• Environmental Engineering Research
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• v.20 no.1
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• pp.41-50
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• 2015

The cyanobacterium Anabaena doliolum Ind1 isolated from a coal mining site was tested for removal of cadmium at optimum pH 7.0 and temperature $25^{\circ}C$. The organism recorded high percentage of metal removal (92-69%) within seven days of exposure to 0.5-2.0 ppm cadmium. Biosorption onto the cell surface was the primary mode of metal removal. Fourier transform infrared spectroscopy (FTIR) established hydroxyl, amides, carboxyl, sulphate and carbonyl groups to be the major functional groups on the cell surface involved in cadmium binding. Cellular ultrastructure and a range of vital physiological processes (i.e., photosynthetic pigments, respiration, photosynthesis, heterocyst frequency and nitrogenase activity) remained unaffected upon 0.5 ppm treatment; higher concentrations of cadmium exerted visible adverse effects. Amongst the five photosynthetic pigments tested, phycocyanin was the most targeted pigment (inhibition was 15-89%). Both respiration and photosynthetic activities were inhibited by cadmium with more severe effect seen on respiration. 2.0 ppm cadmium exposure also had drastic negative effect on nitrogenase activity (87% decreased).

• Journal of Electrochemical Science and Technology
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• v.12 no.1
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• pp.58-66
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• 2021

Spiral-wound woven wire meshes packed bed rotating cylinder electrode was used for the simultaneous removal of cadmium (Cd) and copper (Cu) from a binary solution. The effects of weight percent of each metal on the removal and current efficiencies were studied at an operating current of 345A, while the effect of current on the removal efficiency of both metals was investigated at three levels of current (240, 345.and 400 mA). The experiments were carried out at constant rotation speed 800 rpm, pH = 3, and a total concentration of metals (500 ppm). The results showed that the removal efficiency of copper increased from 89% to 99.4% as its weight percent increased from 20% to100%. In a similar fashion, the removal efficiency of cadmium increased from 81% to 97% as its weight percent increased from 20% to100%. The results confirmed that the removal efficiency of any metals declined in the presence of the other. Increasing of current resulted in increasing the removal efficiency of both metals at different weight percents. The results confirmed that current efficiencies for removing of copper and cadmium simultaneously decline with increasing of electrolysis time and weight percent of cadmium or with decreasing the weight percent of copper. Current efficiency was higher at the initial stage of electrolysis for all weight percents of metals. The results showed that the decay of copper concentration was exponential at all weight percents of copper, confirming that the electrodeposition of copper is under mass transfer control in the presence of cadmium. While the decay of cadmium concentration was linear at lower weight percent of cadmium then changed to an exponential behavior at high weight percent of cadmium in the presence of copper.

• Journal of environmental and Sanitary engineering
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• v.19 no.1
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• pp.37-41
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• 2004

The removal efficiency of cadmium by chitosan complex isolated from Aspersillus oryzae was investigated through laboratory experiments. The results of the study are as follows. The adsorption kinetics of cadmium was reached the adsorption equilibrium in approximately 20 minutes and the removal efficiency was showed 95.8%. The effect of temperature on cadmium adsorption by chitosan complex shows that as the temperature increased, the amount of cadmium adsorption per unit weight of chitosan complex increased. The correlation between amount of cadmium adsorption per unit weight of chitosan complex and temperature was obtained through the coefficient of determination($R^2$). $R^2$ values was 0.854(p<0.05). A linearized Freundlich equation was used to fit the acquired experimental data. As a result, Freundlich constant, the adsorption intensity(1/n) was 0.550, and the measure of adsorption(k) was 2.181. So, it was concluded that adsorption of cadmium by chitosan complex is effective.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.5
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• pp.784-791
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• 1994

This study was to investigate the cadmium removal effect of Korean green tea, black tea and oolong tea beverage on Cd administered rat, tissues and their excretions. Male Sprague-Dawley rats weighing 143±3.2g were divided into control and experimental groups. The control group were fed standard diet without cadmium . The experimental groups, which were fed standard diet containing 40 ppm Cd, were divided into 4 subgroups again , which were the groups given distilled water (CD group), 5% black tea (BT group), oolong tea (OT group ) and green tea (GT group), respectively. Five days before to sacrifice the rats, all 4 cadmium fed groups were supplied 1 ml of water with 600ppm Cd and control group were fed 1 ml of distilled water without Cd under the same dietary condition. After that, their excretion were collected separately for 3 days. In rat liver and kidney, accmulation of cadmium in 4 Cd administered groups were more than in control group and that of GT group was significantly less than CD group. In bone , also, accumulation of cadmium in 4 Cd administered groups was more than in control group and that of GT, OT,BT groups were much less than that of CD group. GT group was excreted more Cd in urine than Cd group. In feces, 3 tea feeding groups (BT, OT, GT group) were excreted Cd 1.7, 2.1, 2.4 times more than that of the CD group, respectively. We conclude that cadmium accumulations of GT feeding group in rat's liver, kidney and bone were much less than CD group , and the absorption and retention rate of GT group was significantly lower than CD group.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.740-744
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• 1994

This study was undertaken to prove the suppressing effect of green tea on the intestinal absorption of heavy metals using in vitro membrane filtration system. From drinking water contaminated with 10 and 100 times level of water quality standard for heavy metals, the removal ratio of lead (Pb) was $50{\sim}70%$ by green and black teas, and $30{\sim}40%$ by roasted barley tea. The removal ratio of cadmium (Cd) was $30{\sim}40%$ by green tea and black teas, and $10{\sim}20%$ by roasted barley tea. The removal effect from drinking water contaminated with both lead and cadmium was lower than that from water contaminated singly with lead or cadmium. It appears that tea components and filter membrane compete toward the adsorption of two heavy metals. Among the extraction conditions of raw tea materials at $70^{\circ}C$, 2 minutes and $95^{\circ}C$ , 10 minutes, the removal ratios of heavy metals were similar.

• The Korean Journal of Ecology
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• v.19 no.6
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• pp.519-527
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• 1996

To examine the possibility of biomonitoring of heavy metal removal ability and soil, a study was performed to investigate the heavy metal removal ability and metal-binding protein (MBP) as detoxification process using Oenanthe stolonifera. After O. stolonifera was exposed to individuals (cadmium, zinc) and mixture (cadmium+zinc)for 4 days, removal rate of heavy metal and pH in the treatment medium was measured. MBP was assayed by means of ion exchange column chromatography. The exposure to mixture (Cd:76.8%, Zn:75%) rather than individuals (Cd:82.9%, Zn:90.4%) showed a synergism raising the toxic effect. Initial removal rate was different for each heavy metal : in case of exposure to cadmium it was over 60% on day 1, while for zinc it was 75~90% on day 4. Throughout the experimental period, pH value of treatment medium continuously decreased, since cortex in the roots may secret organic acid to adjust and prevent toxicity of metals. The existence or MBP in the 70~80 fraction and the presence of Zn-enzyme pool was ascertained with the column chromatography. This study demonstrated a possibility that heavy utilized as a biomarker of heavy metal pollution.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.1
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• pp.69-74
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• 2015

Cadmium telluride (CdTe) is being developed for thin film of the X-Ray detector recently. But a rough surface of the CdTe should be improved for resolution and signal speed. This paper shows the study on the improvement of surface roughness and removal rate by applying Chemical Mechanical Polishing. The conventional potassium hydroxide (KOH) based colloidal silica slurry could not realize a mirror surface without physical defects, resulting in low material removal rate and many scratches on surface. In order to enhance chemical reaction such as form oxidized layer on the surface of cadmium telluride, we used hydrogen peroxide ($H_2O_2$) as an oxidizer. Consequently, in case of 3 wt% concentration of hydrogen peroxide, the highest MRR (938 nm/min) and the lowest surface roughness ($R_{p-v}=10.69nm$, $R_a=0.8nm$) could be obtained. EDS was also used to confirm the generated oxide of cadmium telluride surface.

• Membrane Journal
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• v.13 no.4
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• pp.211-218
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• 2003

The removal characteristics of cadmium in micellar enhanced ultrafiltration (MEUF) were investigated by using an anionic biosurfactant, deoxycholic acid (DCA). The ultrafiltration experiments were performed in a batch-type stirred cell. The ultrafiltration membranes used were Millipore YM1, YM3, YM10, and YM30 which had a difference in molecular weight cut-off. The presence of cadmium ion in DCA solution tends to reduce the critical micell concentration considerably and increase the micell size. The molecular weight cut-off of ultrafiltration membrane had a minimal effect on cadmium removal whereas DCA/Cd ratio had a substantial influence. When DCA/Cd ratio was 3, the removal efficiency of cadmium was more than 99.6%. A relative flux, which is defined as ratio of the flux for a separation trial to that of deionized water run using the same piece of membrane, decreased in the order of YM3 > YM1 > YM10 > YM30.

• Applied Biological Chemistry
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• v.43 no.3
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• pp.213-217
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• 2000

In order to investigate the removal effect of cadmium by polyphenol compound extracted from persimmon leaves(Diospyros kaki folium), animal test was done. Two fractions such as F-1 and F-2 from persimmon leaves were compared with their safety and function. The food intake of group F-1 and F-2 considerably decreased within 1% level. Cadmium addition influenced to rat growth(a tested animal), but food efficiency ratio(FER) wasn't shown any considerable difference in F-1 and F-2, as compared to the control. Cadmium content of liver, kidney and femur considerably decreased within 1% level in F-1 and F-2, compared to the control, cadmium content of liver decreased 25% in F-1, 28% in F-2 3150 decreased 22% md 25% in kidney. In femur, also decreased 53% in F-1 and 59% in F-2 respectively. The test of cadmium content in feces indicate that the content considerably increased within 1% level in both group F-1 and F-2, as compared to the control(42% in F-1, 54% in F-2). As shown the above results, have seen the removal effect of cadmium by polyphenol compound.

• Advances in environmental research
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• v.3 no.4
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• pp.283-292
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• 2014

Iron precipitating organisms play a significant role in the formation of ferric hydroxide precipitate, which acts as strong adsorbent for toxic metal. In this respect four different iron precipitating cultures were isolated from Hutti gold mine surface winze water sample on citrate agar medium. The best isolate was screened out for metal removal study on the basis of fast visual iron precipitation. The selected isolate was identified as Enterobacter sp. based on routine biochemical tests and Biolog GN microplate results and as Enterobacter cloacae subsp. dissolvens by 16S rRNA gene sequence analysis (GenBank accession number EU429448). Influence of medium composition, medium initial pH, the influence of inoculum size, effect of various media and ferric ammonium citrate concentration were studied on metal removal in shake flask experiments. Under the optimized conditions studied, E. cloacae showed $94{\pm}2$, $95{\pm}2$ and $70{\pm}2%$ of cadmium, copper and mercury removal from a simulated waste in shake flask studies. In lab scale column reactor more than 85% of copper and mercury removal was achieved.