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Recent Advances Utilized in the Recycling of Catalysts II

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A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Environmental Catalysis".

Deadline for manuscript submissions: closed (30 April 2023) | Viewed by 6833

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Special Issue Editor

Dr. Katarzyna Staszak

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Guest Editor

Institute of Chemical Technology and Engineering, Poznan University of Technology, Berdychowo St. 4, 60-965 Poznan, Poland
Interests: separations; metal recovery; membrane techniques; adsorption; surfactants
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue is a continuation of a previous Special Issue, “Recent Advances Utilized in the Recycling of Catalysts”.

The choice of topic of Special Issue is not accidental. The idea came up during the unceasing research of potential secondary sources of metals, as well as methods for their recovery.

Catalytic processes are widely used in the industry. In addition to the undeniable benefits of their application, it should be remembered that their use is time-limited. The industry generates thousands of tons per year of spent catalysts containing valuable, but usually hazardous, metals, such as the platinum-group metals (PGMs), rare-earth elements (REEs), and a variety of transition metals. Thus, the spent catalysts can be considered as the secondary source of metals. Today, the recovery of raw materials from waste sources is not only an ecological idea, but it is the overarching goal of the zero-waste economy.

This Special Issue is a collection of suitable research articles related to the recent methods of metal reclamation from spent catalysts.

Dr. Katarzyna Staszak
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Catalysts is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

spent catalysts
recycling
metal recovery
wastes to value-added products
zero waste economy

Published Papers (3 papers)

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Research

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14 pages, 1257 KiB

Open AccessFeature PaperArticle

Waste-to-Resources: Leaching of Cobalt from Spent Cobalt Oxide Catalyst

by Dominika Małolepsza, Martyna Rzelewska-Piekut, Magdalena Emmons-Burzyńska and Magdalena Regel-Rosocka

Catalysts 2023, 13(6), 952; https://doi.org/10.3390/catal13060952 - 31 May 2023

Viewed by 1339

Abstract

This article presents studies on the recovery of cobalt from a spent cobalt oxide catalyst, left after the preparation of industrial catalysts. Apart from cobalt, the tested material contained iron, copper, zinc, and nickel. Leaching was proposed as a simple and feasible operation to treat the spent cobalt oxide. The 0.1–8.0 M H₂SO₄ solutions were applied as leaching agents at an ambient temperature and at 70 °C. An 8.0 M H₂SO₄ solution at 70 °C leached two-fold more Co(II) than a 0.1 M H₂SO₄ solution at the same temperature. Similar to Co(II), regardless of the leaching temperature, the Fe ion was leached more efficiently with 4.0 or 8.0 M H₂SO₄ than with a 0.1 M acid. It should be emphasized that the Co(II) content in the solution after leaching was predominant at >90% (~4800 mg/dm³), compared to other metal ions. The ANOVA analysis indicated that both the sulfuric(VI) acid concentration and temperature had a significant effect on the leaching efficiency. An increase in acid concentration from 0.1 to 8 M and the temperature of leaching (from ambient to 70 °C) had a positive effect on the Co leaching efficiency (an increase from ~20 to almost 50%). The proposed hydrometallurgical treatment of the spent cobalt oxide catalyst is a response to the waste-to-resource (WTR) approach. Full article

(This article belongs to the Special Issue Recent Advances Utilized in the Recycling of Catalysts II)

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Review

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18 pages, 2124 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Recent Advances in Platinum and Palladium Solvent Extraction from Real Leaching Solutions of Spent Catalysts

by Ana Paula Paiva

Catalysts 2023, 13(7), 1146; https://doi.org/10.3390/catal13071146 - 24 Jul 2023

Cited by 2 | Viewed by 2101

Abstract

The strategic importance of platinum and palladium, two platinum-group metals (PGMs), is particularly supported by their technological applications, one of the most relevant being the role they perform as catalysts for several sorts of chemical reactions. The cumulative demand for these two PGMs to be used as catalysts more than justifies increasing research efforts to develop sustainable recycling processes to maintain their supply. This critically appraised topic review describes the recent research trends (since 2010) developed by the world’s research communities to reach sustainable methods to recover platinum and palladium from spent catalysts in the liquid phase, namely those involving a solvent extraction (SX) step. The selected recycling processes are based on extensive fundamental research, but this paper intends to focus on information collected about SX procedures applied to real leaching samples of spent catalysts, either from automobile or industrial sources. A critical appraisal of the claimed success levels, the identified constraints, and open challenges is carried out, together with some perspectives on possible ways to redirect research efforts and minimize the gap between academia and industry on this matter. Full article

(This article belongs to the Special Issue Recent Advances Utilized in the Recycling of Catalysts II)

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24 pages, 2564 KiB

Open AccessFeature PaperReview

Environmentally Benign Nanoparticles for the Photocatalytic Degradation of Pharmaceutical Drugs

by Farah Quddus, Afzal Shah, Faiza Jan Iftikhar, Noor Samad Shah and Abdul Haleem

Catalysts 2023, 13(3), 511; https://doi.org/10.3390/catal13030511 - 02 Mar 2023

Cited by 7 | Viewed by 3012

Abstract

A rapid rise in industrialization has led to the release of pharmaceutical pollutants into water bodies, rendering water inappropriate for consumption by humans and animals, challenging our efforts to achieve the clean water sustainable development goal. These pharmaceutical pollutants include antibiotics, anticancer drugs, antidepressants, etc., which are highly stable and persistent in water, in addition to being harmful to life. At times, the secondary pollutant that is formed after degradation is more potent than the parent drug. Conventional water purification methods cannot completely remove these pollutants. Hence, efficient and robust methods are required to degrade pharmaceutical waste. Photocatalytic degradation of drugs is deemed an efficient and effective method for environmental remediation, along with recovery of photocatalysts, which are important for recycling and sustainable use. Herein, we present the synthesis of nanoparticles (NPs) and their application for photocatalytic degradation of pharmaceutical waste as a preferred water treatment method. Additionally, green synthesis of photocatalytic nanomaterials offers the benefit of avoiding secondary pollution. The green synthesis of NPs is employed by using plant extracts that offer a number of metabolites as reducing agents or capping agents, as well as the use of microbes as green nanofactories to tackle the issue of water cleanliness with respect to pharmaceutical waste. Despite regulations concerning drug disposal, some underdeveloped countries do not enforce and practice these guidelines in letter and spirit. Hence, the current work presenting a promising water cleanliness method is expected to contribute to the assurance of strict policy compliance and enforcement, resulting in the resolution of the health concerns with respect to hazardous pharmaceutical waste disposal in water bodies. Full article

(This article belongs to the Special Issue Recent Advances Utilized in the Recycling of Catalysts II)

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