Value-added materials recovered from waste bone biomass: technologies and applications

A review on hydroxyapatite fabrication: from powders to additive manufactured scaffolds

Hydroxyapatite (HA), the main inorganic bone component, is the most widely researched bioceramic for bone repair. This paper presents a comprehensive review of recent advancements in HA synthesis methods and their integration into additive manufacturing (AM) processes. Synthesis methodologies discussed include wet, dry, and biomimetic routes, emphasizing their impact on tailoring the physicochemical properties of HA for biomedical applications. The incorporation of dopants and additives during synthesis is explored for optimizing the mechanical, biological, and osteogenic characteristics of HA-based materials. Moreover, the evolution of AM technologies from conventional 3D printing to advanced 4D and 5D printing is detailed, covering material selection, process parameters, and post-processing strategies vital for fabricating intricate, patient-specific scaffolds, implants, and drug delivery systems utilizing HA. The review underscores the importance of achieving precise control over microstructure and porosity to mimic native tissue architectures accurately. Furthermore, emerging applications of HA-based constructs in tissue engineering, regenerative medicine, drug delivery, and orthopedic implants are discussed, highlighting their potential to address critical clinical needs. Despite the glimmer of hope provided by the advent and progress of such AM capabilities, several aspects need to be addressed to develop efficient HA-based bone substitutes, which are explored in detail in this review.

Cuttlefish-Bone-Derived Hybrid Composite Scaffolds for Bone Tissue Engineering

Current investigations into the fabrication of innovative biomaterials that stimulate cartilage development result from increasing interest due to emerging bone defects. In particular, the investigation of biomaterials for musculoskeletal therapies extensively depends on the development of various hydroxyapatite (HA)/sodium alginate (SA) composites. Cuttlefish bone (CFB)-derived composite scaffolds for hard tissue regeneration have been effectively illustrated in this investigation using a hydrothermal technique. In this, the HA was prepared from the CFB source without altering its biological properties. The as-developed HA nanocomposites were investigated through XRD, FTIR, SEM, and EDX analyses to confirm their structural, functional, and morphological orientation. The higher the interfacial density of the HA/SA nanocomposites, the more the hardness of the scaffold increased with the higher applied load. Furthermore, the HA/SA nanocomposite revealed a remarkable antibacterial activity against the bacterial strains such as E. coli and S. aureus through the inhibition zones measured as 18 mm and 20 mm, respectively. The results demonstrated a minor decrease in cell viability compared with the untreated culture, with an observed percentage of cell viability at 97.2% for the HA/SA nanocomposites. Hence, the proposed HA/SA scaffold would be an excellent alternative for tissue engineering applications.

Kinetics study and Py-GC-MS analysis of pyrolysis in chicken bone waste for sustainable utilisation in thermal conversion

Chicken bone waste is generated by the food service industry and individual households. The main issues in bone waste management are related to illegal discharge or high disposal costs. However, their valorisation raises great prospects towards the achievement of environmental sustainability and circular bioeconomy. In this study, chicken bone waste feedstocks were sourced from the fried chicken process (CBF) and purchased from one of the world's largest fast-food restaurant chains as well as from household waste (CBO). The feedstocks were enzymatically pretreated, in preparation to be subjected to further processes, and then sonicated, dried, and milled. The elemental analysis revealed that both CBF and CBO had similar carbon, hydrogen, and nitrogen contents (c.a. 28% C, 4.5% H and 5% N). Mineral analysis showed calcium and phosphorus as key components, with phosphorus increasing and calcium decreasing after pyrolysis due to thermal degradation of calcium carbonate. The pyrolysis results demonstrated significant differences in kinetic parameters and reactivity. CBF, derived from pressure frying, displayed a lower temperature for the initial decomposition peak and a higher rate of volatile release compared to CBO. The activation energy profiles showed that while both samples had similar average activation energies (approximately 201-202 kJ/mol), CBF exhibited higher reactivity and a faster release of volatiles (total reactivity index RMtot 0.0305), and higher CPI indices for all elementary steps, and higher pyrolysis stability indexes Rw. Pyrolysis of CBF and CBO was modelled by applying the isoconversional Friedman method with fit quality R2 > 0.999. Pyrolysis (Py-Gc-MS) of chicken bone at 500 °C and 700 °C indicated a dominance of hydrocarbons and nitrogen-containing compounds, with CBF having higher fatty acid content due to frying oil residues. These findings highlight the influence of cooking methods on the pyrolytic behaviour of chicken bone waste, providing valuable insights for optimizing biochar production and other applications involving organic waste pyrolysis.

A comprehensive review of bone char: Fabrication procedures, physicochemical properties, and environmental application

Bone waste from slaughtering is an abundant but underutilized resource. Promoting its exploitation can reduce the environmental burden and achieve energy recovery. Bone char, a solid material prepared by the thermochemical conversion of animal bone, has a unique and rich mesoporous structure and ionic polarity sites. It has shown great potential for application. This review aims to provide information about the thermochemical conversion method of recycling waste bone to fabricate bone char and, on its basis, to summarize comprehensive data on the physicochemical properties to provide direction and theoretical support for the tailored environmental remediation applications. Therefore, the authors first elucidated the various influencing effects (e.g., bone type, pyrolysis atmosphere and temperature, etc.) and modification treatments (physical and chemical methods) during the fabrication of bone char. Secondly, the physicochemical properties (including but not limited to pore structure, elemental composition, surface functional groups, pH and ash content, etc.) of bone char are comprehensively discussed for the first time. Further, the development process of bone char applied as adsorbents and catalytic supports for environmental remediation (decolorization of sugar liquor, drinking water defluoridation, removal of heavy metals and organic pollutants) is presented, revealing the behaviors and mechanisms of pollutant removal by bone char. Finally, the authors present the prospects and challenges of developing bone char into a green and sustainable environmentally friendly material.

Efficiency of chemically activated raw and calcined waste fish bone for adsorption of Cd (II) and Pb (II) from polluted water

Bone biochar is used as an adsorbent in water pollution control because of its high surface area and pore volumes. This study is attempting to prepare a low-cost adsorbent from waste fish bones by chemical activation and use it for the removal of Cd2+ and Pb2+ from polluted water. The preparation of fish bone adsorbents involved two methods. The first method includes the chemical activation of waste fish bone using different chemical activators (0.001 M HNO3, 0.1 M NaOH, 0.5% H2O2, and ethanol) (FB), while the second one includes the calcination of waste fish bone after the chemical activation at 873 K (FB-Hy). The synthesized fish bone adsorbent (FB) was characterized by electron microscopy (SEM), X-ray diffractometer (XRD), X-ray fluorescence (XRF), Brunauer–Emmett–Teller (BET) surface area, and Fourier transform infrared (FT-IR). The effectiveness of the prepared adsorbent (FB) in removing Pb and Cd was evaluated based on contact time, solution pH, solution temperature, initial metal concentration, and adsorbent dose. Metal concentrations were measured by atomic absorption spectroscopy. The results show that 0.1 M NaOH activation of bone waste (FB) is suitable for higher adsorption of Cd2+ and Pb2+ compared with other activators. The maximum adsorption of Pb and Cd with the FB adsorbent was 99.74 and 99.35%, respectively, at optimum conditions (pH 6.0, contact time 30 min, initial metal concentration 10 ppm, adsorbent dosage 0.1 g, and temperature at 328 K). The results of kinetic adsorption obeyed a pseudo-second-order model. Freundlich and Langmuir isotherms were applied, and the adsorption was found to fit well with the Langmuir model. This study ended with the success of preparing an eco-friendly and low-cost fish bone adsorbent from the waste fish bone and using it for the removal of Cd2+ and Pb2+ from polluted water.