Factors affecting the sorption of halogenated phenols onto polymer/biomass-derived biochar: Effects of pH, hydrophobicity, and deprotonation

Oh, Seok-Young,Seo, Yong-Deuk Elsevier 2019 Journal of environmental management Vol.232 No.-

<P><B>Abstract</B></P> <P>High-performance biochar synthesized via co-pyrolysis of a polymer and rice straw (RS) was evaluated as a sorbent for ionizable halogenated phenols. Compared with RS-derived biochar, the sorption of 2,4-dichlorophenol (DCP), 2,4-dibromophenol (DBP), and 2,4-difluorophenol (DFP) onto polymer/RS-derived biochar was significantly enhanced by the properties of biochar changing due to polymer residues. According to Langmuir sorption isotherm model maximum sorption capacities for DCP, DBP, and DFP were 25.5–27.8, 22.1–26.5, and 11.5–13.3 mg/g, respectively, 3–5 times higher than those of RS-derived biochar. The removal of the polymer residues and increasing aromaticity of polymer/RS-derived biochar at elevated pyrolysis temperatures affected the sorption capacity of halogenated phenols. The surface charge of biochar and deprotonation of the halogenated phenols according to the solution pH were other factors responsible for sorption onto polymer/RS-derived biochar. Competition with other halogenated phenols, Zn<SUP>2+</SUP>, and Cu<SUP>2+</SUP> implied that similar sorption mechanisms existed and that surface complexation and electron donor-acceptor interactions were involved in sorption onto polymer/RS-derived biochar. Our results suggest that co-disposal of thermoplastic and biomass wastes through pyrolysis may be an effective option to produce high-performance upgraded biochar as a sorbent for various types of contaminants.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Polymer/rice straw-derived biochar enhances the sorption of halogenated phenols. </LI> <LI> Affecting factors are polymer residues, surface charge, and deprotonation of phenols. </LI> <LI> Surface complexation and electron donor-acceptor interactions are also responsible. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

1LE-5 Study on Carbon Dioxide Assisted Pyrolysis of Polymers

권일한,이제찬,최동호,이태우 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

This study placed a great emphasis on the mechanistic understanding of carbon dioxide in the thermal degradation of various polymers. To this end, the thermal degradation of polymer in the presence of carbon dioxide was thermo-gravimetrically investigated. To expand the experimental knowledge, a series of batch and continuous pyrolysis experiments with a tubular reactor and a drop tube reactor was conducted. All experimental findings strongly suggested the genuine roles of carbon dioxide in pyrolysis of polymers. For instance, carbon dioxide was effectively served as a radical scavenger, thereby resulting in a substance reduction of tar formation as well as physico-chemical properties of pyrogenic products during the pyrolysis process of polymers.

Polymer/biomass-derived biochar for use as a sorbent and electron transfer mediator in environmental applications

Oh, S.Y.,Seo, Y.D. Elsevier Applied Science 2016 Bioresource technology Vol.218 No.-

Co-pyrolysis of polymer and biomass wastes was investigated as a novel method for waste treatment and synthesis of enhanced biochar. Co-pyrolysis of rice straw (RS) with polypropylene (PP), polyethylene (PE) or polystyrene (PS) increased the carbon content, cation exchange capacity (CEC), surface area and pH of the biochar. As a result, the sorption of 2,4-dinitrotoluene (DNT) and Pb to polymer/RS-derived biochar was markedly enhanced. The increased aromaticity and hydrophobicity may be responsible for enhancing the DNT sorption to the polymer/RS-derived biochar. In contrast, increasing CEC, higher pH, and the newly developed surface area may account for the enhancement in Pb sorption. The addition of polymer to RS did not significantly change the catalytic role of biochar during the reduction of DNT by dithiothreitol. Our results suggest that co-pyrolysis of RS and polymer can improve the biochar properties to enhance the sorption of DNT and Pb.

Advancements in Polymer-Filler Derived Ceramics

Peter Greil 한국세라믹학회 2012 한국세라믹학회지 Vol.49 No.4

Microstructure tailoring of filler loaded preceramic polymer systems offers a high potential for property improvement of Sibased ceramics and composites. Advancements in manufacturing of bulk materials by controlling microstructure evolution during thermal induced polymer-ceramic transforma-tion and polymer-filler reactions will be presented. Rate controlled pyrolysis, multilayer gradient laminate design and surface modification by gas solid reaction are demonstrated to yield ceramic components of high fractional density and superior mechanical properties. Emerging fields of applications are presented.

Advancements in Polymer-Filler Derived Ceramics

Greil, Peter The Korean Ceramic Society 2012 한국세라믹학회지 Vol.49 No.4

Microstructure tailoring of filler loaded preceramic polymer systems offers a high potential for property improvement of Si-based ceramics and composites. Advancements in manufacturing of bulk materials by controlling microstructure evolution during thermal induced polymer-ceramic transforma-tion and polymer-filler reactions will be presented. Rate controlled pyrolysis, multilayer gradient laminate design and surface modification by gas solid reaction are demonstrated to yield ceramic components of high fractional density and superior mechanical properties. Emerging fields of applications are presented.

Influence of Nitrogen Moieties on CO2 Capture by Polyaminal-Based Porous Carbon

Adeela Rehman,박수진 한국고분자학회 2017 Macromolecular Research Vol.25 No.10

The escalating level of CO2 in the atmosphere is the chief contributor to global warming and climate change. Existing technologies for post-combustion CO2 scavenging and air separation are inefficient and energy intensive. The cost-effective fabrication of adsorbents with efficient CO2 capture ability is the ultimate goal of the present work. Hence, a melamine-based porous organic polymer (MBPP) was synthesized by single-step condensation of isophthalaldehyde and 2,4,6-triamino- 1,3,5-triazine using Schiff base chemistry. Pyrolysis of the as-prepared polymer at 800 oC produced nitrogen-rich porous carbon (NRC), which exhibited greater adsorption potential than the initial polymer. The fabricated materials were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, thermal-gravimetric analysis, elemental analysis, textural analysis, and CO2 capture measurements. The moderately high surface area 445m2·g-1 was exhibited by NRC with the CO2 capture of 128.37 mg·g-1 (2.91mmol·g-1) at 273 K and 1 bar.

Synthesis and Functionalization of Ynone-Based Tubular Microporous Polymer Networks and Their Carbonized Products for CO2 Capture

이정민,장지영 한국고분자학회 2019 Macromolecular Research Vol.27 No.10

Ynone-based microporous polymer networks (YMPNs) were synthesized by the reaction of aromatic dicarboxylic acid chloride and alkyne groups under Sonogashira cross-coupling reaction conditions. As the reaction proceeded in a mixture of toluene and triethylamine (TEA), tubular precipitates formed rapidly. The microscopic and XRD studies showed that the precipitates had a core-shell structure with a rod-shaped triethylammonium chloride (TEA-HCl) crystalline core and a polymeric shell. The core was removed by washing with methanol to provide a hollow polymeric tube. The TEA-HCl rod formed in situ during the cross-coupling reaction and served as a template in forming the tubular morphology. YMPNs could be modified with ease because of the presence of highly reactive ynone groups. YMPNs were functionalized with ethylenediamine by the Michael-type addition reaction. The amino group functionalized YMPNs were used as precursors of nitrogen-doped porous carbons. The pyrolysis of the polymers at 800 oC produced microporous carbon materials without the activation process. The carbon materials showed significantly enhanced Brunauer-Emmett-Teller (BET) surface areas and CO2 uptake capacities compared to their precursor polymers.

Electrochemical properties of stacked-nanoflake Li4Ti5O12 spinel synthesized by a polymer-pyrolysis method

Xiaoming Zhu,Xiaoyu Jiang,Haiyan Lu,Xinping Ai,Hanxi Yang,Yuliang Cao 한국물리학회 2014 Current Applied Physics Vol.14 No.4

Stacked-nanoflake Li4Ti5O12 spinel was synthesized via the pyrolysis of a LieTi copolymeric precursor formed by in situ polymerization of LiOH and [Ti(OC4H9)4] and acrylic acid. XRD and SEM characterization shows that the powders calcined at 700 C for 3 h was well-crystallized particles with submicron diameter. Chargeedischarge measurement showed the Li4Ti5O12 electrode had displayed excellent rate capability and delivered reversible capacity of 171, 158, 148, 138 and 99 mAh g1 at rates of 0.1C, 0.5C, 1C, 2C and 4C, respectively. The test electrode also showed excellent cyclability as the capacity retains 96.1% after 60 cycles between 0.5 and 2.5 V.

고분자 열분해 방법으로 제조된 TiN-Ti₅Si₃ 세라믹 복합체의 고온 산화 거동

김범섭,김득중,이동복,Kim, Beom-Seob,Kim, Deug-Joong,Lee, Dong-Bok 한국세라믹학회 2006 한국세라믹학회지 Vol.43 No.8

A new $TiN-Ti_5Si_3$ bulk composite was synthesized from preceramic, inorganic polymer (methylpolysilsesquioxane) and $TiH_2$ filler powders via polymer pyrolysis. Using this process, ceramics with high melting points can be produced relatively easily to a near net shape. The $TiN-Ti_5Si_3$ composite oxidized slowly during heating to $1000^{\circ}C$. During heating at the temperatures of at 700 and $800^{\circ}C$, TiN oxidized to Rutile-$TiO_2$ whereas $Ti_5Si_3$ resisted to oxidation. The oxide scale formed consisted primarily of $TiO_2$ containing $Ti_5Si_3$.

SiCf/SiC 복합체 보호막 금속피복관의 열충격 거동 분석

이동희 ( Dong Hee Lee ),김원주 ( Weon Ju Kim ),박지연 ( Ji Yeon Park ),김대종 ( Dae Jong Kim ),이현근 ( Hyeon Geon Lee ),박광헌 ( Kwang Heon Park ) 한국복합재료학회 2016 Composites research Vol.29 No.1

원자력발전소에서 사용되고 있는 핵연료 피복관은 핵분열 생성물들의 외부 유출을 방지하기 위해 고온고압의 냉각수 분위기에서 우수한 산화저항성을 가져야 한다. 그러나 후쿠시마 원전사고의 LOCA(Loss-Of-Coolant-Accident)와 같은 중대사고에서 핵연료의 피복관과 수증기 사이의 격렬한 반응으로 인해 급격한 고온산화를 동반한 다량의 수소발생으로 수소폭발을 방지하기 위한 핵연료의 개발이 요구되고 있다. 이에 따라 핵연료 피복관의 안전성 향상을 위해 내방사선성이 우수하며 높은 강도와 산화, 부식에 대한 내화학적 안정성 및 우수한 열전도도의 특성을 갖는 SiC와 같은 구조용 세라믹스가 활발히 연구되고 있다. SiCf/SiC 복합체 보호막 금속 피복관은 지르코늄 피복관 튜브에 SiC 섬유를 필라멘트 와인딩 한 후 Polycarbosilane을 polymer로 함침하여 기지상을 형성하는 공정을 이용하였다. 따라서 이렇게 제조한 SiCf/SiC 복합체 금속 피복관을 Drop Tube Furnace를 이용한 열충격에 따른 시편의 산화 및 미세조직을 분석하였다. Nuclear fuel cladding used in a nuclear power plant must possess superior oxidation resistance in the coolant atmosphere of high temperature/high pressure. However, as was the case for the critical LOCA (loss-of-coolant accident) accident that took place in the Fukushima disaster, there is a risk of hydrogen explosion when the nuclear fuel cladding and steam reacts dramatically to cause a rapid high-temperature oxidation accompanied by generation of a huge amount of hydrogen. Hence, an active search is ongoing for an alternative material to be used for manufacturing of nuclear fuel cladding. Studies are currently aimed at improving the safety of this cladding. In particular, ceramic-based nuclear fuel cladding, such as SiC, is receiving much attention due to the excellent radiation resistance, high strength, chemical durability against oxidation and corrosion, and excellent thermal conduction of ceramics. In the present study, cladding with SiCf/SiC protective films was fabricated using a process that forms a matrix phase by polymer impregnation of polycarbosilane (PCS) after filament-winding the SiC fiber onto an existing Zry-4 cladding tube. It is analyzed the oxidation and microstructure of the metal cladding with SiCf/SiC composite protective films using a drop tube furnace for thermal shock test.