; iMSCs: iPSCs derived VEGF: MSCs; vascular endothelial growth factor; Nrf2: Nuclear factor erythroid 2-related factor; RT-PCR: Real-time polymerase chain reaction; HE: Hematoxylin-eosin; MODS: Multiple organ dysfunction syndrome; PI3K: Phosphatidylinositol 3-kinase; SOD: Superoxide dismutase; FBS: Fetal bovine serum; ECL: Enhanced chemiluminescence; IHC: Immunohistochemistry.

LaOx modified MnOx loaded biomass activated carbon and its enhanced performance for simultaneous abatement of NO and Hg0.

A battery of agricultural straw derived biomass activated carbons supported LaOx modified MnOx (LaMn/BACs) was prepared by a facile impregnation method and then tested for simultaneous abatement of NO and Hg0. 15%LaMn/BAC manifested excellent removal efficiency of Hg0 (100%) and NO (86.7%) at 180 °C, which also exhibited splendid resistance to SO2 and H2O. The interaction between Hg0 removal and NO removal was explored; thereinto, Hg0 removal had no influence on NO removal, while NO removal preponderated over Hg0 removal. The inhibitory effect of NH3 was greater than the accelerative effect of NO and O2 on Hg0 removal. The physicochemical characterization of related samples was characterized by SEM, XRD, BET, H2-TPR, NH3-TPD, and XPS. After incorporating suitable LaOx into 15%Mn/BAC, the synergistic effect between LaOx and MnOx contributed to the improvement of BET surface area and total pore volume, the promotion of redox ability, surface active oxygen species, and acid sites, inhibiting the crystallization of MnOx. 15%LaMn/BAC has the best catalytic oxidation activity at low temperature. That might be answerable for superior performance and preferable tolerance to SO2 and H2O. The results indicated that 15%LaMn/BAC was a promising catalyst for simultaneous abatement of Hg0 and NO at low temperature.

Thermal treatment of sewage sludge: A comparative review of the conversion principle, recovery methods and bioavailability-predicting of phosphorus.

Phosphorus is a nutrient that is essential to nature and human life and has attracted attention because of its very limited reserves. Dwindling phosphorus reserves and soaring prices have made the recovery of phosphorus from waste biosolids even more urgent. Waste activated sludge, as the final destination of most of the phosphorus in human domestic and industrial water, has been considered as a reliable source of phosphorus recovery. The thermal treatment method of sewage sludge is currently a relatively environmentally friendly disposal method, which mainly includes incineration, pyrolysis and hydrothermal carbonization. This paper reviews the methods for the recovery of different forms of phosphorus (wet chemical, thermochemical and electrodialysis) from solid products obtained from different sludge thermal treatment methods (incinerated sewage sludge ash, pyrolysis of sewage sludge char and hydrochar) and the bioavailability of the recovered phosphorus products. Incineration of sewage sludge is currently the most established and effective method for recovering phosphorus from the thermal treatment products of sewage sludge. One of the wet chemical methods has been applied on a commercial scale and is expected to be further developed for future industrial applications. Pyrolysis and hydrothermal carbonation still have many research gaps in this field. Based on their principles and laboratory performance, both of them have the potential to recover phosphorus and should be further explored.

Improvement of cardiac function by mesenchymal stem cells derived extracellular vesicles through targeting miR-497/Smad7 axis.

BACKGROUND: The extracellular vesicles (EVs) secreted by bone marrow mesenchymal stromal cells (MSCs) have the ability to improve Myocardial infarction (MI). Some microRNAs (miRNAs) including miR-497 and related target genes have been proved to be closely linked with heart diseases. However, EVs could regulate MI process through miR-497, and the mechanisms have not been fully reported. METHODS: Ligation of left anterior descending artery was performed to established MI animals model. Hypoxia cell model was established through lowering the level of oxygen. The cell invasion, migration, and proliferation were measured using tanswell, wound heating, and MTT assays. HE, Masson trichrome, and Sirius Red staining were used to investigate the morphological changes. RESULTS: Overexpression of miR-497 reversed the promotion of cell migration, invasion, and proliferation caused by EVs. The improvement of cardiac function induced by EVs could also be reversed by overexpression of miR-497. Direct binding site between Smad7 and miR-497 was identified. Knockdown of Smad7 reversed the improvement of cardiac function induced by EVs. CONCLUSIONS: We found that EVs isolated from MSCs might improve the cardiac injury caused by MI through targeting miR497/Smad7. This study provides novel potential therapeutic thought for the prevention and treatment of MI through targeting miR-497/Smad7.

Catalytic enhancement of hydrogenation reduction and oxygen transfer reaction for perchlorate removal: A review.

Perchlorate is the main contaminant in surface water and groundwater, and it is of current urgency to remove due to its high water solubility, mobility, and endocrine-disrupting properties. The conversion of perchlorate into harmless chloride ions by using appropriate catalysts is the most promising and effective route to overcome its high activation energy and kinetic stability. Perchlorate is usually reduced in two ways: (1) indirect reduction via oxygen atom transfer (OAT) reaction or (2) hydrodeoxygenation through highly active reducing H atoms. This paper discusses the mechanisms underlying both the OAT reaction catalyzed by homogenous rhenium-oxo complexes or biological Mo-based enzymes and the heterogeneous hydrogenation for perchlorate reduction. Particular emphasis is placed on the factors affecting the catalytic process and the synergy between the (1) and (2) reactions. For completeness, the applicability of different electrolysis devices, electrodes, and bioreactors is also illustrated. Finally, this article gives prospects for the synthesis and application of catalysts in different pathways.

[Clinical study on intravenous combined with aerosol inhalation of polymyxin B for the treatment of pneumonia caused by multidrug-resistant Gram-negative bacteria].

OBJECTIVE: To investigate the efficacy of intravenous combined with aerosol inhalation of polymyxin B for the treatment of pneumonia caused by multidrug-resistant Gram-negative (G-) bacteria. METHODS: A observational study was conducted. The clinical data of 45 patients with pneumonia due to multidrug-resistant G- bacteria admitted to intensive care unit of Fujian Medical University Union Hospital from January to October in 2020 were analyzed. According to the different use methods of polymyxin B, 25 patients who received single intravenous drip (the first dose was 2.0 mg/kg, then 1.25 mg/kg, once every 12 hours) from January to April in 2020 were enrolled in the routine group, and 20 patients who received intravenous drip combined with aerosol inhalation (25 mg once every 12 hours, sputum in the airway was sucked and then sprayed aerosol) from May to October in 2020 were enrolled in the combination group. After the treatment course of polymyxin B, the total bacterial clearance rate, total clinical efficiency rate, recovery time of body temperature, time of bacterial clearance and the change of serum procalcitonin (PCT) level before and after treatment were compared between the two groups. Moreover, the incidence of adverse reactions during treatment in the two groups was observed. RESULTS: The results of sputum culture in the routine group were Acinetobacter baumannii in 13 patients, Klebsiella pneumoniae in 5 patients, Pseudomonas aeruginosa in 6 patients, Enterobacter cloacae in 1 patient; the sputum culture results of the combination group showed that there were 5 patients of Acinetobacter baumannii, 9 Klebsiella pneumoniae and 6 Pseudomonas aeruginosa. There was no significant difference in the results of sputum culture between the two groups (P > 0.05). The total bacterial clearance rate and the total clinical efficiency rate of the combination group were significantly higher than those in the routine group (total bacterial clearance rate: 70.0% vs. 40.0%, total clinical efficiency rate: 75.0% vs. 40.0%, both P < 0.05). The recovery time of body temperature and the time of bacterial clearance of the combination group were significantly shorter than those in the routine group [recovery time of body temperature (days): 6.0±3.9 vs. 10.2±7.3, time of bacterial clearance (days): 6.1±5.2 vs. 11.5±6.8, both P < 0.05]. No significant difference was found in serum PCT level before treatment between the two group. There was no significant difference in serum PCT level before and after treatment in the routine group [µg/L: 0.85 (0.44, 2.87) vs. 1.43 (0.76, 5.30), P > 0.05]. The serum PCT level after treatment in the combination group was significantly lower than that before treatment [µg/L: 0.27 (0.10, 0.70) vs. 0.91 (0.32, 3.53), P < 0.05], and it was significantly lower than that in the routine group [µg/L: 0.27 (0.10, 0.70) vs. 0.85 (0.44, 2.87), P < 0.01]. The incidence of renal toxicity of polymyxin B between the combination group and the routine group was not significantly different (5.0% vs. 4.0%, P > 0.05). CONCLUSIONS: The efficacy of intravenous combined with aerosol inhalation of polymyxin B for the treatment of pneumonia due to multidrug-resistant G- bacteria is better than that of intravenous drip of polymyxin B only. The aerosolized polymyxin B will not increase the risk of renal injury.

Highly efficient simultaneous removal of HCHO and elemental mercury over Mn-Co oxides promoted Zr-AC samples.

MnxCoy/Zrz-AC prepared by impregnation method was investigated on the simultaneous removal of HCHO and Hg0. The samples were characterized by BET, SEM, XRD, H2 pulse chemisorption, H2-TPR, XPS, Hg-TPD and in-situ DRIFTS. Thereinto, the optimal Mn2/3Co8/Zr10-AC achieved 99.87% HCHO removal efficiency and 82.41% Hg0 removal efficiency at 240 °C, respectively. With increased surface area and pore volume, Zr-AC support facilitated higher dispersion of MnOx-CoOx. Moreover, the co-doping of MnOx-CoOx endowed the sample with more active oxygen species and higher reducibility, which further facilitated the removal of HCHO and Hg0. Chemisorption was proved to predominate in Hg0 removal, and oxidation also worked as Hg2+ was detected in outlet gas. Besides, HCHO predominated in the competition of active oxygen species, especially for lattice oxygen, thus suppressed the Hg0 removal. According to in-situ DRIFTS, HCHO removal proceeded as HCHOads → DOM → formate species → CO2 + H2O, and was boosted by active oxygen species. Furthermore, Mn2/3Co8/Zr10-AC was proved with excellent regeneration performance, indicating its potential in practical application.

Insight into the effect of SO2 on the Hg0 removal performance over a 1V-8Ce/AC sorbent at low temperatures.

The influences of SO2 on Hg° removal over the 1V-8Ce/AC sorbent were systematically investigated at low temperatures. The experimental results showed that SO2 has a dual effect on Hg° removal, that is, SO2 has both a promoting effect and an inhibiting effect on Hg° removal. The SO2 transient response experiment indicated that SO2 could not only react with Hg° to promote the removal of Hg° but also react with the active components and poison the sorbent. O2 is indispensable for the removal of Hg°, which can offset the adverse effects caused by SO2 and H2O. HCl exhibited an obvious promoting effect on Hg° removal in the presence of SO2. The 1V-8Ce/AC sorbent exhibited good sulfur resistance and excellent stability (EHg = 90.04 %) after a 24 h reaction performed under the 1000 ppm SO2 condition at 150 °C. In addition, the Hg-TPD and XPS methods were used to assist in studying the effect of SO2 on Hg° removal over the 1V-8Ce/AC sorbent. Finally, the mechanism of Hg° removal in an SO2 atmosphere was also explored, which showed that Hg° was removed by two possible pathways over the 1V-8Ce/AC sorbent.

Electrochemical Synthesis and Electro-Optical Properties of Dibenzothiophene/Thiophene Conjugated Polymers With Stepwise Enhanced Conjugation Lengths.

A total of six conjugated polymers, namely PDBT-Th, PDBT-Th:Th, PDBT-2Th, PDBT-Th:2Th, PDBT-2Th:Th, and PDBT-2Th:2Th, consisting of dibenzothiophene, thiophene, and bithiophene were electrochemically synthesized. Their electrochemical and electrochromic properties were investigated in relation to the conjugation chain lengths of the thiophene units in the conjugated backbones. Density functional theory (DFT) calculations showed that longer conjugation lengths resulted in decreased HOMO-LUMO gaps in the polymers. The optical band gaps (E g,opt) and electrochemical band gaps (E g,cv) were decreased from PDBT-Th to PDBT-Th:Th, however, PDBT-Th:2Th, PDBT-2Th, PDBT-2Th:Th and PDBT-2Th:2Th displayed the similar band gaps. The conjugation length increments significantly improved the electrochemical stability of the conjugated polymers and exhibited reversible color changes due to the formation of polarons and bipolarons. The results suggest that the conjugated polymers prepared herein are promising candidates for fabricating flexible organic electrochromic devices.

Catalytic co-pyrolysis of sewage sludge and rice husk over biochar catalyst: Bio-oil upgrading and catalytic mechanism.

In this study, the effects of different biochar catalysts on the quality of bio-oil derived from the co-pyrolysis of sewage sludge (SS) and rice husk (RH) are explored. Catalysts include SS biochar (SWC), RH biochar (RHC), mixed SS and RH biochar (SRC), and RH ash (RHA). The quality of bio-oil was evaluated based on the results of gas chromatography-mass spectrometry (GC-MS; including the contents of hydrocarbons and N-species), oxygen content, higher heating value, and pH. The GC-MS analysis results illustrated that N-species content in the bio-oil reduced with the addition of the biochar catalyst, while the hydrocarbons content increased from 15.51% for co-pyrolysis to 38.74-61.84% for different biochar catalysts at a catalytic temperature of 650 °C. RHC exhibited the best catalytic effect in terms of decreasing the content of N-species by 58.79% and increasing the content of hydrocarbons by nearly four times compared to co-pyrolysis. The higher heating value of bio-oil raised from 25.75 to 34.67 MJ/kg, while oxygen content decreased from 31.1 to 8.81 wt%, and the pH increased from 4.06 to 5.48. Moreover, the catalytic mechanism of catalytic co-pyrolysis over RHC, including the hydrocarbon generation pathway and nitrogen removal, is also discussed here. High specific surface area of RHC provides sufficient active sites (e.g. O-containing and N-containing functional groups) for the catalytic reaction of pyrolytic intermediates.

Ultrafine Re/Pd nanoparticles on polydopamine modified carbon nanotubes for efficient perchlorate reduction and reusability.

This study synthesized nanocomposite catalysts via a modification of Re/Pd codoped carbon nanotubes (CNTs) with different concentrations of polydopamine (PDA), which were used for perchlorate (ClO4-) reduction. The loads, dispersion and reducibility of Re/Pd nanoparticles increased yet their particle sizes significantly decreased with the increase of PDA concentrations. The average diameter of Re/Pd codoped D2CNT (CNT modified by 2 mg/mL PDA) with a narrow size distribution was measured to be 2 nm. The ultrafine Re/Pd codoped D2CNT catalysts represented outstanding catalytic reduction activity for the conversion of ClO4- to Cl- with TOF of 17.34 h-1 under the room H2 atmospheric pressure, which was about 8 times than that of the unmodified catalysts. Furthermore, PDA modification minimized the dissociation of Re by chemical bonding between Re and CNTs carrier and maintained good stability of nanocomposite. This study inspires us to apply green bionic methods to enhance the catalytic reduction of perchlorate by changing the physical properties of Re/Pd nanoparticles.

Promotional removal of gas-phase Hg0 over activated coke modified by CuCl2.

Impregnating CuCl2 on AC (activated coke) support to synthesize xCuCl2/AC showed superior activity with higher 90% Hg0 removal efficiency at 80-140 °C, as well as a lower oxygen demand of 2% O2 for Hg0 removal. The acceleration on Hg0 removal was observed for NO and SO2. The BET, SEM, XRD, XPS, TPD, and FT-IR characterizations revealed that the larger surface area, sufficient active oxygen species and co-existence of Cu+ and Cu2+ may account for the efficient Hg0 removal. In addition, the low demand of gaseous O2 was contributed to higher content of active oxygen and formed active Cl. After adsorbing on Cu sites, Cl sites, and surface functional groups, the Hg0(ads) removal on xCuCl2/AC was proceeded through two ways. Part of Hg0(ads) was oxidized by active O and formed Hg0, and the other part of Hg0 combined with the active Cl, which was formed by the activation of lattice Cl with the aid of active O, and formed HgCl2. Besides, the Hg2+ detected in outlet gas through mercury speciation conversion and desorption peak of HgCl2 and Hg0 further proved it. As displayed in stability test and simulated industrial application test, CuCl2/AC has a promising industrial application prospect.

Effect of temperature on the sulfur fate during hydrothermal carbonization of sewage sludge.

To understand the effect of reaction temperature on sulfur during hydrothermal carbonization (HTC) of sewage sludge (SS), seven group of temperature (180-300 °C) were chosen to investigate the distributions and evolution of sulfur-containing compounds in hydrochar and the liquid products. Elemental analysis, X-ray photoelectron spectroscopy (XPS), and X-Ray powder diffraction (XRD) were used to characterize the distribution of sulfur in hydrochar. The concentrations of sulfate ions and sulfide were determined in the liquid sample. The experimental results showed that as the temperature increased, the O/C ratio decreased because of the improved carbonization degree of SS. After hydrothermal carbonization, 90% of the sulfur in SS remained in hydrochar. As the temperature increased, the amount of sulfur in the liquid, mainly in the form of sulfate ions, tended to decrease. However, the experimental results for the gas phase were the opposite of the liquid phase.

Hydrothermal carbonization of sewage sludge: Effect of feed-water pH on hydrochar's physicochemical properties, organic component and thermal behavior.

In this study, hydrothermal carbonization (HTC) of sewage sludge(SS) was carried out at a temperature of 270℃ and a resulting pressure of 7-9 MPa with 2 h. The effect of feed water pH values in the range of 2-12 on hydrochar characteristics, organic component and thermal behavior was evaluated. The result shows that with the pH value increasing, ash content shows a trend of decline, and organic components in the hydrochar become significantly simpler than SS. hydrochar is more beneficial to produce a fatty substance during an acidic environment and alkaline environments favor the formation of N-containing organic compounds and ketone organics, especially in strongly alkaline environments. Compared to the SS, hydrochar burning interval shortened 100℃ and the combustion of hydrochar is more durable. Considering the organic composition and combustion performance of hydrochar, it is found that the hydrochar prepared under 270-5 condition has the best effect.

Fe(II) activated persulfate assisted hydrothermal conversion of sewage sludge: Focusing on nitrogen transformation mechanism and removal effectiveness.

In this study, Fe(II)-activated persulfate-assisted hydrothermal treatment (Fe(II)-PS-HT) was used to improve the efficiency of removing nitrogen (N) from the sewage sludge (SS) under relatively mild conditions (i.e., at 150 °C, for 20min), and the N transformation mechanism was investigated. The total N content in the solid residue was used to evaluate the N removal efficiency. Further, the redistribution of N in the solid and liquid products was characterized and quantified to obtain a N transformation mechanism during sequential persulfate oxidation (Fe(II) and persulfate) assisted hydrothermal treatment (HT). The experimental results denote that the N removal efficiency obtained from the Fe(II)-PS-HT (persulfate/C = 0.085 and Fe(II)/persulfate = 0.5) treated SS was increased by 35.0% at a relatively mild temperature (i.e., 150 °C) when compared with that obtained by treating SS using normal HT. Elevating Fe(II)/persulfate ratio to 1.25 promoting the N removal efficiency by 59.9%-65.9%. Furthermore, the electron paramagnetic resonance (EPR) and scanning electron microscopy (SEM) results clearly denote a N removal mechanism where the sulfate radicals (SO4∙-) produced by Fe(II)-PS destroy the sludge structure and destructed extracellular polymers (EPS). In the absence of EPS protection, proteins were directly exposed to extreme hydrothermal circumstances, and were rapidly transformed from the SS into the liquid residue. The free radicals also provided energy for the denitrification of Heterocycle-N. Consequently, a high N removal efficiency was obtained by Fe(II)-PS-HT with persulfate/C = 0.085 and Fe(II)/persulfate = 1.25 at 150 °C for 20 min.

In-depth comparison of morphology, microstructure, and pathway of char derived from sewage sludge and relevant model compounds.

Hydrothermal conversion (HTC) of sewage sludge (SS) and its relevant model compounds such as cellulose, glucose, lignin and soybean protein (substitute for protein) was experimentally conducted at moderate reaction temperature of 260 °C for 60 min. The structural properties, carbon-containing groups, and microstructure of the char were characterised by several techniques. The results revealed that more benzene rings were formed by small clusters and the CO bond on Aryl-alkyl ether decomposed on the surface particles during the HTC process. In addition, the catalyst Zeolite Socony Mobil-5 (ZSM-5, Si/Al: 300) showed an excellent performance on the high graphite degree of the char under moderate reaction temperature of 260 °C. In particular, cellulose has the most dramatic influence on the depolymerisation of C(C,H). As evidenced with SEM, the size of the char derived from SS with ZSM-5 catalyst is 10-15 µm, which is smaller than the char without catalyst. A mechanism for derivation of char from individual model compounds is proposed. The end products of lignin are composed of polyaromatic char, while the composition of the char derived from protein suggests that polymerisation may occur during hydrothermal reaction leading to formation of structures with N-containing compounds.