• Analytical Science and Technology
• /
• v.14 no.6
• /
• pp.510-515
• /
• 2001

There has been an increasing need for analytical methods of dissolved total iron (tFe) that are highly sensitive, rapid, inexpensive and simple for environmental samples. A sensitive flow injection analysis (FIA) method for determining the concentration of tFe in environmental samples was developed. The proposed method required 10 minutes and only $500{\mu}L$ of sample for and analysis. The standard deviation was 5.0% at $0.5{\mu}gL^{-1}$ (n=6), and the detection limit was $0.075{\mu}gL^{-1}$. The developed method was applied to environmental samples such as tap water, mineral water, rain, snow and cloud water. Since this FIA system was free form interferences of coexisting ions commonly found in samples, sub-${\mu}gL^{-1}$ level of tFe could be easily determined without further preconcentration and separation.

• Analytical Science and Technology
• /
• v.16 no.6
• /
• pp.466-474
• /
• 2003

This paper describes the concentrations of total dissolved iron (tFe) and $Fe^{2+}$ in rainwater and snow, the relationship of Fe species with other metals and ions in bulk rainwater, and the $Fe^{2+}$ generation mechanism in aqueous samples in rainwater of time series collection. Volume weight mean concentrations of tFe and $Fe^{2+}$ were 3.22 and $1.25{\mu}gL^{-1}$ in bulk rainwater, and 50.1 and $43.5{\mu}gL^{-1}$ in snow, respectively. $Fe^{2+}$ was significant fraction to the tFe, accounted for 3.25-93.4% of the tFe in rainwater and 87% in snow. We also investigated temporal variations of tFe, $Fe^{2+}$, other metals and ions in rainwater of time series collection during rain event. Although the concentration range of tFe was different from those of other species, a decreasing trend of tFe from the beginning of the rain event was similar with other species. However, though $Fe^{2+}$ did not show such a decreasing trend, $Fe^{2+}$/tFe was in good correlation with solar radiation. From the results of multiple linear regression analysis and thermodynamic calculations (Mineql+), $Fe^{2+}$ in our samples may be generated from photochemical reduction of $Fe^{3+}$ species (such as $Fe(OH)^{2+}$,$Fe(OH)^{2+}$ and Fe-oxalate) at daytime.

• Membrane and Water Treatment
• /
• v.14 no.1
• /
• pp.27-33
• /
• 2023

In previous studies, solely ferric (Fe³⁺) and calcium (Ca²⁺) ions were commonly used for removal of PO₄-P (considered as T-P in this study) in wastewater via chemical precipitation. Herein, the removal of total phosphorus (T-P) in wastewater was performed using various mineral and lime dissolved solutions. The dissolution kinetics of different minerals (feldspar, olivine, elvan, illite, sericite, and zeolite) and lime was compared and used their solutions for T-P removal of real wastewater. The highest T-P removal (almost 90%) was obtained by the lime dissolved solution and followed by zeolite, illite, feldspar, and others. We observed a significant co-relationship (R of 0.96) between the amount of initial Ca²⁺ and T-P removal. This was induced by formation of hydroxyapatite-like mineral via Ca-P precipitation reaction at high pH solution. Furthermore, additional removal of suspended solid (SS) and chemical oxygen demand (COD) was achieved by only lime dissolved solution. Finally, the lime-feldspar dissolved solutions were prepared at different ratios (10-50%), which showed a successive T-P removal up to two times by samples of 40 and 50%.

• Journal of the Korean GEO-environmental Society
• /
• v.11 no.8
• /
• pp.33-40
• /
• 2010

In this study, evaluation of basic unit of non-point pollutant, which is fundamental evaluation of non-point loading, was conducted using both road point and angle of intersection point in Maesong area, West coast highway by utilizing Event Mean Concentrations(EMC). Concentration of pollutants except heavy metals at these two points rapidly decreased in 30 minutes after start of runoff. According to the results of EMC, for both sampling points, it was determined that the concentrations of TSS(Total Suspended Solid), $BOD_5$(Biological Oxygen Demand), and DOC(Dissolved Organic Carbon) were higher than those of wastewater effluent standard in Korea, however, the concentrations of T-N(Total Nitrogen) and T-P(Total Phosphorus) were lower than those of the standard. In terms of heavy metals, Fe, Pb, and Zn showed higher concentrations than others. When compared with the units established by the Ministry of Environment in Korea, the basic units of $BOD_5$ and T-N in this study were lower. On the other hand, when compared with foreign units, Cu, Pb, and Zn showed approximately 10 times higher concentrations. It was estimated that a long term monitoring should be conducted for obtaining additional data and more reliable basic units for the non-point pollutnats based on the results from this study.

• Journal of Environmental Science International
• /
• v.28 no.5
• /
• pp.511-520
• /
• 2019

This study was investigated to improve the phosphorus release and water quality by transformation of sedimentary P fraction for application of $CaO_2$. For the experiment, 0.5% (w/w) of $CaO_2$ was homogenized in the sediment and incubated with the control for 20 days. The analytical results showed that pH increased with $CaO_2$ and redox potential (ORP) was improved in the sediment of the reactor. The growth rate of chlorophyll-a was lower in the $CaO_2$ reactor and Dissolved Oxygen (DO) of overlying water maintained higher than that of the control. Total phosphorus (T-P) concentration in the overlying water increased from the initial concentration to 0.304mg/L in the control at 20 days. The reactor of $CaO_2$ was lowered by 29.3%. Ex-P, Fe-P and Ca-P in sediment P fraction were increased with the $CaO_2$. The formation of bound Fe-P and Ca-P in the sediments seemed to control the release of P by removing the Soluble Reactive Phosphorus (SRP) presented in the pore water. From the result, this indicated that the reduction of P release from the sediments seems to be effective in suppressing the eutrophication of P and improving the oxygen condition in the water quality with the application of $CaO_2$.