• Advances in environmental research
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• v.9 no.1
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• pp.65-84
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• 2020

The potential use of Sargassum boveanum algae for the removal of uranium from aqueous solution has been studied by varying three independent parameters (pH, initial uranium ion concentration, S. boveanum dosage) using a central composite design (CCD) under response surface methodology (RSM). Batch mode experiments were performed in 20 experimental runs to determine the maximum metal adsorption capacity. In CCD design, the quantitative relationship between different levels of these parameters and heavy metal uptake (q) were used to work out the optimized levels of these parameters. The analysis of variance (ANOVA) of the proposed quadratic model revealed that this model was highly significant (R² = 0.9940). The best set required 2.81 as initial pH(on the base of design of experiments method), 1.01 g/L S. boveanum and 418.92 mg/L uranium ion concentration within 180 min of contact time to show an optimum uranium uptake of 255 mg/g biomass. The biosorption process was also evaluated by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models represented that the experimental data fitted to the Langmuir isotherm model of a suitable degree and showed the maximum uptake capacity of 500 mg/g. FTIR and scanning electron microscopy were used to characterize the biosorbent and implied that the functional groups (carboxyl, sulfate, carbonyl and amine) were responsible for the biosorption of uranium from aqueous solution. In conclusion, the present study showed that S. boveanum could be a promising biosorbent for the removal of uranium pollutants from aqueous solutions.

• Journal of Environmental Science International
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• v.6 no.1
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• pp.61-67
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• 1997

Heavy metal adsorption by microbial cells is an alternative to conventional methods of heavy metal removal and recovery from metal-bearing wastewater The waste Sac-chuomyces cerevisiae is an inexpensive, relatively available source of biomass for heavy metal biosorption. Biosorption was investigated by free and immobilized-S. cerevisiae. The order of biosorption capacity was Pb>Cu>Cd with batch system. The biosorption parameters had been determined for Pb with free , cells according to the Freundlich and Langmuir model. It was found that the data fitted reasonably well to the Freundlich model. The selective uptake of immobilized-S. cerevisiae was observed when all the metal ions were dissolved in a mixed metals solution(Pb, Cu, Cr and Cd). The biosorption of mixed metals solution by immobilized-cell was studied in packed bed reactor. The Pb uptake was Investigated in particular, as it represents one of the most widely distributed heavy metals in water. We also tested the desorption of Pb from immobilized-cell by us- ing HCI, $H_2SO_4$ and EDTA.

• Economic and Environmental Geology
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• v.43 no.3
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• pp.223-233
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• 2010

The effects of extracellular polymeric substances (EPS) of Pseudomonas aeruginosa on adsorption and redox state alteration of dissolved As, Cr and U were investigated through batch experiments. Surfaces of bacterial cells were either vigorously washed or unwashed. Solutions of As(V), Cr(VI) and U(VI) were inoculated with the bacterial cells under no nutrient condition, and total aqueous concentrations and redox state alteration were monitored over time. No As adsorption occurred onto bacteria or EPS; however, unwashed bacteria reduced about 60% As(V) to As(III). Unwashed bacteria also led to removal of 45% total dissolved Cr and reduction of 64% Cr(VI). About 80% U(VI) was removed from solution with unwashed bacteria as well. Such electrochemical reduction of the elements was likely due to reducing capacity of EPS itself or detoxifying reduction of the bacteria which kept their viability under protection of EPS. The results indicated that bacterial biofilm may significantly control the redox state and subsequent mobility of As, Cr and U in natural geologic settings.

• KSBB Journal
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• v.15 no.4
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• pp.375-379
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• 2000

Alginate derivatives possessing various lengths of alkyl amine (C8, C12, C16) chain were prepared by oxidation followed by reductive amination of alginate and the products were characterized by spectral analysis. The surface tension critical micelle concentration (c. m. c) and solubility of a hydrophobic compound azobenzene were examined. Series of synthesized alginate-derived polymeric surfactants(APSs) reduced the surface tension. The dissolving capacity of APSs toward azobenzene was about half that of SDS. In order to investigate the capacity of metal adsorption Co and Pb were selected as a representative metal. The overall removal efficiency of APSs were high compared with that of alginate at pH 3.5 and 7 respectively. Major mechanism of the heavy metal removal is the complex of metal with carboxyl group.

• Journal of Wetlands Research
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• v.26 no.2
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• pp.168-181
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• 2024

Constructed wetlands (CWs) deliver a range of ecosystem services, including the removal of contaminants, sequestration and storage of carbon, and enhancement of biodiversity. These services are facilitated through hydrological and ecological processes such as infiltration, adsorption, water retention, and evapotranspiration by plants and microorganisms. This study investigated the correlations between microbial populations, soil physicochemical properties, and treatment efficiency in a horizontal subsurface flow constructed wetland (HSSF CW) treating runoff from roads and parking lots. The methods employed included storm event monitoring, water quality analysis, soil sampling, soil quality parameter analysis, and microbial analysis. The facility achieved its highest pollutant removal efficiencies during the warm season (>15℃), with rates ranging from 33% to 74% for TSS, COD, TN, TP, and specific heavy metals including Fe, Zn, and Cd. Meanwhile, the highest removal efficiency was 35% for TOC during the cold season (≤15℃). These high removal rates can be attributed to sedimentation, adsorption, precipitation, plant uptake, and microbial transformations within the CW. Soil analysis revealed that the soil from HSSF CW had a soil organic carbon content 3.3 times higher than that of soil collected from a nearby landscape. Stoichiometric ratios of carbon (C), nitrogen (N), and phosphorus (P) in the inflow and outflow were recorded as C:N:P of 120:1.5:1 and 135.2:0.4:1, respectively, indicating an extremely low proportion of N and P compared to C, which may challenge microbial remediation efficiency. Additionally, microbial analyses indicated that the warm season was more conducive to microorganism growth, with higher abundance, richness, diversity, homogeneity, and evenness of the microbial community, as manifested in the biodiversity indices, compared to the cold season. Pollutants in stormwater runoff entering the HSSF CW fostered microbial growth, particularly for dominant phyla such as Proteobacteria, Actinobacteria, Acidobacteria, and Bacteroidetes, which have shown moderate to strong correlations with specific soil properties and changes in influent-effluent concentrations of water quality parameters.

• Journal of the Korean earth science society
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• v.43 no.2
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• pp.303-311
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• 2022

Gadolinium, commonly used as a contrast agent for magnetic resonance imaging (MRI), is discharged into aquatic environments without removal after treatment in wastewater treatment plants (WWTPs) because of its high stability. In this study, we collected water samples from Suyeong WWTP, Busan, to investigate the dissolved rare earth element (REE) removal capacity of each wastewater treatment process and to evaluate the discharge of anthropogenic Gd (Gd_anth) from effluents. As wastewater passed through each stage of treatment, the concentrations of light REEs (La-Eu) decreased, whereas those of heavy REEs (Tb-Lu) were relatively consistent. Negative Sm anomalies (<1) were observed in several samples, indicating that Sm can be removed by adsorption onto particles or phosphate during the biological removal process. Positive Gd anomalies (149±50, n=9) were observed in all samples. The ratios of Gd_anth concentrations to measured Gd concentrations in all wastewater treatment processes were higher than 97%. This indicates that Gd_anth was discharged to the Suyeong River without removal during the wastewater treatment process. Considering the daily treatment capacity in each process, the total flux of Gd_anth was estimated to be 259 mmol/day. Our results suggest that mid- and/or long-term monitoring of Gd is needed because Gd_anth is continuously discharged into Suyeong Bay through WWTPs.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.203-210
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• 2000

The preparative methods of a chitosan-deposited activated carbon and its characteristics were studied by using three kinds of chitosan with different degree of deacetylation and average molecular weight. The procedure was consisted of the dissolution of chitosan into acid solution, impregnation of activated carbon, agitation, evaporation, and drying. When the chitosan-dissolved acid and its concentration, amounts of chitosan deposited, and agitation conditions were changed, the specific surface area, deposition state on surface, and stability were investigated, and amounts of Cr(VI) adsorbed was measured. In the preparation process, it was proper to agitate the chitosan-dissolved acetic acid solution at room temperature for 1hr. In the deposition of chitosan with low molecular weight, the specific surface area of activated carbon was greatly decreased even at low chitosan loading, but in the case of high molecular weight it was not nearly changed to 10wt% loading. It was known that chitosan was uniformly and physically deposited on activated carbon. The chitosan-deposited activated carbon was stable into the solution over about pH 6. The removal of Cr(VI) was remarkably enhanced by adding the adsorption function of chitosan to the surface of activated carbon with about 5wt% chitosan. It may be therefore used as an adsorbent for removing the pollutants in air and wastewater.

• Korean Journal of Veterinary Research
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• v.11 no.2
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• pp.123-136
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• 1971

(1) The non-specific inhibitors (NSI) in normal chicken sera were active against all the tested group A and group B arboviruses, but the group B arbovirus were more sensitive than group A arboviruses. (2) The titres of the NSI were distributed nearly uniformly among chickens from seven different age groups to group A arboviruses. In contrast, the NSI titres to group A arboviruses were found to increase with age. (3) No significant difference could be demonstrated between acetone-ether extraction and kaolin adsorption for removal of the NSI in normal chicken sera. (4) After heating, the NSI titres in chicken sera were increased for both group A and group B arboviruses. (5) After heating the sera at $80^{\circ}C$ and $100^{\circ}C$, kaolin adsorption was less efficient for removing the NSI than it, was in unheated serum. Acetone-ether extraction of the NSI was unimpaired after heating at $80^{\circ}C$ but was less efficient after heating at $100^{\circ}C$. (6) The NSI activity was found mainly in the first peak (IgM) and diffused to a part of second peak (IgG) by fractionation of chicken serum by gel filtration through Sephadex G200. After zonal centrifugation of chicken serum in a linear ten to 40 percent sucrose gradient all of the NSI activities were found on the top of the centrifugal tubes. These properties of large molecular size and low density indicated that the NSI in chicken serum were probably lipoproteins. (7) The natural agglutinins for goose erythrocytes in chicken sera were partially destroyed by acetone-ether extraction but not by kaolin adsorption, and were efficiently adsorbed with ten percent goose erythrocytes. No difference of the NA titre was demonstrated with diluents of different pH. (8) The NA in chicken serum was found to possess the properties of IgM by gel filtration through Sephadex G200 and zonal centrifugation in linear ten to 40 percent sucrose gradient.

• Microbiology and Biotechnology Letters
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• v.26 no.1
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• pp.83-88
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• 1998

Heavy metal removal by Z. ramigera 115 and soluble slime polymer producing mutant Z. ramigera 115SLR was investigated. Both strains showed similar tolerance against $Cd^{2+}$, $Co^{2+}$, $Cu^{2+}$, $Ni^{2+}$ and $Fe^{2+}$. When cells were cultivated in the presence of 500 ppm $Cd^{2+}$, the mutant strain removed 1.5 fold more metal than the wild type did at same biomass. Metal adsorption capacities were in the order of Z. ramigera l15SLR polymer > Z. ramigera 115 polymer > Z. ramigera 115 cell >Z. ramigera l15SLR cell. The optimum pH for metal adsorption was 7.5. Langmuir and Freundlich isotherms indicated that Qmax and 1/n of Z. ramigera l15SLR polymer were 164.2 mg $Cd^{2+}$/g dw and 0.496, respectively. These results showed that the polymer of Z. ramigera l15SLR could be used as an effective metal adsorbate.

• Journal of the Mineralogical Society of Korea
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• v.28 no.4
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• pp.299-308
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• 2015

The six natural zeolites collected in Pohang area, Kyungsangbuk-do, Korea, were characterized by XRD, XRF, DTA, TGA, and CEC analysis. The primary species of these zeolite are modenite, albite, and quarts in Kuryongpo-A (Ku-A), Kuryongpo-B (Ku-B), Kuryongpo-C (Ku-C), Donghae-A (Dh-A), Donghae-B (Dh-B), and Donghae-C (Dh-C) samples. The XRF analysis showed that the six zeolites contain Si, Al, Na, K, Mg, Ca, and Fe. Cation exchange capacity of Kuryongpo-C (Ku-C) zeolite was the highest compared to other zeolites. The capabilities of removing heavy metal ions such as $Pb^{2+}$, $Cd^{2+}$ and $Cu^{2+}$ were compared. The effect of reaction time in removing heavy metal ions was studied. The experimental results showed that the efficiency of removal was low for $Pb^{2+}$, $Cd^{2+}$ and $Cu^{2+}$ ions. These may be caused by the low content of zeolite in the six natural zeolites. This indicates that the adsorption capacity roughly tends to depend on the zeoite contents, ie., the grade of zeolite ore.