• Membrane and Water Treatment
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• v.6 no.5
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• pp.393-409
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• 2015

Zinc and lead pollution are public environmental issues that have attracted lots of attention for a long time. Landfill leachate contains heavy metals, such as Zn(II) and Pb(II), which are usually related to the pollution of groundwater, especially in developing countries. Bentonite has been proven to be effective in enhancing the membrane property of clay, by which landfill liners can have better barrier performance towards the migration of contaminants. In this study, 5% sodium bentonite amended with locally available Fukakusa clay was utilized to evaluate the membrane behavior towards the heavy metals zinc and lead. The chemico-osmotic efficiency coefficient, ${\omega}$, was obtained through Zn(II) and Pb(II) solutions with different concentrations of 0.5, 1, 5, 10, and 50 mM. According to the results, ${\omega}$ continually decreased as the Zn(II) and Pb(II) concentrations increased, which is consistent with the Gouy-Chapman theory. Compared to normal inorganic ions, the membrane behavior towards heavy metal ions was lower. The migration of heavy metal ions was not observed based on experimental results, which can be attributed to the adsorption or ion exchange reaction. The mechanisms of the membrane performance change were discussed with the assistance of XRD patterns, free swelling results, XRF results, and SEM images.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.406-414
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• 2010

A novel polyacrylamide grafted hydrous ferric oxide adsorbent composite has been synthesized by using glow discharge electrolysis plasma. To optimize the synthesis conditions, the following parameters were examined in detail: applied power, discharge time, post polymerization temperature, post polymerization time, amount of crosslinking agent and hydrous ferric oxide gel added and so on. The adsorbent was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The removal percentage of the adsorbent in Pb(II) solution was examined and the data obtained showed that the adsorbent composite has a high capacity for lead ion. For the use in wastewater treatment, the thermodynamic and kinetic of Pb(II)-capture were also studied. Results indicated that the adsorption reaction was a spontaneous and an endothermic process, and it seems to be obeyed a pseudo-secondorder rate model. Moreover, the adsorption isotherm of Pb(II)-capture is following the Langmuir and Freundlich isotherm models.

• Journal of the Korean GEO-environmental Society
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• v.15 no.8
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• pp.39-44
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• 2014

Effects of operating parameters on the breakthrough properties of Pb(II) by $Mn_3O_4$ coated activated carbon prepared by supercritical technique were investigated through fixed-bed column experiments. The mass transfer zone and equilibrium adsorption capacity were enhanced about 2.8 times for Pb(II) by $Mn_3O_4$ coating onto activated carbon. Increase of bed height enhanced the residence time of Pb(II) in adsorption zone, giving the higher breakthrough time, mass transfer zone and equilibrium adsorption capacity. Increase of flow rate reduced the residence time and diffusion of Pb(II) in adsorption zone, therefore decreased the equilibrium adsorption capacity. The higher inlet concentration of Pb(II) decreased the breakthrough time and mass transfer zone through the promotion of Pb(II) transfer onto adsorbent.

• Journal of the Korean Wood Science and Technology
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• v.42 no.4
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• pp.450-459
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• 2014

Crushed pinewood and oakwood were studied as an adsorbent for Pb(II) removal from aqueous solution. Batch adsorption experiments were carried out to describe the effects of contact time, initial Pb(II) concentration, pH, competing cations, and adsorbent dosage on the Pb(II) adsorption process. Kinetic studies revealed that the Pb(II) adsorption process for pinewood and oakwood followed both pseudo first and pseudo second order model. The Fruendlich model best described equilibrium adsorption data with correlation coefficients ($R^2$) of 0.956 and 0.950 for pinewood and oakwood. The maximum adsorption capacity of Pb(II) onto pinewood and oakwood was found to be 16.853 and 27.989 mg/g, respectively. The Pb(II) adsorption onto both pinewood and oakwood was increased as pH increased in the pH range 3-9. The presence of cations such as $Na^+$, $Ca^{2+}$, and $Al^{3+}$ decreased Pb(II) adsorption. The Pb(II) removal was greater in seawater than deionized water, resulting from the presence of $CO{_3}^{2-}$ and $OH^-$ ions in seawater. This study showed that pinewood and oakwood have a potential application in the remediation of Pb(II) contaminated water.

• Korean Chemical Engineering Research
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• v.58 no.2
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• pp.301-306
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• 2020

We investigated the individual biosorption removal of lead, copper, and nickel ions from aqueous solutions using Chara sp. algae powder in a batch mode. The impact of several parameters, such as initial concentration of the metal ions, contacting time, sorbent dose, and pH on the removal efficiency, was investigated. The maximum removal efficiency at optimum conditions was found to be 98% for Pb(II) at pH = 4, 90% for Cu(II) at pH = 5, and 80% for Ni(II) at pH = 5. The isotherm study was done under the optimum conditions for each metal by applying the experimental results onto the well-known Freundlich and Langmuir models. The results show that the Langmuir is better in describing the isotherm adsorption of Pb(II) and Ni(II), while the Freundlich is a better fit in the case of Cu(II). Similarly, a kinetic study was performed by using the pseudo-first and second-order equations. Our results show that the pseudo-second-order is better in representing the kinetic adsorption of the three metal ions.

• Journal of the Korean Chemical Society
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• v.48 no.6
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• pp.590-598
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• 2004

The preconcentration and determination of trace Cu(II) and Pb(II) on calcium alginate beads in aqueous solution were studied. A calcium alginate beads were prepared by adding an alginic acid to sample solution contained Ca(II). Some following conditions were optimized: the pH of sample solution, amount of alginic acid, and stirring time for effective adsorption; the type and concentration of acid, and sonication time in an ultrasonic vibrator for the perfect de-sorption. A sample solution was prepared with Cu(II) and Pb(II) in DI water. And Ca(II) and ethanol was added into the sample solution. The pH of the final sample solution was controlled with buffer solution. The alginic acid were dispersed in the sample solution by a magnetic stirrer. This mixture was stored in room temperature for 30 min to form a calcium alginate. After the beads were filtered and washed on a membrane filter, the analytes were redissolved from the beads by an ultrasonic vibration of 10 minutes in 1.0M $HNO_3$ solution. The effect of diverse ions on the adsorption of analytes were studied. This procedure was applied for the analysis of two real samples. The recoveries in spiked samples were $90.4{\sim}104.3%$ for analytes.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3391-3398
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• 2013

The carboxylated multiwall carbon nanotubes (MWCNT-COOH) and functionalized with isatin derivative (MWCNT-isatin) have been used as efficient adsorbents for the removal of lead (Pb) from aqueous solutions. The influence of variables including pH, concentration of the lead, amount of adsorbents and contact time was investigated by the batch method. The adsorption of the lead ions from aqueous solution by modified MWCNTs was studied kinetically using different kinetic models. The kinetic data were fitted with pseudo-first-order, pseudo-second-order, and intra-particle diffusion models. The sorption process with MWCNT-COOH and MWCNT-isatin was well described by pseudo-second-order and pseudo-first-order kinetics, respectively which it was agreed well with the experimental data. Also, it involved the particle-diffusion mechanism. The values of regression coefficient of various adsorption isotherm models like Langmuir, Freundlich and Tempkin to obtain the characteristic parameters of each model have been carried out. The Langmuir isotherm was found to best represent the measured sorption data for both adsorbent.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.2
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• pp.33-41
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• 2018

Large amounts of leaves from street trees fall onto the streets annually and need to be cleaned and treated. Cherry trees are common street trees in Korea. The adsorption characteristics of Pb(II) by cherry leaf (CL) and cherry leaf-derived biochar (CB) were studied through a series of batch experiments. CB was produced through the carbonization of CL at $800^{\circ}C$ for 90 min. Carbonization increased the C content and pH value, while decreased H and O contents. Well developed pore structure was observed at the surface of CB. The pseudo-second order model better described the kinetics of Pb(II) adsorption onto CL and CB, indicating that the rate-limiting step of the heavy metal sorption is chemical sorption. Fast adsorption rates and high adsorption capacities were obtained by the carbonization from CL to CB. Langmuir models better adequately described the Pb(II) adsorption onto CL and CB. Maximum adsorption capacities of Pb(II) expressed by Langmuir constant, $Q^0$ were 37.31 mg/g and 94.34 mg/g, when CL and CB were used as adsorbents, respectively.

• Journal of environmental and Sanitary engineering
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• v.14 no.3
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• pp.80-89
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• 1999

The ion exchange resins have been synthesized from chlormethyl styrene-1,4-divinyl benzene(DVB) with 1%, 5%, and 10%-crosslinking and macrocyclic ligand of cryptand type by copolymerization method and the adsorption characteristics of uranium(VI), lead(II) and holmium(III) ions have been investigated in various experimental conditions. The correlation between the adsorption characteristics of rare earths and transition metal on the resins and stability constants of complexes with macrocyclic ligand have been examined. The $UO_2^{2+}$ aqueous solutions are not adsorbed on the resins below pH 3.0, but the power of adsorption of $UO_2^{2+}$ increased rapidly above pH 4.0. The adsorption power was in the order of 1%, 10%, and 5%-crosslinked resin, but adsorptive characteristics of resins decreased in proportion to the order of dielectric constants of solvents.

• Biotechnology and Bioprocess Engineering:BBE
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• v.2 no.2
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• pp.132-135
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• 1997

We prepared capsules containing Saccharomyces cerevisiae and Zoogloea ramigera cells for the removal of lead(II) and cadmium ions. Microbial cells were encapsulated and cultured in the growth medium. The S.cerevisiae cells grown in the capule did not leak through the capsule membrane. The dried cell density reached to 250 g/l on the basis of the inner volume of the 2.0 mm diameter capsule after 36 hour cultivation. The dry whole cell expolymer density of encapsulated Z.ramigera reached to 200 g/L. The capsule was crosslinked with triethylene tetramine and glutaric dialdehyde solutions. The cadmium uptake of encapsulated whole cell expolymer of Z.ramigera was 55mg Cd/g biosorbent. The adsorption line followed well Langmuir isotherm. The lead uptake of the encapsulated S. cerevisiae was about 30 mg Pb/g biomass. The optimum pH of the lead uptake using encapsulated S. cerevisiae was found to be 6. Freundlich model showed a little better fit to the adsorption data than Langmuir model 95 percent of the lead adsorbed on the encapsulated biosorbents was desorbed by the 1 M HCl solution. The capsule was reused 50 batches without loosing the metal uptake capacity. And the mechanical strength of the crosslinked capsule was retained after 50 trials.