Low-cost pyrolysis of biomass-derived nitrogen-doped porous carbon: Chlorella vulgaris replaces melamine as a nitrogen source.

Porous carbon generated from biomass has a rich pore structure, is inexpensive, and has a lot of promise for use as a carbon material for energy storage devices. In this work, nitrogen-doped porous carbon was prepared by co-pyrolysis using bagasse as the precursor and chlorella as the nitrogen source. ZnCl2 acts as both an activator and a nitrogen fixer during activation to generate pores and reduce nitrogen loss. The thermal weight loss experiments showed that the pyrolysis temperatures of bagasse and chlorella overlap, which created the possibility for the synthesis of nitrogen-rich biochar. The optimum sample (ZBC@C-5) possessed a surface area of 1508 m2g-1 with abundant nitrogen-containing functional groups. ZBC@C-5 in the three-electrode system exhibited 244.1F/g at 0.5A/g, which was extremely close to ZBC@M made with melamine as the nitrogen source. This provides new opportunities for the use of low-cost nitrogen sources. Furthermore, the devices exhibit better voltage retention (39%) and capacitance retention (96.3%). The goal of this research is to find a low cost, and effective method for creating nitrogen-doped porous carbon materials with better electrochemical performance for highly valuable applications using bagasse and chlorella.

Effect of microwave pretreatment on pyrolysis of chili straw: thermodynamics, activation energy, and solid reaction mechanism.

In this work, chili straw (CS) was pretreated by microwave at 250 W, 406 W, 567 W, and 700 W. The pyrolysis characteristics, kinetics, thermodynamic parameters, and solid reaction mechanism were investigated. The maximum weight loss rate increases from - 24.72%/°C at P0 to - 28.01%/°C at P700 after microwave pretreatment, and the residual mass decreases from 31.81 at P0 to 26.71% at P700. In addition, microwave pretreatment leads to a decrease in activation energy, ∆H, and ∆G at the end of the pyrolysis (α > 0.7). The solid reaction mechanism of CS pyrolysis is revealed by the Z-master plots method, with un-pretreated CS conforming to P2, D4, F3/2, and F3, respectively. Microwave pretreatment changes the solid reaction mechanism mainly in the third stage, when α = 0.8, the mechanism function changes from f(α) = (1 - α)3 at P0 to f(α) = (1 - α) at P700, and the number of reaction order is reduced, which is profitable for CS pyrolysis.

Preparation of high-value porous carbon by microwave treatment of chili straw pyrolysis residue.

Microwave technology is utilized to prepare porous carbon from the chili straw pyrolysis residue in this study. As the pyrolysis temperature increases, the thermal stability of biochar is higher. The carbon speciation of the porous carbon PC500 is closest to that of graphite, and its inorganic-C reaches to 51.21%. Notably, the specific surface area of the activated porous carbon increases with increasing pyrolysis temperature, with a maximum value of 2768.52 m2/g for PC500. Further testing of the electrochemical properties of the porous carbon, PC500 possesses a high specific capacitance of 352F/g at 1 A/g while that of conventional heating is only 226.1F/g. The porous carbon prepared by microwave heating has better electrical properties compared to conventional heating, and the biochar obtained at higher pyrolysis temperature has a richer pore structure after activation.

CXCR4 blockade in macrophage promotes angiogenesis in ischemic hindlimb by modulating autophagy.

Chemokine receptor CXCR4 plays a crucial role in leukocyte recruitment and inflammation regulation to influence tissue repair in ischemic diseases. Here we assessed the effect of CXCR4 expression in macrophages on angiogenesis in the ischemic hindlimb of a mouse. Inflammatory cells were increased in the ischemic muscles of hindlimb, and CXCR4 was highly expressed in the infiltrated macrophages but not in neutrophils. Myeloid-specific CXCR4 knockout attenuated macrophage infiltration and subsequent reduced inflammatory response in the ischemic hindlimb, accompanied with better blood reperfusion and higher capillary density as compared with that in LysM Cre+/- (Cre) mice. Similar outcomes were also observed in CRE mice whose bone marrow cells were replaced with those from CXCR4-deficient mice. Gene ontology cluster analysis reviewed that Decorin, a negative regulator of angiogenesis, was reduced in CXCR4-deficient macrophages. CXCR4-deficient macrophages were less inducible into M1 phase by lipopolysaccharide and more favorable for M2 polarization under oxygen/glucose deprivation condition. Enhanced autophagy was detected in CXCR4-deficient macrophages, which was associated with less expression of both Decorin and the inflammatory cytokines. In summary, myeloid-specific CXCR4 deficiency reduced monocyte infiltration and the secretion of inflammatory cytokines and Decorin from macrophages, thus blunting inflammation response and promoting angiogenesis in the ischemic hindlimb.

CXCR4-dependent macrophage-to-fibroblast signaling contributes to cardiac diastolic dysfunction in heart failure with preserved ejection fraction.

Rationale: Heart failure with preserved ejection fraction (HFpEF) can arise from hypertension-induced cardiac remodeling. Monocyte/macrophage accumulation and inflammation are crucial elements in the pathogenesis of hypertension-induced cardiac remodeling. The C-X-C chemokine receptor 4 (CXCR4) is a critical regulator of the macrophage-mediated immune response. Nevertheless, the contribution of CXCR4 to macrophage phenotype and function during the progression of HFpEF remains unclear. Herein, we aimed to determine the role of macrophagic CXCR4 in heart failure with preserved ejection fraction (HFpEF). Methods: As a HFpEF model, wild type mice and myeloid-specific CXCR4 deficiency mice were subjected to pressure overload for 30 days to assess the function of macrophagic CXCR4 on cardiac function. Medium from macrophages was used to treat cardiac fibroblasts to study macrophage-to-fibroblast signaling. Results: We found circulatory CXCR4+ immune cells, mainly monocytes, markedly increased in HFpEF patients with hypertension. In the experimental HFpEF mice model, macrophages but not neutrophils represent the main infiltrating inflammatory cells in the heart, abundantly expressing CXCR4. Myeloid-specific CXCR4 deficient impeded macrophage infiltration and inflammatory response in the heart of HFpEF mice, thus ameliorating cardiac fibrosis and improving cardiac diastolic function. Furthermore, transcriptomic profiling data revealed that CXCR4 loss in macrophages exhibited a decreased transcriptional signature associated with the regulation of inflammatory response. Notably, CXCR4 significantly augmented chemokine (C­X­C) motif ligand (CXCL3) expression, which at least partly contributed to fibrosis by promoting myofibroblast differentiation. Mechanistically, the increased production of pro-inflammatory cytokines in CXCR4 expressed macrophages could be attributed to the suppression of the peroxisome proliferator-activated receptor γ (PPARγ) activity. Conclusions: Collectively, our data supported that the infiltration of CXCR4+ macrophages in the heart exacerbates hypertension-induced diastolic function by promoting pro-inflammatory cytokines production and thus may serve as a potential therapeutic target for hypertension-induced HFpEF.

Size effect of γ-MnO2 precoated anode on lead-containing pollutant reduction and its controllable fabrication in industrial-scale for zinc electrowinning.

Lead (Pb) is the most widely used anode in zinc (Zn) electrowinning and other metallurgical industries. The resource loss and environmental pollution caused by Pb anode corrosion are urgent problems to be solved. A γ-MnO2 precoated anode was prepared successfully to reduce the Pb-containing pollutant. The size effects with its controllable preparation on an industrial scale were studied. Severe nonuniform distribution of γ-MnO2 film was observed with curbing the reduction of anode slime only 68%, when anode size increased from lab to industry. Nonuniform rate (R) and average thickness (d) were found to be the key indicators to determine the film structure distribution and their performance differences, which were random and difficult to be controlled in scale-up size. However, a controllable industrial γ-MnO2 precoated anodes (IMPA) fabricated through optimized current density (J0) and electrodeposition time (t) in our developed film-forming system. Then, the long-term performances of two IMPA with different indicators (IMPA-1: R = 34%, d = 108 µm, IMPA-2: R = 23%, d = 55 µm) were compared with the industrial typical Pb-based anode (ITPA). Of the three different anodes, the optimized IMPA-2 displayed the best performance. Within 24 d of electrowinning cycle, the corrosion inhibition effect and the anode slime reduction rate for IMPA-2 improved by 56% and 30% than IMPA-1, and improved by 100% and 91% than ITPA. Furthermore, the mechanism analysis of size effect change showed that R of IMPA was contributed to the local gas holdup distribution along the anode. Controlled size effect of uniform oxide film will have a future application prospect for the sustainability of industry, which provides an important cleaner production of Zn electrowinning and related hydrometallurgy industries.

Catalytic co-pyrolysis of microwave pretreated chili straw and polypropylene to produce hydrocarbons-rich bio-oil.

In this work, the kinetic behavior and products of the co-pyrolysis of chili straw (CS) and polypropylene (PP) of distinguishing conditions (blending ratios, addition of catalysts, and microwave pretreatment at different power) had been investigated. Co-pyrolysis effectively reduced the proportion of oxygenated composition in CS, and the Oxygenated composition of 5CS5PP decreased by 76.69% compared to CS. When HZSM-5 was added, the aromatic hydrocarbons in the product increased from 4.46% to 17.34%, and the final residual mass decreased from 12.75% to 7.71%, illustrating that HZSM-5 had a positive effect on co-pyrolysis. Compared with P0HZSM-5, the microwave pretreatment at a higher power level of 567 W reduced the oxygenated composition from 17.41% to 13.09%, and the weight loss peak in the first stage increased from -18.11%/min to -19.94%/min. At the same time, the activation energy decreased from 271.25 kJ/mol to 231.13 kJ/mol.

Comparison of catalytic effect on upgrading bio-oil derived from co-pyrolysis of water hyacinth and scrap tire over multilamellar MFI nanosheets and HZSM-5.

Catalytic co-pyrolysis of water hyacinth and scrap tire experiments were performed to evaluate the feasibility of improving the monocyclic aromatic hydrocarbons production. The production of monocyclic aromatic hydrocarbons increased from 5.31% (sole pyrolysis of water hyacinth) to 13.11% (co-pyrolysis with scrap tire). With use of zeolites, the highest production of monocyclic aromatic hydrocarbons can reach up to 69.18%. Comprehensive comparison on catalytic effects of HZSM-5 and multilamellar MFI nanosheets were provided. With the material to multilamellar MFI nanosheets ratios changes from 2:1 to 1:4, the production of monocyclic aromatic hydrocarbons increases significantly from 37.15-69.18%. The average production of monocyclic aromatic hydrocarbons produced by using multilamellar MFI nanosheets were 12.07% higher than that using HZSM-5, indicating the better performance of multilamellar MFI nanosheets in producing monocyclic aromatic hydrocarbons. This work provided a reference for the reuse of water hyacinth and scrap tire over multilamellar MFI nanosheets in energy field.

Catalytic co-pyrolysis behaviors and kinetics of camellia shell and take-out solid waste using pyrolyzer - gas chromatography/mass spectrometry and thermogravimetric analyzer.

The influences of operating temperature, catalyst types and mixing ratios on co-pyrolysis of camellia shell (CS) and take-out solid waste (TSW) were investigated through orthogonal experiments design. The target was to gain more aliphatic hydrocarbons and monocyclic aromatic hydrocarbons (MAHs) and reduce the production of acids. According to orthogonal experiments results, higher temperature contributed to generate aliphatic hydrocarbons and inhibit formation of acids. Combined utilization of HZSM-5 and CaO was effective to obtain more MAHs and reduce acids. With the improvement of proportion of TSW, the yield of aliphatic hydrocarbons increased and acids decreased. The mixing ratio of CS and TSW was 3:7, 700 °C was chosen as operating temperature and combined utilization of HZSM-5 and CaO were identified. The apparent activation energy (Eave) of CS, TSW and their blends were calculated. 3CS7TSW had the lowest Eave which were 165.33 kJ/mol (by OFW) and 163.14 kJ/mol (by KAS).

Catalytic co-pyrolysis behaviors, product characteristics and kinetics of rural solid waste and chlorella vulgaris.

Catalytic and non-catalytic co-pyrolysis behaviors, kinetics and products distribution of rural solid waste (RSW) and chlorella vulgaris (CV) were studied by thermogravimetric analysis (TGA) and fixed bed reactor. TGA results showed that co-pyrolysis of RSW and CV presented synergism by decreasing the temperature relating to the first mass loss peak. All the additives reduced residual mass for co-pyrolysis (5.21%, 1.57% and 4.89% for CaO, MgO and HZSM-5). Addition of CaO increased activation energy while HZSM-5 and MgO reduced it. Co-pyrolysis of RSW and CV remarkably reduced carboxylic acids and nitrogenous compounds especially for 1:1 ratio. (30.85% and 25.87%). Catalytic pyrolysis with CaO showed the best results by increasing aliphatic hydrocarbons especially light fraction (5.96%-11.98%), reducing acids (0%-30.85%) and nitrogenous compounds (0.08%-17.26%), causing higher HHV of oil. Overall, catalytic co-pyrolysis of CV and RSW with CaO could obtain bio-oil of higher quality.

Effects of microwave pretreatment on catalytic fast pyrolysis of pine sawdust.

In this work, thermal behavior and pyrolysis products of pine sawdust after treated by different microwave pretreatment condition had been studied. Surface structure of samples getting collapsed after microwave pretreatment and the characteristics of thermal decomposition with CaO addition under four kinds heating rates was investigated by thermogravimetric analyzer. Pyrolysis process was carried and the products composition were detected both on Pyrolysis-Gas Chromatography/Mass Spectrometry. Under the condition of 567 W power treatments for 3 min, the yield of phenols rose from 3.64% to 18.21% and the ketones decreased from 55.80% to 40.27%. The activation energy was calculated by Flynn-Wall-Ozawa method. After microwave pretreatment, the activation energy of pine sawdust reach the maximum increase 7.26% at 329 W for 3 min, which meant that microwave pretreatment had little positive effect on promoting the pyrolysis reaction.

A study on catalytic co-pyrolysis of kitchen waste with tire waste over ZSM-5 using TG-FTIR and Py-GC/MS.

Co-pyrolysis characteristics of kitchen waste (KW) with tire waste (TW) were studied by TGA-FTIR and Py-GC/MS. The kinetic parameters were calculated by Ozawa-Flynn-Wall (OFW) and the Kissinger-Akahira-Sunose (KAS) methods. TGA-FTIR results indicated that CO2, CO, NO, NH3, SO2, CH and CC groups were the main gases released from the pyrolysis process, finding that a certain coupling synergistic interaction occurred between KW and TW. Co-pyrolysis of KW and TW displayed positive synergy in pyrolysis kinetics, especially at the ratio of 5:5 whose apparent activation energy declined 16.78% (by FWO) and 17.54% (by KAS). The Py-GC/MS results found that co-pyrolysis could increase the total peak area of volatile matters (10.92-15.34%). Moreover, co-pyrolysis could increase hydrocarbons (especially for olefins (13.25-37.42%)) and inhibit non-hydrocarbon compounds (about 63%) of volatile products. In brief, co-pyrolysis of KW and TW could be a potential way for improving quality of pyrolysis oil.

Microwave pretreatment power and duration time effects on the catalytic pyrolysis behaviors and kinetics of water hyacinth.

In this work, the power and duration time of microwave pretreatment effects on water hyacinth were the main research objects. Surface structure of water hyacinth was broke by microwave radiation through Scanning Electron Microscope observation and the characteristics of thermal decomposition of water hyacinth with the catalyst under four heating rates was investigated by using the thermogravimetric analyzer. Calcium oxide was chosen to be the additive of the water hyacinth pyrolysis reaction. Pyrolysis product compositions were figured out by Pyrolysis-Gas Chromatography/Mass Spectrometry. The results showed that microwave changed the product composition effectively. Under optimal conditions, acids yield of water hyacinth decreased from 7.89% to 4.89% and the yield of sugars increased from 2.73% to 9.04%. Kinetic parameters were calculated by Flynn-Wall-Ozawa method. Under microwave pretreatment at 329 W and 567 W, the activation energy of water hyacinth first decreased and then rose with duration time increasing.

General distributed activation energy model (G-DAEM) on co-pyrolysis kinetics of bagasse and sewage sludge.

In this work, pyrolysis kinetic evolution of mixture of bagasse and sewage sludge with 10%, 30% and 50% (respect to dry initial weight). In terms of kinetic mechanism, the uncertainty of the activation energy obtained by mode-free method was barely known. We found that increasing number of heating rates made result more reliable, but the modeling process more dependent on redundant experiments with extra data. We adapted a novel general distributed activation energy model (G-DAEM) with 5 pseudocomponents for the analysis of kinetic evolution with proposing a more applicable approximation to the general temperature integral. The G-DAEM was trained by data for 20 K/min, and the predictions were performed on data for 15 K/min and 25 K/min. The predictions were well matched to the experimental data. The G-DAEM enhances modeling efficiency of kinetics and provides a effective pathway for high precise model of complicated co-pyrolysis process.

Microwave-assisted co-pyrolysis of Chlorella vulgaris and wood sawdust using different additives.

The microwave-assisted co-pyrolysis of Chlorella vulgaris (CV), wood sawdust (WS) and their blends with additives were investigated. There was a higher liquid and solid yield with silicon carbide (SiC) than activated carbon (AC) in most of samples. Microwave-assisted pyrolysis with additives behaved a positive effect on deoxygenation and aromatization, but not apparent denitrification. With the increase of CV proportion, aromatic hydrocarbons decreased, but aliphatic hydrocarbons increased using AC. High selectivity of phenols was reached at the sample of WS (relative content as 43.6%) using SiC; High selectivity of alkenes was reached at the sample of CV (relative content as 31.2%) and alkanes at the blend sample of 70% CV and 30% WS (relative content as 9.45%). Bio-oil and biochar from microwave-assisted pyrolysis of WS had higher calorific value than that of CV both with AC and SiC. Calorific value of bio-oil decreased by 33.3% after mixing CV with WS.

A study on microwave-assisted fast co-pyrolysis of chlorella and tire in the N2 and CO2 atmospheres.

The microwave-assisted fast co-pyrolysis of chlorella and tire with additive under N2 and CO2 atmospheres were investigated. The pyrolysis profiles, yields of three-phase, the chemical composition of liquid and the ultimate analyses of solid residues were gained. With the tire ratio increasing, all the characters had the changes. The finial temperature had a wave change. The yield of liquid decreased and the chemical composition obtained in liquid of oxygenates compounds decreased, while hydrocarbon compounds increased, among which aromatic hydrocarbons had the highest content. The yield of solid increased, the HHV had a wave change and the values of H/C decreased. Under CO2 atmosphere, the final temperatures were lower with 70% and 100% chlorella ratios, the yield difference of liquid reached the minimal with 70% and 30% chlorella ratios. According to the quantity and quality of liquid and solid, and the former results, 50% percentage of tire was the suitable ratio.

Co-pyrolysis kinetics of sewage sludge and bagasse using multiple normal distributed activation energy model (M-DAEM).

In this study, the kinetic models of bagasse, sewage sludge and their mixture were established by the multiple normal distributed activation energy model. Blending with sewage sludge, the initial temperature declined from 437 K to 418 K. The pyrolytic species could be divided into five categories, including analogous hemicelluloses I, hemicelluloses II, cellulose, lignin and bio-char. In these species, the average activation energies and the deviations situated at reasonable ranges of 166.4673-323.7261 kJ/mol and 0.1063-35.2973 kJ/mol, respectively, which were conformed to the references. The kinetic models were well matched to experimental data, and the R2 were greater than 99.999%y. In the local sensitivity analysis, the distributed average activation energy had stronger effect on the robustness than other kinetic parameters. And the content of pyrolytic species determined which series of kinetic parameters were more important.

Ultrasonic pretreatment effects on the co-pyrolysis of municipal solid waste and paper sludge through orthogonal test.

In this study, the influences of ultrasonic pretreatment factors (frequency, power, treatment time) on blends of municipal solid waste (MSW) and paper sludge (PS) with additive (MgO) was explored, through orthogonal experiments design. The optimum operating condition wanted to be acquired. However, for the ultimate (H/C) and ash analysis after pretreatment, solid residue mass and oxygenates compounds contents in products, the influences of factors were in different results. With adding PS unceasingly, the contents of hydrocarbon compounds decreased. And the ultrasonic pretreatment had the obvious influence with high PS percentage. Longer treatment time resulted to the lower content of oxygenates compounds. After adding MgO, the residue mass reduced, which meant MgO had the catalytic action, and the oxygenates compounds content reduced only with 100 kHz, which had the sonochemical effect.

Adaptive Neural Output Feedback Control for Nonstrict-Feedback Stochastic Nonlinear Systems With Unknown Backlash-Like Hysteresis and Unknown Control Directions.

This paper investigates the problem of output feedback adaptive stabilization for a class of nonstrict-feedback stochastic nonlinear systems with both unknown backlashlike hysteresis and unknown control directions. A new linear state transformation is applied to the original system, and then, control design for the new system becomes feasible. By combining the neural network's (NN's) parameterization, variable separation technique, and Nussbaum gain function method, an input-driven observer-based adaptive NN control scheme, which involves only one parameter to be updated, is developed for such systems. All closed-loop signals are bounded in probability and the error signals remain semiglobally bounded in the fourth moment (or mean square). Finally, the effectiveness and the applicability of the proposed control design are verified by two simulation examples.

Hydrothermal carbonization of typical components of municipal solid waste for deriving hydrochars and their combustion behavior.

In this work, five typical components were employed as representative pseudo-components to indirectly complete previous established simulation system during hydrothermal carbonization (HTC) of municipal solid waste. The fuel characteristics and combustion behavior of HTC-derived hydrochars were evaluated. Results clearly illustrated that the energy ranks of hydrochars were upgraded after HTC. For paper and wood, superior combustion performances of their hydrochars could achieve under suitable conditions. While for food, none positive enrichments on combustion loss rate were observed for hydrochars due to its high solubilization and decomposition under hot compressed water. It was noteworthy that a new weight loss peak was detected for paper and food, suggesting that new compounds were formed. For rubber, the HTC process made the properties of styrene butadiene rubber more close to natural rubber. Therefore, the first peak of hydrochars became significantly intense. While for plastic, only physical changes of polypropylene and polyethylene were observed.