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About this book

This book reviews some of the latest developments in the field of water treatment using multi-functional chitosan-based materials. It covers the production of chitosan beads and membranes from chitosan powder, as well as modification techniques for enhancing the material for commercial and industrial purposes. The book summarizes the results of experimental adsorption/desorption studies for elucidating the underlying reaction mechanism of heavy-metal removal from wastewater, presenting an advanced overview of an array of characterization techniques such as Fourier-transform infrared spectroscopy, thermogravimetric analysis, x-ray diffraction, and scanning electron microscopy. Additionally, it features a look at the development and application of specialized engineering software and image analysis for modelling the kinetics of adsorption. This book is ideal for scientists and engineers working in the broader field of environmental materials science. It is all well suited for chemists, as well as industrial and civil engineers, interested in wastewater treatment and mitigation of water pollution

Table of Contents

Frontmatter

Chapter 1. A Comprehensive Approach to Heavy Metal Removal by Adsorption: A Review

Abstract
In the years, the existence and accumulation of heavy metal in water has become a general problem. Owing to the fact that these heavy metals tend to pose health hazard to human and aquatic live if their concentration exceeds the maximum contaminant level. This study seeks to review the use of chitin- and chitosan-based material in comparison with some other adsorptive materials such as activated carbon, zeolite and peat that have been used in the past for heavy metal ion removal. Their merits and shortcomings in application are also discussed. The maximum adsorption capacities obtained by these adsorbents from Langmuir isotherm model and the conditions such as temperature, equilibrium time, initial concentration range and pH at which these adsorption capacities were obtained are presented. The characteristics of physical and chemical adsorption and factors affecting adsorption of metal ions were presented and discussed. Consequently, the desorption of these ions from metal-loaded adsorbent is also highlighted, as they provide important information of the re-use of the adsorbent.
Ephraim Igberase, Peter Ogbemudia Osifo, Tumisang Seodigeng, Ikenna Emeji

Chapter 2. Thermodynamics, Kinetics and Desorption Studies of Heavy Metal Ions by Grafted Cross-Linked Chitosan Beads Composites

Abstract
Functionalized grafted cross-linked chitosan bead (G/CR-CS), prepared from pure chitosan for the removal of scavenging metal ions from aqueous solutions, has been studied. The modified material was then characterized using FTIR, SEM, TGA, BET and XRD to assert successful modification. Parameters such as effect of contact time, pH and temperature were investigated to determine their physicochemical properties for the maximum removal of metal ions using batch applications. The results indicated that adsorption performance of the modified chitosan beads can be modelled efficiently using Langmuir isotherm and pseudo-second-order kinetic. Also, calculated thermodynamic parameters (ΔG0, ΔH0 and ΔS0) indicated that the adsorption of metal ions onto the grafted cross-linked chitosan is spontaneous and endothermic in nature.
Ephraim Igberase, Peter Ogbemudia Osifo, Tumisang Seodigeng, Ikenna Emeji

Chapter 3. Adsorption of Pb(II), Cu(II), Ni(II), Zn(II), Cr(VI) and Cd(II) Ions by Microwave-Improved Grafting Technique of Cross-Linking Composite Chitosan Beads. Studies Concerning Equilibrium, Isotherm and Desorption

Abstract
Due to the flexibility of chitosan, chemical improvement of chitosan has become progressively important, allowing the material to be easily changed in a way that enhances its characteristics in binding processes. Chitosan solution was cross-linked with glutaraldehyde in this study, and the cross-linked solution was used in the manufacture of the beads and then grafted with ethylene acrylic acid afterwards. Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were used to obtain the chemical properties of the beads. Binding of Pb(II), Cu(II), Ni(II), Zn(II), Cr(II) and Cd(II) ions from aqueous solution by grafted cross-linking chitosan beads (GXXB) was examined in relation to pH, temperature, initial concentration, contact time, agitation speed and ionic strength. The results found from binding investigation were applied in isotherm, thermodynamic and kinetic report. The model such as Langmuir, Temkin and Dubinin–kaganer–Radushkevich (DKR) was effective in explaining the isotherm data for the binding of adsorbate onto adsorbent, while the model Freundlich was not productive in explaining the experimental data. Pseudo-second-order and intraparticle model were accurate in explaining kinetic data. Thermodynamic parameters including Gibb free energy shift (Go), enthalpy change (Ho) and entropy change (So) were measured and the marks reported a spontaneous and endothermic binding of Pb(II), Cu(II), Ni(II), Zn(II), Cr(II) and Cd(II) ions on GXXB. For the adsorbate examined, the regeneration of the spent GXXB was successful.
Ephraim Igberase, Peter Ogbemudia Osifo, Tumisang Seodigeng, Ikenna Emeji

Chapter 4. Investigation into the Adsorption of Cadmium and Lead by Polyaniline Grafted Cross-Linked Chitosan Beads from Aqueous Solution

Abstract
This research explored the enhancement of chitosan beads by cross-linking and grafting to use the grafted beads to extract cadmium and lead from polluted water. XRD and SEM characterized the beads to bear evidence of positive cross-linking and grafting. Batch investigation was conducted with regards to the parameters of adsorption such as pH, initial concentration, contact time and adsorbent dose. Equilibrium data were collected from the adsorption investigation, and the data were compared with the isotherm models including Langmuir and Freundlich. The maximum adsorption potential for cadmium and lead ions was found to be, respectively, 145 mg/g and 114 mg/g at a temperature of 45 °C from the Langmuir model. Thermodynamic parameters such as Gibbs free energy change (ΔGo), enthalpy change (ΔHo) and entropy shift (ΔSo) were subsequently determined and the findings illustrate that polyaniline adsorption of cadmium and lead ions on the produced adsorbent (GXCS) is spontaneous and endothermic in nature. The first-order pseudo- and second-order pseudo-models have been used for the study of kinetic data for both metal ions. The data match well with the second-order pseudo-model. Over five consecutive cycles of adsorption/desorption, the GXCS filled with cadmium and lead ions was measured. Nevertheless, 0.5 M HCl was successfully used among the eluents examined in desorbing the adsorbent expended and among the eluents that was investigated 0.5 M HCl was successfully used in desorbing the spent adsorbent and a percentage desorption of 98.94 and 97.50% was acquired for cadmium and lead ions correspondingly, at a desorption time of 180 min.
Ephraim Igberase, Peter Ogbemudia Osifo, Tumisang Seodigeng, Ikenna Emeji

Chapter 5. Biopolymer Chitosan Membranes Prepared from Fishery Waste for the Removal of Zinc Ions from Aqueous Systems by Adsorption

Abstract
Chitosan was derived from the Cape rock crab outer shell, as seen in the areas of Cape Town, South Africa, and was exploited in the manufacture chitosan particles employed in the development of porous polymer chitosan membranes through a step reversal procedure. The chitosan membrane was cross-linked with 2.5% glutaraldehyde; chitosan membrane (CS) and cross-linked chitosan membrane (XCS) were characterize by FTIR, XRD, SEM-EDX and TGA. Equilibrium findings showed that the Langmuir equilibrium model can be appropriately applied in explaining zinc adsorption on XCS and the maximum adsorption potential for temperatures between 303 and 313 K was 2.64 mmol g−1. The adsorption operation was discovered to be endothermic, with 20 kJ mol−1 adsorption enthalpy. Flux via XCS is a mechanical mechanism with a decline in the adsorption rate (1.91–1.30 mmol g−1) as the flux rises (2–55 L m−2 hr−1). XCS adsorption of metal ions has also been noticed to be impacted by co-ions, where the influence of nitrates has been considered to restrict adsorption, whereas sulphates have been proven to raise adsorption. The regeneration of the adsorbed zinc ions was accomplished employing sulphuric acid and hydrochloric acid solutions as eluants. The former was considered to be a more powerful eluant. As a result, a sulphuric acid solution with a pH of 2 can retrieve up to 90% of the adsorbed zinc. Consequently, upon recovery, the adsorption capacity was observed to be lowered. Upon regeneration, this decline in adsorption efficiency may be due to membrane mass loss of approximately 11%. The functional stability of the membrane was compromised following two regeneration periods, and the membranes were no longer functional.
Ephraim Igberase, Peter Ogbemudia Osifo, Tumisang Seodigeng, Ikenna Emeji

Chapter 6. Modelling of Packed Bed Column for the Adsorption of Cu(II) Ions Using Chemically Enhanced Chitosan Beads

Abstract
In this study, the removal of Cu(II) from aqueous solution using modified Chitosan as a chelating adsorbent was examined in a packed bed column. The characterization of the modified Chitosan using SEM analysis reveals orderly porous structure while BET analysis indicates that the material possesses large surface areas. Using swan model to fit the adsorption experimental data, the column breakthrough curves for the adsorption of Cu(II) ions onto the adsorbent was reasonably predicted well. The model predicted that at pH of 5.1, the diffusion coefficient was calculated to be between 2.82 × 10−10 and 3.12 × 10−10 m2/s at different bed heights. Following several adsorption and desorption cycles carried out, 5.0 and 11.0% mass loss of the beads was observed during the third and fourth cycles of adsorption and desorption cycles. The maximum adsorption capacities of the absorbent in the second, third and fourth cycles of adsorption were calculated to be 98, 91 and 86%, respectively. However, the adsorption performances of the absorbent was reduced greatly, as 22% weight loss was observed in the mass of the beads during the fifth cycle of adsorption desorption operations.
Ephraim Igberase, Peter Ogbemudia Osifo, Tumisang Seodigeng, Ikenna Emeji

Chapter 7. Use of Diethylenetriamine Grafted onto Glyoxal Cross-Linked Chitosan Beads for Efficient Batch System Adsorption

Abstract
This study examined the removal of synthesized wastewater ions Cu(II), Pb(II), Cd(II), Zn(II), Ni(II) and Cr(VI) using modified chitosan material. Chitosan beads (CS) were produced and interlinked with glyoxal solution. Cross-linking was observed to intensify the mechanical intensity and chemical firmness of the beads in acid mixture and also to intensify the crystallinity of the beads in the process, which is a drawback, as the beads tend to have decreased rate of removal of adsorbate. The cross-linked chitosan beads (DCS) were grafted with diethylenetriamine to reduce this drawback. Before tests of adsorption, the beads were characterized. The amine concentration of the grafted cross-linked beads (GDCS) was observed to be almost equal to the binding capability (qmax); this suggests that the chitosan amine group is the most reactive group. The qmax was found to be 6.3 mmol/g with a grafting degree of 44.2%. However, with the Swan model, where the experimental and simulated data were in near agreement, the kinetics of the adsorption process was represented relatively well. The effective diffusion coefficients (Deff) found by applying the model to the data from the experimental were observed to be in the range of 2.25 × 10−10 and 2.50 × 10−10 for adsorption to GDCS by Cu(II), Pb(II), Cd(II), Zn(II), Ni(II) and Cr(VI).
Ephraim Igberase, Peter Ogbemudia Osifo, Tumisang Seodigeng, Ikenna Emeji

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