Preparation Of Chicken Bone Char Under Different Pyrolysis Temperature And Their Adsorption Abilities For Heavy Metal

Nowadays, anthropogenic factors associated with industrial, urban, agriculture and recreational activities have let to increasing emissions of heavy metals to the environment. These heavy metals pose a potential risk to the environment and human health because they can harm aquatic organisms by digestion, then after bioaccumulation and biomaginification fuctions, they finally enter a quatic food chains that lead to humans. Therefore, the control and treatment of heavy mental pollution has become one of the most challenging problems in the world. The adsorption method is an effective and promising technology for heavy metal treatment, which possessing characteristics of widely material resourc es, high adsorption capacity, fast removal rate, and easily operation. The present study aim to utilization of chicken bone and their application in heavy metal polluted water treatment. Using chicken bone, a catering industry waste, as raw material to pre pare black chicken bone char under different pyrolysis temperature(500, 600 and 700?C). The materials were characterised by thermogravimetric analysis(TG-TDA), X-Ray diffraction analysis(XRD), BET, fourier transform infrared spectrometer(FT-IR) and Scanning electron microscope(SEM). This study details the effects of heat treatment temperature on the physical and chemical characteristics of the adsorbent prepared from chicken bone and their adsorption abilities for Cd(Ⅱ) and Cu(Ⅱ). The results were as follows:(1) According to the XRD analysis, BET and SEM Results, there are several microstructure changes of the chicken bone char pyrolized by raw material: the surface became roughly and formed layered structure with certain pits and grooves, the specific surface area and pore volume increased greatly. The main ingredient in chicken bone char is hydroxyapatite. The hydroxyapatite phase was stable up to 700 ?C and no decompositon phase was detected.(2) All the three types of chicken bone char can effectively remove Cd(Ⅱ) and Cu(Ⅱ) from water. Using Langmuir can better fitting the adsorption processes. The maximum adsorption capacity of CBC500, CBC600 and CBC700 was 91.69、88.48 and 69.18 mg/g for Cd(Ⅱ), and 81.33、74.8 and 67.76 mg/g for Cu(Ⅱ), respectively. The maximum adsorption capacity decreased with increasing pyrolysis temperature, and CBC500 performs better adsorption ability than CBC600 and CBC700.(3) The adsorption of chicken bone char was a spontaneous and endothermic process with mesoporous adsorbent characteristics and followed a second-order kinetics equation. HNO3 had better desorption performance of heavy metal compared to Ultrapure water and Na OH.(4)According to the FT-IR results, with the increase of pyrolysis temperature, some functional groups in the chicken bone char loss gradually. CBC500 had higher hydroxyl groups than CBC600 and CBC700. Th e C—H stretching vibration, C=O stretching bands for carboxyl, aldehydes, ketones and esters and C=O stretching vibration for amide were existed in CBC500 but disappeared or reduced accordingly in CBC600 and CBC700. Compare the FI-IR spectra of chicken bone char before and after Cd(Ⅱ) and Cu(Ⅱ) binding adsorption, it was clear that the main effect of active group were PO43- and hydroxyl groups, while the remaining carbon fu nctional groups(such as C—H, C=O) also played a supplementary role in the adsorption of heavy metals. This may be the reason that CBC500 perform s better adsorption ability than CBC600 and CBC700.