Waste Blends Research Articles

Peranan medan magnet dan campuran etanol-biodiesel minyak jelantah pada pembakaran droplet terhadap perilaku api dan emisi gas buang

Petroleum reserves are increasingly depleting, causing a scarcity of petroleum fuel caused by the rapid progress of transportation and the manufacturing industry. This condition forces researchers to search for and develop new renewable energy source. The purpose of research is to understanding and determines role of north-south (U-S) and south-south (S-S) magnetic fields to blend waste cooking oil biodiesel-ethanol on flame evolution, flue gas emissions, and temperature during droplet combustion. Waste cooking oil biodiesel and ethanol were used in this research by adding variations in the direction of repulsive and attractive magnetic fields with an intensity of 11000 gauss. Diameter of droplets tested was 0.3 mm and was placed on a type K thermocouple wire with diameter of 0.1 mm. This research found the role of attractive magnetic field (U-S) in blend waste cooking oil biodiesel-ethanol 20% to produce the shortest flame evolution of 704 ms, lowest CO of 165 ppm, and highest temperature of 828.5 oC. This happens because ethanol has a low flash point and large oxygen content, causing the combustion reaction to occur rapidly. The attractive of magnetic field (U-S) plays a role on attracting oxygen around flame to enter combustion reaction, while the H2O resulting from combustion is pumped out of flame.

Investigation on the mechanical properties of wood-plastic composites for the application of ceiling panels

Wood-plastic composites are relatively novel composite materials that consist of a blend of wood flour waste with high-density polyethylene and polypropylene plastic waste, designed for use in ceiling applications. Various samples were produced using different ratios from the total weight, including 20:80, 30:70, and 40:60, with sieve sizes of 0.425 mm, 1.18 mm, and 2 mm. The composites were created by melting plastics and sawdust at a temperature of 1800c utilizing the hot-press moldings technique employing diverse formulations. The properties of sample composites were analyzed experimentally based on ASTM standards to investigate water absorption levels as well as flexural strength, impact resistance hardness along with surface morphology via the design of experiments. This research study indicates that nine composite formulations consisting of HDPE and PP plastics combined with wood flour can produce favorable physio-mechanical properties. Among these various combination specimens tested in this study FS3/FC30N exhibited excellent physio-mechanical properties; including desirable values such as water absorption level at 5.5103%, flexural strength at 61.12 Mpa, impact resistance measuring 33.45 J cm−2, and hardness rating up to 80 RHB. Thus it is highly recommended for use in chipboard ceiling panel applications due to its potential benefits.

Experimental analysis of the effects of feedstock composition on the plastic and biomass Co-gasification process

Co-gasification is a feasible approach to manage fast-growing plastic and biomass waste issues. The current work examines air gasification of plastic waste blending with biomass. The influence of plastic-type and biomass characteristics on product distribution under the same operating condition was studied. Ethylene-vinyl acetate, high-density polyethylene, and polypropylene were the investigated plastics while the biomass materials considered were pine sawdust (PS), used ground coffee (UGC), and wheat straw (WS) are compared. Additionally, co-gasification and thermogravimetric analyses (TGA) of plastic and individual biomass components, namely, cellulose, hemicellulose, and lignin, were conducted to identify the nature of the synergy arising from plastic and biomass integration. Similarities in the chemical structure and composition of the investigated plastics resulted in the type of plastic marginally influencing product distribution. The gas composition included 4.6 vol% CH4, 37.5 % CO2, 5.3 % CnHm, 42 % CO, and 10.8 % H2, with yields of 5.9 wt% char, 39.5 wt% gas, and 54.8 wt% tar. Conversely, the type of biomass had a substantial effect on both gas composition and product yields. WS and UGC, characterized by higher hemicellulose and lignin content, generated more hydrogen with 14.4 and 13.3 vol%, respectively, and exhibited lower tar content (45.7 and 47.8 wt%) compared to PS, which has a higher cellulose content and yielded 54.8 wt% tar. During EVA/cellulose co-gasification, the predominant gases produced are CO and CO2, with H2 concentration of 7.2 vol%. In contrast, co-gasification of EVA/xylan and EVA/lignin yields 13.5 and 19.9 vol% hydrogen, respectively. Interactions and synergism between the plastic and biomass were found to be more intensified when the biomass contained greater proportions of cellulose and lignin. Co-gasification and TGA analyses indicated that plastic/cellulose and plastic/lignin interactions in the gas and solid phases (volatile-volatile and volatile-char interactions) and plastic/xylan interactions in the gas phase (volatile-volatile interactions) were significant. Modeling the predictability of the output data revealed that if interactions between the plastic and biomass components are accounted for, the co-gasification results are predictable with a credible accuracy for all biomass types. The predictability model offers a practical approach for selecting an appropriate co-gasification feedstock combination to give a targeted process performance.

Production of biodiesel from non-edible waste palm oil and sterculia foetida using microwave irradiation

Abstract The environmental damage stemming from traditional diesel begins during crude oil extraction and persists throughout its usage. The burning of fossil fuels has further deteriorate the environmental effect and added to global warming by emitting harmful substances. Moreover, the reduction of finite fossil fuel reserves due to widespread extraction has made the adoption of renewable resources essential. Given these considerations, biodiesel emerges as a highly promising alternative to conventional diesel due to its environmentally beneficial nature, renewable source, and economic feasibility. In this study, biodiesel was prepared by a microwave reactor in the presence of potassium methoxide using blended waste palm oil and sterculia foetida. The effects of raw materials characteristics on transesterification products were studied. The studied process parameters were methanol/oil ratio, microwave temperature, catalyst concentration, reaction time, and stirring speed. The optimal yield with 98.5% FAME content was obtained at a methanol/oil ratio of 60 vol. %, microwave temperature of 120 °C, catalyst concentration of 0.3 wt.%, and 3 min reaction time, and stirring speed of 500 rpm. The potassium methoxide was used to catalyse the transesterification process. The physicochemical properties and the fatty acid methyl ester composition were discussed thoroughly. The flash point of biodiesel, at 157.5°C, exceeds that of diesel fuel by more than two times. The cetane index is 59.5 which is higher than diesel (49.6). The biodiesel’s fuel properties conformed to the requirements of both ASTM D6751 and EN 14214. High biodiesel conversion and low sulphur content show that waste palm oil and sterculia foetida are sustainable and economical feedstocks that produce clean fuel to aid the feasibility of the energy transition of the global energy sector. In addition, the selection of synthesis approaches can be further explored for potential catalysts to ensure eco-green biodiesel’s sustainability with minimised.

Antioxidant and cytotoxic activities of protein hydrolysates from shrimp shell wastes, germinated soybean and pigeon pea flour blends: A mixture response surface methodology approach

Cancer has high prevalence rate and mortality with conventional chemotherapy and other management protocols being both expensive and inaccessible especially in low/medium income countries (LMIC). Sourcing alternative cheaper and easily accessible treatment from blends of antioxidants sources can reduce the burden of cancer on patients. This work therefore seeks to produce a blend from the protein hydrolysates of shrimp shell waste, germinated soybean and germinated pigeon pea which not only has high antioxidant activity but also can inhibit cervical cancer cell proliferation. In vitro antioxidant and cytotoxic activities of the mixtures of germinated pigeon pea, germinated soybean, and shrimp shell waste hydrolysates were evaluated using the mixture response surface methodology (MRSM). Fourteen blends were obtained using the simplex centroid design. Total phenolic content (TPC), 2, 2-Diphenyl-1-Picrylhydrazyl (DPPH) and % cytotoxicity of the samples were analysed. Numerical optimization was conducted with the goal of simultaneously maximizing the DPPH scavenging activity and TPC while minimizing % cytotoxicity. The optimized blend consisted of 91.06 % pigeon pea, 8.94 % shrimp shell waste and 0 % soybean. The predicted responses obtained were 74.28 % DPPH scavenging activity, 39.6 GAE mg/dL TPC and 21 % cytotoxicity. The IC50 values for the optimized blend and a standard chemotherapeutic drug were 0.260 mmol/mL and 0.013 mmol / mL respectively. This in vitro study revealed that the pigeon pea - shrimp shell waste blend, as generated by MRSM, was comparable to a standard anticarcinogenic drug with respect to potency. Keywords: pigeon pea, soybean, hydrolysates, shrimp shell waste, cytotoxicity, antioxidants, DPPH

Enhancing biomethanation performance through co-digestion of diverse organic wastes: a comprehensive study on substrate optimization, inoculum selection, and microbial community analysis.

A blend of organic municipal solid waste, slaughterhouse waste, fecal sludge, and landfill leachate was selected in different mixing ratios to formulate the best substrate mixture for biomethanation. Individual substrates were characterized, and the mixing ratio was optimized with the help of a response surface methodology tool to a value of 1:1:1:1 (with a C/N ratio of 28±0.769 and total volatile fatty acid (VFA) concentration of 2500±10.53 mg/L) to improve the overall biomethanation. The optimized blend (C/N ratio: 28.6, VFA: 2538 mg/L) was characterized for physicochemical, biological, and microbial properties and subjected to anaerobic digestion in lab-scale reactors of 1000 mL capacity with and without the addition of inoculum. The biogas yield of individual substrates and blends was ascertained separately. The observed cumulative biogas yield over 21 days from the non-inoculated substrates varied between 142±1.95 mL (24.6±0.3 ml/gVS) and 1974.5±21.72 mL (270.4±3.1 ml/gVS). In comparison, the addition of external inoculation at a 5% rate (w/w) of the substrate uplifted the minimum and maximum cumulative gas yield values to 203±9.9 mL (35.0±1.6 mL/gVS) and 3394±13.4 mL (315.3±1.2 mL/gVS), respectively. The inoculum procured from the Defence Research and Development Organisation (DRDO) was screened in advance, considering factors such as maximizing VFA production and consumption rate, biogas yield, and digestate quality. A similar outcome regarding biogas yield and digestate quality was observed for the equivalent blend. The cumulative gas yield increased from 2673±14.5 mL (373.7±2.2 mL/gVS) to 4284±111.02 mL (391.47±20.02 mL/gVS) over 21 days post-application of a similar dosage of DRDO inoculum. The 16S rRNA genomic analysis revealed that the predominant bacterial population belonged to the phylum Firmicutes, with the majority falling within the orders Clostridiales and Lactobacillales. Ultimately, the study advocates the potential of the blend mentioned above for biomethanation and concomitant enrichment of both biogas yield and digestate quality.

Energy recovery from sewage sludge waste blends: Detailed characteristics of pyrolytic oil and gas

Using waste as an alternative energy source may partially replace fossil fuels. In this paper, energy recovery from waste blends (sewage sludge (SS), polyethylene (LDPE) and polypropylene (PP), paper rejects (PR), and waste tyres) was tested through laboratory-scale co-pyrolysis. For each co-pyrolysis test, 7 l of waste blend in different ratios were used. The results of pyrolytic oil and gas analyses show valuable compounds and chemical materials recovered. The detailed analyses show the effects of co-pyrolysis parameters, especially the ratios of waste blends with respect to the process temperature of 600°C, on the pyrolytic gas and oil. The highest volumes of gas (0.66 m3) and oil (699 ml) were obtained from sample 5_8 (PES:SS:PR). Waste blend 15_1 (LDPE:SS) had the highest gross calorific value (GCV) of 43.82 MJ/m3 in gas, and had the highest proportion of flammable components (46.31% of methane). Sample 5_8 had the highest calorific value in pyrolytic oil (45 MJ/kg) and sample 5_3 had the lowest (28.113 MJ/kg), which is comparable to coal. High-quality pyrolytic gas and oil were obtained with average GCV of 44 MJ/m3 and 40 MJ/kg respectively, where the average GCV of the most calorific fossil fuels is 43.6 MJ/kg in crude oil and 34 MJ/m3 in natural gas. We conclude that co-pyrolysis of sewage sludge and waste is a convenient and simple method of waste disposal under a synergetic effect of efficient waste management, energy production, and reduction of dependence on fossil fuels.

The role of nanoclay in processing immiscible polypropylene and poly (ethylene terephthalate) waste blends using twin screw extrusion

Polypropylene and poly(ethylene terephthalate) waste were blended with different types of nanoclay (cloisite Na+, cloisite 20A and CT4270) to understand the role of nanoclay in immiscible polymer blends. The blend morphology was investigated using scanning electron microscopy, the dispersion of the nanoclay was characterized using wide angle x-ray diffraction (WAXD) and rheology. WAXD results showed partial exfoliation for cloisite Na+ and intercalation for cloisite 20A and CT4270. It was predicted that cloisite Na + settled in the PET phase while cloisite 20A settled at the interface of PP and PET. Morphology analysis showed that increasing the concentration of nanoclay in the blend decreased the droplet size. The nanoclay was shown to inhibit coalescence of the droplets causing a decrease due to its rigidity.

Unveiling a Technosol-based remediation approach for enhancing plant growth in an iron-rich acidic mine soil from the Rio Tinto Mars analog site

This paper explores the potential of Technosols made from non-hazardous industrial wastes as a sustainable solution for highly acidic iron-rich soils at the Rio Tinto mining site (Spain), a terrestrial Mars analog. These mine soils exhibit extreme acidity (pHH2O = 2.1–3.0), low nutrient availability (non-acid cation saturation < 20 %), and high levels of Pb (3420 mg kg−1), Cu (504 mg kg−1), Zn (415 mg kg−1), and As (319 mg kg−1), hindering plant growth and ecosystem restoration. To address these challenges, the study systematically analyzed selected waste materials, formulated them into Technosols, and conducted a four-month pot trial to evaluate the growth of Brassica juncea under greenhouse conditions. Technosols were tailored by adding varying weight percentages of waste amendments into the mine Technosol, specifically 10 %, 25 %, and 50 %. The waste amendments comprised a blend of organic waste (water clarification sludge, WCS) and inorganic wastes (white steel slag, WSS; and furnace iron slag, FIS). The formulations included: (T0) exclusively mine Technosol (control); (T1) 60 % WCS + 40 % WSS; (T2) 60 % WCS + 40 % FIS; and (T3) 50 % WCS + 16.66 % WSS + 33.33 % FIS. The analyses covered leachate quality, soil pore water chemistry, and plant response (germination and survival rates, plant height, and leaf number). Results revealed a significant reduction in leachable contaminant concentrations, with Pb (26.16 mg kg−1), Zn (4.94 mg kg−1), and Cu (2.29 mg kg−1) dropping to negligible levels and shifting towards less toxic species. These changes improved soil conditions, promoting seed germination and seedling growth. Among the formulations tested, Technosol T1 showed promise in overcoming mine soil limitations, enhancing plant adaptation, buffering against acidification, and stabilizing contaminants through precipitation and adsorption mechanisms. The paper stresses the importance of tailoring waste amendments to specific soil conditions, and highlights the broader implications of the Technosol approach, such as waste valorization, soil stabilization, and insights for Brassica juncea growth in extreme environments, including Martian soil simulants.

Enhanced Biochar Production via Co-Pyrolysis of Biomass Residual with Plastic Waste after Recycling Process

Biomass pyrolysis for oil production results in biochar byproduct, whose characteristics can be improved by the reuse of waste plastics. While the plastic recycling process leads to a large amount of plastic waste that cannot be reused, this underutilized feedstock holds the potential for coprocessing with biomass, thereby increasing the likelihood of producing valuable biochar products. This study sought to evaluate how the inclusion of plastic waste influences the pyrolysis of biomass residue. To this end, sawdust and hardwood biomass were chosen as materials to investigate how the presence of plastics might alter the properties of the resulting chars. Synergies were observed among the biomass components, particularly in samples with higher lignin content from hardwood biomass, which resulted in increased biochar yields. The results showed that a 20% blend of plastic waste with wood at 300°C produced a solid char with a yield of 40% by weight. Co-pyrolysis of the biochar derived from blends of 20 wt. % PP with both sawdust and hardwood resulted in significant enhancement of various properties of the resulting biochar, including surface area, carbon content, hydrophobicity, and aromaticity. This enhancement had a favorable effect on the carbon content and calorific values of the biochar. These enhanced properties significantly contributed to the biochar’s capacity for sorbing substances like various heavy metals. It can be proved that this result showed the importance of the energy content of biochar and its potential use for renewable applications. The beneficial combined effect seen in the plastic blends can be credited to the interaction between the biomass and polymer components, resulting in the production of fewer volatile products at higher temperatures. It can be suggested that biochar from biowaste and plastic waste not only reduces environmental impact but also converts it into a valuable and eco-friendly product.

Slagging Fouling Prediction of Wood Waste Blending as Co-Firing Fuel for Northern Java Power Plant

Indonesia has implemented co-firing as a step for renewable energy utilization. Power plants in Northern Java could utilize wood waste from surrounding wood processing industries as co-firing fuel. In this study, wood waste with high value of ash fusion and stock coals of power plant were used as samples. Blended coals from stock coals are selected based on calorific value, slagging-fouling-abrasion prediction, and softening temperature prediction. Selected blended coals are mixed with wood waste in percentage of 10 wt% to 90 wt% to produce co-firing fuel which then predicted for risk tendency of slagging-fouling-abrasion by theoretical indices. The result shows that the addition of wood biomass increases the slagging, fouling, and abrasion tendency. In this study, addition of 20-30 wt% wood waste to blended coals can still be recommended with the medium risk of slagging-fouling and low risk of abrasion tendency.

Influence of Blended Waste Cooking Oils on the Sustainable Asphalt Rejuvenation Considering Secondary Aging

Influence of Blended Waste Cooking Oils on the Sustainable Asphalt Rejuvenation Considering Secondary Aging

Assessing the effects of agricultural waste returning on soil moisture characteristics

AbstractAgricultural waste is an emerging and promising resource due to its abundant organic compounds and high water‐holding capacity. It plays a crucial role in improving soil water use efficiency and contributing to sustainable agricultural development. This study aimed to investigate the impact of returning agricultural waste on soil moisture characteristics. Different volume ratios (4:5:1:0, 3:5:1:1, 2:5:1:2, 1:5:1:3, and 0:5:1:4) of agricultural waste blend (AWB) consisting of cattle manure, yellow loam soil, wheat straw, and distiller's grains were examined, and the water‐holding performance of the five AWB ratios under various suction forces was compared. The analysis confirmed the suitability of the Van Genuchten‐Mualem model for fitting soil moisture characteristic curves at different ratios. The study also examined the influences of AWB ratios on soil‐specific water capacity, hydraulic parameters, and equivalent pore size. The results showed that agricultural waste effectively increased soil‐specific water capacity, available water content, soil WHC(Water‐holding capacity), and soil pore count. Furthermore, reducing cattle manure and increasing distiller's grains enhanced these effects. For instance, when the AWB ratio was 0:5:1:4, soil‐specific water capacity increased by 47.7%, while field WHC and available water content increased by 9.9% and 3.8%, respectively. Additionally, the number of extremely small and small pores increased by 1.4% and 0.77%, respectively. These findings provide valuable theoretical guidance for agricultural waste treatment and improving soil WHC. Based on the results, it is recommended to increase the proportion of distiller's grains and reduce organic fertilizer when using agricultural waste for improving soil WHC.

Process optimization for blended waste frying oil in biodiesel production using CaO derived from African periwinkle shell catalyst through response surface methodology

Biodiesel is one of the renewable energy alternatives for fossil fuel because of its biodegradability, no toxicity, and environmentally friendly nature. Investigations have been made on transesterifying blended waste frying oil (BWFO) into biodiesel using African periwinkle shells (APS) heterogeneous catalyst. The BWFO, a mixture of 60:40 groundnut oil and waste palm oil, usually causes serious environmental problems when indiscriminately disposed. After being calcined, the non-activated APS (RAPS) was further sulphonated to create an acid-activated APS (AAPSA) catalyst. Scanning electron microscopy (SEM), X-ray fluorescence (XRF), the Brunauer-Emmett-Teller method (BET), and other techniques were used to characterize the produced RAPS and AAPSA. Gas chromatography-mass spectrometry (GC-MS) and Fourier-Transform Infrared Spectroscopy (FTIR) were used to evaluate the produced biodiesel. Besides, a series of physiochemical properties including acid value, density, kinetic viscosity, flash point, cloud point, pour point, and other fuel properties of produced BWFO, were evaluated using ASTM standard methods. The central composite design (CCD) of the response surface methodology (RSM) was utilized for modeling and process optimization of biodiesel production from BWFO.The characterization results revealed that CaO (62.07 %) is the main constituent of AAPSA. The RPSA's pore volume and BET surface area were 0.34 cm3/g and 68.93 m2/g, respectively. BET surface area (30.9%) and pore volume (48.2 %) increased for the AAPSA. The significant increase in surface area and pore volume of AAPSA indicates an enhanced number of acid sites and catalytic activity of the acid-modified catalyst towards higher produced biodiesel yield. The optimal conditions for the reaction temperature, reaction time, catalyst loading, and methanol to oil ratio (mtOH/oil) were 55 °C, 142.5 min, 2.5 wt%, and 14.25:1. This resulted in the maximum yield of biodiesel, which was 91.5 %. Moreover, the AAPSA catalyst performed excellently, and the resulting biodiesel fuel's properties are comparable with those of ASTM D6751 and EN 14214 standards. Hence, AAPSA is a potential solid acid bifunctional heterogeneous catalyst to produce biodiesel from BWFO. Therefore, this study's novelty comprises the synthesis of solid acid bifunctional heterogeneous catalyst from giant African land snail shells and the optimization of the process variables involved in the production of biodiesel from BWFO.

Recycled PLA for 3D Printing: A Comparison of Recycled PLA Filaments from Waste of Different Origins after Repeated Cycles of Extrusion.

The objective of this work is to evaluate the reprocessing of PLA 3D printing waste from different origins, into filaments and films, and without the addition of any additive. Two types of waste were considered: a blend of different printing wastes (masks, visors, other components) of personal protective equipment coming from an association of Spanish coronamakers, and PLA waste from a single known commercial source. Both types of materials were subjected to repeated extrusion cycles and processed into films by compression molding. Samples were characterized after each cycle and their mechanical and viscosity properties evaluated. Diffusion-ordered NMR spectroscopy (DOSY) experiments were also carried out to estimate molecular weights. The results show a better performance for the PLA waste from the known origin, capable of withstanding up to three re-extrusion cycles per two for the waste blending, without significant degradation. Additionally, a model to address collection and mechanical recycling cycles under two different scenarios (full traceability and not full traceability) was proposed.

Strength, Stiffness, and Microstructure of Stabilized Marine Clay-Crushed Limestone Waste Blends: Insight on Characterization through Porosity-to-Cement Index.

The porosity-to-cement index (η/Civ) has been extensively applied to study the evolution of different types of soil stabilization. However, this index has still not been used to characterize soils cemented with crushed limestone waste (CLW). In this sense, this paper sought to analyze the applicability of the porosity-to-cement index over the unconfined compressive strength (qu) and initial stiffness at small deformations (Go) of clayey soil improved with CLW and Portland cement. In addition, a microstructural analysis (SEM and EDX tests) was also conducted. CLW addition increased soil strength and stiffness over time. Moreover, qu and Go compacted mixtures containing CLW have established a distinctive correlation. Chemical microanalyses have uncovered a complex interfacial interaction between the soil, cement, and fine CLW particles, leading to a notable reduction in porosity.

An experimental investigation of hydrogen-enriched and nanoparticle blended waste cooking biodiesel on diesel engine

The hazardous effect of the pollution of fossil fuels has brought the necessity of shifting conventional energy sources to renewable and clean ones. In this study, the effect of hydrogen addition and CeO2 nanoparticle addition in waste cooking palm biodiesel on a CRDI engine is evaluated. The dosage of the nanoparticle is fixed at 75 ppm and a hydrogen flow rate of 10 L/min is selected for the engine operations. The crystalline structure of the nanoparticles is determined by XRD analysis. Results showed that on the addition of both H2 and CeO2 in a B20 biodiesel blend (80% diesel and 20% biodiesel) the performance, emission, and combustion parameters of the diesel engine improved compared to neat diesel. The brake thermal efficiency was improved by 3.53% and brake fuel consumption was reduced by 16.12% in comparison to diesel at 90% loading condition. The addition of both nanoparticles and hydrogen in the biodiesel blend lowered the emissions of CO by 30%, and HC and smoke by 50% and 42% respectively. However, NOx increased by 11% as compared to diesel. A 6% higher HRR values and 8% higher in-cylinder pressure were obtained while using hydrogen and CeO2 nanoparticle blended biodiesel. This blend also shows the lowest ignition delay period at full load condition which results in more engine power and efficiency. This experimental study has helped pave the way for the use of hydrogen-enriched and nanoparticle-blended biodiesel in place of fossil fuel for the applications of diesel engines.

Co-Gasification Performance of Low-Quality Lignite with Woody Wastes Using Greenhouse Gas CO2—A TG–MS Study

The carbon dioxide gasification performance of low-quality lignite-agroindustrial/forest waste blends was investigated in terms of reactivity, conversion, cold gas efficiency, product gas composition and heating value. The experiments were conducted in a fixed bed unit and a thermal analysis mass spectrometer system. Raw materials, chars, liquids and gases were quantitatively analyzed and their energy content was determined. Synergetic effects and the role of minerals were examined, the latter through chemical and fusibility analyses of the ashes. Ahlada lignite (AL) was of low quality, with a calorific value of 8.9 MJ/kg. The biomass materials, ginning cotton waste (GCW) and pine needles (PN) had calorific values 16.6 MJ/kg and 20.1 MJ/kg, respectively. The slagging/fouling propensity of AL ash was low, whereas that of biomass wastes was medium to high. Thermal treatment of the samples and their blends prior to gasification produced upgraded fuels. A Boudourd reaction occurred above 750 °C. Gasification reactivity followed the order: GCW &gt; PN &gt; AL. AL/PN mixtures presented additivity effects; however, AL/GCW mixtures presented synergy effects. When the lignite was blended with the biochars studied, its conversion increased from 90% to 94.5% and its cold gas efficiency from 31.8% to 35%. Generated gas attained a heating value of about 12 MJ/m3.

Selective depolymerization of PET to monomers from its waste blends and composites at ambient temperature

Recycling of polyethylene terephthalate (PET), one of the largest varieties of synthetic polymers and the primary textile feedstock, presents a significant challenge when waste PET blends or composites are involved. Despite numerous efforts to address waste PET, it is difficult to achieve energy-efficient and selective depolymerization of PET through physical sorting systems or existing chemical means. Herein, we report a dichloromethane (DCM) and ethanol (EtOH) solvent system to selectively depolymerize PET into monomers while fully recover other mixture components. The complete depolymerization of PET and recovery of more than 99% of terephthalic acid (TPA) monomer can be achieved at room temperature within 30 min. After the reaction, TPA can be separated by simple filtration due to its insolubility in the solution. The filtrate can be reused for the recovery of PET. Molecular dynamics simulation shows that the high activity and selectivity is attributed to activating effect of DCM to PET ester groups, as well as pore-forming effect to promote PET interfacial mass transfer. Environmental energy impact and carbon emissions were evaluated and the results demonstrate the environmental friendliness of this method. This approach enables direct and efficient recycling of PET monomers from waste blends and composites, providing a viable solution to plastic and textile pollution.

Lime-Stabilized Solid-Waste Blends as Alternative Building Blocks in Construction

Abstract Stabilized blocks have been gaining ground in recent times. Stabilized solid waste blocks provide an eco-friendly alternative to conventional fired bricks. The present investigation dealt with the development of lime stabilized blended solid waste blocks comprising fly ash (FA), steel slag (SS) and phosphogypsum (PG). The PG content was limited to 10% and the proportion of FA:SS was varied in the remaining 90% in the ratios of 1:2, 1:1 and 2:1. The blends were stabilized using 2%, 4% and 6% lime. The blends were dry mixed, followed by the addition of a sufficient quantity of water to obtain a uniform wet mix. This mix was then packed into moulds to cast blocks. The blocks were demoulded after 24 hours under wet gunny bags and cured in water for 7 days. Similarly, the blends were also mixed with sand to prepare solid waste mortars blocks and cured for 7 days. At the end of their stipulated curing periods, the stabilized solid waste blocks and mortar blocks were tested for their compressive strength. The results of the investigation revealed that the mix LFSP621 developed the maximum strength of all combinations tested and hence, it can be concluded that the solid waste blend consisting of 60% FA, 30% SS and 10% PG stabilized with a further 6% lime by weight of the solid waste mix was the most optimal mix for developing maximum strength of the solid waste blocks. The mortar blocks, however, met with limited success. Thus, it can be concluded that stabilized solid waste blocks can become an effective alternative building material.