Sung-Yong Cho

Adsorption of heavy metals by brewery biomass

In this work, biosorption of lead, copper and cadmium by waste brewery yeast has been studied. The adsorption capacity for lead, copper and cadmium on the biomass increased with the increasing temperature and the maximum uptakes were 0.465 mmolPb/g (96.4 mg/g), 0.769 mmolCu/g (48.9 mg/g) and 0.127 mmolCd/g (14.3 mg/g) at 308 K. The Langmuir isotherm, favorable type, and the pseudo second-order kinetic model represent our experimental data very well. The heat of biosorption was evaluated from the Langmuir isotherm equation, and the biosorption of lead, copper and cadmium was endothermic reaction.

Telomere length shortening in non-Hodgkin's lymphoma patients undergoing chemotherapy

We investigated telomere length changes in patients with non-Hodgkins lymphoma (NHL) receiving conventional-dose chemotherapy. Using Southern blot analysis, telomere length was measured in peripheral blood mononuclear cells from five NHL patients at diagnosis, 15 NHL patients after chemotherapy, and 39 healthy controls. Compared with age-matched putative normal controls, telomeres were significantly shorter in NHL patients at diagnosis. Mean telomere length was shorter after chemotherapy than before chemotherapy and was shorter after chemotherapy than in age-matched putative healthy controls. There was no correlation between the extent of telomere shortening and time elapsed after chemotherapy. These findings suggest that in NHL patients hematopoietic stem cells lose telomere length during the recovery period from bone marrow suppression after conventional-dose chemotherapy.

Removal of Heavy Metal-Cyanide Complexes by Ion Exchange

Simultaneous removal of heavy metal and cyanide ions in an ion exchange column is studied on the basis of formation of metal-cyanide complexes at high pH range. Strong base anion exchange resin beads were contacted with water containing heavy metal (Cu, Cd, Zn) and cyanide ions in semi-fluidized and fluidized beds. Compositions of the heavy metal-cyanide complexes formed for different heavy metal and cyanide concentrations are used to explain the ion exchange behavior. Ion exchange equilibrium data of this study were fitted well with the Langmuir isotherm. The ion exchange capacity of CNas metal complexes increased to about three times that of free cyanide due to higher selectivity of metal complexes on the anion exchange resin. The ion exchange efficiency of the three heavy metalcyanide systems decreases as the concentration ratio of cyanide and heavy metal increases. The regeneration rates of the regenerants used was in the order of NaSCN>NaCN>NaOH, and the regeneration rate of NaOH was substantially lower than other two.

Simultaneous removal of cyanide and copper ions in a semi-fluidized ion exchanger bed

Simultaneous removal of cyanide and copper ions from electroplating wastewater was studied in a liquid-solid semi-fluidized ion exchanger bed. The diameter and the height of column are 20 mm and 600 mm, respectively. Strong-base anion exchange resin particles (Dowex 1X8-50) were contacted with synthetic solutions containing copper and cyanide ions. Cyanide and copper ions in the solution were analyzed by a cyanide electrode and ICP (inductively coupled plasma), respectively. The ion exchange equilibrium data of Cu+ removed as cyanide-copper complexes on Dowex 1X8-50 at 25 ‡C can be fitted with the Langmuir equation. Early leakage of cyanide from experimental loading profile data results in not only lower selectivity of free cyanide but also different selectivities of CN-Cu complexes due to the size and the structure of complexes. The optimum molar ratio (Q) between cyanide and copper ions is about 3 to obtain a reasonable removal rate of cyanide in this experiment.

Adsorption and desorption characteristics of 2-methyl-4-chlorophenoxyacetic acid onto activated carbon

Adsorption and desorption characteristics of the 2-methyl-4-chlorophenoxyacetic acid (MCPA) from aqueous solution onto the activated carbon (GAC, F-400) were studied. Adsorption equilibrium capacities of the MCPA increased with decreasing pH and temperature of the solution. Adsorption equilibrium of the MCPA could be represented by the Sips equation. The internal diffusion coefficients were determined by comparing the experimental concentration decay curves with those predicted from surface diffusion model and pore diffusion model. The adsorption model based on the linear driving force approximation (LDFA) was used for simulating the adsorption behavior of the MCPA in a fixed bed. Over ninety five percent desorption of the MCPA could be obtained using distilled water.

Influence of haze pollution on water-soluble chemical species in PM 2.5 and size-resolved particles at an urban site during fall

To investigate the influence of haze on the chemical composition and formation processes of ambient aerosol particles, PM2.5 and size-segregated aerosol particles were collected daily during fall at an urban site of Gwangju, Korea. During the study period, the total concentration of secondary ionic species (SIS) contributed an average of 43.9% to the PM2.5, whereas the contribution of SIS to the PM2.5 during the haze period was 62.3%. The NO3- and SO42- concentrations in PM2.5 during the haze period were highly elevated, being 13.4 and 5.0 times higher than those during non-haze period, respectively. The PM, NO3-, SO42-, oxalate, water-soluble organic carbon (WSOC), and humic-like substances (HULIS) had tri-modal size distributions peaks at 0.32, 1.0, and 5.2μm during the non-haze and haze periods. However, during the non-haze period they exhibited dominant size distributions at the condensation mode peaking at 0.32μm, while on October 21 when the heaviest haze event occurred, they had predominant droplet mode size distributions peaking at 1.00μm. Moreover, strong correlations of WSOC and HULIS with SO42-, oxalate, and K+ at particle sizes of <1.8μm indicate that secondary processes and emissions from biomass burning could be responsible for WSOC and HULIS formations. It was found that the factors affecting haze formation could be the local stable synoptic conditions, including the weak surface winds and high surface pressures, the long-range transportation of haze from eastern China and upwind regions of the Korean peninsula, as well as the locally emitted and produced aerosol particles.

Nonmyeloablative stem cell transplantation following a cytoreductive autograft in patients with non-Hodgkin's lymphoma who relapse after autologous transplantation

Nonmyeloablative stem cell transplantation following a cytoreductive autograft in patients with non-Hodgkins lymphoma who relapse after autologous transplantation