Effect Of Pyrolysis Conditions Research Articles

Analytical and applied pyrolysis of challenging biomass feedstocks: Effect of pyrolysis conditions on product yield and composition

Pyrolysis of challenging Indian and Finnish feedstocks, viz., rice straw, empty oil palm fruit bunch, pine bark, and birch bark, has been studied using analytical and applied pyrolysis reactors. Round-robin characterization of the feedstocks, including elemental analysis, proximate analysis, bomb calorimetry, and thermogravimetric analysis (TGA) was performed to generate robust data. Pyrolysis studies were carried out using an analytical micro pyrolyzer coupled with a gas chromatograph/mass spectrometer (Py-GC/MS), a single particle reactor (SPR), and a batch microwave pyrolysis reactor (MWP) to shed light on the influence of heating rate and mechanism on pyrolysis product yields and composition. The Py-GC/MS and SPR experiments were performed at 400, 500, and 600 °C, while the MWP experiments were carried out at 500 °C. The TGA results showed that the decomposition temperature regimes for the hemicellulose, cellulose, and lignin components of the biomasses overlapped to a certain extent. The condensable pyrolysis vapor (“bio-oil”) yields obtained from pyrolysis of the samples in the SPR reached a maximum at 500 °C. However, the pyrolysis char yield decreased, and the CO and CO2 gas yields increased with temperature in the temperature range of 400–600 °C. The bio-oil yields obtained from the MWP at 500 °C were low, and the char and CO/CO2 gas yields were high compared to the corresponding yields obtained from the SPR at the same temperature. The low bio-oil yields, and high biochar and CO/CO2 gas yields from the MWP were attributed to the slow heating rate in the MWP. The Py-GC/MS analysis results revealed that the pyrolysates were mainly composed of linear and cyclic oxygenated hydrocarbons and phenolics. However, the bio-oils obtained from pyrolysis of the samples in the MWP mainly contained phenolics. The results of the present work indicate that differences in the chemical composition of the biomass feedstocks (especially in the content of alkali and alkaline earth metals), the heating rates and the heating mechanisms played a major role in determining the pyrolysis product yields and compositions.

Effect of pyrolysis conditions on chemical properties of carbonized rice husks for efficient NH4+ adsorption

Ammonium ions (NH4+) are commonly found in contaminated water and are a contributing factor to water eutrophication. Carbonized rice husk, derived from various biomass sources, possesses a porous structure, and its characteristics are influenced by the feedstock and pyrolysis conditions. Hence, this study aimed to investigate the applicability of carbonized rice husk as an absorbent for NH4+ removal. The adsorption kinetics were analyzed using the Pseudo-first-order and Pseudo-second-order models, while the adsorption characteristics were assessed using the Langmuir and Freundlich isotherms. The adsorption rate of NH4+ by carbonized rice husk increased until 240 min and then gradually approached equilibrium state. Notably, the highest NH4+ adsorption rate was observed in pH 7.1 carbonized rice husk 36.045 mg/g∙min. Moreover, the NH4+ adsorption capacity exhibited an increase with increasing concentration and quantity of the solution. The pH of the carbonized rice husk was found to influence the NH4+ adsorption process, with higher pH values corresponding to increased NH4+ adsorption rates. The NH4+ sorption rate carbonized rice husk was higher in pH 11.0 at 31.440 mg/g compared to pH 6.1 (7.642 mg/g) and pH 7.1 (10.761 mg/g). These findings highlight the impact of pyrolysis conditions on the adsorption characteristics of carbonized rice husk.

Effects of pyrolysis conditions and heteroatom modification on the polycyclic aromatic hydrocarbons profile of biochar prepared from sorghum distillery residues

The formation of 2- to 6-ring polycyclic aromatic hydrocarbons (PAHs) in sorghum distillery residue-derived biochar (SDRBC) was evaluated under different thermochemical pyrolysis conditions of carbonization atmosphere (N2 or CO2), temperature (300–900 °C) and doping with nonmetallic elements, i.e., N, B, O, P, N + B, and N + S. The results indicated that without surface modification, PAHs formation was 944 ± 74 ng g–1, the highest level, and 181 ± 16 ng g–1, the lowest level, at 300 °C in N2 and CO2 atmosphere, respectively. Boron doping of SDRBC significantly reduced the PAHs content (by 97%) under N2 at 300 °C. Results demonstrated that boron modified SDRBC exhibited the highest degree of PAHs reduction. Combined pyrolysis temperature and atmosphere in addition to heteroatom doping is a robust and viable strategy for efficient suppression of PAHs formation and high-value utilization of pyrolysis products of low carbon footprint.

Effect of Pyrolysis Conditions on the MOFs-Derived Zinc-Based Catalysts in Acetylene Acetoxylation

The preparation method and calcination temperature of metal-organic framework (MOFs)-derived materials are critical factors affecting catalytic performance. In this work, the preparation conditions of MOFS precursors were optimized, and zinc-based catalysts with different activities (MOF5-700, MOF5-750, and MOF5-800) were obtained by pyrolysis of MOFS precursors under nitrogen, which were then applied to an acetylene acetoxylation reaction system. According to the results, the conversion rate of acetic acid under catalysis was significantly different. (MOF5-700 (48%), MOF5-750 (62%), and MOF5-800 (22%)). Comparing the activity of the catalyst with the industrial catalyst Zn(OAc)2/AC (20%), MOF5-750 showed higher activity, and the acetic acid conversion rate remained around 60% after 50 h of stability testing. By characterization analysis, MOFs-derived materials were obtained after proper temperature pyrolysis. They have high mesoporous content, defects, and oxygen-containing functional groups and can maintain a good crystal structure, greatly reducing the loss of active components. This is the main reason for the good performance of the MOF5-750 catalyst in acetylene acetoxylation. Thus, the preparation conditions and favorable pyrolysis temperature of MOF derivative catalysts play a key role in the catalytic performance of acetylene acetoxylation.

Rational design of cobalt catalysts embedded in N-Doped carbon for the alcohol dehydrogenation to carboxylic acids

In this work, a series of Co catalysts (namely Co@NC) was designed and developed from the thermal treatment of ZIF-67. Through extensive screening of various parameters, Co@NC700-H2/Ar exhibited the best catalytic performance in the acceptorless alcohol dehydrogenation to carboxylic acids. It was worth noting that Co@NC700-H2/Ar enabled the efficient synthesis of various aromatic and aliphatic carboxylic acids in moderate to high yields. Besides, it was recyclable for 9 consecutive cycles without activity decay. Moreover, the effects of pyrolysis conditions on the catalytic performance of the resulting materials were thoroughly examined, and the rationale for the superiority of Co@NC700-H2/Ar over the other prepared materials was also provided. Specifically, the pyrolysis atmosphere applying 95% of Ar gas and 5% of H2 gas (H2/Ar) resulted in the generation of ideal porosity and carbon nanotubes (CNTs), while utilizing 700 °C as the optimized pyrolysis temperature was ascribed to the comprehensive evaluation of materials crystallinity and defective structures. Furthermore, additional insights were gained by systematically exploring the oxidation states of Co in different catalysts. It was proposed that the Co–N species played a crucial role in this catalysis, while the contribution of other Co species, including Co0 and Co–O, could not be neglected. Finally, a plausible reaction mechanism was proposed based on the above observations and related literature reports.

Pyrolytic Conversion of Vomitoxin-Contaminated Corn into Value-Added Products

Deoxynivalenol (DON) (also called vomitoxin) is a mycotoxin caused by pathogens that periodically contaminate crops such as maize, wheat, barley, oats, and rye, making them unusable. We explored pyrolysis as a process for the decontamination of vomitoxin-corn grains and their transformation into value-added products. Pyrolysis was carried out in a bench-scale batch reactor at maximum temperatures between 450 and 650 °C. This resulted in the total destruction of DON, from 5–7 ppm in raw corn grains to non-detectable levels in the treated bio-char. The effect of pyrolysis conditions, including temperature and heating rate, on the conversion of toxic corn grains was investigated. The maximum bio-oil yield was achieved at 650 °C (47 wt.%). The co-products were bio-char (29 wt.%) and non-condensable gases (24 wt.%). Acetic acid and levoglucosan were the two major valuable components in the bio-oil, corresponding to 26 g/kg and 13 g/kg of bio-oil, respectively. The bio-chars were analyzed and upgraded by physical activation using CO2 at 900 °C. Activation increased the bio-char surface area to 419 m2g−1 and promoted pore development, which was verified by SEM. Proximate analysis illustrated that stable carbon increased to 88.8% after activation compared to 10.9% in the raw corn. FT-IR results showed that the thermally unstable functional groups had been completely eliminated after activation. All characterization results confirmed that the activated corn bio-char has excellent potential for adsorption processes. The HHV of the non-condensable gas stream was 16.46 MJ/Nm3, showing the potential application of this product as an energy source.

Co-pyrolysis of corn stalk and coal fly ash: A case study on catalytic pyrolysis behavior, bio-oil yield and its characteristics

In this paper, industrial solid waste coal fly ash and agricultural solid waste corn stalk were used as the research object. The aim is to realize the comprehensive utilization of solid waste and obtain high-quality bio-oil. Thus, the effects of pyrolysis conditions on the pyrolysis process were discussed, and the catalytic effects of coal fly ash were explored using the TGA, SEM-EDS, XRD, FTIR, and GC-MS. The results of TGA coupled with the Coats-Redfern model indicate that the total apparent activation energy varied from 408.40 kJ/mol to 387.39 kJ/mol and co-pyrolysis is a endothermic process while the initial pyrolysis temperature(T i ) is advanced after adding coal fly ash. The highest yield of bio-oil is 30.06 ± 0.03 wt%. It is obtained at 500 °C with a 50% mass fraction of coal fly ash. Additionally, ketonization reactions are promoted, leading to the content of ketones in bio-oil increased by about 10.28%. The selectivity of hydrocarbons is also improved, especially, aliphatic hydrocarbons increase by about 7.89%. The reasons are deeply analyzed and discussed. Overall, the results demonstrate that the participation of coal fly ash not only improves the pyrolysis behavior of biomass but also promotes the enrichment of ketone chemicals in the bio-oil.

Study on the Effect of Pyrolysis Conditions on the Combustion Behavior and Char Structure Evolution.

Pyrolysis polygeneration technology has been widely applied due to its wide adaptability to coal types and mild reaction conditions. In this paper, the in situ process test combining pyrolysis and combustion of Pingshuo coal was carried out using a thermogravimetric analyzer and a fluidized-bed reactor. The influence of pyrolysis conditions on the combustion behavior and char structure was studied. The reduction of the pyrolysis temperature and the increase in pyrolysis residence time resulted in a lower burnout temperature of char, thereby improving the combustion characteristics of char. Furthermore, the maximum CO2 release rate reached 2.8 mg/(g·s) during the combustion process. The decrease in the pyrolysis temperature was conducive to the increase of CO2 release mass, suggesting a more complete burning of char. The char combustion process was mainly controlled by the chemical reaction according to the reaction kinetics study. The apparent rate constant of the combustion process increased gradually with the decrease in the pyrolysis temperature of char, and the rate of the combustion reaction increased, which contributed to the enhancement of the combustion performance of the char within the range of 850–950 °C. Meanwhile, the crystal structure inside the char changed significantly after different pyrolysis conditions. However, it had little influence on the molar content of carbon structure, which suggested that the amount of CO2 released was mainly caused by the different resistances of oxygen diffusion to the reaction interface.

Synthesis of Biochar From Lignocellulosic Biomass for Diverse Industrial Applications and Energy Harvesting: Effects of Pyrolysis Conditions on the Physicochemical Properties of Biochar

The excessive dependency on fossil fuel resources could be curtailed by the efficient conversion of lignocellulosic biomass. Biochar, a porous carbonaceous product synthesized exploiting thermochemical conversion pathway, could be an environment-friendly replacement of fossil fuel resources. Slow pyrolysis, a sub-class among various thermochemical conversion techniques, has gained immense popularity owing to its potential to convert biomass to biochar. Furthermore, biochar obtained as the by-product of slow pyrolysis has attracted enormous popularity due to its proven role and application in the multidisciplinary areas of engineering and environmental remediation applications. The physicochemical quality of biochar and its performance is significantly dependent on the feedstock type and pyrolysis process parameters. Therefore, further experimental research and investigations in terms of lignocellulose biomass type and pyrolytic process parameters (temperature, heating rate and reaction time) are essential to produce biochar with desired physicochemical features for effective utilization. This review presents an updated report on slow pyrolysis of lignocellulosic biomass, impact of different pyrolysis parameters and degradation pathway involved in the evolution properties of biomass. The influence of the feedstock type and lignocellulosic composition on the biochar properties are also discussed meticulously. The co-relationship between biochar yield at different pyrolysis temperatures and the development of textural properties provides valuable information for their effective utilization as a functional carbon material. Additionally, an extensive study was undertaken to collate and discuss the excellent physicochemical characteristics of biochar and summarizes the benefits of biochar application for diverse industrial purposes. Biochar is acknowledged for its excellent physicochemical properties owing to the thermal treatment and as a result its prospective diverse industrial applications such as for soil treatment, carbon sequestration, adsorbent (wastewater treatment or CO2 capture), producing activated carbon for gold recovery, energy storage and supercapacitor are summarized systematically in this review paper. For instance, biochar when applied in soil have shown improvement in soil respiration by 1.9 times. Furthermore, biochar when used to capture CO2 from flue gas stream under post-combustion scenario has demonstrated superior capture performance (2.8 mmol/g) compared to commercial activated carbon. This paper identified the knowledge gaps and outlooks in the field of the advancements of biochar from slow pyrolysis for targeted engineering applications mainly in the field of environmental remediation and energy harvesting.

Pyrolysis of domestic sewage sludge: influence of operational conditions on the product yields using factorial design

This study aims to investigate a sustainable method for sewage sludge (SS) safe disposal and reuse. The study involved exploring the optimum parameters of thermal treatment of SS by pyrolysis to produce biochar. Based on the analysis of the full factorial design, the effects of pyrolysis conditions: temperature, heating rate, and isothermal time on pyrolysis product yields were evaluated. The average yield of biochar was significantly reduced when the pyrolysis temperature was increased from 300 to 500 °C, while the average yields of bio-oil (BO) and non-condensable gases (NCGs) were increased. The yield of biochar was nearly the same when the heating rate was increased from 5 to 35 °C/min, while the yield of BO was increased and the yield of NCGs was decreased. The average yields of biochar and NCGs were reduced when the isothermal time was increased from 45 to 120 min, while the yield of BO was slightly increased. Factorial design methodology revealed all potential interactions between the variables of the pyrolysis process of SS. To predict pyrolysis product yields, first-order regression models were developed based on the effects’ magnitude of the process parameters and their interactions. The models were agreed to the experimental data.

Influence of pyrolysis conditions on the mercury removal characteristics and physicochemical properties of biomass coke

Effects of pyrolysis conditions, including pyrolysis temperatures, pyrolysis atmosphere, and heating rate, on Hg0 removal of wood chip-based biomass coke (BC) under the basic simulated flue gas were systematically studied. The BET, SEM, FTIR, XPS and Hg-TPD were used to analyze the physicochemical properties and specific mercury compounds. The results show that the final pyrolysis temperature and pyrolysis atmosphere have greater influence on the mercury removal performance while heating rate affects little. The BC-N2 + 7%O2-800-10 has the best Hg0 removal efficiency under all the pyrolysis conditions, mainly due to the good pore structure and abundant surface oxygen-containing functional group. N2 + 7% O2, higher pyrolysis temperature and heating rate benefit for BC’s pore structure development. Oxygen-containing functional groups of OH, CO and COO are the main functional groups on the BC surface, which promotes Hg0 adsorption. The physically adsorbed Hg0 and more chemically adsorbed HgO are the main mercury compounds in the used BC.

The characteristics and mechanism for the formation of tars from low temperature pyrolysis of lignite

In this paper, the effect of pyrolysis conditions on low-temperature formation of tars characteristics and viscosity of lignite was investigated in a self-researched fixed bed reactor. The relationship between tar quality parameters and its formation and viscosity characteristics was investigated by multiple linear regression. The composition characteristics of low temperature tar were also investigated. The results showed that the yield and viscosity of tar increased with the increase of heating rate and pyrolysis temperature. Low temperature tar started to escape at 350 °C and reaches a maximum at 600 °C. The maximum tar yield was obtained at 550 °C–600 °C, 0.31%/min. The tar viscosity increased significantly after 550 °C, and the tar yield of isothermal pyrolysis was higher than that of non-isothermal pyrolysis after 500 °C. The tar yield under hydrogen atmosphere was higher than that under nitrogen, carbon dioxide, methane and carbon monoxide atmosphere. The tar yield increased gradually with the increasing of H2 flow rate, until it reached the maximum at the flow rate of 720 ml/min, which was 12.58%. The mathematical models of tar formation and viscosity characteristics of Yunnan lignite during low temperature pyrolysis were Yieldtar ( % )=12.14 H/C+48.35O/C−12.54fa+0.29Ad and Viscositytar( mPa⋅s )=14.99 H/C+62.53O/C−0.39fa, respectively. The content of aliphatic and aromatic components in tar increased with the increase of pyrolysis temperature, while the content of polar substances decreased gradually. The content of aliphatic and aromatic components was more than 53%, and the polar compounds content dropped to about 41.7% at 600 °C.

Effect of Pyrolysis Conditions on the Performance of Co–Doped MOF–Derived Carbon Catalysts for Oxygen Reduction Reaction

MOF–derived porous carbon is a type of promising catalyst to replace expensive Pt–based catalysts for oxygen reduction reaction (ORR). The catalytic activity for ORR depends closely on pyrolysis conditions. In this work, a Co–doped ZIF–8 material was chosen as a research object. The effect of pyrolysis conditions (temperature, heating rate, two–step heating) on the ORR performance of ZIF–derived carbon catalysts was systematically studied. The Co–ZIF–8 catalyst carbonized at 900 °C exhibits better ORR catalytic activity than that carbonized at 800 °C and 1000 °C. Moreover, a low heating rate can enhance catalytic activity. Two–step pyrolysis is proven to be an effective way to improve the performance of catalysts. Reducing the heating rate in the low–temperature stage is more beneficial to the ORR performance, compared to the heating rate in the high–temperature stage. The results show that the Co–ZIF–8 catalyst exhibits the best performance when the precursor was heated to 350 °C at 2 °C/min, and then heated to 900 °C at 5 °C/min. The optimum Co–ZIF–8 catalyst shows a half–wave potential of 0.82 V and a current density of 5.2 mA·cm−2 in 0.1 M KOH solution. It also exhibits high content of defects and good graphitization. TEM mapping shows that Co and N atoms are highly dispersed in the polyhedral carbon skeleton. However, two–step pyrolysis has no significant effect on the stability of the catalyst.

Effect of pyrolysis conditions on environmentally persistent free radicals (EPFRs) in biochar from co-pyrolysis of urea and cellulose

Biochar derived from nitrogen-rich pyrolysis of biomass can be used as a soil conditioner, but it contains a large amount of environmental persistent free radicals (EPFRs). EPFRs are a newly identified environmentally harmful substance, and the detection and research on EPFRs in nitrogen-rich pyrolyzed char is lacking. Biochars prepared from cellulose-urea mixtures at different temperatures, residence times, and urea ratios were analyzed in this study. EPFRs in biochar prepared at 500 °C had the highest spin concentrations. Substituted aromatic compounds were the precursors to the EPFRs. The types of EPFRs in biochars shifted from oxygen-centered at 400 °C to carbon- and oxygen-centered in the 450–600 °C range due to a reduction in oxygen-containing functional groups. Residence time experiments showed that most EPFRs formed in the first 5 min of pyrolysis. C was the main element used for the formation of EPFRs, while N content was negatively correlated with the concentration of EPFRs. Pyrolysis temperature was the key factor determining the types of EPFRs produced, while proportion of urea only affected the concentrations of EPFRs and not type. The results of this study are of great significance for understanding the environmental behavior of common EPFRs in nitrogen-rich biochar.

The Effect of Pyrolysis Conditions on the Preparation of Fe2O3 Particles Using Simulated Pickling Liquor in a Venturi Reactor

Large amounts of pickling liquor are produced during the pickling of iron and steel. The Venturi reactor is used during the pyrolysis of pickling liquor to prepare high-purity Fe2O3 particles. Changing the pyrolysis conditions will affect the purity and concentration of Fe2O3 particles. In this paper, physical experiments and numerical simulations were carried out to study the effect of pyrolysis conditions on the Fe2O3 particles, including the pyrolysis temperature, the FeCl2/FeCl3 ratio in the pickling liquor, and the citric acid ratio. The results showed that a product with a higher purity, better crystallinity, and greater concentration was obtained at 923 K. Further increasing the temperature did not change the concentration of Fe2O3 particles. When the ratio of FeCl2/FeCl3 in the pickling liquor was 1:1.5, the maximum concentration of Fe2O3 particles at the outlet was obtained. When the added proportion of citric acid was 1:1, the particle size distribution was more uniform, and when the added proportion was 1:2.5, the maximum concentration of Fe2O3 particles at the outlet was achieved.

Machine learning prediction of pyrolytic gas yield and compositions with feature reduction methods: Effects of pyrolysis conditions and biomass characteristics

This study aimed to utilize machine learning algorithems combined with feature reduction for predicting pyrolytic gas yield and compositions based on pyrolysis conditions and biomass characteristics. To this end, random forest (RF) and support vector machine (SVM) was introduced and compared. The results suggested that six features were adequate to accurately forecast (R2 > 0.85, RMSE < 5.7%) the yield while the compositions only required three. Moreover, the profound information behind the models was extracted. The relative contribution of pyrolysis conditions was higher than that of biomass characteristics for yield (55%), CO2 (73%), and H2 (81%), which was inverse for CO (12%) and CH4 (38%). Furthermore, partial dependence analysis quantified the effects of both reduced features and their interactions exerted on pyrolysis process. This study provided references for pyrolytic gas production and upgrading in a more convenient manner with fewer features and extended the knowledge into the biomass pyrolysis process.

Effects of various pyrolysis conditions and feedstock compositions on the physicochemical characteristics of cow manure-derived biochar

Pyrolysis, as a thermal decomposition process and environment-friendly technology, can be used for the safe treatment of cow manure. In this paper, the effects of pyrolysis conditions on the properties of biochar derived from different types of cow manure (i.e., fresh cow manure, flushing cow manure, and anaerobic fermentation residues) were studied using slow pyrolysis methods. The properties of feedstocks, thermal decomposition, and biochar were analyzed using elemental analysis, coarse fiber determination, TG–FTIR, ICP–MS, FTIR, XRD, and SEM–EDS. Results showed that the cow manure-derived feedstocks were rich in total organic C (>37%) and had no heavy metal risk. According to the results of TG–FTIR, pyrolysis produced more residual solids, CO, CH4, and NH3 and less CO2 than combustion. The factors affecting alkalinity, calorific value, adsorption capacity, and surface functional group properties of cow manure-derived biochar in order of effectiveness were as follows: pyrolysis temperature > manure characteristics > heating rate > residence time. In general, increasing the temperature from 300 °C to 700 °C increased the pH (8.05–11.74) and C content (45.75%–49.64%) of fresh cow manure biochar and decreased the yield (62.17%–39.82%), nutrient content (N + P + K = 6.90%–5.64%), iodine adsorption capacity (269–96 mg g−1), aromaticity, and polarity. The biochar derived from flushing cow manure and anaerobic fermentation residues had similar C content (>48%), alkalinity (pH > 10), calorific value (>20000 J g−1), stability, and polarity. Fresh cow manure biochar had higher nutrient recovery (6.6%) and iodine adsorption capacity (215 mg g−1) than others. Compared with flushing cow manure and anaerobic fermentation residues, the pyrolysis of fresh cow manure reduced nutrient loss and treatment energy consumption. This study provides a good basis for the optimization of the pyrolysis process of three typical kinds of cow manures in dairy farms.

Effect of pyrolysis conditions on food waste conversion to biochar as a coagulant aid for wastewater treatment

Food waste (FW) treatment via pyrolysis can be a promising method to reduce the amount of FW and produce value-added products such as biochar. In this study, FW was converted to food waste-based biochar (FWB) as a coagulant aid for wastewater treatment. The solution pH increasing ability of FWB prepared at different pyrolysis temperatures (350, 450, 550, 650, 750, and 850 °C), pyrolysis time (1, 2, 4, 6, and 8 h), and heating rates (5, 10, and 20 °C/min) were compared by mixing biochar and deionized water (1:5 (w/v)) for 30 min, and their physicochemical properties were characterized by FTIR, XRD, and XRF analyses. The optimum pyrolysis conditions for FWB to increase the solution pH were 750 °C, 10 °C/min, and 6 h. Copper coagulation was significantly enhanced as the FWB dose increased along with polyaluminum chloride (PAC). Moreover, the addition of FWB as a coagulation aid improved sludge dewaterability and organic dye removal. Furthermore, the combination of FWB and PAC could also be used to treat industrial plating wastewater containing various heavy metals at different concentrations, which makes FWB a promising coagulation aid.

Fast fabrication of SiC particulate-reinforced SiC composites by modified PIP process using spark plasma sintering – effects of green density and heating rate

SiC particulate-reinforced SiC ceramic matrix composites (SiCp/SiC) were fabricated by a modified polymer infiltration and pyrolysis (PIP) process using spark plasma sintering (SPS). The effects of pyrolysis conditions, green density, and polymer infiltration method on the densification and properties of the SiCp/SiC were investigated. SiCp/SiC with high relative density up to 88.06 % was fabricated after 4 PIP cycles by adopting high green density of SiC pellet (76.5 %) provided from drying the high solid loaded (70 vol. %) SiC slurry and fast SPS pyrolysis. The highest hardness of 21.05 ± 2.4 GPa was achieved for the as-fabricated SiCp/SiC, and the hardness value increased up to 23.99 ± 1.8 GPa after heat treatment at 2000℃. The improvement was attributed to the thermally stable SiC fillers, and partial sintering between the fillers and precursor derived ceramics (PDC) matrix. The excellent mechanical property, thermal stability, and short processing time render the SiCp/SiC composite a challenging candidate for high-temperature application.

Effects of pyrolysis temperature and reaction time on the performance of swine-manure-derived bio-binder

Swine-manure-derived bio-binder can solve the problem of environmental pollution caused by the accumulation of solid waste from swine manure, and realize the replacement of asphalt by sustainable road construction materials. The main purpose of this study is to study the influence of pyrolysis conditions on the performance of swine-manure-derived bio-binder, the swine manure particles were cracked at 5 pyrolysis temperatures and 2 reaction times. Ten kinds of swine-manure-derived bio-oil were prepared, and 15% bio-oil were used to partially replace petroleum asphalt to prepare corresponding bio-binder. The effects of pyrolysis conditions on the penetration, softening point, ductility, water absorption and the rheological properties of bio-binder were tested. The results show that the maximum bio-oil yield of 1 s reaction time at 550 °C pyrolysis temperature was 45.1%. The high temperature stability of bio-binder is better than that of virgin asphalt. The high temperature stability of bio-binder gradually decreases with the pyrolysis temperature and reaction time of bio-oil. The fatigue performance and low-temperature crack resistance of the bio-binder are poorer than that of virgin asphalt on the low pyrolysis temperature, but those performances will be gradually improved with the pyrolysis temperature. The low-temperature crack resistance of the binder can be improved by prolonging the cracking reaction time under a certain pyrolysis temperature. Considering the yield of bio-oil and the performance of bio-binder comprehensively, the swine-manure-derived bio-oil at a pyrolysis temperature of 550 °C and a reaction time of 1 s is the most suitable for the preparation of bio-binder.