Novel metal modified diatomite, zeolite and carbon xerogel catalysts for mild conditions wet air oxidation of phenol

Significance 

Most of the industrial processes produce pollutant phenols. Interestingly, phenol is an intermediate product during the oxidation of aromatic hydrocarbons thus often present in wastewaters. Among the available wastewater treatment technologies, wet air oxidation (WAO) is suitable for high flow rate toxic contaminants and high organic loads. Unfortunately, despite minimal air pollution, its general safety implications and high capital cost limit its use.

Recently, catalytic wet air oxidation (CWAO) have been considered as a promising alternative amongst researchers owing to its effectiveness. For example, it minimizes the reaction severity and allows easier decomposition of pollutants resulting in low treatment costs. However, catalytic oxidation of phenol in mild condition has not been fully explored.

A group of researchers at Babeş-Bolyai University and Indiana University of Pennsylvania: Dr. Raluca Pleşa Chicinaş, Dr. Emese Gál, Dr. Horea Bedelean, Professor Mircea Darabantu and Dr. Andrada Măicăneanu performed catalytic wet air oxidation of phenol in aqueous solution using diatomite, zeolite and xerogel catalysts. Their work is published in the research journal, Separation and Purification Technology.

Briefly, the authors prepared metal modified diatomite and zeolite catalysts by impregnation while carbon xerogel catalyst was synthesized by sol-gel and ion exchange technique. They tested and investigated the efficiencies of the catalysts in catalytic wet air oxidation of phenol under low temperatures and ambient pressures. Furthermore, they also identified the reaction pathway for phenol oxidation.

Various metals were used in the preparation of catalysts and the results showed maximum efficiencies as 66%, 54% and 68% for Fe-D, Cu-Z and Co-CX catalysts respectively. Furthermore, for all the three catalysts, mineralization of phenol was dominant during the initial stages of the process. Small traces of oxalic, acetic and (di)carboxylic acids were identified as oxidation intermediate products. Additionally, was established that the kinetics for catalytic wet air oxidation of phenol follows a pseudo-first order model.

As a significant contribution of the study, the obtained results have qualitatively indicated the potential of using diatomite, zeolite and carbon xerogel to  prepare catalysts for catalytic wet air oxidation of phenol under mild conditions. They are generally low cost and quite simple to prepare except for carbon xerogels which involves some complex steps. Diatomite can be used as absorbent, catalyst as well as filtering material due to its high adsorption capacity, large surface area, chemical stability, and small particle size. On the other hand, natural zeolites and carbon materials like carbon xerogels also exhibit unique properties which have increased significant interest amongst researchers hence their choice for the study. Therefore, the authors are optimistic that the study will advance treatment of wastewaters.

Novel metal modified diatomite, zeolite and carbon xerogel catalysts for mild conditions wet air oxidation of phenol - Advances in Engineering

About the author

Eng. Raluca Corina PLEŞA CHICINAŞ, PhD

Born September 12th 1988.

Permanent position: Professor of Environmental Protection at ANA ASLAN Technical High School, Cluj-Napoca, Romania.

Professional development: Bachelor, 2011 (Environmental Protection and Engineereing in Industry, Technical University of Cluj-Napoca, Romania); Master, 2013 (Advanced Methods in Environmental Protection, Technical University of Cluj-Napoca, Romania); PhD, 2018 (Chemistry, BABES-BOLYAI University, Cluj-Napoca, Romania).

Interest: environmental protection, water depollution, industrial chemistry.

Skills: catalysts synthesis and characterization, catalytic wet air oxidation process, adsorption process.

E-mail: [email protected]

About the author

Emese GÁL, PhD

Born March 8th, 1981.

Permanent position: university PhD lecturer of Organic Chemistry at BABES-BOLYAI University, Department of Chemistry and Chemical Engineering Hungarian Line, Cluj-Napoca, Romania.

Professional development: Bachelor, 2003 (Chemistry and Physics, BABES-BOLYAI University, Cluj-Napoca, Romania); Master, 2004 (Advanced Organic Chemistry, BABES-BOLYAI University, Cluj-Napoca, Romania); PhD, 2010 (Chemistry, BABES-BOLYAI University, Cluj-Napoca, Romania); 2007-2008 analytical chemist (Gedeon Richter Pharmaceutical company). Post-Doc 2013 (BABES-BOLYAI University, Cluj-Napoca, Romania).

Interest: fine organic and heterocyclic stereo synthesis, analytical chemistry.

Skills: organic (iterative) synthesis, stereochemistry, spectroscopy.

Hobbies: gardening, metal and symphonic music, lecture Formula 1.

About the author

Horea BEDELEAN, PhD

Born December 27th, 1964.

Permanent position: university PhD Lecturer of Geology at BABES-BOLYAI University, Department of Geology, Cluj-Napoca, Romania.

Professional development: Bachelor, 1989, (Geology, BABES-BOLYAI University, Cluj-Napoca, Romania); PhD, 1999 (Geology, BABES-BOLYAI University, Cluj-Napoca, Romania);

Post-grad courses: Applied Computing Science (2003-2005).

Research interests: Mineralogical and petrographical researches on non-metalliferous industrial minerals: zeolites, clays, clay minerals, etc.; Studies on volcanic tuffs; Geological mapping of sedimentary formations.

Hobbies: photography, music.

E-mail: [email protected]

About the author

Eng. Mircea DARABANTU, PhD

Born June 6th, 1955.

Permanent position: full Professor of Organic Chemistry at BABES-BOLYAI University, Department of Chemistry, Cluj-Napoca, Romania.

Professional development: Bachelor, 1979 (Organic Chemical Technology, Polytechnic Institute TRAIAN VUIA Timisoara, Romania); PhD, 1994 (Chemistry, BABES-BOLYAI University, Cluj-Napoca, Romania); Post-Doc 1996-1997 (Florida Centre for Heterocyclic Compounds, University of Florida, Department of Chemistry, USA); Post-Doc 1999-2000 (Université de Caen, Institut de la Matière et du Rayonnement, Laboratoire de Chimie Moléculaire et Thio-organique, France); Habilitation à Diriger des Recherches 2005 (HDR, Chemistry, University of Rouen, France).

Awards: Chevalier de l’Ordre des Palmes Académiques, 2002 (Ministry of National Education of French Republic).

Interest: fine organic and heterocyclic stereosynthesis.

Skills: organic (iterative) synthesis, stereochemistry, spectroscopy.

Hobbies: cats, hard-rock, metal and (rock) symphonic music, lecture.

About the author

Eng. Sanda Andrada MAICANEANU, PhD

Born July 20th, 1971.

Tenure-track position: Assistant Professor of Physical Chemistry at Indiana University of Pennsylvania, Department of Chemistry, Indiana, PA, USA; Associate Professor of Chemical Engineering at BABES-BOLYAI University, Department of Chemical Engineering, Cluj-Napoca, Romania. Professional development: Bachelor of Science, 1994 (Chemical Engineering – Technology of Inorganic Substances, BABES-BOLYAI University, Cluj-Napoca, Romania); Master of Science, 1995 (Chemistry – Catalysis and Biocatalysis, BABES-BOLYAI University, Cluj-Napoca, Romania); PhD, 2002 (Materials Science, Cranfield University, United Kingdom); Post-Doc, Fulbright Scholarship, 2013-2014 (Chemistry and Materials Science, University of Connecticut, USA).

Interest: environmental chemistry, wastewater treatment.

Skills: undergraduate and graduate teaching, heterogeneous catalysts synthesis and characterization, development and testing of wastewater treatment processes (adsorption, ion exchange, WAO, AOP).

Hobbies: dogs, lecture, nature, hiking, macramé bracelets.

Reference

Pleşa Chicinaş, R., Gál, E., Bedelean, H., Darabantu, M., & Măicăneanu, A. (2018). Novel metal modified diatomite, zeolite and carbon xerogel catalysts for mild conditions wet air oxidation of phenol: Characterization, efficiency and reaction pathway. Separation and Purification Technology, 197, 36-46.

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