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This work aimed to synthesize the aluminium oxide nanoparticles using Ixoro coccinea leaf extract. Furthermore, the synthesized Ixoro coccinea aluminium oxide nanoparticles (I–Al2O3-NPs) and nanocomposites (I–Al2O3-NC), including them as the fillers in a chitosan matrix were characterized, and I–Al2O3-NC was applied to remove the toxic metals (TMs) including Cd, Ni, and Pb from water. Optimization of different batch experimental adsorption parameters (pH, concentration of TMs, dose of I–Al2O3-NC, temperature, and time of contact) was done to check the feasibility of I–Al2O3-NC for maximum removal of TMs from water. The extreme adsorption capacities using nanocomposites for Cd, Ni, and Pb were 66.0, 60.0, and 66.4 mg g−1, respectively. The I–Al2O3-NC followed the Freundlich isotherm model for removing Cd and Ni while showing the monolayer surface coverage for the removal of Pb. For this process, the best-fitted kinetic model was the pseudo-second-order equation. The enthalpy, entropy, and free energy of metal ion adsorption, among other parameters of thermodynamics, were estimated. The process was found to be exothermic, advantageous, and spontaneous. Kinetic studies show that intra-particle diffusion is essential for eliminating TMs. In addition, I–Al2O3-NC was applied for the adsorption of TMs from surface water and determined to be effective in removing these contaminants up to an acceptable drinking water standard. Regeneration of adsorbent suggested that green synthesized I–Al2O3-NC may be an active tool for removing Cd, Ni, and Pb ions from contaminated water. © 2023 Elsevier Ltd and Techna Group S.r.l.

The current study aimed to synthesize and characterize the Duranta erecta leaves extract-based iron oxide nanoparticles (D-Fe3O4-NPs) and chitosan biopolymer-based nanocomposites (D-Fe3O4-NC). The synthesized D-Fe3O4-NC was applied for the adsorptive removal of cadmium (Cd), chromium (Cr), and lead (Pb) from water. The nanostructure, porous, rough, crystalline structure, and different functional groups of chitosan and D-Fe3O4-NPs in D-Fe3O4-NC showed that the D-Fe3O4-NC is feasible for suitable adsorbents for quantitative removal of Cd, Cr, and Pb. Based on the batch experiments, the influences of pH, adsorption time, contents of Cd, Cr, and Pb in solution, and temperature were successfully optimized. The adsorption capacities of D-Fe3O4-NC for Cd, Cr, and Pb were observed at 74.4, 76.0, and 75.2 mg g−1, respectively. The adsorption isotherms fitted the Freundlich Model equation well, and the adsorption kinetics followed pseudo-second-order kinetics for the adsorption of these toxic metals. D-Fe3O4-NC showed an excellent recyclable efficiency up to multiple analyses (n = 20). The D-Fe3O4-NC was an excellent adsorbent for removing toxic metals from municipal and hand pump water samples (% removal >93%). Therefore, the proposed D-Fe3O4-NC is the most efficient and selective adsorbent for removing Cd, Cr, and Pb from drinking water up to recommended permissible limit. © 2023 Elsevier B.V.

© 2016 Elsevier Ltd. All rights reserved.Poly(3hydroxybutyrate-co-4hydroxybutyrate) (P(3HB-co-4HB)) is a polyhydroxyalkanoate (PHA), which is known for its properties and performance leading to a wide range of applications. Compared to more conventional PHAs such as P(3HB) or P(3HB-4HV), P(3HB-co-4HB) is known for its mechanical properties. P(3HB-co-4HB) has the potential to replace some fossil-based thermoplastics in certain fields. However, it is thermally sensitive like most PHAs and this puts limitations on its potential as an important biobased and biodegradable polymer. The present work is based on the study of multiphase systems of P(3HB-co-4HB) elaborated to prepare nano-biocomposites using two nanoclays, montmorillonite (MMT) and sepiolite (Sep). The clays differ in geometries with MMT having sheet structure and Sep having fiber structure. The environment-friendly non-solvent based elaboration of P(3HB-co-4HB) in the presence of nanoclays allows for minimizing thermal degradation while improving the overall mechanical properties and thermal resistance of the final multiphase materials. The degree of improvement in the properties is found to be not only a function of the clay dispersion in the polymer matrix but also on the morphology/shape of the clay particles and interfacial polymer-clay interactions. It has been found that despite the higher aspect ratio of lamellar-type MMT clays, the fiber-like Sep clay has better stiffening properties arising mainly from the better polymer-clay interactions through the silanol groups along the length of the fiber. As a result of this increased "effective" aspect ratio of Sep, the properties of the Sep-based nano-biocomposites are greatly enhanced. The detailed analyses using various techniques (TGA, DSC, TEM, XRD, uniaxial tensile test) allows comparison and analysis of the structure-property relationships between MMT and Sep nano-biocomposites.