Im-Soon Kim

Preparation and characterization of porous reduced graphene oxide based inverse spinel nickel ferrite nanocomposite for adsorption removal of radionuclides

For the removal of uranium(VI) (U(VI)) and thorium(IV) (Th(IV)), graphene oxide based inverse spinel nickel ferrite (GONF) nanocomposite and reduced graphene oxide based inverse spinel nickel ferrite (rGONF) nanocomposite were prepared by co-precipitation of GO with nickel and iron salts in one pot. The spectral characterization analyses revealed that GONF and rGONF have a porous surface morphology with an average particle size of 41.41nm and 32.16nm, respectively. The magnetic property measurement system (MPMS) studies confirmed the formation of ferromagnetic GONF and superparamagnetic rGONF. The adsorption kinetics studies found that the pseudo-second-order kinetics was well tune to the U(VI) and Th(IV) adsorption. The results of adsorption isotherms showed that the adsorption of U(VI) and Th(IV) were due to the monolayer on homogeneous surface of the GONF and rGONF. The adsorptions of both U(VI) and Th(IV) were increased with increasing system temperature from 293 to 333±2K. The thermodynamic studies reveal that the U(VI) and Th(IV) adsorption onto GONF and rGONF was endothermic. GONF and rGONF, which could be separated by external magnetic field, were recycled and re-used for up to five cycles without any significant loss of adsorption capacity.

Porous graphene oxide based inverse spinel nickel ferrite nanocomposites for the enhanced adsorption removal of arsenic

Porous graphene oxide based magnetic inverse spinel nickel ferrite nanocomposites, namely graphene oxide based inverse spinel nickel ferrite (GONF) and reduced graphene oxide based inverse spinel nickel ferrite (rGONF), with particle sizes of around 30 to 40 nm were prepared by the co-precipitation of graphene oxide (GO) with nickel and iron salts in one pot. GONF and rGONF, having ferromagnetic and superparamagnetic properties respectively, were separated easily within 10 seconds, using a small external magnetic field. These nanocomposites were used for the adsorption removal of As(III) and As(V). Compared to bare nickel ferrite, other nanocomposites and GO, the nanocomposites show a high adsorption capacity for As(III) and As(V), with considerable enhancement. The enhanced high adsorption capacity is due to the increased number of pores and adsorption sites with increasing surface area in the GONF and rGONF composites, through reducing the aggregation of bare ferrites. The adsorption results found that more than 99.9% arsenic removal was achieved with the present nanocomposites. Since the nanocomposites show good stability without loss of their adsorption capacity for up to 5 cycles, they can be used for the practical removal of arsenic from water.

Iron Oxide Impregnated Morus alba L. Fruit Peel for Biosorption of Co(II): Biosorption Properties and Mechanism

Biosorption is an ecofriendly wastewater treatment technique with high efficiency and low operating cost involving simple process for the removal of heavy metal ions from aqueous solution. In the present investigation, Morus alba L. fruit peel powder (MAFP) and iron oxide impregnated Morus alba L. fruit peel powder (IO-MAFP) were prepared and used for treating Co(II) contaminated aqueous solutions. Further the materials were characterized by using FTIR and SEM-EDX analysis. From FT-IR analysis it was found that hydroxyl, methoxy, and carbonyl groups are responsible for Co(II) biosorption. The kinetic data obtained for both biosorbents was well fitted with pseudo-second-order kinetic model. The equilibrium data was in tune with the Langmuir and Freundlich isotherm models. The thermodynamic studies were also carried and it was observed that sorption process was endothermic at 298–328 K. These studies demonstrated that both biosorbents were promising, efficient, economic, and biodegradable sorbents.

Development plan of health impact assessments in Korea

AbstractAs the importance of health rises in the public consciousness, environmental health impact assessments (HIA) are gaining renewed attention. This implies that the existing medium-centered environmental assessments (EA) should shift toward recipient-centered EAs. Currently, sanitation and public health are health components of the environmental impact assessment (EIA) in Korea, which contain occupational and residential health, analysis of and mitigation measures against disease-causing factors (such as communicable diseases), and placement and management plans for public health facilities. In short, HIAs are managed under the sanitation and public health criteria of the EIA. This research is a comprehensive analysis of the most recent literature and online information regarding Korea’s EIA system, and has been undertaken in an effort to explore and suggest improvement measures for the nation’s HIA. An HIA’s definition, role, and international trends were reviewed, and building on those findings, a thorough examination explored means to effectively integrate the sanitation and public health component recommended by current regulations into the HIA (such as the EIA reporting guidelines). 1)Despite the current emphasis on health, the health component of the EIA is still insufficient. Comprehensive and effective improvement is required to secure its efficacy.2)The EIA concerns specific projects or developments, whereas the Strategic Environment Assessment (SEA) addresses policies, plans, and programs. On the other hand, the HIA targets both. In addition, the HIA, EIA, and SEA share significant commonalities, which render integration of HIA more feasible.3)The Ministry of Environment and the Ministry of Health and Welfare must cultivate a system of cooperation and share results of physical exams.4)The HIA should be incorporated into all plans and development projects. In addition, institutional measures must be put in place to promote the participation of local parties and healthcare researchers.5)The scope of sanitation and public health components in the EIA must be expanded for practical information to be reflected.6)Curriculum support must be provided for HIA education. In addition, support and consideration at the government level must occur for continuous research in the field.

Recent toxicological investigations of metal or metal oxide nanoparticles in mammalian models in vitro and in vivo: DNA damaging potential, and relevant physicochemical characteristics

Concomitant with the increase in production and application of various nanomaterials, researches on their cytotoxic and genotoxic potential have become well established, as exposure to these nanoscaled materials may contribute to detrimental health effects. Positive indications of the damaging effects of nanoparticles on DNA are likely to be inconsistent in in vitro systems, and thus the implementation of in vivo investigations has been achieved. This review summarizes the current results, both in vitro and in vivo, of the genotoxic effects of potential metal or metal oxide nanoparticles, including the oxides of aluminium, iron, silica, titanium, and zinc, as well as silver, gold, cobalt, quantum dots, and so forth. They present indications of different types of DNA damage, ranging from chromosomal aberrations, through DNA strand breaks, oxidative DNA damage, to mutations. Their toxicological profiles are definitely associated with physicochemical characters, depending upon the characterization methods by which they are analyzed, in particular, microscopy techniques. Besides physicochemical properties, we also discuss significant parameters that may influence genotoxic response, including toxicity assays/endpoint tests, exposure duration and route of exposure, and experimental conditions. We describe advantages and disadvantages of particular characterization methods, as well as the appropriateness of methodologies for investigating physicochemical characters. Therefore, recommendations on particle characterization are further emphasized, to provide better understanding of genotoxic potential.

The relationship between formaldehyde exposure levels and environmental diseases within residential environments

The present study aimed to find indicators to improve indoor air quality by measuring and evaluating formaldehyde in residential environments and analyzing household living patterns to determine whether residents suffer from environmental diseases. The average household concentration was 30.7 µg/m3. The average concentration in remodeled households was 38.8 µg/m3, which was higher than in households that had not been remodeled. Formaldehyde concentrations were higher in households residing at ground level than those in households based in underground spaces. The average concentration of households that had moved into their homes within the previous year were the highest at 43.5 µg/m3 with the concentrations gradually decreasing over time after move-in. Formaldehyde concentrations were higher in households that conducted ventilation 2-3 times per weekly (43.9 µg/m3) than those that conducted ventilation daily (26.1 µg/m3). The average concentration of the households that had experienced atopy was higher (36.7 µg/m3) compared to the households that had not (26.4 µg/m3).