Sustainable porous polymers for gas capture, water treatment, and catalysis

Cafer T. Yavuz(야부즈자패르타야르) 한국고분자학회 2019 한국고분자학회 학술대회 연구논문 초록집 Vol.44 No.1

Amine loaded nanoporous covalent organic polymers for CO₂ capture

( Cafer T. Yavuz ) 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1

Control of carbon dioxide emissions without significant penalties requires effective CO₂ scrubbing from point sources, such as fossil fuel burning power plants, cement factories and steel making. Capturing process is the most costly; hence the research is directed to finding solutions to it. Solids with slight chemisorptive nature are identified as most likely candidates for a sustainable solution. Nanoporous (pore size < 100 nm) materials show considerable CO₂ uptakes and are likely to replace monoethanol amine (MEA) solutions for industrial CO₂ capture. We have developed nanoporous covalent organic polymers (COPs), which show significant capacities and selectivities for CO₂. To name a few, COP-1 shows 5.6 g/g CO₂ uptake at 200 bar and 45°C, COP-2 shows a CO₂/H₂ selectivity of over 10k:1, COP-79 has a CO₂/N₂ selectivity of 308 at 50°C, COP-83 has CO₂ uptake capacity of 5 mmol/g at 298 K and 1 bar and COP-97 showed an uptake of 8 % (w/w) CO₂ in 2 minutes from a simulated flue gas mixture (CO₂ 15%, H₂O 3.8%, He 81.2%, 40°C, flow rate : 80 mL/min). Chemical grafting of amines also show considerable enhancement, though a sweet spot exists. Our results point to an ideal nanoporous structure to be made from a highly porous, inexpensive, physisorptive solid, which is chemically modified with chemisorptive functionalities such as amines.

Gold Recovery using Porphyrin-based Polymer from Electronic Waste: Adsorbent Regeneration and Reuse

( Jieun Sona ),( Cafer T. Yavuz ),( Yeongran Hong ),( Thien Nguyen ),( Jong-in Han ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 ISSE 초록집 Vol.2019 No.-

Due to the rapid development of innovations, the amount of discarded electrical or electronic equipment, called electronic wastes, have been gradually increased over the world and as a consequence, the treatment of the wastes brought a great attention to many researchers. Despite its small amount, precious metals in electronic wastes have large potential values as a future secondary source of metals. However, separation and refining of these metals are complicated and none of them are chosen to be commercialized. As one of the promising adsorbents, porphyrin-based porous polymer, named COP-180, has been developed for the selective adsorption and separation of gold. Although the characteristics and adsorption abilities of COP-180 has been deeply investigated, the strategies on the desorption and recovery of adsorbed gold and the regeneration of the polymer are still unknown. Herein, a hydrometallurgical method for efficient gold desorption and recovery from COP-180 was suggested. Chloride, thiosulfate and thiourea, which are typical non-cyanide gold leaching solutions, were evaluated for gold desorption from the polymer. Leaching solution of thiourea in acidic condition provided the best desorption performance. The results of FTIR analysis showed that the structure of COP-180 was maintained during desorption with thiourea, while changes of structures were detected with acid chloride solution as it supported the suitability of thiourea in either gold desorption or adsorbent regeneration. The ratio of adsorbed gold over the polymer was varied to analyze its effect on desorption efficiency. The less amount of gold was adsorbed on the polymer, the higher gold desorption efficiency was obtained. More than 98% of the adsorbed gold was desorbed from COP-180 by the treatment of 0.1M of thiourea for 2 hours at 50°C. The regeneration and reusability of the adsorbent was evaluated in three consecutive cycles. All these present works suggested that the desorption method via acid thiourea can offer a workable way of efficient gold recovery and regeneration of the adsorbent.

A catalytic role of surface silanol groups in CO₂ capture on the amine-anchored silica support

Cho, Moses,Park, Joonho,Yavuz, Cafer T.,Jung, Yousung Royal Society of Chemistry 2018 Physical chemistry chemical physics Vol.20 No.17

<P>A new mechanism of CO2 capture on the amine-functionalized silica support is demonstrated using density functional theory calculations, in which the silica surface not only acts as a support to anchor amines, but also can actively participate in the CO2 capture process through a facile proton transfer reaction with the amine groups. The surface-mediated proton transfer mechanism in forming a carbamate-ammonium product has lower kinetic barrier (8.1 kcal mol<SUP>−1</SUP>) than the generally accepted intermolecular mechanism (12.7 kcal mol<SUP>−1</SUP>) under dry conditions, and comparable to that of the water-assisted intermolecular mechanism (6.0 kcal mol<SUP>−1</SUP>) under humid conditions. These findings suggest that the CO2 adsorption on the amine-anchored silica surface would mostly occur <I>via</I> the rate-determining proton transfer step that is catalyzed by the surface silanol groups.</P>

Enhanced Sorption Cycle Stability and Kinetics of CO₂ on Lithium Silicates Using the Lithium Ion Channeling Effect of TiO₂ Nanotubes

Lee, Joo Sung,Yavuz, Cafer T. American Chemical Society 2017 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.56 No.12

<P>Lithium silicate (Li4SiO4) is a promising high temperature CO2, sorbent because of its large CO2, capacity at elevated temperatures with low materials cost. However, the conventional nonporous Li4SiO4 shows very poor CO2, adsorption kinetics. Thus, a Li4SiO4-TiO2 nanotubes complex was synthesized where LiOH and fumed silica would be calcined around TiO2 nanotubes. TiO2 nanotubes in Li4SiO4 structure functioning as open highways, lithium ions were able to channel through the bulky structure and enhance the sorption kinetics, leading the total adsorption capacity to near theoretical values. Furthermore, cyclic studies at 700 degrees C revealed strong stability Over at least 10 cycles. These findings indicate that stability and kinetics of CO2, sorption can be greatly improved by the nanotube composites of known adsorbents.</P>

Highly optimized CO₂ capture by inexpensive nanoporous covalent organic polymers and their amine composites

Patel, Hasmukh A.,Yavuz, Cafer T. The Royal Society of Chemistry 2015 Faraday discussions Vol.183 No.-

<P>Carbon dioxide (CO<SUB>2</SUB>) storage and utilization requires effective capture strategies that limit energy penalties. Polyethylenimine (PEI)-impregnated covalent organic polymers (COPs) with a high CO<SUB>2</SUB> adsorption capacity are successfully prepared in this study. A low cost COP with a high specific surface area is suitable for PEI loading to achieve high CO<SUB>2</SUB> adsorption, and the optimal PEI loading is 36 wt%. Though the adsorbed amount of CO<SUB>2</SUB> on amine impregnated COPs slightly decreased with increasing adsorption temperature, CO<SUB>2</SUB>/N<SUB>2</SUB> selectivity is significantly improved at higher temperatures. The adsorption of CO<SUB>2</SUB> on the sorbent is very fast, and a sorption equilibrium (10% wt) was achieved within 5 min at 313 K under the flow of simulated flue gas streams. The CO<SUB>2</SUB> capture efficiency of this sorbent is not affected under repetitive adsorption–desorption cycles. The highest CO<SUB>2</SUB> capture capacity of 75 mg g<SUP>−1</SUP> at 0.15 bar is achieved under dry CO<SUB>2</SUB> capture however it is enhanced to 100 mg g<SUP>−1</SUP> in the mixed gas flow containing humid 15% CO<SUB>2</SUB>. Sorbents were found to be thermally stable up to at least 200 °C. TGA and FTIR studies confirmed the loading of PEIs on COPs. This sorbent with high and fast CO<SUB>2</SUB> sorption exhibits a very promising application in direct CO<SUB>2</SUB> capture from flue gas.</P>

Noninvasive functionalization of polymers of intrinsic microporosity for enhanced CO₂ capture

Patel, Hasmukh A.,Yavuz, Cafer T. The Royal Society of Chemistry 2012 Chemical communications Vol.48 No.80

<P>Modifying sorbents for the purpose of improving carbon dioxide capture often results in the loss of surface area or accessible pores, or both. We report the first noninvasive functionalization of the polymers of intrinsic microporosity (PIMs) where inclusion of the amidoxime functionality in PIM-1 increases carbon dioxide capacity up to 17% and micropore surface area by 20% without losing its film forming ability.</P> <P>Graphic Abstract</P><P>Noninvasive functionalization of the nitriles into amidoxime groups through post-modification of PIM-1 improves CO<SUB>2</SUB> uptake without deteriorating its film forming ability. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cc35392j'> </P>

Synthesis of covalent organic polymers for removing heavy metal ions with strong affinity

Dongah Ko,Mogens H. Jakobsen,Yuhoon Hwang,Cafer T. Yavuz,Henrik R. Andersen 대한환경공학회 2015 대한환경공학회 학술발표논문집 Vol.2015 No.10

Influence of Aminosilane Coupling Agent on Aromatic Polyamide/Intercalated Clay Nanocomposites

Alvi, Muhammad Usman,Zulfiqar, Sonia,Yavuz, Cafer T.,Kweon, Hee-Seok,Sarwar, Muhammad Ilyas American Chemical Society 2013 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.52 No.21

<P>Aminosilane grafted and diamine modified reactive montmorillonite was exploited to generate aromatic polyamide based nanocomposites. For better compatibility, the hydrophilic nature of montmorillonite was changed into organophilic using 1,4-phenylenediamine, and the hydroxyl groups present on the clay surface and edges were used to graft 3-aminopropyltriethoxysilane (APTS) on clay sheets. The dispersion of clay was monitored in the polyamide obtained from 1,4-phenylenediamine, 4,4′-oxydianiline, and isophthaloyl chloride. These chains were converted into carbonyl chloride ends to interact with free amine groups of grafted APTS and diamine. Thin films were probed for FTIR, XRD, SEM, TEM, tensile testing, TGA, and DSC measurements. The results described ample dispersion of clay in the nanocomposites with tensile strength increased 110% and elongation increased 172% upon the addition of 4–6 wt % clay. Thermal decomposition temperatures of the nanocomposites were in the range 425–480 °C. The glass transition temperature increased up to 142.4 °C with 6 wt % addition of organoclay.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/iecred/2013/iecred.2013.52.issue-21/ie400463z/production/images/medium/ie-2013-00463z_0013.gif'></P>

Direct Access to Primary Amines and Particle Morphology Control in Nanoporous CO₂ Sorbents

Dogan, Nesibe A.,Ozdemir, Ercan,Yavuz, Cafer T. Wiley (John WileySons) 2017 ChemSusChem Vol.10 No.10

<P>Chemical tuning of nanoporous, solid sorbents for ideal CO2 binding requires unhindered amine functional groups on the pore walls. Although common for soluble organics, post-synthetic reduction of nitriles in porous networks often fails due to insufficient and irreversible metal hydride penetration. In this study, a nanoporous network with pendant nitrile groups, microsphere morphology was synthesized in large scale. The hollow microspheres were easily decorated with primary amines through in situ reduction by widely available boranes. The CO2 capture capacity of the modified sorbent was increased to up to four times that of the starting nanoporous network with a high heat of adsorption (98 kJ mol(-1)). The surface area can be easily tuned between 1 and 354 m(2)g(-1). The average particle size (ca. 50 mu m) is also quite suitable for CO2 capture applications, such as those with fluidized beds requiring spheres of micron sizes.</P>