氫氧基磷灰石(HA)是一種廣泛存在於自然界的材料，尤其是在生物礦物中，其為生物的硬組織提供了良好的強度以及環境，因此氫氧基磷灰石常被使用為骨骼或是牙齒的支架材料。除了生醫方面的用途，近年來氫氧基磷灰石的離子吸附特性逐漸受到重視。在過去用來作為吸附材料的氫氧基磷灰石多以人工合成，但人工合成的氫氧基磷灰石的成本較高，因此在本篇研究中我們提出使用台灣鯛魚(Oreochromis mossambicus)魚鱗中的氫氧基磷灰石作為原料，來大幅度地減少製造成本以及汙染，魚鱗中萃取的氫氧基磷灰石粉末經過X-ray 繞射儀及粒徑分析儀的評估後，便可用於後續吸附材的製程。此外，我們引進了冷凍鑄造技術，將魚鱗中萃取的氫氧基磷灰石粉與甲基聚醣(CS)相結合，形成一具有方向性的多孔塊材。此種新型多孔塊材可藉由調控冷卻速率形成不同大小的孔洞通道，其微結構也更進一步被掃描式電子顯微鏡(SEM)還有汞壓汞孔徑分佈儀確認，結果顯示此種塊材有著從10奈米到100微米的多階層孔洞。為了瞭解此種多孔複合材的可應用範圍，本實驗中採取了兩種不同的實驗設計，批量吸附(batch processing)以及固定床吸附(fixed-bed processing)，並使用原子吸收光譜(AAS)來確認鉛離子吸附的效率。結果也證實此種新型複合材具有相當卓越的鉛離子吸附能力，藉由在冷凍鑄造過程調控不同的孔徑大小，吸附的表現及可應用範圍也會有著相應的變化。綜言之，本研究從魚鱗中萃取的氫氧基磷灰石所製備之複合多孔塊材在吸附方面有著很好的潛力，可根據是否應用於流體、離子的初始濃度、處理所需的期望時間等因素，適當的改變通道大小，廣泛地被應用於汙水處理領域。

Hydroxyapatite (HA) is a widely known mineral in nature and provides mechanical support for hard tissues, such as bone and teeth. In addition, HA is highlighted as a remarkable green material with high ion removal ability nowadays. However, the source of HA in most studies on wastewater treatment is typically from synthesis, causing the comparatively higher cost and pollution. In this study, we proposed a new approach to obtain HA from Tilapia fish (Oreochromis mossambicus) scales. After cleaning and calcination, fish-scale extracted HA powder was further confirmed by X-ray diffraction (XRD) and particle size analyzer. Thereafter, fish-scale extracted HA powder was combined with chitosan (CS) to form an orderly porous composite by the freeze casting technique, and its microstructure and pore size distribution were further analyzed by SEM and mercury porosimetry. The result demonstrated that the channel size can be modified by controlling proper cooling rate during freeze casting process, and the pore size distribution ranged from 10nm-100μm, corresponding to the interspace of particles and laminar structures. Subsequently, the applicable field of HA/CS composite scaffold was further evaluated by both batch and fixed-bed processes, and the innovative scaffold demonstrated remarkable adsorption capability for lead ion. The adsorption amount was also quantified by the Atomic Absorption Spectrometer (AAS). By tuning the cooling rates during freeze casting, the adsorption behaviors of HA/CS porous composites were distinctly different and can be potentially applied in various fields.

Chapter 1. Introduction......................1
1.1. Background................................1
1.2. Goals.....................................3
Chapter 2. Literature Review.................4
2.1. Wastewater Treatment......................4
2.1.1. Carbon materials..........................4
2.1.2. Mineral materials.........................5
2.2. Hydroxyapatite............................7
2.2.1. Structure.................................7
2.2.2. Production................................8
2.2.3. Adsorption Characteristic.................9
2.2.4. Hydroxyapatite/Chitosan Composites.......10
2.3. Adsorption Analysis......................12
2.3.1. Isotherm.................................12
2.3.2. Rate Equation............................14
2.3.3. Complicate Sorption......................15
2.4. Porous Ceramic Materials.................18
2.4.1. Replica/Sacrificial templating...........18
2.4.2. Blowing..................................19
2.4.3. Aerogels.................................20
2.4.4. Freeze Casting...........................21
2.5. Freeze Casting...........................22
2.5.1. Fundamental Principles...................22
2.5.2. Preparation and Structure Control........25
2.5.3. Developments and Applications............27
Chapter 3. Experimental Methods.............41
3.1. Material Preparation.....................41
3.1.1. Hydroxyapatite (HA) Powder Preparation...41
3.1.2. Chitosan (CS) Solution Preparation.......42
3.1.3. HA/CS Slurry Preparation.................42
3.2. Synthesis of Scaffold....................43
3.2.1. Freeze Casting...........................43
3.2.2. Crosslinking Process.....................44
3.3. Characterizations........................46
3.3.1. Structural Characterization..............46
3.3.2. Pore Size Distribution...................47
3.3.3. Compressive Mechanical Testing...........47
3.3.4. Evaluation of Environmental Influence....47
3.4. Adsorption Experimental Design...........50
3.4.1. Batch Processing.........................50
3.4.2. Flame Atomic Adsorption Spectroscopy.....50
3.4.3. Rate Equation............................52
3.4.4. Isotherm.................................52
3.4.5. Fixed Bed Process........................52
Chapter 4. Results and Discussion...........59
4.1. Material Analysis........................59
4.1.1. Powder Analysis..........................59
4.1.2. Chitosan.................................60
4.2. Synthesis of Scaffolds...................61
4.2.1. Cooling Source of Freeze Casting.........61
4.2.2. Crosslinking Process.....................61
4.3. Characterizations........................65
4.3.1. Porosity.................................65
4.3.2. Cooling Rate and Pore Size Distribution..66
4.3.3. Compressive Mechanical Behavior..........67
4.3.4. Evaluation of Environmental Influence....68
4.4. Adsorption Experiment....................70
4.4.1. Batch Processing.........................70
4.4.2. Rate Equation............................74
4.4.3. Precipitation Analysis...................75
4.4.4. Isotherm.................................77
4.4.5. Fixed Bed Processing.....................79
Chapter 5. Conclusions......................114
References.......................................118

[1] X. Wen, C.-T. Shao, W. Chen, Y. Lei, Q.-F. Ke, and Y.-P. Guo, "Mesoporous carbonated hydroxyapatite/chitosan porous materials for removal of Pb(ii) ions under flow conditions," RSC Adv., vol. 6, pp. 113940-113950, 2016.
[2] S. Park, A. Gomez-Flores, Y. S. Chung, and H. Kim, "Removal of Cadmium and Lead from Aqueous Solution by Hydroxyapatite/Chitosan Hybrid Fibrous Sorbent: Kinetics and Equilibrium Studies," Journal of Chemistry, vol. 2015, pp. 1-12, 2015.
[3] Y. Yan, X. Dong, X. Sun, X. Sun, J. Li, J. Shen, et al., "Conversion of waste FGD gypsum into hydroxyapatite for removal of Pb(2)(+) and Cd(2)(+) from wastewater," J. Colloid. Interface. Sci., vol. 429, pp. 68-76, Sep 01 2014.
[4] I. Mobasherpour, E. Salahi, and M. Pazouki, "Comparative of the removal of Pb2+, Cd2+ and Ni2+ by nano crystallite hydroxyapatite from aqueous solutions: Adsorption isotherm study," Arabian Journal of Chemistry, vol. 5, pp. 439-446, 2012.
[5] G. Crini, "Recent developments in polysaccharide-based materials used as adsorbents in wastewater treatment," Progress in Polymer Science, vol. 30, pp. 38-70, 2005.
[6] S. J. T. Pollard, G. D. Fowler, C. J. Sollars, and R. Perry, "Low-cost adsorbents for waste and wastewater treatment a review.," The Science of the Total Environment, vol. 116, pp. 31-52, 1992.
[7] R. W. Coughlin and F. S. Ezra1, "Role of Surface Acidity in the Adsorption of Organic Pollutants," vol. 2, pp. 291-297, 1968.
[8] F. CATURLA, J. M. MARTIN-MARTINEZ, M. MOLINA-SABIO, F. RODRIGUEZ-REINOSO, and R. TORREGROSA, "Adsorption of substituted phenols on activated carbon," Colloid and Interface Science, vol. 124, pp. 528-534, 1987.
[9] R. Xie, H. Wang, Y. Chen, and W. Jiang, "Walnut shell-based activated carbon with excellent copper (II) adsorption and lower chromium (VI) removal prepared by acid-base modification," Environmental Progress & Sustainable Energy, vol. 32, pp. 688-696, 2013.
[10] A. K. SENGUPTA, "Ion exchange technology advances in pollution control," Adsorption, vol. 2, pp. 181-182, 1996.
[11] O. Altın, H. O. nder, O. zbelge, and T. Dog˘u, "Use of General Purpose Adsorption Isotherms for Heavy Metal–Clay Mineral Interactions," COLLOID AND INTERFACE SCIENCE, vol. 198, pp. 130-140, 1998.
[12] J. Peric, M. Trgo, and N. Vukojevic Medvidovic, "Removal of zinc, copper and lead by natural zeolite-a comparison of adsorption isotherms," Water Res, vol. 38, pp. 1893-9, Apr 2004.
[13] A. E. Osmanlioglu, "Treatment of radioactive liquid waste by sorption on natural zeolite in Turkey," J Hazard Mater, vol. 137, pp. 332-5, Sep 01 2006.
[14] M. Rasouli, N. Yaghobi, M. Hafezi, and M. Rasouli, "Adsorption of divalent lead ions from aqueous solution using low silica nano-zeolite X," Journal of Industrial and Engineering Chemistry, vol. 18, pp. 1970-1976, 2012.
[15] M. A. Meyers and P.-Y. Chen, "Biological Materials Science: Biological Materials, Bioinspired Materials, and Biomaterials " MRS Bulletin, vol. 40, pp. 612-613, 2015.
[16] K. A. SELVIG, "The crystal structure of hydroxyapatite in dental enamel as seen with the electron microscope," J. ULTRASTRUCTURE RESEARCH, vol. 41, pp. 369--375, 1972.
[17] E. D. Eanes, J. D. Termine, and M. U. Nylen, "An electron microscopic study of the formation of amorphous calcium phosphate and its transformation to crystalline apatite," Calcified Tissue Research, vol. 12, pp. 143--158, 1973.
[18] T. Kawasaki, M. Niikura, and Y. Kobayashi, "Fundamental study of hydroxyapatite high-performance liquid chromatography II. Experimental analysis on the basis of the general theory of gradient chromatography," Chromatography, vol. 515 pp. 125-148, 1990.
[19] T. KAWASAKI, M. NIIKURA, and Y. KOBAYASHI, "Fundamental study of hydroxyapatite high-performance liquid chromatography III. Direct experimental confirmation of the existence of two types of adsorbing surface on the hydroxyapatite crystal," Chromatography, vol. 515 pp. 91-123, 1990.
[20] C. Meneghini, M. C. Dalconi, Stefania Nuzzo, S. Mobilio, and R. H. Wenk||, "Rietveld Refinement on X-Ray Diffraction Patterns of Bioapatite in Human Fetal Bones," Biophysical Journal, vol. 84, pp. 2021-2029, 2003.
[21] H. E. Fekia, J. M. Savariaultb, and A. B. Salaha, "Structure refinements by the Rietveld method of partially substituted hydroxyapatite Ca9Na0.5(PO4)4.5(CO3)1.5(OH)2," Journal of Alloys and Compounds, vol. 287, pp. 114–120, 1999.
[22] M. Veiderma, K. Tõnsuaadu, R. Knubovets, and M. Peld, "Impact of anionic substitutions on apatite structure and properties," Journal of Organometallic Chemistry, vol. 690, pp. 2638-2643, 2005.
[23] A. Bouregba and A. Diouri, "Potential formation of hydroxyapatite in total blood and dicalcium silicate elaborated from shell and glass powders," Materials Letters, vol. 183, pp. 405-407, 2016.
[24] A. Deptuta, W. Lada, T. Olczak, A. Borello, C. Alvani, and A. d. Bartolomeo, "Preparation of spherical powders of hydroxyapatite by sol-gel process," Non-Crystalline Solids, vol. 147 & 148, pp. 537-541, 1992.
[25] G. K. Lim, J. Wang, S. C. Ng, and L. M. Gan, "Nanosized hydroxyapatite powders from microemulsions and emulsions stabilized by a biodegradable surfactant," Materials Chemistry, vol. 9, pp. 1635-1639, 1999.
[26] K. Ozeki, A. Mishima, T. Yuhta, Y. Fukui, and H. Aoki, "Bone bonding strength of sputtered hydroxyapatite films subjected to a low temperature hydrothermal treatment," Bio-Medical Materials and Engineering, vol. 13, pp. 451-463, 2003.
[27] S. Sugiyama and J. B. Moffat, "Cation Effects in the Conversion of Methanol on Calcium, Strontium, Barium and Lead Hydroxyapatites," Catalysis Letters vol. 81, pp. 77-81, 2002.
[28] Y. Li, H. Zhou, G. Zhu, C. Shao, H. Pan, X. Xu, et al., "High efficient multifunctional Ag3PO4 loaded hydroxyapatite nanowires for water treatment," J Hazard Mater, vol. 299, pp. 379-87, Dec 15 2015.
[29] A. Corami, S. Mignardi, and V. Ferrini, "Copper and zinc decontamination from single- and binary-metal solutions using hydroxyapatite," J. Hazard. Mater., vol. 146, pp. 164-70, Jul 19 2007.
[30] S. T. Ramesh, N. Rameshbabu, R. Gandhimathi, M. Srikanth Kumar, and P. V. Nidheesh, "Adsorptive removal of Pb(II) from aqueous solution using nano-sized hydroxyapatite," Applied Water Science, vol. 3, pp. 105-113, 2012.
[31] Z. Zhang, M. Li, W. Chen, S. Zhu, N. Liu, and L. Zhu, "Immobilization of lead and cadmium from aqueous solution and contaminated sediment using nano-hydroxyapatite," Environ. Pollut., vol. 158, pp. 514-9, Feb 2010.
[32] N. Gupta, A. K. Kushwaha, and M. C. Chattopadhyaya, "Adsorptive removal of Pb2+, Co2+ and Ni2+ by hydroxyapatite/chitosan composite from aqueous solution," Journal of the Taiwan Institute of Chemical Engineers, vol. 43, pp. 125–131, 2012.
[33] I. LANGMUIR, "THE ADSORPTION OF GASES ON PLANE SURFACES OF GLASS, MICA AND PLATINUM," J. Am. Chem. Soc., vol. 40, pp. 1361-1403, 1918.
[34] F. Herbert, "Über die Adsorption in Lösungen," Zeitschrift für Physikalische Chemie - Stöchiometrie und Verwandschaftslehre, vol. 57, pp. 385-470, 1907.
[35] L. S., "Zur theorie der sogenannten adsorption gelo¨ sterstoffe," Kungliga Svenska Vetenskapsakademiens Handlingar, vol. 24, pp. 1–39, 1898.
[36] Y. S. Ho and G. McKay, "Pseudo-second order model for sorption processes," Process Biochemistry, vol. 34, pp. 451-465, 1999.
[37] M. Al-Jabari, "Kinetic mass transfer adsorption model for treating dairy wastewater with stone cutting solid waste," Environmental Technology & Innovation, vol. 7, pp. 21-29, 2017.
[38] M. S. Shafeeyan, W. M. A. Wan Daud, and A. Shamiri, "A review of mathematical modeling of fixed-bed columns for carbon dioxide adsorption," Chemical Engineering Research and Design, vol. 92, pp. 961-988, 5// 2014.
[39] D. M. Ruthven, "Principles of adsorption and adsorption processes," John Wiley and Sons Ltd., 1984.
[40] R. T. Yang, "Gas Separation by Adsorption Processes," Butterworth, Boston., 1987.
[41] H. D. Do and D. D. Do, "Maxwell–Stefan analysis of multicomponent transient diffusion in a capillary and adsorption of hydrocarbons in activated," Chemical Engineering Science, vol. 53, pp. 1239-1252, 1998.
[42] M. Gholami and M. R. Talaie, "Investigation of Simplifying Assumptions in Mathematical Modeling of Natural Gas Dehydration Using Adsorption Process and Introduction of a New Accurate LDF Model," Ind. Eng. Chem. Res., vol. 49, pp. 838-846, 2010.
[43] M. Khalighi, S. Farooq, and I. A. Karimi, "Nonisothermal Pore Diffusion Model for a Kinetically Controlled Pressure Swing Adsorption Process," Industrial & Engineering Chemistry Research, vol. 51, pp. 10659-10670, 2012.
[44] C. Vakifahmetoglu, D. Zeydanli, and P. Colombo, "Porous polymer derived ceramics," Materials Science and Engineering: R: Reports, vol. 106, pp. 1-30, 2016.
[45] K. Schwartzwalder and A. V. Somers, "METHOD OF MAKING POROUS CERAMIC ARTICLES," US Pat. No. 3090094, 1963.
[46] A. R. Studart, U. T. Gonzenbach, E. Tervoort, and L. J. Gauckler, "Processing Routes to Macroporous Ceramics: A Review," Journal of the American Ceramic Society, vol. 89, pp. 1771-1789, 2006.
[47] I. John Wiley & Sons, "Innovative Processing and Manufacturing of Advanced Ceramics and Composites II Ceramic Transactions," The American Ceramic Society, vol. 243, pp. 49-62, 2014.
[48] C. Voigt, E. Jäckel, F. Taina, T. Zienert, A. Salomon, G. Wolf, et al., "Filtration Efficiency of Functionalized Ceramic Foam Filters for Aluminum Melt Filtration," Metallurgical and Materials Transactions B, vol. 48, pp. 497-505, 2016.
[49] U. T. Gonzenbach, A. R. Studart, E. Tervoort, and L. J. Gauckler, "Macroporous Ceramics from Particle-Stabilized Wet Foams," Journal of the American Ceramic Society, vol. 90, pp. 16-22, 2007.
[50] E. Zera, R. Campostrini, P. R. Aravind, Y. Blum, and G. D. Sorarù, "Novel SiC/C Aerogels Through Pyrolysis of Polycarbosilane Precursors," Advanced Engineering Materials, vol. 16, pp. 814-819, 2014.
[51] Y. Kong, X. Shen, S. Cui, and M. Fan, "Preparation of monolith SiC aerogel with high surface area and large pore volume and the structural evolution during the preparation," Ceramics International, vol. 40, pp. 8265-8271, 2014.
[52] S. Deville, E. Saiz, R. K. Nalla, and A. P. Tomsia, "Freezing as a Path to Build Complex Composites," Science, vol. 311, pp. 515-518, 2006.
[53] E. Munch, M. E. Launey, D. H. Alsem, E. Saiz, A. P. Tomsia, and R. O. Ritchie, "Tough, Bio-Inspired Hybrid Materials," Science, vol. 322, pp. 1516-1520, 2008.
[54] S. Deville, "Freeze-Casting of Porous Ceramics: A Review of Current Achievements and Issues," Advanced Engineering Materials, vol. 10, pp. 155-169, 2008.
[55] U. G. Wegst, M. Schecter, A. E. Donius, and P. M. Hunger, "Biomaterials by freeze casting," Philos. Trans. A. Math. Phys. Eng. Sci., vol. 368, pp. 2099-121, Apr 28 2010.
[56] H. Zhang, I. Hussain, M. Brust, M. F. Butler, S. P. Rannard, and A. I. Cooper, "Aligned two- and three-dimensional structures by directional freezing of polymers and nanoparticles," Nat Mater, vol. 4, pp. 787-93, Oct 2005.
[57] R. ASTHANA and S. N. TEWARI, "The engulfment of foreign particles by a freezing interface," MATERIALS SCIENCE, vol. 28, pp. 5414-5425, 1993.
[58] D. R. Uhlmann, B. Chalmers, and K. A. Jackson, "Interaction Between Particles and a Solid‐Liquid Interface," Journal of Applied Physics, vol. 35, pp. 2986-2993, 1964.
[59] C. KORBER, G. RAU, M. D. COSMAN, and E. G. CRAVALHO, "Interaction of particles and a moving ice-liquid interface," Crystal Growth, vol. 72 pp. 649-662, 1985.
[60] G. F. BOLLING and J. CISSE, "A theory for the interaction of particles with a solidifying front," Crystal Growth vol. 10, pp. 56-66, 1971.
[61] D. M. STEFANESCU, B. K. DHINDAW, S. A. KACAR, and A. MOITRA, "Behavior of ceramic particles at the solid- liquid metal interface in metal matrix composites," METALLURGICAL TRANSACTIONS A, vol. 19, pp. 2847-2855, 1988
[62] W. A. Maxwell, R. S. Gurnick, and A. C. Francisco, "Preliminary Investigation of the 'freeze-casting' Method for Forming Refractory Powders," NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS, 1954.
[63] S. W. Sofie and F. Dogan, "Freeze Casting of Aqueous Alumina Slurries with Glycerol," the American Ceramic Society, vol. 84 pp. 1459-64, 2001.
[64] Y. Chino and D. C. Dunand, "Directionally freeze-cast titanium foam with aligned, elongated pores," Acta Materialia, vol. 56, pp. 105-113, 2008.
[65] S. Deville, E. Saiz, and A. P. Tomsia, "Freeze casting of hydroxyapatite scaffolds for bone tissue engineering," Biomaterials, vol. 27, pp. 5480-9, Nov 2006.
[66] Q. Fu, M. N. Rahaman, F. Dogan, and B. S. Bal, "Freeze casting of porous hydroxyapatite scaffolds. I. Processing and general microstructure," J Biomed Mater Res B Appl Biomater, vol. 86, pp. 125-35, Jul 2008.
[67] H. M. Tong and C. C. Gryte, "Mechanism of lamellar spacing adjustment in directionally frozen agar gels," Colloid & Polymer Science, vol. 263, pp. 147-155, 1985.
[68] H. Schoof, L. Bruns, A. Fischer, I. Heschel, and G. Rau, "Dendritic ice morphology in unidirectionally solidified collagen suspensions," Crystal Growth vol. 209, pp. 122-129, 2000.
[69] H. Bai, F. Walsh, B. Gludovatz, B. Delattre, C. Huang, Y. Chen, et al., "Bioinspired Hydroxyapatite/Poly(methyl methacrylate) Composite with a Nacre-Mimetic Architecture by a Bidirectional Freezing Method," Adv. Mater., vol. 28, pp. 50-6, Jan 06 2016.
[70] L. L. da Silva and F. Galembeck, "Morphology of latex and nanocomposite adsorbents prepared by freeze-casting," J. Mater. Chem. A, vol. 3, pp. 7263-7272, 2015.
[71] E. Salehi, P. Daraei, and A. Arabi Shamsabadi, "A review on chitosan-based adsorptive membranes," Carbohydr Polym, vol. 152, pp. 419-32, Nov 05 2016.
[72] E. Guibal, "Interactions of metal ions with chitosan-based sorbents: a review," Separation and Purification Technology, vol. 38, pp. 43-74, 2004.
[73] R. A. A. Muzzarelli, F. T. and, and M. Emanuelli, "Chelating derivatives of chitosan obtained by reaction with ascorbic acid," Carbohydrate Polymers, vol. 4, pp. 137-151, 1984.
[74] K. Ogawa and K. Oka, "X-ray Study of Chitosan-Transition Metal Complexes," Chem. Mater, vol. 5, pp. 726-728, 1993.
[75] C. Liu, R. Bai, and L. Nan, "Sodium Tripolyphosphate (TPP) Crosslinked Chitosan Membranes and Application in Humic Acid Removal," Revista Facultad de Ingenieria. Universidad de Antioquia, pp. 38-47, 2016.
[76] W.-K. Liu, B.-S. Liaw, H.-K. Chang, Y.-F. Wang, and P.-Y. Chen, "From Waste to Health: Synthesis of Hydroxyapatite Scaffolds From Fish Scales for Lead Ion Removal," JOM, vol. 69, pp. 713-718, 2017.
[77] X. Y. Zhao, Y. J. Zhu, J. Zhao, B. Q. Lu, F. Chen, C. Qi, et al., "Hydroxyapatite nanosheet-assembled microspheres: hemoglobin-templated synthesis and adsorption for heavy metal ions," J. Colloid. Interface. Sci., vol. 416, pp. 11-8, Feb 15 2014.
[78] Y. Yan, Y. Wang, X. Sun, J. Li, J. Shen, W. Han, et al., "Optimizing production of hydroxyapatite from alkaline residue for removal of Pb2+ from wastewater," Applied Surface Science, vol. 317, pp. 946-954, 2014.
[79] F. Googerdchian, A. Moheb, R. Emadi, and M. Asgari, "Optimization of Pb(II) ions adsorption on nanohydroxyapatite adsorbents by applying Taguchi method," J Hazard Mater, vol. 349, pp. 186-194, May 5 2018.
[80] Q. Shen, L. Luo, L. Bian, Y. Liu, B. Yuan, C. Liu, et al., "Lead cations immobilization by hydroxyapatite with cotton-like morphology," Journal of Alloys and Compounds, vol. 673, pp. 175-181, 2016.
[81] M. Aliabadi, M. Irani, J. Ismaeili, and S. Najafzadeh, "Design and evaluation of chitosan/hydroxyapatite composite nanofiber membrane for the removal of heavy metal ions from aqueous solution," Journal of the Taiwan Institute of Chemical Engineers, vol. 45, pp. 518-526, 2014.
[82] S. Saber-Samandari, S. Saber-Samandari, N. Nezafati, and K. Yahya, "Efficient removal of lead (II) ions and methylene blue from aqueous solution using chitosan/Fe-hydroxyapatite nanocomposite beads," J. Environ. Manage., vol. 146, pp. 481-490, Dec 15 2014.
[83] A. M. Mohammad, T. A. Salah Eldin, M. A. Hassan, and B. E. El-Anadouli, "Efficient treatment of lead-containing wastewater by hydroxyapatite/chitosan nanostructures," Arabian Journal of Chemistry, vol. 10, pp. 683-690, 2017.
[84] A. Khawar, Z. Aslam, A. Zahir, I. Akbar, and A. Abbas, "Synthesis of Femur extracted hydroxyapatite reinforced nanocomposite and its application for Pb(II) ions abatement from aqueous phase," Int J Biol Macromol, vol. 122, pp. 667-676, Feb 1 2019.
[85] J. Oliva, J. De Pablo, J. L. Cortina, J. Cama, and C. Ayora, "The use of Apatite II to remove divalent metal ions zinc(II), lead(II), manganese(II) and iron(II) from water in passive treatment systems: column experiments," J. Hazard. Mater., vol. 184, pp. 364-74, Dec 15 2010.
[86] Y. Lei, J.-J. Guan, W. Chen, Q.-F. Ke, C.-Q. Zhang, and Y.-P. Guo, "Fabrication of hydroxyapatite/chitosan porous materials for Pb(ii) removal from aqueous solution," RSC Advances, vol. 5, pp. 25462-25470, 2015.