Philosophiae Doctor - PhD / This thesis firstly reports on the development and characterization of reagent-less and cobalt(III) sepulchrate[Co(Sep)³⁺] mediated biosensor platforms (biosensor platform 1 and biosensor platform 2), with human recombinant heme thiolate, cytochrome P450 3A4 isoenzyme (CYP3A4), as biorecognition component. Secondly, each biosensor platform was evaluated by using an entirely different category of compound as model substrate, with the overall objective being the development of alternative analytical method for the detection and quantification of each of these substrates,by amperometric transduction method. In this regard biosensor platform 1 was evaluated for the detection of 2,4-dichlorophenol, whereas biosensor platform 2 was evaluated for the detection of protease inhibitor (PI) HAART drug, indinavir. Fourthly, this dissertation also reports on the use of genetic engineering as complimentary method during biosensor investigations, as source for continuous supply of catalytically active biological recognition component. With respect to the preparation of the biosensors in particular, biosensor platform 1 was constructed by entrapping the commercially sourced full-length, wild type CYP3A4 on a pre-formed electroactive carrier matrix, consisting of Co(Sep)³⁺–modified nafion membrane on a glassy carbon electrode. In this regard, the nafion-Co(Sep)³⁺ composite was prepared by integrating the Co(Sep)³⁺ species into a pre-formed nafion film through manual drop-coating and mixing methods.

The objectives of this research were to obtain the optimum operating conditions for a catalytic wet air process and to investigate their reaction kinetics. Either the ferrouscyanide (Fe(CN)64¡Ð) or the 2,4-dichlorophenol (2,4-DCP) solution was treated by the catalytic wet air oxidation (CWAO) process using three metal ions (Cu2+, Ce3+, and Mn2+) as catalysts or with the Mn/Ce composite oxide catalysts, respectively. In addition, the biodegradability of the effluent derived from the CWAO (2,4-DCP) process was studied. Results show that the effect of addition of the Cu2+ ion on the wet air oxidation (WAO) of Fe(CN)64¡Ð solution is significant because the Cu2+ ion plays in a role of catalyst, which may lower the activation energy (Ea) during the first-stage of the CWAO process. However, either the Ce3+ or Mn2+ ion did an adverse effect on the Fe(CN)64¡Ð removal, even they had a worse removal than that did by the WAO run without any catalyst addition. The Ea value of the first-stage in the WAO of the Fe(CN)64¡Ð solution process was calculated to be 40.5 KJ mol¡Ð1. On the other hand, the Ea values of the CWAO process with an addition of the Cu2+, Ce3+, or Mn2+ ion, were reduced to 14.1, 16.0, and 20.4 KJ mol¡Ð1, respectively. Obviously, the values of Ea can be reduced to promote the pollutants removal by an addition of suitable catalysts into the WAO process. It was observed that 2,4-DCP is difficult to be decomposed in the thermal pyrolysis process, but the conversion of 2,4-DCP is significant in the WAO process. With an application of the Mn/Ce composite oxide catalyst in the CWAO process to treat the 2,4-DCP solutions resulted in a better removal than that did by the WAO process. The higher the reaction temperature was applied, the higher 2,4-DCP removal was obtained. Also, the catalyst in a higher Mn/Ce molar ratio would increase the removal of 2,4-DCP during the CWAO runs, while the catalyst in a Mn/Ce molar of 7:3 showed the best 2,4-DCP removal of 96.5%. It is suggested that the reaction temperature of the CWAO process could be controlled 40 K lower than that required in the WAO run to reach an equivalent 2,4-DCP removal efficiency. The Ea value of the WAO of 2,4-DCP process performed in a semi-batch type reactor were 13.6 and 23.7 KJ mol¡Ð1, respectively, for the first-stage and the second-stage reactions. However, the Ea values of the both reaction stages in the CWAO of 2,4-DCP run were reduced to 9.1 and 5.7 KJ mol¡Ð1, respectively. If the CWAO of 2,4-DCP was performed in an up-flowing fixed -bed reactor, a second-order formula was found. Also, the activation energy and the frequency constant of the CWAO of 2,4-DCP run were calculated to be 11.9 KJ mol¡Ð1 and 0.96 sec¡Ð1. In the Microtox® toxicity tests, the TUa,15 values of the effluent from the CWAO run were below 8.26, when the CWAO process was operated at 433 K and at a space velocity of less than 11.0 hr¡Ð1, and the Mn/Ce (7:3) composite oxide as a catalyst. On the other hand, the toxicity of the 2,4-DCP could be reduced greatly by being treated in the CWAO process over the Mn/Ce (7:3) composite oxide catalyst. It is possible to treat the 2,4-DCP solution in a concentration less than 500 mg L¡Ð1 to meet the discharging regulation standards using a CWAO run, and followed by an activated sludge unit in which the retention time of the wastewater could be sorter than twelve hours.

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The 2,4-Dichlorophenol (2,4-DCP) solution (400 mg L¡Ð1) was treated by a wet air oxidation (WAO) process at temperatures of 393¡Ð453 K under a total pressure of 3.0 MPa using either Mn /£^-Al2O3 or Mn-Ce /£^-Al2O3 composite oxide as a catalyst. A COD reduction was found only 19.2% within 60 min if the WAO process was performed in a semi-batch type reactor without any catalyst addition; however, a higher COD removal of 69.4% or 71.4% was achieved when the Mn /£^-Al2O3 or Mn-Ce /£^-Al2O3 oxide was applied in the WAO process, respectively. A catalytic wet air oxidation (CWAO) of 2,4-DCP solution using the Mn-Ce /£^-Al2O3 oxide as a catalyst was conducted in another up-flowing fixed-bed reactor at 433 K under a pressure of 3.0 MPa in a space velocity of 4.0 hr¡Ð1. The COD reduction of the solution of 2,4-DCP was found above 61.4%. Also, both BOD5 and COD values in the effluent from the CWAO process was examined, and the BOD5/COD ratio was about 0.64. On the other hand, it is possible to treat the 2,4-DCP solution (¡Õ400 mg L¡Ð1) to meet the discharging regulation standard (COD¡Õ100 mg L¡Ð1) began in 1998 at Taiwan using a CWAO run and followed by an activated sludge treatment unit. The Ea values of the CWAO of 2,4-DCP using the Mn /£^-Al2O3 oxide as a catalyst were 20.77 KJ mol¡Ð1 and 23.99 KJ mol¡Ð1, respectively, for the first-stage and the second-stage reaction, respectively. In addition, the Ea values of the CWAO of 2,4-DCP over the Mn-Ce /£^-Al2O3 oxide were 14.77 KJ mol¡Ð1 and 23.30 KJ mol¡Ð1, respectively, for the first-stage and the second-stage reaction. Obviously, the Mn-Ce /£^-Al2O3 oxide does a better job in reducing the activation energy of the CWAO of 2,4-DCP than the Mn /£^-Al2O3 oxide does. Unfortunately, 2,4-DCP is hardly decomposed to become a low molecule weight carbon acids by the WAO run undergoing at 493 K without any catalyst addition. Several intermediates, such as 2-chlorophenol, phenol, catechol, oxalic acid, and formic acid, of the effluent from the CWAO of 2,4-DCP run over the Mn-Ce /£^-Al2O3 oxide were determined with a high-performance liquid chromatography.

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