• Journal of Korean Society of Water and Wastewater
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• v.14 no.1
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• pp.54-61
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• 2000

Recently, our circumstances are threatened by an accident that leakage of under ground storage tank and illegal dumping of synthetic organic compounds at chemical plants and many treatment methods, Activated carbon adsorption, Ozonization, Membrane filtration and Photocatalystic oxidation, are developed to remove such a synthetic organic compounds. And it has reported that Activated carbon adsorption have a great removal efficiency to nondegradable matters and organic compounds which have a high molecular weight. Comparing with other adsorbents, Activated carbon adsorption have a worse efficiency when ad desorption speed is low. Thus improved type of adsorbents was invented and one of those is Activated Carbon Filter. The purpose of this study was getting information about adsorption characteristic phenol which can be applied Activated Carbon Fiber and Granular Activated Carbon. In detail, With comparing removal characteristics of phenol in the presence Humic Acid using Activated Carbon Fiber(ACF) and Granular Activated. Carbon(GAC), it is to certify an effective application of Activated Carbon Fiber. At the range of this study, Batch test, Isotherm adsorption test and Factorial analysis, following conclusion were obtained from the results of this study. Batch test was carried to know time of adsorption equilibrium. In this study about time of adsorption equilibrium by ACF was faster than GAC's, for developed micropore of ACF. From the result of phenol adsorption test, High removal rate of adsorption is shown at pH 5. The result of lsotherm adsorption test, it has represented that the Freundlich's isotherm is most suitable one in others, that a ACF's adsorption capacity is more excellent than GAC's. Adsorption of phenol exiting humic acid is decreased getting raised humic acid concentration. Since ACF's micropore is developed at this time, an effect of high molecular humic acid is lower. Factorial analysis was carried to know about Main effect which was injection dosage of adsorbent in the range of this study.

• Membrane and Water Treatment
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• v.11 no.1
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• pp.59-68
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• 2020

The study objective was to evaluate the enhanced removal of high concentrations of phosphorus from synthetic wastewater (solely phosphorus-containing) and real wastewater (pig manure) by using carbon nanotube (CNT)-coated steel slag. Generally, phosphorus removal by steel slag is attributed to Ca²⁺ eluted from the slag. However, in this study, CNT was used to control the excess release of Ca²⁺ from steel slag and increase the phosphorus removal. The phosphorus removal rate by the uncoated steel slag was lower than that of the CNT-coated steel slag, even though the Ca²⁺ concentrations were higher in the solution containing the uncoated steel slag. Therefore, the phosphorus removal could be attributed to both precipitation with Ca²⁺ eluted from steel slag in aqueous solution and adsorption onto the surface of the CNT-coated steel slag. Furthermore, the protons released from the CNT surface by exchanging with divalent cations acted to reduce the pH increase of the solution, which is attributed to the OH^- eluted from the steel slag. The adsorption isotherm and kinetics of the CNT-coated steel slags followed the Freundlich isotherm and pseudo-second-order model, respectively. The maximum adsorption capacity of the uncoated and CNT-coated steel slags was 6.127 and 9.268 mg P g^-1 slag, respectively. In addition, phosphorus from pig manure was more effectively removed by the CNT-coated steel slag than by the uncoated slag. Over 24 hours, the PO₄-P removal in pig manure was 12.3% higher by the CNT-coated slag. This CNT-coated steel slag can be used to remove both phosphorus and metals and has potential applications in high phosphorus-containing wastewater like pig manure.

• Advances in environmental research
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• v.7 no.1
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• pp.53-71
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• 2018

Waste glass disposal causes environmental problems in the cities. To find a suitable green environmental solution for this problem low cost adsorbent in this study was prepared from waste glass. An effective new green adsorbent was synthesized by hydrothermal treatment of waste glass (WG), followed by acidic activation of its surface by HCl (WGP). The prepared adsorbent was characterized by scanning electron microscopy (SEM), X-ray fluorescence (XRF), X-ray diffraction (XRD), and BET surface measurement. The developed adsorbent was used for the removal of heavy metals (Cd, Cu, Fe, Pb and Zn) from well water. Batch experiments were conducted to test the ability of the prepared adsorbent for the removal of Cd, Cu, Fe, Pb and Zn from well water. The experiments of the heavy metals adsorption by adsorbent (WGP) were performed at different metal ion concentrations, solution pH, adsorbent dosage and contact time. The Langmuir and Freundlich adsorption isotherms and kinetic models were used to verify the adsorption performance. The results indicated high removal efficiencies (99-100%) for all the studied heavy metals at pH 7 at constant contact time of 2 h. The data obtained from adsorption isotherms of metal ions at different time fitted well to linear form of the Langmuir sorption equation, and pseudo-second-order kinetic model. Application of the resulted conditions on well water demonstrated that the modified waste glass adsorbent successfully adsorbed heavy metals (Cd, Cu, Fe, Pb and Zn) from well water.

• Environmental Engineering Research
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• v.16 no.2
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• pp.55-60
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• 2011

The removal of hexavalent chromium from aqueous solutions onto modified holly sawdust was studied at varying initial hexavalent chromium concentrations, adsorbent doses, pHs and contact times. The removal of hexavalent chromium from aqueous solutions increased with increasing adsorbent dosage and contact time. The percentage of hexavalent chromium removed from the aqueous solutions decreased with increasing hexavalent chromium concentration and pH of the solution. The kinetics of the adsorption of hexavalent chromium onto modified holly sawdust was analyzed using pseudo first-order and pseudo second-order models. The pseudo second-order model described the kinetics of adsorption of hexavalent chromium. The Langmuir and Freundlich isotherm models were used for modeling of the adsorption equilibrium data. The Langmuir isotherm model well described the equilibrium data for the removal of hexavalent chromium by modified holly sawdust. The obtained maximum adsorption capacity was 18.86 mg/g at pH 7. The results showed that modified holly sawdust can be used as a low cost adsorbent for the treatment of aqueous solutions containing chromium.

• Journal of Korean Society on Water Environment
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• v.23 no.1
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• pp.155-160
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• 2007

Constructed wetland has been widely used for the treatment of sewage, stormwater runoff, industrial wastewater, agricultural runoff, acid mine drainage and landfill leachate. For the removal of nitrogen and phosphorus, uptake by plants and adsorption to media material are the major processes, and, therefore, the selection of media with specific adsorption capacity is the critical factor for the optimal design of wetland along with the selection of appropriate plant species. In this study, two media materials (loess bead and mixed media) possessing different adsorption characteristics for ammonium and phosphate were selected, and their adsorption characteristics were evaluated. In addition, the performance of subsurface-flow wetland systems employing these media was evaluated in both batch and continuous flow systems. With LB medium, beter phosphorus removal was observed, while better ammonia removal was obtained with MM medium. In addition, enhanced removal efficiencies were observed in the wetland systems employing both media and aquatic plants, mainly due to the better environment for microbial growth. As a result, appropriate selection or combination of media with respect to the inflow water quality maybe important factors for the successful design and operation of wetland systems.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.3
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• pp.35-40
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• 2013

The present study was conducted to investigate the adsorption potential of red mud for fluoride removal. Different operation parameters such as the effect of contact time, initial concentration, pH, competing anions, seawater, adsorbent dose amount, and adsorbent mixture were studied. Nearly 3 hr was required to reach sorption equilibrium. Equilibrium sorption data were described well by Langmuir model and the maximum adsorption capacity of red mud was 5.28 mg/g. The fluoride adsorption at pH 3 was higher than in the pH range 5-9. The presence of anions such as sulfate, nitrate, phosphate, and bicarbonate had no significant effect on fluoride adsorption onto red mud. The fluoride removal by red mud was greater in seawater than deionized water, resulting from the presence of calcium and magnesium ion in seawater. The use of red mud alone was more effective for the removal of fluoride than mixing red mud with other industrial waste such as oyster shells, lime stone, and steel slag. This study showed that red mud has a potential application in the remediation of fluoride contaminated soil and groundwater.

• Advances in environmental research
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• v.4 no.1
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• pp.49-68
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• 2015

Chemically activated and carbonized adsorbents were prepared from Moringa oleifera pod husks (MOP), characterized and evaluated for their ability to remove a common antibiotic - ofloxacin (OFX) from aqueous solution. The pulverized precursor was steeped in a saturated ammonium chloride solution for a day to give the chemically activated adsorbent (AMOP). A portion of AMOP was pyrolyzed in a muffle furnace at 623 K for 30 min to furnish its carbonized analogue (CMOP). The adsorbents showed favorable physicochemical attributes. The effects of operational parameters such as initial OFX solution pH and concentration, adsorbent dosage, temperature and contact time on OFX removal were investigated. At equilibrium, optimal removal efficiencies of 90.98% and 99.84% were achieved at solution pH 5 for AMOP and CMOP, respectively. The equilibrium adsorption data fitted into both the Langmuir and Freundlich isotherms. Gibbs free energy change (${\Delta}G^o$), enthalpy change (${\Delta}H^o$) and entropy change (${\Delta}S^o$) indicated that the adsorption of OFX was feasible, spontaneous, exothermic and occurred via the physisorption mode. Adsorption kinetics obeyed the Blanchard pseudo-second-order model. The results may find applications in the adsorptive removal of micro-contaminants of pharmaceutical origin from wastewater.

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.536-545
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• 2019

An experiment was conducted to evaluate the adsorptive removal of Pb(II) from an aqueous solution using a mixture of spent coffee grounds and chitosan on beads (CC-beads). Various parameters affecting the adsorption process of Pb(II) using CC-beads were investigated. Based on the experimental data, the adsorption kinetics and adsorption isotherms were analyzed for their adsorption rate, maximum adsorption capacity, adsorption energy and adsorption strength. Moreover, the entropy, enthalpy and free energy were also calculated by thermodynamic analysis. According to the FT-IR analysis, a CC-bead has a very suitable structure for easy heavy metal adsorption. The process of adsorbing Pb(II) using CC-beads was suitable for pseudo-second order kinetic and Langmuir model, with a maximum adsorption capacity of 163.51 (mg/g). The adsorption of Pb(II) using CC-beads was closer to chemical adsorption than physical adsorption. In addition, the adsorption of Pb(II) on CC-beads was exothermic and spontaneous in nature. CC-beads are economical because they are inexpensive and also the waste can be recycled, which is very significant in terms of the continuous circulation of resources. Thus, CC-beads can compete with other adsorbents.

• Resources Recycling
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• v.31 no.4
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• pp.49-55
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• 2022

In this study, the heavy metal ions (of Pb, Cd, Cr, and Hg) in wastewater were removed using a spent Li₂O-Al₂O₃-SiO₂-based crystallized glass previously used as an induction top plate material. Changes in the removal efficiency of heavy metals according to different reaction parameters, such as the amount of zeolite used as a heavy-metal adsorbent, adsorption time, initial concentration of the heavy metals, and pH of the initial solution, were investigated. As the amount of zeolite added increased, the heavy-metal removal efficiency also increased. Adsorption time had a considerable influence on adsorption characteristics, and the removal efficiency of all heavy metals increased with increasing adsorption time. In the case of Cd, the removal efficiency was greatly improved depending on the adsorption time. The initial concentration of the heavy-metal solution did not affect the removal efficiency; however, the initial pH of the heavy-metal solution affected the removal efficiency. More specifically, the removal efficiency of Cd increased while that of Pb and Cr decreased with increasing pH. The adsorption characteristics of Hg were not significantly affected by pH.

• Journal of Environmental Science International
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• v.27 no.9
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• pp.743-751
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• 2018

The objective of this study was to investigate the adsorption potential of chicken feathers for the removal of OrangeII (AO7) from aqueous solutions. Batch experiments were performed as a function of different experimental parameters such as initial pH, reaction time, feather dose, initial OrangeII concentration and temperature. The highest OrangeII uptake was observed at pH 1.0. Most of the OrangeII was adsorbed at 2 h and an adsorption equilibrium was reached at 6 h. As the amount of chicken feather was increased, the removal efficiency of OrangeII increased up to 99%, but its uptake decreased. By increasing the initial concentration and temperature, OrangeII uptake was increased. The experimental adsorption isotherm exhibited a better fit with the Langmuir isotherm than with the Freundlich isotherm, and maximum adsorption capacity from the Langmuir constant was determined to be 0.179244 mmol/g at $30^{\circ}C$. The adsorption energy obtained from the Dubinin-Radushkevich model was 7.9 kJ/mol at $20^{\circ}C$ and $30^{\circ}C$ which indicates the predominance of physical adsorption. Thermodynamic parameters such as ${\Delta}G^0$, ${\Delta}H^0$, and ${\Delta}S^0$ were -12.28 kJ/mol, 20.64 kJ/mol and 112.32 J/mol K at $30^{\circ}C$, respectively. This indicates that the process of OrangeII adsorption by chicken feathers was spontaneous and endothermic. Our results suggest that as a low-cost biomaterials, chicken feather is an attractive candidate for OrangeII removal from aqueous solutions.