Adsorption takes place whenever a solid surface is exposed to a gas or liquid, and is characterized by an increase in fluid density near the interface. Adsorbents have attracted attention in the ongoing effort to engineer materials that can effectively remove various pollutants from wastewaters. Carbon adsorbents are a logical choice as an adsorption material due to their low costs and large surface areas. The adsorption of chromium(VI), aluminium and copper onto commercial activated carbon was studied in a series of batch, kinetic and column experiments. The adsorption of the three ions was studied separately followed by studies of the competition between the ions in binary and ternary systems. The experimental data was utilized to set up models for sorption of chromium(VI), aluminium and copper onto commercial activated carbon. This was done to enhance the understanding of the governing processes controlling adsorption as well as to develop a tool to predict the fate of chromium(VI), aluminium and copper in a calcareous environment. To avoid the precipitation of the ions, the binary and ternary experiments were conducted without pH adjustment. This thesis has used multiple analytical techniques in order to enhance the knowledge of Cr(VI), AI(III) and Cu(II) binding to the activated carbon adsorbent and thus attempts to interpret.the potential binding mechanisms. The changes in adsorbent functional groups and surface topography after chromium binding were monitored using FT-IR and SEM/EDX analysis. The experimental studies include: i) evaluation and characterisation of the commercial activated carbon; ii) evaluation and optimisation of commercial activated carbon removal capability, kinetics and mechanisms toward Cr(VI), AI (III) and Cu(II) via the batch, kinetic and continuous adsorption systems. From the pH studies, it was observed that pH 2 produced the highest removal of chromium. The ternary solution at pH 2 showed less removal of chromium than the other solutions suggesting that the combined -effect of Cu and AI metals was more considerable. Two common adsorption isotherms, i.e. the Freundlich and Langmuir models As well as Redlich-Peterson model were employed to describe the adsorptive characteristics of the activated carbon. The adsorptive kinetic studies revealed that the adsorption of activated carbon followed the pseudo-second order kinetic models, indicating the adsorption mechanism was dependent on the adsorbate and adsorbent interaction.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:680505 |
| Date | January 2015 |
| Creators | Campalani, Charles Campbell |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
Page generated in 0.0017 seconds