Characterization Of Fish Scale Extracted Hydroxyapatite And Adsorption Performance On Acid Fuchsin

With the rapid development of food industry,many by-products are produced in the food industry that cannot be consumed by humans or animals and have relatively low economic value,which have no processing value,are difficult to handle and are usually discarded in large quantities.The reuse of food waste is a hot research topic at present.Natural peptides,polysaccharides,proteins,calcium,biochar and hydroxyapatite(HAp)can be extracted from some food waste as well as various chemical materials and biological resources,which are widely used in various fields such as food,biomedicine and wastewater treatment.Currently,the extraction of natural hydroxyapatite usually requires high temperature heating and calcination,and the extraction time is also long.To address this problem,this study prepared fish scale extracted hydroxyapatite from grass carp fish scales by improving the method of extracting hydroxyapatite from fish scales that has been reported in the literature with different drying treatments.The extracted hydroxyapatite was characterized by scanning electron microscopy(SEM),nitrogen adsorption desorption isotherm(BET),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Fourier infrared transform spectroscopy(FT-IR),and comparative analysis of the extracted hydroxyapatite.Then,the adsorption capacity and mechanism of acidic magenta(AF)adsorption of fish scale extracted hydroxyapatite prepared by different drying methods were investigated.Finally,the dynamic adsorption capacity of fish scale hydroxyapatite was investigated.The main studies and conclusions obtained in this paper are mainly as follows.(1)The method of extracting hydroxyapatite from fish scales,which has been reported in the literature,was improved to shorten the extraction time and reduce the energy consumption.the SEM characterization results showed that the morphology of hydroxyapatite prepared by three drying methods was different,with freeze-dried fish scale hydroxyapatite(FD-HAp)showing needle-like accumulation on the surface,hot air-dried fish scale hydroxyapatite(HD-HAp)showing coral-like accumulation,and naturally air-dried fish scale The BET characterization results showed that the specific surface areas of the four HAp species were different,and the specific surface area of ND-HAp was the largest.the XRD characterization results showed that the characteristic peaks of fish scale extracted HAp were consistent with those of C-HAp and HAp standard,proving that The XPS characterization results showed that the main constituent elements of HAp were calcium,phosphorus and oxygen.FT-IR characterization results confirmed that the functional groups of the three HAp were consistent with those of C-HAp,which once again proved the successful extraction of fish scale hydroxyapatite.(2)The adsorption capacity and adsorption mechanism of fish scale HAp prepared by three different drying methods were investigated.The results of adsorption singlefactor experiments showed that FD-HAp possessed a high adsorption capacity at low concentrations.The adsorbent addition amount affected the adsorption capacity of fish scale HAp,and the addition amount of 5 mg could be used as a suitable adsorbent addition amount for subsequent experiments.The adsorption capacity of fish-scale HAp was highest at the adsorption temperature of 30℃.The experimental results of the effect of time on the adsorption capacity of fish scale HAp showed that the process of adsorption of AF by fish scale HAp was a rapid adsorption process.The results of ionic strength experiments showed that the adsorption capacity of fish scale HAp could still maintain high in the presence of NA+,Cl-ions interference.The quasi-secondary kinetic model fitted better with the process of AF adsorption by fish scale HAp.The results of the adsorption isotherms indicated that the Langmuir model had a better fit for the adsorption process of the three HAp.The maximum adsorption amounts of HAp could be calculated by the Langmuir model as FD-HAp: 1068.27 mg/g,HD-HAp:987.16 mg /The adsorption thermodynamic results showed that the process of AF adsorption by the three HAp was spontaneous exothermic.The drying mode changed the adsorption capacity by affecting the specific surface area of fish scale HAp,and a larger specific surface area could enable fish scale HAp to have a higher adsorption rate.The adsorption AF of fish scale HAp is mainly the result of the interaction between hydrogen bonding and electrostatic interactions.The adsorption capacity of fish scale HAp is good in the anionic system,and the influence of other interfering ions in the simulated wastewater on the adsorption AF of fish scale HAp is small,and the removal rate of fish scale HAp is still more than 50%after 3 cycles.(3)The experimental results of dynamic adsorption capacity showed that the adsorption efficiency of the adsorption column with 3m L capacity was better.The higher the amount of adsorbent added,the higher the removal rate of AF by fish scale HAp.The lower the initial concentration of the dye,the stronger the removal ability of acidic magenta.The reason for the effect is mainly the contact time between AF and fish scale HAp,the longer the contact time,the stronger the adsorption capacity.