• 공업화학
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• 제33권2호
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• pp.210-215
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• 2022

표면의 전하 특성이 다른 두 가지 리그닌을 사용하여 이전 연구에서 제시된 간단한 방법인 용액상 화학적 중합을 이용하여 폴리피롤@리그닌(PPy@lignin) 및 폴리피롤@리그노설포네이트(PPy@lignosulfonate) 복합소재를 제조하였다. 폴리피롤은 두 가지 리그닌 표면에서 각각 성공적으로 중합되었으며, 얻어진 복합소재들은 주사전자현미경, 순환전압 전류법, 임피던스(impedance) 분석법 등을 이용하여 분석하였다. 이러한 결과들을 바탕으로, 리그닌의 종류가 달라도 복합재료들은 성공적으로 제조되는 것을 알 수 있었으며, 전기적 특성도 일정하게 유지되는 것으로 나타났다. 다만, 개별 리그닌의 표면 특성 차이로 나타나는 물성 차이가 존재함을 임피던스 분석으로 판단할 수 있었다. 나아가, 두 가지 복합소재들을 아가로즈(agarose) 젤(gel)에 투입하여 전도성 젤을 형성하고 이 젤들의 특성들을 역시 순환전압전류법으로 살펴보았으며, 전기전도도를 측정하여 제시하였다. 리그닌의 전기절연성에도 불구하고 전도성 젤이 전기전도도를 포함한 전기적 특성을 유지하는 것을 알 수 있었다. 이는 전도성 젤의 활용이 가능하다는 점을 의미한다.

• Journal of the Korean Wood Science and Technology
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• 제45권6호
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• pp.703-719
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• 2017

Miscanthus had a higher lignin content (19.5 wt%) and carbohydrate (67.6 wt%) than other herbaceous crops, resulting in higher pellet strength and positive effect on combustion. However, miscanthus also contains a high amount of hydrophobic waxes on its outer surface, cuticula, which limits the pellet quality. The glass transition of lignin and cuticula were related to forming inter-particle bonding, which determined mechanical properties of pellet. To determine the effects of surface waxes, both on the pelletizing process and the pellet strength were compared with raw and extracted samples through solvent extraction. In addition, to clarify the relationship between pellet process parameters and bonding mechanisms, the particle size and temperature are varied while maintaining the moisture content of the materials and the die pressure at constant values. Furthermore, kraft lignin was employed to determine the effect of kraft lignin as an additive in the pellets. As results, the removal of cuticula through ethanol extractions improved the mechanical properties of the pellet by the formation of strong inter-particle interactions. Interestingly, the presence of lignin in miscanthus improves its mechanical properties and decreases friction against the inner die at temperatures above the glass transition temperature ($T_g$) of lignin. Consequently, it could found that the use of kraft lignin as an additive in pellet reduced friction in the inner die upon reaching its glass transition temperature.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.1
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• pp.51-59
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• 2006

The surface of various mechanical pulp fibres including thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), and alkaline peroxide mechanical pulp (APMP) fibres, were characterized using SEM, AFM, and XPS. With SEM and AFM, middle lamella material was observed to be non-fibrillar, patch-like, while fibre secondary wall was observed to have a microfibrillar structure. It was found that after the first-stage refiner, lignin-rich middle lamella remainders are present on the fibre surface of all three pulps, although most of the fibre surfaces expose microfibrillar structure. After the final-stage refining, large amounts of granules are present on the TMP fibre surface. In contrast, most middle lamella remainders remain on the surface of CTMP fibres after final stage refining and even after peroxide bleaching. XPS results have confirmed that the non-fibrillar surface material is the lignin-rich middle lamella remainder., and the remainders of middle lamella contribute to the high surface lignin concentration.

• 청정기술
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• 제23권4호
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• pp.408-412
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• 2017

Pigment red 53:1 is a dye used in various products as a component of the inks, suspected of being carcinogenic. Thus, the environmental and occupational issues related to it are important. The enzyme-based approach with reusability has advantages to consume less energy and generate less harsh side- products compared to the conventional strategies including separations, microbe, and electrochemical treatment. The degradation of Pigment red 53:1 by the lignin peroxidase immobilized on the surface of magnetic particles has been studied. The immobilization of the peroxidase was conducted on magnetic particle surface with the treatment of polyethyleneimine, glutaraldehyde, and the peroxidase, in sequence. The immobilization was confirmed using X-ray photon spectroscopy. The absorbance peak of the pigment was monitored at 495 nm of UV/Vis spectrum with respect to time to calculate the catalytic activities of the pigment for the immobilized lignin peroxidase. For the comparison, the absorbance of the lignin peroxidase free in solution was also monitored. The catalytic rate constant values for the free lignin peroxidases and the immobilized those were 0.51 and $0.34min^{-1}$, respectively. The reusable activity for the immobilized lignin peroxidase was kept to 92% after 10 cycles. The stabilities for heat and storage were also investigated for both cases.

• Carbon letters
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• 제22권
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• pp.81-88
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• 2017

In the present study, biomass-based lignin was extracted from industrial waste black liquor and the extracted lignin was characterized by means of attenuated total reflectance-Fourier transform infrared spectroscopy and $^1H-nuclear$ magnetic resonance spectroscopy. The extracted lignin was carbonized at different temperatures and then activated with steam at $850^{\circ}C$. The extracted lignin in powder state was transformed into a bulky carbonized lignin due to possible fusion between the lignin particles occurring upon carbonization. The carbonized and then pulverized lignin exhibits brittle surfaces, the increased thermal stability, and the carbon assay with increasing the carbonization temperature. The scanning electron microscopic images and the Brunauer-Emmett-Teller result indicate that the steam-activated carbon has the specific surface area of $1718m^2/g$, which is markedly greater than the carbonized lignin. This study reveals that biomass-based activated carbon with highly porous structure can be produced from costless black liquor via steam-activation process.

• Journal of Electrochemical Science and Technology
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• 제15권1호
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• pp.111-131
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• 2024

Lignin-derived porous carbon has been identified as a versatile electrode material for supercapacitors (SCs) in energy storage systems (ESSs) owing to their intrinsic advantages including good electrical conductivity, low cost, high thermal and chemical stability, and high porosity, which stem from high surface, appropriate pore distribution, tailored morphologies, heterostructures, and diverse derivates. In this review, to provide a fundamental understanding of the properties of lignin, we first summarize the origin, historical development, and basic physicochemical properties. Next, we describe essential strategies for the preparation of lignin-derived porous carbon electrode materials and then highlight the latest advances in the utilization of lignin-derived porous carbon materials as advanced electrode materials. Finally, we provide some of our own insights into the major challenges and prospective research directions of lignin-derived porous carbon materials for supercapacitors. We believe that this review will provide general guidance for the design of next-generation electrode materials for supercapacitors.

• Journal of the Korean Wood Science and Technology
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• 제49권4호
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• pp.299-314
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• 2021

본 연구에서는 리그닌 기반 다공성 탄소(lignin-based porous carbon; LBPC)를 수산화칼륨(KOH)으로 활성화할 때 온도가 비표면적과 전기화학적 특성에 미치는 영향을 알아보았다. 리그닌과 acrylonitrile을 그라프트 중합으로 합성한 리그닌-polyacrylonitrile (PAN) 공중합체를 전구체로 하여 LBPC를 제조한 후 LBPC를 KOH로 600, 700, 800, 900℃에서 활성화하여 활성화 처리한 LBPC (KA-LBPC-6, 7, 8, 9)를 제조하였다. KA-LBPC의 표면 특성을 알아보기 위해 주사전자현미경으로 관찰하였으며, 비표면적 분석을 통해 기공 특성을 파악하였다. 전기화학적 특성은 3전극 시스템으로 분석하였다. 실험 결과 SEM 사진상에서 활성화 처리에 의한 미세기공 형성을 관찰하였다. KA-LBPC-7의 비표면적은 2480.1 m²/g, 미세기공 부피는 0.64 cm³/g, 중기공 부피는 0.76 cm³/g으로 KA-LBPC 중에서 가장 좋은 기공 특성을 보였다. 전기화학적 특성 역시 2 mV/s의 주사속도에서 비정전용량이 151.3 F/g이었던 KA-LBPC-7이 가장 좋은 것으로 나타났다.

• 대한환경공학회지
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• 제22권1호
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• pp.133-139
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• 2000

리그닌의 열분해반응 후 발생하는 잔류고형물을 활용해보고자 $ZnCl_2$로 활성화하여 활성탄을 제조하였다. 공정변수로 설정한 활성화 온도, 활성화 시간 및 활성화제의 첨가량 등이 활성탄의 세공구조와 비표면적에 미치는 영향을 조사하여 최적 활성화 조건을 구하였다. 리그닌의 열분해 잔류고형물에 활성화제인 염화아연을 300wt% 첨가한 것을 질소분위기에서 $1000^{\circ}C$로 1시간 동안 활성화시켰을 때 비교적 높은 비표면적과 흡착능을 가지면서 세공구조가 잘 발달된 활성탄을 제조할 수 있었다.

• Journal of the Korean Wood Science and Technology
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• 제51권5호
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• pp.321-333
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• 2023

In this study, lignin, a lignocellulosic biomass, was chemically modified to produce polyethyleneimine-grafted lignin (PKL) with maximum hexavalent chromium [Cr(VI)] adsorption capacity. Changes in the physicochemical properties due to the cationization of lignin were confirmed through elemental analysis, Fourier transform infrared spectroscopy, and moisture stability evaluation. Alginate (Alg) beads containing PKL (Alg/PKL) were prepared by incorporating cationic lignin into the Alg matrix to apply the prepared PKL in a batch-type water treatment process. The optimal Alg/lignin mixing ratio was selected to increase the Cr(VI) adsorption capacity and minimize lignin elution from the aqueous system. The selected Alg/PKL beads exhibited an excellent Cr(VI) removal capacity of 478.98 mg/g. Isothermal adsorption and thermodynamic analysis revealed that the Cr(VI) removal behavior of the Alg/PKL beads was similar to that of heterogeneous chemical adsorption. In addition, the bulk adsorbent material in the form of beads exhibited adsorption behavior in three stages: surface adsorption, diffusion, and equilibrium.

• Journal of the Korean Wood Science and Technology
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• 제52권2호
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• pp.101-117
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• 2024

The conversion characteristics of the major components of Liriodendron tulipifera were investigated during acid-catalyzed organosolv pretreatment. Glucan in L. tulipifera was slowly hydrolyzed, whereas xylan was rapidly hydrolyzed. Simultaneous hydrolysis and degradation of xylan and lignin occurred; however, after complete hydrolysis of xylan at higher temperatures, lignin remained and was not completely degraded or solubilized. These conversion characteristics influence the structural properties of glucan in L. tulipifera. Critical hydrolysis of the crystalline regions in glucan occurred along with rapid hydrolysis of the amorphous regions in xylan and lignin. Breakdown of internal lignin and xylan bonds, along with solubilization of lignin, causes destruction of the lignin-carbohydrate complex. Over a temperature of 160℃, the lignin that remained was coalesced, migrated, and re-deposited on the surface of pretreated solid residue, resulting in a drastic increase in the number and content of lignin droplets. From the results, the characteristic conversions of each constituent and the changes in the structural properties in L. tulipifera effectively improved enzymatic hydrolysis in the range of 140℃-150℃. Therefore, it can be concluded that significant changes in the biomass recalcitrance of L. tulipifera occurred during organosolv pretreatment.