Crystal structures of hybrid completely reduced phosphomolybdates and catalytic performance applied as molecular catalysts for the reduction of chromium(VI)

2018 ◽  
Vol 74 (11) ◽  
pp. 1310-1324 ◽  
Author(s):  
Xuerui Tian ◽  
Xing Xin ◽  
Yuanzhe Gao ◽  
Dandan Dai ◽  
Jinjin Huang ◽  
...  
Keyword(s):  
Environmental Remediation ◽  
Catalytic Reduction ◽  
Noncovalent Interactions ◽  
Low Cost ◽  
Catalytic Performance ◽  
Vital Role ◽  
Chromium Vi ◽  
Highly Active ◽  
Supramolecular Networks ◽  
Molecular Catalysts

The exploration of highly efficient and low-cost catalysts for the treatment of hexavalent chromium CrVI in environmental remediation is currently one of the most challenging topics. Here, three phosphomolybdate hybrid compounds have been successfully isolated by the hydrothermal method and been applied as supramolecular catalysts for the reduction of CrVI. Single-crystal X-ray diffraction revealed their formulae as (H2bpp)2[Fe(H2O)][Sr(H2O)4]2{Fe[Mo6O12(OH)3(H2PO4)(HPO4)(PO4)2]2}·5H2O (1), (H2bpp)2[Na(H2O)(OC2H5)][Fe(H2O)2][Ca(H2O)2]2{Fe[Mo6O12(OH)3(H2PO4)(HPO4)(PO4)2]2}·4H2O (2) and (H2bpe)3{Fe[Mo6O12(OH)3(HPO4)3(H2PO4)]2}·8H2O (3) [bpp is 1,3-bis(pyridin-4-yl)propane (C13H14N2) and bpe is trans-1,2-bis(pyridin-4-yl)ethylene (C12H10N2)]. The three hybrids consist of supramolecular networks built up by noncovalent interactions between {Fe[P4Mo6 VO31]2}22− polyanions and protonated organic cations. This kind of hybrid polyoxometalate could be applied as heterogeneous molecular catalysts for the reduction of CrVI. It was found that the organic moiety plays a vital role in influencing the catalytic activity of the polyanions. Organic bpp-containing hybrids 1 and 2 are highly active in the catalytic reduction of heavy metal CrVI ions using HCOOH as reductant, while bpe-containing hybrid 3 is inactive to this reaction. This work is significant for the design of new catalysts, as well as the exploration of reaction mechanisms at a molecular level.

scholarly journals Optimization of sol-immobilized bimetallic Au–Pd/TiO 2 catalysts: reduction of 4-nitrophenol to 4-aminophenol for wastewater remediation

2020 ◽  
Vol 378 (2176) ◽  
pp. 20200057
Author(s):  
Khaled Alshammari ◽  
Yubiao Niu ◽  
Richard E. Palmer ◽  
Nikolaos Dimitratos
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Reducing Agent ◽  
Wastewater Remediation ◽  
X Ray ◽  
Molar Ratios ◽  
Highly Active ◽  
Transmission Electron ◽  
Complementary Techniques

A sol-immobilization method is used to synthesize a series of highly active and stable Au x Pd 1− x /TiO 2 catalysts (where x  = 0, 0.13, 0.25, 0.5, 0.75, 0.87 and 1) for wastewater remediation. The catalytic performance of the materials was evaluated for the catalytic reduction of 4-nitrophenol, a model wastewater contaminant, using NaBH 4 as the reducing agent under mild reaction conditions. Reaction parameters such as substrate/metal and substrate/reducing agent molar ratios, reaction temperature and stirring rate were investigated. Structure-activity correlations were studied using a number of complementary techniques including X-ray powder diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy. The sol-immobilization route provides very small Au–Pd alloyed nanoparticles, with the highest catalytic performance shown by the Au 0.5 Pd 0.5 /TiO 2 catalyst. This article is part of a discussion meeting issue ‘Science to enable the circular economy’.

scholarly journals Highly efficient and simultaneous catalytic reduction of multiple toxic dyes and nitrophenols waste water using highly active bimetallic PdO–NiO nanocomposite

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. G. Ramu ◽  
Dongjin Choi
Keyword(s):  
Rate Constant ◽  
Catalytic Reduction ◽  
Low Cost ◽  
Reduction Rate ◽  
Aquatic Organism ◽  
Significant Loss ◽  
Azo Compounds ◽  
Highly Active ◽  
High Efficient ◽  
High Reduction

AbstractAzo dyes and nitrophenols have been widely used in the various industry which are highly toxic and affecting the photosynthetic cycle of aquatic organism. The industry disposals increase the accumulation of azo compounds in the environment. In the present study, we synthesized the low cost, PdO-doped NiO hetero-mixture via simple hydrothermal combined calcination process. The morphology results proved that, the spherical PdO nanoparticles are evenly doped with NiO nanoparticles. The band gap values of metal oxides NiO, PdO and PdO–NiO composite were found to be 4.05 eV, 3.84 eV and 4.24 eV, respectively. The high optical bandgap (Eg) value for composite suggests that the PdO interface and NiO interface are closely combined in the composite. The catalytic activity of the PdO–NiO was analyzed for the reduction of different toxic azo compounds namely, 4-nitrophenol (NP), 2,4-dinitrophenol (DNP), 2,4,6-trinitrophenol (TNP), methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) separately and their mixture with the presence of a NaBH4. For the first time, the large volume of the toxic azo compounds was reduced into non-toxic compounds with high reduction rate. The proposed PdO–NiO catalyst exhibit excellent rate constant 0.1667, 0.0997, 0.0686 min−1 for NP, DNP and TNT and 0.099, 0.0416 and 0.0896 min−1 for MB, RhB and MO dyes respectively which is higher rate constant than the previously reported catalysts. Mainly, PdO–NiO completes the reduction of mixture of azo compounds within 8 min. Further, PdO–NiO exhibit stable reduction rate of azo compounds over five cycles with no significant loss. Hence, the proposed low cost and high efficient PdO–NiO catalyst could be the promising catalyst for degradation of azo compounds.

scholarly journals Catalytic Reduction of Hexavalent Chromium Using Iron/Palladium Bimetallic Nanoparticle-Assembled Filter Paper

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1183 ◽  
Author(s):  
Daniel Shi ◽  
Zhijun Ouyang ◽  
Yili Zhao ◽  
Jie Xiong ◽  
Xiangyang Shi
Keyword(s):  
Hexavalent Chromium ◽  
Filter Paper ◽  
Environmental Remediation ◽  
Bimetallic Nanoparticles ◽  
Catalytic Reduction ◽  
Low Cost ◽  
Bimetallic Nanoparticle ◽  
Amine Groups ◽  
Positively Charged ◽  
Iron Palladium

Iron/palladium bimetallic nanoparticles (Fe/Pd NPs) are important catalytic materials for the field of environmental remediation. In the present study, filter paper was employed as a substrate for the assembly of Fe/Pd NPs and further applied for the catalytic conversion of hexavalent chromium Cr(VI) toward trivalent Cr(III). First, a filter paper with negative charge was assembled with a layer of positively charged polyethylenimine (PEI) through electrostatic interaction; then, the abundant amine groups of PEI were used to complex Fe(III) ions, followed by reduction via sodium borohydride to produce an Fe NP-assembled filter paper. Thereafter, the Fe/Pd NPs were produced by the reduction of PdCl42− through Fe NPs. The prepared filter paper assembled with Fe/Pd NPs with a mean diameter of 10.1 nm was characterized by various techniques. The Fe/Pd NP-assembled filter paper possesses powerful catalytic activity and can be used to transform Cr(VI) to Cr(III). With its low cost, high sustainability, and convenient industrialization potential, the developed approach may be extended to produce other bimetallic NP-immobilized filter paper for different environmental remediation applications.

scholarly journals Nanozyme-Participated Biosensing of Pesticides and Cholinesterases: A Critical Review

Biosensors ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 382
Author(s):  
Hengjia Zhu ◽  
Peng Liu ◽  
Lizhang Xu ◽  
Xin Li ◽  
Panwang Hu ◽  
...  
Keyword(s):  
Environmental Remediation ◽  
Low Cost ◽  
Catalytic Performance ◽  
Agricultural Products ◽  
Detection Methods ◽  
Highly Sensitive ◽  
Potential Applications ◽  
Highly Sensitive Detection ◽  
Excellent Stability

To improve the output and quality of agricultural products, pesticides are globally utilized as an efficient tool to protect crops from insects. However, given that most pesticides used are difficult to decompose, they inevitably remain in agricultural products and are further enriched into food chains and ecosystems, posing great threats to human health and the environment. Thus, developing efficient methods and tools to monitor pesticide residues and related biomarkers (acetylcholinesterase and butylcholinesterase) became quite significant. With the advantages of excellent stability, tailorable catalytic performance, low cost, and easy mass production, nanomaterials with enzyme-like properties (nanozymes) are extensively utilized in fields ranging from biomedicine to environmental remediation. Especially, with the catalytic nature to offer amplified signals for highly sensitive detection, nanozymes were finding potential applications in the sensing of various analytes, including pesticides and their biomarkers. To highlight the progress in this field, here the sensing principles of pesticides and cholinesterases based on nanozyme catalysis are definitively summarized, and emerging detection methods and technologies with the participation of nanozymes are critically discussed. Importantly, typical examples are introduced to reveal the promising use of nanozymes. Also, some challenges in the field and future trends are proposed, with the hope of inspiring more efforts to advance nanozyme-involved sensors for pesticides and cholinesterases.

Design of simple and efficient metal nanoparticles templated on ZnO-chitosan coated textile cotton towards the catalytic reduction of organic pollutants

2020 ◽  
pp. 152808372093148 ◽  
Author(s):  
Sher Bahadar Khan ◽  
Muhammad Ismail ◽  
Esraa M Bakhsh ◽  
Abdullah M Asiri
Keyword(s):  
Organic Pollutants ◽  
Catalytic Reduction ◽  
Low Cost ◽  
Significant Loss ◽  
Order Kinetic ◽  
X Rays ◽  
Highly Active ◽  
Nanocomposite Fibers ◽  
Uv Visible ◽  
Synthesis Procedure

In this study simple, facile and highly active silver coated ZnO-chitosan (Ag/ZnO-CH) textile cotton supported nanocomposites were developed. The nanocomposites were characterized by UV-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-rays spectroscopy (EDX), fourier transform infrared spectroscopy (FTIR) and X-rays diffraction (XRD). The prepared nanocomposite fibers were used for the selective removal of seven model pollutants, including para-nitrophenol (p-NP), meta-nitrophenol (m-NP), ortho-nitrophenol (o-NP), 2,4,6-trinitrophenol (TNP), and dyes of methyl orange (MO), congo red (CR), and methyl red (MR). The apparent rate constant (Kapp) of pseudo first order kinetic for p-NP was 2.813 × 10−3 s−1 and 1.663 × 10−3 s−1 for MO dye. Among the different nitroarenes, the reaction rate matched the ordered of p-NP >TNP > m-NP > o-NP, while for the dyes it was MO > CR > MR. Ag/ZnO-CH nanocomposites were recycled multiple times without any significant loss of its catalytic activity. The higher stability of the Ag/ZnO-CH nanofibers also allows the catalyst to be separated easily by just pulling the catalyst from the reaction mixture and reused. The clean and facile, simple synthesis procedure, outstanding properties and low-cost supports allow these catalysts to be used in the reduction of the organic pollutants individually as well as collectively in the mixture of dyes in wastewater at room temperature.

scholarly journals Facile Use of Silver Nanoparticles-Loaded Alumina/Silica in Nanofluid Formulations for Enhanced Catalytic Performance toward 4-Nitrophenol Reduction

2021 ◽  
Vol 18 (6) ◽  
pp. 2994
Author(s):  
Rashmi Mannu ◽  
Vaithinathan Karthikeyan ◽  
Murugendrappa Malalkere Veerappa ◽  
Vellaisamy A. L. Roy ◽  
Anantha-Iyengar Gopalan ◽  
...  
Keyword(s):  
Environmental Remediation ◽  
Catalytic Reduction ◽  
Catalytic Efficiency ◽  
Catalytic Performance ◽  
New Approach ◽  
Catalytic Rate Constant ◽  
Nitrophenol Reduction ◽  
Reduction Efficiency ◽  
Silver Nps ◽  
Ultrasonic Assisted

The introduction of toxic chemicals into the environment can result in water pollution leading to the degradation of biodiversity as well as human health. This study presents a new approach of using metal oxides (Al2O3 and SiO2) modified with a plasmonic metal (silver, Ag) nanoparticles (NPs)-based nanofluid (NF) formulation for environmental remediation purposes. Firstly, we prepared the Al2O3 and SiO2 NFs of different concentrations (0.2 to 2.0 weight %) by ultrasonic-assisted dispersion of Al2O3 and SiO2 NPs with water as the base fluid. The thermo-physical (viscosity, activation energy, and thermal conductivity), electrical (AC conductivity and dielectric constant) and physical (ultrasonic velocity, density, refractive index) and stability characteristics were comparatively evaluated. The Al2O3 and SiO2 NPs were then catalytically activated by loading silver NPs to obtain Al2O3/SiO2@Ag composite NPs. The catalytic reduction of 4-nitrophenol (4-NP) with Al2O3/SiO2@Ag based NFs was followed. The catalytic efficiency of Al2O3@Ag NF and SiO2@Ag NF, for the 4-NP catalysis, is compared. Based on the catalytic rate constant evaluation, the catalytic reduction efficiency for 4-NP is found to be superior for 2% weight Al2O3@Ag NF (92.9 × 10−3 s−1) as compared to the SiO2@Ag NF (29.3 × 10−3 s−1). Importantly, the enhanced catalytic efficiency of 2% weight Al2O3@Ag NF for 4-NP removal is much higher than other metal NPs based catalysts reported in the literature, signifying the importance of NF formulation-based catalysis.

Controllable growth of graphdiyne layered nanosheets for high-performance water oxidation

2021 ◽  
Author(s):  
Shuya Zhao ◽  
Yurui Xue ◽  
Zhongqiang Wang ◽  
Zhiqiang Zheng ◽  
Xiaoyu Luan ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
High Performance ◽  
Low Cost ◽  
Highly Active ◽  
Controllable Growth

Developing highly active, stable and low-cost electrocatalysts capable of an efficient oxygen evolution reaction (OER) is urgent and challenging.

Electrodeposited Ni-Fe-P-FeMnO3/Fe multi-stage nanostructured electrocatalyst with superior catalytic performance for water splitting

2021 ◽  
Author(s):  
Xiao Tan ◽  
Xin Liu ◽  
Yingying Si ◽  
Zunhang Lv ◽  
Zihan Li ◽  
...  
Keyword(s):  
Water Splitting ◽  
Alkaline Solution ◽  
Low Cost ◽  
Catalytic Performance ◽  
Multi Stage

It is very important to design and prepare low-cost and efficiency electrocatalysts for water splitting in alkaline solution. In this works, Ni-Fe-P and Ni-Fe-P-FeMnO3 electrocatalysts are developed using facile electrodeposition...

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