Fabrication and Application of Polyethylenimine/Ca-Alginate Blended Hydrogel Fibers as High-Capacity Adsorbents for Recovery of Gold from Acidic Solutions

Bediako, John Kwame,Song, Myung Hee,Yun, Yeoung Sang Trans Tech Publications, Ltd. 2017 Diffusion and defect data. SSP. [Pt. B], Solid sta Vol.262 No.-

<P>High-capacity polyethylenimine (PEI)/Ca-alginate blended hydrogel fibers were fabricated via three steps, viz. electrostatic blending of PEI and alginate, ionotropic gelation of alginate and CaCl2, and fixing of PEI into the Ca-alginate matrix, using glutaraldehyde (GA) as a crosslinker. Two crosslinking approaches resulted in different stabilities and gold uptake capacities of the prepared sorbents. Post-crosslinking approach was more efficient than pre-crosslinking likely owing to the better crosslinking efficiency, leading to better stability and sorption capacity. Furthermore, X-ray diffraction (XRD) study revealed the reduction of Au (III) to metallic gold, Au (0) in the crosslinked fibers. The Au (0) predominancy was confirmed with a metal desorption study. The present study thus demonstrates the possibility of recovering metallic gold from aqueous solutions by direct adsorption-coupled-reduction approach using GA-crosslinked PEI/Ca-alginate fibers.</P>

High-performance and acid-tolerant polyethylenimine-aminated polyvinyl chloride fibers: fabrication and application for recovery of platinum from acidic wastewaters

Bediako, John Kwame,Park, Sang Won,Choi, Jong-Won,Song, Mung-Hee,Yun, Yeoung-Sang Elsevier 2019 Journal of environmental chemical engineering Vol.7 No.1

<P><B>Abstract</B></P> <P>We report the fabrication and application of high-performance and acid-tolerant fibers comprising polyethylenimine (PEI) and polyvinyl chloride (PVC) for platinum recovery from acidic waste solutions. The fibers were fabricated by amination of PVC with PEI and spin-extrusion via phase-inversion mechanism. Factors including the effects of chloride concentration, pH, competing ions, and amount of PEI on the adsorption performance, were studied. The adsorption mechanism was evaluated through XPS analysis, in which electrostatic binding of Pt(IV) and its partially reduced Pt(II) were revealed. The maximum Pt adsorption capacity in 0.1 M HCl was estimated by the Langmuir isotherm model as 410.53 mg/g. The fibers were applicable to Pt recovery from actual metal refining wastewater and demonstrated high efficiency of regeneration through adsorption-desorption cycles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High Pt(IV) recovery efficiency was achieved with adsorbent fibers consisting of polyethylenimine and polyvinyl chloride. </LI> <LI> The prepared fibers were self-crosslinked, thereby requiring no extra crosslinking for chemical stability and adsorption. </LI> <LI> Compared with Amberjet 4200 commercial resin and others, the Pt(IV) recovery efficiency of the prepared fibers was highest. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Conversion of waste textile cellulose fibers into heavy metal adsorbents

Bediako, J.K.,Wei, W.,Yun, Y.S. Korean Society of Industrial and Engineering Chemi 2016 Journal of industrial and engineering chemistry Vol.43 No.-

<P>Fibrous adsorbents were prepared by carboxymethylation of waste textile fibers and were used for Cd(II) sorption in comparison with Dowex Mac-3 (DM-3). The prepared sorbents were designated carboxymethyl cellulose-Lyocell strands (CMC-LS) and carboxymethyl cellulose-Lyocell fabrics (CMC-LF). Kinetic and isotherm studies indicated that CMC-LS had the fastest sorption rate with high affinity constants and good column application potential. For the same packed column volume, CMC-LS reached similar to 70% of its capacity whilst DM-3 reached similar to 57%. 100% desorption was achieved using 0.1 M EDTA or HCl. This study therefore suggests a way to recycle waste fibers into adsorbents for treating heavy metal-polluted waters. (C) 2016 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.</P>

Preparation, characterization and lead adsorption study of tripolyphosphate-modified waste Lyocell fibers

Bediako, John Kwame,Reddy, D. Harikishore Kumar,Song, Myung-Hee,Wei, Wei,Lin, Shuo,Yun, Yeoung-Sang Elsevier 2017 Journal of environmental chemical engineering Vol.5 No.1

<P><B>Abstract</B></P> <P>A facile modification of waste textile cellulose Lyocell fibers with tripolyphosphate and application of the adsorbent thereof to the treatment of Pb(II)-contaminated wastewater was investigated. Characterization and batch adsorption studies were conducted to understand the characteristics of the prepared adsorbent and its metal binding mechanisms. The adsorbent showed 100% adsorptive removal efficiency of Pb(II) at initial concentrations up to 300mg/L, and the adsorption performance was significant even at low pH ranges. The adsorption isotherm followed the Langmuir model, and the kinetic was described by the pseudo-first and pseudo-second order models. By comparison, the adsorbent showed strong competitiveness to existing ones especially in terms of the adsorption capacity, pH, and kinetics of adsorption, and could be reused. Considering its cheap source and simplicity of preparation, the adsorbent could be applied as a low-cost material for heavy metal scavenging from wastewater streams.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A facile method for preparing cellulosic heavy metal adsorbent with phosphate chelating groups was presented. </LI> <LI> High selectivity of Pb(II) was found in multi-metal systems. </LI> <LI> Hundred percent adsorption efficiency of Pb(II) at initial concentrations up to 300mg/L was achieved. </LI> <LI> Adsorption capacity was very high even at low pH. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Heterointerface effects in the electrointercalation of van der Waals heterostructures

Bediako, D. Kwabena,Rezaee, Mehdi,Yoo, Hyobin,Larson, Daniel T.,Zhao, S. Y. Frank,Taniguchi, Takashi,Watanabe, Kenji,Brower-Thomas, Tina L.,Kaxiras, Efthimios,Kim, Philip Nature Publishing Group UK 2018 Nature Vol.558 No.7710

Molecular-scale manipulation of electronic and ionic charge accumulation in materials is the backbone of electrochemical energy storage<SUP>1–4</SUP>. Layered van der Waals (vdW) crystals are a diverse family of materials into which mobile ions can electrochemically intercalate into the interlamellar gaps of the host atomic lattice<SUP>5,6</SUP>. The structural diversity of such materials enables the interfacial properties of composites to be optimized to improve ion intercalation for energy storage and electronic devices<SUP>7–12</SUP>. However, the ability of heterolayers to modify intercalation reactions, and their role at the atomic level, are yet to be elucidated. Here we demonstrate the electrointercalation of lithium at the level of individual atomic interfaces of dissimilar vdW layers. Electrochemical devices based on vdW heterostructures<SUP> 13</SUP> of stacked hexagonal boron nitride, graphene and molybdenum dichalcogenide (MoX<SUB>2</SUB>; X = S, Se) layers are constructed. We use transmission electron microscopy, in situ magnetoresistance and optical spectroscopy techniques, as well as low-temperature quantum magneto-oscillation measurements and ab initio calculations, to resolve the intermediate stages of lithium intercalation at heterointerfaces. The formation of vdW heterointerfaces between graphene and MoX<SUB>2</SUB> results in a more than tenfold greater accumulation of charge in MoX<SUB>2</SUB> when compared to MoX<SUB>2</SUB>/MoX<SUB>2</SUB> homointerfaces, while enforcing a more negative intercalation potential than that of bulk MoX<SUB>2</SUB> by at least 0.5 V. Beyond energy storage, our combined experimental and computational methodology for manipulating and characterizing the electrochemical behaviour of layered systems opens new pathways to control the charge density in two-dimensional electronic and optoelectronic devices.

Conversion of waste textile cellulose fibers into heavy metal adsorbents

John Kwame Bediako,Wei Wei,윤영상 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.43 No.-

Fibrous adsorbents were prepared by carboxymethylation of waste textilefibers and were used for Cd(II)sorption in comparison with Dowex Mac-3 (DM-3). The prepared sorbents were designatedcarboxymethyl cellulose-Lyocell strands (CMC-LS) and carboxymethyl cellulose-Lyocell fabrics (CMCLF). Kinetic and isotherm studies indicated that CMC-LS had the fastest sorption rate with high affinityconstants and good column application potential. For the same packed column volume, CMC-LS reached70% of its capacity whilst DM-3 reached57%. 100% desorption was achieved using 0.1 M EDTAor HCl. This study therefore suggests a way to recycle wastefibers into adsorbents for treating heavymetal-polluted waters.

The Sheaf Offering and Resurrection Sunday

( Daniel K. Bediako ) 삼육대학교 선교와사회문제연구소 2017 Asia-Africa Journal of Mission and Ministry(AAMM) Vol.16 No.-

The Old Testament instructs that on the “morrow of the Sabbath” during the Feast of Passover and Unleavened Bread, the priest must raise the sheaf of barely, being the first of the firstfruits (Lev. 23:11-16). The “morrow of the Sabbath” has received polarized interpretations since Second Temple Judaism, including a sharp divide between the Pharisees and the Sadducees among others. Through an exegetical analysis of Leviticus 23:11-16, this study suggests (1) that “Sabbath” here refers to the weekly Sabbath that occurred during the feast and that in comparison with relevant New Testament texts, the sheaf elevation rite foreshadowed the raising of Christ on the “morrow of the Sabbath”; and (2) that inasmuch as the raising of the sheaf prefigured Christ’s resurrection, the annual Israelite presentation of this offering constituted an Old Testament ‘Resurrection Sunday’. Even though the Old Testament predicts through this ritual that Christ would resurrect on a Sunday, it never points to a change thereon from seventh-day Sabbath worship to Sunday worship.

Deuteronomy 20:19-20 and Its Implications for Ecology in African Societies

Daniel K. Bediako 삼육대학교 신학연구소 2019 신학과 학문 Vol.26 No.-

The descriptions of warfare in the Old Testament and the rules of engagement in Deuteronomy 20 have raised both hermeneutical and ethical questions. Verses 19-20 proscribe the wanton destruction of trees, especially fruit trees. This study analyzes the passage exegetically and suggests how it can be applied especially in African societies. Although the context of the passage is warfare, the injunction it presents has ecological and humanitarian underpinnings that can be applied in other contexts.

Sabbath in the Book of Isaiah

( Daniel K Bediako ) 삼육대학교 선교와사회문제연구소 2012 Asia-Africa Journal of Mission and Ministry(AAMM) Vol.6 No.-

The Sabbath is an important theological concept in the book of Isaiah. The significance attached to the Sabbath does not only find expression in the prediction of its observance in the renewed conditions following the captivity, but also in the fact that continual possession of the promised land would depend upon proper Sabbath-keeping. The final verses connect Sabbath-keeping with eschatology by implying that Sabbath will be observed in the "new heavens and new earth." Through contextual analysis, however, it is suggested that the eschatology in this text is best understood in a postexilic sense (i.e., an extended period following the return from captivity) rather than in an apocalyptic sense. Further, the creation of "new heavens and new earth" is to be understood as a highly poetic expression anchoring the redemption and restoration of Judah from the Babylonian captivity. Sabbath-keeping sums up righteousness.

Development of Low-Cost and Highly Regeneratable Biosorbent from Waste Lyocell Using Response Surface Methodology and Application to the Biosroption of Cd(II) Ions

( John Kwame Bediako ),윤영상,( Wei Wei ) 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.0