• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.47-50
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• 2009

Nutrient losses, especially nitrogen and phosphorus, in agricultural runoff can contaminate surface and ground water, leading to eutrophication. Thus, erosion control is crucial to minimizing nutrient losses from agricultural land. Assessments of various erosion control practices were carried out under various cropping system, soil management practices, and slope conditions by means of a lysimeter study and under artificial rainfall. Soil and nutrient losses were monitored in a small agricultural field to evaluate the soil conservation practices. Nutrient losses occur in runoff and leachate (dissolved nutrient) and in sediments (particulate nutrient). Dissolved nitrates accounted for the majority (about 90%) of nitrate transport within the soil. Particulate phosphate in sediments represented the majority (60% to 67%) of phosphate transport. Recently, engineering and agronomic erosion-control practices haver been used to reduce erosion problems in fields on slopes. These practices reduced soil loss, runoff, and nutrient loss to 1/6, 1/2,and 1/3 their original levels, respectively. Bioavailable particulate phosphate in sediments represents a variable but longterm source of phosphate for algae. Dissolved nitrate and phosphate are immediately available for algal uptake, so reducing fluxes of these nutrients should also reduce the risk of eutrophication.

• Journal of the Korean Chemical Society
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• v.27 no.5
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• pp.361-367
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• 1983

The selective separation and the quantitative recovery of uranium from Korean monazite sand have been studied by anion-exchange chromatography. It has been shown that method of anion-exchange chromatography under controlled conditions of elution can be applied to the production of relatively high purity of Uranium Oxide from monazite sand. Under the optimum separation conditions, the recoveries from standard sample were up to 99.3% as $U_3O_8$ on sulfate form anion resin bed and 99.2% as $U_2O_3{\cdot}P_2O_7$ on phosphate form anion resin bed. The possibility of recovering uranium from the monazite sulfate solution using a strong base anion exchange resin-Amberlite IRA-900. Uranium was successfully recovered about 92 percent. Phosphate ion did not seem to interfere with the process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.1
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• pp.136-142
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• 2007

Recent publications have paid attention on the utilization of solid reagents for the removal of substances causing eutrophication, in particular $PO_4^{3-}$ ions. The adsorption of dissolved inorganic phosphate on slag produced by the refining process of iron ore was fundamentally studied for suppressing the liberation of phosphate from wastewater. This study has been conducted in order to find a possibility to improve the phosphate removal and to evaluate the phosphate removal variation to form hydroxyapatite, when the converter slag is used for phosphate removal. The result shows that the converter slag can be applied to remove phosphate using Freundlich isotherm. The size of converter slag, $2{\sim}0.425 mm$ was more efficient than $2{\sim}4.75mm$ to remove phosphate. In particular, 1 mg/L of phosphate can be removed up to 80% of the initial concentration for the continuous column experiment.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.3
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• pp.60-67
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• 2015

Objective of this study was to investigate adsorption characteristics of $PO_4-P$ to biochar produced from oak tree in respective to reduce eutrophication from runoff water in the cropland. For adsorption experiment, input amount of biochar was varied from 4 to 20 g/L with 30 mg/L $PO_4-P$ solution. Adsorption amounts and removal rates of $PO_4-P$ was increased at 3 times in 4~14 g/L, and increased at 28.6% in 4~16 g/L, respectively. The maximum adsorption amount ($q_m$) and binding strength constant(b) were calculated as 0.10 mg/g and 0.06 L/mg, respectively. The sorption of $PO_4-P$ to biochar was fitted well by Langmuir model because it was observed that dimensionless constant($R_L$) was 0.37. It was indicated that biochar is favorably adsorbed $PO_4-P$ because this value lie within 0 < $R_L$ < 1. Therefore, biochar produced from oak tree could be used as adsorbent for reduce eutrophication from runoff water in the cropland.

• Analytical Science and Technology
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• v.18 no.4
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• pp.355-361
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• 2005

The objective of this paper is to compare the surface features of two kinds of activated caron fiber (ACF) treated with potassium and the variation of their properties by phosphoric acid pre-treatment. X-ray diffraction (XRD) patterns indicate that activated carbon fiber containing potassium species show better performance for metal and metal salts by pre-treatment with phosphoric acid. In order to present the causes of the differences in surface properties and specific surface area after the samples were treated with phosphoric acid, pore structure and surface morphology were investigated by adsorption analysis and SEM. For the chemical composition microanalysis for potassium leading of the activated carbon fibers pre-treated with phosphoric acid, samples were analyzed by EDX. Finally, the type and quality of oxygen groups were determined from the method proposed by Boehm.

• Clean Technology
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• v.13 no.3
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• pp.215-221
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• 2007

Biosorption is considered to be a promising alternative to replace the present methods for the treatment of dye-containing wastewater. In this study, sewage sludge was used as a biosorbent which could be one of the cheapest and most abundant biomaterials. The objective of this work is to develop a surface-modified biosorbent with enhanced sorption capacity and binding affinity. The FT-IR and potentiometric titration studies revealed that carboxyl, phosphateand amine groups played a role in binding of dye molecules. The binding sites for reactive dye Reactive Red 4 (RR 4) were identified to be amino groups present in the biomass. In this work, based on the biosorption mechanism, the performance of biosorbentcould be enhanced by the removal of inhibitory carboxyl groups from the biomass for practical application of the biosorbents. As a result, the maximum capacity of biomass was increased up to 130% and 210% of the increment of sorption capacity at pH 2 and 4, respectively. Therefore, chemically modified sewage sludge can be used as an effective and low-cost biosorbent for the removal of dyes from industrial discharges.

• Analytical Science and Technology
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• v.8 no.1
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• pp.25-32
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• 1995

Determination method of trace thioglycolate has been studied by adsorptive stripping voltammetry. Copper(II)-thioglycolate complex is adsorbed at the hanging mercury drop electrode and stripped during cathodic scan. Electrolyte was used pH 6.5 phosphate and pH 9.5 borate buffer solutions. Optimal conditions were a copper(II) concentration $1{\times}10^{-4}M$, an adsorption accumulation potential -0.2V, an adsorption accumulation time 60 sec and a scan rate 20mV/sec. A detection limit of $1{\times}10^{-9}M$ thioglycolate was obtained. The method was applied to the determination of thioglycolate in cold wave fluids and depilating creams.

• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.231-237
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• 2016

The purpose of this study is to analyze phosphate adsorption characteristic of the filter media applied in water purification technology. And it is also to observe the removal efficiency of the technology that was developed by combining the purification abilities of filter media and the vegetation mat. The filter media, Adphos, is the subject of this study. The result of adsorption test shows that $PO_4{^{3-}-P}$ adsorption characteristics of Adphos is determined by the Langmuir isotherm model fitting and the $q_m$ (maximum adsorption amount) value is calculated as 1.162 mg/g. To verify the removal efficiency of the purification technology, a lab-scale reactor, including a 400 mm depth of filter bed filled by Adphos, was manufactured. Yellow flag Iris (Iris pseudacours L.) was planted on the vegetation bed and the coir-roll was used to fix the root of vegetation. The reactor ran 8 hours per day over 71 days, and the results of filtration experiment show that average removal efficiency of SS, T-N and T-P were calculated as 94%, 41% and 64% respectively. With these results, it was proved that the purification technology is highly effective. And for the long-time use, a maintenance guide is also required.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5370-5375
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• 2011

To introduce the antibacterial activity, ACF(activated carbon fiber) was impregnated by nano-sized Ag, Mn, and phosphoric acid. It was observed by the SEM analysis that Ag, Mn and phosphoric acid were properly impregnated at the ACF. The impregnated ACF showed lower adsorption performance than the pure ACF. It is found that ACFs impregnated by nano-sized Ag or phosphoric acid have a good antibacterial activity against bacillus cereus and salmonella entaritidis. but in the case of ACF impregnated with Mn, it have not any antibacterial effect on the bacillus cereus and salmonella entaritidis.

• Journal of the Korean Chemical Society
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• v.65 no.3
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• pp.197-202
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• 2021

In this study, activated clay treated with H₂SO₄ (20% by weight) and heat at 90 ℃ for 8 h for acid white soil was used as an adsorbent for the removal of PO₄^3--P in water. Prior to the adsorption experiment, the characteristics of activated clay was examined by X-ray Fluorescence Spectrometry (XRF) and BET surface area analyser. The adsorption of PO₄^3--P on activated clay was steeply increased within 0.25 h and reached equilibrium at 4 h. At 5 mg/L of low PO₄^3--P concentration, roughly 98% of adsorption efficiency was accomplished by activated clay. The adsorption data of PO₄^3--P were introduced to the adsorption isotherm and kinetic models. It was seen that both Freundlich and Langmuir isotherms were applied well to describe the adsorption behavior of PO₄^3--P on activated clay. For adsorption PO₄^3--P on activated clay, the Freundlich and Langmuir isotherm coefficients, K_F and Q, were found to be 8.3 and 20.0 mg/g, respectively. The pseudo-second-order kinetics model was more suitable for adsorption of PO₄^3--P in water/activated clay system owing to the higher correlation coefficient R² and the more proximity value of the experimental value q_e,exp and the calculated value q_e,cal than the pseudo-first-order kinetics model. The results of study indicate that activated clay could be used as an efficient adsorbent for the removal of PO₄³-P from water.