A novel porous lignocellulosic standing hierarchical hydroxyapatite for enhanced aqueous copper(II) removal

Facile fabrication of electrospun hybrid nanofibers integrated cellulose, chitosan with ZIF-8 for efficient remediation of copper ions

To removal copper ions (Cu2+) from wastewater, structurally stable microcrystalline cellulose (MCC)/chitosan (CS)/zeolitic imidazole framework-8 (ZIF-8) hybrid nanofibers were fabricated by mixing electrospinning (MCC/CS/ZIF-8) and in-situ grown of ZIF-8 on electrospun nanofibers (I-MCC/CS/ZIF-8). The microstructure, porosity, thermal stability, crystal structure, surface wettability, chemical groups of hybrid nanofibers as well as their adsorption performance, isotherms, and kinetics were characterized and analyzed. The rhombohedral ZIF-8 at the optimum synthesis ratio was evenly bounded to nanofibers, corresponding to an average diameter of 775.81 nm. The introduction of ZIF-8 effectively improved the thermal stability of biomass polysaccharide nanofibers, maintained beneficial hydrophilicity (25.08°), increased their specific surface area by 16.51 times, and provided abundant potential active sites for Cu2+ adsorption. The adsorption performance of I-MCC/CS/ZIF-8 was superior to that of MCC/CS/ZIF-8, achieving the maximum Cu2+ adsorption capacity of 204.08 mg g-1 at pH = 5, which conformed to both the Langmuir model and the pseudo-second-order kinetic model. The enhanced mechanism for Cu2+ adsorption can be attributed to the sufficient channels of porous network and the strong hydrogen bonding facilitating physical adsorption, as well as the effective chemical adsorption resulting from the rapid growth of ultrathin lamellar copper oxide‑zinc oxide heterojunctions with nanoflower-like shapes.

Scalable fabrication of freely shapable 3D hierarchical Cu-doped hydroxyapatite scaffolds via rapid gelation for enhanced bone repair

Critical-sized bone defects present a formidable challenge in tissue engineering, necessitating innovative approaches that integrate osteogenesis and angiogenesis for effective repair. Inspired by the hierarchical porous structure of natural bone, this study introduces a novel method for the scalable production of ultra-long, copper-doped hydroxyapatite (Cu-HAp) fibers, utilizing the rapid gelation properties of guar gum (GG) under controlled conditions. These fibers serve as foundational units to fabricate three-dimensional porous scaffolds with a biomimetic hierarchical architecture. The scaffolds exhibit a broad pore size distribution (1-500 μm) and abundant nanoporous features, mimicking the native bone extracellular matrix. Physicochemical characterization and in vitro assays demonstrated that the copper doping significantly enhanced osteogenic and angiogenic activities, with optimized concentrations (0.8 % and 1.2 % Cu) facilitating the upregulation of osteogenesis-related genes and proteins, as well as promoting endothelial cell proliferation. In vivo studies further confirmed the scaffolds' efficacy, with the 1.2Cu-HAp group showing a remarkable increase in bone regeneration (bone volume/total volume ratio: 35.7 ± 1.87 %) within the defect site. This research offers a promising strategy for the rapid fabrication of multifunctional scaffolds that not only support bone tissue repair but also actively accelerate the healing process through enhanced vascularization.

Exploring feasibility of citric acid infused lignocellulosic waste derived from chestnut and water melon peels for phytofiltration of Eosin yellow dye from water

The adsorption efficiency of cheap, ecofriendly, and easily available agro-waste, Trapa natans (Chestnut) and Citrullus lanatus (Watermelon) peels, has been investigated in their native forms (TNAT and CLAN) as well as citric acid impregnated forms (C-TNAT and C-CLAN), respectively, for the detoxification of toxic, deleterious, and carcinogenic Eosin yellow dye (EYD) from wastewater streams. Different operational parameters were optimized for the investigation of isothermal, kinetic and the thermodynamic models. R2 for sportive decontamination of Eosin by citric acid treated adsorbents were close to one, supporting the applicability of Langmuir, Temkin, and pseudo-second-order in this investigation. Maximum sorption capabilities were 222 and 667 mg/g for chemically treated bio-waste C-TNAT and C-CLAN, respectively, reflecting their efficient and promising performance, while Gibbs free energy revealed exothermic and spontaneous adsorption behavior. The kinetic statics for qe (cal) are quite close to qe (exp), indicating the viability and fitness of pseudo-second-order mechanisms. The present study suggests that both citric acid fabricated bio-waste C-TNAT and C-CLAN can be substantially employed to decontaminate persistent organic pollutants, like: Eosin yellow dye from wastewater using green approach to resolve socio-economic problems of developing countries.

Self-assembly of metal-polyphenolic network on biomass for enhanced organic contaminant capturing from water with a high cost-to-benefit ratio

Nanomaterials present a vast potential as functional materials in environmental engineering. However, there are challenges with nanocomplex for recyclability, reliable/stable, and scale-up industrial integration. Here, a versatile, low-cost, stable and recycled easily metal-polyphenolic-based material carried by wood powder (bioCar-MPNs) adsorption platform was nano-engineered by a simple, fast self-assembly strategy, in which wood powder is an excellent substrate serving as a scaffold and stabilizer to prevent the nanocomplex from aggregating and is easier to recycle. Life cycle analysis highlights a green preparation process and environmental sustainability for bioCar-MPNs. The metal-polyphenolic nanocomplex coated on the wood surface in bioCar-MPNs presents a remarkable surface adsorption property (1829.4 mg/g) at a low cost (2.4 US dollars per 1000 g bioCar-MPNs) for organic dye. Quartz crystal microbalance analysis (QCM) demonstrates an existing strong affinity between polyphenols and organic dyes. Furthermore, Independent Gradient Model (IGM) and Hirshfeld surface analysis reveal the presence of the electrostatic interactions, π-π interactions, and hydrogen bonding. Meanwhile, adsorption efficiency of bioCar-MPNs maintains over 95% in the presence of co-existing ions (Na+, 0.5 M). Importantly, the reasonable utilization of biomass for water treatment can contribute to achieving the high-value and resource utilization of biomass materials.