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

Abstract

AbstractBone 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.