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Rehman, Aafaq ur,Baek, Jin Woong,Rene, Eldon R.,Sergienko, Natalia,Behera, Shishir Kumar,Park, Hung-Suck Elsevier 2018 Process safety and environmental protection Vol.118 No.-
<P><B>Abstract</B></P> <P>Climate change issues and acid rain episodes have triggered new research directions and the conceptualization of new preventive approaches to reduce toxic gases from entering the environment. The reduction of carbon dioxide (CO<SUB>2</SUB>) levels in the indoor environment are also one of the challenging human safety issues during emergency incidents and rescues; for instance, a building fire. The use of an activated carbon fiber (ACF) based mask is not only effective to filter CO<SUB>2</SUB> but it is also practically easy to use during such demanding situations. Such modified adsorbents will have high adsorption volume, fast adsorption rates and good thermal, acid and alkaline resistance properties. For the emergency mode considering fires, the major task is atmospheric recovery. Thus, CO<SUB>2</SUB> concentration in the post-fire smoke could be high. The smoke in the room causes suffocations and unconsciousness leading to fatal injuries. In this study, ACF was modified using copper nitrate trihydrate [Cu (NO<SUB>3</SUB>)<SUB>2</SUB> <SUP>.</SUP>3H<SUB>2</SUB>O] by impregnation and carbonization (450°C), followed by its characterization. The modified ACF (Cu-ACF-12) showed large surface area (1147m<SUP>2</SUP> g<SUP>−1</SUP>), high micropore volume (0.45cm<SUP>3</SUP> g<SUP>−1</SUP>) and an average pore size of 1.57nm. CO<SUB>2</SUB> removal tests were carried out in a lab scale fixed bed adsorption column using the modified ACF. The process parameters were optimized based on a Box-Behnken Design (BBD) and tested in the following ranges: gas flow rate – 150–250mlmin<SUP>−1</SUP>, moisture content – 0–40% and modification of the ACF impregnated with copper (Cu) – 4–12wt.%. The experimental results were statistically interpreted to elucidate the main and interaction effects. The modification of ACF showed positive effects on CO<SUB>2</SUB> removal, while gas flow rate and moisture content decreased the CO<SUB>2</SUB> removal. Under the optimal conditions, (gas flow rate – 150mlmin<SUP>−1</SUP>, moisture content – 0% and modification of the ACF – 8%), CO<SUB>2</SUB> removal capacity of 2.31mmol of CO<SUB>2</SUB> g<SUP>−1</SUP> Cu-ACF was obtained.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Modified activated carbon fiber (ACF) for CO<SUB>2</SUB> removal. </LI> <LI> Fixed bed adsorption column using modified ACF for process parameters optimization. </LI> <LI> Optimum CO<SUB>2</SUB> removal capacity of 2.31mmol of CO<SUB>2</SUB> g<SUP>−1</SUP> Cu-ACF at gas flow rate: 150mlmin<SUP>−1</SUP>, moisture content: 0% and modification of the ACF: 8%. </LI> <LI> Close agreement between the predicted and observed CO<SUB>2</SUB> removal capacity. </LI> </UL> </P>
Effect of chemical impregnation on activated carbon fabrics for carbon dioxide capture
( Aafaq Ur Rehman ),( Jin Woong Baek ),( Muhammad Sohail ),( Pham Viet Nguyen ),( Manyandi Venkatesan ),( Shrestha Keshab ),( Hung Suck Park ) 한국폐기물자원순환학회(구 한국폐기물학회) 2016 한국폐기물자원순환학회 춘계학술발표논문집 Vol.2016 No.-
Climate change and acid rain triggered new research opportunities to reduce carbon emissions and acidic gases. However, indoor reduction of CO<sub>2</sub> and acid gases are also the challenging safety issues in building fire. To develop a safety mask with enhanced carbon dioxide adsorption capacity, activated carbon fabrics (ACF) was prepared by copper (II) nitrate trihydrate and ammonium chloride impregnation followed by carbonization and CO<sub>2</sub> adsorption tests were conducted in lab scale reactor with 150 mm in length and internal diameter of 16.12 mm at different moisture conditions (0-40%). Surface area, pore size distribution and cumulative pore volume of ACF samples were examined with BET surface area and porosity analyzer. ACF impregnated with copper showed large surface area (1087 m<sup>2</sup>·g<sup>-1</sup>) and high micre pore volume (0.40 cm<sup>3</sup>·g<sup>-1</sup>) with average pore size of 1.66 nm, while ACF modified with ammonium showed surface area of 861 m<sup>2</sup>·g<sup>-1</sup> and micro pore volume (0.38 cm<sup>3</sup>·g<sup>-1</sup>) with average pore size of 2.07 nm. This results show that carbonization of fabrics at 450℃ contribute to enhancing surface area as well as micro pore volume. The carbon uptake of ACF modified with ammonium chloride and copper nitrate trihydrate were 49.3 and 85 mg CO<sub>2</sub>/g ACF, 29 and 90 mg CO<sub>2</sub>/g ACF in dry and 25% moisture contents, respectively. As moisture content increase to 25%, CO<sub>2</sub> adsorption capacity increase to 2-3 times higher than those at dry conditions in both chemicals impregnation. However, further increase in the moisture content to 40% decease adsorption capacity of ACF due to change in functionalities of impregnated chemicals.
Preparation and Characterization of ZSM-5 zeolite composite membranes for Acetic Acid Dehydration
Aafaq ur Rehman,Churl-Hee Cho 한국막학회 2017 한국막학회 총회 및 학술발표회 Vol.2017 No.11
ZSM-5 zeolite membranes can be tuned for hydrophilicity with varied Si/Al ratio allowing dehydration of various organic-water mixtures. α-Al2O3 supports were dip coated by silicalite-1 seed particles, dried (180°C for 12h) and calcined (450°C for 5h) for the secondary growth process. Hydrothermal synthesis of ZSM-5 zeolite membranes was carried out at 180 °C for 48 h. SEM and XRD results indicate excellent crystal morphology with high purity and preferred orientation. Prepared membranes showed a maximum perm-selectivity of 24 at 30°C for H2/SF6 separation. At that condition, H2 and SF6 permeance was 212 and 9 GPU, respectively. It was found that the permeance was higher at low Si/Al ratios, so it is expected that prepared membrane can be applicable for acetic acid dehydration.
Thiomer를 활용한 ASR 소각재의 중금속 고형화 특성 연구
백진웅,( Aafaq Ur Rehman ),( Pham Viet Nguyen ),( Sun Guohua ),( Manyandi Venkatesan ),( Shrestha Keshab ),( Srinivasa Reddy Mallampati ),박흥석 한국폐기물자원순환학회(구 한국폐기물학회) 2016 한국폐기물자원순환학회 춘계학술발표논문집 Vol.2016 No.-
우리나라는 연간 많은 양의 원유를 해외에서 수입하며, 원유는 정제과정을 거쳐 다양한 석유제품으로 생산된다. 원유의 정제과정 중 탈황공정에서는 산업부산물인 부생유황이 생산되는데, 저유황유의 수요증가에 따라 부생유황의 생산량도 증가하는 추세에 있다. 부생유황에 유기물을 첨가하여 유황을 개질하면 유황폴리머바인더(Thiomer)가 되는데 시멘트와 아스팔트를 대체하는 친환경 건설자재로 활용되고 있다. 한편, 폐 자동차의 재활용률 기준의 향상에 따른 자동차파쇄잔재물(ASR)의 에너지화로 중금속 함량이 높은 ASR 소각재 발생량도 증가하고 있어, 이를 환경적으로 안전하게 처리하며, 재활용하는 방안이 필요한 실정이다. 본 연구는 유황폴리머바인더(Thiomer)를 활용한 ASR 소각재의 고형화를 위한 기초연구로 고형화에 따른 구조적 특성과 환경적 특성을 평가하였다. 이를 위해 ASR 소각재의 중금속함량을 측정하고, 유황폴리머바인더, 소각재 및 모래의 배합설계비에 따라 공시체(직경 50mm, 높이 100mm)를 제작하였다. 제작된 공시체는 24시간이 지난 후 탈형하고, 7일간 공기 중에서 양생하여 압축강도를 측정하였으며, 공시체를 5mm이하의 크기로 파쇄하여 중금속 용출농도를 측정하였다. 실험결과 고형화 후 압축강도는 유황폴리머바인더 40 wt%, 소각재 40 wt%, 모래 20 wt%의 배합설계비에서 최대 77.03MPa로 높은 강도가 나타났다. 중금속 용출은 지정폐기물판정 기준(Pb : 3.0 mg/l, Cu : 3.0 mg/l, Cd : 0.3 mg/l, Cr : 1.5 mg/l)보다 낮은 0.1 mg/l 이하로 고형화 효율이 90% 이상으로 나타났다. 이상의 결과는 ASR 소각재를 Thiomer로 고형화하여 건설자재로 활용함으로써 자동차 재활용률을 제고시킬 수 있는 가능성을 확인할 수 있었다.
Comparison of Landfill Gas Generation and Recovery from An Existing Facility at Ulsan, S. Korea
( Muhammad Sohail ),( Aafaq Ur Rehman ),( Beak Jin Woong ),( Yousuf Jamal ),( Hung-suck Park ) 한국폐기물자원순환학회(구 한국폐기물학회) 2015 한국폐기물자원순환학회 3RINCs초록집 Vol.2015 No.-
Comparison study of landfill gas generation and recovery was carried out for the enhancement of landfill gas (LFG) from Seongam landfill facility situated at Ulsan, South Korea. Field sampling and measurements at the site were performed in order to investigate the possibility of enhanced gas recovery. US Environmental Protection Agency (EPA) LandGEM mathematical model (version 3.02) and stoichiometric measurements were considered for the estimation of landfill gas generation. It was noted that the existing facility has limited gas recovery potential in comparison to prediction by EPA landGEM model. Reasons for this limited recovery are found to be the improper landfill covering, blockage of gas extraction pipe screen openings and improper gas management of leachate collection well. A proper landfill final cover, installation of cover for leachate collection well and dewatering system for removing blockage are suggested to reduce the gaseous emissions to the environment.