• Applied Chemistry for Engineering
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• v.5 no.1
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• pp.30-36
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• 1994

Reaction characteristics and correlations between the acidic property and catalytic activity of heteropoly acid catalyst on ETBE synthesis as a gasoline octane enhancer were investigated. The amount of pyridine adsorbed on heteropoly acid catalyst and catalytic activity in the synthesis of ETBE showed a good correlation. But ammonia failed to show such a correlation because of the complex formation of ammonia adsorbed and transition metal ions. In the case of supported catalyst catalytic activity and product distribution were mainly affected by the adsorption characteristics of TBA or iso-butene.

• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.63-68
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• 2001

A laboratory experiment was performed to invstigate the nitrate removal using FeCl$_3$ -treated activated carbon. Iron chloride(III) was coated onto the surface of activated carbon. The removal efficiency of nitrate was increased with increasing of FeCl$_3$ was used for coating material. About 22~26mg of Fe per unit g of activated carbon was adsorbed. The nitrate removal was not affected by the pH under the experiment range of pH, but the pH value in solution decrease to 3.5~4.0 after reaction. The removal efficiency of nitrate was increased with increasing of dosage of adsorbents. Ammonia was not detected and the Fe concentration as low as 0.22mg/$\ell$ was desorbed from the adsorbents. The adsorbents was regenerated using KCl solution, and recovery was 76.6% at 1 M of KCl. The adsorption of nitrate by FeCl$_3$-treated activated carbon followed the Freundlich isotherm equation and the Freundlich constant, 1/n, was 0.346. These results showed that the FeCl$_3$-treated activated carbon could serve as the basis of a useful nitrate removal.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.361-364
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• 2002

BAC (biological activated carbon) process is a combination of biodegradation and active carbon adsorption. Pre-ozonation of raw water increased in biodegradable organic fraction. This study is to investigate the enhancement of dissolved organic matter removals by pre-ozonation process combined with BAC process at a semi-pilot scale. By biodegradation improvement in pre-ozonation process. the charge of adsorption was reduced and the life of biological activated carbon is extended. And, 48 % of total DOC was remove in the upper compartment of BAC column. The removal of the nitrogen-ammonia shows a considerably high removal ratio with 75.9 %.

• Applied Chemistry for Engineering
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• v.18 no.3
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• pp.255-261
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• 2007

The catalytic behavior of the manganese oxides was studied for the selective catalytic reduction with ammonia at a low temperature condition under $200^{\circ}C$. Outlet unreacted ammonia increases with decreasing temperature and increasing $NH_3/NOx$ mole ratio, however $NO_2$ shows an opposite result. $NO_2$ is generated by the adsorption of NO on the catalyst and the following oxidization to nitrates. Unreacted NH3 slip is not observed even at the $NH_3/NOx$ feed ratio above 1.0 due to the reaction between formed nitrates on the catalyst and adsorbed ammonia. The addition of Zr increases $NO_2$ generation, whereas the addition of CeO2 on the catalyst decreases $NO_2$ generation. Furthermore, the additon of the metal oxide induce DeNOx efficiency to reduce.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.3
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• pp.367-375
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• 2006

Sequencing Batch Reactor (SBR) is well adopted for community wastewater treatment for its simplicity, performance and various advantageous treatment options. SBR is now drawing attention for its process modification such as coupled with membrane bioreactor, reverse osmosis or applying different media to achieve high removal efficiency. This study focused on the improved efficiency of carbon, nitrogen and phosphorous removal by applying zeolite materials called bioceramics to the SBR. Two laboratory-scale SBR units were operated in the same operating conditions - one with bioceramics called Bioceramic SBR (BCSBR) and the other without bioceramics used as control. Routine monitoring of COD, TP, $NH_3-N$, $NO_3-N$ was performed throughout this study. COD removal was about 80% to 100% and phosphorous removal was about 60% in the process whereas $NH_3-N$ removal efficiency was found to be 99.9% in the BCSBR unit. Addition of bioceramics also improved sludge characteristics such as sludge dewaterability, specific gravity and particle size. BCSBR can withstand high ammonia shock loading leading to the better treatment capacity of high ammonia containing wastewater. The cause of improved removal efficiencies within the biological reactor could be attributed to the biochemosorption mechanisms of bioceramics. Absorption/adsorption or desorption capacity of bioceramics was tested through laboratory experiments.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.907-914
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• 2019

Ammonia (NH₃) that reacts with nitric or sulfuric acid in the air is the major culprit contributing to the formation of fine particulate matter (PM_2.5). NH₃ volatilization mainly originates from nitrogen fertilizer and livestock manure applied to arable soil. Cation exchange capacity (CEC) of peat moss (PM) and zeolite (ZL) is high enough to adsorb ammonium (NH₄⁺) in soil. Therefore, they might inhibit volatilization of NH₃. The objective of this study was to compare the effect of PM and ZL on NH₃ volatilization from upland soil. For this, a laboratory experiment was carried out, and NH₃ volatilization from the soil was monitored for 12 days. PM and ZL were added at the rate of 0, 1, 2, and 4% (wt wt^-1) with 354 N g m^-2 of urea. Cumulative NH₃-N volatilization decreased with increasing addition rate of both materials. Mean value of cumulative NH₃-N volatilization across application rate with PM was lower than that with ZL. CEC increased with increasing addition rate of both materials. While the soil pH increased with ZL, it decreased with PM. Increase in CEC resulted in NH₄⁺ adsorption on the negative charge of the external surface of both materials. In addition, decrease in soil pH hinders the conversion of NH₄⁺ to NH₃. Based on the above results, the addition of PM or ZL could be an optimum management to reduce NH₃ volatilization from the soil. However, PM was more effective in decreasing NH₃ volatilization than ZL due to the combined effect of CEC and pH.

• Journal of The Korean Society of Grassland and Forage Science
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• v.44 no.2
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• pp.133-139
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• 2024

This study aimed to evaluate the efficiency of combining acidification with adsorbents (zeolite and biochar) to mitigate the environmental impacts of pig slurry, focusing on ammonia (NH₃) emission and nitrate (NO₃^-) leaching. The four treatments were applied: 1) pig slurry (PS) alone as a control, 2) acidified PS (AP), 3) acidified pig slurry with zeolite (APZ), and 4) acidified pig slurry with biochar (APB). The AP mitigates NH₃ emission and NO₃^- leaching compared to PS alone. Acidification reduced the cumulative NH₃ emission and its emission factor by 35.9% and 12.5%, respectively. The APZ and APB increased NH₄⁺-N concentration, with the highest level in APB, compared to AP. The NH₄⁺ adsorption capacity of APB (0.90 mg g^-1) was higher than that of APZ (0.63 mg g^-1). The APB and APZ treatments induced less NH₃ emission compared to AP. The cumulative NH₃ emission was reduced by 12.2% and 27.6% in APZ and APB, respectively, compared to AP treatment. NO₃^- leaching began to appear on days 12 and 13, and its peak reached on days 16 and 17, which were later than AP. The cumulative NO₃^- leaching decreased by 17.7% and 25.0% in APZ and APB, respectively, compared to AP treatment. These results suggest that combining biochar or zeolite with acidified pig slurry is an effective method to mitigate NH₃ emission and NO₃^- leaching, with biochar being particularly effective.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.532-539
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• 2011

The physical and chemical properties of the dried low rank coals (LRCs) before and after the surface treatment using ozone and ammonia were characterized in this study. The contents of moisture, volatiles, fixed carbon and ash consisting of dried LRCs before the surface treatment were about 2.0, 44.8, 44.9 and 8.9%, respectively. Also, it was composed of carbon of 62.66%, hydrogen of 4.33%, nitrogen of 0.94%, oxygen of 27.01% and sulfur of 0.09%. The dried LRCs was surface-treated with the various dry methods using gases such as ozone at room temperature, ammonia at $200^{\circ}C$ and then the dried LRCs before and after the surface treatment were characterized by the various analysis methods such as FT-IR, TGA, proximate and elemental analysis, caloric value, ignition test, adsorption of $H_2O$ and $NH_3-TPD$. As a result, the oxygen content increased and the calorific value, ignition temperature and the contents of carbon and hydrogen relatively decreased because the oxygen-contained functional groups were additionally generated by the surface oxidation with ozone which plays a role as an oxidant. Also, its $H_2O$ adsorption ability got higher because the hydrophilic oxygen-contained functional groups were additionally generated by the surface oxidation with ozone. On the other hand, it was confirmed that the dried LRCs after the surface treatment with $NH_3$ at $200^{\circ}C$ have the decreased oxygen content, but the increased calorific value, ignition temperature and contents of carbon and hydrogen because of the decomposition of oxygen-contained functional groups the on the surface. In addition, the $H_2O$ adsorption ability was lowered bucause the surface of the dried LRCs might be hydrophobicized by the loss of the hydrophilic oxygen-contained functional groups. It was concluded that the various physico-chemical properties of the dried LRCs can be changed by the surface treatment.

• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.1 s.20
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• pp.69-73
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• 2004

Control if Sediment is very important in prawn farm due to the eruption of toxic materials such as unionized $H_{2}S,\;NH_{3}\;and\;NO_3$. In this study, column test was conducted with filter media such as activated carbon, zeolite, oyster shell and iron chloride to evaluate the reduction of toxicity from sediment. ammonia-N($NH_3$) was effectively removed by Zeolite and oyster shell. It was indicated that ammonium ion($NH_4^+$) was removed by ion exchange of zeolite. And the ammonia in the column of oyster shell was existed as the form of $NH_4^+$, which is not toxic for prawn because oyster shell was stably kept at $8{\sim}9g$ of pH. Therefore, some of ammonia($NH_4^+$) was removed by oyster shell. Hydrogen sulfide and COD were effectively removed by adsorption of activated carbon and a partial removal of hydrogen sulfide was accomplished by Oyster shell. Phosphorous was removed by activated carbon, oyster shell and iron chloride. In prawn farm, the concentration of ammonia was increased with increase of pH by algae photosynthesis in the column of activated carbon, zeolite and iron chloride, but it was revealed that pH was stably kept in the column of oyster shell.

• Asian Journal of Atmospheric Environment
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• v.11 no.1
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• pp.15-28
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• 2017

The adsorptive removal properties of synthetic A4 zeolite were investigated against a total of 16 offensive odors consisting of reduced sulfur compounds (RSCs), nitrogenous compounds (NCs), volatile fatty acids (VFAs), and phenols/indoles (PnI). Removal of these odors was measured using a laboratory-scale impinger-based adsorption setup containing 25 g of the zeolite bed (flow rate of $100mL\;min^{-1}$). The high est and lowest breakthrough (%) values were shown for PnIs and RSCs, respectively, and the maximum and minimum adsorption capacity (${\mu}g\;g^{-1}$) of the zeolite was observed for the RSCs (range of 0.77-3.4) and PnIs (0.06-0.104), respectively. As a result of sorptive removal by zeolite, a reduction in odor strength, measured as odor intensity (OI), was recorded from the minimum of approximately 0.7 OI units (indole [from 2.4 to 1.6]), skatole [2.2 to 1.4], and p-cresol [5.1 to 4.4]) to the maximum of approximately 4 OI units (methanethiol [11.4 to 7.5], n-valeric acid [10.4 to 6.5], i-butyric acid [7.9 to 4.4], and propionic acid [7.2 to 3.7]). Likewise, when removal was examined in terms of odor activity value (OAV), the extent of reduction was significant (i.e., 1000-fold) in the increasing order of amy acetate, i-butyric acid, phenol, propionic acid, and ammonia.