Green extraction of biomass from waste goat bones for applications in catalysis, wastewater treatment, and water disinfection

The goal of this work is to recycle waste goat bones in an environmentally acceptable way and then recover them for vital applications as an adsorbent of hazardous pollutants from water, an antimicrobial agent, and a catalyst. Recycled goat bone crystals (RGB) were characterized via thermal gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM), transmittance electron microscope (TEM), and Fourier transform infrared spectroscopy (FTIR). TGA data revealed that the goat bones sample consists of approximately 29.30 % organic residue and 70.70 % hydroxyapatite. The crystalline size was 3.65 nm and the particle size was 5–10 nm as resulted from XRD analysis and TEM images, respectively. The FT-IR spectrum showed the presence of functional groups of hydroxyapatite and organic molecules. RGB is used as a heterogenous catalyst in multicomponent reactions for synthesizing several tetrahydrobenzo [b]pyrans by employing a one-pot, three-component reaction comprising aromatic aldehydes, cyclohexane-1,3‑dione, and malononitrile in water at room temperature with an excellent yield ≈ 90–98 %. Compared to earlier studies on the synthesis of 4H-pyrans, our technique offers a number of benefits, such as increased yields, eco-friendly conditions quicker reactions, and recyclable. The antimicrobial capacity of RGB has been evaluated and compared with that of organic residue and hydroxyapatite extracted from RGB using colony counting technique. The petri dish containing hydroxyapatite showed minimal growth of microbes with inhibitions of 82.1 % and 98.7 % for both bacteria and fungi growth, respectively. Additionally, RGB has been studied as an adsorbent for wastewater purification and showed high removal efficiency of crystal violet dye ≈ 99.15 % after 30 min under the optimum conditions. As a result of this work, the RGB can be used on a large scale as a cheap and a promising commercial catalyst, biosorbent, and antimicrobial agent.