Biomedical subjects

Jyh-Herng Chen

Publications and source records attributed to Jyh-Herng Chen.

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↗

PubMed2005

Separation of gallium and arsenic in wafer grinding extraction solution using a supported liquid membrane that contains PC88A as a carrier.

Wafer grinding extraction solution was passed through a supported liquid membrane (SLM) that contained PC88A (2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester) as a carrier, to separate gallium from arsenic by selective permeation. The SLM separation process was conducted under various conditions. The kind of membrane supporter, the pH of the feed, the feed concentration, and the HCl content in the strip governed the concentration of gallium and arsenic in the strip phase. The conditions determined as optimal in the laboratory test were used to perform the pilot test. Well separation between gallium and arsenic was performed in both laboratory and pilot tests. Hydrophobic membrane polytetrafluoroethylene (PTFE) with 0.2 microm pores was the best of three membrane supporters. The most efficient separation was obtained using an acidic feed (pH at 1.8) with 1000 ppm gallium. Over a 12-h period of stripping, the striped Ga concentration increased with the HCl concentration from 0.5 to 2.0 M and then leveled off. The recovery rate in the pilot test exceeded that on the laboratory scale because the membrane area was greater. The pilot test yielded a high recovery percentage of gallium (at 91%) and a low recovery of arsenic (merely 1.3 ppm) in the strip over 72 h.

Arsenic↗

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

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↗