Zeta potential of alumina powders with different crystalline phases in simulated body fluids

Layer-by-layer assembly induced strong, hydrophobic and anti-bacterial TEMPO oxidized cellulose nanofibrils films for highly efficient UV-shielding and oil-water separation

Anti-ultraviolet material with cost-effectiveness, environmental friendliness, and multifunction is urgently needed to address the serious problem of ultraviolet radiation. However, traditional anti-ultraviolet products based on plastics are unsustainable and harmful to the environment. Herein, the cellulose films with a sandwich structure using a surface assembly technique were reported. Natural L-phenylalanine was grafted onto cellulose nanofibrils via amidation to enhance their UV-shielding property. To address the hydrophilic nature and limited mechanical strength of cellulose films, we employed octadecyltrichlorosilane and 4ARM-PEG-NH2 for hydrophobic coating and mechanical reinforcement, respectively. In addition to providing complete UV resistance in the wavelength range of 200-320 nm, sample OPT5 exhibited significantly improved tensile stress, Young's modulus, and toughness, measuring 174.09 MPa, 71.11 MPa, and 295.33 MJ/m3, respectively. Furthermore, due to the presence of antibacterial amine groups, the modified film demonstrated a satisfactory inhibitory effect on the growth of Escherichia coli and Bacillus subtilis. Compared to natural cellulose films, the hydrophobically modified material achieved a contact angle of up to 121.1°, which enabled efficient separation of oil-water mixtures with a maximum separation efficiency of 93.87 %. In summary, the proposed TOCNF-based UV-shielding film with multifunctionality holds great potential for replacing petrochemical-derived plastics and serving as an applicable and sustainable membrane material.

Synthesis and Characterization of Boehmite Particles Obtained from Recycling: Water Disinfection Application

We report on the synthesis of boehmite aluminum oxide hydroxide particles with lamellar structure (γ-AlO(OH)) obtained from the recycling of metallic can seals, with the addition of silver nanoparticles (Ag-NPs) reduced by Aloe Vera extract. X-ray diffractometry (XRD) confirmed the γ-phase, and scanning electron microscopy (SEM) showed the presence of Ag-NPs on the boehmite particle surface, confirming the efficiency of the synthesis to obtain the composite material. The samples were used to treat lake water, according to the Standard Methods for the Examination of Water and Wastewater. The results indicated that the elimination of total coliforms and Escherichia coli occurred, with excellent efficiency for the Ag-boehmite sample. The tests show the possibility of reuse (5×) of the sample, as it maintained the efficiency of disinfection for E. coli. The preparation, use, and reuse of boehmite obtained from metallic waste is a case of a circular economy, focused on sustainability and green chemistry.

Adsorption characteristics of bovine serum albumin onto alumina with a specific crystalline structure

Bone cement containing alumina particles with a specific crystalline structure exhibits the ability to bond with bone. These particles (AL-P) are mainly composed of delta-type alumina (δ-Al2O3). It is likely that some of the proteins present in the body environment are adsorbed onto the cement and influence the expression of its bioactivity. However, the effect that this adsorption of proteins has on the bone-bonding mechanism of bone cement has not yet been elucidated. In this study, we investigated the characteristics of the adsorption of bovine serum albumin (BSA) onto AL-P and compared them with those of its adsorption onto hydroxyapatite (HA), which also exhibits bone-bonding ability, as well as with those of adsorption onto alpha-type alumina (α-Al2O3), which does not bond with bone. The adsorption characteristics of BSA onto AL-P were very different from those onto α-Al2O3 but quite similar to those onto HA. It is speculated that BSA is adsorbed onto AL-P and HA by interionic interactions, while it is adsorbed onto α-Al2O3 by electrostatic attraction. The results suggest that the specific adsorption of albumin onto implant materials might play a role in the expression of the bone-bonding abilities of the materials.