Fly ash-derived mesoporous silica foams for CO2 capture and aqueous Nd3+ adsorption

Siqian Zhang,Seenu Ravi,이유리,안지환,안화승 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.72 No.-

A supernatant solution of the silicate species extracted after alkali fusion of the acid-treated power plantfly ash was used to prepare mesoporous silica foams (MSFS) in acidic condition, where Pluronic P123 andtrimethylbenzene (TMB) were used as the structure directing agent and swelling agent, respectively. TheMSF was impregnated with polyethyleneimine (PEI) up to 63.2 wt.%, which exhibited CO2 adsorptioncapacity of 4.7 mmol/g adsorbent at 75 C,1 bar. Additionally, the MSF after ethylenediaminetetraacetic acid(EDTA) functionalization showed the Nd3+ adsorption capacity of 117 mg/g at the optimal pH of 6, withsufficiently fast kinetics and good recyclability.

Fly ash-derived mesoporous silica foams for CO₂ capture and aqueous Nd³⁺ adsorption

Zhang, Siqian,Ravi, Seenu,Lee, Yu-Ri,Ahn, Ji-Whan,Ahn, Wha-Seung THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2019 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.72 No.-

<P><B>Abstract</B></P> <P>A supernatant solution of the silicate species extracted after alkali fusion of the acid-treated power plant fly ash was used to prepare mesoporous silica foams (MSF<SUB>S</SUB>) in acidic condition, where Pluronic P123 and trimethylbenzene (TMB) were used as the structure directing agent and swelling agent, respectively. The MSF was impregnated with polyethyleneimine (PEI) up to 63.2wt.%, which exhibited CO<SUB>2</SUB> adsorption capacity of 4.7mmol/g <SUB>adsorbent</SUB> at 75°C, 1bar. Additionally, the MSF after ethylenediaminetetraacetic acid (EDTA) functionalization showed the Nd<SUP>3+</SUP> adsorption capacity of 117mg/g at the optimal pH of 6, with sufficiently fast kinetics and good recyclability.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Sodium silicate insulating foam reinforced with acid-treated fly ash

Zhang, Siqian,Lee, Yu-Ri,Ahn, Ji-Whan,Ahn, Wha-Seung Elsevier 2018 Materials letters Vol.218 No.-

<P><B>Abstract</B></P> <P>A set of insulating foams based on sodium silicate were prepared using acid-treated fly ash as an additive. It was found that the HCl-treated fly ash was able to remove the undesirable transition/alkali metal impurities up to 74%. Furthermore, the effect of the fly ash amount and modulus (SiO<SUB>2</SUB>/Na<SUB>2</SUB>O mole ratio) on the thermal conductivity, density, and compressive strength of the product was evaluated. The insulating foam prepared using 12.5 wt% acid-treated fly ash and modulus of 1.8 exhibited a low thermal conductivity of 0.0428 W/m·K, density of 156.3 kg/m<SUP>3</SUP>, and high compressive strength of 1.12 MPa.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Insulating foams were prepared using acid-treated fly ash as an additive. </LI> <LI> Acid-treated fly ash removed harmful transition metal and alkali impurities. </LI> <LI> Acid-treated fly ash led to enhancement in physical properties of insulating foam. </LI> <LI> It had low thermal conductivity (0.0428 W/m·K) and high compressive strength (156 kg/m<SUP>3</SUP>). </LI> </UL> </P>

Pd nanoparticles on a microporous covalent triazine polymer for H₂ production via formic acid decomposition

Zhang, Siqian,Lee, Yu-Ri,Jeon, Hyo-jin,Ahn, Wha-Seung,Chung, Young-Min Elsevier 2018 Materials letters Vol.215 No.-

<P><B>Abstract</B></P> <P>A new catalyst comprising Pd nanoparticles (NPs) supported on a microporous covalent triazine-based polymer (Pd/MCTP-1) was synthesized and applied for H<SUB>2</SUB> production via formic acid decomposition under ambient conditions without additives. The catalytic activity of Pd/MCTP-1 was found to be superior to those of the recently reported highly active Pd/MOF catalysts, Pd/C, and Pd/SBA-15, which may be attributed to two factors: i) the formation of monodisperse and smaller Pd NPs on MCTP-1 and ii) the neutral pH of the reaction medium attained in the presence of Pd/MCTP-1. Pd/MCTP-1 is highly stable and its catalytic activity was maintained without losses for three recycle runs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pd nanoparticles on a microporous covalent triazine-based polymer (Pd/MCTP-1) was synthesized. </LI> <LI> The Pd/MCTP-1showed excellent catalytic activity for formic acid decomposition. </LI> <LI> The superior activity is attributed to the formation of small nanoparticles and neutral pH of the reaction medium. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Industrial Solid Waste-Based Layered Double Hydroxide Composite with Enhanced Adsorption Affinity to Congo Red, Acid Red, and Reactive Red

Zhang Siqian,Lee Jaewon,Li Bin,Zhang Tianyang,백성현,심상은 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.3

The synthesis of hierarchically porous materials from industrial solid waste as catalysts or adsorbents has attracted much attention in environmental pollution control. The present work highlights the synthesis of a series of MgFeAl layered double hydroxide (LDH) with diff erent ratios of Mg/(Fe + Al) from red mud and ferronickel slag under diff erent pH to decolorize three red dye solutions, namely, Congo red (CR), acid red (AR), and reactive red (RR). The maximum adsorption capacity (386.1 mg.g −1 ) for CR was obtained by the MgFeAl-LDH sample with Mg/(Fe + Al) mole ratio of 2 synthesized under pH 10. The optimized synthesis parameters led to a high surface area and large pore volume of MgFeAl-LDH, thereby enhancing the mass transfer of adsorbate to the active sites of the adsorbent. Further, the MgFeAl-LDH sample was also effi cient in removing AR (120.9 mg.g −1 ) and RR (114 mg.g −1 ). Moreover, the adsorption kinetics and isotherms of MgFeAl-LDH fi tted well with the pseudo-second-order and Langmuir models, respectively. The MgFeAl-LDH system developed a valuable approach to utilize industrial waste for dye removal.

EDTA-functionalized KCC-1 and KIT-6 mesoporous silicas for Nd3+ ion recovery from aqueous solutions

Seenu Ravi,Siqian Zhang,이유리,강경구,김지만,안지환,안화승 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.67 No.-

Ethylenediaminetetraacetic acid (EDTA)-functionalized KIT-6 and KCC-1 mesoporous silicas were prepared via post-synthesis grafting and examined for their ability to promote the recovery of rare earth metal ions such as Nd3+ from an aqueous medium. The obtained adsorption isotherms were fitted to the Langmuir model, which gave a maximum adsorption of Nd3+ ions of 109.8 and 96.5 mg/g for KIT-6-EDTA and KCC-1-EDTA, respectively, at 25 °C and pH 6. The adsorption kinetic profile of KIT-6 was faster than KCC-1. KIT-6 was also proved to be more stable against desorption under acidic regeneration conditions.

EDTA-functionalized KCC-1 and KIT-6 mesoporous silicas for Nd³⁺ ion recovery from aqueous solutions

Ravi, Seenu,Zhang, Siqian,Lee, Yu-Ri,Kang, Kyoung-Ku,Kim, Ji-Man,Ahn, Ji-Whan,Ahn, Wha-Seung Elsevier 2018 Journal of industrial and engineering chemistry Vol.67 No.-

<P><B>Abstract</B></P> <P>Ethylenediaminetetraacetic acid (EDTA)-functionalized KIT-6 and KCC-1 mesoporous silicas were prepared via post-synthesis grafting and examined for their ability to promote the recovery of rare earth metal ions such as Nd<SUP>3+</SUP> from an aqueous medium. The obtained adsorption isotherms were fitted to the Langmuir model, which gave a maximum adsorption of Nd<SUP>3+</SUP> ions of 109.8 and 96.5mg/g for KIT-6-EDTA and KCC-1-EDTA, respectively, at 25°C and pH 6. The adsorption kinetic profile of KIT-6 was faster than KCC-1. KIT-6 was also proved to be more stable against desorption under acidic regeneration conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ethylenediaminetetraacetic acid (EDTA) grafted KIT-6 and KCC-1 was prepared. </LI> <LI> KIT-6-EDTA showed high adsorption capacities for Nd<SUP>3+</SUP> ions in water. </LI> <LI> Adsorption equilibrium, isotherm, and kinetics were investigated. </LI> <LI> KIT-6-EDTA reused for 5 cycles without deterioration in adsorption capacities. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Amine-silica composites for CO2 capture: A short review

Chen, Chao,Zhang, Siqian,Row, Kyung Ho,Ahn, Wha-Seung Elsevier Inc 2017 Journal of Energy Chemistry Vol.26 No.5

Synthesis of nanoporous materials via recycling coal fly ash and other solid wastes: A mini review

Lee, Yu-Ri,Soe, June Thet,Zhang, Siqian,Ahn, Ji-Whan,Park, Min Bum,Ahn, Wha-Seung Elsevier 2017 Chemical engineering journal Vol.317 No.-

<P><B>Abstract</B></P> <P>Large quantities of fly ash are discharged as a by-product from coal power plants. Therefore, an effective method to recycle this waste material is necessary. In this regard, the high silica content of fly ash makes it a potential useful source for the synthesis of nanoporous materials, such as zeolites, mesoporous silica or silica aerogels. In this mini review, zeolite synthesis from fly ash was examined by considering the ash composition, pretreatment procedures, and hydrothermal synthesis conditions (substrate composition and synthesis temperature/time) to identify an optimal set of synthesis conditions. These zeolites can be used as adsorbents and ion-exchangers for environmentally hazardous materials including those present in the fly ash itself. The synthesis of mesoporous silica materials with a high surface area and large pore volume derived from fly ash was next assessed for their use as a support and as a surface-functionalized host for capturing the global warming CO<SUB>2</SUB> and rare earth metal ions. Lastly, the utilization of fly ash for the preparation of silica aerogels or adiabatic foams, which are being considered as a potential building insulation materials, was briefly examined. Cases of synthesizing these nanoporous materials using other solid wastes as silica and/or alumina sources were also examined. The synthesis of diverse porous materials utilizing the waste sources would enable a high level of recycling for a sustainable society with a low environmental burden.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Physicochemical pre-treatment of fly ash for nanoporous materials synthesis. </LI> <LI> Synthesis of zeolites, mesoporous silica, and silica aerogel/foam from fly ash. </LI> <LI> Synthesis of nanoporous materials using solid wastes as silica and/or alumina sources. </LI> <LI> Applications of the synthesized nanoporous materials via fly ash recycling for sustainability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Experimental and analytical performance evaluation of steel beam to concrete-encased composite column with unsymmetrical steel section joints

Yunfeng Xiao,Lei Zeng,Zhenkun Cui,Siqian Jin,Yiguang Chen 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.23 No.1

The seismic performance of steel beam to concrete-encased composite column with unsymmetrical steel section joints is investigated and reported within this paper. Experimental and analytical evaluation were conducted on a total of 8 specimens with T-shaped and L-shaped steel section under lateral cyclic loading and axial compression. The test parameters included concrete strength, stirrup ratio and axial compression ratio. The response of the specimens was presented in terms of their hysterisis loop behavior, stress distribution, joint shear strength, and performance degradation. The experiment indicated good structural behavior and good seismic performance. In addition, a three-dimensional nonlinear finite-element analysis simulating was conducted to simulate their seismic behaviors. The finite-element analysis incorporated both bond-slip relationship and crack interface interaction between steel and concrete. The results were also compared with the test data, and the analytical prediction of joint shear strength was satisfactory for both joints with T-shaped and L-shaped steel section columns. The steel beam to concrete-encased composite column with unsymmetrical steel section joints can develop stable hysteretic response and large energy absorption capacity by providing enough stirrups and decreased spacing of transverse ties in column.