Copper recovery via polyelectrolyte enhanced ultrafiltration followed by dithionite based chemical reduction: Effects of solution pH and polyelectrolyte type

Chou, Yi-Hsuan,Choo, Kwang-Ho,Chen, Shiao-Shing,Yu, Jui-Hsuan,Peng, Ching-Yu,Li, Chi-Wang Elsevier 2018 Separation and purification technology Vol.198 No.-

<P><B>Abstract</B></P> <P>A chemical reduction process was proposed to recover copper from the retentate of polyelectrolyte enhanced ultrafiltration (PEUF). Three polyelectrolytes (PSS, PAA, and PEI) containing various functional groups and molecular weights were studied to explore their effects on the copper removal in PEUF and on the copper recovery by chemical reduction under various pH conditions. With PSS which contains sulfonic group, copper was removed reasonably well (ca. 75%) by PEUF even under acidic pH value of 3. With PAA which contains carboxylic group, copper removal was a bit low (∼60%) under pH 3.0 but increased substantially at pH 4.0. A branched PEI having amine group achieved the highest Cu removal of 94% at pH 3. The copper removal efficiency decreased slightly with increasing pH due to the high permeation of PEI through membrane.</P> <P>Chemical reduction achieved the complete copper recovery for solution containing PSS. The copper recovery efficiencies were more than 95% for PAA solution with pH values ranging from 3 to 9 at reaction time of one hour. For PEI, the recovery efficiencies ranged from 20 to 96% and were pH dependent. Aggregated and settled readily copper particles were produced by chemical reduction in PSS solution. XRD analysis identified cuprous oxide in all of the samples. Dependent of pH and polyelectrolytes, additional peaks matching those of elemental copper were identified. TGA analysis showed that solids produced from PSS and PAA systems contained no polyelectrolytes while solid collected from PEI system contained 32% of polyelectrolyte.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Polyelectrolytes with different functional groups and MW were applied in PEUF. </LI> <LI> Effects of polyelectrolytes and pH on the reduction of copper were studied. </LI> <LI> Both Cu<SUB>2</SUB>O and Cu<SUP>0</SUP> were identified by XRD analysis of solids obtained. </LI> </UL> </P>

Mechanism of conjugated polyelectrolytes for high-performance organic photovoltaics

임경근,박성민,우한영,이태우 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

In this research, we study for efficient charge extraction via electrode interfacial layers for high performance vertical and lateral organic photovoltaics(OPVs). We demonstrate that the photo-current and the power conversion efficiency of organic photovoltaic cells OPVs can be maximized by the oriented interfacial dipoles within the water soluble conjugated polyelectrolytes (CPE) layer. We synthesized cationic and anionic conjugated polyelectrolytes and then we employed them as an electron extraction layer in polymer photovoltaic cells. In contrast to the conventional belief, both the anionic and cationic CPE layers improved the electron injection and extraction at the cathode interface, which leads to highly efficient OPVs irrespective of the ionic groups of polyelectrolytes. Therefore, we investigated the role of the conjugated polyelectrolytes as the charge extraction layer by using surface photoelectron spectroscopy. We applied external electric field on the device which employ CPE interfacial layer to make that CPE interfacial layer has a net internal electric field without external bias.

초 고농도 Ag 나노 졸의 입자크기 제어가 잉크 점성거동에 미치는 영향

송해천,남산,이병석,최영민,류병환,Song, Hae-Chon,Nham, Sahn,Lee, Byong-Seok,Choi, Young-Min,Ryu, Beyong-Hwan 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.1

The rheological properties of highly concentrated Ag nano sol depending on particle size were studied. The Ag nano sol was prepared by reducing the Ag ion in aqueous solution. The size of Ag nano particle was controlled by two steps of nucleation and growth, and the thickness of adsorption layer was varied by molecular weight of polyelectrolytes. The polyelectrolytes acted as not only ionic complex agent in ionic state and but also dispersant after formation of Ag nano sol. The effective volume was controlled by combination of varying the molecular weight of polyelectrolytes and the size Ag nano sol. The particle size and the viscosity of nano sol were characterized by particle size analyzer, HR-TEM and cone & plate viscometer. It was found that the 10 nm and 40 nm-sized Ag nano sols were prepared by controlling the nucleation and growth steps, respectively. Finally, we could prepare highly concentrated Ag nano sol over 50 wt%.

Polyelectrolyte-grafted Ti₃C₂-MXenes stable in extreme salinity aquatic conditions for remediation of contaminated subsurface environments

임세형,박현수,김진형,양지원,곽채수,김지은,유승영,이주형 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

MXenes are recently gaining significant attention for numerous environmental applications owing to their superior hydrophilicity and unique surface functionalities. However, the use of MXenes for in-situ remediation of contaminated subsurface aquatic environments has not been considered yet. For effective in-situ remediation, it is of primary importance to maintain colloidal stability in harsh subsurface environments. Herein, Ti3C2-MXenes covalently grafted with polyelectrolytes (PEs), MXene-g-PEs, are developed by employing either anionic or zwitterionic PEs. Both MXene-g-PEs have sufficient colloidal stability against the immediate and irreversible aggregation observed for the pristine MXenes in API brines. The MXenes-g-(zwitterionic) PEs show long-term colloidal stability over 6 months in API brine with extreme salinity and little adsorption against α-alumina surfaces. The results suggest a high potential usefulness of the MXene-g-PEs in various subsurface applications.

양친매성 고분자전해질 도입을 통한 리포좀의 안정도 증진에 관한 연구

조은철 ( Eun Chul Cho ),임형준 ( Hyung Jun Lim ),김준오 ( Junoh Kim ),장이섭 ( Ih Seop Chang ) 대한화장품학회 2007 대한화장품학회지 Vol.33 No.1

일반적으로 cyclodextrin (CD)은 liposome의 구조를 불안정하게 만드는 것으로 알려져 있다. 본 연구에서는 양친매성 고분자전해질을 리포좀에 도입하여 CD에 대한 리포좀의 안정도를 증진시키는 연구를 수행하였다. Transmission electron microscopy와 photocorrelation spectroscopy 결과들로부터 β-CD (βCD)와 hydroxypropyl-βCD (HP β CD)를 함유하는 리포좀에 고분자가 도입되었을 때 CD를 함유하는 phosphatidylcholine (PC)-cholesterol (Chol) 리포좀보다 우수한 구조적 안정성을 나타내었다. 또한, rhaponticin (Rh)을 HP β CD에 포접시키고 이를 함유하는 PC-Chol 리포좀과 고분자가 도입된 리포좀의 안정도를 비교해 보았을 경우도 마찬가지로 고분자가 도입된 리포좀이 월등히 향상된 구조적인 안정성을 나타내는 것을 확인하였다. 이와 더불어 guinea pig의 피부조직을 사용하고 franz-cell을 통한 in vitro 피부흡수실험을 수행한 결과, HP β CD에 의해 가용화된 Rh의 피부흡수가 고분자가 도입된 리포좀에 의해 증진됨을 확인할 수 있었다. 상기 결과들은 양친매성 고분자 전해질의 도입에 따라 CD에 의해 가용화된 특정한 활성성분을 함유하는 리포좀의 구조적인 안정성을 효과적으로 증진시킬 수 있음을 확인시켜 주었으며, 이렇게 향상된 리포좀의 구조적인 안정성을 통해 약물전달시스템 측면에서 많은 응용이 가능할 것으로 생각된다. It has been generally known that liposomes become unstable when they contain cyclodextrins (CDs). Our present studies demonstrate that these liposomes can be stable by association of amphiphilic polyelectrolytes. Transmission electron microscopy and photocorrelation spectroscopy results showed that polymer-associated liposomes containing CDs (β-CD(βCD) and hydroxypropyl-βCD (HP β CD)) were more stable than phosphatidylcholine (PC)-cholesterol (Chol) liposomes containing these CDs. We also compared the stability of PC-Chol liposomes with polymer-associated liposomes containing HP β CD complexed with water-insoluble drug, rhaponticin (Rh). Two liposomes were relatively stable when HP β CD did not contain Rh, but Rh-HP β CD complexes triggered the disruption of PC-Chol liposomes. In contrast, polymer-associated Liposomes containing Rh-HP β CD complexes maintained its stability over 6 months. The skin permeation test demonstrated that drugs solubilized by CDs were delivered better into the skin of guinea pig by using polymer-associated liposomes than by using PC-Chol liposomes. Above results showed that polymer-associated liposomes gave an effective way to stabilize the liposomes containing drug-loaded CDs, which gives an application of liposomes in drug delivery systems.

Scalable Synthesis of Chestnut- Bur-like Magnetic Capsules Loaded with Size-Controlled Mono- or Bimetallic Cores

Choi, W. S.,Koo, H. Y.,Kim, D.-Y. WILEY-VCH Verlag 2007 Advanced Materials Vol.19 No.3

<B>Graphic Abstract</B> <P>A scalable synthesis of core/shell capsules by the heat treatment of polyelectrolyte-multilayer-particle reactors, in which metal nanoparticles are embedded (see figure), is demonstrated. Using this method, it is possible to prepare a wide variety of core/shell structures from a variety of materials, and to control the size, dispersity, and core composition of mono- or bimetallic core particles. <img src='wiley_img/09359648-2007-19-3-ADMA200601508-content.gif' alt='wiley_img/09359648-2007-19-3-ADMA200601508-content'> </P>

회수 가능한 고분자전해질 촉매를 이용한 폴리에틸렌테레프탈레이트의 해중합

김용수(Yong su Kim),김형준(Hyeong Jun Kim) 한국환경에너지공학회 2023 한국열환경공학회 학술대회지 Vol.2023 No.2

Glycolysis has been considered one of the most promising pathways for converting poly(ethylene terephthalate) into monomeric feedstock- bis(2-hydroxyethyl) terephthalate (BHET}-which can be used as a starting material to produce virgin PET. In this process, metal-salts, such as zinc acetate, are generally used as a catalyst for the glycolysis of PET. However, these metal-based salt catalysts often suffer from low thermal stability at elevated temperature for the glycolysis reaction. Moreover, traces of metal salts can be included in the final products, critically reducing the quality of the chemically recycled PET. To address tills, many of previous studies have used organic salts including ionic liquids as an efficient catalyst for the glycolysis. Here, we present a new organic catalyst based on polyelectrolytes which offer excellent thermal stability and ease of separation and reusability. Among various types of polyelectrolytes, polyanions such as poly(sodium styrene sulfonate)(PSSNa), sodium polyacrylate(PANa), poly[l-ethyl-3-methyl imidazolium (3-sulfopropyl) acrylate](PES) shows high depolymerization yields of PET, comparable to that of metal-based catalysts while polycations shows significantly lower efficiency. We speculate that for the glycolysis of PET, cations play a crucial role in initiating the glycolysis process while the covalently bounded cations in polycation electrolytes appear to impede this initiation step.

Solution-processed pH-neutral conjugated polyelectrolytes with one-atom variation (O, S, Se) as a novel hole-collecting layer in organic photovoltaics

Choi, Min-Hee,Lee, Eui Jin,Han, Jae Pil,Moon, Doo Kyung Elsevier 2016 Solar energy materials and solar cells Vol.155 No.-

<P><B>Abstract</B></P> <P>We present pH-neutral hole transporting layers processed from a solution at room temperature for organic photovoltaics (OPVs). Three new conductive conjugated polyelectrolytes (CPEs), identified as PFF, PFT and PFSe, containing aromatic five-membered heterocyclic compounds (furan, thiophene, and selenophene, respectively), are designed and synthesized using the Stille-coupling reaction. These polymers dissolve in water/alcohol as they are comprised of a conjugated backbone with hydrophilic side chains of sodium butane sulfonates. The CPEs with heterocyclic rings having stronger dipole moments decrease the work function of ITO electrodes and the surface potential between the active layer and hole-transporting layer (HTL) effectively. The device with PFSe as a HTL exhibits the best performance (7.2%), with J<SUB>SC</SUB> of 14.4mAcm<SUP>−2</SUP>, V<SUB>OC</SUB> of 0.677V and FF of 69.0%. The device also exhibits improvements in air stability under room temperature due to its neutral nature. Also, 70% of its initial power conversion efficiency (PCE) is maintained upon exposure to ambient air for ∼480h, whereas the initial PCE with PEDOT:PSS decreases by more than 50%. Our results indicate that it is possible to improve the performance of OPVs using pH-neutral CPEs as efficient HTLs. We determine the way of molecular design is used to decrease the energy barrier using a heteroatom with a large dipole moment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Conjugated polyelectrolytes with different heteroatoms have modified dipole moments. </LI> <LI> Work function and surface potential of ITO are changed by the dipole moments of CPEs. </LI> <LI> Strong dipole moments lead to an increase in Jsc and air stability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Intercalation of conjugated polyelectrolytes in layered titanate nanosheets for enhancement in photocatalytic activity

Hong, Seong Won,Kim, Aran,Choi, Joon Hyun,Jung, Hyun,Park, Jin Kuen Elsevier 2019 Journal of solid state chemistry Vol.269 No.-

<P><B>Abstract</B></P> <P>Cationic π-conjugated polyelectrolytes (CPEs) were successfully intercalated into layered titanate (TiO<SUB>2</SUB>), while exfoliated layered titanates were reassembled into lamellar structures. The resulting composites showed significantly enhanced visible light absorbance and enhanced photocatalytic activity with respect to layered titanate, which was proven by the photodegradation of methylene blue in aqueous media under irradiation by visible light. Notably, some amount of tetrabutylammonium (TBA) used for the delamination of a layered titanate could be co-intercalated with CPEs, and the residual TBA could be removed via continuously repeating the intercalation process, maintaining the spatial arrangement and content of CPEs in the confined area of layered titanates. However, with the presence of TBA, the hybrid demonstrated greater performance in the photodegradation of methylene blue at any given period of time and almost complete degradation of such dye within 8 min. The significant difference in photocatalytic efficiency with or without TBA suggested that the TBA effectively reduced the surface energy at the interface between the organic components and aqueous medium, which was evidenced by the dispersity assessment of hybrids with or without TBA.</P> <P><B>Graphical abstract</B></P> <P>Cationic π-conjugated polyelectrolytes (CPEs) were successfully intercalated into layered titanate (TiO<SUB>2</SUB>). The resulting composites showed significantly enhanced photocatalytic activity which was proven by the photodegradation of methylene blue in aqueous media under irradiation by visible light. Notably, with the presence of TBA, the hybrid demonstrated greater performance in the photodegradation of methylene blue at any given period of time and almost complete degradation of such dye within 8 min.</P> <P>[DISPLAY OMISSION]</P>

Cationic Conjugated Polyelectrolytes with Molecular Spacers for Efficient Fluorescence Energy Transfer to Dye-Labeled DNA

Woo, H. Y.,Vak, D.,Korystov, D.,Mikhailovsky, A.,Bazan, G. C.,Kim, D.-Y. WILEY-VCH Verlag 2007 Advanced Functional Materials Vol.17 No.2

<P>Two water-soluble conjugated polyelectrolytes, poly(9,9′-bis(6-N,N,N-trimethylammoniumhexyl)fluorene-alt-1,4-(2,5-bis(6-N,N,N-trimethylammoniumhexyloxy))phenylene) tetrabromide (P1i) and poly((10,10′-bis(6-N,N,N-trimethylammoniumhexyl)-10H-spiro(anthracene-9,9′-fluorene))-alt-1,4-(2,5-bis(6-N,N,N-trimethylammoniumhexyloxy))phenylene) tetrabromide (P2i) are synthesized, characterized, and used in fluorescence resonance energy transfer (FRET) experiments with fluorescein-labeled single-stranded DNA (ssDNA-Fl). P1i and P2i have nearly identical &pgr;-conjugated backbones, as determined by cyclic voltammetry and UV-vis spectroscopy. The main structural difference is the presence of an anthracenyl substituent, orthogonal to the main chain in each of the P2i repeat units, which increases the average interchain separation in aggregated phases. It is possible to observe emission from ssDNA-Fl via FRET upon excitation of P2i. Fluorescein is not emissive within the ssDNA-Fl/P1i electrostatic complex, suggesting Fl emission quenching through photoinduced charge transfer (PCT). We propose that the presence of the anthracenyl “molecular bumper” in P2i increases the distance between optical partners, which decreases PCT more acutely relative to FRET.</P> <B>Graphic Abstract</B> <P>Two cationic conjugated polyelectrolytes (CCPs, see figure) with similar optical/electronic properties but different molecular structures act as fluorescence resonance energy transfer (FRET) donors to fluorescein (FL)-labeled single-stranded DNA. Comparison of their efficiencies of energy transfer indicates that backbone modification with “molecular bumpers” fine-tunes the competition between FRET and photoinduced charge-transfer (PCT) mechanisms. <img src='wiley_img/1616301X-2007-17-2-ADFM200600093-content.gif' alt='wiley_img/1616301X-2007-17-2-ADFM200600093-content'> </P>