Preparation of eco-friendly nanocomposites based on immobilization of magnetic activated carbon with tartaric acid: Application for adsorption of heavy metals and evaluation of their catalytic activity in C-C coupling reaction

2022 ◽  
Vol 277 ◽  
pp. 115591
Author(s):  
Fatemeh Maghsoodi Goushki ◽  
Mohammad Reza Islami ◽  
Vajihe Nejadshafiee
2018 ◽  
Vol 40 (12) ◽  
pp. 1761-1776 ◽  
Author(s):  
Van Thuan Le ◽  
Thi Kieu Ngan Tran ◽  
Dai Lam Tran ◽  
Hoang Sinh Le ◽  
Van Dat Doan ◽  
...  

2021 ◽  
Vol 11 (11) ◽  
pp. 4822
Author(s):  
Hamed M. Alshammari ◽  
Obaid F. Aldosari ◽  
Mohammad Hayal Alotaibi ◽  
Raja L. Alotaibi ◽  
Mosaed S. Alhumaimess ◽  
...  

Palladium-based carbon catalysts (Pd/C) can be potentially applied as an efficient catalyst for Suzuki–Miyaura and Mizoroki–Heck coupling reactions. Herein, a variety of catalysts of palladium on activated carbon were prepared by varying the content of ‘Pd’ via an in situ reduction method, using hydrogen as a reducing agent. The as-prepared catalysts (0.5 wt % Pd/C, 1 wt % Pd/C, 2 wt % Pd/C and 3 wt % Pd/C) were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Brunauer–Emmett–Teller (BET) analyses. The catalysts were tested as a coupling catalyst for Suzuki–Miyaura coupling reactions involving aryl halides and phenyl boronic acid. The optimization of the catalyst by varying the palladium content on the activated carbon yielded Pd/C catalysts with very high catalytic activity for Suzuki reactions of aryl halides and a Mizoroki–Heck cross-coupling reaction of 4-bromoanisol and acrylic acid in an aqueous medium. A high ‘Pd’ content and uniform ‘Pd’ impregnation significantly affected the activity of the catalysts. The catalytic activity of 3% Pd/C was found to make it a more efficient catalyst when compared with the other synthesized Pd/C catalysts. Furthermore, the catalyst reusability was also tested for Suzuki reactions by repeatedly performing the same reaction using the recovered catalyst. The 3% Pd/C catalyst displayed better reusability even after several reactions.


Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 841
Author(s):  
Marina Burachevskaya ◽  
Saglara Mandzhieva ◽  
Tatiana Bauer ◽  
Tatiana Minkina ◽  
Vishnu Rajput ◽  
...  

The presence of heavy metals in the soil could impose serious problems on soil-plant systems due to the accumulation of heavy metals in plants. Even vital elements such as Cu and Zn have a toxic effect in the case of excessive intake by living organisms. The present work aimed to investigate the content of loosely bound (exchangeable, complexed, and specifically sorbed) compounds of Cu and Zn and their availability to spring barley (Hordeum sativum distichum) in contaminated Haplic Chernozem soil under the conditions of a model experiment (five approximate permissible concentrations (APC) and 10 APC of metal). Changes in the bioavailability of the metals upon application of carbon sorbents were observed. An increase in loosely bound metal compounds has been shown under conditions of soil contamination with metals (up to 57% of the total content). The increase in the availability of Cu in the soil was mainly due to the formation of complexed metal forms with organic matter (up to 17%). The availability of Zn was found to be associated with an increase in exchangeable (up to 21%) and specifically sorbed compounds (up to 27%). Granular activated carbon (GAC) and biochar have high sorption properties. A decrease in the content of loosely bound compounds of metals was established, especially in the most mobile forms such as exchangeable and complexed forms. The introduction of sorbents into the soil opened up a new venue for binding heavy metals in situ, eventually leading to a decrease in their bioavailability. The inactivation of Cu and Zn in the soil upon the application of sorbents led to a decrease in metal absorption by spring barley. The highest efficiency of biochar application was established at a dose of 2.5% and 5% in soil contaminations of 5 APC and 10 APC of Cu or Zn. The efficiency of the use of sorbents was more influenced by the dose of application than by the type of sorbent. There was no significant difference between biochar and GAC. Stabilization and inactivation of metals may improve soil fertility and plant growth.


2021 ◽  
Author(s):  
Petar Djinović ◽  
Janez Zavašnik ◽  
Janvit Teržan ◽  
Ivan Jerman

AbstractCeO2, V2O5 and CeVO4 were synthesised as bulk oxides, or deposited over activated carbon, characterized by XRD, HRTEM, CO2-TPO, C3H8-TPR, DRIFTS and Raman techniques and tested in propane oxidative dehydrogenation using CO2. Complete oxidation of propane to CO and CO2 is favoured by lattice oxygen of CeO2. The temperature programmed experiments show the ~ 4 nm AC supported CeO2 crystallites become more susceptible to reduction by propane, but less prone to re-oxidation with CO2 compared to bulk CeO2. Catalytic activity of CeVO4/AC catalysts requires a 1–2 nm amorphous CeVO4 layer. During reaction, the amorphous CeVO4 layer crystallises and several atomic layers of carbon cover the CeVO4 surface, resulting in deactivation. During reaction, V2O5 is irreversibly reduced to V2O3. The lattice oxygen in bulk V2O5 favours catalytic activity and propene selectivity. Bulk V2O3 promotes only propane cracking with no propene selectivity. In VOx/AC materials, vanadium carbide is the catalytically active phase. Propane dehydrogenation over VC proceeds via chemisorbed oxygen species originating from the dissociated CO2. Graphic Abstract


Chemosphere ◽  
2022 ◽  
Vol 287 ◽  
pp. 132085
Author(s):  
Prajwal Sherugar ◽  
Mahesh Padaki ◽  
Nagaraj S. Naik ◽  
Sajan D. George ◽  
Dharmapura H.K. Murthy

2014 ◽  
Vol 50 (82) ◽  
pp. 12356-12359 ◽  
Author(s):  
Baocang Liu ◽  
Yuefang Niu ◽  
Yan Li ◽  
Fan Yang ◽  
Jiamin Guo ◽  
...  

A novel mesoporous “shell-in-shell” structured nanoreactor (@Pd/meso-TiO2/Pd@meso-SiO2) shows superior catalytic activity, stability, and selectivity for Suzuki–Miyaura coupling reaction.


Sign in / Sign up

Export Citation Format

Share Document