Browsing by Author "HUANG, CP"

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ADSORPTION CHARACTERISTICS OF CU(II) ON HUMUS-KAOLIN COMPLEXES
(1995-11-01)
HUANG, CP
;
YANG, YL
;
交大名義發表
;
環境工程研究所
;
National Chiao Tung University
The sorption of Cu(II) was investigated on synthetic humus-kaolin complexes. Two groups of humic fractions were compared to investigate the effect of molar mass on the Cu(II) adsorption capacity. Another approach was to compare the capacities of humic acid (HA) and fulvic acid (FA) to adsorb Cu(II). The adsorption capacity of fulvic acid on kaolin is smaller than that of humic acid. The adsorption behavior of fulvic acid on kaolin can be described by a Langmuir-type isotherm. However, the adsorption isotherm of humic acid on kaolin exhibits non-langmuir behavior. The results showed the affinity of Cu(II) on humic acid was greater than by fulvic acid. However, the affinity of Cu(II) adsorption by humic acid with large molar mass was equal to that by humic acid with small molar mass. A modified model incorporating a proton competition coefficient can differentiate the competitive effect from Cu(II) adsorption. A constant (K-m) independent of pH was derived from this model. HA-Kaolin complex has a greater Cu(II) affinity constant that FA-Kaolin complex according to models with either a single-site or a continuous distribution.
FACTORS AFFECTING THE PHOTOCATALYTIC DEGRADATION OF DICHLORVOS OVER TITANIUM-DIOXIDE SUPPORTED ON GLASS
(1993-12-01)
LU, MC
;
ROAM, GD
;
CHEN, JN
;
HUANG, CP
;
環境工程研究所
The photocatalytic degradation of organophosphorus insecticide, dichlorvos, on glass-supported titanium dioxide was investigated. The photoreactor coated with titanium dioxide was illuminated with a 20 W black-light W fluorescent tube. The aqueous solution containing dichlorvos was continuously pumped through the photoreactor. Several factors, such as the initial dichlorvos concentration, dissolved oxygen, electrolytes, flow rate and temperature, affecting the oxidation rate of dichlorvos were studied. The results indicate that photocatalysis can be an effective process for the degradation of dichlorvos. The activated energy for the photocatalytic degradation of dichlorvos is 28.4 kJ mol(-1). The initial quantum yield for the destruction of dichlorvos is 2.67%. Increasing the flow rate and initial dichlorvos concentration increases the dichlorvos degradation rate. Total mineralization requires a much longer illumination time than the disappearance of dichlorvos. Phosphate-containing intermediates are more stable than chloride-containing intermediates. It is shown that the photocatalytic oxidation of dichlorvos follows the Langmuir-Hinshelwood-type behavior, and reaction byproducts display an inhibiting effect on degradation rate.
ION-EXCHANGE BETWEEN MONOVALENT CATIONS AND FUNGAL MYCELIA ACCOMPANYING COPPER(II) ADSORPTION
(1992-04-05)
HUANG, CP
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環境工程研究所
;
Institute of Environmental Engineering
MICROTOX BIOASSAY OF PHOTODEGRADATION PRODUCTS FROM PHOTOCATALYTIC OXIDATION OF PESTICIDES
(1993-11-01)
LU, MC
;
ROAM, GD
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CHEN, JN
;
HUANG, CP
;
環境工程研究所
The mineralization of toxicants and the reduction of toxicity were investigated via the photocatalytic reaction. Dichlorvos (an insecticide), 2,4-D (a herbicide) and propoxur (an insecticide) were used as the model compounds in these experiments. Total organic carbon analyzer was used as a measure of mineralization of toxic compounds to assess the efficiency of photocatalytic mineralization. Microtox bioassay was employed in evaluating the toxicity of solutions treated by photocatalysis. The rate of photocatalytic mineralization is more efficient in acidic than in alkaline solution. The degradation pathway and toxicity of pesticides treated in photocatalytic process are pH dependent. Ultraviolet absorption spectra were also used for showing the different characteristics of the compounds undergoing photocatalytic mineralization.
PHOTOCATALYTIC OXIDATION OF DICHLORVOS IN THE PRESENCE OF HYDROGEN-PEROXIDE AND FERROUS ION
(1994)
LU, MC
;
ROAM, GD
;
CHEN, JN
;
HUANG, CP
;
環境工程研究所
The photocatalytic oxidation of dichlorvos has been investigated with two different reactors. The reactor using 254 nm light is a system with TiO2 suspensions. The 360 nm light is used as the light source of the fixed system which was TiO2 coated on the inner surface of the reactor. In terms of quantum yield, the 254 nm radiation is more effective for dichlorvos oxidation than the 360 nm light. The effect of H2O2 on dichlorvos oxidation shows a negative performance. The influence of H2O2 on the photocatalytic oxidation of dichlorvos is greater in the fixed system than that in the suspension system. The ferrous ions can induce the photo-Fenton-type reaction. However, the photocatalytic oxidation of dichlorvos will be inhibited slightly at the concentration of 1.0 x 10(-5) M Fe+2. This result is explained in terms of the net production of hydroxyl radical.
REMOVAL OF TRACE CD(II) FROM AQUEOUS-SOLUTIONS BY FUNGAL ADSORBENTS - AN EVALUATION OF SELF-IMMOBILIZATION OF RHIZOPUS-ORYZAE
(1994)
HUANG, CP
;
CHIU, HH
;
交大名義發表
;
環境工程研究所
;
National Chiao Tung University
Rhizopus oryzae are grown in the fermenter as discrete and nearly spherical pellets. The pellets' size and structure suggest that more agitation produces smaller and more compact pellets. In this study, the agitation intensity in the fermenter is changed to produce the suspension mycelium and pelletized mycelia with various sizes. Acid-washing and heat treatments are applied to deactivate the fungi. Experimental results indicate that acid-treated mycelia are preferential to either fresh or heat-treated pelletized mycelium for use in the binding of Cd(II) ions. Based on engineering and economic considerations, this study screens an optimum size of pellet to be 3.8 mm which is formed under 2-day pre-cultivation and 5-day harvest in a fermenter at 300 rpm of agitation.