• The Korean Journal of Food And Nutrition
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• v.10 no.3
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• pp.295-301
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• 1997

Among 120 microorganisms isolated from soil, KF-67 was the best producer of flocculant and was examined for flocculating ability in the kaolin clay and CaCl2 suspension. KF-67 was identified to be a species belong to the genus Agrobacterium sp. The influence of components of the culture medium for flocculant production by Agrobacterium sp. KF-67 was studied. The favorable carbon and inorganic nitrogen source for production of the flocculant were glucose and NH4NO3 and their addition concentrations were 2% and 0.1%, respectively. Addition of the organic nitrogen such as yeast extract, peptone and inorganic salt such as CaCO3 significantly increased the production of flocculant. These result indicated that the production of flocculant by Agrobacterium sp. was significantly affected by both organic nitrogen and inorganic salt. The components of the optimum culture medium were 2% glucose, 0.1% NH4NO3, 0.01% yeast extract, 0.01% peptone, 0.04% CaCO3, 0.03% NaCl in initial pH 7.5 when cultured with rotary shaker controlled at 3$0^{\circ}C$ and 120 rpm. Under the optimum culture medium, flocculant production was highly improved about 76% than that isolation medium.

• KSBB Journal
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• v.10 no.4
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• pp.421-427
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• 1995

A fungal strain, designated Aspevgillus sp. JS-42, was isolated and shown to produce an extracellular polysaccharide used as a bioflocsulant. The optimal medium composition for the production of flocculant with Aspergillus sp. JS-42 was glucose 3.0%, yeast extract 0.2%, $(NH_4)_2S0_4 0.1%, CaCI_2.2H_2 0.05%$ in distilled water. The optimum culture temperature and optimum culture pH for the production of the flocculant were $25^{\circ}C$ and pH 7.0, respectively. The highest production of flocculant was observed after 90 hours of cultivation at the optimal condition. The flocculant could efficiently flocculaled the tested solids suspended in aqueous solution and was stable at high temperature($100^{\circ}C$) and to pH range of from 2 to 10. The flocculant seems to be a kind of high viscous polysaccharide.

• Applied Chemistry for Engineering
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• v.32 no.2
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• pp.139-142
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• 2021

Coal-fired power plants use coal as the main raw material, and when a coal is moved, a dust generation and spontaneous ignition of coal occur. To prevent this, water is sprayed. As a result, wastewater called "coal-dust water" flows out of coal dust and water mixed together, causing environmental pollution. In this study, in order to solve this problem, we developed a natural flocculant that can purify water by aggregating fine dust using chitosan and tried to prove its applicability. It was found that the optimum flocculation concentration was 4 ppm by adding various concentrations of flocculant to the coal-dust water, and it was confirmed that the developed material had very good coal-dust flocculation capacity through permeability and coal-dust removal efficiency. In addition, the cytotoxicity of the flocculant was evaluated through the MTT assay and it was found that there is no toxicity at all. We believe that the flocculant developed in this study can effectively adsorb coal-dust without affecting human and natural ecosystems.

• Environmental Engineering Research
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• v.7 no.4
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• pp.191-198
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• 2002

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.542-547
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• 1998

Polyamine type polymer flocculants were synthesized and their characterization, viscosity and flocculation studies were conducted. In order to increase the molecular weight of polyamine flocculant which was prepared by polycondensation reaction from dimethylamine and epichlorohydrin, a small amount of 1,6-hexanediamine was employed. The incorporation of 1,6-hexanediamine up to 5.5 mole % replacing corresponding part of dimethylamine gave a branched type polyamine sample with increased intrinsic viscosity ([${\eta}$]=0.46 in 1 wt % aqueous NaCl solution). The amount of 1,6-hexanediamine above 5.5 mole %, however, resulted in gelation during polymerization. Utilizing raw water from Maegok potable water treatment plant, it was found that the addition of polyamine flocculant at a concentration of 1 mg/L level could reduce the amount of polyaluminum chloride (PAC) inorganic flocculant by half (15 mg/L). It was also observed that the incoporation of polyamine flocculant at 1 mg/L level was effective in the higher pH raw water, while PAC inorganic flocculating agent alone was not effective.

• Environmental Engineering Research
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• v.11 no.5
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• pp.266-276
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• 2006

Commonly, the flocculant is dissolved in process or recycle water in industrial plant which has many ionic materials. Therefore, the polymer degradation in aqueous solution by chemical, mechanical or bacteriological may occur, sometimes rapidly. Even if the same flocculant is dissolved, the flocculation characteristics and the properties of dissolving polymer varied with the kind of dissolving water. In this study, we try to estimate the interaction between flocculants and ionic materials in dissolving water using self inversing emulsion polymer; polyacrylamide-co-trimethyl ammonium ethyl acrylate chloride flocculants which have varying molecular weights and structures at a several conditions. The polymeric flocculant is dissolved in artificial dissolving water with Potassium Chloride (PC), Calcium Chloride anhydrous (CC), Potassium Hydroxide (PH), Sodium Chloride (SC), Sodium Bromate (SB) and Iron (II) Sulfate Heptahydrate (IS) as ionic sources. Experimental results indicate that the cationic and anionic ions in dissolving water induce the hydrolysis, degradation of cationic functional group and uncoiling of polymeric flocculants, therefore, the flocculation efficiency decreased by undesired polymer. According that result, it is important to estimate not only its structures and physical properties but also the qualities of dissolving water to optimize the efficiency.

• Microbiology and Biotechnology Letters
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• v.27 no.6
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• pp.433-439
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• 1999

Among microorganisms isolated from soil, YJ-66 strain was the best producer of flocculant and was examined for flocculating ability in the active carbon and CaCl2. YJ-66 strain was the best producer of flocculant and was examined for flocculating ability in the active carbon and CaCl2. YJ-66 strain was identified to be a species belonging to the genus Achromobacter. The optimum culture condition for production of bioflocculant with the isolated strain was for 72hrs at 3$0^{\circ}C$ and pH7.5. The favorable carbon, nitrogen sources and inorganic salts for production of the flocculant were sucrose, peptone, MgSO4 and KH2PO4, whose optimal concentrations were 2%. 0.067%, 0.1% and 0.1%, respectively. Addition of the carbon and inorganic salts significantly increased the production of flocculant. Compositions of optimized culture medium for bioflocculant production by Achromobacter sp. YJ-66 were 2% sucrose, 0.067% peptone, 0.1% MgSO4 and 0.1% KH2PO4 in initial pH 7.5 during at 3$0^{\circ}C$ for 72hrs.

• Environmental Engineering Research
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• v.11 no.4
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• pp.208-216
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• 2006

In order to create a single flocculant/dual flocculation system, polyacrylamide-co-trimethyl ammonium ethyl acrylate chloride (TAEAC) polymers with varying molecular weights and structures were prepared for use of flocculants. The higher the cationic density of the polymer is higher, the higher was the conversion rate and the ratio of monomer. An acrylamide as nonionic monomer was less reactive than a TAEAC as cationic monomer. The branched polymer which was polymerized with a cross-linking agent, N, N-methylene bis-acrylamide had a higher stability and higher viscosity than a linear polymer but its dewatering efficiency was poor in a single flocculation system. In the case of single flocculant/dual flocculation, the branched polymer has better flocculation efficiency and the water content of the dewatered cakes was lower than the others, as the result of a re-flocculation effect. The optimum conditions for dual flocculation are a sequence in which the $1^{st}$ and $2^{nd}$ dosage are 75% and 25%/total dosage of a single flocculation system. The dewatering efficiency of a dual flocculation system is improved considerably from 10 to 25% under the experimental conditions used herein.

• KSBB Journal
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• v.29 no.3
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• pp.220-224
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• 2014

Flocculation is known one of the effective methods for harvesting microalgae. This study was aimed to optimize the flocculation condition for decreasing the amounts of flocculant and obtaining the highest yield of algal biomass. To achieve this goal, it was optimized the flocculant concentration, reaction pH and the concentration of cell density for harvest using response surface methodology (RSM). The flocculation of microalgae, Spirogyra varians, was carried out using inorganic flocculant polyaluminium chloride. By the RSM result, the optimal flocculation condition was calculated 5 ppm of polyaluminum chloride, pH 7.5 and 0.33 of optical cell density at $OD_{640}$. The obtained recovery yield of S. varians was 97.6% at the optimal condition.

• Journal of Korean Society on Water Environment
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• v.31 no.6
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• pp.625-631
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• 2015

In this study, low cost bio-flocculants, chitosan, cationic starch and Mg-sericite, were used as a flocculant to harvest freshwater microalgae, Chlorella vulgaris. Chitosan, cationic starch and Mg-sericite separated successfully >98% of C. vulgaris at following optimal parameters: 90 mg/L chitosan at pH 6-7, 70 mg/L cationic starch at pH 9-10 and 50 mg/L Mg-sericite at pH 4-5. A relatively high correlation coefficient (R²) of 0.9993 for chitosan, 0.9971 for catonic starch and 0.9924 for Mg-sericite was obtained. The investigated flocculants amount increased linearly with increasing the microalgae amount. The biopolymer, Mg-sericite, was more effective than that of other investigated flocculants. These results indicated that a bio-flocculants, chitosan, cationic starch and Mg-sericite, could prove to be an effective flocculant for economical production of microalgae biomass. In addition, Mg-sericite was more effective comparing to the other investigated flocculants.