Preparation of cellulose-hydroxyapatite composites using 3D printing for biomedical applications

Abstract: Every year, around 140 million tons of synthetic polymers are produced worldwide. Because of their non-degradability in landfills, traditional plastics made with petroleum-based synthetic polymers have caused considerable environmental difficulties. Aware of the growing concern, the proactive approach involves the investigation of polymers derived from renewable and sustainable materials for the production of bioproducts. This strategy provides a viable and novel alternative for reducing greenhouse gas and hazardous emissions, increasing energy efficiency, and reducing the use of nonrenewable resources. As a result, much study has been conducted on numerous types of biopolymers, examining their characteristics and potential medical applications. The results of this research show that cellulose is the most used biopolymer thanks to its biodegradability and various biological properties. To improve these properties, it is desirable to combine cellulose with biomass which bears important biological properties. The choice was the use of Moroccan natural phosphate thanks to the important reserves of phosphate rocks in Morocco, for the preparation of hydroxyapatite and combining them with the prepared cellulose, and then the elaboration of HAp-Cellulose biocomposite, by the method of 3D printing. this biocomposite will be used in the biomedical field

Toxic heavy metals removal from river water using a porous phospho-calcic hydroxyapatite

The process of adsorption of copper ions on synthesized hydroxyapatites (p-HAp) by the wet route has been studied experimentally to make a comparison between the adsorption capacity of our porous phospho-calcic material and the phosphate hydroxyapatite. The specific surface of p-HAp was studied by BET, as well as the characterization of p-HAp by FTIR and XRD showed that the synthetic hydroxyapatite has an apatite phase of crystalline structure which is very interesting for the adsorption of metals. Heavy, the results of the adsorption study obtained that the mechanism of adsorption of Cu2+ ions was best described by the pseudo-second-order kinetic model and obeyed the linear models of Langmuir isotherms, continued that the adsorption is done in the surface area of p-HAp. Langmuir model parameters reveal that, the adsorption mechanism of Cu2+ is fit with this model. The pseudo-first-order and pseudo-second-order models were also used to determine the adsorption kinetic. The experimental data were well fitted by the pseudo-second-order model. Thermodynamic parameters showed that, the adsorption of Cu2+  ion onto the composite surface is a spontaneous and favored at neutral pH and at a temperature little higher than room temperature

Low-cost composites based on porous titania–apatite surfaces for the removal of patent blue V from water: Effect of chemical structure of dye

Hydroxyapatite/titania nanocomposites (TiHAp) were synthesized from a mixture of a titanium alkoxide solution and dissolution products of a Moroccan natural phosphate. The simultaneous gelation and precipitation processes occurring at room temperature led to the formation of TiHAp nanocomposites. X-ray diffraction results indicated that hydroxyapatite and anatase (TiO2) were the major crystalline phases. The specific surface area of the nanocomposites increased with the TiO2 content. Resulting TiHAp powders were assessed for the removal of the patent blue V dye from water. Kinetic experiments suggested that a sequence of adsorption and photodegradation is responsible for discoloration of dye solutions. These results suggest that such hydroxyapatite/titania nanocomposites constitute attractive low-cost materials for the removal of dyes from industrial textile effluent

Parameters influencing ciprofloxacin, ofloxacin, amoxicillin and sulfamethoxazole retention by natural and converted calcium phosphates

International audienceThe retention of four antibiotics, ciprofloxacin, ofloxacin, amoxicillin and sulfamethoxazole by a natural phosphate rock (francolite) was studied and compared with a converted hydroxyapatite powder. The maximum sorption capacities were found to correlate with the molecular weight of the molecules. The mechanisms of sorption depended mostly on the charge of the antibiotic whereas the kinetics of the process was sensitive to their hydrophobic/hydrophilic character. The two materials showed slightly distinct affinities for the various antibiotics but exhibited similar maximum sorption capacities despite different specific surface areas. This was mainly attributed to the more pronounced hydrophobic character of the francolite phase constituting the natural phosphate. These data enlighten that the retention properties of these mineral phases depend on a complex interplay between the inter-molecular and molecule-solid interactions. These findings are relevant to understand better the contribution of calcium phosphates in the fate and retention of antibiotics in soils

Porous hydroxyapatite-TiO

Titanium dioxide-hydroxyapatite nanopowders were prepared by the simultaneous gelation of a titanium alkoxide and precipitation of a redisolved natural phosphate mineral. Evolution of the crystallinity, porous features and surface reactivity of these powders as a function of Ti content and heating was studied. Optimal conditions were found for the preparation of a low-cost nanocomposite powder that was as effective as pure titania for the decolorization of methylene blue solutions

Porous hydroxyapatite-TiO2 nanocomposites from natural phosphates and their decolorization properties

Titanium dioxide-hydroxyapatite nanopowders were prepared by the simultaneous gelation of a titanium alkoxide and precipitation of a redisolved natural phosphate mineral. Evolution of the crystallinity, porous features and surface reactivity of these powders as a function of Ti content and heating was studied. Optimal conditions were found for the preparation of a low-cost nanocomposite powder that was as effective as pure titania for the decolorization of methylene blue solutions