• Journal of Korean Society of Water and Wastewater
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• v.25 no.1
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• pp.15-21
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• 2011

Arsenic is one of the most abundant contaminant found in waste mine tailings, because of it's carcinogenic property, the countries like United states of America and Europe have made stringent regulations which govern the concentration of arsenic in drinking water. The current study focuses on different treatment methods for removal of arsenic from waste water. Treatment method the high strength arsenic waste water is treated with Fe(III)-ettringite by co-precipitation method. Number of experiments were carried out to decide the optimal dosage of Fe(III)-ettringite to treat arsenic waste water. The Fe(III)-ettringite was synthesized by taking appropriate equivalent ratios of calcium oxide and ferric chloride in proportion to the arsenic. The best removal efficiencies of 94% were observed at a As/(Ca: Fe) ratio of 1:3. The maximum removal of arsenic was observed in pH range of 12. But as the pH increases the arsenic removal efficiency decreases as portlandite is formed in the pH above 12. The analysis of surface of precipitate conform the needle like structure of ettringite. This treatment technique has promising features such as, the chemicals required in the treatment as well as the sludge generated can be reduced. The operating pH range is in alkaline region which is advantageous over traditional treatment process which has lower pH. Also the co-precipitation not only helps in removal of arsenic but also heavy metals.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11b
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• pp.159-163
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• 1999

Model experiments were conducted to investigate the effect of different fillers on the removal of toner ink. Combinations of different papers (commercial photocopy paper and filler-free paper), fillers (calcium carbonate, kaolin clay, and talc), and chemicals(1-octadecanol, stearic acid, oleic acid, and TOFA) and stearic acid were found to be effective in detachment and agglomeration of toner ink. Furthermore, pH had little effect on toner detachment and agglomeration, indicating both protonated fatty acids and their anions are equally effective. In the presence of either kaolin clay or talc, all these agglomerating agents are equally effective, although a slightly higher dosage(1% for clay and 2% for talc as compared with control) is required, presumably due to the adsorption of chemical by the filler. Calcium carbonate filler, on the other hand, has a significant and adverse effect on the fatty acids used but has little effect on 1-octadecanol with the exception of possible adsorption. While stearic acid is not effective, a much higher level of oleic acid or TOFA is needed when calcium carbonate fillers are present as compared to the filler-free case. Fatty acids react with calcium carbonate to form calcium salts. The availability of fatty acid anion for toner detachment and agglomeration is determined by the solubility of calcium salt of a given fatty acid. Calcium oleate is 10 times more soluble in water than calcium stearate.

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.701-708
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• 2008

As a countermeasure for reduction of corrosion in the delivery and distribution pipes used for tap water, materials for the pipelines in-houses and the effect of water quality on corrosivity of water pipelines were investigated in the distribution system of Han river. As the corrosion index at 6 water purification facilities of Han river, average Langelier Saturation Index (LI) of raw and finished water were -1.0 and -1.4 respectively and average Larson Index (LR) were 9.5 and 9.9, respectively. And also corrosion potential showed corrosivity in finished water (-431~-462 mV) as well as raw water (-426~-447 mV). This results indicate that tap water quality of han river have corrosivity. To understand the corrosivity effect in pipe material used for premise distribution system, water quality of stagnant tap water and tap water were analyzed and the differences between them were calculated. The difference concentration of iron, copper and zinc were $12.9{\mu}g/L$, $31.0{\mu}g/L$ and $45.0{\mu}g/L$ respectively in galvanized steel pipe for use more than 15 years and showed highest concentration. As a result, the control to corrosivity in the water pipelines, corrosivity control treatment in the water purification system can be applied. In advance it is necessary to monitor corrosivity of water quality using corrosive index because corrosivity may differ from the seasonal and regional characteristics and water chemicals dosage. For the future the guideline for corrosion index have to be established.

• Advances in environmental research
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• v.10 no.1
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• pp.59-86
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• 2021

Landfilling is the most commonly adopted method for a large quantity of waste disposal. But, the main concern related to landfills is the generation of leachate. The leachate is high strength wastewater that is usually characterized by the presence of high molecular recalcitrant organics. Several conventional methods are adopted for leachate treatment. However, these methods are only suitable for young leachate, having high biodegradability and low toxicity levels. The mature and stabilized leachate needs advanced technologies for its effective treatment. Advanced oxidation processes (AOPs) are very suitable for such complex wastewater treatment as reported in the literature. After going through the literature survey, it can be concluded that Fenton-based approaches are effective for the treatment of various high/low strength wastewaters treatment. The applications of the Fenton-based approaches are widely adopted and well recognized due to their simplicity, cost-effectiveness, and reliability for the reduction of high chemical oxygen demand (COD) as reported in several studies. Besides, the process is relatively economical due to fewer chemical, non-sophisticated instruments, and low energy requirements. In this review, the conventional and advanced Fenton's approaches are explained with their detailed reaction mechanisms and applications for landfill leachate treatment. The effect of influencing factors like pH, the dosage of chemicals, nature of reaction matrix, and reagent ratio on the treatment efficiencies are also emphasized. Furthermore, the discussion regarding the reduction of chemical oxygen demand (COD) and color, increase in biodegradability, removal of humic acids from leachate, combined processes, and the pre/post-treatment options are highlighted. The scope of future studies is summarized to attain sustainable solutions for restrictions associated with these methods for effective leachate treatment.

• Journal of Pharmaceutical Investigation
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• v.32 no.4
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• pp.277-284
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• 2002

Lansoprazole, pharmaceutics for acid-related diseases, is unstable in low pH environments and generally coated with enteric polymer to obtain gastroresistance in stomach. Because its storage stability is influenced by acidic substitutes of enteric polymer, alkaline chemicals wεre generally addεd to dosage form as a stabilizer. In this experience, we coated lansoprazole bead with sodium alginate and evaluated the effect of bead size and sodium alginate coating on the storage stability and dissolution profile of lansoprazole. Sodium alginate solution containing lansoprazole was sprayed as a droplet into 3% (w/v) $CaCl_2$ solution and the resultant bead was coated with starch, sodium alginate, and hydroxypropyl methylcellulose phthalate. The content of lansoprazole granule not coated with sodium alginate decreased to 57.96% of initial content when stored at a severe condition for 4 weeks, but that of lansoprazole granule coated with sodium alginate before enteric coating decreased little and as the thickness of sodium alginate film increased, the content of bead didn't decreased for 4 weeks. Sodium alginate film also improved the gastroresistance without much influencing the maximum dissolution rate.

• Journal of Pharmaceutical Investigation
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• v.40 no.2
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• pp.85-90
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• 2010

Docetaxel-loaded liposomes were prepared by emulsion-solvent evaporation method, then coated with chitosan at room temperature and lyophilized. This system was designed in order to improve solubility and stability of docetaxel in the GI tract for oral drug delivery. The solubilizing effect of some frequently used solubilizers and/or liposome was determined. Among the results docetaxel-loaded liposomes prepared with 0.5% TPGS as a solubilizer showed 100-fold higher solubility than docetaxel. In a stability test, mean particle size of different liposome formulations was measured by a particle size analyzer in simulated gastric fluid (SGF) and in simulated intestinal fluid (SIF). The particle size of uncoated liposomes was significantly increased compared with that of chitosan-coated liposomes in SGF, however, there was no significant difference between coated and uncoated liposome in SIF. It is evident that chitosan-coated liposomes were more stable in GI conditions. The release characteristics of docetaxel-loaded liposomes were also investigated in three buffer solutions (pH 1.2, 4.0, 6.8). Docetaxel release did not occur in pH 1.2 for 4 hrs. However, in pH 4.0 and 6.8 conditions, docetaxel was gradually released over 24 hrs as a sustained release. It seems that aggregation and precipitation of particles by electrostatic interaction might protect docetaxel from being released. In Conclusion, the results from this study show that the chitosan-coated liposomes may be useful in enhancing solubility and GI stability of docetaxel.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.231-237
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• 2006

Grease barrier food containers are commonly used for packaging of fast food, cooked food, and food in general. Greaseproofing is also used for certificate paper and label paper etc. Different pulp raw materials, due to their different fiber morphology and chemical compositions, produce papers of varying characteristics. We used optical photomicroscopy and fiber analysis data to evaluate fiber morphology and traits under various beating conditions in order to understand which pulp raw materials produced superior greaseproofing property when a fluorinated greaseproofing agent was added internally. The experiment studied 9 species of pulps, including 2 softwood (northern pine and radiata pine) bleached kraft pulps which were beaten to 550 and 350 mL CSF, respectively; 3 hardwoods (eucalypts, acacia, mixed Indonesian hardwoods) bleached kraft pulps which were beaten to 450 and 250 mL CSF, respectively; and nonwood fibers of reed, bagasse, and abaca. A fluorinated greaseproofing chemical at 0.12% dosage with respect to dry pulp was added to each pulp preparation and formed handsheets. A total of 67 sets of handsheets were prepared, and their basis weights, thickness, bulks, opacities, wet opacities, air resistance, water absorption and degrees of greaseproofing were measured for an overall evaluation of pulp and freeness on greaseproofing papers. The experimental fiber length, coarseness and distribution characteristics and the greaseproofing results suggest that softwood pulps (radiate pine > northern pine) were superior to hardwood pulps (eucalypts > acacia > mixed Indonesian hardwoods). The unbeaten pulps gave papers with high porosities and nearly devoid of greaseproofing property. Greaseproofing is proportional to air resistance. Among the nonwood fibers, bagasse had the best greaseproofing property, followed by reed and abaca was the poorest. With regards to waterproofing property, hardwood pulps (mixed Indonesian hardwoods > acacia > eucalypts) were better than softwood pulps (northern pine > radiate pine). Among the Nonwood fibers, reed had the highest waterproofing property, and it was followed by abaca, while bagasse had the poorest waterproofing characteristic. In summary, bleached kraft northern pine, eucalypts and reed pulps were best suited for making greaseproofing papers, Freeness of the pulps should be kept at $200{\sim}280mL$ CSF for optimal performance.

• Journal of Embryo Transfer
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• v.28 no.2
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• pp.157-162
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• 2013

Methoxychlor (MXC) was developed to be a replacement for the banned pesticide DDT. HPTE [2,2-bis (p-hydroxyphenyl)-1,1,1-trichloroethane], which is an in vivo metabolite of MXC, has strong oestrogenic and anti-androgenic effects. MXC and HPTE are thought to produce potentially adverse effects by acting through oestrogen and androgen receptors. Of the two, HPTE binds to sex-steroid receptors with greater affinity, and it inhibits testosterone biosynthesis in Leydig cells by inhibiting cholesterol side-chain cleavage enzyme activity and cholesterol utilisation. In a previous study, MXC was shown to induce Leydig cell apoptosis by decreasing testosterone concentrations. I focused on the effects of MXC on male mice that resulted from interactions with sex-steroid hormone receptors. Sex-steroid hormones affect other organs including the kidney and liver. Accordingly, I hypothesised that MXC can act through sex-steroid receptors to produce adverse effects on the testis, kidney and liver, and I designed our experiments to confirm the different effects of MXC exposure on the male reproductive system, kidney and liver. In these experiments, I used pre-pubescent ICR mice; the puberty period in ICR mice is from postnatal day (PND) 45 to PND60. I treated the experimental group with 0, 100, 200, 400 mg MXC/kg b.w. delivered by an intra-peritoneal injection with sesame oil used as vehicle for 4 weeks. At the end of the experiment, the mice were sacrificed under anaesthesia. The testes and accessory reproductive organs were collected, weighed and prepared for histological investigation. I performed a chemiluminescence immune assay to observe the serum levels of testosterone, LH and FSH. Blood biochemical determination was also performed to check for other effects. There were no significant differences in our histological observations or relative organ weights. Serum testosterone levels were decreased in a dose-dependent manner; a greater dose resulted in the production of less testosterone. Compared to the control group, testosterone concentrations differed in the 200 and 400 mg/kg dosage groups. In conclusion, I observed markedly negative effects of MXC exposure on testosterone concentrations in pre-pubescent male mice. From our biochemical determinations, I observed some changes that indicate renal and hepatic failure. Together, these data suggest that MXC produces adverse effects on the reproductive system, kidney and liver.

• The Korean Journal of Pesticide Science
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• v.2 no.1
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• pp.85-90
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• 1998

A series of experiments were carried out to determine the effect of seed dressing application of chemicals on the early occurring rice insect pests. The number of small brown planthopper adults per 3hills in seed-dressing plot of Imidacloprid WS (Im WS) was 1.6 and its control efficacy was over 90%, compared with that of untreated plot. Rice water weevil was observed in the density of 8.8 larvae per 5 hills seed-dressed Im WS plots(showing 95.5% of control efficacy). Control efficacy of Im WS and Im GR against adult weevils lasted for 26 days after treatment and was higher than that of Carbofuran GR. Rates of injured stems by rice stem maggot and injured leaves by rice leaf miner were 3% and 3.7% in Im WS treatment plot respectively. Seed germination rate after seed dressing with recommended dosage (3 g/seed kg) of Im WS was 71 % on the 1st day and increased on 5th day up to that of untreated seed. The residual amount of Im in seed dressing plot was 0.11 ppm in rice roots and 0.05 ppm in leaves on the 40th day after treatment. Residual effect of Im WSI sustained for 50 days with over 95% insecticidal effect for the rice water weevil and over 90% for the brown planthopper. Quantity of the chemical applied in the field was calculated as 0.084 kg a.i./ha in seed dressing and 0.3 kg a.i./ha in seed box treatment, respectively It took 1 hour to treat insecticide by seed dressing, 2.5 hours by seed box applying, and 3.6 hours by water surface releasing per 990 $m^2$.

• Korean Journal of Ecology and Environment
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• v.40 no.3
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• pp.379-386
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• 2007

Nonylphenol (NP) has been well known as a major substance of surfactant and/or estrogenic environmental hormone. We tested toxic effects of nonylphenol on the population growth and development of aquatic organism such as algae (Microcystis aeruginosa), heterotrophic nanoflagellate (Diphylleia rotans), micro- (Brachionus calyciflorus) and macro-zooplankton (Daphnia magna) among eutrophic water food-web constituents. Dosage of NP treatment were 4 to 5 grades, according to each organism's tolerance based on pre-experiments; algae (0.01, 0.05, 0.10, 1.00 mg $L^{-1}$) Diphylleia rotans (0.5, 1,2. 5,6, 10 ${\mu}g\;L^{-1})$, Brachionus calyciflorus (0.1, 0.5, 1, 2.5, 5 ${\mu}g\;L^{-1}$), and Daphnia magna (0.5, 1, 5, 10, 50 ${\mu}g\;L^{-1}$), respectively. Toxic effects were measured by the changes of biomass of each organism after NP treatment. All experiments were triplication. As suggested, the higher concentration of NP treatment, the stronger inhibited the population growth of all organisms tested. In view of toxicity, a variety of concentration of NP showed a significant growth inhibition to organism; algae to 0.05 $mg\;L^{-1}$, D. rotans and B. calyciflorus to 1.0 ${\mu}g\;L^{-1}$, and D. magna to 5.0 ${\mu}g\;L^{-1}$, respectively. The $EC_{50}$ of each organism to the nonylphenol are as follows; 3. calyciflorus (2.49 ${\mu}g\;L^{-1}$), D. rotans (3.49 ${\mu}g\;L^{-1}$), D. magna (7.61 ${\mu}g\;L^{-1})$, and M. aeruginosa (47 ${\mu}g\;L^{-1})$. NP toxic effects on the development of zooplankton like egg production showed some differences in treatment concentration between Brachionus calyciflorus ${0.1{\sim}1NP{\mu}g\;L^{-1})$ and Daphnia magna $(0.5{\sim}5NP\;{\mu}g\;L^{-1})$. These results suggest that a strong growth inhibition of predator or grazer by the nonylphenol can stimulate the algal growth, or can play important role in evoking the nuisance algal bloom in eutrophic water with enough nutrients.