• Clean Technology
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• v.16 no.3
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• pp.162-171
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• 2010

The objective of this study is to develop cleaning agents for the indoor water supply pipe which is environmentally friendly and suitable for removing scale by using various organic acids, inorganic acids, and some additives. Among various organic acids, oxalic acid, citric acid, and malic acid showed good cleaning efficiency of iron oxides which were main components of the indoor water supply pipe scale. Several cleaning agents were formulated by adding chemical additives into these organic acids and evaluated for removal of iron oxides. In this study, it was found that nonionic surfactants were excellent for the removal of iron oxide scale among various additives. Two types of cleaning agents($F_1$, $F_2$) with comparatively high solvent power for iron oxides were formulated in this study. The cleaning agents $F_1$ made by organic acids and some additives were formulated to be safe and environmentally friendly, but seemed to have disadvantage due to their comparatively low cleaning efficiency of iron oxide than $F_2$. But, the cleaning agents $F_2$ prepared by adding inorganic acid a little to $F_1$ showed comparatively good cleaning efficiency of iron oxide and could be recommended for removing hard scale of iron oxides in the indoor water supply pipe. Thus, it is considered that the formulated cleaning agents should be selected based on the extent of scale in the indoor water supply pipe.

• Economic and Environmental Geology
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• v.48 no.6
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• pp.491-500
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• 2015

Batch experiments were performed to determine the feasibility of the surfactant-enhanced soil washing process at various washing conditions for the Kuwait soil seriously contaminated with the crude oil. The soil was sampled at a dried oil pond in Kuwait and its average TPH concentration was 223,754 mg/kg, which was too high to apply the conventional remediation process. Nine commercialized non-ionic surfactants were used for the batch experiment to measure the surfactant solubility for the crude oil because it was reported that they have worked for the soil remediation. Among them, three surfactants having high crude oil solubility were used for the soil washing experiment. From the result of batch experiment, 5% TritonX-100 washing solution showed the highest TPH removal efficiency (67%) for the crude oil contaminated soil. However, because the residual TPH concentration in the washed soil was still higher than the clean-up level in Kuwait (10,000 mg/kg), the repeated soil washing was performed. After five washings with 2% surfactant solution, the cumulative TPH removal efficiency was higher than 96% and the residual TPH concentration in the soil went down below the clean-up level. To measure the desorption capacity of TritonX-100 remained in the soil after the soil washing, the silica beads and the soil were washed five times with 2% TritonX-100 surfactant solution and then they were washed again with distilled water to detach the surfactant adsorbed on beads or soil. After five washings with surfactant solution, 7.8% and 19.6% of the surfactant was adsorbed on beads and soil, respectively. When additionally washed with distilled water, most of the residual surfactant were detached from beads and only 4.3% of surfactant was remained in soil. From the results, it was investigated that the surfactant-enhanced soil washing process with TritonX-100, Tergitol S-15-7, and Tergitol S-15-9 has a great capability for the remediation of the Kuwait soil seriously contaminated by crude oil (more than 220,000 mg/kg).

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1277-1284
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• 2005

Alkylphenol Polyethoxylate(APEs) and their metabolites were determined in the aquatic environment in the central Nakdong river basin. The concentrations of APE's ranged between $0.62{\sim}11.70\;{\mu}g/L$ from the Nakdong and the Kumho rivers, and were $70.00{\sim}212.50\;{\mu}g/L$ in the samples from the 3rd industrial complex stream and the Dalseo stream, which are both heavily polluted by industrial wastewater and domestic wastewater. The APEs revealed a removal rate of more than 87% by biodegradation and adsorption etc. in the wastewater treatment plant. Nonylphenol polyethoxylates(NPnEO) and Nonylphenol carboxylic acid(NPnEC) consisted of APE metabolites shifted from NP($n=4{\sim}10$)EO and NP($n=4{\sim}10$)EC to NP($n=1{\sim}3$)EO and NP($n=1{\sim}3$)EC or removed by the adsorption of activated sludge during the biological wastewater treatment process. Upper streams have a higher distributed rate of NP($n=7{\sim}10$)EO than water downstream. Continuous monitoring is necessary for non-point sources as well as point sources, such as a wastewater treatment plant. Effluent concentrations of nonylphenol(NP) in industrial wastewater and domestic wastewater averaged about 4.33 and $1.70\;{\mu}g/L$, respectively. In addition, the removal rate average was 90% in the wastewater treatment plant. NP concentrations in the rivers did not exceed $1.0\;{\mu}g/L$, which are prescribed by environmental risk concentration in the USA and Europe. However, NP required continuous monitoring, which detected over $0.1\;{\mu}g/L$ in all river areas.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.2
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• pp.147-157
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• 2023

Centella asiatica extract is widely used as a raw material for cosmetics due to its various effects, but it is difficult to expect penetration into the skin due to its high molecular weight and low solubility. In order to solve these problems, lipid-based liposomes of various types were developed to increase skin absorption. Therefore, in this study, we tried to increase the skin absorption rate by preparing transfersomes using surfactants as edge activators in existing liposomes. Liposome and transfersomes containing Span 80 and Tween 20, 60, 80, and 85, respectively, were prepared using a high-pressure homogenizer, and we evaluated the particle size, polydispersity index, zeta potential, and skin absorption rate. As a result, there was almost no change in the physical properties of particle size, polydispersity index and zeta potential from 25 ℃ to 60 d, and the particle size of transfersomes containing Tween 20, 60, and 80 increased after 60 d at 45 ℃. Madecassoside, main substances of the Centella asiatica extract was used as an standard and madecassoside was measured and calculated when measuring the skin absorption rate using Franz diffusion cells. As a result, formulations containing Tween 20 were the most, whereas formulations containing Span 80 were the least. According to the skin absorption coefficient (Kp) value, all formulations showed 'very fast', and the absorption rate was similar or greater than that of liposomes, except for formulations containing Span 80. Through this, it was confirmed that the larger the HLB value of the nonionic surfactant, the smaller the particle size of the transfersome, and the increased skin absorption rate due to the increased flexibility of the vesicle membrane. Through this study, transfersome using surfactant as an edge activator can be expected to solve local skin problems not only as a cosmetic raw material or product, but also by increasing skin absorption.