A Facile and TGA Free Hydrothermal Synthesis of SnS Nanoparticles

Y. P. Venkata Subbaiah,Narayana Thota,M. Raghavender,Y. P. Venkata Subbaiah,G. Hema Chandra,K.T. Ramakrishna Reddy 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.10

"In this paper, we employed a simple and cost-effective thioglycolic acid (TGA) free hydrothermal method, based on thiourea hydrolysis of stannous chloride dihydrate [SnCl2 · 2H2O] at 160 ℃ – 190 ℃ for 6 h, for the synthesis of SnS nanoparticles. The effect of hydrothermal autoclave reaction temperature on various properties of SnS nanoparticles have been examined at length using X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy attached with EDAX (FE-SEM), transmission electron microscopy (TEM) and ultraviolet-visible (UV-Vis) spectroscopy. The results suggest that the crystallization of orthorhombic SnS nanoparticles, with size varying from 3 nm to 5 nm, formed at RT = 160 ℃. Further, the formation of SnS phase was confirmed by an IR Sn-S characteristic bands around 2350 cm -1, 1041 cm -1 and 570 cm -1, and four distinguished Raman peaks at 95 cm -1, 160 cm -1, 189 cm -1 and 220 cm -1. The mechanism for the formation of SnS nanoparticles have been proposed and discussed. The SnS nanoparticles have exhibited reaction temperature dependent morphological features like nanoflowers, nanoflakes, spherical nanoparticles and nanogranules. The absorbance studies indicated both strong direct and weak indirect allowed transitions for SnS nanoparticles and the associated band gaps were found to be 1.5 eV and 1.19 eV, respectively. The dual band gap combination of SnS would favor strong direct absorption of carriers and improved minority carrier life time due to indirect nature, which means the grown particles are suitable for ideal absorber material for solar cell applications. "

Adsorption of methyl orange from aqueous solution by aminated pumpkin seed powder: Kinetics, isotherms, and thermodynamic studies

Subbaiah, M.V.,Kim, D.S. Academic Press 2016 Ecotoxicology and environmental safety Vol.128 No.-

<P>Present research discussed the utilization of aminated pumpkin seed powder (APSP) as an adsorbent for methyl orange (MO) removal from aqueous solution. Batch sorption experiments were carried to evaluate the influence of pH, initial dye concentration, contact time, and temperature. The APSP was characterized by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The experimental equilibrium adsorption data were fitted using two two-parameter models (Langmuir and Freundlich) and two three-parameter models (Sips and Toth). Langmuir and Sips isotherms provided the best model for MO adsorption data. The maximum monolayer sorption capacity was found to be 200.3 mg/g based on the Langmuir isotherm model. The pseudo-first-order and pseudo second -order model equations were used to analyze the kinetic data of the adsorption process and the data was fitted well with the pseudo-second-order kinetic model (R-2 > 0.97). The calculated thermodynamic parameters such as AG, AH and AS from experimental data showed that the sorption of MO onto APSP was feasible, spontaneous and endothermic in the temperature range 298-318 K. The FUR results revealed that amine and carboxyl functional groups present on the surface of APSP. The SEM results show that APSP has an irregular and porous surface which is adequate morphology for dye adsorption. Desorption experiments were carried to explore the feasibility of adsorbent regeneration and the adsorbed MO from APSP was desorbed using 0.1 M NaOH with an efficiency of 93.5%. Findings of the present study indicated that APSP can be successfully used for removal of MO from aqueous solution. (C) 2016 Elsevier Inc. All rights reserved.</P>

Synthesis and characterization of graphene oxide-doped nano-hydroxyapatite and its adsorption performance of toxic diazo dyes from aqueous solution

Prabhu, Subbaiah Muthu,Khan, Abuzar,Hasmath Farzana, M.,Hwang, Gil Chan,Lee, Woojin,Lee, Giehyeon Elsevier 2018 Journal of molecular liquids Vol.269 No.-

<P>In this study, graphene oxide-doped nano-hydroxyapatite (nHAp@GO) composite was synthesized via a simple in-situ one-pot method and was used as an adsorbent for the removal of toxic diazo dyes, Congo Red (CR) and Trypan Blue (TB), in water. A remarkable adsorption capacity for CR (48.5 mg/g) and TB (41.0 mg/g) were shown on the surface of nHAp@GO (2 g/L), respectively, and was much higher than those of bare nHAp or GO. After doping of GO on nHAp, the specific surface area of nHAp was increased by 2.5 times. The presence of sulphur peak in EDX spectrum and S-O stretching vibration peak in FTIR confirmed the adsorption of dyes on the surface of nHAp@GO composite. After the adsorption process, the shifting of d((100)) spacing of nHAp confirmed the loading of bulky organic moieties on nHAp@GO composite. Maximum CR and TB dyes adsorption occurred in a wide range of initial pH between 3.0 and 10.0. The adsorption of both CR and TB dyes are due mainly to the electrostatic interaction, pi - pi stacking interaction, hydrophobic interaction, and hydrogen bonds between dyes and nHAp@GO composite. The nHAp@GO nanocomposite was recycled up to three times at the sustained efficiency after washing with ethanol solution. We believe that such multifunctional material developed in this study will be effectively used for the depollution of toxic diazo dyes in practical applications. (C) 2018 Elsevier B.V. All rights reserved.</P>

A mechanistic investigation of highly stable nano ZrO₂ decorated nitrogen-rich azacytosine tethered graphene oxide-based dendrimer for the removal of arsenite from water

Prabhu, Subbaiah Muthu,Pawar, Radheshyam Rama,Sasaki, Keiko,Park, Chang Min Elsevier 2019 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.370 No.-

<P><B>Abstract</B></P> <P>We focused to synthesize graphene oxide-polyamidoamine dendrimer, up to 2nd generation, (GO-gen2) <I>via</I> a grafting method and the tethered groups were further covalently functionalized with a nitrogen-rich of an aromatic triazine ring of 5-azacytosine (Aza). Zirconia nanoparticles (ZrO<SUB>2</SUB>) has been identified as promising material for removal of AsO<SUB>3</SUB> <SUP>3−</SUP> from water, however, its practical applicability is hindered due to its nanosize. Hence, ZrO<SUB>2</SUB> was successfully decorated through biomolecule assist on GO-gen2-Aza dendrimer. Various amounts of GO-gen2-Aza were used as stable supports to develop the nanocomposites with ZrO<SUB>2</SUB>. Then, the adsorption efficiency of highly toxic AsO<SUB>3</SUB> <SUP>3−</SUP> on developed composites was investigated for water treatment. The synthesized GO-dendrimer composites were characterized well before and after adsorption of AsO<SUB>3</SUB> <SUP>3−</SUP> using FTIR, PXRD, SEM, XPS, TGA, TEM and BET analysis. Particle size distribution of ZrO<SUB>2</SUB> revealed the peak top at 28 nm by zeta potential measurement. During synthesis, the GO sheets of composite were laminated by incorporation of ZrO<SUB>2</SUB> nanoparticles. The results of the batch experiments showed that ZrO<SUB>2</SUB>@2%GO-gen2-Aza dendrimer had higher adsorption density of AsO<SUB>3</SUB> <SUP>3−</SUP> than that of other developed forms of dendrimer composites. Langmuir equation well described the adsorption isotherm with the maximum adsorption capacity of 1.075 mmol/g. In addition, the enhanced AsO<SUB>3</SUB> <SUP>3−</SUP> adsorption density on ZrO<SUB>2</SUB> surface of ZrO<SUB>2</SUB>@x%GO-gen2-Aza, in which the GO-sheets were delaminated, resulting more ZrO<SUB>2</SUB> was dispersed homogeneously in the GO-sheets for maximum uptake of AsO<SUB>3</SUB> <SUP>3−</SUP> from water, confirmed by PXRD patterns. These results suggested that the developed GO-based dendrimer materials can be utilised for the practical remediation of toxic AsO<SUB>3</SUB> <SUP>3−</SUP> and other similar types of toxic ions, selenite, phosphate and fluoride from the contaminated water.</P> <P><B>Highlights</B></P> <P> <UL> <LI> ZrO<SUB>2</SUB> entrapped GO-based Aza-tethered PAMAM dendrimer composite is prepared. </LI> <LI> Ligand exchange is likely responsible for the adsorption of AsO<SUB>3</SUB> <SUP>3−</SUP>. </LI> <LI> The lamination/delamination chemistry of GO-dendrimer composite are expressed. </LI> <LI> Maximum adsorption capacity of 1.075 mmol/g was achieved for AsO<SUB>3</SUB> <SUP>3−</SUP>. </LI> <LI> Selectivity and reusability test (4 cycles) did not affect the efficiency of AsO<SUB>3</SUB> <SUP>3−</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Biosorption of nickel (II) from aqueous solution by Trametes versicolor (rainbow) biomass: Equilibrium, kinetics and thermodynamic studies

Venkata Subbaiah MUNAGAPATI,Yeong-Sang YUN 한국생물공학회 2011 한국생물공학회 학술대회 Vol.2011 No.4

Entry to Highly Hindered Chiral β-Amino Triazoles Bearing a gem-Diaryl Group by Azide-alkyne Click Chemistry

Venkata Subbaiah Sadu,Harendra Nath Roy,Pitchaiah Arigala,In Taek Hwang,Kee-InLee 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.6

Copper(I)-catalyzed Huisgen cycloaddition of terminal alkynes with unmasked azidoamines derived from amino acids is described. The reported strategy provides a new entry to highly hindered β-amino 1,2,3-triazole derivatives bearing a gem-diaryl group, which are potentially valuable entities as molecular catalysts for asymmetric transformations.

입상 활성탄을 이용한 RB5수용액 흡착 반응의 동역학, 열역학, 그리고 등온선 연구

( Venkata Subbaiah Munagapati ),강지원 ( Ji-won Kang ),박은규 ( Eun-gyu Park ),김동수 ( Dong-su Kim ) 한국수처리학회 2016 한국수처리학회지 Vol.24 No.5

Present research discussed the utilization of granular activated carbon (GAC) as an adsorbent for Reactive black 5 (RB5) removal from aqueous solution. Batch adsorption experiments were carried to evaluate the influence of pH, adsorbent dosage, contact time, initial dye concentration and temperature. The equilibrium data were analyzed using the Langmuir and Freundlich isotherm models. Experimental data were best represented by the Langmuir isotherm model. The maximum monolayer adsorption capacity of RB5 onto GAC was found to be 32.02 ㎎/g. The pseudo-second-order kinetic model adequately described the kinetic data. Thermodynamic parameters (Δ Go, ΔHo and ΔSo) suggest that the adsorption process was spontaneous and endothermic in nature. Results in this study suggested that GAC was a suitable material for the removal of RB5 in aqueous solution.

Entry to Highly Hindered Chiral β-Amino Triazoles Bearing a gem-Diaryl Group by Azide-alkyne Click Chemistry

Sadu, Venkata Subbaiah,Roy, Harendra Nath,Arigala, Pitchaiah,Hwang, In-Taek,Lee, Kee-In Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.6

Copper(I)-catalyzed Huisgen cycloaddition of terminal alkynes with unmasked azidoamines derived from amino acids is described. The reported strategy provides a new entry to highly hindered ${\beta}$-amino 1,2,3-triazole derivatives bearing a gem-diaryl group, which are potentially valuable entities as molecular catalysts for asymmetric transformations.

Biosorption of Nickel(II) from Aqueous Solution by the Fungal Mat of Trametes versicolor (Rainbow) Biomass: Equilibrium, Kinetics, and Thermodynamic Studies

Munagapati Venkata Subbaiah,YEOUNG-SANG YUN 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.2

This study investigates the equilibrium, kinetics and thermodynamics of Nickel(II) biosorption from aqueous solution by the fungal mat of Trametes versicolor (rainbow) biomass. The optimum biosorption conditions like pH, contact time, biomass dosage, initial metal ion concentration and temperaturewere determined in the batch method. The biosorbent was characterized by FTIR, SEM and BET surface area analysis. The experimental data were analyzed in terms of pseudo-first-order, pseudo-secondorder and intraparticle diffusion kinetic models, further it was observed that the biosorption process of Ni(II)ions closely followed pseudo-second-order kinetics. The equilibrium data of Ni(II) ions at 303, 313, and 323 K were fitted to the Langmuir and Freundlich isotherm models. Langmuir isotherm provided a better fit to the equilibrium data andthe maximum monolayer biosorption capacity of the T. versicolor(rainbow) biomass for Ni(II) was 212.5 mg/g at pH 4.0. The calculated thermodynamic parameters, ΔGo,ΔHo, and ΔSo, demonstrated that the biosorption of Ni(II)ions onto the T. versicolor (rainbow) biomass was feasible,spontaneous and endothermic at 303 ~ 323 K. The performance of the proposed fungal biosorbent was also compared with that of many other reported sorbents for Nickel(II)removal and it was observed that the proposed biosorbent is effective in terms of its high sorption capacity.

Designed synthesis of sulfide-rich bimetallic-assembled graphene oxide sheets as flexible materials and self-tuning adsorption cum oxidation mechanisms of arsenic from water

Muthu Prabhu, Subbaiah,Park, Chang Min,Shahzad, Asif,Lee, Dae Sung The Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.19

<P>A superior flexible nanohybrid adsorbent with a <I>double-edged sword</I> structure, consisting of sulfide-rich bimetallic nanopowder of calcium lanthanum sulfide (CaLa2S4, CLS) assembled onto graphene oxide (GO), was successfully synthesized by a wet chemistry method and was used to adsorb both arsenite and arsenate ions from water. GO was used as a structure directing agent as well as a supporting material for CLS. Various amounts (5, 10, 20, and 50% wt/wt) of CLS were introduced on GO surfaces by intercalation to develop a nanohybrid and to investigate the efficiency of toxic arsenite and arsenate removal and surface interaction mechanisms. The CLS material was found to preferentially adsorb arsenate by reactions with calcium and lanthanum, while arsenite was adsorbed by sulfur using Pearson's hard and soft acids and bases (HSAB) principle. Various characterization techniques, such as FTIR, PXRD, Raman spectroscopy, TEM, SEM, XPS, CHS, BET, and zeta potential analyses were utilized before and after the adsorption of arsenite and arsenate. Batch experiment results showed that the CLS50%@GO composite had higher adsorption densities for both arsenite and arsenate than the other developed nanohybrids. Moreover, the Langmuir adsorption isotherm proved to better fit the data than the Freundlich isotherm, yielding maximum adsorption densities of 1.255 mmol g<SUP>−1</SUP> and 1.506 mmol g<SUP>−1</SUP> for arsenite and arsenate, respectively. The interactions between CLS and GO include complexation reactions with carboxyl and hydroxyl groups and a ring opening reaction at epoxy reactive sites along with the intercalation. The PXRD patterns clearly showed that the GO sheets were exfoliated during the loading of CLS with the aid of ultra-sonication which in turn enhanced the adsorption density and kinetic rate. After the adsorption of high concentrations of arsenite/arsenate on CLS50%@GO, the stability of the material was retained, as confirmed by PXRD results. The oxidation of arsenite to arsenate was confirmed by the presence of a new peak at <I>E</I>B[As 3d] = 44.6 eV, supported by C 1s and O 1s spectra in XPS analysis. The results obtained from this study suggest that materials with this type of double-edged sword structure will be useful in practical water purification.</P>