Title

Preparation and surface chemistry of novel chitosan / bamboo charcoal / poly (methacrylate) composites for the adsorption of creatinine

Date of Award

2017

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Chemistry (Standard Program)

Department

Chemistry

First Advisor

Fabicon, Ronaldo M., Ph.D.

Abstract

A global concern is a shortage of kidney donors becomes a major impediment to the treatment of kidney disease, leaving millions of chronic kidney patients without total functional replacement. Chronic kidney disease reduces survival, quality of life and treatment is too expensive. Hence, this study came about to explore an alternative but renewable and low-cost materials to be used as an adsorbent in a kidney assist device.The use of biomass - derive materials such as bamboo plants for the production of activated charcoal become attractive nowadays due to its ease of access, renewability and low price. Bamboo charcoal has recently been considered by various research investigations due to its high adsorption potential to various target molecules, high surface area, microporous nature and amphoteric surface functional groups. The surface chemistry of bamboo charcoal and its composite with poly(methacrylate) (PMAA) bound with chitosan to form a novel material of Chitosan / Bamboo Charcoal / Polymethacrylate or CTS/BC/PMAA are presented in this paper. The following adsorbents were specifically studied: steam activated bamboo charcoal (BC), chitosan / bamboo charcoal (CTS/BC), chitosan / bamboo charcoal / poly(methacrylate), (CTS/BC/PMAA) composite beads. The surface characteristics of the adsorbents are elucidated using various surface characterization techniques. The adsorption potential for the capture of creatinine was studied using equilibrium and dynamic flow techniques. The initial biocompatibility of the composite beads were conducted using established procedures of Lactate Dehydrogenase (LDH) and [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] or MTT assays with L 929 fibroblast cells. Thermal studies such as Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA) have shown a successful coating of poly(methacrylate) and chitosan to the steam activated BC. The two composite beads such as Chitosan / Bamboo Charcoal (CTS/BC) and Chitosan / Bamboo Charcoal / Polymethacrylate (CTS/BC/PMAA) have shown an acidic surface as indicated by pH point of zero charge (pHpzc), Boehm titration, Fourier Transform - Infrared spectroscopy (FT-IR) and X-ray photoelectron Spectroscopy (XPS). The Brunnauer Emmett Teller (BET) and Scanning Electron Microscopy (SEM) revealed high surface area and microporous nature of the bamboo charcoal - containing composite beads such as Chitosan / Bamboo Charcoal (CTS/BC) and Chitosan / Bamboo Charcoal / Polymethacrylate (CTS/BC/PMAA). Results indicated that the composite beads adsorb the maximum amounts of creatinine at its isoelectric pH. Compared to the neat BC, however, there was observed a decrease in adsorption probably due to decrease in available micropores for adsorption. However, the presence of poly(methacrylate) in the composite rendered the material more accessible to polar substance with mechanical strength by preventing the release of carbon particles in the solution. The cell viability of Chitosan / Bamboo Charcoal (CTS/BC) and Chitosan / Bamboo Charcoal / Polymethacrylate (CTS/BC/PMAA) are 87.0% and 85.2%, respectively while the lactate dehydrogenase (LDH) assay revealed cytotoxicity of the beads between 34-42%.

Comments

The C4.P487 2017

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