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

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.