Call number: LD2668 .T4 1986 K86 / Master of Science / Civil Engineering

Call number: LD2668 .T4 1986 L39 / Master of Science / Agronomy

M.Sc., Faculty of Science, University of the Witwatersrand, 2011 / Contamination of water bodies by heavy metals and metalloids is an established problem and several studies have been conducted to deal with it. South Africa is amongst those countries whose water systems are most affected as a result of intensive mining activities. This research was dedicated to the development of insoluble chelating polymers for use as adsorbents to abstract heavy metal ions from mining and industrial wastewater. Branched polyethylenimine (PEI), well known for its metal chelating potential, was cross linked by epichlorohydrin in order to convert it into a water-insoluble form. The water-insoluble property gives the advantage of being used in situ and a possibility of regeneration and re-use, making it a more feasible and cost-effective method. Its surface was also modified for selective removal of specifically-targeted heavy metal and metalloid ions. The binding affinity of the synthesized materials to heavy metal and metalloid ions has been determined as well as their ability to be regenerated for reuse. These processes demonstrated that cross-linked polyethylenimine (CPEI) exhibited good complexation ability with high affinity to Cr and some divalent metal ions such as Fe, Zn, and Ni. On the other hand, it showed very poor ability to bind oxo-anions such as SeO32- and AsO2- which has been attributed to the unavailability of suitable functional groups to interact with these ions. The observed order of complexation was: Cr > Zn> Fe >> Ni > Mn > Pb >> As > U > Se. The phosphonated polyethylenimine (PCPEI) showed high selectivity for As, Mn and uranyl ions. The observed order of removal was: U > Mn> Ni > Zn > As >> Cr > Pb > Fe >> Hg > Se; whereas the suffocated polyethylenimine (SCPEI) exhibited high affinity to Se, and Hg. The observed order of adsorption was: Hg > Se >> U > Zn >Pb > Ni >> As > Cr > Fe. v The adsorption behaviour of these polymeric materials involved more than one mechanism such as complexation, normal surface charge exchange, and anion replacement and all these mechanisms are governed by the functional groups. The nitrogen atom on the chelating group (-NH) in the cross-linked polyethylenimine; the phosphorus atom on the chelating group (-PO3H2) in phosphonated cross-linked polyethylenimine; and sulphur atom on the chelating group (-SO3H) in suffocated cross-linked polyethylenimine act as Lewis bases and donate electrons to metal cations which are considered Lewis acids. The existence of the chelating groups in SCPEI and PCPEI facilitate the removal of oxo-anions through anion replacement since they exist as bases in solution and hence cannot be electron acceptors. Thus, the expected mechanism is the normal anion replacement. This mechanism can explain the high removal of Se by SCPEI since Se has similar chemical behaviour as sulphur and are in the same group in the periodic table. As such they can easily replace each other. Sulphur is released from the polymer into the solution by replacing the selenium ions in the polymer. Similar behaviour occurs between phosphorus in PCPEI and arsenic ions as As and P belong to the same group in the periodic table and hence have similarities in their chemical behaviour. The Langmuir and Freundlich isotherm models were used to interpret the adsorption nature of the metal ions onto synthesized polymers. The Freundlich isotherm was found to best fit and describe the experimental data describing the adsorption process of metal and metalloid ions onto the synthesized polymeric materials The kinetic rates were modelled using the pseudo first-order equation and pseudo second-order equation. The pseudo second-order equation was found to explain the adsorption kinetics most effectively implying chemisorption. vi The thermodynamic study of the adsorption of metals and metalloids by the synthesized CPEI, PCPEI and SCPEI resulted in high activation energies > 41 KJ mol-1 which confirm chemisorption as a mechanism of interaction between adsorbate and adsorbent. So far, the developed polymeric materials showed good results and have potential to be applied successfully for remediation of heavy metal-polluted waters, and they have potential for use in filter systems for household use in communities that use borehole water impacted by mining and industrial waste waters. The desorbed metals can be of use to metal processing industries.

Chan Sze-Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 65-73). / Abstracts in English and Chinese. / Acknowledgment --- p.i / Table of Contents --- p.ii / Abstract --- p.v / Abstract (Chinese Version) --- p.vi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Molybdenum in the Environment --- p.1 / Chapter 1.1.1 --- General Chemistry of Molybdenum --- p.1 / Chapter 1.1.2 --- Molybdenum in Animals and Plants --- p.1 / Chapter 1.1.3 --- Uses of Molybdenum Compounds --- p.3 / Chapter 1.2 --- Inductively Coupled Plasma Atomic Emission Spectrometry --- p.4 / Chapter 1.2.1 --- Principle of ICP-AES --- p.4 / Chapter 1.2.2 --- Inductively Coupled Plasma Emission Source --- p.5 / Chapter 1.2.3 --- Optical System --- p.6 / Chapter 1.2.4 --- Advantages of ICP-AES --- p.7 / Chapter 1.2.5 --- Disadvantages of ICP-AES --- p.8 / Chapter 1.3 --- Preconcentration Method --- p.9 / Chapter 1.4 --- Polysiloxane --- p.11 / Chapter 1.4.1 --- Introduction of Silica-gel --- p.11 / Chapter 1.4.2 --- Introduction of Sol-gel Processes --- p.13 / Chapter 1.4.3 --- Hybrid Inorganic-organic Sol-gel Materials --- p.14 / Chapter 1.4.4 --- Advantages Using Sol-gel Preparation of Organomodified Silica --- p.16 / Chapter 1.5 --- Chelating Resin --- p.19 / Chapter 1.6 --- Scope of Work --- p.21 / Chapter Chapter 2 --- Experimental --- p.22 / Chapter 2.1 --- Apparatus and Instrument --- p.22 / Chapter 2.2 --- Chemicals --- p.24 / Chapter 2.3 --- Samples --- p.25 / Chapter 2.4 --- Procedures --- p.26 / Chapter 2.4.1 --- Preparation of Diethylenetriaminetetraacetic-acid Functionalized Polysiloxane --- p.26 / Chapter 2.4.1.1 --- Preparation of Silica Precursor --- p.26 / Chapter 2.4.1.2 --- Functionalization with Diethylenetriamine --- p.27 / Chapter 2.4.1.3 --- Carboxymethylation of the amine groups of the Polysiloxane --- p.28 / Chapter 2.4.2 --- Preconcentration and Determination of Molybdenum --- p.29 / Chapter 2.4.2.1 --- Optimum pH for Adsorption --- p.29 / Chapter 2.4.2.2 --- Amount of Polysiloxane Required for Sorption of Trace Amount of Molybdenum --- p.29 / Chapter 2.4.2.3 --- Equilibrium Time --- p.30 / Chapter 2.4.2.4 --- Total Adsorption Capacity --- p.30 / Chapter 2.4.2.5 --- Adsorption Isotherm of Molybdenum --- p.30 / Chapter 2.4.2.6 --- Desorption Studies --- p.31 / Chapter 2.4.2.7 --- Effect of Foreign Ions on Preconcentration --- p.31 / Chapter 2.4.2.8 --- Preparation of the Mini-column --- p.32 / Chapter 2.4.2.9 --- Effect of Flow Rate --- p.33 / Chapter 2.4.2.10 --- Reusability of the Mini-column --- p.33 / Chapter 2.4.2.11 --- Preconcentration Factor and Detection Limit --- p.33 / Chapter 2.4.2.12 --- Determination of Mo(VI) in Seawater by ICP-AES --- p.33 / Chapter Chapter 3 --- Results and Discussion --- p.35 / Chapter 3.1 --- Characterization of Diethylenetriaminetetraacetic-acid Functionalized Polysiloxane --- p.35 / Chapter 3.2 --- pH Dependence of Mo(VI) Ion Uptake --- p.44 / Chapter 3.3 --- Amount of Polysiloxane Required for Adsorption of Trace Amount of Mo(VI) --- p.45 / Chapter 3.4 --- Equilibrium Time --- p.46 / Chapter 3.5 --- Total Adsorption Capacity --- p.47 / Chapter 3.6 --- Adsorption Isotherm of Molybdenum --- p.48 / Chapter 3.7 --- Desorption Studies --- p.54 / Chapter 3.8 --- Effect of Foreign Ions on Preconcentration --- p.55 / Chapter 3.9 --- Effect of Flow Rate on the Recovery of Mo(VI) --- p.57 / Chapter 3.10 --- Reusability of the Column --- p.58 / Chapter 3.11 --- Preconcentration Factor --- p.59 / Chapter 3.12 --- Detection Limit --- p.59 / Chapter 3.13 --- Accuracy --- p.60 / Chapter 3.14 --- Determination of Mo(VI) in Seawater Samples --- p.61 / Chapter 3.15 --- Precision --- p.62 / Chapter Chapter 4 --- Conclusion --- p.63 / Chapter Chapter 5 --- References --- p.65

by Chan Chui Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 83-94). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / 摘要 --- p.iii / Contents --- p.iv / List of Figures --- p.ix / List of Plates --- p.xi / List of Tables --- p.xii / List of Abbreviations --- p.xiv / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Di(2-ethylhexyl)phthalate (DEHP) --- p.1 / Chapter 1.1.1 --- The chemical class of DEHP: Phthalate ester --- p.1 / Chapter 1.1.2 --- Characteristics of DEHP --- p.3 / Chapter 1.1.3 --- Sources of releases and environmental concentration --- p.4 / Chapter 1.1.4 --- Persistence of DEHP --- p.5 / Chapter 1.1.5 --- Routes of exposure --- p.6 / Chapter 1.1.6 --- Toxicity of DEHP --- p.7 / Chapter 1.1.6.1 --- Acute toxicity --- p.7 / Chapter 1.1.6.2 --- Chronic toxicity --- p.8 / Chapter 1.1.6.2.1 --- Adverse effects on reproduction system --- p.8 / Chapter 1.1.6.2.2 --- Carcinogenicity --- p.9 / Chapter 1.1.6.2.3 --- Developmental toxicity --- p.9 / Chapter 1.1.6.2.4 --- Endocrine disruption --- p.10 / Chapter 1.1.6.2.5 --- Hepatotoxicity --- p.10 / Chapter 1.1.7 --- Regulations --- p.10 / Chapter 1.2 --- Treatment of DEHP --- p.11 / Chapter 1.2.1 --- Conventional treatment technologies --- p.11 / Chapter 1.2.1.1 --- Physical method --- p.11 / Chapter 1.2.1.1.1 --- Adsorption --- p.11 / Chapter 1.2.1.1.2 --- Sonolysis --- p.12 / Chapter 1.2.1.2 --- Photochemical method --- p.13 / Chapter 1.2.1.2.1 --- Photocatalytic oxidation (PCO) --- p.13 / Chapter 1.2.1.3 --- Biological method --- p.13 / Chapter 1.2.1.3.1 --- Biodegradation --- p.13 / Chapter 1.2.1.3.2 --- Sewage treatment process --- p.14 / Chapter 1.2.2 --- Integrated treatment method in the present study --- p.15 / Chapter 1.2.2.1 --- Biosorption --- p.15 / Chapter 1.2.2.1.1 --- Definition of biosorption --- p.15 / Chapter 1.2.2.1.2 --- Advantages of biosorption --- p.16 / Chapter 1.2.2.1.3 --- Chitinous materials as biosorbents --- p.16 / Chapter 1.2.2.1.4 --- Advantages of using chitinous materials as biosorbents --- p.17 / Chapter 1.2.2.1.5 --- Modeling of biosorption --- p.19 / Chapter 1.2.2.2 --- PCO --- p.21 / Chapter 1.2.2.2.1 --- Definition of PCO --- p.21 / Chapter 1.2.2.2.2 --- Mechanism of PCO --- p.23 / Chapter 1.2.2.2.3 --- Advantages of PCO --- p.25 / Chapter 2 --- Objectives --- p.27 / Chapter 3 --- Materials and methods --- p.28 / Chapter 3.1 --- Materials --- p.28 / Chapter 3.1.1 --- Adsorbate --- p.28 / Chapter 3.1.2 --- Biosorbents --- p.28 / Chapter 3.1.2.1 --- Pretreatment of biosorbents --- p.29 / Chapter 3.1.3 --- Photocatalytic reactor --- p.29 / Chapter 3.1.4 --- Photocatalyst --- p.30 / Chapter 3.1.5 --- Electron scavenger --- p.31 / Chapter 3.2 --- Methods --- p.31 / Chapter 3.2.1 --- Determination of DEHP concentration --- p.31 / Chapter 3.2.2 --- Batch biosorption experiment --- p.32 / Chapter 3.2.2.1 --- Screening of biosorbents --- p.33 / Chapter 3.2.2.2 --- Optimization of biosorption conditions --- p.33 / Chapter 3.2.2.2.1 --- Effect of biosorbent concentration --- p.33 / Chapter 3.2.2.2.2 --- Effect of initial pH --- p.33 / Chapter 3.2.2.2.3 --- Effect of biosorption time --- p.34 / Chapter 3.2.2.2.4 --- Effect of temperature --- p.34 / Chapter 3.2.2.2.5 --- Effect of agitation rate --- p.34 / Chapter 3.2.2.2.6 --- Effect of initial DEHP concentration --- p.34 / Chapter 3.2.2.2.7 --- "Combinational effect of initial pH, chitin A concentration and initial DEHP concentration" --- p.35 / Chapter 3.2.3 --- Extraction of adsorbed DEHP from chitin A --- p.35 / Chapter 3.2.3.1 --- Screening of extraction agents --- p.36 / Chapter 3.2.3.2 --- Determination of extraction time --- p.36 / Chapter 3.2.4 --- Batch PCO experiment --- p.36 / Chapter 3.2.4.1 --- Optimization of PCO conditions --- p.38 / Chapter 3.2.4.1.1 --- Effect of reaction time --- p.38 / Chapter 3.2.4.1.2 --- Effect of UV-A intensity --- p.38 / Chapter 3.2.4.1.3 --- Effect of TiO2 concentration --- p.38 / Chapter 3.2.4.1.4 --- Effect of H2O2 concentration --- p.38 / Chapter 3.2.4.1.5 --- Effect of initial pH --- p.39 / Chapter 3.2.4.1.6 --- Combinational effect of H2O2 concentration and initial pH --- p.39 / Chapter 3.2.4.1.7 --- Effect of concentration factor --- p.39 / Chapter 3.2.4.2 --- Identification of intermediates/products of DEHP --- p.39 / Chapter 3.2.4.3 --- Evaluation for the toxicity of DEHP and the intermediates/products by the Microtox® test --- p.40 / Chapter 4 --- Results --- p.42 / Chapter 4.1 --- Batch biosorption experiment --- p.42 / Chapter 4.1.1 --- Screening of biosorbents --- p.42 / Chapter 4.1.2 --- Optimization of biosorption conditions --- p.42 / Chapter 4.1.2.1 --- Effect of biosorbent concentration --- p.42 / Chapter 4.1.2.2 --- Effect of initial pH --- p.42 / Chapter 4.1.2.3 --- Effect of biosorption time --- p.46 / Chapter 4.1.2.4 --- Effect of temperature --- p.46 / Chapter 4.1.2.5 --- Effect of agitation rate --- p.46 / Chapter 4.1.2.6 --- Effect of initial DEHP concentration --- p.46 / Chapter 4.1.2.7 --- "Combinational effect of initial pH, chitin A concentration and initial DEHP concentration" --- p.51 / Chapter 4.1.2.8 --- Summary of biosorption conditions before and after optimization --- p.54 / Chapter 4.2 --- Extraction of adsorbed DEHP from chitin A --- p.54 / Chapter 4.2.1 --- Screening of extraction agents --- p.54 / Chapter 4.2.2 --- Determination of extraction time --- p.55 / Chapter 4.3 --- Batch PCO experiment --- p.56 / Chapter 4.3.1 --- Optimization of PCO conditions --- p.56 / Chapter 4.3.1.1 --- Effect of reaction time --- p.56 / Chapter 4.3.1.2 --- Effect of UV-A intensity --- p.57 / Chapter 4.3.1.3 --- Effect of TiO2 concentration --- p.59 / Chapter 4.3.1.4 --- Effect of H2O2 concentration --- p.60 / Chapter 4.3.1.5 --- Effect of initial pH --- p.61 / Chapter 4.3.1.6 --- Combinational effect of H2O2 concentration and initial pH --- p.62 / Chapter 4.3.1.7 --- Effect of CF --- p.63 / Chapter 4.3.1.8 --- Summary of PCO conditions before and after optimization --- p.63 / Chapter 4.3.2 --- Identification of intermediates/products of DEHP --- p.64 / Chapter 4.3.3 --- Evaluation for the toxicity of DEHP and the intermediates/products by the Microtox® test --- p.66 / Chapter 5 --- Discussion --- p.68 / Chapter 5.1 --- Batch biosorption experiment --- p.68 / Chapter 5.1.1 --- Screening of biosorbents --- p.68 / Chapter 5.1.2 --- Optimization of biosorption conditions --- p.69 / Chapter 5.1.2.1 --- Effect of biosorbent concentration --- p.69 / Chapter 5.1.2.2 --- Effect of initial pH --- p.69 / Chapter 5.1.2.3 --- Effect of biosorption time --- p.70 / Chapter 5.1.2.4 --- Effect of temperature --- p.71 / Chapter 5.1.2.5 --- Effect of agitation rate --- p.71 / Chapter 5.1.2.6 --- Effect of initial DEHP concentration --- p.71 / Chapter 5.1.2.7 --- "Combinational effect of initial pH, chitin A concentration and initial DEHP concentration" --- p.73 / Chapter 5.2 --- Extraction of adsorbed DEHP from chitin A --- p.74 / Chapter 5.2.1 --- Screening of extraction agents --- p.74 / Chapter 5.2.2. --- Determination of extraction time --- p.74 / Chapter 5.3 --- Batch PCO experiment --- p.74 / Chapter 5.3.1 --- Optimization of PCO conditions --- p.74 / Chapter 5.3.1.1 --- Effect of reaction time --- p.74 / Chapter 5.3.1.2 --- Effect of UV-A intensity --- p.74 / Chapter 5.3.1.3 --- Effect of TiO2 concentration --- p.75 / Chapter 5.3.1.4 --- Effect of H2O2 concentration --- p.75 / Chapter 5.3.1.5 --- Effect of initial pH --- p.76 / Chapter 5.3.1.6 --- Combinational effect of H2O2 concentration and initial pH --- p.77 / Chapter 5.3.1.7 --- Effect of CF --- p.77 / Chapter 5.3.2 --- Identification of intermediates/products of DEHP --- p.78 / Chapter 5.3.3 --- Evaluation for the toxicity of DEHP and the intermediates/products by the Microtox test --- p.79 / Chapter 6 --- Conclusions --- p.80 / Chapter 7 --- References --- p.83

In the past decade, single molecule imaging has advanced our understanding of processes at the molecular scale. Total internal reflection fluorescence (TIRF) microscopy is one implementation in particular that has been extensively applied in the study of protein adsorption to surfaces. The spatial and temporal resolution provided by TIRF has enabled dynamic measurements of individual proteins in solution, where previously only bulk measurements or static electron microscopy observations were possible. The ability to study individual proteins has revealed and sometimes clarified the complex interactions at their interfaces. Here, the utility of TIRF is expanded to introduce a new model of protein adsorption to the suface and to study the protein interface in contact with solution. Protein adsorption to surfaces has implications in surface biocompatibility, protein separation, and pharmaceutical nanoparticle development. For this reason, the phenomenon has been quantitatively by a variety of techniques, including single molecule imaging. The key data are the protein lifetimes on the surface, which have been shown to be broadly distributed and well-approximated by the sum of several exponential functions. The determined desorption rate constants are thought to reflect different interaction types between surface and protein, but the rates are not typically linked to a specific physical interaction. In the first part of this thesis, we establish appropriate imaging conditions and analysis methods for TIRF. A robust survival analysis technique is applied to capture the range of protein adsorption kinetics. In the second part, we utilize single molecule lifetime data from the adsorption of fibrinogen and bovine serum albumin (BSA) to glass surfaces and discover a heavy-tailed distribution: a very small fraction of proteins adsorbs effectively permanently, while the majority of proteins adsorb for a very short time. We then demonstrate that this characteristic power law behavior is well described by a model with a novel interpretation of the complex protein adsorption process. The second half of the thesis extends TIRF to study the solution-facing interface of the protein as opposed to the surface facing interface by establishing the parameters for a super-resolution imaging technique. Point accumulation for imaging nanoscale topography (PAINT) generates high-resolution images of the sample of interest through the positional tracking of many temporally-distinct instances of a fluorescent probe binding to the sample. Previously, this technique has been applied in the mapping of DNA nanostructures. Here, in the third part, we apply PAINT to the study of proteins. First, a workstream is established for a model system of Nile red and BSA. The kinetic parameters for the system are established to allow rational design of PAINT experiments with this system. The on-rate and off-rate for Nile red are determined. Additionally, the binding model between the two components is tested by studying how the presence of an inhibitor effects the parameters. In the final part, TIRF is used to study the protein-solution interface to examine the glycosylation of immunoglobulin A 1 (IgA1). Over 50% of eukaryotic proteins are glycosylated, and the glycan sequence is simultaneously difficult to study and crucial in the many functional roles proteins play. The glycosylation of IgA1, for example, plays a key role in the pathophysiology of IgA1 nephropathy. Lectins are proteins that bind to specifc glycan sequences and are often used to isolate glycosylated proteins. In this study, the appropriate surface conditions are established to allow specific binding between lectins and IgA1 glycans. The association and dissociation rate between lectins specific for the glycans on IgA1 are measured and affinity constants calculated. These efforts will help to rationally design experiments in the future to elucidate unknown glycan sequences on proteins.

Finally, the pharmacodynamic effects of propranolol powder formulation with different buffering were carried out in two healthy male subjects. The maximal reduction in heart rate was found at the saliva pH of 7.6, which corresponded to the pHmax of propranolol. A buffered propranolol sublingual tablet was then prepared to achieve the saliva pH around 7.6. The preliminary investigation confirmed that the sublingually administrated buffered propranolol tablet produced a faster and more pronounced heart rate reduction than the non-buffered commercial propranolol tablet. / Firstly, the use of the HO-1-u-1 cell culture for screening sublingual drug delivery was validated. The cells were seeded on cell culture inserts. The integrity of cell layers, inter-passage variation and directionality were assessed by measuring the resistance and the permeability of standard markers, beta-blockers and calcium channel blockers. The effect of pH, osmolarity and a permeation enhancer (GDC) were also studied. The results showed that HO-1-u-1 cells grown on inserts formed stratified and epithelial-like structure that preserved the typical histological feathers of the normal human sublingual epithelium. The maximal integrity was reached in 23 days. The Papp of beta-blockers and calcium channel blockers ranged from 2.89+/-0.17 x 10 -6 cm/s to 6.37+/-0.37 x 10-6 cm/s. The permeability of selected beta-blockers under different pH, osmolarity and GDC revealed that enhancing effects were significant for hydrophilic compounds but less for lipophilic compounds. / Secondly, fresh porcine sublingual mucosa was prepared and compared to the cell line model. Good correlations were obtained for both the Papp of beta-blockers and the enhancement ratios of pH and GDC between the two models. / The aims of the present study are (1) to develop and validate a human sublingual epithelial cell line model and (2) to demonstrate the application in sublingual development of cardiovascular drugs. / Thirdly, the steady-state flux (Jss) at various pH levels were measured. Results show that saturated propranolol solution at pH 7.0--7.6 resulted in a much higher Jss than the solution at other pHs. These data led to the development of theoretical equations for predicting the optimum pH (pHmax) for ionizable compounds. The calculation fitted well with the experimental data. / Wang Yanfeng. / Advisers: Moses S. S. Chow; Zhong Joan Zuo. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 184-). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Wong, Kin Shing Kinson. / Thesis submitted in: November 2007. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 145-158). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / 摘要 --- p.v / Contents --- p.viii / List of figures --- p.xv / List of plates --- p.xx / List of tables --- p.xxi / Abbreviations --- p.xxiii / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Heavy metals --- p.1 / Chapter 1.1.1 --- Characteristics of heavy metals --- p.1 / Chapter 1.1.2 --- Heavy metal pollution in Hong Kong --- p.2 / Chapter 1.1.3 --- Common usage of heavy metals --- p.4 / Chapter 1.1.3.1 --- Copper --- p.4 / Chapter 1.1.3.2 --- Nickel --- p.4 / Chapter 1.1.3.3 --- Zinc --- p.5 / Chapter 1.1.4 --- Toxicity of heavy metals --- p.5 / Chapter 1.1.4.1 --- Copper --- p.6 / Chapter 1.1.4.2 --- Nickel --- p.7 / Chapter 1.1.4.3 --- Zinc --- p.7 / Chapter 1.1.5 --- Treatment techniques for metal ions --- p.8 / Chapter 1.1.5.1 --- Chemical precipitation --- p.9 / Chapter 1.1.5.2 --- Ion exchange --- p.10 / Chapter 1.1.5.3 --- Activated carbon adsorption --- p.10 / Chapter 1.2 --- Biosorption --- p.11 / Chapter 1.2.1 --- Definition of biosorption --- p.11 / Chapter 1.2.2 --- Mechanism --- p.12 / Chapter 1.2.3 --- Advantages of biosorption --- p.13 / Chapter 1.2.4 --- Selection of biosorbents --- p.15 / Chapter 1.3 --- Chitinous materials --- p.17 / Chapter 1.3.1 --- Background of chitin --- p.17 / Chapter 1.3.2 --- Structures of chitinous materials --- p.18 / Chapter 1.3.3 --- Sources of chitinous materials --- p.18 / Chapter 1.3.4 --- Application of chitinous materials --- p.20 / Chapter 1.3.5 --- Mechanism of metal ion adsorption by chitin --- p.22 / Chapter 1.4 --- Activated carbon --- p.25 / Chapter 1.4.1 --- Characteristics of activated carbon --- p.25 / Chapter 1.4.2 --- Applications of activated carbon --- p.26 / Chapter 1.4.3 --- Factors affecting adsorption ability of activated carbon --- p.27 / Chapter 1.4.4 --- Advantages and Disadvantages --- p.28 / Chapter 1.4.4.1 --- Advantages (Adsorption) --- p.28 / Chapter 1.4.4.2 --- Advantages (Regerneration) --- p.28 / Chapter 1.4.4.3 --- Disadvantages (Adsorption) --- p.28 / Chapter 1.4.4.4 --- Disadvantages (Regeneration) --- p.29 / Chapter 1.5 --- Cation exchange resin --- p.29 / Chapter 1.5.1 --- Usages of cation exchange resin --- p.29 / Chapter 1.5.2 --- Characteristics of cation exchange resin --- p.30 / Chapter 1.5.3 --- Disadvantages of using cation exchange resin --- p.30 / Chapter 1.6 --- Magnetite --- p.31 / Chapter 1.6.1 --- Reasons of using magnetite --- p.31 / Chapter 1.6.2 --- Characteristics of magnetite --- p.31 / Chapter 1.6.3 --- Immobilization by magnetite --- p.32 / Chapter 1.6.4 --- Advantages of using magnetite --- p.33 / Chapter 1.7 --- The biosorption experiment --- p.33 / Chapter 1.7.1 --- The batch biosorption experiment --- p.33 / Chapter 1.7.2 --- The adsorption isotherms --- p.34 / Chapter 1.7.2.1 --- The Langmuir adsorption isotherm --- p.34 / Chapter 1.7.2.2 --- The Freundlich adsorption isotherm --- p.36 / Chapter 2. --- Objectives --- p.38 / Chapter 3. --- Materials and methods --- p.39 / Chapter 3.1 --- Adsorbents --- p.39 / Chapter 3.1.1 --- Chitin A --- p.39 / Chapter 3.1.2 --- Pretreatment of chitin A --- p.39 / Chapter 3.1.3 --- Magnetite --- p.39 / Chapter 3.1.4 --- Activated carbon --- p.41 / Chapter 3.1.5 --- Cation exchange resin --- p.41 / Chapter 3.1.6 --- Pretreatment of cation exchange resin --- p.41 / Chapter 3.2 --- Chemicals --- p.43 / Chapter 3.2.1 --- Metal ion solution --- p.43 / Chapter 3.2.2 --- Buffer solution --- p.43 / Chapter 3.2.3 --- Standard solution --- p.43 / Chapter 3.3 --- Immobilization of chitin A by magnetite --- p.44 / Chapter 3.3.1 --- Effect of chitin A to magnetite ratio --- p.44 / Chapter 3.3.2 --- Effect of amount of chitin A and magnetite in a fixed ratio --- p.45 / Chapter 3.3.3 --- Effect of pH --- p.45 / Chapter 3.3.4 --- Effect of immobilization time --- p.46 / Chapter 3.3.5 --- Effect of temperature --- p.46 / Chapter 3.3.6 --- Effect of agitation rate --- p.46 / Chapter 3.3.7 --- Effect of salinity --- p.46 / Chapter 3.3.8 --- Mass production of magnetite-immobilized chitin A --- p.47 / Chapter 3.4 --- Batch adsorption experiment --- p.47 / Chapter 3.5 --- "Optimization of physicochemical condition on Cu2+，Ni2+ and Zn2+ adsorption by MCA, AC and CER" --- p.48 / Chapter 3.5.1 --- Effect of equilibrium pH --- p.48 / Chapter 3.5.2 --- Effect of amount of adsorbent --- p.49 / Chapter 3.5.3 --- Effect of retention time --- p.49 / Chapter 3.5.4 --- Effect of agitation rate --- p.49 / Chapter 3.5.5 --- Effect of temperature --- p.50 / Chapter 3.5.6 --- Effect of initial metal ion concentration --- p.50 / Chapter 3.5.7 --- Adsorption isotherms --- p.50 / Chapter 3.5.8 --- Dimensionless separation factor --- p.52 / Chapter 3.5.9 --- Kinetic parameters of adsorption --- p.52 / Chapter 3.5.10 --- Thermodynamic parameters of adsorption --- p.53 / Chapter 3.6 --- "Recovery of Cu2+, Ni2+ and Zn2+ from metal ion-laden MCA" --- p.54 / Chapter 3.6.1 --- Performances of various solutions on metal ion recovery --- p.54 / Chapter 3.6.2 --- Multiple adsorption and desorption cycles of metal ions --- p.55 / Chapter 3.7 --- Statistical analysis of data --- p.55 / Chapter 4. --- Results --- p.56 / Chapter 4.1 --- Immobilization of chitin A by magnetite --- p.56 / Chapter 4.1.1 --- Effect of chitin A to magnetite ratio --- p.56 / Chapter 4.1.2 --- Effect of amount of chitin A and magnetite in a fixed ratio --- p.59 / Chapter 4.1.3 --- Effect of pH --- p.59 / Chapter 4.1.4 --- Effect of immobilization time --- p.59 / Chapter 4.1.5 --- Effect of temperature --- p.59 / Chapter 4.1.6 --- Effect of agitation rate --- p.64 / Chapter 4.1.7 --- Effect of salinity --- p.64 / Chapter 4.1.8 --- Mass production of magnetite-immobilized chitin A --- p.64 / Chapter 4.2 --- Batch adsorption experiment --- p.67 / Chapter 4.2.1 --- Screening of adsorbents --- p.67 / Chapter 4.3 --- "Optimization of physicochemical condition on Cu2+, Ni2+ and Zn2+ adsorption by MCA, AC and CER" --- p.70 / Chapter 4.3.1 --- Effect of equilibrium pH --- p.70 / Chapter 4.3.2 --- Effect of amount of adsorbent --- p.74 / Chapter 4.3.3 --- Effect of retention time --- p.78 / Chapter 4.3.4 --- Effect of agitation rate --- p.82 / Chapter 4.3.5 --- Effect of temperature --- p.82 / Chapter 4.3.6 --- Effect of initial metal ion concentration --- p.86 / Chapter 4.3.7 --- Summary of optimized conditions for three metal ions --- p.87 / Chapter 4.3.8 --- Cost analysis of metal ion removal by three adsorbents --- p.87 / Chapter 4.3.9 --- Performance of reference adsorbents (AC and CER) --- p.87 / Chapter 4.3.10 --- Adsorption isotherms --- p.99 / Chapter 4.3.11 --- Dimensionless separation factor --- p.103 / Chapter 4.3.12 --- Kinetic parameters of adsorption --- p.106 / Chapter 4.3.13 --- Thermodynamic parameters of adsorption --- p.113 / Chapter 4.4 --- "Recovery of Cu2+, Ni2+ and Zn2+ from metal ion-laden MCA" --- p.113 / Chapter 4.4.1 --- Performances of various solutions on metal ion recovery --- p.113 / Chapter 4.4.2 --- Multiple adsorption and desorption cycles of metal ions --- p.117 / Chapter 5. --- Discussions --- p.121 / Chapter 5.1 --- Immobilization of chitin A by magnetite --- p.121 / Chapter 5.1.1 --- Effect of chitin A to magnetite ratio --- p.121 / Chapter 5.1.2 --- Effect of amount of chitin A and magnetite in a fixed ratio --- p.121 / Chapter 5.1.3 --- Effect of pH --- p.122 / Chapter 5.1.4 --- Effect of immobilization time --- p.122 / Chapter 5.1.5 --- Effect of temperature --- p.122 / Chapter 5.1.6 --- Effect of agitation rate --- p.123 / Chapter 5.1.7 --- Effect of salinity --- p.123 / Chapter 5.2 --- Batch adsorption experiment --- p.123 / Chapter 5.2.1 --- Screening of adsorbents --- p.123 / Chapter 5.3 --- "Optimization of physicochemical condition on Cu2+, Ni2+ and Zn2+ adsorption by MCA, AC and CER" --- p.124 / Chapter 5.3.1 --- Effect of equilibrium pH --- p.125 / Chapter 5.3.2 --- Effect of amount of adsorbent --- p.126 / Chapter 5.3.3 --- Effect of retention time --- p.127 / Chapter 5.3.4 --- Effect of agitation rate --- p.128 / Chapter 5.3.5 --- Effect of temperature --- p.128 / Chapter 5.3.6 --- Effect of initial metal ion concentration --- p.129 / Chapter 5.3.7 --- Summary of optimized conditions for three metal ions --- p.130 / Chapter 5.3.8 --- Cost analysis of metal ion removal by three adsorbents --- p.132 / Chapter 5.3.9 --- Performance of reference adsorbents (AC and CER) --- p.133 / Chapter 5.3.10 --- Adsorption isotherms --- p.133 / Chapter 5.3.11 --- Dimensionless separation factor --- p.135 / Chapter 5.3.12 --- Kinetic parameters of adsorption --- p.136 / Chapter 5.3.13 --- Thermodynamic parameters of adsorption --- p.139 / Chapter 5.4 --- "Recovery of Cu2+, Ni2+ and Zn2+ from metal ion-laden MCA" --- p.140 / Chapter 5.4.1 --- Performances of various solutions on metal ion recovery --- p.140 / Chapter 5.4.2 --- Multiple adsorption and desorption cycles of metal ions --- p.141 / Chapter 6. --- Conclusions --- p.143 / Chapter 7. --- References --- p.145

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