Applied Chemical Engineering

Abstract The global shift toward sustainable manufacturing has intensified interest in eco-friendly materials and optimized processing strategies for additive manufacturing technologies such as Fused Deposition Modeling (FDM). Polylactic acid (PLA)-based green composites have emerged as promising candidates due to their biodegradability, low environmental impact, and compatibility with FDM systems. However, the optimization of FDM process parameters for such composites remains a significant challenge due to the inherent trade-offs between mechanical performance, energy consumption, and material sustainability. This study addresses this gap by employing an integrated multi-criteria decision-making (MCDM) framework—Fuzzy Analytic Hierarchy Process (Fuzzy AHP) combined with Technique for Order Preference by Similarity to Ideal Solution (TOPSIS)—to identify optimal FDM parameter settings for PLA-based green composites. Key process parameters, including layer thickness, print speed, infill density, and nozzle temperature, are evaluated against performance criteria such as tensile strength, surface finish, material utilization, and energy efficiency. Literature reports suggest optimal ranges such as 0.1–0.2 mm for layer thickness, 40–60 mm/s for print speed, and 80–100% for infill density to enhance part strength and minimize waste. The Fuzzy AHP–TOPSIS approach enables robust decision-making under uncertainty, providing a sustainable design methodology aligned with SDGs 4 (Quality Education), 7 (Affordable and Clean Energy), 9 (Industry, Innovation and Infrastructure), and 12 (Responsible Consumption and Production). This study establishes a foundational framework for future experimental validation and promotes informed parameter selection for sustainable, high-performance FDM manufacturing of PLA-based green composites.

Abstract The rising demand for environmentally responsible manufacturing has intensified interest in biodegradable polymers for additive manufacturing (AM). Polylactic Acid (PLA), a bio-based thermoplastic, is widely utilized due to its renewability and ease of processing. However, its inherent brittleness, low thermal resistance, and limited mechanical strength restrict its suitability for structural or load-bearing applications. This study addresses these limitations by developing and characterizing wood fiber (WF)-reinforced PLA composites aimed at improving mechanical performance and sustainability in AM, particularly Fused Deposition Modeling (FDM). Although natural fiber-reinforced biopolymers have shown promise, prior research often neglects eco-friendly processing, cost-effective preparation, and systematic optimization of fiber content and printing conditions. To overcome these gaps, sustainable composite filaments were produced using solvent-free melt compounding and extrusion techniques. Standardized specimens were fabricated via FDM and subjected to tensile, flexural, and compressive testing to assess mechanical properties. A multi-criteria decision-making (MCDM) approach was further employed to optimize printing parameters, balancing strength, energy efficiency, and material utilization. Results demonstrate that PLA-WF composites exhibit significant property enhancements, with tensile and flexural strengths improving by ~18% and ~22%, respectively, compared to neat PLA. The addition of WF not only strengthens structural performance but also lowers cost and reduces environmental impact, while maintaining good printability and dimensional stability. These findings highlight the potential of PLA-WF composites as sustainable alternatives for functional AM components and align with multiple United Nations Sustainable Development Goals (SDGs), including SDG 9, SDG 12, SDG 13, and SDG 15.

Abstract The use of hydrogen as an energy carrier has gained significant attention due to its environmentally friendly characteristics. Among various production methods, steam reforming of natural gas (CH₄) remains the most cost-effective and widely adopted technique. To enhance the efficiency and carbon utilization of this process, a novel hybrid steam and dry reforming reactor has been proposed, which utilizes the CO₂ produced from steam reforming within a dry reforming zone. In this study, a two-dimensional axisymmetric hybrid catalytic membrane reactor (CMR) model was developed for the production of pure hydrogen from natural gas, employing a Pd–Ru metallic membrane and a carbonate dual-phase membrane, integrated with Ni/Al₂O₃ and Rh/Al₂O₃ catalysts. A computational fluid dynamics (CFD) approach was employed to investigate the reactor’s performance in terms of methane conversion and hydrogen production under various operating conditions. These include reaction temperatures of 700, 800, 900, and 1000 K, a gas hourly space velocity (GHSV) of 1000 h⁻¹, and a sweep gas Reynolds number (Re) of 100. Simulation results revealed that the CMR achieved a high hydrogen permeation rate on the permeate (tube) side, along with a maximum CH₄ conversion of approximately 99.9% at 1000 K on the retentate side within the steam reforming zone. Furthermore, the reactor demonstrated effective syngas production with near-complete CO₂ reduction on the dry reforming side, where CO₂ concentrations at the reactor outlet approached zero at 1000 K. These findings highlight the promising potential of the hybrid combined membrane reactor (CMR) system for efficient hydrogen production and near-complete carbon utilization.

Abstract The integration of bio-based materials in additive manufacturing is a key strategy in aligning with the Sustainable Development Goals (SDGs 9, 11, 12, and 13), particularly for fostering sustainable urban infrastructure and reducing environmental impact. This study investigates the surface metamorphosis of fused deposition modeling (FDM)-printed polylactic acid (PLA) and PLA reinforced with wood fibers (PLA+WF), using a combined microstructural and analytical chemistry approach to enhance surface functionality. Employing scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and surface profilometry, we characterized the morphological and chemical transformations induced by post-processing treatments such as controlled thermal annealing and solvent vapor exposure. The PLA+WF composites exhibited a 38% reduction in surface roughness (Ra) and a 22% increase in hydrophilicity compared to untreated PLA, facilitating better coating adhesion and reduced microbial accumulation. FTIR analysis confirmed the retention of key ester and cellulose functional groups post-treatment, ensuring material integrity. Moreover, thermal post-treatment improved the crystallinity index by 18% in PLA and 27% in PLA+WF, suggesting enhanced mechanical stability. These findings present a viable pathway for producing high-performance, bio-based components with improved surface characteristics, directly contributing to the development of sustainable, low-impact technologies in urban applications.

Abstract The study aimed to evaluate the impact of organic, mineral, and nano-enabled fertilizers on soil sustainability and the growth and yield of cabbage (Brassica oleracea). A field experiment was conducted during the autumn season of 2024 in District 41, Babil Governorate, Iraq, using 16 treatments arranged in a randomized complete block design (RCBD). Treatments included EM Bokashi bio-organic fertilizer, balanced NPK mineral fertilizer, and foliar sprays of silicon and selenium nanoparticles, applied individually or in combinations. The integrated treatment of EM Bokashi + NPK + SiNPs + SeNPs significantly improved soil fertility indicators (N, P, K, organic matter, and cation exchange capacity), enhanced microbial populations, and produced the highest plant growth and yield attributes, including a marketable yield of 100.42 Mg ha⁻¹. These findings highlight the potential of combining organic, mineral, and nano-fertilizers as a sustainable strategy to improve soil health, crop productivity, and future agricultural profitability.

Abstract Stereolithography (SLA) has emerged as a superior additive manufacturing technique compared to Fused Deposition Modeling (FDM), offering smoother surface finishes and higher dimensional accuracy. However, conventional SLA resins remain limited by brittleness, poor thermal stability, and weak coating adhesion. In this study, a hybrid photopolymer resin incorporating nano-silica fillers (0.5–2.0 wt%) and functional oligomers was formulated, alongside plasma–silanization surface treatments, to enhance coating performance of SLA-printed parts. Mechanical testing showed a peak improvement at 1.0 wt% nano-silica, where tensile strength increased by 35.9% (from 32.5 MPa to 44.2 MPa), Young’s modulus by 36.2% (870 MPa to 1185 MPa), and flexural strength by 29.9% (58.9 MPa to 76.5 MPa). Shore D hardness rose from 78 to 84, while thermal analysis revealed an upward shift in glass transition temperature from 64.2 °C to 70.5 °C and degradation onset temperature from 281 °C to 301 °C. Surface wettability improved significantly, with water contact angle reduced from 89.3° to 54.7°, raising surface energy from 32.4 to 51.1 mN/m. Coating adhesion (ASTM D3359) improved from grade 3B to 5B, and wear resistance increased by 40% (wear index reduced from 0.125 to 0.075 mg/cycle). These results validate the dual-pathway approach of resin reinforcement and post-print surface modification, enabling SLA-printed parts to overcome typical FDM limitations of poor surface fidelity and weak interfacial bonding. The developed system demonstrates strong potential for high-performance coatings in biomedical, optical, and microfluidic device applications.

Abstract Inappropriate use of plants represents a significant public health risk that is often underestimated. This study aims to determine the profile and consequences of intentional plant intoxication in Morocco over a 13-year period. This study was based on a retrospective analysis of cases of intentional plant intoxication reported to the Moroccan Poison Control and Pharmacovigilance Centre (MPCPC) between 1 January 2010 and 31 December 2022. The significance level was set at 5%. During the study period, the MPCPC recorded 189 cases of intentional herbal intoxication, representing 9.37% of all herbal intoxications occurring during this period (2016 cases). The average age of the patients was 29.77 years, with the majority being young adults (68.25%), adolescents (14.28%) and children under 15 (7.93%). The sex ratio (M/F) was 0.41 (71.04% female). Suicide attempts were the main cause of poisoning (87 cases), with Atractylis gummifera being the most commonly implicated plant (17 cases). Twenty-two cases were related to abortions, mainly caused by Peganum harmala (45.45%), drug addiction (16 cases), of which Datura stramonium was the most incriminated plant (5 cases), and plant mixtures (63.63%) were the most commonly used in criminal activities (11 cases). The route of administration was mainly oral (162 cases). Digestive, neurological and cardiac disorders, renal failure, rhabdomyolysis and liver damage were reported. The outcome was favourable in 103 cases, fatal in 4, including a 9-year-old girl who ingested Rumex divers, with sequelae in 2 cases and unknown in 80 cases. Calculation of the p-value revealed that several variables were highly significant. Inappropriate use of plants poses a significant risk to public health. It is essential to raise awareness of the dangers associated with these plants and to emphasise the importance of appropriate psychiatric support in cases of intentional intoxication.

Abstract Balanced carbon–sulfur (C-S) dynamics are crucial for maintaining soil fertility and sustaining crop productivity. This study examined how mineral and biofertilizers affect total sulfur (S), organic carbon (OC), and the C/S ratio in maize rhizosphere and bulk soils. A field experiment was established with six treatments: an unfertilized control, urea (250 kg N ha⁻¹), ammonium sulfate (200 kg N ha⁻¹), BioHealth biofertilizer (4–5 kg N ha⁻¹), liquid effective microorganisms (EM, 400 L ha⁻¹), and a combined fertilizer containing one-quarter of each recommended dose. Total S, OC, and C/S ratios were measured after 70 and 100 days of maize growth. Ammonium sulfate consistently produced the highest sulfur concentrations in both rhizosphere and bulk soils, with increases of more than 40% over the control at both sampling times. The combined fertilizer treatment significantly enhanced OC content in both soil compartments, with up to a 25 % increase compared with the control. Urea yielded the greatest C/S ratio (approximately 15 % higher than the control), while all treatments showed a progressive decline in C/S as sulfur availability increased, confirming an inverse S-C/S relationship. These results demonstrate that integrating bio- and mineral fertilizers improves soil C–S balance and nutrient availability, offering a practical strategy to enhance soil fertility and support sustainable maize production.

Abstract This study investigates the valorization of polyethylene household waste through chemical modification to develop environmentally sustainable composite materials. Secondary polyethylene (PE) was treated with elemental sulfur and melamine as chemical modifiers to enhance its properties. The modified PE was characterized using advanced spectroscopic techniques, including Fourier-transform infrared spectroscopy (FTIR) and other analytical methods, in accordance with ISO standards. Physical and mechanical properties, such as tensile strength, elongation at break, and hardness, were systematically evaluated to assess the performance of the resulting composites. The integration of melamine and chemically modified sulfur into secondary PE yielded materials with improved mechanical robustness and functional characteristics suitable for various industrial and consumer applications. This approach demonstrates an effective strategy for reducing polyethylene waste by converting it into value-added, functional composites, thereby promoting ecological sustainability and waste minimization. The findings underscore the potential of chemically modified secondary polyethylene as a viable resource for sustainable material development, contributing to environmental conservation and waste management efforts. Overall, this methodology offers a promising route for the reutilization of polyethylene household waste, aligning with principles of circular economy and ecological responsibility.

Abstract Additive manufacturing (AM) is transitioning from rapid prototyping toward sustainable, production-level technologies, making energy efficiency a critical performance metric alongside part quality. Among AM methods, Stereolithography (SLA) and Fused Deposition Modeling (FDM) dominate consumer and industrial adoption, yet their comparative energy footprints remain insufficiently quantified. Existing literature reports FDM printers typically draw 100–250 W due to heated beds and extrusion systems, whereas SLA systems generally consume 50–100 W, but most studies rely on manufacturer specifications rather than empirical data. To address this gap, this work conducts a state-of-the-art comparative energy analysis of SLA and FDM printing using real-time wattmeter monitoring under standardized benchmark conditions. Using a Bambu Lab A1 (FDM) and an ELEGOO Saturn 4 Ultra (SLA), identical parts (~20 cm³) were printed, and consumption normalized by part mass and volume. Results revealed that FDM consumed 81.3 Wh/part (0.89 Wh/g, 0.98 Wh/cm³) with peak loads of 265 W, while SLA required only 48.2 Wh/part (0.51 Wh/g, 0.57 Wh/cm³) with a maximum of 112 W. SLA also exhibited lower standby power (2.8 Wh/h vs. 6.1 Wh/h for FDM) and reduced variability (±3.2% vs. ±7.4%), highlighting its stability and efficiency. These findings extend prior state-of-the-art studies by providing empirical, high-resolution energy profiles across full print cycles and normalized metrics, enabling fair comparison. By positioning SLA as more energy-efficient for high-resolution parts and FDM as more favorable for mechanically demanding applications, this study contributes to sustainable AM practice and supports decision-making aligned with SDGs 7, 9, 12, and 13.