Analysis of the role of citric acid in the preparation of highly active HDS catalysts

Novel Cu–Ce–Zr mixed oxides were synthesized by a citric acid sol–gel method, and they exhibited an excellent NH3-SCO activity (180 °C, TOF = 1.33 h−1).

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Phytoextraction of Lead Using a Hedge Plant [Alternanthera bettzickiana (Regel) G. Nicholson]: Physiological and Biochemical Alterations through Bioresource Management

Sustainability ◽

10.3390/su13095074 ◽

2021 ◽

Vol 13 (9) ◽

pp. 5074

Author(s):

Urooj Kanwal ◽

Muhammad Ibrahim ◽

Farhat Abbas ◽

Muhammad Yamin ◽

Fariha Jabeen ◽

...

Keyword(s):

Citric Acid ◽

Growth Parameters ◽

Cost Effective ◽

Dry Weight ◽

Citric Acid Concentration ◽

Biochemical Alterations ◽

Biomass Plant ◽

Environmentally Friendly Approach ◽

Pb Concentration

Phytoremediation is a cost-effective and environmentally friendly approach that can be used for the remediation of metals in polluted soil. This study used a hedge plant–calico (Alternanthera bettzickiana (Regel) G. Nicholson) to determine the role of citric acid in lead (Pb) phytoremediation by exposing it to different concentrations of Pb (0, 200, 500, and 1000 mg kg−1) as well as in a combination with citric acid concentration (0, 250, 500 µM). The analysis of variance was applied on results for significant effects of the independent variables on the dependent variables using SPSS (ver10). According to the results, maximum Pb concentration was measured in the upper parts of the plant. An increase in dry weight biomass, plant growth parameters, and photosynthetic contents was observed with the increase of Pb application (200 mg kg−1) in soil while a reduced growth was experienced at higher Pb concentration (1000 mg kg−1). The antioxidant enzymatic activities like superoxide dismutase (SOD) and peroxidase (POD) were enhanced under lower Pb concentration (200, 500 mg kg−1), whereas the reduction occurred at greater metal concentration Pb (1000 mg kg−1). There was a usual reduction in electrolyte leakage (EL) at lower Pb concentration (200, 500 mg kg−1), whereas EL increased at maximum Pb concentration (1000 mg kg−1). We concluded that this hedge plant, A. Bettzickiana, has the greater ability to remediate polluted soils aided with citric acid application.

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The role of JrPPOs in the browning of walnut explants

BMC Plant Biology ◽

10.1186/s12870-020-02768-8 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Shugang Zhao ◽

Hongxia Wang ◽

Kai Liu ◽

Linqing Li ◽

Jinbing Yang ◽

...

Keyword(s):

Tissue Culture ◽

Production Efficiency ◽

Phenolic Content ◽

Leaf Tissue ◽

Limiting Factor ◽

Mature Leaves ◽

Survival Percentage ◽

Highly Active ◽

Young Leaves

Abstract Background Tissue culture is an effective method for the rapid breeding of seedlings and improving production efficiency, but explant browning is a key limiting factor of walnut tissue culture. Specifically, the polymerization of PPO-derived quinones that cause explant browning of walnut is not well understood. This study investigated explants of ‘Zanmei’ walnut shoot apices cultured in agar (A) or vermiculite (V) media, and the survival percentage, changes in phenolic content, POD and PPO activity, and JrPPO expression in explants were studied to determine the role of PPO in the browning of walnut explants. Results The results showed that the V media greatly reduced the death rate of explants, and 89.9 and 38.7% of the explants cultured in V media and A media survived, respectively. Compared with that of explants at 0 h, the PPO of explants cultured in A was highly active throughout the culture, but activity in those cultured in V remained low. The phenolic level of explants cultured in A increased significantly at 72 h but subsequently declined, and the content in the explants cultured in V increased to a high level only at 144 h. The POD in explants cultured in V showed high activity that did not cause browning. Gene expression assays showed that the expression of JrPPO1 was downregulated in explants cultured in both A and V. However, the expression of JrPPO2 was upregulated in explants cultured in A throughout the culture and upregulated in V at 144 h. JrPPO expression analyses in different tissues showed that JrPPO1 was highly expressed in stems, young leaves, mature leaves, catkins, pistils, and hulls, and JrPPO2 was highly expressed in mature leaves and pistils. Moreover, browning assays showed that both explants in A and leaf tissue exhibited high JrPPO2 activity. Conclusion The rapid increase in phenolic content caused the browning and death of explants. V media delayed the rapid accumulation of phenolic compounds in walnut explants in the short term, which significantly decreased explants mortality. The results suggest that JrPPO2 plays a key role in the oxidation of phenols in explants after branch injury.

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New Insights on CO and CO2 Hydrogenation for Methanol Synthesis: the Key Role of Adsorbate-adsorbate Interactions on Cu and the Highly Active MgO-Cu Interface

Journal of Catalysis ◽

10.1016/j.jcat.2021.06.020 ◽

2021 ◽

Author(s):

Ang Cao ◽

Zhenbin Wang ◽

Hao Li ◽

Ahmed O. Elnabawy ◽

Jens K. Nørskov

Keyword(s):

Methanol Synthesis ◽

Co2 Hydrogenation ◽

Highly Active ◽

Co And Co2 Hydrogenation

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MCM-41 grafted with citric acid: The role of carboxylic groups in enhancing the synthesis of xanthenes and removal of heavy metal ions

Environmental Nanotechnology Monitoring & Management ◽

10.1016/j.enmm.2020.100410 ◽

2021 ◽

Vol 15 ◽

pp. 100410

Author(s):

Mohammed A. Mannaa ◽

Hatem M. Altass ◽

Reda S. Salama

Keyword(s):

Heavy Metal ◽

Citric Acid ◽

Metal Ions ◽

Heavy Metal Ions ◽

Carboxylic Groups ◽

Mcm 41

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A Mini Review on Doped Nickel-Based Electrocatalysts for Hydrogen Evolution Reaction

Energies ◽

10.3390/en13184651 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4651

Author(s):

Yilin Deng ◽

Wei Lai ◽

Bin Xu

Keyword(s):

Hydrogen Evolution ◽

Hydrogen Evolution Reaction ◽

Water Electrolysis ◽

Energy Resources ◽

Alkaline Media ◽

Hydrogen Energy ◽

Heteroatom Doping ◽

Highly Active ◽

Production Of Hydrogen

The energy crisis and environmental pollution have attracted much attention and have promoted researches on clean and sustainable hydrogen energy resources. With the help of highly active and stable transition metal nickel-based catalysts, the production of hydrogen from water electrolysis from electrolyzed water has become an inexpensive and efficient strategy for generating hydrogen energy. In recent years, heteroatom doping has been found to be an effective strategy to improve the electrocatalytic hydrogen evolution reaction (HER) performances of nickel-based catalysts in acidic, neutral, and alkaline media. This review will highlight many recent works of inexpensive and readily available heteroatom-doped nickel-based HER catalysts. The evaluation methods for the performances of HER catalyst will be briefly described, and the role of heteroatom doping and its application in nickel-based catalyst will be summarized. This article will also point out some heteroatom doping strategies, which may provide references and inspire the design of other catalysts with dopants.

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