• Journal of Environmental Science International
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• v.31 no.12
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• pp.1103-1115
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• 2022

The adsorption characteristics of four pesticides (phosphamidon, fenitrothion, triadimefon, and diniconazole) on natural clinoptilolite (CLI_N) and three synthetic zeolites were investigated. The synthetic zeolites included faujasite (FAU_F) synthesized from coal fly ash; the mixture of FAU and Na-P1 (FAU + Na-P1)_SF synthesized using Jeju scoria and coal fly ash at the ratio of 1.5 by weight; and waste fluid catalytic cracking catalyst (FCC_W). The distribution coefficient, K_D and the Freundlich constant, K_F decreased in the following sequence: FCC_W > FAU_F > (FAU + Na-P1)_SF > CLI_N among the zeolites and diniconazole>fenitrothion> triadimefon> phosphamidon among the pesticides. The pesticide adsorptivity increased with increasing temperature for FAU_F, (FAU+Na-P1)_SF and FCC_W, however, it decreased for CLI_N, regardless of the type of pesticide. The adsorptivity of pesticides was independent of pH for phosphamidon, fenitrothion and triadimefon, whereas it decreased with increasing pH for diniconazole, regardless of zeolite type.

• Membrane and Water Treatment
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• v.15 no.1
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• pp.41-50
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• 2024

Presence of hazardous dyes in water cause considerable risks to the human health and environment due to their potential toxicity and ecological disruptions. Therefore, in the present research, to suggest an alternative method for the retention of toxic Azocarmine G (ACG) dye from aqueous media, natural and H₂SO₄-modified acacia sawdust were performed for the first time as low-cost and efficient adsorbents. Based on batch experiments, it was determined that the best conditions for the developed dye retention process were an initial pH of 2.0 and an equilibrium time of 240 min. Analysis of the data using both pseudo-first order and pseudo-second order kinetic models showed that the retention of ACG onto the adsorbents predominantly occurred through chemical adsorption. Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models were employed to provide insights into the interaction between the adsorbate and adsorbent and the mechanism of the adsorption process. Maximum monolayer adsorption capacities of natural and H₂SO₄-modified acacia sawdust were determined as 28.01 and 64.90 mg g^-1, respectively by Langmuir isotherm model. Results of the study clearly indicated that the modification of acacia sawdust with H₂SO₄ leads to a substantial increase in the adsorption performance of anionic dyes.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.12 s.138
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• pp.1625-1631
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• 2004

The purpose of this study was to investigate dyeing properties of cotton fabrics by American fleabane extract. Effect of dyeing condition on dye uptake and effect of mordanting on dye uptake, color change and colorfastness were explored. Its affinity to cotton fiber was considerably lower than wool, and its hydrogen bonding was involved in the absorption of American fleabane colorants to cotton fiber. K/S value of pre­mordanting was higher than sim-mordanting or post-mordanting. Except that Sn mordanted showed high K/S value, it did not significantly increase. American fleabane produced mainly yellowish color on mordants and mordanting method. Cotton fabrics showed generally high colorfastness except colorfastness to washing.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.969-976
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• 2004

Cassava peelings waste, which is both a waste and pollutant, was chemically modified using mercaptoacetic acid (MAA) and used to adsorb $Cu^{2+}\;and\;Cd^{2+}$ from aqueous solution over a wide range of reaction conditions at $30^{\circ}C$. Acid modification produced a larger surface area, which significantly enhanced the metal ion binding capacity of the biomass. An adsorption model based on the $Cu^{2+}/Cd^{2+}$ adsorption differences was developed to predict the competition of the two metal ions towards binding sites for a mixed metal ion system. The phytosorption process was examined in terms of Langmuir, Freundlich and Dubinin-Radushkevich models. The models indicate that the cassava waste biomass had a greater phytosorption capacity, higher affinity and greater sorption intensity for $Cu^{2+}\;than\;Cd^{2+}$. According to the evaluation using Langmuir equation, the monolayer binding capacity obtained was 127.3 mg/g $Cu^{2+}$ and 119.6 mg/g $Cd^{2+}$. The kinetic studies showed that the phytosorption rates could be described better by a pseudo-second order process and the rate coefficients was determined to be $2.04{\times}10^{-3}\;min^{-1}\;and\;1.98{\times}10^{-3}\;min^{-1}\;for\;Cu^{2+}\;and\;Cd^{2+}$ respectively. The results from these studies indicated that acid treated cassava waste biomass could be an efficient sorbent for the removal of toxic and valuable metals from industrial effluents.

• Textile Coloration and Finishing
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• v.3 no.2
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• pp.34-42
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• 1991

The effects of electrolyte on dyeing properties of cotton fiber with Congo Red have been studied at 90, 70 and $40^{\circ}C$. Each dyeing carried into an infinite bath with $1\times10^{-4}$ mol/l of Congo Red and with various concentration of electrolytes. The results obtained from this study were as follow; 1. The equilibrium adsorption of dye $(C_\infty)$ values decreased with increasing dyeing temperature, $C_\infty$ values increased in the order KCl>NaCl>LiCl. 2. The values of apparent diffusion coefficients $(D_a)$ increased with increasing dyeing temperature, but $D_a$ values decreased in the order KCl$D_a$ values decreased with increasing electrolyte concentration. 4. Effect of electrolytes decreased with increasing dyeing temperature. 5. The values of standard affinities of dyeing $(-\triangle\mu^{\circ})$, the standard heats of dyeing $(-\triangleH^{\circ})$, and the standard entropies $(-\triangleS^{\circ})$, increased in the order KCl>NaCl>LiCl. 6. Equilibrium adsorption isotherm curve were Freundlich type, and in the Equation y=a.x$^{n}$ , the values of a and n increased in the order KCl>NaCl>LiCl. 7. The value of $-\triangle\mu^{\circ}$, $-\triangleH^{\circ}$, and $-\triangleS^{\circ}$, decreased with increasing electrolyte concentration.

• Asian Journal of Atmospheric Environment
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• v.10 no.2
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• pp.99-113
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• 2016

In order to improve the portability of basic absorbents monoethanolamine (MEA) and glycine (Gly), both were supported on microporous activated carbon (AC). Chemical modification by alkali-metal ion exchange (of Li, Na, K) was carried out on Gly-based absorbents. All supported absorbents were subjected to $CO_2$ absorption capacity (pure $CO_2$) and selectivity (indoor level) tests. Textural and chemical characterizations were carried out on test sorbents. All impregnation brought about significant reduction of specific surface area and microporosity of the adsorbent Depreciation in the textural properties was found to result to reduction in pure $CO_2$ sorption. Contrarily, low-level $CO_2$ removal capacity was enhanced as the absorbent dosage increases, resulting in supported 5 molar MEA in methanol solution. Adsorption capacities were improved from 0.016 and 0.8 in raw ACs to 1.065 mmol/g for MEA's. Surface chemistry via X-ray photoelectron spectroscopy (XPS) of the supported sorbents showed the presence of amine, pyrrole and quaternary-N. In reducing sequence of potency, pyridine, amine and pyrrolic-N were noticed to contribute significantly to $CO_2$ selective adsorption. Furthermore, the adsorption isotherm study confirms the presence of various SNGs heterogeneously distributed on AC. The adsorption mechanism of the present AC adsorbents favored Freundlich and Langmuir isotherm at lower and higher $CO_2$ concentrations respectively.

• Journal of Environmental Science International
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• v.7 no.4
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• pp.559-564
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• 1998

The effects of temperature, initial $Pb^{2+}$concentration and initial sludge concentration on the initial $Pb^{2+}$ removal rate and maximal $Pb^{2+}$removal amounts in activated sludge, respectively, were investigated. The removal of $Pb^{2+}$ in activated sludge was proved to be temperature-dependent process. The initial $Pb^{2+}$ removal rate increased from 187.5 to 261.4 mg $Pb^{2+}$/g sludge dry weight min, in response to the promoted temperature from 1$0^{\circ}C$ to 6$0^{\circ}C$, while the maximal $Pb^{2+}$removal amount (78.5 mg $Pb^{2+}$/g sludge dry weight) occurred at 30t . As the initial $Pb^{2+}$concentration increased from 36 to 228 mg $Pb^{2+}$/L at the constant temperature of 30C and initial sludge concentration of 1.5 g sludge dry weight/L, the time to reach an equilibrium state was almost independent of the initial $Pb^{2+}$concentration and the equilibrium $Pb^{2+}$/removal amount was increased Irom 41.9 to 73.6 mg $Pb^{2+}$/g sludge dry weight. On the contrary, the equilbrium $Pb^{2+}$ emoval amount was decreased from 87.7 to 65.3 mg $Pb^{2+}$/g sludge dry weight as the in- crease of initial sludge concentration from 0.22 to 1.76 g sludge dry weight/L.

• Journal of Environmental Science International
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• v.20 no.10
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• pp.1337-1345
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• 2011

The removal performances of divalent heavy metal ions ($Pb^{2+}$, $Cu^{2+}$, $Cd^{2+}$, $Sr^{2+}$ and $Mn^{2+}$) were studied using the Na-P1 zeolite synthesized from Jeju scoria in the batch and continuous fixed column reactor. The uptakes of heavy metal ions by synthetic Na-P1 zeolite decreased in the order of $Pb^{2+}$ > $Cu2^{2+}$ > $Cd^{2+}$ > $Sr^{2+}$ > $Mn^{2+}$ based on the selectivity of each ion to ionic exchange site of Na-P1 zeolite for single and mixed solutions in batch or continuous fixed column reactor. For mixed solution, each heavy metal ion uptake was lower than that in single solution, and especially the uptake for $Mn^{2+}$ decreased greatly. In batch reactor, the uptakes of heavy metal ions by synthetic Na-P1 zeolite were described by Freundlich or Langmuir equation, but they followed the former better than the latter. In continuous fixed column reactor, the maximum ion exchange capacity obtained for each of heavy metal ions, was about 90----- of that in batch reactor. The uptakes of heavy metal ions by synthetic Na-P1 zeolite increased with the increase of initial heavy metal concentration and solution pH, and the decrease of the amount and particle size of synthetic zeolite.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.8
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• pp.606-616
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• 2011

The objectives of this study were to evaluate the applicability of adsorption models for adsorption properties of adsorbents. For this study, adsorption experiment of $NO_3^-$ ion using anion exchange resin has been investigated under adsorption equilibrium and kinetic in bach process. Adsorption equilibrium experiment were carried out that two conditions is change of adsorbate concentration and change of adsorbent weight. Experiment results have been analyzed by adsorption isotherm models, energy models and kinetic models. Under the condition of change of adsorbate concentration was best described by Sips and Redlich-Perterson isotherm models. However case of change of adsorbent weight was described by Langmuir isotherm models. It seems reasonable to assume that isotherm model was dominated by multiple mechanism according to experiment condition.

• Environmental Engineering Research
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• v.17 no.3
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• pp.133-138
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• 2012

Polyvinyl alcohol/alginate hydrogel beads containing Mg-Al layered double hydroxide (LDH-PVA/alginate beads) were synthesized for phosphate removal. Results showed that blending PVA with the LDH-alginate beads significantly improved their stability in a phosphate solution. The kinetic reaction in LDH-PVA/alginate beads reached equilibrium at 12 hr-post reaction with 99.2% removal. The amount of phosphate removed at equilibrium ($q_e$) was determined to be 0.389 mgP/g. The equilibrium data were described well by the Freundlich isotherm with the distribution coefficient ($K_F$, 0.638) and the constant (n, 0.396). Phosphate removal in LDH-PVA/alginate beads was not sensitive to solution pH. Also, the removal capacity of LDH-PVA/alginate beads ($q_e$, 1.543 mgP/g) was two orders of magnitude greater than that of PVA/alginate beads ($q_e$, 0.016 mgP/g) in column experiments. This study demonstrates that LDH-PVA/alginate beads with a higher chemical stability against phosphate compared to LDH-alginate beads have the potential for phosphate removal as adsorptive media.