Global Impact Journal: Sustainable Chemistry & Innovation

Selective Biosorption of Hg(II), Cd(II), and Pd(II) on Functionalized Chitosan (–SH/–COO−): A DFT Study with ESP/MEP and NCI/RGD Analyses

Joaquín Hernández-Fernández — 2026-08-17

In this work, density functional theory (DFT) was used to comparatively investigate the thermodynamic and electronic factors governing the association of Cd(II), Hg(II), and Pd(II) with native chitosan (CTS) and functionalized derivatives (CTS–COOH, CTS–COO−, CTS–NH3⁺, and CTS–SH). Representative acid–base states were considered to approximate changes in site availability, and a uniform explicit microhydration scheme was adopted to enable controlled relative comparisons across metals and materials. Within this framework, the calculated free energies suggest metal-dependent affinity regimes: the carboxylic microenvironment favors Cd(II), the thiolated microenvironment provides the most favorable association for Hg(II), and native CTS affords the strongest calculated stabilization for Pd(II). Geometry optimizations show that most complexes retain the first hydration sphere of the metal, indicating that stabilization is dominated by outer-sphere association rather than by systematic first-sphere ligand substitution. ESP/MEP maps reveal that the heterogeneity and directionality of the electrostatic landscape govern selectivity. In contrast, NCI analysis supports a cooperative contribution of weak interactions and second-sphere organization. These results provide a comparative electronic framework to guide future experimental validation of selective metal capture by functionalized chitosan materials.

Adsorption Performance for Ruthenium with Dendrimer-Grafted Chitosan from Acidic Solution

Baomei Fu — 2026-08-31

Ruthenium possesses outstanding properties and is widely utilized in many fields. However, its natural scarcity makes the recovery of ruthenium from waste liquids particularly important. A dendrimer-grafted chitosan adsorbent is synthesized through Michael addition and amidation reactions on chitosan, which is then used to adsorb Ru(III) from aqueous solutions. Compared with unmodified chitosan, this adsorbent has abundant binding sites and can rapidly and efficiently adsorb Ru(III) through electrostatic attraction and complexation. Characterization techniques, including FT-IR, XPS, and SEM, confirmed successful modification. Adsorption experiments show that this adsorbent exhibits an adsorption efficiency of up to 97.79% for Ru(III) and saturated adsorption capacity of 162 mg/g. The results of competitive adsorption experiments demonstrate that the adsorbent has good selectivity for Ru(III), retaining 71.22% of adsorption efficiency after five cycles. This work offers a new possibility for the environmentally friendly and efficient recovery of Ru(III) from wastewater.

Cleaner Chemistry for Clean Energy: PFAS-Free Materials in PEM Electrochemical Technologies

Erasmo Salvatore Napolitano — 2026-08-31

Per- and polyfluoroalkyl substances (PFAS) have found wide application in proton exchange membrane fuel cells (PEMFCs) and water electrolysers (PEMELs), thanks to their exceptional chemical and thermal stability. However, their environmental persistence and growing regulatory pressure—particularly from the European Union—have made the transition to PFAS-free components a priority. This work reviews current advancements in alternative materials that can guarantee the same performance or maybe improve it. Although several non-fluorinated materials have demonstrated initial performance close to PFAS-based benchmarks, significant challenges remain. These include limited long-term stability, difficulties for new materials to fit into existing stack architectures, and the lack of standardized testing protocols. Nevertheless, recent efforts have successfully demonstrated a PFAS-free PEM electrolyser stack at TRL 4, validating the technical feasibility of full PFAS substitution. Achieving commercial readiness will require parallel progress in materials development and industrial scalability. This review highlights the possibility that hydrogen technologies, such as fuel cells and electrolysers, which are called upon to support the energy transition towards a more sustainable future, are themselves truly environmentally friendly, thus making their use as green as possible.

Water-Based Pretreatment Combined with Severity-Optimized Organosolv Enables Near-Complete Enzymatic Hydrolysis of Wheat Straw at Reduced Energy Demand

Tianyi Guo — 2026-05-16

Wheat straw is an abundant agricultural residue with high potential for carbohydrate-based bioconversion, yet its efficient utilization is limited by lignocellulosic recalcitrance. This study systematically investigated Organosolv extraction of wheat straw (Triticum aestivum) with the goal of achieving near-complete enzymatic hydrolysis at minimized process severity and energy demand. Process severity was evaluated using the P-Factor concept. In preliminary screening, acid catalysts and liquor ratios were assessed. Strong acids clearly outperformed weak acids: at comparable severity, 5% (w/w, DM) H₂SO₄ or p-toluenesulfonic acid (PTSA) yielded glucose yields of 83 ± 2.4% and 81 ± 6.2%, respectively, whereas weak acids (phosphoric, lactic, acetic) and a catalyst-free control resulted in only approximately 20–41% glucose yield. Liquor ratio strongly affected extraction performance; a ratio of 1:19 provided the highest glucose yield (85 ± 1.4%) and robust mixing compared to 1:12–1:15 (67–68%). Two novel pretreatment strategies applied prior to Organosolv extraction, namely Hot-Water Pretreatment (HWP) and Water Pretreatment (WP), significantly increased hydrolysability compared to untreated straw (58 ± 3%), reaching 79 ± 2% for HWP and 86 ± 5% for WP. DoE-based experiments (135–170 ^◦C; P-Factor 3.0–4.0) showed that increasing temperature from 135 to 150 ^◦C markedly improved hydrolysability (e.g., WP: 74 ± 3% to 96 ± 3%), while further increasing to 170 ^◦C provided no additional benefit. Response-surface modeling predicted a maximum hydrolysability of approximately 88% for HWP but complete hydrolysis for WP within 152–170 ^◦C, indicating a broad operational window. Overall, combining simple Water-based Pretreatment with severity-optimized Organosolv extraction enables energy-efficient, near-complete hydrolysis at lower operating temperatures, reducing both energy demand and pressure requirements, and thereby offering advantages in process cost and scalability.

Valorization of Thermoplastic Polyurethane and Styrofoam Waste for Development of Improved Sustainable Blend Membranes

Tutik Sriani — 2026-08-31

This study aimed to improve the mechanical integrity of Styrofoam membranes fabricated from post-consumer food packaging. To this end, 3D-printing byproduct—thermoplastic polyurethane (TPU) waste—was blended with polyimide (PI) in the membrane dope solution. The synthesized flat-sheet upcycled membranes were evaluated via scanning electron microscopy (SEM), water contact angle (WCA), and tensile testing, while separation efficiency was determined through bovine serum albumin (BSA) rejection and permeation trials. Findings indicate that incorporating TPU into the Styrofoam/PI matrix increased tensile strength by 50%, BSA rejection by 12.4%, and permeation by 33%. Compared with pristine Styrofoam membranes, tensile strength and BSA rejection improved by 240% and 46%, respectively. Although the blend membranes exhibited a reduction in water flux (from 214 to 162.5 LMH/bar) due to pore contraction, they maintained high rejection rates (~86%) for large macromolecules like PVP (1300 kDa). Furthermore, while all membranes remained hydrophilic, hydrophobicity scaled with TPU concentration.