TAN, Thiam Chye

Professorial Fellow

PhD (Chem. Eng.) UMIST, 1971
BE (Hons) (Met. Eng.) Otago, 1964

Contact information
Blk E5, 4 Engineering Drive 4, #03-18, Singapore 117576
Tel: (65) 6516 2192   Fax: (65) 6779 1936
Email: chetantc@nus.edu.sg

RESEARCH

Effect of Dissolved Solutes on Phase Equilibria

Close-boiling and azeotropic solvent mixtures are often separated by adding an extraneous component to alter their phase equilibria as in extractive, azeotropic and salt distillation processes. Screening of the solute for the salt distillation involves experimental determination of the phase equilibria of the solute-solvents mixture and hence is costly and time-consuming. Two theoretical models describing the phase equilibria of multicomponent solvent-solute systems were developed and experimentally verified (Tan T. C., Chem. Eng. Res. & Des. 65(1987): 355-366;68(1990):93-103). The solute effect is predicted based on the boiling points of the solvent components having the same solute concentration as the mixture. This provides a rapid and cheap method of screening solutes for the salt distillation. This study is extended to include liquid-liquid equilibria and gas solubility.

Biosensors for Monitoring Environmentally and Medically Important Chemical Solutes

Biosensors, which combine a bioactive element with a sensing device, are increasingly used in process control and analytical instruments. We have successfully developed techniques to fabricate stable biosensors with long life span, for example the mixed Bacillus sensor for sensing biochemical oxygen demand in wastewaters, tissue powder dopamine sensors, oxalate and benzene microbial sensors. A high temperature process for killing microbial cells with little or no effect on the viability/activity of the enzyme system in the cells was developed recently. Biosensors using such thermally-killed cells show BOD and dopamine sensing characteristics comparable to those given by the living cells. Theoretical models to describe the transient and steady-state single and multicomponent (BOD) sensing behaviour were developed and experimentally verified. Research on thermally killed cells is extended to include complex microbial culture.

Solid-State High Temperature Chemical Sensors for Environmentally/Industrially Important Gases

Gas sensing is important to environmental and industrial process control programmes. High temperature gas sensors based on yttria-stabilized zirconia oxygen sensor coupled with a suitable oxide catalyst were designed and fabricated for sensing hydrogen, carbon monoxide and hydrocarbons in air. Theoretical models describing the sensing mechanism and process were developed and experimentally verified for each of these gases. Research is continuing on simultaneous sensing of various gases in a multicomponent mixture.

SELECTED PUBLICATIONS

T. C. Tan and C. H. Wu, "BOD Sensors Using Multi-species Living or Thermally Killed Celss of a BOD Microbial Culture", Sensors and Actuators B, 54, 252 (1999).

Z. R. Qian and T. C. Tan, "A model for Multicomponent Biosensing and its Application to a Dead Cell Based BOD Biosensor", Chemical Engineering Science, 58, 3281 (1998).

Y. Chen and T. C. Tan, "Modelling and Experimental Study of the Transient Behaviour of Plant Tissue Sensors in Sensing Dopamine", Chemical Engineering Science, 51, 1027 (1996).

Y. Tan and T. C. Tan, "Modelling and Sensing Characteristics of an Amperometric Hydrocarbon Sensor," Chemical Engineering Science, 51, 4001 (1996).

T. C. Tan and B. H. Ng, "Effect of Mixed Dissolved Solutes on the Vapour-liquid Equilibrium of Ethanol-water System: Prediction and Experimental Verification", Chemical Engineering Research and Design. Transactions of the Institution of Chemical Engineers: Part A.,71, 53 (1993).