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12 Results Found

  • Article
  • Open Access
8 Citations
4,888 Views
16 Pages

15 December 2022

Increases in biodiesel prices remains a challenge, mainly due to the high cost of conventional oil feedstocks used during biodiesel production and the challenges associated with using homogeneous catalysts in the process. This study investigated the...

(This article belongs to the Section Environmental Catalysis)
  • Article
  • Open Access
15 Citations
2,665 Views
16 Pages

Fusion-Assisted Hydrothermal Synthesis of Technogenic-Waste-Derived Zeolites and Nanocomposites: Synthesis, Characterization, and Mercury (II) Adsorption

  • Madina Suleimenova,
  • Saule Zharylkan,
  • Meruyert Mekenova,
  • Alibek Mutushev and ,
  • Seytkhan Azat,
  • Aidana Tolepova,
  • Alzhan Baimenov,
  • Aliya Satayeva and
  • Zhandos Tauanov
  • + 4 authors+ 0 author

This study presents the synthesis of zeolites derived from coal fly ash (CFA) using the fusion-assisted alkaline hydrothermal method. The zeolites were synthesized by combining CFA and NaOH at a molar ratio of 1:1.2 under fusion temperatures of 500,...

(This article belongs to the Section Molecular Nanoscience)
  • Article
  • Open Access
29 Citations
5,178 Views
14 Pages

26 November 2019

Traditional hydrothermal method (TH) and alkali fusion-assisted hydrothermal method (AFH) were evaluated for the preparation of zeolites from waste basalt powder by using NaOH as the activation reagent in this study. The synthesized products were cha...

(This article belongs to the Section Porous Materials)
  • Article
  • Open Access
5 Citations
1,999 Views
18 Pages

31 October 2025

Fly ash from coal-fired power plants is a promising precursor for zeolite synthesis due to its aluminosilicate-rich composition. However, its direct utilization is often limited by impurities and a low silicon-to-aluminum ratio (SAR). This study demo...

(This article belongs to the Special Issue Coal Fly Ash as a Resource: Advances in Characterization, Utilization and Sustainable Solutions)
  • Proceeding Paper
  • Open Access
1,615 Views
3 Pages

Effect of Milling Time on the Sensing Properties of Fly Ash Zeolite Composite Thin Films

  • Katerina Lazarova,
  • Silviya Boycheva,
  • Marina Vasileva,
  • Denitza Zgureva and
  • Tsvetanka Babeva

Thin films, consisting of a sol–gel Nb2O5 matrix doped with zeolite Na-X synthesized from fly ash through ultrasonic-assisted double-stage fusion-hydrothermal alkaline activation, were deposited by the spin-coating method. In order to improve the opt...

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)
  • Article
  • Open Access
9 Citations
3,879 Views
11 Pages

20 October 2020

The synthesis of zeolites using waste as a source of Si and Al is well known, and light coal ash has been studied to minimize the problems of waste management and mitigate environmental effects. The residue used in this work was supplied by Coal Work...

(This article belongs to the Special Issue Molecular Sieves: Synthesis, Characterization and Application (Concerning to the 6th Cycle of Lectures on Molecular Sieves))
  • Article
  • Open Access
2,713 Views
17 Pages

Acetone-Sensitive Thin Films Comprising Coal Fly Ash Na-X Zeolites and Sol–Gel Nb2O5 Matrix

  • Katerina Lazarova,
  • Silviya Boycheva,
  • Marina Vasileva,
  • Denitza Zgureva-Filipova and ,
  • Biliana Georgieva and
  • Tsvetanka Babeva
  • + 1 author+ 0 author

15 September 2021

In this study, thin composite films of a sol–gel Nb2O5 matrix doped with coal fly ash Na-X zeolites were deposited by the spin-coating method. Fly ash of lignite coal collected from the electrostatic precipitators of one of the biggest TPPs in Bulgar...

  • Article
  • Open Access
3 Citations
2,353 Views
18 Pages

The Formation of γ-Valerolactone from Renewable Levulinic Acid over Ni-Cu Fly Ash Zeolite Catalysts

  • Margarita Popova,
  • Silviya Boycheva,
  • Ivan Dimitrov,
  • Momtchil Dimitrov and ,
  • Daniela Kovacheva,
  • Daniela Karashanova,
  • Nikolay Velinov,
  • Genoveva Atanasova and
  • Agnes Szegedi
  • + 4 authors+ 0 author

5 December 2024

Zeolites with different structures (P1, sodalite, and X) were synthesized from coal fly ash by applying ultrasonically assisted hydrothermal and fusion–hydrothermal synthesis. Bimetallic catalysts, containing 5 wt.% Ni and 2.5 wt.% Cu, supporte...

(This article belongs to the Section Materials Chemistry)
  • Feature Paper
  • Article
  • Open Access
21 Citations
4,841 Views
19 Pages

Studies on the Potential of Nonmodified and Metal Oxide-Modified Coal Fly Ash Zeolites For Adsorption of Heavy Metals and Catalytic Degradation of Organics for Waste Water Recovery

  • Silviya Boycheva,
  • Denitza Zgureva,
  • Simona Miteva,
  • Ivan Marinov and ,
  • Dominika Marcin Behunová,
  • Ivalina Trendafilova,
  • Margarita Popova and
  • Miroslava Václaviková
  • + 3 authors+ 0 author

3 July 2020

A nanocrystalline zeolite of Na-X type (CFAZ) was synthesized by ultrasonic-assisted double stage fusion-hydrothermal alkaline conversion of lignite coal fly ash. Modified CFAZ with magnetic nanoparticles (MNP-CFAZ) was obtained by adding presynthesi...

(This article belongs to the Special Issue Sustainable Remediation Processes Based on Zeolites)
  • Review
  • Open Access
257 Views
50 Pages

16 October 2026

Zeolite-P is a synthetic member of the gismondine (GIS) framework family and is intrinsically microporous, with intersecting eight-membered-ring channels. Mesoporosity reported for some Zeolite-P samples is therefore a secondary textural feature aris...

  • Feature Paper
  • Article
  • Open Access
6 Citations
3,317 Views
22 Pages

3D Printed Ni–Cu Sodalite Catalysts for Sustainable γ-Valerolactone Production from Levulinic Acid—Effect of the Copper Content and the Method of Preparation

  • Margarita Popova,
  • Boian Mladenov,
  • Ivan Dimitrov,
  • Momtchil Dimitrov and ,
  • Violeta Mitova,
  • Yavor Mitrev,
  • Daniela Kovacheva,
  • Nikolay Velinov,
  • Daniela Karashanova and
  • Silviya Boycheva
  • + 5 authors+ 0 author

1 January 2025

Coal fly ash zeolites with Sodalite structure were synthesized by ultrasound-assisted double stage fusion-hydrothermal synthesis. Monometallic Ni and bimetallic Ni–Cu supported catalysts with 5 wt.% Ni and different copper contents of 1.5, 2.5...

(This article belongs to the Special Issue Preparation, Characterization and Application of Heterogeneous Catalysts)
  • Article
  • Open Access
403 Views
27 Pages

12 July 2026

Waste aluminum dust generated from aluminum refining and machining processes contains high fractions of Al2O3 and SiO2, making it a potential secondary aluminosilicate resource for zeolite synthesis. In this study, waste aluminum dust was converted i...

(This article belongs to the Section Extractive Metallurgy)