Electro-enhanced phytoremediation system on the removal of trace metal concentration from contaminated water.

The combination of electro-enhanced and hydroponic phytoremediation hereinafter referred to as electro-enhanced phytoremediation (EP) system, has been employed for rapid removal of trace metal concentration of lead (II) from contaminated water using Kentucky bluegrass (Poa pratensis L.) as accumulator plant. In this study, for rapid assessment the effectiveness of two-dimensional (2D) electrode configuration in electro-enhanced system was evaluated by agar media for 48h period of time. Furthermore, these configurations were applied to enhance the EP system for 9d period of time. Also, a common agrochemical-urea as chaotropic agent to facilitate the healthy growth of plant in contaminated water was evaluated. The results showed that the accumulation of lead (II) concentration was higher in the plant roots (i.e. high bioaccumulation coefficient (BC) value) than in aerial parts of plant (i.e. low translocation factor (TF) value). Also, the accumulation of lead (II) concentration in plant was higher under the treated urea of EP system. The chlorophyll content, biomass accumulation productivity, and water content (i.e. dry weight-fresh weight (DW/FW) ratio) of plant either under the treated urea or untreated urea with high accumulation of lead (II) concentration revealed that the Kentucky bluegrass has able to hold out the plant stress.

Interpretation of the interaction between cesium ion and some clay minerals based on their structural features.

Cesium (Cs+) is known to have a strong interaction with various clay minerals; however, it is not interpreted from the structure of clay minerals and the adsorption isotherm. The adsorption interactions between Cs+ and hydrobiotite (H-Bio), biotite (Bio), vermiculite (Verm), and exfoliated vermiculite (E-Verm) were evaluated by analyzing adsorption isotherm, basal spacing, and adsorption/desorption experiments. The Cs+ adsorption of H-Bio and Verm fitted well to the Langmuir adsorption isotherm, while the Cs+ adsorption of Bio and E-Verm fitted well to the Freundlich adsorption isotherm. The basal spacing of H-Bio and Verm was approximately 1.4 nm, while Bio and E-Verm basal spacing was 1.0 nm. The adsorption experiment results for Cs+ under the coexistence of Ca2+ and K+ indicated that the contribution of the interlayer sites to Cs+ adsorption on H-Bio and Verm was 25-40%, while the contribution of the interlayer sites to that on Bio and E-Verm was almost 0%. The adsorption isotherms reflected this interlayer contribution to Cs+ adsorption, which was dependent on the basal spacing. Therefore, the basal spacing of clay minerals is one of the key structural properties controlling both the adsorption capacity and the adsorption mechanism of Cs+ in clay minerals.

Evaluation of Removal Behavior of Cesium in Contaminated Soil Based on Speciation Analysis.

The removal efficiency of Cs from contaminated soil depends on its chemical species bound with the soil components. Therefore, in this study, we observed the elution behavior of Cs based on speciation analysis in a Cs removal experiment conducted on contaminated soils. The treatment method was optimized using simulated contaminated soil and applied to actual contaminated soil on a large scale as well. The elution rate of Cs was approximately 50% or more in both actual and simulated contaminated soil using the optimized treatment method. From the obtained results, a robust treatment method using an eluting reagent and a magnetic adsorbent with low energy costs is proposed. Additionally, the usefulness of speciation analysis in decontamination studies was confirmed.

Enhancement Effect of Humic Acid on Removal of Lead from Soil by Electrokinetic Process.

The environmentally friendly electrokinetic process was investigated using model contaminated soil with Pb and humic acid. Although humic acid has a negative charge, it moved toward the cathode side by electroosmotic flow. The removal efficiency of Pb from model contaminated soil was 48.0% under 1 V/cm of the potential gradient after 72 h of operation, while it improved to 72.6% with humic acid. These results indicated that humic acid has high potential for application in the environmentally friendly remediation of soil.

Functionalization of Shirasu-balloons Surface for Removal of Cadmium Ions from Contaminated Soil.

Microspheres of aluminosilicate glass from volcanic sediment, whose surfaces were modified with functional groups, Shirasu-balloons (SB), were investigated as an adsorbent to remove cadmium ions from contaminated soil. The introduction of thiol groups (-SH) on the surface of SB enabled it to adsorb cadmium ions. Meanwhile, the introduction of an alkyl group (-ODS) made the surface of SB hydrophobic, and consequently increased the mechanical strength of SB. Those adsorbents could float up on the water surface after the adsorption process. The prepared adsorbent was characterized by FTIR spectrophotometry, elemental analysis and optical microscopy for making photographic images. The adsorption of cadmium ions on the adsorbent was investigated by comparing the results by a plain SB with those by thiol-functionalized SB. The adsorption maximum for cadmium ions was 3.75 mg/g for SH-SB and 2.62 mg/g for SH-ODS-SB, respectively. The adsorption of cadmium ions on functionalized SH-SB and SH-ODS-SB fitted well to the Langmuir isotherm equation. After a shaking time of 24 h, the recovering ratios of the absorbents from soil were 73 wt% for SH-SB and 98 wt% for SH-ODS-SB absorbents. In addition, the kinetic and adsorption-desorption properties of the adsorbent were also considered.

Development of Separation Technologies for Environmental Remediation.

This paper introduces some studies on the development of separation technologies for environmental remediation that have been performed in my laboratory over the past 20 years. The studies are related mainly to the development of easily collectable adsorbents and eco-friendly remediation technologies to remove pollutants from contaminated environments. First, the investigation of pollution in the Songhua River in China is described because it was that research that gave me the opportunity to consider the necessity of an easily collectable adsorbent. Then, the separation methods using the modified magnetite to remove pollutants by a magnet are introduced and the development of adsorbents that can float up to the water surface after adsorption at the bottom of the water is described. Electrochemical methods to accumulate pollutants in water on a carbon fiber electrode and electro-kinetic remediation to remove pollutants in soil are also introduced.

Humic acid induces the endothelial nitric oxide synthase phosphorylation at Ser1177 and Thr495 Via Hsp90α and Hsp90ß upregulation in human umbilical vein endothelial cells.

Humic acid (HA) has been implicated as a contributory factor for blackfoot disease, which is an endemic peripheral vascular disease. We investigated the effect of HA on the regulation of endothelial nitric oxide (NO) synthase (eNOS) in human umbilical vein endothelial cells (HUVECs) to evaluate the involvement of eNOS and related factors in peripheral vascular impairment with HA exposure. Treatment of HUVECs with HA induced upregulation of eNOS. This result coincides with those of previous studies. Furthermore this is the first study to report that HA induces upregulation of heat shock protein (Hsp)90α, Hsp90ß, eNOS phosphorylation at Ser1177, and eNOS phosphorylation at Thr495, as compared to that in the control. In contrast, treatment with BAPTA, an intracellular Ca(2+) chelator, inhibited upregulation of these proteins induced by HA. This study demonstrates that HA treatment leads to increases in both Hsp90α and Hsp90ß proteins and indicates that Hsp90α leads to eNOS phosphorylation at Ser1177 and that Hsp90ß leads to eNOS phosphorylation at Thr495, respectively. Upregulation of eNOS, Hsp90α, and Hsp90ß in HUVECs is regulated by intracellular Ca(2+) accumulation induced by HA. These results suggest that upregulation of eNOS phosphorylation at Ser1177 and eNOS phosphorylation at Thr495 produce NO and superoxide anions, respectively, resulting in generation of peroxynitrite, which causes impairment of vascular endothelial cells.

Effects of peat fires on the characteristics of humic acid extracted from peat soil in Central Kalimantan, Indonesia.

When peat forest fires happen, it leads to burn soil and also humic acids as a dominant organic matter contained in peat soil as well as the forest. The structure and properties of humic acids vary depending on their origin and environment, therefore the transformation of humic acid is also diverse. The impacts of the peat fires on peat soil from Central Kalimantan, Indonesia were investigated through the characterization of humic acids, extracted from soil in burnt and unburnt sites. The characterization of humic acids was performed by elemental composition, functional groups, molecular weight by HPSEC, pyrolysate compounds by pyrolysis-GC/MS, fluorescence spectrum by 3DEEM spectrofluorometer, and thermogravimetry. The elemental composition of each humic substance indicated that the value of H/C and O/C of humic acids from burnt sites were lower than that from unburnt sites. The molecular weight of humic acids from burnt sites was also lower than that from unburnt sites. Pyrolysate compounds of humic acids from unburnt sites differed from those of humic acids from burnt soil. The heating experiment showed that burning process caused the significant change in the properties of humic acids such as increasing the aromaticity and decreasing the molecular weight.

Coating of magnetite with mercapto modified rice hull ash silica in a one-pot process.

In this research, mercapto-silica coated magnetite (Fe3O4-SiO2-SH) has been prepared in aqueous solution through a simple approach so called a one-pot process. The Fe3O4-SiO2-SH was prepared in nitrogen condition by mixing magnetite, 3-mercaptopropyltrimethoxysilane (MPTMS), and sodium silicate (Na2SiO3) solution extracted from rice hull ash, and adjusting the pH of 7.0 using hydrochloric acid. The residue was washed with deionized water, dried at 150°C and separated with an external magnetic field. In that work, the volume of MPTMS and Na2SiO3 was varied and the total amount of Si represented as silica was kept constant. Characters of the material including the functional group presence, the structure, the porosity, the morphology and stability toward various solvents were identified and evaluated. Results of characterization indicated that mercapto-silica has been coated magnetite particle with a simple one-pot process. Coating mercapto-silica on magnetite increases particle size, surface area, and chemical stability. Additionally, Fe3O4-SiO2-SH also shows high stability toward various organic solvents. The magnetic property of magnetite does not change after coating and the addition of nonmagnetic material still gives high value of maximum saturation magnetization. The presence of mercapto groups effective for interaction with heavy metal ions, the high chemical stability without removing the magnetic property promises the prospective application of Fe3O4-SiO2-SH in the future such as for separation and removal of heavy metal ions from aquatic environments.

Agar-encapsulated adsorbent based on leaf of platanus sp. to adsorb cadmium ion in water.

A low cost and environmentally friendly adsorbent was developed based on leaf of platanus sp. to adsorb cadmium ion in water. The adsorbent was modified with citric acid and then also encapsulated in agar for easy separation after the adsorption process. Parameters such as adsorbent dose, stirring time, solution pH and modification of the adsorbent with citric acid were investigated in a batch experiment in order to determine the optimum condition for Cd (II) adsorption. Based on the Langmuir isotherm adsorption model, the adsorption capacity of cadmium ion for raw adsorbent, modified adsorbent with citric acid and encapsulated adsorbent were 3.69, 15.31 and 6.89 mg/g, respectively. The high adsorption capacity after treatment with citric acid may be due to the increase in carboxylic content of the adsorbent surface and also the increase of surface area and pore volume of the adsorbent. With this high adsorption capacity for cadmium ion and an abundance of raw materials, this bio-adsorbent could be considered as a low cost adsorbent in the near future.

Voltammetric detection of ovalbumin using a peptide labeled with an electroactive compound.

For this study, a new method was developed to electrochemically detect ovalbumin via its binding with the peptide-1(RNRCKGTDVQAW) in lysozymes. The peptide that exists at the C-terminal of a lysozyme was combined with ovalbumin. When an electroactive compound was introduced to the N-terminal side of the peptide through ethylene gycolbis(sulfosuccinimidyl succinate), the labeled peptide-1 served as a probe for the detection of ovalbumin. The electrode responses of labeled peptide-1 were measured after the labeled peptide-1 and ovalbumin were incubated in a 0.1 M phosphate buffer (pH 5.6). As a result, the electrode response decreased as the concentration of ovalbumin increased. The detection limit of ovalbumin was 2.3 × 10(-11) M as estimated at 3-fold the standard deviation (3σ) (n = 5). Because the steric structure of the peptide and some of the amino acid residues were related to the binding, we prepared a peptide-2, to which the N- and C-terminals of peptide-1 were alternated. The decrease in the response for the labeled peptide-2 was less than that for the labeled peptide-1. In addition, the peak current of a peptide-3, for which the D of peptide-1 was replaced with S, was hardly changed with or without ovalbumin. Therefore, it was clear that the binding was influenced by the steric factors and by the sequence of the peptide. However, a peptide-1 with bis(sulfosuccinimidyl) suberate was designed to investigate the hydrophobic influences on the probe. The change in the peak current was smaller than that of peptide-1 with ethylene gycolbis(sulfosuccinimidyl succinate), which was due to the hydrophobic properties of the alkyl chain between the peptide and the ovalbumin. The proposed method could be applied to the determination of ovalbumin in egg whites. Consequently, the concept becomes an electrochemical sensing method for proteins based on the protein-peptide interaction.

Mechanism of the toxicity induced by natural humic acid on human vascular endothelial cells.

Humic acid (HA), a group of high-molecular weight organic compounds characterized by an ability to bind heavy metals, is normally found in natural water. Although the impairment of vascular endothelial cells in the presence of humic substances has been reported to be involved in some diseases, the mechanisms responsible for this involvement remain unclear. In this study, we examined the cytotoxicity of HA obtained from peatland in Central Kalimantan, Indonesia, to human vascular endothelial cells, as well as the mechanisms behind these effects. It was found that 50 mg/L HA showed cytotoxicity, which we considered to be mediated by apoptosis through the mitochondrial pathway because of an increase in the expression of caspases 6 and 9 in response to HA administration. In addition, this cytotoxicity was enhanced when cells in this experimental system were exposed to oxidative stress, while it was decreased by the addition of vitamin C. Thus, we conclude that the apoptosis induced by HA depends upon oxidative stress. Furthermore, an iron chelator, DFO, showed a tendency to decrease HA-induced cytotoxicity, suggesting that iron may potentially mediate HA-induced oxidative stress. In conclusion, long-term consumption of HA-rich water obtained from our study area may cause damage to endothelial cells and subsequent chronic health problems.

Maternal-to-fetal transfer and concentration profiles of PCB congeners for Steller sea lions (Eumetopias jubatus) from Hokkaido, Japan.

The concentrations of PCB congeners in the blubber and liver of mother Steller sea lions (Eumetopias jubatus; SSLs) and their fetuses from the coast of Hokkaido, Japan in 2008, 2010 and 2012 were analyzed by HRGC-HRMS, in order to elucidate PCB congener profiles and maternal-to-fetal transfer of PCBs in SSLs. ΣPCBs in the fetuses were 1400 ± 660 (the mean ± SD) ng/g-fat in the blubber and 570 ± 320 ng/g-fat in the liver, respectively. There was a concern that SSLs had been contaminated by PCBs during the fetal period. The concentrations of the major congeners in the blubber and liver were a correlation between the fetus and mother (blubber: r=0.9934, liver: r=0.9160; P ≦ 0.05). The results indicated that PCBs in the fetuses came from the mothers. #177 and #199 showed no correlations between the fetus and the mother in the blubber and liver. This indicated a selective capture by some natural protector such as the placenta.

Concentration profiles of PCB congeners in the blubber and liver of Steller sea lions (Eumetopias jubatus) from the coast of Hokkaido, Japan.

The concentrations of PCB congeners in the blubber and liver of male and female Steller sea lions (Eumetopias jubatus; SSLs) collected from the Shakotan Peninsula and the Nemuro Strait, Hokkaido, Japan in 2008 and 2010 were measured by HRGC-HRMS, in order to express the concentration profiles in SSLs at these regions. #153 predominated in both organs, followed by #138, #99 and #118. In males, #28 and #31 were concentrated particularly in the blubber, while #177 and #199 were accumulated specifically in the liver. The differences in these concentration profiles might be expressed by the differences in the organs and their functions. The concentrations of #99, #118, #138, #153, and #180 in the blubber appeared to correspond significantly with the differences between genders. The details of the surveys on PCB congeners in SSLs could clarify the differences in the residue levels of individual congeners for organs and genders.

Metal concentrations of river water and sediments in West Java, Indonesia.

To determine the water environment and pollutants in West Java, the contents of metals and general water quality of the Ciliwung River in the Jakarta area were measured. High Escherichia coli number (116-149/mL) was detected downstream in the Ciliwung River. In addition to evaluate mercury pollution caused by gold mining, mercury contents of water and sediment samples from the Cikaniki River, and from paddy samples were determined. The water was not badly polluted. However, toxic metals such as mercury were detected at levels close to the baseline environmental standard of Indonesia (0.83-1.07 µg/g of sediments in the Cikaniki River). From analyses of the paddy samples (0.08 µg/g), it is considered that there is a health risk caused by mercury.

Adsorption behavior of some aromatic compounds on hydrophobic magnetite for magnetic separation.

In this study, a hydrophobic magnetite coated with an alkyl chain or a phenyl group on the surface was prepared and used as an adsorbent to investigate the adsorption behavior of aromatic compounds having various values of log P(ow) (phenol 1.46, benzonitrile 1.56, nitrobenzene 1.86, benzene 2.13, toluene 2.73, chlorobenzene 2.84 and o-dichlorobenzene 3.38) onto hydrophobic magnetite. The hydrophobic magnetites were modified with stearic acid and phenyltrimethoxysilane, and the modification amounts were 9.84 × 10(-3) and 4.17 × 10(-2)mmol/g, respectively. The aromatic compounds used in this study were divided into 3 groups depending on the log P(ow): 1

Direct detection of uric acid in body fluid samples by using boron doped graphite nano particles as the working electrode.

Boron doped graphite nano particles were used as functioning elements for creation of electrodes for the detection of uric acid in biological samples. The electrode obtained in this manner was capable of oxidizing ascorbic acid at lower potentials. This provided a desirable solution to the interfering problem encountered in the detection of uric acid in biological samples caused by ascorbic acid. The detectable concentrations for uric acid ranged from 5.0 to 130 µM. The applicability of the electrode was experimentally demonstrated by the successful direct detection of uric acid in real urine samples.

Determination of nitrobenzene in water and ice samples collected from the Songhua River after an explosion of a petrochemical plant and investigation on enclosing behavior of nitrobenzene into ice.

In this study, nitrobenzene in water and ice samples collected from the Songhua River after the explosion of a petrochemical plant was determined by GC/MS. The results showed that nitrobenzene was detected in most of the water and ice samples taken from the Songhua River. However, the concentration of nitrobenzene in all water and ice samples was from 0 to 0.65 microg L(-1); this range was sufficiently lower than the permissible level (0.017 mg L(-1)) for drinking water in China. The enclosing behavior of nitrobenzene in ice was also investigated. The amount of nitrobenzene enclosed in ice was lower than that reported by UNEP.

Nitrobenzene-adsorption capacity of carbon materials released during the combustion of woody biomass.

The present study investigated the adsorptive ability of carbon materials (C1 and C2) released during the combustion of woody biomass. The physical and chemical properties, adsorption dynamics and adsorption isotherms of the adsorbents were compared with those of commercially available carbon that was powdered and activated. The percent nitrobenzene adsorption from an aqueous solution (nitrobenzene: 50mg/L) after 3h of adsorption using C1 was 92% compared with 81% when using the activated carbon powder. The saturated adsorption amounts of nitrobenzene were 294 mg/g for C1 and 344 mg/g for the activated carbon powder. However, the adsorption equilibrium constant for C1 was approximately 7-fold greater than that of the activated carbon powder. The methylene blue-adsorption capacity of C1 was similar to nitrobenzene adsorption. Thus, the results of the present study confirm that the carbon material resulting from the combustion of woody biomass is an inexpensive and environmentally friendly adsorbent for nitrobenzene.

Selective elimination of lead(II) ions by alginate/polyurethane composite foams.

A new type of adsorbent which is capable of selectively adsorbing lead(II) ions (Pb(2+)) was developed. The adsorbent was generated by reaction of sodium alginate with NB-9000B, a polyisocyanate type of prepolymer of polyurethane. The adsorbent was a hydrophilic and flexible alginate/polyurethane composite foam (ALG/PUCF) with the alginate chemically immobilized in the cell walls of the foam. Acid-base titration was used to quantify the concentration of carboxyl groups, which are present on the alginate molecules of the ALG/PUCF, functioning as the essential sites for binding Pb(2+). For the optimized ALG/PUCF, the carboxyl was found to be 38.2+/-1.2mumol/g of dry weight. The capacity for adsorbing Pb(2+) ions in 1.0g of dry weight of the optimized ALG/PUCF was found to be 16.0+/-2.1mumol, indicating that ion exchange was the essential mechanism for adsorbing Pb(2+) ions. The adsorption capacity was found to be highly sensitive to the pH of the sample solution; lower pH (<3) significantly decreased the adsorption. Competing ions such as Mg(2+), Ca(2+), and Cd(2+) also caused a decrease in selectivity and capacity for Pb(2+) adsorption, although the effect was less pronounced than the effect of pH. The ALG/PUCF is highly stable, flexible and easy to use. ALG/PUCF is also reusable after regeneration with ethylenediamine-N,N,N',N'-tetraacetic acid, disodium salt (EDTA-2Na). Due to these features, this adsorbent may be highly useful for elimination of Pb(2+) ions from contaminated water.