Publications by authors named "Animes Kumar Golder"

9 Publications

  • Page 1 of 1

Step-Scheme Heterojunction between CdS Nanowires and Facet-Selective Assembly of MnO-BiVO for an Efficient Visible-Light-Driven Overall Water Splitting.

ACS Appl Mater Interfaces 2021 Sep 14;13(38):45475-45487. Epub 2021 Sep 14.

Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India.

The spatial separation and transport of photogenerated charge carriers is crucial in building an efficient photocatalyst for solar energy conversion into chemical energy. A step-scheme CdS/MnO-BiVO photocatalyst was synthesized by spatial deposition of MnO and one-dimensional (1D) CdS nanowires on a three-dimensional (3D) decahedron BiVO surface. The photocatalytic activity of CdS/MnO-BiVO for the overall water-splitting reaction was investigated without sacrificial reagent under visible light irradiation. The synthesized photocatalysts were thoroughly analyzed using high-end characterization techniques. The 5CdS/MnO-BiVO exhibited the highest H and O production rates of 1.01 and 0.51 mmol g h, respectively, with an apparent quantum yield of 11.3% in the absence of any sacrificial reagent. The excellent photoactivity is due to the presence of oxygen vacancies along with effective charge separation/transfer properties and strong interaction of cocatalysts (MnO and Pt) with the photocatalysts (BiVO and CdS) in the 5CdS/MnO-BiVO heterojunction. The significance of the presence of MnO and Pt cocatalysts on the selective facets of BiVO for efficient overall water splitting reaction is highlighted in this work.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.1c11740DOI Listing
September 2021

Kinetics, degradation mechanisms and antibiotic activity reduction of chloramphenicol in aqueous solution by UV/HO process.

Water Sci Technol 2021 Aug;84(3):524-537

Department of Chemical Engineering, Indian Institute of Science Education and Research Bhopal, Bhopal 462066, India.

In this study, the aim was to explore the effectiveness of the UV/HO photolysis (UVP) process in terms of antimicrobial activity reduction and increasing the mean oxidation number of carbon (MONC) under the degradation of chloramphenicol (CHPL) drug. CHPL degradation kinetics and the effects of foreign anions on CHPL degradation were explored in this study. The order of the inhibition effect was found as Cl > NO > HCO due to their different in HO radical scavenging capacity. A pseudo-first-order model for CHPL degradation was well established, and the rate constant (k) was 2.93 × 10 min (R = 0.98) in UVP. Thirteen intermediate products were detected in MS-chromatogram and were identified through different proposed degradation pathways. The cleavage of the amide side chain in CHPL was more effective in CHPL degradation due to an electrophilic attacks by HO radicals on it. The inactivation rates of E. coli were decreased due to the reduction of -NO group into -NH functional group in CHPL that leads to the production of low toxic compounds on CHPL degradation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2166/wst.2021.254DOI Listing
August 2021

Bio-inspired PtNPs/Graphene nanocomposite based electrocatalytic sensing of metabolites of dipyrone.

Anal Chim Acta 2021 Jul 3;1167:338562. Epub 2021 May 3.

Centre for the Environment, Indian Institute of Technology Guwahati, Assam, 781039, India; Department of Chemical Engineering, Indian Institute of Technology Guwahati, Assam, 781039, India. Electronic address:

Noble metal nanoparticles are known to electrocatalyze various redox reactions by improving the electron transfer kinetics. In the present study, we have introduced a facile bioinspired synthesis of PtNPs and their integration for the formation of PtNPs/graphene nanocomposite using Psidium guajava (guava) leaves extract. Graphene used in nanocomposite formulation was synthesized by exfoliation of graphite in water/acetone (25:75 v/v) mixture followed by mechanical shearing using ultrasonication and microwave irradiation. PtNPs/graphene nanocomposite was drop-cast onto a glassy carbon electrode (GCE, 3 mm dia). The electrocatalytic activity of PtNPs/graphene nanocomposite was tested in a three-electrode system for sensing of metabolic products of dipyrone (DIP) formed through 1 e and 2 e transfer reactions. The modified electrode exhibited almost 50% reduction in electrode resistance. The limit of detection was found to be 0.142 μM with sensitivities of 0.820 and 0.445 μA․μMcm for DIP concentration below and above 100 μM, respectively, using square wave voltammetry. The signal of sensing of metabolites of DIP was almost invariant in the presence of glucose, dopamine, uric acid, and ciprofloxacin; however, the response current was decayed by 20% within the 10th cycle. The sensing of DIP spiked in treated sewage-water and running tap-water samples was ∼100% recoverable and comparable with HPLC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.aca.2021.338562DOI Listing
July 2021

Synthesis of low-cost bentonite/Duranta erecta's fruit powder imbedded alginate beads and its application in surfactant removal.

Environ Sci Pollut Res Int 2021 Nov 13;28(42):58945-58957. Epub 2021 May 13.

Department of Chemical Engineering, Indian Institute of Technology Guwahati, Assam, 781039, India.

High industrialization and improved medical facilities are deteriorating aquatic bodies through untreated effluents. This study is aimed to design and characterize the bentonite, Duranta erecta, and their hybrid-alginate beads for the removal of cetyltrimethylammonium bromide (CTAB) from its aqueous solution. D. erecta's seed powder was treated by using a sonochemical method and embedded into alginate beads. All designed beads were characterized by using physicochemical methods, Fourier-transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) technique. Hybrid beads were found to form an appropriate hydrogel structure with maximum surface area per unit gram (544 cm g), 0.42 mg dry weight, and 2.70 mm diameter. Kinetics and intraparticle diffusion models were fitted where involvement of both chemisorption and intraparticle diffusion was observed during the initial 30 and post-30-min phase, respectively. Thermodynamic studies corroborated the spontaneity of the CTAB adsorption process. Bentonite alginate beads showed the highest adsorption capacity of 97.06 mg g in 100 mg L CTAB solution at optimized conditions, while hybrid-alginate beads showed excellent efficiency with a wide range of physicochemical conditions frame. Conclusively, designed beads can be used to remove the surfactant, i.e., CTAB, from industrial waste effluents for the betterment of water reservoirs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11356-021-14306-6DOI Listing
November 2021

Ciprofloxacin degradation in photo-Fenton and photo-catalytic processes: Degradation mechanisms and iron chelation.

J Environ Sci (China) 2019 Jun 27;80:82-92. Epub 2018 Sep 27.

Department of Chemical Engineering, Indian Institute of Technology Guwahati, Assam, 781039, India. Electronic address:

Ciprofloxacin (CIP) is a broad spectrum synthetic antibiotic drug of fluoroquinolones class. CIP can act as a bidentate ligand forming iron complexes during its degradation in the photo-Fenton process (PFP). This work investigates on PFP for the degradation of CIP to understand the formation mechanism and stability of iron complexes under ultraviolet (UV)-light illumination. A comparison was made with the UV-photocatalysis (UV/TiO) process where CIP doesn't form a complex. In PFP, the optimal dose of Fe and HO were found to be 1.25 and 10 mmol/L with pH of 3.5. An optimal TiO dose of 1.25 g/L was determined in the UV/TiO process. Maximum CIP removal and mineralization efficiency of 93.1% and 47.3% were obtained in PFP against 69.7% and 27.6% in the UV/TiO process. The mass spectra could identify seventeen intermediate products including iron-CIP complexes in PFP, and only seven intermediate products were found in the UV/TiO process with a majority of common products in both the processes. The proposed mechanism supported by the mass spectra bridged the routes of CIP cleavage in the PFP and UV/TiO process, and the decomposition pathway of Fe-CIP chelate complexes in PFP was also elucidated. Both in PFP and UV/TiO processes, the target site of HO radical attack was the secondary-N atom present in the piperazine ring of the CIP molecule. The death of Escherichia coli bacteria was 55.7% and 66.8% in comparison to the control media after 45 min of treatment in PFP and UV/TiO process, respectively.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jes.2018.09.016DOI Listing
June 2019

Ag-doping on ZnO support mediated by bio-analytes rich in ascorbic acid for photocatalytic degradation of dipyrone drug.

Chemosphere 2018 Oct 28;208:149-158. Epub 2018 May 28.

Department of Chemical Engineering, Indian Institute of Technology Guwahati, Assam 781039, India. Electronic address:

The analytes such as ascorbic acid (AA) present in Sechium edule were extracted (294 mg AA kg fruit) in an aqueous media for its potential application for Ag-doping onto wurtzite ZnO. The bandgap of ZnO was decreased to 2.85 eV at the optimal Ag-loading of 1.18% (w/w) against 3.13 eV for the control catalyst without using the analytes and, the commercial AA only could reduce the bandgap to 2.91 eV. The saturation photo-electrochemical current density (46.68 mA cm) at E ≥ 0.31 V vs. Ag/AgCl was almost double than pristine ZnO under visible light illumination (λ = 525 nm, 18 K lux) and, the current density was insignificant in the dark. The doped catalyst exhibited the maximum 79.5% degradation (71% COD removal) of an anti-analgesic drug, dipyrone (100 μg L dipyrone, catalyst 100 mg L) resulted from the formation of O radical (g-factor of 2.002-2.008) and paramagnetic oxygen vacancies (g-factor of 2.020) and, no effect of dye-sensitization was noted. The highest quantum yield was found to be 34.7%. The catalyst loss was 6% after the fourth cycle and the dipyrone degradation was reduced to 70.8%.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2018.05.158DOI Listing
October 2018

Synthesis and characterization of carboxylic cation exchange bio-resin for heavy metal remediation.

J Hazard Mater 2018 Jan 29;341:207-217. Epub 2017 Jul 29.

Department of Civil Engineering, Indian Institute of Technology Guwahati, India. Electronic address:

A new carboxylic bio-resin was synthesized from raw arecanut husk through mercerization and ethylenediaminetetraacetic dianhydride (EDTAD) carboxylation. The synthesized bio-resin was characterized using thermogravimetric analysis, field emission scanning electron microscopy, proximate & ultimate analyses, mass percent gain/loss, potentiometric titrations, and Fourier transform infrared spectroscopy. Mercerization extracted lignin from the vesicles on the husk and EDTAD was ridged in to, through an acylation reaction in dimethylformamide media. The reaction induced carboxylic groups as high as 0.735mM/g and a cation exchange capacity of 2.01meq/g functionalized mercerized husk (FMH). Potentiometric titration data were fitted to a newly developed single-site proton adsorption model (PAM) that gave pKa of 3.29 and carboxylic groups concentration of 0.741mM/g. FMH showed 99% efficiency in Pb(II) removal from synthetic wastewater (initial concentration 0.157mM), for which the Pb(II) binding constant was 1.73×10L/mol as estimated from modified PAM. The exhaustion capacity was estimated to be 18.7mg/g of FMH. Desorption efficiency of Pb(II) from exhausted FMH was found to be about 97% with 0.1N HCl. The FMH simultaneously removed lead and cadmium below detection limit from a real lead acid battery wastewater along with the removal of Fe, Mg, Ni, and Co.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jhazmat.2017.07.043DOI Listing
January 2018

Decomposition of drug mixture in Fenton and photo-Fenton processes: comparison to singly treatment, evolution of inorganic ions and toxicity assay.

Chemosphere 2015 May 6;127:254-61. Epub 2015 Mar 6.

Department of Chemical Engineering, Indian Institute of Technology Guwahati, Assam 781 039, India. Electronic address:

The degradation of three pharmaceutical compounds i.e. chloramphenicol (CHPL), ciprofloxacin (CIP) and dipyrone (DIPY) singly and from equimolar (CCD) mixture has been investigated in Fenton and photo-Fenton processes. Drug mineralization was slightly less when present singly than their mixture. The degradation efficiency was likely hindered due to formation of common ions like Cl(-), F(-), NH4(+) and NO3(-). Addition of the same ions i.e. Cl(-) and F(-) in drug solution released upon cleavage of CHPL and CIP in CCD mixture suppressed the decomposition efficiency remarkably in both the oxidation processes. The major intermediates appeared in the mass spectra in combination of ion chromatograph were used to validate the routes of CCD decomposition and evolution inorganic ions. Furthermore, the bacterial toxicity assay was investigated using Escherichia coli (E. coli). The average reduction in cell death was about 38% in CCD system compared to 52%, 42% and 47% for CHPL, CIP and DIPY, respectively.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2015.02.010DOI Listing
May 2015

Reduction of Cr(VI) into Cr(III) by Spirulina dead biomass in aqueous solution: kinetic studies.

Chemosphere 2013 Oct 18;93(7):1366-71. Epub 2013 Sep 18.

Department of Chemical Engineering, Indian Institute of Technology Guwahati, Assam 781 039, India.

Microalga species are potential scavengers of heavy metals. The active functional groups of a number of biomaterials are capable to detoxify Cr(VI) to Cr(III). A 2nd order kinetic model was developed in terms of concentration of protonated acidic groups of Spirulina sp. biomass for the reduction of Cr(VI) into Cr(III). Cr(VI) reduction reaction grounded on the concentration of functional groups was validated over a broad range of pH, temperature and anionic strength. Lower pH favoured Cr(VI) reduction reaction and the experimental results well fitted to the kinetic model. The overall rate constant, kt, decreased logarithmically from 22.7 to 2.8 mM⁻¹ s⁻¹ with rise of pH from 0.5 to 6.0. Whereas, k(t) increased nearly by 23% with elevation temperature from 25 to 45 °C. Higher concentration (>0.235 mM) of background anions (Cl⁻, SO₄²⁻ and NO₃⁻) was resulted in decreases in k(t) values. The rate constant expression developed can be employed to quantify Cr(VI) reduction into Cr(III) using Spirulina biomass.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2013.08.021DOI Listing
October 2013
-->