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Novel Chitosan / Polyester Crosslinked Spheres for Adsorption of Heavy Metal Ions (Pb+2)

المؤلف الرئيسي: Ekrayem, Nooraddein Ali (Author)
مؤلفين آخرين: Amer, Mohamed M. (Advisor)
التاريخ الميلادي: 2018
موقع: طرابلس
الصفحات: 1 - 86
رقم MD: 1018672
نوع المحتوى: رسائل جامعية
اللغة: الإنجليزية
الدرجة العلمية: رسالة ماجستير
الجامعة: جامعة طرابلس
الكلية: كلية الهندسة
الدولة: ليبيا
قواعد المعلومات: +Dissertations
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المستخلص: Heavy metals are one of the most toxic materials to the environment. Adsorption is the most technique that has been widely used for the removal of heavy metals from wastewater due to many advantages including high efficiency, low cost, and wide range of working conditions. Many researches have been conducted to remove heavy metals using different materials. Various adsorbents have been used to remove different type of heavy metal ions. Activated carbons, starch, genipin, plant or lingo cellulosic wastes and biopolymers are the most common adsorbents used. For this research, chitosan was used as a adsorbent to remove Lead Pb2+ from wastewater. Chitosan is a polar biopolymer with good physical properties and have unique chemical interactions due to the presence of (NH2) and hydroxyl (-OH) functional groups that can easily react with various groups. Neat chitosan spheres retain the solubility in dilute acids; therefore, it lacks to be used in various applications. This solubility is typically overcome by presence of crosslinking. A conventional chitosan crosslinking reaction involves dialdehydes, diethers or epoxides. In this study, chitosan spheres were crosslinked with polyesters-based cross-linker agents. A novel class of crosslinked biomacromolecule spheres has been prepared from chitosan (CTS), and maleic anhydride-based polyester. Two polyesters were synthesized from maleic anhydride (MA), 1,4-butadiol (But) and (MA), (But) and glycerine (Gly). The structures of the esters (MA-But) and (MA-But-Gly) were confirmed by Fourier transform infrared spectroscopy (FT-IR). The reaction between primary amine in CTS and carboxylic acid in polyester forming amid bond was confirmed using FTIR. In particular, the stability of CTSbased spheres was significantly enhanced with crosslinking in aqueous media. Batch experiments were conducted to obtain the optimum conditions for Pb2+. Effect of adsorption parameter like pH, contact time, temperature and initial metal ion concentration were also determined. The optimum conditions obtained were 420 min contact time, 17.4 mg adsorbent dose and pH 5 for Pb2+. Adsorption behavior could be described using the Langmuir, Freundlich and Temkin isotherm model. Adsorption data was well fitted the Langmuir isotherm model for metal. The maximum adsorption capacity was found to be 20 mg/g for Pb2+. The kinetics of adsorption could describe using pseudo first order and pseudo second order kinetic model. In all cases the kinetics follow the pseudo second order rate equation. Also, the thermodynamic parameter (ΔG˚, ΔH˚ and ΔS˚) have been calculation for all system.

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