• Journal of Korean Society on Water Environment
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• v.21 no.1
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• pp.14-20
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• 2005

A feasibility study has been conducted regarding the application of waste coffee grounds as an adsorbent for the treatment of nickel ion containing wastewater. The major variables which considered to influence the adsorbability of nickel ion were its initial concentration, reaction temperature, pH, and coexisting ion. The specific surface area of coffee grounds used in the experiment was found to be ca. $39.67m^2/g$, which suggesting its potential applicability as an adsorbent due to its relatively high surface area. In the experimental conditions, more than 90% of the initial amount of nickel ion was shown to adsorb within 15 minutes and equilibrium in adsorption was attained after 3 hours. The adsorption behavior of nickel ion was well explained by Freundlich model and kinetics study showed that the adsorption reaction was second-order. Adsorption was reduced with temperature and its change of enthalpy in standard state was estimated to be -807.05 kJ/mol. Arrhenius equation was employed for the calculation of the activation energy of adsorption and nickel ion was observed to adsorb on coffee grounds exoentropically based on thermodynamic estimations. As pH rose, the adsorption of nickel ion was diminished presumably due to the formation of cuboidal complex with hydroxide ion and the coexistence of cadmium ion was found to decrease the amount of nickel ion adsorption, which was proportional to the concentration of cadmium ion.

• Journal of Environmental Health Sciences
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• v.24 no.2
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• pp.20-31
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• 1998

There is a need for waste recycling. This study was carried out to investigate removal efficiency of TCE in water treatment with adsorbent made from coffee grounds which obtained after extraction of coffee through hot water. The removal of TCE in synthetic Waste water using adsorbents was examined varying dose, concentration and temperature on a laboratory scale. The results were as followed 1. As much as 95% TCE remogal was possible with adsorbent made from coffee grounds at an adsorbent dose over 2.5 g/l under the test conditions. 2. The removal rate of TCE was propotional to weight of adsorbent made from coffee grounds (0.025, 0.1, 0.3, 0.5 g). 3. In the effect of temperature, as temperature of wastewater was high, the rate of removal was increased. 4. Iodine number (865 mg/g) of adsorbent made from coffee grounds was not higher than that (1123 mg/g) of adsorbent made from coconut. But, in considering adsorption capacity, Iodine number was inapplicable to adsorbent made from coffee grounds. 5. Generally, Freundlich's equation applies to adsorption in wastewater. In case of TCE, slope (1/n) was 0.83, 1.06 and intercept (k) was 456.18, 405.19 at 150, 300 ppb respectively (average r=0.904, 0.933).

• Applied Chemistry for Engineering
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• v.31 no.5
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• pp.495-501
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• 2020

In this study, zirconium fumarate of metal-organic framework (MOF-801) was solvothermally synthesized at 130 ℃ and characterized through powder X-ray diffraction (PXRD) analyses and porosity measurements from N₂ sorption isotherms at 77 K. The ability of MOF-801 to act as an adsorbent for the phosphate removal from aqueous solutions at 25 ℃ was investigated. The phosphate removal efficiency (PRE) obtained by 0.05 g/L adsorbent dose at an initial phosphate concentration of 60 ppm after 3 h was 72.47%, whereas at 5 and 20 ppm, the PRE was determined to be 100% and 89.88%, respectively, after 30 min for the same adsorbent dose. Brunauer-Emmett-Teller (BET) surface area and pore volume of the bare MOF-801 sample were 478.25 ㎡/g and 0.52 ㎤/g, respectively, whereas after phosphate adsorption (at an initial concentration of 60 ppm, 3 h), the BET surface area and pore volume were reduced to 331.66 ㎡/g and 0.39 ㎤/g, respectively. The experimental data of kinetic (measured at initial concentrations of 5, 20 and 60 ppm) and isotherm measurements followed the pseudo-second-order kinetic equation and the Freundlich isotherm model, respectively. This study demonstrates that MOF-801 is a promising material for the removal of phosphate from aqueous solutions.

• Polymer(Korea)
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• v.38 no.5
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• pp.557-565
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• 2014

Sodium alginate and chitosan are added to a $CaCl_2$ solution to prepare calcium-alginate-chitosan and calciumalginate gels. After dehydration through stoving, two types of adsorbent particles are obtained. The adsorption process of the particles obtained for low concentrations of $Sr^{2+}$ satisfies a second-order kinetic equation and the Freundlich adsorption model. The thermodynamic behaviors of the particles indicate that adsorption occurs via a spontaneous physical process. XPS pattern analysis is used to demonstrate the adsorption of $Sr^{2+}$ by calcium alginate and chitosan. By building an interaction model of the molecules of chitosan and alginate with $Ca^{2+}$ and $Sr^{2+}$ to calculate energy parameters, Fukui index, Mulliken charge, and Mulliken population, adsorption of $Sr^{2+}$ on the molecular chains of chitosan as well as the boundary of calcium-alginate-chitosan is observed to show weak stability; by contrast, adsorption between molecular chains is high.

• Korean Journal of Ecology and Environment
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• v.49 no.4
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• pp.289-295
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• 2016

The purpose of this study is to find out the effect of particle size of sediment on adsorption of fluoride. Particle size is classified as sand, silt and clay. Adsorption equilibrium time, adsorption isotherms and the effect of pH were investigated through batch tests. The $pH_{pzc}$ of sand, silt, clay was respectively 6, 8, 4.5 and AEC (anion exchange capacity) was highest in silt, respectively 0.0095, 0.0224, $0.014meq\;g^{-1}$. Adsorption of fluoride on the sediment was in equilibrium within 300 minutes from all particle size. The experimental data of isotherms at various pH were well explained by Freundlich equation. As the experimental results of the effect of pH, the adsorption efficiency of sand and silt were reduced after the $pH_{pzc}$. However, the adsorption efficiency of clay was maintained after the $pH_{pzc}$, and decreased rapidly higher than pH 12.

• Journal of Environmental Science International
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• v.27 no.11
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• pp.975-982
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• 2018

In this study, zeolite (Z-C1) was synthesized using a fusion/hydrothermal method from coal fly ash. The morphological structures of Z-C1 were confirmed to be highly crystalline with a cubic crystal structure. Exchange capacities of $Ca^{2+}$ and $Mg^{2+}$ ions in a single and a mixed solution reached equilibrium within 120 min. The exchange kinetics of these ions were well predicted by the pseudo-second-order rate equation. The exchange isotherms of the $Ca^{2+}$ and $Mg^{2+}$ ions matched the Langmuir isotherm better than the Freundlich isotherm. The maximum cation exchange capacities ($q_m$) obtained by the Langmuir isotherm model were 2.11 mmol/g (84.52 mg/L) and 1.13 mmol/g (27.39 mg/L) for the $Ca^{2+}$ and $Mg^{2+}$ ions, respectively.

• Korean Journal of Food Science and Technology
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• v.40 no.1
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• pp.111-114
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• 2008

Adsorption isotherm with the most fundamental information related to chromatography process is obtained experimentally. The adsorption isotherm of 2-deoxyuridine (dUrd) and 2-deoxycytidine (dCyd) with ${\mu}$-Bondapak $C_{18}$, static method was adopted in RP-HPLC. The concentrations of mobile and stationary phases were measured with different initial concentrations of dUrd and dCyd, 1, 3, 5, 7, 10 mg/mL, respectively. The adsorption isotherm data were applied by Freundlich, Langmuir, Sips, and Radke-Prausnitz model equations. As a result of the regression analysis, standard error between adsorption isotherm of dUrd and Radke-Prausnitz equation was very low, and adsorption isotherm of dCyd was in an agreement with Sips equation very well.

• Membrane and Water Treatment
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• v.10 no.6
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• pp.471-484
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• 2019

The complex combination of organic contaminants in the wastewater made water treatment challenging; hence, organic matter in water bodies is usually measured in terms of organic carbon. Since it is important to identify the types of compounds when deciding suitable treatment methods, this study implemented a quantitative and qualitative analysis of the organic matter content in an actual graywater sample from Ulsan, Republic of Korea using mass spectroscopy (MS). The graywater was treated using adsorption to remove the organic contaminants. Using orbitrap MS, the organic matter content between an untreated graywater and the treated effluent were compared which yielded a significant formula count difference for the samples. It was revealed that CHON formula has the highest removal count. Isotherm studies found that the Freundlich equation was the best fit with a coefficient of determination ($R^2$) of 0.9705 indicating a heterogenous GAC surface with a multilayer characteristic. Kinetics experiments fit the pseudo-second order equation with an $R^2$ of 0.9998 implying that chemisorption is the rate-determining step between the organic compounds and GAC at rate constant of $52.53g/mg{\cdot}h$. At low temperatures, the reaction between GAC and organic compounds were found to be spontaneous and exothermic. The conditions for optimization were set to achieve a maximum DOC and TN removal which yielded removal percentages of 94.59% and 80.75% for the DOC and TN, respectively. The optimum parameter values are the following: pH 6.3, 2.46 g of GAC for every 30 mL of graywater sample, 23.39 hrs contact time and $38.6^{\circ}C$.

• Applied Chemistry for Engineering
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• v.24 no.2
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• pp.184-189
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• 2013

In the present study, batch experiments were carried out for the utilizatioin of activated carbon as a potential adsorbent to remove a hazardous malachite green from an aqueous solution. The effects of various parameters such as temperature, contact time, initial concentration on the adsorption system were investigated. On the basis of adsorption data Langmuir and Freundlich adsorption isotherm model were also confirmed. The equilibrium process was described well by Langmuir isotherm model. From determined separation factor, the activated carbon could be employed as an effective treatment for removal of malachite green. From kinetic experiments, the adsorption process followed the pseudo second order model, and the adsorption rate constant ($k_2$) decreased with increasing both the initial concentration of malachite green and the adsoprtion temperature. Thermodynamic parameters like that activation energy, change of free energy, enthalpy, and entropy were also calculated to predict the adsorption nature. The activation energy calculated from Arrhenius equation indicated that the adsortpion of malachite green on the zeolite was physical process. The negative Gibbs free energy change ($\Delta$G = -3.68~-7.76 kJ/mol) and the positive enthalpy change ($\Delta$H = +26.34 kJ/mol) indicated the spontaneous and endothermic nature of the adsorption in the temperature range of 298~318 K.

• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.356-361
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• 2018

It is common to analyze volatile organic compound (VOC) or semi-VOC (SVOC) in a sample composed of a complex matrix consisting of multiple components such as bloods through a separation process. Adsorption is a physical phenomenon in which certain components accumulate on the surface of other phases. In order to overcome difficulties in the pretreatment process, an adsorption is frequently used. Solid phase microextraction (SPME) equipment with porous carbon carboxen (CAR) is an example of adsorption application. In this study, the adsorption of 4-octylphenol to carboxen was examined. To do so, the extraction efficiency for such solvents as dichloromethane ($CH_2Cl_2$, DCM), ethylacetate ($CH_3COOC_2H_5$, EA) and diethylether ($C_2H_5OC_2H_5$, $Et_2O$) was studied and also the derivatization reaction for 4-octylphenol with reagents of bistrimethylsilyltrifluoroacetamide (BSTFA), methylchloroformate (MCF) and pentafluorobenzylbromide (PFBBr) was compared. The combination of DCM and BSTFA showed good performance thus they were adopted for this study. Thermodynamic adsorption experiments showed that the adsorption process was endothermic and Freundlich isotherm equation was more suitable than Langmuir isotherm. It was also found that the adsorption followed a pseudo-$2^{nd}$ order kinetic model.