• Journal of the Korea Institute of Building Construction
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• v.19 no.2
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• pp.139-147
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• 2019

In this study, an experiment was conducted to evaluate the properties of cement matrix using diatomite and silica gel as adsorbents of radon. The adsorption properties of diatomite of a natural adsorbent and silica gel of an artificial sorbent were examined to confirm the reduction of radon gas concentration of the removal of radon gas in the indoor environment of the human body. We conducted a performance evaluation for the study. The fluidity, air content, density, absorption, flexural failure load, thermal conductivity and radon gas concentration of the specimen using diatomite and silica gel were measured. the fluidity and the air content of the adsorbed matrix with diatomite were decreased as the diatomite replacement ratio increased. Which seems to affect the subsequent matrix by the absorption of the compounding water of diatomite. As the replacement rate of silica gel increased, the fluidity decreased and the air content increased up to constant replacement rate. It is judged that the surface of the silica gel has a critical point at which it can react with moisture.

• Membrane Journal
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• v.32 no.2
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• pp.100-108
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• 2022

Among various industries, the textile industry uses the largest amount of water for coloring textiles which leads to a large amount of wastewater containing various kinds of dye. There are various methods for the removal of dye such as flocculation, ozone treatment, adsorption, etc. But these processes are not much successful due to the issue of recycling which enhances the cost. Alternatively, the membrane separation process for the treatment of dye in wastewater is already documented as the best available technique. Polymeric membrane and ceramic membrane are two separate groups of separation membranes. Advantages of ceramic membranes include the ease of cleaning, long lifetime, good chemical and thermal resistance, and mechanical stability. Ceramic membranes can be prepared from various sources and natural materials like clay, zeolite, and fly ash are very cheap and easily available. In this review separation of wastewater is classified into mainly three groups: ultrafiltration (UF), microfiltration (MF), and nanofiltration (NF) process.

• Mass Spectrometry Letters
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• v.13 no.4
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• pp.166-176
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• 2022

Banana peels are also widely used as bio-adsorbent in the removal of chemicals contaminants and heavy metals from water and soil. GC-MS plays an essential role in the phytochemical analysis and chemo taxonomic studies of medicinal plants containing biologically active components. Intrinsically, with the use of the flame ionization detector and the electron capture detector which have very high sensitivities, Gas chromatography can quantitatively determine materials present at very low concentrations and most important application is in pollution studies. In the present study banana peels were used as bio-adsorbent to remediate the heavy metal contaminated water taken from three different stations located around the industrial belts of Ranipet, Tamilnadu, India. The AAS analysis of the samples shows a decrement of chromium concentration of 98.93%, 96.16% and 96.5% in Station 1, 2 and 3 respectively which proves the efficiency of the powdered peels of Musa paradisiaca. The GC-MS analysis of the control and treated peels of Musa paradisiaca reveals the presence of phytochemicals like Acetic Acid, 1-Methylethyl Ester, DL-Glyceraldehyde Dimer, N-Hexadecanoic Acid, 3-Decyn-2-Ol, 26-Hydroxy, Cholesterol, Ergost-25-Ene-3,5,6,12-Tetrol, (3.Beta.,5.Alpha.,6.Beta.,12.Beta.)-, 1-Methylene-2b-Hydroxymethyl-3, and 3-Dimethyl-4b-(3-Methylbut-2-Enyl)-Cyclohexane in the control banana peels. The banana peels which were used for the treatment reveals the changes and alteration of the phytochemicals. It is concluded that the alteration in phytochemicals of the experimental banana peels were due to adsorption of chromium heavy metal from the sample.

• Journal of Microbiology and Biotechnology
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• v.33 no.7
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• pp.895-908
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• 2023

Disposal of waste containing heavy metals into the environment is a major threat to human health and can result in toxic or chronic poisoning in aquatic life. In the current study, metal-resistant Raoultella ornithinolytica was isolated from metal-contaminated samples collected from the Tanjaro River, located southwest of Sulaymaniyah, Iraq. R. ornithinolytica was identified by partial amplification of 16S rRNA. The uptake potency of heavy metals was assessed using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and indicated that R. ornithinolytica removed 67, 89, 63.4, 55.6, 56.5, 65, and 61.9% of Cd, Pb, Cr, Ni, Zn, Co, and Fe, respectively. These removal rates were influenced by temperature, pH, and contact time; at 35℃ and pH 5 with a change in the incubation time, the reduction rate improved from 89 to 95% for Pb, from 36.4 to 45% for Cu, and from 55.6 to 64% for Ni. Gene analysis indicated that R. ornithinolytica contained pbrT, chrB, nccA, iroN, and czcA genes, but the pcoD gene was absent. Energy-dispersive X-ray spectroscopy (EDS) images showed evidence of metal ion binding on the cell wall surface with different rates of binding. Transmission electron microscopy (TEM) detected different mechanisms for metal particle localization; cell surface adsorption was the main mechanism for Pb, Zn, and Co uptake, while Cd, Ni, and Fe were accumulated inside the cell. The current study describes, for the first time, the isolation of R. ornithinolytica from metal-contaminated water, which can be used as an eco-friendly biological expedient for the remediation and detoxification of metals from contaminated environments.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1277-1284
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• 2005

Alkylphenol Polyethoxylate(APEs) and their metabolites were determined in the aquatic environment in the central Nakdong river basin. The concentrations of APE's ranged between $0.62{\sim}11.70\;{\mu}g/L$ from the Nakdong and the Kumho rivers, and were $70.00{\sim}212.50\;{\mu}g/L$ in the samples from the 3rd industrial complex stream and the Dalseo stream, which are both heavily polluted by industrial wastewater and domestic wastewater. The APEs revealed a removal rate of more than 87% by biodegradation and adsorption etc. in the wastewater treatment plant. Nonylphenol polyethoxylates(NPnEO) and Nonylphenol carboxylic acid(NPnEC) consisted of APE metabolites shifted from NP($n=4{\sim}10$)EO and NP($n=4{\sim}10$)EC to NP($n=1{\sim}3$)EO and NP($n=1{\sim}3$)EC or removed by the adsorption of activated sludge during the biological wastewater treatment process. Upper streams have a higher distributed rate of NP($n=7{\sim}10$)EO than water downstream. Continuous monitoring is necessary for non-point sources as well as point sources, such as a wastewater treatment plant. Effluent concentrations of nonylphenol(NP) in industrial wastewater and domestic wastewater averaged about 4.33 and $1.70\;{\mu}g/L$, respectively. In addition, the removal rate average was 90% in the wastewater treatment plant. NP concentrations in the rivers did not exceed $1.0\;{\mu}g/L$, which are prescribed by environmental risk concentration in the USA and Europe. However, NP required continuous monitoring, which detected over $0.1\;{\mu}g/L$ in all river areas.

• Journal of Applied Biological Chemistry
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• v.57 no.1
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• pp.65-72
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• 2014

Biochar (BC) from biomass pyrolysis is a carbonaceous material that has been used to remove various contaminants in the environment. The eliminatory action for burcucumber (Sicyos angulatus L.) as an invasive plant is being consistently carried out because of its harmfulness and ecosystem disturbance. In this study, burcucumber biomass was converted into BCs at different pyrolysis temperatures of 300 and $700^{\circ}C$ under a limited oxygen condition. Produced BCs were characterized and investigated to ensure its efficiency on antibiotics' removal in water. The adsorption experiment was performed using two different types of antibiotics, tetracycline (TC) and sulfamethazine (SMZ). For the BC pyrolyzed at a high temperature ($700^{\circ}C$), the values of pH, electrical conductivity, and the contents of ash and carbon increased whereas the yield, mobile matter, molar ratios of H/C and O/C, and functional groups decreased. Results showed that the efficiency of BCs on antibiotics' removal increased as pyrolysis temperature increased from 300 to $700^{\circ}C$ (38 to 99% for TC and 6 to 35% for SMZ). The reaction of ${\pi}-{\pi}$ EDA (electron-donor-acceptor) might be involved in antibiotics' adsorption to BCs. BC has potential to be a superior antibiotics' adsorbent with environmental benefit by recycling of waste/invasive biomass.

• Clean Technology
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• v.25 no.1
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• pp.91-97
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• 2019

Oxidative desulfurization (ODS) has received much attention in recent years because refractory sulfur compounds such as dibenzothiophenes can be oxidized selectively to their corresponding sulfoxides and sulfones, and these products can be removed by extraction and adsorption. In this work, The oxidative desulfurization of marine diesel fuel was performed in a batch reactor with hydrogen peroxide ($H_2O_2$) in the presence of various supported heteropoly acid catalysts. The catalysts were characterized by XRD, XRF, XPS and nitrogen adsorption isotherm techniques. Based on the sulfur removal efficiency of promising silica supported heteropoly acid catalysts, the ranking of catalytic activity was: $30\;H_3PW_{12}/SiO_2$ > $30\;H_3PMo_{12}/SiO_2$ > $30\;H_4SiW_{12}/SiO_2$, which appears to be related with their intrinsic acid strength. The $30\;H_3PW_{12}/SiO_2$ catalyst showed the highest initial sulfur removal efficiency of about 66% under reaction conditions of $30^{\circ}C$, $0.025g\;mL^{-1}$ (cat./oil), 1 h reaction time. However, through the recycle test of the $H_3PW_{12}/SiO_2$ catalyst, significant deactivation was observed, which was attributed to the elution of the active component $H_3PW_{12}$. By introducing cesium cation ($Cs^+$) into the $H_3PW_{12}/SiO_2$ catalyst, the stability of the catalyst was improved with changing the solubility, and the $Cs^+$ ion exchanged catalyst could be recycled for at least five times without severe elution.

• Journal of the Mineralogical Society of Korea
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• v.16 no.4
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• pp.283-293
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• 2003

Domestic water treatment plants operate the rapid and slow filtering system using the filtering sands. Most of them are composed of beach sands, which have less sorption capacity of heavy metals as well as organic contaminants. Therefore, the development of fortified functional filtering materials with high removal capacity of organic and inorganic contaminants is needed to prevent the unexpected load of contaminated source water. This study aims to test the hydrochemical change and the removing capacity of heavy metals such as Cd, Cu, and Pb on the Jumunjin sand, feldspathic sand(weathering product of Jecheon granite), feldspathic mixing sand I(feldspathic sand mixed with 10 wt% zeolite), and feldspathic mixing sand II (feldspathic sand mixed with 20 wt% zeolite). Feldspathic mixing sand I and II showed the eruption of higher amounts of cations and anions compared with the Jumunjin sand and feldspathic sand. They also showed higher eruption of Si, Ca, $SO_4$ ions than that of Al, $NO_3$, Fe, K, Mg, and P. Feldspathic mixing sand II caused higher eruption of some cations of Na, Ca, Al than feldspathic mixing sud I, which is the result controlled by the dissolution of zeolite. Jumunjin sand and feldspathic sand showed very weak sorption of Cd, Cu and Pb. In contrast to this, feldspathic mixing sand I and II showed the high sorption and removal capacity of the increasing order of Cd, Cu and Pb. Feldspathic mixing sand II including 20% zeolite showed a fortified removal capacity of some heavy metals. Therefore, feldspathic mixing sand mixed with some contents of zeolite could be used as the fortified filtering materials for the water filtering and purification in the domestic water treatment plants.

• Clean Technology
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• v.28 no.1
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• pp.38-45
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• 2022

CuCl₂-loaded V₂O₅-WO₃/TiO₂ catalyst showed excellent activity in the catalytic oxidation of elemental mercury to oxidized mercury even under SCR condition in the presence of NH₃, which is well known to significantly inhibit the oxidation activity of elemental mercury by HCl. Moreover, it was confirmed that, when SO₂ was present in the reaction gas together with HCl, excellent elemental mercury oxidation activity was maintained even though CuCl₂ supported on the catalyst surface was converted to CuSO₄. This is thought to be because not only HCl but also the SO₄ component generated on the catalyst surface promotes the oxidation of elemental mercury. However, in the presence of SO₂, the total mercury balance before and after the catalytic reaction was not matched, especially as the concentration of SO₂ increased. In order to understand the cause of this, further studies are needed to investigate the effect of SO₂ in the SnCl₂ aqueous solution employed for mercury species analysis and the effect of sulfate ions generated on elemental mercury oxidation. It was confirmed that SO₂ also promotes NO_x removal activity, which is thought to be because the increase in acid sites by SO₄ generated on the catalyst surface by SO₂ facilitates NH₃ adsorption. The composition change and structure of the components present on the catalyst surface under various reaction conditions were measured by XRD and XRF. These measurement results were presented as a rational explanation for the results that SO₂ enhances the oxidation activity of elemental mercury and the NO_x removal activity in this catalyst system.

• Journal of Soil and Groundwater Environment
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• v.13 no.2
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• pp.1-11
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• 2008

Phenanthrene uptake by surfactant sorbed on activated carbon was investigated to recycle of surfactant in washed solution for contaminated soil. The partitioning of phenanthrene to the activated carbon coating with Triton X-100 as a surfactant was also evaluated by a mathematical model. Phenanthrene-contaminated soil (200 mg/kg) was washed in 10 g/L of surfactant solution. Washed phenanthrene in solution was separated by various particle loadings of granular activated carbon through a mode of selective adsorption. Removal of phenanthrene was 99.3%, and surfactant recovery was 88.9% by 2.5 g/L of granular activated carbon, respectively. Phenanthrene uptake by activated carbon was greater than that of phenanthrene calculated by a standard model for a system with one partitioning component. This is accounted for enhanced surface solubilization by hemi-micelles adsorbed onto granular activated carbon. The effectiveness factor is greater than 1 and molar ratio of solubilization to sorbed surfactant is higher than that of liquid surfactant. Results suggest that separation of contaminants and surfactants by activated carbon through washing process in soil is much effective than that of calculated in a theoretical model.