• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.09a
• /
• pp.123-127
• /
• 2003

Changes in pyrene partitioning due to mineral surface adsorptive fractionation processes of humic substances (HS) were examined in model environmental systems. For purified Aldrich humic acid(PAHA), carbon-normalized pyrene binding coefficients ( $K_{oc}$ ) for the residual (i.e., nonadsorbed and dissolved) PAHA components were different from the original dissolved PAHA $K_{oc}$ , value prior to contact with mineral suspensions. A positive correlation between the extent of pyrene binding and weight-average molecular weight (M $W_{w}$) of residual PAHA components was observed, which appeared to be unaffected by the specific mineral adsorbents use and fractionation mechanisms. A similar positive correlation was not observed with the adsorbed PAHA components, suggesting that conformational changes occurred for the mineral-associated components upon adsorption. Nonlinear pyrene sorption to mineral-associated PAHA was observed, and the degree of nonlinearity is hypothesized to be dependent on adsorptive fractionation effects and/or structural rearrangement of the adsorbed PAHA components.s.

• Bulletin of the Korean Chemical Society
• /
• v.12 no.2
• /
• pp.153-156
• /
• 1991

Three humic acids, two from uranium bearing coal shale and one from the neighbouring limey shale region, are extracted from soils by dissolution in 0.1 M NaOH followed by acid precipitation. After purification cycles, they are characterized for their elemental composition, contents of inorganic impurities, molecular size distribution and proton exchange capacities. The results are compared with the data of reference and aquatic humic acids characterized under the project MIRAGE Ⅱ at TUM and also with other literature data. The proton exchange capacity determined by direct titration, is found to be 3.60 and 2.01 meq/g for coal shale and limey shale humic acids, respectively.

• Journal of Environmental Health Sciences
• /
• v.25 no.3
• /
• pp.83-88
• /
• 1999

This study was carried out to examine the behavior of THM formation in water treated with chlorine dioxide where humic acid was used as THM precursor. THM was not detected in bromide-free water, but formed in water containing bromide. When 10 mg/l of chlorine dioxide was added to water containing 5 mg/l of humic acid and bromide respectively, 20.46 ${\mu}$g/l of THM was formed. It is postulated that chlorine dioxide oxidize bromide to hydrobromous acid, which subsequently reacted with humic acids similar to chlorine reaction. The formation of THM could be reduced at low pH. Among THM formed, CHBr$_3$ was the predominant species in the alkaline solution, while CHCl$_3$ in the acidic solution. A sample pretreated with chlorine dioxide for 24h before addition of chlorine showed a reduction of 75.1% in THM formation, compared with a sample not pretreated with chlorine dioxide and a sample treated by chlorine for 24h prior to addition of chlorine dioxide also showed a reduction of 37.8% in THM formation, compared with a sample not added with chlorine dioxide. It may explain that chlorine dioxide oxidizes directly a fraction of THM.

• Membrane and Water Treatment
• /
• v.9 no.6
• /
• pp.385-392
• /
• 2018

Poly vinyl chloride (PVC) was chemically modified, and used for ultrafiltration to analyze the performance. Non-solvent induced phase separation (NIPS) method was used to prepare membranes. The neat PVC membrane was casted and used as a control membrane. Modified membrane was prepared by reacting PVC with ethanolamine (EA) in the casting solution (labeled as CM-PVC). Pure water permeability (PWP) was evaluated by measuring pure water flux. Humic acid was used as model foulant solute to analyze flux and rejection ability of membranes. Flux and rejection data of neat and modified membranes were compared to prove the improvement in the filtration performance. The experimental results showed that for PVC and CM-PVC, PWP was calculated to be ~64 and ${\sim}143L/m^2{\cdot}h$, respectively, and the rejection of humic acid was found to be 98% and 100%, respectively. TGA was carried out to analyze the effect of chemical modification on the thermal stability of polymer. FT-IR analysis was another characterization technique used for the comparative study.

• Environmental Engineering Research
• /
• v.16 no.3
• /
• pp.149-157
• /
• 2011

Nanofiltration (NF) experiments were conducted to investigate fouling of Al-hydroxide precipitate and the influence of organic compound, inorganic compound, and their combination, i.e., multiple foulants. $CaCl_2$ and $MgSO_4$ were employed as surrogates of inorganic compounds while humic acid was used as surrogate of organic compound. The flux attained from NF experiments was fitted with the mathematical fouling model to evaluate the potential fouling mechanisms. Al-hydroxide fouling with a cake formation mechanism had little effect on the NF membrane fouling regardless of the Al concentration. The NF fouling by Al-hydroxide precipitate was deteriorated in presence of inorganic matter. The effect of Mg was more critical in increasing the fouling than Ca. This is because the Mg ions enhanced the resistances of the cake layer accumulated by the Al-hydroxide precipitate on the membrane surfaces. However, the fouling with Mg was dramatically mitigated by adding humic acid. It is interesting to observe that the removal of the conductivity was enhanced to 61.2% in presence of Mg and humic acid from 30.9% with Al-hydroxide alone. The influence of dissolved matter (i.e., colloids) was more negative than particulate matter on the NF fouling for Al-hydroxide precipitate in presence of inorganic and organic matter.

• Mycobiology
• /
• v.39 no.4
• /
• pp.290-298
• /
• 2011

The ability of benzothiadiazole (BTH) and/or humic acid (HA) used as seed soaking to induce systemic resistance against a pathogenic strain of Fusarium oxysporum was examined in four soybean cultivars under greenhouse conditions. Alone and in combination the inducers were able to protect soybean plants against damping-off and wilt diseases compared with check treatment. These results were confirmed under field conditions in two different locations (Minia and New Valley governorates). The tested treatments significantly reduced damping-off and wilt diseases and increased growth parameters, except the number of branches per plant and also increased seed yield. Application of BTH (0.25 g/L) + HA (4 g/L) was the most potent in this respect. Soybean seed soaking in BTH + HA produced the highest activities of the testes of oxidative enzymes followed by BTH in the four soybean cultivars. HA treatment resulted in the lowest increases of these oxidative enzymes. Similar results were obtained with total phenol but HA increased total phenol more than did BTH in all tested cultivars.

• Journal of Korean Society of Water and Wastewater
• /
• v.30 no.6
• /
• pp.737-744
• /
• 2016

The investigation of effects on fouling propensity with various viscosity of feed solutions would be better understanding for forward osmosis (FO) performance since the fouling propensity was directly influenced with solution viscosity. Therefore, this study was focused on the FO fouling with model foultants (humic acid, alginate) by altering solution viscosity with change of ionic strength (I.S) and $Ca^{2+}$ concentrations. In the comparison between humic acid and alginate, as expected, the alginate generally caused more severe fouling (almost 35.8 % of flux reduction) based on the solution characteristics (high viscosity) and fouling patterns (coil and gel layer). However, interesting point to note is that the fouling propensity of alginate was more severe even though it was applied with low viscosity of feed conditions (I.S = 20 mM, $Ca^{2+}=1mM$). This might be due to that crossed linked gel layer of alginate on the FO membrane surface could be best formed in the condition of $Ca^{2+}$ presence and higher I.S, and that is more dominant to fouling propensity than the low viscosity of feed solutions.

• Membrane Journal
• /
• v.29 no.5
• /
• pp.276-283
• /
• 2019

In this study, The experiments of the confirmation of the fouling phenomena in CDI process and the establishment of its removal process conditions were carried out. The foulant concentrations of humic acid sodium salt (HA) added to the feed solution were 5, 10, 15 mg/L, respectively. The occurrence of fouling under the certain adsorption/desorption conditions could be confirmed with an increase in adsorption and desorption concentration curve over time. Both the voltage and time in adsorption and desorption processes were changed to eliminate the fouled pollutants. Typically, the fouling removal condition was found at the adsorption condition 1.2 V/5 min and the desorption condition -3 V/2 min, respectively.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.12
• /
• pp.1321-1326
• /
• 2005

As a results of this research, the Nakdong River consisted of 43% of hydrophobic fraction, 39% of hydrophilic fraction, and 18% of transphilic fraction. The hydrophobic fraction in this raw water was mostly fulvic acid. Fulvic acid comprised of 62% and the rest was humic acid(38%). There was more carboxylic acid functional roup(64%) than phenolic group(36%). HPI-N and HPI-C comprised of 17% and 22% in the hydrophilic portion, respectively. The results of the membrane fouling test using UF membrane according to NOM fractions. HPI-N caused more fouling than HPI-C. Humic acid caused more fouling than fulvic acid probably due to higher adsorption capacity. Since humic acid has higher adsorption capacity than fulvic acid, it would be more adsorbed onto the membrane pores. The carboxylic acid functional group caused more fouling than the phenolic group.

• Korean Journal of Soil Science and Fertilizer
• /
• v.22 no.1
• /
• pp.31-38
• /
• 1989

A series of experiments was conducted to determine the contents and distribution of amino acids in the hydrolysates of humic acids extracted from 3 plant materials. Wild grass hay, and leaves of forest trees were used in this study. Seventeen amino acids were analyzed and their amounts determined. Results obtained from the experiments are summarized in the following: 1. Contents and distribution of hydrolyzable amino acids in the humic acid fractions depend on the kind of plant materials and the allowed time for humification. 2. Neutral amino acids was the largest part of the total amino acids, followed by acidic amino acids, and basic amino acids. 3. The total amounts of amino acids in the hydrolyzable humic acid fractions of well humified residues were in the following order: wild grass hay > leaves of deciduous trees > leaves of coniferous trees 4. In general the relative amounts of lysine increased with humification progressing. S. Glycine and glutamic acid were the two major amino acids in common for the hydrolysate of humic acids extracted from well decomposed residues of plant materials. Alanine, glutamic acid, glycine, aspartic acid and leucine were the five major amino acid in common in raw materials without exception. 6. Arginine appeared to be absent in any of the hydrolysates of humic acids from well humified plant materials. 7. Phenylalanine and tyrosine were present in all hydrolysates and their relative contents increased with the humification of plant materials.