Carolina Iacovone

Effective arsenic remediation requires maximizing the loading and accessibility of active iron phases, a persistent challenge that has limited the development of practical superadsorbents. Here, a seed‐assisted anisotropic growth strategy is applied to electrospun poly(vinyl alcohol)/pectin nanofibers by sequentially introducing Fe ²⁺ and Fe ³⁺ ions. This dual‐ion approach generates ∼2‐nm iron seeds that direct the growth of rice‐grain‐like iron oxyhydroxide nanostructures (29 ± 6 nm × 110 ± 20 nm; aspect ratio ∼4), achieving loadings and surface accessibility unattainable with conventional single‐doping. The resulting morphology exhibits a high iron content (1.72% at, a 12‐fold increase over single‐ion doping [0.04%–0.14%]), yielding a superadsorbent that reduces As(V) from 1 mg L ⁻¹ at pH 6 to below the WHO guideline (10 µg L ⁻¹ , ∼99% removal) using only 1 g L ⁻¹ dose. High removal efficiency is retained at neutral and basic pH (∼30 µg L ⁻¹ ), substantially outperforming single‐doped materials ([245 ± 15] µg L ⁻¹ , ∼75% removal). Structural analysis (FE‐SEM, EDS, SAXS, WAXS) elucidates the seed‐mediated growth mechanism, whereas kinetic and isotherm studies indicate chemisorption and accelerated cooperative binding. The material is reusable over several cycles, and remains effective in the presence of competing ions, establishing seed‐mediated growth as a powerful route to high‐performance nanostructured superadsorbents.

Metal-organic frameworks (MOFs) offer high porosity for water remediation but face challenges in handling as powders. We address these limitations by physically immobilizing Fe–BTC MOF within calcium-crosslinked low-methoxyl pectin matrices (PE–Ca–MOF). Solvent-cast films and freeze-dried foams were fabricated using water-based and polyvinylpyrrolidone (PVP)-assisted Fe–BTC dispersions, preserving MOF and pectin structures confirmed by FT–IR. PVP improved Fe–BTC dispersion and reduced particle size, enhancing distribution and plasticizing the matrix proved by DSC. Incorporation of water-dispersed Fe–BTC increased the equilibrium adsorption capacity but reduced the initial adsorption rate, while the PVP-assisted foam further enhanced uptake in comparative batch tests through its more open porous structure. At pH 7, PE–Ca–5%MOF films showed high adsorption capacities and removal efficiencies for paraquat (35.5 mg/g, 70.6%) and tetracycline (14.5 mg/g, 46.8%), while maintaining Zn²⁺ uptake compared to calcium-pectin films without MOF. Adsorption followed pseudo-first-order kinetics and Langmuir isotherms. Green regeneration with acetic acid enabled >80% capacity retention over five adsorption–desorption cycles. Foam architectures increased porosity and active-site accessibility (SEM), improving performance even at lower MOF loadings. Overall, controlling MOF dispersion and composite morphology enables efficient, reusable, and environmentally friendly bio-based adsorbents for water purification.

Biodegradable polymers have been strongly recognized as an alternative to replace traditional petrochemical plastics, which have become a global problem due to their long persistence in the environment. In this work, the effect of the addition of titanium dioxide nanoparticles (TiO₂NP) on the morphology, physicochemical properties and biodegradation under industrial composting conditions of cassava starch-based nanocomposites obtained by extrusion at different screw speeds (80 and 120 rpm) were investigated. Films performed at 120 rpm (S₁₂₀ and S₁₂₀-TiO₂NP) showed completely processed starch and homogeneously distributed nanoparticles, leading to much more flexible nanocomposites than those obtained at 80 rpm. The incorporation of TiO₂NP led to an increase in storage modulus of all films and, in the case of S₁₂₀-TiO₂NP, to higher strain at break values. From the Kohlrausch–Williams–Watts theoretical model (KWW), an increase in the relaxation time of the nanocomposites was observed due to a decrease in the number of polymer chains involved in the relaxation process. Additionally, S₁₂₀-TiO₂NP showed effective protection against UV light, greater hydrophobicity and faster biodegradation in compost, resulting in a promising material for food packaging applications.