Titanium dioxide mediated photocatalytic degradation of polyvinyl alcohol (PVA) was studied in an annular photoreactor with two 6W (Emax=365nm) UV lamps as light source. In the presence of both TiO2 and light, and initial concentration of 30mg/l, 55.3% of PVA was found to degrade after an hour. The effects of initial concentration, pH and the addition of H2O2 on the rate of degradation of PVA were studied. The results showed that it was more effective for PVA to be degraded under acidic or alkaline condition. The order of reaction rates was pH10>pH9>pH4>pH5> pH7. Proper amount of H2O2 could improve the photodegradation rate of PVA. However, the further increase of H2O2 might inhibit the system efficiency. Fourier transformed infrared spectroscopy (FTIR) indicated that several carbon-carbon bonds were scissored, which led to the formation of short-chain compounds during the photocatalytic oxidation of PVA. These intermediates were also degraded with prolonged reaction.

Tissue concentrations of some mineral elements appeared to be influenced by plant Fe status. The influence of Fe deficiency on Cu uptake and accumulation in Commelina communis, and the relationship between Cu uptake and root Fe (Ⅲ) chelate reductase (FCR) activity were investigated in this study. The results showed that Cu accumulation in C. communis was increased with the drop of Fe concentration in nutrient solution. Cu uptake in C. communis was significantly enhanced by Fe deficiency. Cu uptake in Fe-deficient plants were still higher than that of Fe-sufficient plants when P-type ATPase inhibitor Na3VO4 was added in the solution, which demonstrated that Fe deficiency induced stimulation of the plasma membrane H+-ATPase did not play a role in the enhanced Cu uptake. Fe and Cu deficiency could induced root Fe (Ⅲ) chelate reductase activity in C. communis. Both Fe (Ⅲ) chelate reductase activity aud Cu concentration in roots inhibited distinctly by cycloheximide, a kind of protein synthesis inhibitor. In the time course of Fe deficiency, there simultaneously appeared Cu concentration and FCR activity peaks in roots at day 9. All above evidences demonstrated Cu uptake aud accumulation in C. communis were probably related to the root FCR activity.

To gain information on organic pollutants in wateresediment systems, a compartment model was applied to study the sorption course of phenanthrene and pentachlorophenol (PCP) in sediments. The model described the time-dependent interaction of phenanthrene and PCP with operationally defined reversible and irreversible (or slowly reversible) sediment fractions. The interactions between these fractions were described using first order differential equations. By fitting the models to the experimental data, apparent rate constants were obtained using numerical optimization software. The model optimizations showed that the amount of reversible phase increased rapidly in the first 10d with the sorption time, then decreased after 10d, while the amount of irreversible phase increased in the total sorption course. That suggested the mass transport between reversible phase and irreversible phase. The extraction efficiency with hot methanol ranged from 36% to 103% for phenanthrene and from 65% to 101% for PCP, with the trend of decreasing with sorption time.

This study focused on the appropriate catalyst preparation and operating conditions for maximizing catalytic reduction efficiencyof nitrate into nitrogen gas from groundwater. Batch experiments were conducted with prepared Pd and/or Cu catalysts with hydrogen gas supplied under specific operating conditions. It has been found that Pd-Cu combined catalysts prepared at a mass ratio of 4:1 can maximize the nitrate reduction into nitrogen gas. With an increase in the quantityof the catalysts, oth nitrite intermediates and ammonia can be kept at a low level. It has also been found that the catalytic activity is mainly affected by the mass ratio of hydrogen gas to nitrate nitrogen, and hydrogen gas gauge pressure. Appropriate operating values of H2/NO3-N ratio, hydrogen gas gauge pressure, pH, and initial nitrate concentration have been determined to be 44.6g H2/g N, 0.15atm, 5.2(-), 100mgL-1 for maximizing the catalytic reduction of nitrate from groundwater.

A novel tri-primer polymerase chain reaction method (TP-PCR) was developed for the construction of a fused fpg gene, in which no endonuclease and ligase were used. Instead, two templates and three specifically designed primers were applied. Results showed that pheB and gfp genes, which encodes the catechol 2, 3-dioxygenase and the green fluorescent protein (GFP), respectively, were successfully fused into an fpg gene through the rapid TP-PCR system, indicating that TP-PCR method could be a useful tool for DNA fragment fusion in which no proper endonuclease sites were available.