Techno-economic Analysis and Life Cycle Impact Assessment for the Valorisation of Kraft Lignin and Low-Voltage Hydrogen Production

Soltani Panah Hamidreza,Jeong Dong Hwi 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.3

This study presents a comparative techno-economic analysis and life cycle impact assessment of hydrogen production from the kraft lignin depolymerization (KLD) with those produced from alkaline electrolysis cell (AEC) and proton exchange membrane electrolysis (PEM). This process happens in a continuous modular fl ow reactor by using the phosphomolybdic acid as a redox-active catalyst and includes depolymerizing the kraft lignin, producing vanillin, acetovanillone, and hydrogen under a low-voltage condition. For the techno-economic analysis, fi rst, the processes were modelled by using the Aspen Plus V12.1 software and then the results were transferred to Aspen Process Economic Analyzer V12 for economic evaluation. In the next step, the life cycle impact assessment was proposed by using the openLCA V1.11.0 software along with the Environmental Footprint database (MID-Point indicator), and 18 impacts were investigated. According to the techno-economic analysis, KLD exhibits a total capital cost that surpasses that of AEC and PEM by more than 18% and 11%, respectively. Furthermore, KLD’s equipment cost exceeds that of AEC and PEM by approximately 0.5% and 7%, respectively, and necessitates additional components. On the other hand, the life cycle assessment revealed that KLD yields lesser environmental impacts than AEC, while PEM exhibits the most exemplary environmental performance.

Quick and enhanced degradation of bisphenol A by activation of potassium peroxymonosulfate to SO₄ ⁻ with Mn-doped BiFeO₃ nanoparticles as a heterogeneous Fenton-like catalyst

Soltani, Tayyebeh,Tayyebi, Ahmad,Lee, Byeong-Kyu Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.441 No.-

<P><B>Abstract</B></P> <P>Mn-doped BiFeO<SUB>3</SUB> magnetic nanoparticles (BFO MNPs), namely BiFe<SUB>1−x</SUB>Mn<SUB>x</SUB>O<SUB>3</SUB> (x = 0.05 and 0.10), were successfully synthesized using a simple and novel sol–gel method and then applied as a highly efficient peroxymonosulfate (KHSO<SUB>5,</SUB> PMS) activation catalyst for the fast degradation of bisphenol A (BPA) from aqueous solution. The strong PMS activation ability of 10% Mn-doped BFO MNPs without any metal leaching due to the simultaneous effects of iron and manganese ions in the production of radical sulfate (SO<SUB>4</SUB> <SUP> −</SUP>), caused complete BPA degradation in 15 min, which was much faster than that using combinations with H<SUB>2</SUB>O<SUB>2</SUB>. TOC was reduced to 33%, 23% and 13% by PMS activated with BFO, 5 and 10% Mn doped BFO, respectively, which are 2.1, 2.6 and 3.15-fold lower than that same nanoparticles activated with H<SUB>2</SUB>O<SUB>2</SUB>. The photocatalytic mechanism of BPA with the simultaneous effects of iron and manganese ions in Mn-doped BFO was explored. The addition of KBrO<SUB>3</SUB> and NaNO<SUB>3</SUB> salts into Mn-doped BFO/PMS system reduced the complete BPA degradation time to 10 min, whereas Na<SUB>2</SUB>CO<SUB>3</SUB> and NaCl salt addition retarded it, because salt addition can generate radical species that are either more or less active than SO<SUB>4</SUB> <SUP> −</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mn-doped BFO catalyst greatly improved the heterogeneous activation of PMS (HSO<SUB>5</SUB> <SUP>−</SUP>). </LI> <LI> HO<SUP> </SUP> or SO<SUB>4</SUB> <SUP> −</SUP> are the main species in the photo-Fenton catalytic oxidation of BPA. </LI> <LI> The coupling of HSO<SUB>5</SUB> <SUP>−</SUP> with Fe<SUP>2+</SUP> and Mn<SUP>2+</SUP> led to the effective formation of SO<SUB>4</SUB> <SUP> −.</SUP> </LI> <LI> Mn (10%)-doped BFO MNPs completely degraded BPA in 15 min with SO<SUB>4</SUB> <SUP> −.</SUP> </LI> <LI> KBrO<SUB>3</SUB> and NaNO<SUB>3</SUB> salts further increased BPA degradation as compared to PMS. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Efficient promotion of charge separation with reduced graphene oxide (rGO) in BiVO₄/rGO photoanode for greatly enhanced photoelectrochemical water splitting

Soltani, Teyyebah,Tayyebi, Ahmad,Lee, Byeong-Kyu Elsevier 2018 Solar Energy Materials and Solar Cells Vol. No.

<P><B>Abstract</B></P> <P>Although BiVO<SUB>4</SUB> (BVO) continues to attract strong attention as an ideal reactive semiconductor, its photoelectrochemical (PEC) water splitting performance remains low because most of the charge carriers are easily recombined in the bulk or on the surface of the photoanode before reaching the fluorine-doped tin dioxide (FTO). This study presents a facile and simple, visible-light-assisted, photocatalytic reduction of graphene oxide (GO) by using BVO for the preparation of highly stable BVO/reduced GO (rGO) nanocomposites with two different rGO weight ratios (5% and 10%). These as-prepared BVO/rGO nanocomposites were then drop-cast on an FTO substrate to demonstrate the key role played by the rGO in greatly improving the electron transport in the BVO/rGO films. In PEC water splitting experiments, the BVO/rGO-10% photoelectrode showed the highest photocurrent density (554.4 µA cm<SUP>−2</SUP> at 1.2 V vs. Ag/AgCl), compared to BVO (111.7 µA cm<SUP>−2</SUP>) and BVO/rGO-5% (377.9 µA cm<SUP>−2</SUP>). The stable BVO/rGO also showed the highest charge carrier density, with an extended lifetime and improved the electrical conductivity, as compared to BVO. These results contributed to the excellent PEC performance of the BVO/rGO photoanode. Under simulated solar light illumination, the open-circuit potential (OCP) of the BVO/rGO films was shifted to a more negative value due to the enhanced electron-hole separation in the films. The photocurrent yields of the BVO and BVO/rGO electrodes were dependent on the solution pH. The photocurrent densities were higher over the full range of measured potential (0 to + 1.2 V vs. Ag/AgCl) in the NaOH electrolyte (1 M, pH = 13.5) than in the Na<SUB>2</SUB>SO<SUB>4</SUB> electrolyte (0.1 M, pH = 6.5). This work demonstrates the essential role of the rGO coverage in the great enhancement of electron transport through the rGO in the BVO/rGO film.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Facile, visible-light-assisted, photocatalytic reduction of GO by BVO was developed. </LI> <LI> BVO/rGO greatly increased the photocurrent density up to 554.44 µA cm<SUP>−2</SUP>. </LI> <LI> BVO/rGO showed much better stability, photocurrent and IPCE than BVO did. </LI> <LI> BVO/rGO increased the charge carrier lifetime/concentration and electron conductivity. </LI> </UL> </P>

Low intensity-ultrasonic irradiation for highly efficient, eco-friendly and fast synthesis of graphene oxide

Soltani, Tayyebeh,Lee, Byeong-Kyu Butterworth Heinemann 2017 Ultrasonics sonochemistry Vol.38 No.-

<P><B>Abstract</B></P> <P>High quality graphene oxide (GO) with low layer number (less than five layers) and large inter-layer space was produced via a new and efficient method using environmentally friendly, fast and economic ultrasonic radiation. The ultrasonic method neither generated any toxic gas nor required any NaNO<SUB>3</SUB>, which have been the main drawbacks of the Hummers methods. The major obstacles of the recently reported improved Hummers method for GO synthesis, such as high reaction temperature (50°C) and long reaction time (12h), were successfully solved using a low intensity-ultrasonic bath for 45min at 30°C, which significantly reduced the reaction time and energy consumption for GO synthesis. Furthermore, ultrasonic GO exhibited higher surface area, higher crystallinity and higher oxidation efficiency with many hydrophilic groups, fewer sheets with higher spaces between them, a higher sp<SUP>3</SUP>/sp<SUP>2</SUP> ratio, and more uniform size distribution than classically prepared GO. Therefore, the new ultrasonic method could be applicable for the sustainable and large-scale production of GO. The production yield of the ultrasonic-assisted GO was 1.25-fold greater than the GO synthesized with the improved Hummers method. Furthermore, the required production cost based on total energy consumption for ultrasonic GO was only 6.5% of that for classical GO.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High quality GO was fabricated using an ultrasonic-assisted improved Hummers method (GO-Us). </LI> <LI> GO-Us was synthesized at short reaction time and low temperature (45min, 30°C). </LI> <LI> GO-Us synthesis did not require any NaNO<SUB>3</SUB> and did not generate any toxic gas evolution. </LI> <LI> GO-Us had minimized sheets, higher surface area, and greater oxygen functionality. </LI> </UL> </P>

dxz/yz orbital subband structures and chiral orbital angular momentum in the (001) surface states of SrTiO3

Soltani, Shoresh,Cho, Soohyun,Ryu, Hanyoung,Han, Garam,Kim, Beomyoung,Song, Dongjoon,Kim, Timur K.,Hoesch, Moritz,Kim, Changyoung American Physical Society 2017 Physical review. B Vol.95 No.12

<P>We performed angle-resolved photoemission spectroscopy (ARPES) experiments on the surface states of SrTiO3(001) using linearly and circularly polarized light to investigate the subband structures of out-of-plane d(xz/yz) orbitals and chiral orbital angular momentum (OAM). The data taken in the first Brillouin zone reveal new subbands for d(xz/yz) orbitals with Fermi wave vectors of 0.25 and 0.45 angstrom(-1) in addition to the previously reported ones. As a result, there are at least two subbands for all the Ti 3d t(2g) orbitals. Our circular dichroism ARPES data are suggestive of a chiral OAM structure in the surface states and may provide clues to the origin of the linear Rashba-like surface band splitting.</P>

A benign ultrasonic route to reduced graphene oxide from pristine graphite

Soltani, T.,Kyu Lee, B. Academic Press 2017 Journal of Colloid and Interface Science Vol. No.

In this study, we report the synthesis of high purity reduced graphene oxide (rGO) from pristine graphite via a fast and cost-effective one-step ultrasonic reduction method. Ultrasonic treatment was employed to avoid the harsh reaction conditions, including high temperature and use of highly toxic hydrazine, required for the conventional rGO preparation method. The high temperature produced during the ultrasound irradiation at low temperature and short reaction time enabled the reduction of graphene oxide (GO) into rGO without the use of toxic chemicals. The oxygen functional groups on GO were successfully reduced by the sonochemical reduction. The rGO prepared using the ultrasonic method exhibited a curled morphology, a very thin wrinkled paper-like structure, sheet folding, minimal layers (~4 layers), and a layer spacing of ~1nm. The sonochemical approach for the synthesis of rGO showed fast, high productivity, much improved safety, less energy, and time consuming characteristics as compared to other methods. More importantly, highly explosive and poisonous hydrazine is not required in this sonochemical technique, opposed to that required in conventional rGO synthesis, making it useful for many industrial applications of rGO.

Synthesis and structural characterization of three dinuclear Copper(II) complexes incorporating pyrazolyl-derived ligands

Soltani, Behzad,Sadr, Moayad Hossaini,Engle, James T.,Ziegler, Christopher J.,Joo, Sang Woo,Hanifehpour, Younes Springer-Verlag 2012 Transition metal chemistry Vol.37 No.8

Enhanced photoelectrochemical (PEC) and photocatalytic properties of visible-light reduced graphene-oxide/bismuth vanadate

Soltani, Teyyebah,Tayyebi, Ahmad,Lee, Byeong-Kyu Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.448 No.-

<P><B>Abstract</B></P> <P>A simple visible-light-assisted photocatalytic reduction of graphene oxide (GO) to reduced graphene oxide (rGO) using BiVO<SUB>4</SUB> (BVO) in BVO/GO was designed to remarkably improve the photocatalytic degradation and photoelectrochemical (PEC) water splitting efficiencies of BVO. The resulting smaller particle size and strong interfacial interaction on the graphene sheet of the prepared BVO/rGO nanocomposite (NC) enhanced the photocatalytic degradation of tetracycline (TC) and methylene blue (MB) from aqueous solution, and also PEC water splitting. The photocatalytic degradation of MB and TC from aqueous solution using BVO/rGO was enhanced almost 2-fold compared to using BVO with complete photodegradation being achieved in 60 and 55 min of visible-light irradiation, respectively. The photocurrent onset potential of BVO/rGO was negatively shifted by −0.2 V vs. Ag/AgCl. The photocurrent density of BVO/rGO was greatly improved to 133 µA cm<SUP>−2</SUP> at 0.8 V vs. Ag/AgCl, as compared to 21 µA cm<SUP>−2</SUP> with BVO. The charge recombination time was greatly increased from 5 s<SUP>−1</SUP> for BVO to 11 s<SUP>−1</SUP> for BVO/rGO. The BVO/rGO photoanode exhibited long-term operation stability by maintaining 90.2% of the initial photocurrent density after 2400 s, while BVO showed poor stability of 65.1%. The great improvement of photocatalytic (2.0-fold) and PEC water splitting activity (6.3-fold) in BVO/rGO was attributed to the longer electron lifetime (2.2-fold), enhanced carrier concentration (5.87-fold), reduced interfacial electron transfer resistance, excellent stability and reusability, reduced particle size, and extended photoresponse range, which were derived from the ultimate coverage of BVO by rGO.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Photocatalytic reduction of GO produced complete coverage of BVO by rGO sheets. </LI> <LI> Photodegradation of MB and TC was 2-fold greater than that using BVO. </LI> <LI> Photocurrent density of BVO/rGO (133 µA cm<SUP>−2</SUP>) was greatly increased compared to that of BVO (21 µA cm<SUP>−2</SUP>). </LI> <LI> BVO/rGO photoelectrode exhibited a very high stability of 90% even after 2400 s. </LI> <LI> Charge recombination time of BVO/rGO (11 s<SUP>−1</SUP>) was greatly increased compared to that of BVO (5 s<SUP>−1</SUP>). </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Enhanced formation of sulfate radicals by metal-doped BiFeO₃ under visible light for improving photo-Fenton catalytic degradation of 2-chlorophenol

Soltani, Tayyebeh,Lee, Byeong-Kyu Elsevier 2017 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.313 No.-

<P><B>Abstract</B></P> <P>Three metal doped BiFeO<SUB>3</SUB> magnetic nanoparticles (BFO MNPs), namely Bi<SUB>1−x</SUB>Ba<SUB>x</SUB>FeO<SUB>3</SUB> (x=0.03), BiFe<SUB>1−y</SUB>Cu<SUB>y</SUB>O<SUB>3</SUB> (y=0.1) and Bi<SUB>1−x</SUB>Ba<SUB>x</SUB>Fe<SUB>1−y</SUB>Cu<SUB>y</SUB>O<SUB>3</SUB> (x=0.03, y=0.1), were successfully prepared by a novel and simple sol-gel method. Then, iron and iron-copper heterogeneous Fenton-like photocatalysts were applied to activate H<SUB>2</SUB>O<SUB>2</SUB> to hydroxyl radicals ( <SUP> </SUP> OH ) and persulfate (S<SUB>2</SUB>O<SUB>8</SUB> <SUP>2−</SUP>) to sulfate radical anions ( SO 4 - ) for enhanced degradation of 2-chlorophenol (2-CP) from aqueous solution. Both Fe<SUP>3+</SUP>/Fe<SUP>2+</SUP> and Cu<SUP>+</SUP>/Cu<SUP>2+</SUP> pairs in the BFO MNPs systems effectively decomposed H<SUB>2</SUB>O<SUB>2</SUB> to <SUP> </SUP> OH and S<SUB>2</SUB>O<SUB>8</SUB> <SUP>2−</SUP> to SO 4 - . After only 70min of visible light irradiation, Cu-doped BFO (BiFe<SUB>1−y</SUB>Cu<SUB>y</SUB>O<SUB>3</SUB>) and Ba-Cu co-doped BFO (Bi<SUB>1−x</SUB>Ba<SUB>x</SUB>Fe<SUB>1−y</SUB>Cu<SUB>y</SUB>O<SUB>3</SUB>) almost completely degraded 2-CP with reductions in total organic carbon (TOC) of 68 and 73%, respectively, which were much higher than that achieved with BFO and Ba-doped BFO, due to the formation of <SUP> </SUP> OH in the Cu<SUP>2+</SUP>/Fe<SUP>2+</SUP>/H<SUB>2</SUB>O<SUB>2</SUB>/visible light couple. However, 2-CP was completely degraded with Cu-doped BFO and Ba-Cu co-doped BFO in less than 30min, due to the effective formation of SO 4 - in the Cu<SUP>2+</SUP>/Fe<SUP>2+</SUP>/S<SUB>2</SUB>O<SUB>8</SUB> <SUP>2−</SUP>/visible light couple. Cu<SUP>2+</SUP> or Fe<SUP>2+</SUP> ions in H<SUB>2</SUB>O<SUB>2</SUB>/visible light or S<SUB>2</SUB>O<SUB>8</SUB> <SUP>2−</SUP>/visible light couples are important species in the improved degradation of 2-CP in the photo-Fenton catalytic reaction. However, the photo-Fenton catalytic degradation of 2-CP was greatly reduced in the absence of any species of Cu<SUP>2+</SUP> or Fe<SUP>2+</SUP> ions, H<SUB>2</SUB>O<SUB>2</SUB>, S<SUB>2</SUB>O<SUB>8</SUB> <SUP>2−</SUP>, and visible light irradiation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <SUP> HO </SUP> or SO 4 - are important species in the photo-Fenton catalytic oxidation of 2-CP. </LI> <LI> The coupling of S<SUB>2</SUB>O<SUB>8</SUB> <SUP>2−</SUP> with Fe<SUP>2+</SUP> and Cu<SUP>2+</SUP> led to the effective formation of SO 4 - . </LI> <LI> Cu or Ba-Cu-doped BFO MNPs completely degraded 2-CP in less than 30min with SO 4 - . </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

APPLICATIONS ON THE BESSEL-STRUVE-TYPE FOCK SPACE

Soltani, Fethi Korean Mathematical Society 2017 대한수학회논문집 Vol.32 No.4

In this work, we establish Heisenberg-type uncertainty principle for the Bessel-Struve Fock space ${\mathbb{F}}_{\nu}$ associated to the Airy operator $L_{\nu}$. Next, we give an application of the theory of extremal function and reproducing kernel of Hilbert space, to establish the extremal function associated to a bounded linear operator $T:{\mathbb{F}}_{\nu}{\rightarrow}H$, where H be a Hilbert space. Furthermore, we come up with some results regarding the extremal functions, when T are difference operators.