Biomedical subjects

Yung-Chien Hsu

Publications and source records attributed to Yung-Chien Hsu.

7 recordsLinked to original sources

PubMed2006

Calcium enhanced COD removal for the ozonation of phenol solution.

In order to improve the chemical oxygen demand (COD) removal rate for the ozonation of phenol solution, ozonation combined with calcium binding was investigated. The results show that the addition of Ca(2+) can effectively enhance the COD removal rate. During the ozonation, calcium ion can bind with some of the intermediate products of phenol, including high molecular weight products, maleic acid and oxalic acid, to form insoluble precipitates. These calcium binding effects are responsible for the enhancement of COD removal. The variations of ADMI value during ozonation are similar for solutions with and without Ca(2+). However, the peak ADMI value in calcium-contained solution is lower than that without Ca(2+). As the phenol was completely decomposed, the ozone gas outlet concentration rapidly increases. The increasing rate of the ozone gas outlet concentration for ozonation with the presence of Ca(2+) is faster than that without Ca(2+). The optimal initial calcium dosage shows linear relationship with the initial phenol concentration, which is useful for practical application.

Calcium↗

PubMed2005

The effects of preozonation on the biodegradability of mixed phenolic solution using a new gas-inducing reactor.

In this study, the effects of preozonation on the biodegradability of mixed 2-chlorophenol/4-cresol solution were investigated using a new gas-inducing reactor, which can provide high ozone utilization efficiency. The decomposition rate of phenolic mixture, COD removal and TOC removal increases with increasing pH. A half-order overall kinetic model can correctly describe the decomposition of phenolic mixture. The BOD(5)/COD ratio of the preozonized solutions increases with increasing preozonation time, indicating that preozonation can enhance the biodegradability. Based on high ozone utilization rate, it is concluded that the best characteristic time can be chosen at the rapid increase of ozone gas outlet concentration. Since the ozone gas outlet concentration can be easily monitored, it is a useful real-time control parameter in preozonation.

Biodegradation, Environmental↗

PubMed2004

The enhancement of the biodegradability of phenolic solution using preozonation based on high ozone utilization.

In this research, the effects of preozonation on the biodegradability of 4-cresol, 4-nitrophenol and 2-chlorophenol solutions were investigated using a new gas-inducing reactor with high ozone utilization rate. The extent of preozonation may be monitored by determining the characteristic ozonation behaviors of preozonized phenolic solutions, such as residual phenolic concentration, ADMI value and ozone gas outlet concentration. Experimental results showed that as the initial phenolic compounds decomposed completely, the ozone gas outlet concentration rapidly increases. In addition, at pH 7, a peak ADMI value appears during the preozonation of 4-cresol and 2-chlorophenol, while for 4-nitrophenol the ADMI value decreases monotonically. Based on the characteristic ozonation behaviors and the ozone utilization rate, three characteristic times were chosen in order to have better control on the extent of preozonation. The effect of preozonation on the biodegradability of preozonized phenolic solution was studied based on these characteristic times. The intermediate products during the preozonation were also identified. The variation of BOD5 is strongly dependent on the accumulation of intermediate products. It is suggested that the best characteristic time is as the rapid increase of ozone gas outlet concentration in this study. The biodegradability (BOD5/COD) of preozonized 4-cresol, 2-chlorophenol and 4-nitrophenol solutions increase to 0.18, 0.26 and 0.33, respectively, for the best characteristic time.

Biodegradation, Environmental↗

PubMed2004

Decolorization of dye RB-19 solution in a continuous ozone process.

This work studied the decolorization of dye C.I. Reactive Blue 19 (RB-19) solution in a new gas-inducing reactor under continuous process. The decolorization behavior, decolorization kinetic, ozone utilization rate (UO3), and Chemical Oxygen Demand (COD) are examined under various operation conditions, such as input ADMI color values (ADMIo), input liquid flow rates (QL), input ozone gas concentrations (CO3,i), input gas flow rates (Qg), and agitation speeds (N). Experimental results of decolorization behavior indicate that the American Dye Manufactures Institute (ADMI) removal percentage (RADMI) decreases with increasing ADMI color value input rate or decreasing ozone input rate. For the study of ozone utilization rate, UO3 increases with increasing ADMI color value input rate or decreasing ozone input rate. The 70% ADMI removal percentage can be regarded as the index of the competition of dye and its unknown intermediates for ozone. In addition, the increase of the agitation speed can improve the ADMI removal percentage as well as the ozone utilization rate. A pseudo-first order kinetic model is adopted to describe the decolorization behavior. At steady state, the overall decolorization rate constant, kADMIs.s., can be expressed as a function of liquid flow rate, input ADMI color value, input ozone gas concentration, gas flow rate, and agitation speed. This correlation can be used to predict the ADMI color value at steady state (ADMIs.s.) and the reactor size in the continuous process. The deltaO3/deltaCOD is dependent on the liquid composition. The higher the dye concentration in the liquid, the higher the deltaO3/deltaCOD. The COD removal percentage (RCOD) and the ozone utilization rate can be further improved by using the continuous operation with two reactors in series.

Anthraquinones↗

PubMed2003

Application of gas-inducing reactor to obtain high oxygen dissolution in aeration process.

The application of gas-inducing reactor to obtain high oxygen dissolution has been investigated at various operation conditions including agitation speed, temperature (20-40 degrees C), pressure (1.0-1.2 atm) and working liquid levels. Correlations regarding onset speed, agitation power consumption, gas holdup and oxygen mass transfer coefficient were established from experimental data. Onset speed can be accurately predicted with modified Froude number. The agitation power consumptions before and after onset speed is a function of Froude number and working liquid level. Gas holdup is an important factor influencing the mass transfer of oxygen after onset speed. In the study of mass transfer of oxygen (T=20 degrees C, P=1 atm), the highest dissolved oxygen concentration is as high as 39.34-39.92 mg x L(-1). The value of k(L)a is within 0.511-1.792 min(-1). The k(L)a is not affected by the oxygen gas pressure (1.0-1.2 atm). However, k(L)a increases with increasing temperature. The gas-inducing reactor of this study has higher k(L)a than the other type of gas-inducing reactor under the same unit volume power consumption. The pure oxygen utilization rate of this system can be as high as 100%.

Air Movements↗

PubMed2003

The effectiveness of a new gas-induced reactor in treating phenolic wastewater by ozonation and hydrogen peroxide.

A new Gas-Induced Reactor (GIR) has been developed to improve the efficiency of ozone utilization in water treatment. In this study, the GIR was used to investigate the behavior of ozonation of aqueous phenol solution by means of O3 and O3/H2O2 processes in order to explore the feasibility and efficiency of treating such wastewater using the new GIR. The study observed the decomposition of phenol, utilization of ozone, and variation of TOC during ozonation, varying pH values, phenol initial concentrations, ozone input concentrations, and hydrogen peroxide dosages. The study concluded that the new GIR was capable of performing effective and efficient ozonation of phenolic wastewater, maintaining high ozone utilization ratios at all experimental pH values and initial phenol and ozone concentrations. The optimal pH condition for phenol removal was around 11. The best molar ratios of initial hydrogen peroxide over input ozone among the performed experiments were about 20 at pH 7 and 10 at pH 9 and 11. The primary operational energy used for treating a tonne of wastewater was 66 MJ, giving treatment costs of about USS1.0 per tonne.

Gases↗

PubMed2003

Peroxone process for RO-16 and RB-19 dye solutions treatment.

To obtain a better treatment efficiency for dye or textile wastewater, a semi-batch and a continuous peroxone process using a new gas-inducing reactor were investigated in this study. In the semi-batch peroxone process, the results show that the peroxone process does not improve the color value (ADMI) removal rate, regardless of the pH value. However, the chemical oxygen demand (COD) removal rate could be enhanced in this peroxone process at higher pH value, but the extent of improvement is only slight. The optimal molar ratio of hydrogen peroxide to ozone (H2O2/O3) is 1.0, and at this condition, the mass ratio of removed COD to consumed ozone (deltaCOD/deltaO3) is twice as high as that in the ozone alone process. In the continuous peroxone process, the hydrogen peroxide addition also does not improve the ADMI removal. However, the COD removal is improved more significantly in the continuous peroxone process. The optimal H2O2/O3 molar ratio for the continuous peroxone process varies with the input liquid flow rate (QL). For liquid flow rate of 0.5 L/min, the optimal H2O2/O3 molar ratio is 3.0 and the COD removal percentage (R(COD)) reaches 50.0 to approximately 55.8%, providing about 15 min oxidation time, for the two kinds of dye solutions that were investigated in this study. The optimal residual hydrogen peroxide concentration in the working solution ([H2O2]res.) is about 1.7 x 10(-2) mol/L, providing an input rate of ozone at 8.8 x 10(-2) mol/h.

Anthraquinones↗