The past year has been a busy one for the SIMMET research group with a lot of activity on the conference, research and journal article fronts.
Conferences
On 30 August 2024 the group hosted Prof. Kersten Forsberg from the KTH University in Stockholm, Sweden and enjoyed the talk she presented on her group’s work on fractional crystallisation.
On Sunday 1 Sept the following members of the group travelled to Stellenbosch to take part in the Hydrometallurgy conference from 1-3 Sept 2024 at Stellenbosch:
Ms Paballo Pilane – poster presentation
Mr Ntuthuko Mbhamali – oral presentation
Mr David Nkhoesa – oral presentation
Dr Emmanuel Oke – poster presentation
Mr Lwazi Chuma – poster presentation
Dr Jos Nyembwe – poster presentation
Mr Craig Nsakabwebwe – poster presentation
Prof Herman Potgieter – session chair and part of the organising committee
Everyone enjoyed the conference, especially the conference dinner and the opportunity to forge new links with colleagues/peers having similar interests to themselves.
From 6-11 October 2024 the following members of the SIMMET group attended the Global Conference on Chemical Engineering (GCCE) in Cape Town:
Prof Lizelle van Dyk – main organiser of the conference and session chair for various sessions
Dr Darlington Ashiegbu – oral presentation and session chair
Mr Moeketsi Khomo – oral presentation
Prof Herman Potgieter – oral presentation and session chair
At the end of October 2024, Prof Herman Potgieter and Ms Ami Janse van Rensburg, a 4th year project student in the SIMMET group, travelled to the University of the Free State in Bloemfontein where Ami took part in the South African Academy of Arts and Science’s student symposium from 30-31 Oct 2025. At this conference students are required to present their work in Afrikaans. Ami did very well by obtaining the first prize in the category for Afrikaans second language speakers and coming third overall. Congratulations and well done Ami!
During 6-9 April 2025 Dr. Darlington Ashiegbu attended the 2nd International Conference on “Futuristic Materials for Sustainable Development Goals” at the Vaal University of Technology here he delivered a talk on the photocatalytic work done under his supervision in the group. Dr. Ashiegbu also attended the Materials Today Conference from 23-26 June 2025 in Sitges, Spain before he visited the University of Twente on 29 June 2025 by invitation from Prof Kasper Wenderich to deliver a talk on his research with photocatalytic compounds and their application to destroy contaminants in waste water.
General news
Mr Jochem Schuerman joined the SIMMET group in Jule 2024 from Twente University in the Netherlands for a six month internship and work on photocatalysts under the supervision of Dr Darlington Ashiegbu and Prof Potgieter. He returned to the University of Twente in December 2024 after completing a productive and highly successful project. His visit led to the establishment of new links with the group of his supervisor in the Netherlands, prof. Kasper Wenderlich, and a follow up visit by Dr Darlington Ashiegbu in June 2025 after attending a conference in Spain.
Mr Peter-Joe Combrinck submitted his M.Sc dissertation in December 2024, and left the group. His supervisors were Prof. Lizelle van Dyk and Prof. Herman Potgieter. Ms Samaneh Teimouri graduated with her Ph.D in Chemical Engineering in July 2024 and as a bonus published 5 papers from her work. Her supervisors were Prof. Caren Billing from the School of Chemistry at Wits and Prof. Herman Potgieter. Mr Moeketsi Khomo submitted his M.Sc dissertation in March 2025 for examination. His supervisors were (the late) Prof Henry Simonsen, Prof Lizelle van Dyk and Prof Herman Potgieter.
The following new students joined the group in the beginning of 2025:
Ms Pabalello Phatlhanyane – M. Sc. Chem Eng.
Ms Hannah Iyuke – M.Sc. Met Eng.
Mr Karabo Maoto – M.Sc. Chem Eng.
Mr Charles Chiponda – M.Sc. Chem Eng. Part-time.
Hanna’s project is on the extraction of Sc, Ta and Nb from ore originating from a mine in Brazil, while Karabo, Charles and Pabalello will develop the pioneering work of (the late) Prof Simonsen further to investigate the use of the jet-leach reactor configuration to extract gold from old tailings with various amino-acid and cyanide combinations.
Through some review work through the International Foundation of Science, Prof Potgieter and Dr Darlington Ashiegbu established contact with the group of Dr Dr. Akeem Rabiu at the Federal University of Health Sciences, Ila-Orangun, Nigeria, who is working on the destruction of harmful and toxic microorganisms in municipal household water. This led to a new collaboration to explore the potential application of photocatalysts to render water and wastewater safe and harmless for human consumption and contact.
Two of our group members left us in 2024 to pursue postdoctoral opportunities in Sweden. In April 2024, Samaneh Teimouri left to join the research group of Prof. Kersten Forsberg at KTH in Stockholm, Sweden. She was followed by Dr Jos Nyembwe in September 2024 to join the group of Prof. Christian Ekberg at the University of Gothenburg in Gothenburg, Sweden. While we missed them, we wish them success in their new environments.
In memorium
It was with great sadness that we learned in early May that Prof Henry Simonsen, a much loved and respected member of the SIMMET group, passed away unexpectedly shortly after leaving Wits at the end of April 2025 He made a huge impact on the research activities of the group since he joined Wits in 2016 as a visiting professor and his wisdom and experience will be sorely missed.
Trails and tribulations
Another stalwart of the group, Mr. Paul den Hoed, formally retired at the end of 2024, but will remain in an honorary/visiting capacity to continue assisting students in the group with their research. Paul sadly suffered a horrific hijacking attempt in early March and was quite badly injured in the process. Fortunately, he mended well and can now take good care of his wife, who recently had an operation on her hand. We wish their family a speedy and full recovery.
Publications
The members of the group were again very productive in 2024 and so far this year, and have produced the following journal publications (you should check what the rest have submitted here and combine everything, please):
2024
- E. Oke and J.H. Potgieter, Discarded E-Waste/Printed Circuit Boards: A Review of their Recent Methods of Disassembly, Sorting and Environmental Implications. Journal of Material Cycles and Waste Management, 2024 (in print)
https://doi.org/10.1007/s10163-024-01917-7
- H. Simonsen, J. H. Potgieter, K. J. Nyembwe and A. Chuma, Can preconcentration of cassiterite from its pegmatite ore reduce processing costs and improve operational sustainability?, Journal of the Southern African Institute of Mining and Metallurgy, 2024 (in print)
- Investigating aging processes and characterization of nanodispersed Cu-Al layered double hydroxides produced by non-equilibrium electrochemical oxidation, Polyhedron, 2024 (in print)
- E. Oke and J.H. Potgieter, Recent Chemical Methods for Metal Recovery from Printed Circuit Boards: A Review, Journal of Material Cycles and Waste Management, 2024 (in print)
- Emmanuel A. Oke, Herman Potgieter, Fortune Mondlane, Noluthando P. Skosana, Samaneh Teimouri and Joseph K. Nyembwe, Concurrent leaching of copper and cobalt from a copper–cobalt ore using sulfuric and organic acids, Minerals Engineering, 216 (2024) 108853 https://doi.org/10.1016/j.mineng.2024.108853
- Darlington Ashiegbu, David Nkhoesa, Rudolph Erasmus, Herman Johannes Potgieter
Efficient Photodegradation of Thiocyanate Ions in Mining Wastewater Using a ZnO-BiOI Heterojunction , Materials, 2024, in press
- Natalia V. Usoltseva, Johannes H. Potgieter, Vladimir V. An, Baodan Liu, Sergey A. Stepanov, Damir T. Valiev, Investigating aging processes and characterization of nanodispersed Cu-Al layered double hydroxides produced by non-equilibrium electrochemical oxidation Polyhedron, 253 (2024) 116927
- Kakhramon Rakhimbekov, Johannes Potgieter, Damir Valiev, Vladimir An, Anna Blinova, Natalia Usoltseva, Alexey Pustovalov, Maksim Vasilevichev, Alexandra Platonova, Sergey Stepanov, Dmitri Kokotov, Vladimir SypchenkoS, WS2-ZnO nanostructures for photoelectrochemical hydrogen generation, ACS Applied Energy Materials, 2024, 7, 9756−9765. https://doi.org/10.1021/acsaem.4c01488
2025
- David Whitefield, Vivian Motsumi; Herman Potgieter, Wear Properties of Different Grades of High-Cr White Cast Irons for Chute Linings, Journal: Journal of Engineering and Applied Science, resubmitted
- Teimouri, C. Billing and J.H. Potgieter, A Comparison of the Electrochemical Oxidative Dissolution of Pyrite and Chalcopyrite in Dilute Nitric Acid Solution, ChemistryOpen, 2025, doi.org/10.1002/open.202400053 (2025)
- Darlington C Ashiegbu, Paballo Pilane, John Moma, Herman Johanes Potgieter, Enhanced Photocatalytic Degradation of Cyanide in Mining Wastewater
Using a ZnO-based Heterojunction Catalyst, Surfaces, 2025, 8, 3. https://doi.org/
10.3390/surfaces8010003 (2025)
4. Kheswa, B.S.; Whitefield, D.; Potgieter, H.; Bodunrin, M. Corrosion Behaviour of S32101(1.4162—X2CrMnNiN21-1-1) Stainless Steel in Pulping Liquors. Materials, 2025, 18, 1921. https://doi.org/10.3390/ma18091921
- E. Oke and J.H. Potgieter, Sustainable Leaching of Metals from Waste Printed Circuit Boards using Efficient Carboxylic Acid-Based Deep Eutectic Solvents, Separation and Purification Technology, 374 (2025) 133712
- Emmanuel Anuoluwapo Oke, Johannes Hermanus Potgieter. Effectiveness of Acidic Deep Eutectic Solvents in Recovery of Hazardous Base Metals from Waste Printed Circuit Boards, Environmental Science and Pollution Research – https://doi.org/10.1007/s11356-025-36685-w (2025)
- Darlington C. Ashiegbu, Michael Enemuo and Herman Potgieter, Efficient Degradation of Organic and Inorganic Contaminants in Water Using a ZnO-based Heterojunction Photocatalyst, European Journal of Materials, Vol. 5, no. 1, 2536462 (2025)
https://doi.org/10.1080/26889277.2025.2536462
- Darlington Ashiegbu, Yusuf Makarfi Isa, Herman Potgieter and Ifeanyi Michael Smarte Anekwe, Circular economy and energy transition: a review of South Africa’s 5-year just energy transition investment plan (JET-IP), · Mitig Adapt Strateg Glob Change, 30:48 (2025) https://doi.org/10.1007/s11027-025-10230-z