Mantana Opaprakasit

Metal-organic framework (MOF) based on iron (III) and terephthalate (TPA) linker is attractive for CO2 capture due to its Lewis-acidic open metal sites. However, precise control of pore surface chemistry remains challenging. Herein, we present a sustainable strategy that upcycles polystyrene (PS) waste into functional crystal growth modulators for tuning Fe-based MOF via microwave-assisted synthesis. Oxidatively degraded polystyrene (OPS) products, generated through nitric acid oxidative degradation, were introduced at molar ratios of 0.04 – 0.40 relative to TPA linkers. At low OPS loading, the MOF-235 structure is retained, with a slight increase in crystallite size (96.2 vs. 88.2 nm), suggesting a modulation effect on crystal growth. An optimized sample (OPS004@MOF) achieved a CO₂ uptake of 0.977 mmol g-1 (13% higher than pristine MOF-235) and an enhanced CO2/N2 selectivity of 2.71 (+62%). Thermogravimetric and spectroscopic analyses suggest interactions between OPS-derived species and the Fe-TPA framework, leading to modification of the local pore environment and enhanced CO2 adsorption behavior. In contrast, higher OPS loadings induce reduced crystallite size and partial phase transformation toward MIL-88B, leading to diminished adsorption performance. This work demonstrates a circular approach that converts plastic waste into functional modulators, enabling controlled structure tuning and enhanced CO2 capture performance in Fe-based MOFs.

An environmentally friendly magnetic metal–organic framework (MMOF) based on MIL-53(Al) was synthesized using terephthalic acid (TPA) recovered from polyethylene terephthalate (PET) waste as the organic linker. The Fe2O3@MIL-53(Al) adsorbent was fabricated through a layer-by-layer assembly, with polyethylenimine (PEI) bridging the Fe2O3 core (∼200 nm) and MIL-53(Al) shell (∼25 nm). A uniform MOF layer was achieved in a single cycle under green synthesis conditions with PEI concentrations ≥ 10 g/L. The MMOF efficiently removed organophosphate pollutants, particularly 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), a common scale and corrosion inhibitor. Adsorption kinetics across a pH range of 3–10.5 closely match the pseudo-second-order kinetic model, indicating chemisorption. The adsorption capacity ranged from 250 to 460 mg/g, with a maximum surface-normalized capacity of 0.44 mg/m2 at pH 5.5, attributed to favorable electrostatic interactions. Adsorption performance was strongly influenced by both the MMOF zeta potential and the ionization state of PBTC. The well-fitted adsorption isotherms (R2 > 0.9) to the Freundlich, Temkin, and Henry models indicate heterogeneous surface adsorption mechanisms. Electrostatic attraction, hydrogen bonding, and surface complexation are proposed as the dominant mechanisms. Overall, the Fe2O3/PEI/MIL-53(Al) composite exhibits high adsorption capacity, broad pH stability, and low toxicity, highlighting its promise for efficient PBTC antiscalant removal applications.

Alcoholysis is a promising approach for upcycling postconsumer polylactide (PLA) products into valuable constituents. In addition, an alcohol-acidolysis of PLA by multifunctional 2,2-bis(hydroxymethyl)propionic acid (DMPA) produces lactate oligomers with hydroxyl and carboxylic acid terminals. In this work, a process for sizing down commercial PLA resin to optimum medium-sized lactate oligomers is developed at a lower cost than a bottom-up synthesis from its monomer. The microwave-assisted reaction is conveniently conducted at 220–240 °C and pressure lower than 100 psi. The PLA resin was completely converted via alcohol-acidolysis reaction, with a product purification yield as high as 93%. The resulting products are characterized by FTIR, 2D-NMR, ¹H-NMR, GPC, DSC, and XRD spectroscopy. The effects of PLA: DMPA feed ratios and the incorporation of 1,4-butanediol (BDO) on the structures, properties, and particle formability of the alcohol-acidolyzed products are examined. The products from a ratio of 12:1, which possessed optimum size and structures, are used to synthesize PLA-based polyurethane (PUD) by reacting with 1,6-diisocyanatohexane (HDI). The resulting PUD is employed in encapsulating lavender essential oil (LO). Without using any surfactant, stable LO-loaded nanoparticles are prepared due to the copolymer’s self-stabilizability from its carboxylate groups. The effect of the polymer: LO feed ratio (1.25–3.75: 1) on the physicochemical properties of the resulting nanoparticles, e.g., colloidal stability (zeta potential > -60 mV), hydrodynamic size (300–500 nm), encapsulation efficiency (80–88%), and in vitro release, are investigated. The LO-loaded nanoparticles show non-toxicity to fibroblast cells, with an IC₅₀ value higher than 2000 µg/mL. The products from this process have high potential as drug encapsulation templates in biomedical applications.

A process for surface modification of LDPE films has been developed by employing chitosan (CS), alkyl ketene dimer (AKD), and glutaraldehyde (GA). Surface roughness and polar reactive groups were generated on the film surfaces by etching with chromic acid at 30 min. The polar groups interact/react with CS/AKD/GA, forming a highly stable coating layer. At optimum conditions (24 µm coating thickness), the film’s antibacterial properties (99.9% inhibition) and hydrophobicity are drastically enhanced. The film’s mechanical and optical properties and crystalline characteristics remain unchanged. The facile process has a high potential for fabricating functional films in food packaging and greenhouse applications.