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This study investigates the potential of applying pressurized chemical looping reforming (CLR) mechanism for syngas to methanol production process combining of experimental demonstration of methane reforming to syngas and simulation for integration in methanol production. The experimental study was conducted using the internally circulating reactor (ICR) that was specially designed to enable pressurized CLR operation where several experimental cases were completed using a NiO-based oxygen carrier. Up to 4 kW of methane feed was reformed to syngas, achieving high conversion efficiencies and high syngas recovery and purity at pressurized conditions up to 4 bar. Co-feeding H2O or CO2 was found to affect mainly the H2/CO ratio. The simulation study evaluated the potential of integrating the CLR process for large scale methanol production through comprehensive thermodynamic analysis using Aspen plus. The results revealed that CLR-based methanol plant is a highly attractive pathway achieving higher methanol production efficiency outperforming the conventional autothermal reforming (ATR) -based plant by ∼5% efficiency. The main benefits of the CLR-based system is the avoidance of the air separation unit required for ATR plants, and the extra power generation through the gas turbine utilizing the hot exhaust gas of the air reactor. A detailed sensitivity study was also conducted to study the effects of the CLR operating pressure, and the reduced syngas purity caused by possible gas leakage in the ICR, on the overall methanol plant performance.

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To achieve different products distributions and improve energy conversion performance for the coal utilization with zero carbon emission, an advanced polygeneration system incorporating the methanol synthesis and Allam power cycle (an oxy-combustion, direct-fired supercritical carbon dioxide Brayton cycle) is proposed. The water-gas shift reaction is combined with the syngas recycle to obtain different products (i.e., methanol and electric power) distributions. Moreover, different from the conventional coal-to-methanol process, the carbon dioxide generated by the shift reaction is not separated from the shifted syngas but enters the Allam cycle, which can be simply split from the cooled exhaust without additional energy penalty. In other words, the carbon dioxide separation energy penalty of the methanol production is reduced to zero by connecting the coal-to-methanol process and the Allam cycle. In this study, the material flow and energy conversion characteristics of the proposed polygeneration system is revealed. The influences of the carbon monoxide shift ratio and syngas recycle ratio on the methanol productivity, net electric power throughput and the corresponding fuel saving ratio are comprehensively analyzed. The optimum strategy of the combination of the water-gas shift reaction and syngas recycle is obtained with the methanol/electricity energy ratio ranging from 0.75 to 2.71; and the highest fuel saving ratio soars to 5.79% as the methanol/electricity ratio is 1.55 at the carbon monoxide shift ratio of 0.17 and the syngas recycle ratio of 0.8.

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Catalyst lifetime and product selectivity of methanol-to-olefins (MTO) catalysis on window-cage type zeolites and zeotypes are examined and interpreted to elucidate the critical role of high-pressure H2 and CO in MTO catalysis at conditions relevant for syngas-to-olefins (STO) conversion (H2/CH3OH >100, CO/CH3OH >100). Propylene co-feed experiments elucidate that acid-catalyzed hydrogenation reactions transpire and enhance olefins-cycle propagation by intercepting formaldehyde-mediated condensation and dehydrocyclization reaction cascades to result in an increase in catalyst lifetime (>7×) and decrease ethylene-to-propylene (∼1.5×) and ethylene-to-butenes ratios (∼1.6×) during MTO with high-pressure H2 co-feeds. CO is mechanistically relevant in increasing ethylene-to-propylene (∼1.5–3.0×) and ethylene-to-butenes ratio (∼1.7×) during MTO catalysis only at high CO (3–8 bar) and syngas pressures (24 bar, H2/CO∼2–16); at these high pressures, CO participates in carbonylation reactions to enhance aromatics-cycle propagation and enable a pathway for ethylene production via methyl acetate formation. These results suggest that high-pressure syngas introduces new catalytic pathways to distinguish MTO catalysis from STO catalysis and MTO catalysis in the presence of high-pressure syngas reagents.

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Utilizing the greenhouse gas CO2 as a feedstock in chemical processing can offer alternative solutions to long-term storage. In this study, a systematic analysis of methanol synthesis performance was analyzed based on both thermodynamic equilibrium and kinetic models using captured CO2 and syngas produced from biogas as feedstock. Using reactor inlet temperature as a parameter, it was found that methanol yield can be enhanced by increasing residential time from increased reactor diameter. The longer reactor can increase the residential time but a large pressure drop caused a decrease in methanol yield. Due to the exothermic reaction nature, methanol yield from an adiabatic reactor is lower than that from the isothermal reactor due to temperature rise. From the results obtained for CO2 hydrogenation, methanol yield can be enhanced by water removal. The CO2 conversion was found to increase with increased reaction temperature due to methanol and carbon monoxide productions. Using CO and CO2 as limiting species, high combined CO and CO2 conversion can be obtained from syngas with low CO2/H2 and high CO/H2 ratios. However, methanol production per mole of H2 depends on the H2 utility instead of combined CO and CO2 conversion. Finally, syngas produced from biogas by using combined dry and steam reforming reactions was used as the feedstock for the methanol synthesis. To obtained the syngas composition suggested from industrial applications, CH4 and H2O were added in the combined reforming process. With higher CH4 content in the biogas, higher methanol production and lower water production can be obtained. With an increased recycle ratio for unreacted syngas, methanol production can be enhanced.

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The conventional configuration of a pulp mill, in which black liquor is concentrated and burnt, is compared to the upgrading gasification routes for methanol (MeOH) or dimethyl ether (DME) co-production. To this end, various exergy-based and environmental impact indicators are assessed in the light of different utility supply scenarios. The combined exergy and energy integration analysis are used to identify potential improvements related to the decarbonization and mitigation of the process irreversibility. As a result, the exergy efficiencies of the conventional scenario and the integrated plants average 40% and 45%, respectively, whereas the overall CO2 emission balances vary from 1.97 to -0.07 tCO2/tPulp, respectively. Additionally, an incremental economic analysis that envisages future carbon taxation scenarios suggests that only MeOH or DME co-production routes with partial electricity import may economically outperform the conventional kraft pulp mill for moderate carbon taxations. These results highlight the relevance of the electricity import from the Brazilian mix for pushing upwards the share of renewable energy resources in the production of traditionally fossil-based fuels and chemicals.

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Methanol produced from chemical transformation of coal derived CO2 rich syngas can be a sustainable replacement for conventional crude oil based fuels with an impressive feature of reducing greenhouse gas emissions. Mostly industrial catalysts are promoted, however, lack of detailed insight into the mechanism of promotion has so far restricted the identification of non-precious promoter. In this work, a series of Cu–Zn–Mn oxide catalysts were synthesized by varying Mn loading from 0 to 30 mol% at pH near 7 and 70 °C via co-precipitation technique to elucidate the role of Mn-promoted malachite precursors in micro structural properties of catalyst. Investigation revealed that incorporating 20 mol% Mn (CuZn:Mn[0.2]) in malachite lattice resulted in better stabilization and dispersion of CuO domains owing to maximum dilution of Cu2+ ions as compared to other three analogous catalysts. Consequently, CuZn:Mn[0.2] catalyst unveiled ∼1.4-fold and ∼1.2-fold increase in CO conversion and methanol selectivity respectively as compared to the unpromoted catalyst. However, Mn loading beyond 20 mol% showed a detrimental effect on the catalytic efficiency due to dominant presence of an additional aurichalcite by-phase which revokes dilution of Cu2+ ions. Co-feeding CO2 in syngas improves dual active sites synergy (Cu0/Cu+) which helps in understanding catalytic mechanism of methanol synthesis. For best performing catalyst, statistically validated non-linear mathematical models were derived using response surface methodology along with central composite design. These models forecasted the correlations between process parameters as well as identified the relative contribution of each parameter. For maximising both methanol selectivity and CO conversion, desirability function predicted the optimum values of reaction temperature, pressure, and feed gas molar ratio (CO/CO2/H2) as 242 °C, 49 bar and 3 respectively. Under these conditions, 46% CO conversion and 93% methanol selectivity were obtained. Thus, the formulated coal to methanol process originating from catalyst design to optimization of process parameters paves the way for sustainable solutions referring to global “3E” issues, viz. energy, environment, and economic challenges.

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Methanol dehydrogenation is an efficient way to produce syngas with high quality. The current efficiency of sunlight-driven methanol dehydrogenation is poor, which is limited by the lack of excellent catalysts and effective methods to convert sunlight into chemicals. Here, we show that atomically substitutional Pt-doped in CeO2 nanosheets (Pts-CeO2) exhibit excellent methanol dehydrogenation activity with 500-hr level catalytic stability, 11 times higher than that of Pt nanoparticles/CeO2. Further, we introduce a photothermal conversion device to heat Pts-CeO2 up to 299°C under 1 sun irradiation owning to efficient full sunlight absorption and low heat dissipation, thus achieving an extraordinarily high methanol dehydrogenation performance with a 481.1 mmol g−1 h−1 of H2 production rate and a high solar-to-hydrogen (STH) efficiency of 32.9%. Our method represents another progress for ambient sunlight-driven stable and active methanol dehydrogenation technology.

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The conversion of carbon oxides (CO + CO2) to methanol is promising enough in concomitant decrease in greenhouse effect along with the mitigation of energy crisis. However, the process still confronts low levels of CO2 conversion and development of highly efficient catalyst is a bid challenge. In the present work, a syngas feed rich in CO2 was employed to produce methanol over a streak of La promoted Cu/ZnO/MgO catalysts where a harmonized synergy between the La and active Cu sites as a function of La content is reported. XRD analysis of Cu/ZnO/MgO/La2O3 precursors indicated the relative concentration of aurichalcite or malachite galleries. The optimized catalyst (2.5 mol% La) demonstrated the amplified population of malachite phase whereas suppression in aurichalcite phase. Presence of mixed phase precursor reflected well in Cu dispersion, small sized stable Cu particles and improved methanol synthesis activity with marginal deterioration in catalytic efficiency over 60 h on stream. A thorough investigation revealed that introducing La not only generated the required moderate basic sites but also enriched the catalytic surface with active Cu. XPS results indicated that La regulates interaction between Cu2+ and La3+ species, ultimately modifying the surface Cu/Zn ratio. CZ-M17.5La2.5 catalyst showed the highest carbon conversion with a methanol selectivity of 72.2% at 260 °C. This proves that La plays a crucial role towards methanol synthesis when blend of CO/CO2 is used as a feed.

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The syngas to methanol (STM) process is an energy-intensive chemical production process, and effective utilization of waste heat can improve energy and economy efficiency. To address current challenges that complex interactions between process synthesis and waste heat recovery are not considered, a novel simultaneous optimization model is proposed for a heat-integrated syngas-to-methanol process with Kalina Cycle (KC) for waste heat recovery, where the identified key parameters of KC and STM are optimized simultaneously without reducing the overall conversion of hydrogen to produce methanol. In developing the model, an enhanced Heat Integration model that considers variable temperatures and flowrates is established to perform thermal cycle optimization with process synthesis by combination of simulation-based modelling approach and equation-based mathematical programming approach. The STM process is synthesized based on a rigorous kinetic modelling approach and the effect of process parameters on waste heat recovery is further analyzed by control variable method. The results show that the net power output of the whole system increases with the decrease of reaction pressure. The optimal medium temperature and inlet temperature of reactor are 180 °C and 160 °C, respectively. Moreover, the presented model can achieve the optimal coupling structure of KC and STM process with the maximized net power output of 15,206.3 kW, which increases by 81.6% compared with that of 8371.4 kW derived by the traditional sequential optimization method in previous study.

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Dedicated bioenergy combined with carbon capture and storage are important elements for the mitigation scenarios to limit the global temperature rise within 1.5 ° C . Thus, the productions of carbon-negative fuels and chemicals from biomass is a key for accelerating global decarbonisation. The conversion of biomass into syngas has a crucial role in the biomass-based decarbonisation routes. Syngas is an intermediate product for a variety of chemical syntheses to produce hydrogen, methanol, dimethyl ether, jet fuels, alkenes, etc. The use of biomass-derived syngas has also been seen as promising for the productions of carbon-negative metal products. This paper reviews several possible technologies for the production of syngas from biomass, especially related to the technological options and challenges of reforming processes. The scope of the review includes partial oxidation (POX), autothermal reforming (ATR), catalytic partial oxidation (CPO), catalytic steam reforming (CSR) and membrane reforming (MR). Special attention is given to the progress of CSR for biomass-derived vapours as it has gained significant interest in recent years. Heat demand and efficiency together with properties of the reformer catalyst were reviewed more deeply, in order to understand and propose solutions to the problems that arise by the reforming of biomass-derived vapours and that need to be addressed in order to implement the technology on a big scale.

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In the present study, the combined steam and dry reforming of methanol (CSDRM) process were performed in the temperature range of 400 °C-900 °C, CO2/H2O ratio of 0.5–2.5 and (CO2+H2O)/CH3OH ratio of 0.5–2.5 at the atmospheric pressure over a Pt/ZrO2 catalyst in fixed bed reactor. The experimental data was applied to model the kinetic of CSDRM reaction based on Langmuir-Hinshelwood (LH) isotherm with one active site on the catalyst surface taking into account. By comparing the two experimental and calculated values, it was seen that error of kinetic model in predicting the experimental methanol conversion was lower (7.97%) than other responses. An almost completed methanol conversion was attained above 800 °C at all values of CO2/H2O ratios except for (CO2 + H2O)/CH3OH ratio of 0.5. The temperature had a positive impact on the H2 and CO yields, however; the dependency of CO yield to temperature was higher than H2 yield. CO2 conversion slightly decreased from 400 °C to 500 °C, while started to increase at temperatures above 500 °C regardless of (CO2+H2O)/CH3OH and CO2/H2O ratios. H2/CO ratio near to 2 which is suitable for Fischer–Tropsch synthesis (FTS) reaction was obtained at (CO2+H2O)/CH3OH ratios bigger than 1.5, a CO2/H2O ratio of 1 and temperature above 800 °C. The methanol conversion values obtained from thermodynamic equilibrium were equal with the experimental data. The reverse water-gas shift reaction quickly happened at temperatures above 700 °C, higher values of CO2/H2O ratio and under excess oxidizing agent, which led to increasing the gap between the experimental data and measured from thermodynamic equilibrium analysis.

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In this work, an integrative assessment of renewable syngas production by solid oxide electrolysis (SOE), which is also called co-electrolysis, was performed to investigate economic and environmental viability based on various renewable energy resources. First of all, economic analysis using itemized cost estimation, predictive cost assessment, and uncertainty analysis through Monte-Carlo simulation was carried out for estimating current and future levelized cost of syngas and possible cost ranges of the syngas production. From these analyses, the economic competitiveness of syngas production can be achieved with simultaneous cost reduction of major economic parameters, such as SOE system cost, CO2 price, and levelized cost of electricity. Furthermore, the low environmental potential of syngas production using some of the renewable energy sources was proved through life-cycle assessment. Finally, analytic hierarchy process was implemented to determine which one is the most feasible renewable energy in the technical, economic, and environmental aspects simultaneously. As a result, renewable syngas production coupling SOE and onshore wind electricity can bring considerable benefits in terms of CO2 utilization and other value-added chemical production.

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The conversion of naphthalene into high value-added intermediate, 2,6-dimethylnaphthalene (2,6-DMN), using methanol as an alkylating agent has been widely studied. However, the low conversion of naphthalene and the easy deactivation of catalysts due to carbon deposition still pose challenges for industrialization. This is attributed mainly to the huge difference in the conversion kinetics of naphthalene and methanol. Herein, we report the first one-step process for the synthesis of 2,6-DMN from naphthalene by direct alkylation with syngas over “ZnAlCrOx&HZSM-5″ bifunctional catalyst. Compared to the traditional alkylation process of naphthalene with methanol, the direct alkylation of naphthalene with syngas not only shortened the process route and improved the reaction balance of syngas to methanol, but also improved the effective utilization rate of CO (29.87 %), naphthalene conversion, and catalyst stability. Results indicated that the alkylation of naphthalene could be improved by appropriately narrowing the spacing between the ZnAlCrOx oxide and HZSM-5. The acid strength and acidity on the external surface of HZSM-5 were modified by P or Si to improve the initial conversion of naphthalene and the selectivity for 2,6-DMN. The difficulty in determining the deactivation point of catalysts with multiple active sites under complex catalytic systems was solved by adopting a strategy of ”improve shortcomings“. The decline of metal activity in this reaction was found to be the main reason for catalyst deactivation. Doping of Ce into ZnAlCrOx helped to improve the stability of the catalyst from 80 h to 120 h.

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Assessment of the recent research on the side-feeding strategy in the methane tri-reforming reactor, suggests that this procedure can be a beneficial method for producing syngas. In the present study, special attention is given to the length of methane tri-reformer due to its significant effect on the residence time of distributed components, reaction pathways, synthesis gas production, and reactor performance in side-feeding procedures. The optimal design of three types of membrane tri-reforming reactor, containing O-MTR, H-MTR, and C-MTR, in which O2, H2O, and CO2 permeate as the distributed reactants through the micro-porous membrane, respectively, as well as the conventional tri-reformer (MTR) was carried out to produce proper syngas for methanol and gas-to-liquid (GTL) units. The results show that the O-MTR offers the most advantages in terms of CH4 conversion (i.e., 99.98%), H2 yield (i.e., 1.91), and catalyst lifetime due to no formation of hot spot temperature. Additionally, the CH4 conversion and H2 yield in the O-MTR increased by 5% compared to the MTR. However, the length of these reactor structures to produce appropriate syngas for Fischer-Tropsch and methanol synthesis processes was in the following order: MTR < C-MTR ‚âÖ O-MTR < H-MTR.

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The catalytic dry reforming of plastic waste is conducted in two-stage fixed bed reactors. The pyrolysis of polypropylene plastics occurs in the first reactor, and the pyrolyzed gases undergo a reforming reaction with carbon dioxide over a catalyst in the second reactor. The wet impregnation method is used to synthesize Ru–Ni/Al2O3 catalysts, which are then calcined and reduced at 800 °C. The results show that as the nickel loading increases, the syngas production increases. Promoting the catalyst with a small quantity of ruthenium significantly improves the plastic conversion into syngas. The dry reforming of polypropylene over 1Ru15Ni/Al2O3 catalyst resulted in the maximum syngas yield (159 mmolsyngas/gPP) at a 2:1 plastic to catalyst ratio. The catalytic dry reforming of plastics is promising for the production of synthesis gas.

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Identifying active site structure and unveiling corresponding reaction pathways are crucial issues to construct compatible reactive components in bifunctional catalysts for direct syngas conversion. Herein, the active surface structure and the reaction mechanism of syngas conversion to bridging intermediate methanol on ZnAl2O4 spinel oxide are systematically investigated by combining density functional theory calculations and microkinetic simulations. The hydroxylated oxygen-rich surfaces of ZnAl2O4 are demonstrated and their stabilities decreases as (100)-B-1/4H > (111)-B-3/8H > (110)-B-1/4H. Four reaction pathways differentiating in the adsorption site of CO and the participation style of H2 on these surfaces are kinetically compared. We reveal that ZnAl2O4(111) is the active surface for syngas conversion; CO bonding on O site is activated more readily in a stepwise way to CH2O and the concerted pathway is then followed for CH2O to methanol. On ZnAl2O4(100) and ZnAl2O4(110) surfaces, the Non-Horiuti-Polanyi pathway in which gaseous H2 reacting directly with CO or CH2O becomes kinetically more important. The Zn-O site of ZnAl2O4(111) is essential to dissociate H2 heterolytically and stabilize key intermediate CHO. We show that the reaction rate decreases with the CO conversion, and the simulated reaction rate (~13 s‚àí1) at 8% conversion agrees quite well with the experimental one (~20 s‚àí1) under the typical reaction conditions. The predicted activity plots with temperature and CO conversion highlight the driving essentiality of zeolite component in bifunctional catalysts for syngas conversion.

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Supported Pd catalysts with varied Pd loadings (x = 0.5 wt%, 2.0 wt%, 5.0 wt%, 7.5 wt%, 15.0 wt%) were prepared by the incipient wetness impregnation method using a ZnAl2O4 spinel support. We found that ZnAl2O4 supported Pd catalysts with low Pd loadings (e.g., 0.5 wt%) are very selective in syngas conversion to methanol and dimethyl-ether (DME). XRD and TEM characterization shows that, after reduction at 350 °C, PdZn β phase with Pd:Zn molar ratio of 1:1 is favored to form predominantly on the spinel support at relatively low Pd loadings, i.e. less than 5.0 wt%, while Pd-rich PdZn α alloy phase exists at Pd loadings above 5.0 wt%. A higher reduction temperature such as 500 °C can facilitate the transformation from PdZn α to PdZn β phase in those catalysts with high Pd loading. We further found that catalysts with predominant PdZn β phase are selective in the methanol and DME production from syngas, while the presence of PdZn α phase leads to the notable formation of alkanes byproducts, resulting in reduced methanol and DME selectivity. DME formation from dehydration of methanol depends on the acidity of catalysts, which was found to increase with Pd loading, probably due to the formation of isolated Al2O3 as a result of Zn migrating from ZnAl2O4 spinel phase to form the PdZn phases with Pd.

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Dry reforming of light hydrocarbons such as methane has gained interest due to the consumption of greenhouse gases like methane and CO2 and production of syngas (H2 and CO). Among light hydrocarbons, methane has gained attention due to it’s abundance. Besides, biogas, produced from biomass, leads to air pollution when flared or emitted; therefore, it can be converted to syngas through dry reforming of biogas. Additionally, dry reforming of ethanol and glycerol has been considered as renewable resource for syngas production. Further, dry reforming of biomass-derivatives is an alternative approach to produce syngas. Various catalysts have been used in these processes to produce syngas; however, rapid coke formation and catalyst deactivation are the major challenges during these reactions. Thus, many factors should be considered to design an efficient catalyst with high activity and low cost. Noble metal-based catalysts show great catalytic performance in these reactions, non– noble metal based catalysts are more useful due to their abundances and lower prices. To decrease the amount of coke deposition, bimetallic catalysts, and basic promoters have been highly recommended. Moreover, it has been reported that catalysts’ preparation method, reaction conditions, and type of reactor dramatically affect the catalytic performances. This review has evaluated the effects of catalysts, catalyst preparation materials and methods, process conditions, nature of the feedstock, and types of the reactor on dry reforming of methane.

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A novel process to produce a H2-rich syngas from a high moisture-containing agricultural waste digestate is proposed. This process combines the use of hydrothermal carbonization (HTC), dewatering, pyrolysis, and catalytic reforming. Due to the feature of the high moisture content in the digestate, the effect of the HTC and dewatering on the process performance is of interest, and four scenarios were considered. Furthermore, three pyrolytic temperatures were chosen to understand the effect of pyrolysis conditions on the produced H2-rich syngas. A life cycle assessment was conducted to investigate the environmental impact of the proposed process. Results show that the application of HTC technology, increases the process efficiency, produces less syngas from one ton of digestate, lowers the cumulative energy demand and the negative carbon emissions. When the dewatering technology is used, the syngas yield is promoted but the H2 concentration in the syngas is reduced. The H2 to CO molar ratio reaches the maximum value of 9.2 when using a 450 ÀöC pyrolysis temperature, by only using HTC. When the combining process of HTC and dewatering is used, it results in the highest process efficiency, but the smallest relative negative CO2 equivalent emissions by treating one ton of dry digestate.

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In this study, various weight fractions (0 wt% to 7 wt%) of multi-walled carbon nanotubes were incorporated onto woven kenaf/recycled polystyrene (MWCNT/KF/rPS) laminated composites. The MWCNT was incorporated using spraying technique and the flexural properties of the composites were investigated. The laminated composites were fabricated using hot press method. The flexural properties of the composite samples were evaluated by applying three-point bending test according to ASTM D 790–10 standard and the results were supported by morphological observation. It was found that the addition of MWCNT increased the flexural strength (σflex) and flexural modulus (Eflex) of MWCNT/KF/rPS laminated composites. Addition of 1 wt% MWCNT produced the optimum σflex and Eflex values of 17.22 MPa and 1053.71 MPa respectively, compared to other laminated composites. The morphological observation of the composites fracture surface showed that delamination failure occurred in all the MWCNT/KF/rPS laminated composites. The result of this study showed that MWCNT played a significant role on the flexural properties improvement of woven KF/ rPS laminated composites.

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As the constantly upgrading of electronic product, and the number of plastic shells of waste electronic products is also increasing sharply. Acrylonitrile-butadiene-styrene (ABS) and high impact-resistance polystyrene (HIPS) account for a large part, but ABS and HIPS not only have similar densities, but also have similar chemical properties, which make it difficult to separate ABS and HIPS. Therefore, the preparation of composite materials by blending waste ABS and waste HIPS is an important method to realize the high-value reuse of waste ABS and waste HIPS. In this work, d-glucose (d-Glucose) was used as a compatibilizing agent for the first time to modify recycling acrylonitrile-butadiene-styrene (rABS) and recycling high impact-resistance polystyrene (rHIPS) by melt blending. The d-Glucose has multiple hydroxyl groups, and it can react with the aging groups of butadiene in rABS/rHIPS to form ester groups, repairs broken molecular chains and improves compatibility between two phases to enhance the mechanical properties. The results show that the impact strength, tensile strength, flexural strength and storage modulus of the resulted rABS/rHIPS blend have been enhanced. When added the number of d-Glucose accounts for 5 wt% of the total components, the notched impact strength reaches 9.67 kJ/m2, which is 128% higher than that before modification. Compared with other researchers, not only the impact strength is greatly improved, but also the tensile strength and flexural strength are improved. The mechanisms for the enhancement is studied and discussed.

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Polystyrene was synthesized and applied as a template for fabricating hollow silica nanoparticles. Organic solvent and water were used as a solvent and an anti-solvent, respectively, to produce the polystyrene nanoparticles via. nanoprecipitation technique. The influence of precipitation method (one-shot or drop), solvent for dissolution of polystyrene, and concentration of polystyrene or CTAB linker on the diameter of polystyrene nanoparticles was investigated. The hollow silica nanoparticles were fabricated using the as-made polystyrene nanoparticles as a template with the help of CTAB linker. Polystyrene was recovered by the extraction of polystyrene@SiO2 composite with the tetrahydrofuran solvent, and the recovered polystyrene was re-used to make the polystyrene nanoparticles as a template for fabricating hollow silica nanoparticles. Our study can be applied for other types of polymeric materials as long as those polymeric materials form nanoparticles via. nanoprecipitation technique. In comparison with the polystyrene hard template prepared by emulsion polymerization, the size of polystyrene nanoparticles produced by the nanoprecipitation technique can be well-tuned by changing the polystyrene and linker concentrations.

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The construction sector is the most energy consuming one in the world, and it has a significant ecological impact. Indeed, concrete manufacturing overuses natural resources such as sand or gravel, and the need to use alternative building materials is urgent. Choosing adequate building materials takes an important part in the success of a high environmental quality project. This suggests using new alternative solutions, based on recycled materials or waste. However, their use being relatively recent, these materials properties are not widely known and there is lack of information concerning their hygrothermal and mechanical behavior. In this context, the present work aims then to highlight the experimental characterization of hygric, thermal, physical and mechanical properties of a recycled expanded polystyrene mortar, which is a relatively new building material, generally used for its thermal performances. Indeed, a complete characterization campaign was elaborated in this work, allowing a precise determination of the main properties of the material. The experimental characterization also included a usual cement paste made of the same cement as a reference material, in order to evaluate the polystyrene adding impact on the measured hygrothermal properties. Different methods of sorption isotherms determination were presented, and a better attention was devoted to the sorption hysteresis phenomenon characterization. The macroscopic hygrothermal properties, such as water vapor permeability, thermal conductivity and thermal capacity were also investigated function of the temperature and water content evolution. Mechanical strength was also determined, and SEM observations were performed to study the morphology of the material. Experimental results show that expanded polystyrene mortar exhibits a good thermal conductivity and thermal capacity, and a higher water vapor permeability. These results provide data for better forecast on the prediction of the hygrothermal and mechanical behavior of such material.

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In this work, an environmentally friendly and value-added technique was employed to obtain polystyrene (PS) nanoparticles from expanded polystyrene (EPS) waste. The waste was dissolved in ethyl acetate and nanoprecipitated in ethyl alcohol, which are green and renewable solvents. The EPS concentration, stirring speed and solvent/non-solvent ratio (S/N) were evaluated in obtaining nanoparticles. The precipitated nanomaterial was characterized by Dynamic Light Scattering (DLS), Field Emission Gun Scanning Electron Microscopy (FEG-SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TG), Differential Scanning Calorimetry (DSC) and Gel Permeation Chromatography (GPC). It was verified that the smaller nanoparticles were obtained with lower PS concentration (1 wt.%), greater stirring speed (2500 RPM), and higher S/N ratio (1:30). The observed morphology was spherical and no change in the chemical structure of the sample was verified, the glass transition temperature (Tg) was similar (101 °C) and there was no change in the crystalline structure of the sample. Regarding the efficiency and sustainability of the process, all used solvents can be easily recovered by distillation process.

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5-Hydroxymethylfurfural (5-HMF) is one of the compounds, which has attracted a lot of attention due to its multi-functional nature and many applications in the industry. In this experimental study, 5-HMF has been synthesized using a polystyrene-supported Brønsted acid ionic liquid catalyst. This heterogonous catalyst has been synthesized via the decoration of 5-amino-1H-tetrazole-bonded sulfonic acid onto the surface of chloromethylated polystyrene (PS-Tet-SO3H). The prepared PS-Tet-SO3H is was characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry–differential scanning calorimetry (TG-DSC), and Scanning electron microscopy (SEM). PS-Tet-SO3H catalyst for has then been used in the synthesis of 5-HMF from fructose via an acid hydrolysis reaction. Finally, the prepared PS-Tet-SO3H can be recycled and reused for 4 cycles with no significant loss of performance.

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We report the use of flexible photocatalytic composites for the degradation of the 4-chlorophenol (4-CP) contaminant from the drinking water. These composites were made of recycled bags (RBag) or recycled polystyrene (RPS) from food packaging and CuS/TiO2 (CuST) nanoparticles. The structural and morphological characterization indicate that the CuST nanoparticles have an average size of size of 41 ± 2 nm and present a mixture of anatase/brookite phases. The CuS/TiO2 powders were dispersed in water contaminated with 4-CP and produced a maximum degradation percentage of 92% after 4 h under UV–VIS irradiation. In the case of the RBag-CuST and RPS-CuST composites, they floated on the contaminated water and produced maximum degradation percentages of 89 and 100%, respectively. After 3 cycles of continuous use, the degradation percentages decreased from 92 to 84%, from 89 to 81% and from 100 to 95% for the CuS/TiO2 powders, RPS-CuST and RBag-CuST composites, respectively. Scavenger experiments were carried out and found that the main oxidizing agent for the degradation of 4-CP was the OH radical. The production of such radical decreased in the order RBag-CuST > CuS/TiO2-powders > RPS-CuST. The RBag-CuST was more efficient for the degradation of 4-CP because its production of oxidizing agents was the highest and it contained more oxygen vacancies defects (electron trapping centers) than the other photocatalysts, which was confirmed by the absorbance measurements. In general, we demonstrated that making flexible photocatalytic materials from recycled bags/polystyrene is a feasible and low cost option to remove pesticide contaminants from the drinking water. Those composites can be removed manually from the cleaned water, which is not possible with the conventional photocatalytic powders.

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In recent decades, there has been a significant rise in the production and consumption of plastics and polystyrene products (notably Expanded Polystyrene or EPS), and the reuse of their waste nowadays, due to their pollution potentials, has come to the forefront of attention. In this paper, new green building insulation is offered and examined, combining recycled plastic layers and EPS boards. The waste plastic bags turned into plastic sheets during the simple recycling process, and a monolithic EPS was divided into several boards with different thicknesses. Then, the recycled plastic bags were placed between EPS boards. Two composites of plastic sheets and EPS boards were prepared. The first composite consists of three layers (two layers of EPS with a thickness of 20 mm each, and a 10-millimeter plastic layer consisting of 36 recycled plastic bags). The second composite includes five layers (three layers of foam with a thickness of 10 mm each, and two layers of plastic paper, each consisting of 24 recycled plastic bags). All samples were similar in dimension, thickness, foam density, and type. The two new composites were then compared with the control sample in compressive strength, water absorption, and flame spread test. Even though a dramatic reduction of compressive strength has been observed, the results reveal the suitability of both three- and five-layer composites, which considerably improves fire and water resistance compared to the control sample.

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Cement-polymer composites were developed to enhance the mechanical durability and reduce the porosity of cement, and to acquire a value-added end product useful for many applications in the construction sector. The novel product should be stable during exposure to various challenging environments, e.g., water of different quality, origin, and dissolved ions. The present work evaluated the impact of immersing the new cement-polymer composites (CPs), containing different fractions of recycled waste polystyrene foam, in plain, ground and sea water on the composites’ properties. After 420 days of immersion in all studied types of water, the obtained CPs showed acceptable compressive strength values (more than 30 MPa); in addition, corrosion resistance coefficients (K) were increased more than unity in comparison to non-immersed samples. Moreover, this study also determined alterations of internal architecture of composite specimens cured for 28 days after immersion for up to 420 days in water of different composition. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used for these studies.

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There is international interest to increase recycling rates of expanded polystyrene foam (EPS). Extensive use of brominated flame retardants (BFRs), however, presents a hinder to this. If uncontrolled, hazardous BFRs could persist in recycled EPS leading to new exposure routes, including in materials such as EPS packaging where no flame retardants are required. This study looked at EPS foam collected from Norwegian Municipal Waste Sorting Facilities, visually sorted as "white EPS foam", mostly derived from packaging. Bromine was analysed by X-ray fluorescence (XRF), and selected BFRs including hexabromocyclododecane (HBCDD) were analysed by targeted gas chromatography-mass spectrometry analysis. Results were compared with EU and UNEP low persistent organic pollutant concentration limits (LPCLs). One out of 120 samples contained HBCDD over established LPCLs, likely attributable to missorted insulation EPS. Further, no false negatives occurred, as all samples in which target BFRs were quantified had XRF-detectable bromine. Visual sorting of white EPS packaging foam, with the use of XRF in uncertain cases has the potential of minimizing hazardous BFRs in recycled EPS. The context of national sorting infrastructure and compliance should be a central feature of future studies investigating how BFRs or other hazardous substances enter the global circular economy.

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In the present study, sawdust/recycled expanded polystyrene (SD/rEPS) composite was manufactured to be used as sound-absorbing materials. To achieve this aim, SD/rEPS composites containing different loading level (0, 20, 40, 60 and 80 wt percent) of SD were prepared. The addition of 20% SD exhibited better dispersion within recycled expanded polystyrene (rEPS) matrix than higher loading level of SD, as indicated from scanning electron microscope. Consequently, the tensile strength and flexural strength were improved by 16.7% and 14.1%, respectively. The higher loading level of SD displayed aggregation within rEPS matrix which reflected negatively on the mechanical properties. Young's and shear modulus varied from between 0.41 and 1.23 GPa for 0–60% SD. Longitudinal and bulk modulus recorded a reduction from 0.55 to 1.26 GPa with increasing SD. Sound absorption improved with increasing SD loading level. Nonperforated samples of 60% SD and 80% SD had high absorption at 500 and 315 Hz where the sound absorption coefficient (SAC) was about 0.85 and 0.75, respectively. The perforated sample of 80% SD exhibited the highest sound absorbing at low frequencies 315 Hz (SAC~0.9). The biodegradability of the prepared composites was investigated using burial in soil for 90 days where the weight loss increased linearly with increasing SD within the rEPS matrix.

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With the rapid development of the fifth-generation mobile communication, stringent requirements have been put forward for the dielectric properties of polymer-based copper-clad laminates. However, thermally and mechanically robust materials with low dielectric loss (Dr) are very scarce. Herein, we propose a simple method to prepare cyclic polyolefin (COC)/polystyrene vitrimers (PSVMs) from semi-interpenetrating polymer networks with low Dr. The topological rearrangement of PSVMs caused by the transesterification of nitrogen-coordinating cyclic boronic ester (NCB) linkages under heat helped uniformly disperse the COC in the PSVM. As a result, the COC-PSVM and its quartz glass fiber reinforced COC-PSVM composites exhibited excellent thermal, mechanical, and dielectric properties. Specifically, the dynamic reversibility of the NCB linkages under heat facilitated the complete recovery of the COC-PSVM composites. This study provides a new strategy for the preparation of resin matrix with low Dr for printed circuit boards, which is conductive to reducing the environmental pollution from e-waste.

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Recently streamlining wood waste production and promote their recovery and recycling have been popularized with the sustainable utilization of the waste generated in the saw mill to promote sound, sustainable and healthy wood waste management practices. Herein, we report the development of polymer composite from the saw dust as a reinforced filler on the natural non-edible cotton seed oil resin as feedstock amalgamated with the styrene monomer. The prepared virgin polymer saw dust (VPSD) composite holds light weight, low cost, easy handling and storage, enhanced mechanical strength, low energy production, eco-friendliness, renewability and sustainable waste management. The reinforced polymer composite material was characterized by spectroscopic and microscopic techniques. The thermal studies of the as-prepared composite shows the extended thermal degradation due to the blending of saw dust into the polymeric process and its mechanical study confirms the enhanced stiffness due to the wooden dust. Due to the significant property obtained by reinforcing the saw dust in the natural resin matrix, the process could be used to extend the development of many polymeric feedstocks as a part of sustainable waste management process.

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Thermal insulations help to reduce household energy demand and extend the periods of thermal comfort generated by heating and cooling systems. Conventional isolations may not be economically accessible to all social sectors, despite their benefits. This paper presents and evaluates an alternative low-cost insulating material and its variants, based on the mechanical reuse of expanded polystyrene (EPS) waste packaging, cementitious binder, plastic additives, and water. These materials show comparable performance to commercially available insulations (thermal conductivity range 0.0603–0.0706 W/m K) and provide an environmentally-safe and cost effective alternatives for house isolation for the low income population living in settlements worldwide.

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Polystyrene-based products are widely used in industrial and daily activities, but their subsequent disposal can negatively affect the environment. This work focuses on reducing polystyrene waste into useful material. A waste-derived polystyrene sorbent (WDPS) was fabricated and successfully applied to determine bisphenol-A in canned beverages. High-performance liquid chromatography with a diode-array detection (HPLC-DAD) was applied to quantify bisphenol-A. Good linearity at a concentration range of 2.5–50 μg L-1 was achieved. The limit of detection was 0.93 ± 0.02 μg L-1. Good precision (RSDs < 1.6 %, 4 concentrations, n = 6) in spiked coconut juice samples were obtained. The contamination of BPA in canned beverage samples were found in the range of 6.3 ± 0.2 μg L-1 to 27.0 ± 1.0 μg L-1 with recoveries in the range of 70.4 ± 1.6 % to 82.4 ± 0.4 %. This proposed method also offers reduced polystyrene waste, reuse as a sorbent, and recycling after use.

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The cross-linked polystyrene (PS) are commonly used plastic materials, however, the greater brittleness and the difficulties in recycling severely limit their applications. In this work, we provide a new strategy for the crosslinking of PS based on the nitrogen-coordinating cyclic boronic ester (NCB) linkages. PS vitrimers are synthesized from PS with hydroxyl groups and isocyanate-terminated NCB oligomer. Incorporating NCB linkages cangreatly improve the solvent resistance, thermal stability and mechanical properties of PS without sacrificing its dielectric properties. PS vitrimers exhibit rapid stress relaxation and improved creep resistance due to the stable NCB linkages. PS vitrimers were able to withstand multiple reprocessing cycles via the exchange reactions of NCB linkages without catalyst. The recycled PS vitrimers were shown to regain the structural integrity, mechanical strength and dielectric properties as the original. The glass fibre reinforced PS vitrimer composites were prepared to explore the application in copper clad manufacture, which showed good mechanical properties and can be conveniently recycled to resin solution and clean glass fibre. This work provides a new strategy for the development of the green dielectric polymer materials for copper clad laminates, and may serve as a guide for rational design of dynamic materials based on general-purpose plastics.

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This study investigated recycling of expanded polystyrene (EPS) waste in a closed-loop design using the dissolution technique. The objective is to dissolve a maximum rate of EPS waste in styrene (its monomer), followed by suspension polymerization of this solution to incorporate the monomer (the solvent) in the polymer chain to avoid the need to separate the polymer and the solvent. The study evaluated the best operating conditions for these procedures, which resulted in 92% g·g−1 of particles at the appropriate size for expansion (425–1400 μm). Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were conducted to determine the chemical, thermal and rheological properties of the recycled polymers and to compare them with standard polymer, demonstrating that the recycled material kept its chemical, thermal, and rheological properties. This novel closed-loop technology has strong potential to produce recycled EPS with good properties and, if well established, will allow EPS recycling without the formation of secondary waste, in keeping with the principles of sustainable development and circular economy. A brief analysis of this process revealed a strong reduction in environmental impacts and suggests its economic viability, considering the demand for and market value of EPS and the investment required to produce it in a recycling process that could be amortized in a short period.

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In recent years, the production of disposable plastic products is increasing day by day and resulting in global growing concern that it poses to the environment. Microorganisms hardly resolve these types of plastic wastes; therefore, recycling the value-added materials is very important. Recycling and reusing plastic wastes to produce superhydrophobic nanofibers for atmospheric clean water production could be a partial solution to address the environmental issues. Herein, superhydrophobic-hydrophilic nanocomposites fibers were fabricated using recycled expanded polystyrene (REPS) as inspired by the fog-harvesting capability of Stenocara beetles in the Namib Desert. The REPS were electrospun with various proportions of titanium dioxide (TiO2) nanoparticles and aluminum (Al) microparticles. The fiber morphology, surface hydrophobicity, thermal properties, and fog water-harvesting performance of the nanocomposite fibers were studied. The as-prepared nanocomposites fibers with a 10% inclusion of combined micro-and nanoparticles exhibit superhydrophobic properties with a water contact angle of 157° and daily water productivity of more than 1.35 liter/m2 of nanocomposites. The expenses of materials to produce such nanocomposites needed to supply the minimum daily water consumption for a two-member household (6 liters) are only US$2.67. These nanocomposites are inexpensive, reusable, do not require additional energy consumption, and are particularly suitable for producing clean water in arid areas. This study offers a new technology for the mass production of clean water through nanotechnology at a relatively low cost.

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In recent times, a substantial part of the generated solid waste all over the world are plastic-related waste with wide ranges of serious environmental and public health consequences. This study investigates the beneficial use of recycled high impact polystyrene (HIPS) and low-density polyethylene (LDPE) plastic wastes in cement-based composites for production of high strength lightweight concrete. The HIPS and LDPE plastic wastes were recycled into plastic granules of about 2‚ÄØmm particle sizes and was used to partially substitute the sand in the concrete mixes at varied percentage levels of 0, 10, 30 and 50% by weight using a mixture proportion of 1:1.5:3 (cement: m-sand: coarse aggregate) at water-cement (w/c) ratio of 0.5 with a target characteristic strength of 30‚ÄØN/mm2 at 28‚ÄØdays. The material characteristics were defined, and concrete cube samples of size 100‚ÄØmm were cast and tested in the fresh and hardened state. Test results indicate a decrease in the workability, density and compressive strength as the quantities of the recycled waste plastic granules increases. Implications of these results show the possibility of using recycled plastic granules from both high impact polystyrene and low-density polyethylene plastic wastes at optimum of 10% for producing lightweight-high strength concrete that is closely similar in strength to lightweight concrete produce with conventional materials.

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Radioactive sulfate wastes are generated from boiling water reactors (BWRs) and should be immobilized before their disposing to avoid the back release of their hazardous components under the impact of water flooding incident in the disposal site, which gives rise of secondary contamination at the surrounding area. A cement-polymer composite formulated from recycled post-consumer polystyrene foam waste and Portland cement was proposed as an incorporating matrix for solidification/stabilization (S/S) of sulfate waste simulate in laboratory scale experiments. To imitate a water-flooding incident, the reached solidified waste form was completely immersed in three types of water, namely, tap-, ground-, and seawater for increasing periods up to 420‚ÄØdays. Compressive strength, porosity and mass change of the solidified waste samples were evaluated at the end of various immersion periods. Besides, FT-IR, XRD, SEM with EDX analyses were performed to follow the internal changes of the product post the immersion. Based on the data obtained, it could be concluded that the comparative stability of the nominated composite under the impact of water flooding incident candidates it as an acceptable matrix for immobilizing the radioactive sulfate wastes. In addition to its stability, the formulated composite have the advantage of upgrading post-consumer non-biodegradable polystyrene foam waste, therefore, thus introducing a sustainable technique and saving landfill area by using significant amounts of one of the major municipal solid wastes.

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