Chemical and Materials Engineering

Project

The mechanical properties of individual spray-dried milk powders can have a significant effect on its particulate properties, including flowability, packing density, and the quality of the final product. This project requires the student to be present in-person in Auckland during the summer of 2023-24 to perform nanoindentation in the nanomechanical research laboratory in order to characterise the hardness and Young’s modulus of pure whey protein powder, lactose powder, skim milk powder, and full cream milk powder. These properties can then be related to the bulk particle properties of the milk powders.

Project

Current fruit drying process monitoring methods are manual, invasive, and lack real-time data, leading to time-consuming tasks and potential quality degradation. Subjective bias from visual assessments risks inaccurate quality control. These methods primarily track existing conditions, offering limited predictive capability for future fruit quality variable changes such as colour and moisture content. To overcome these challenges and assure product quality, a predictive, non-invasive, real-time soft sensor using machine learning techniques is needed.

There are two main objectives of this project:
1) To develop a soft sensor capable of continuously monitoring fruit during the drying process and predicting quality variable changes such as colour, shape shrinkage, and moisture content.
2) To develop and validate machine learning models to correlate the image analysis results with key quality variable changes of drying fruit.

Skills required:
Proficiency in Matlab and/or Python, mathematical modelling and/or data analysis

Project

Phosphorus is a key element that causes water eutrophication, whose trigger threshold concentration can be as low as 0.01mg/L. About one-third of the world's freshwater has eutrophication potential caused by excessive phosphorus. Under the premise that the carbon and nitrogen of have been relatively well controlled, low concentration of phosphorus is the key factor causing such eutrophication. Current phosphorus treatment in urban waters is essentially the internal transfer of phosphorus between different media (e.g water-sediment-plant or water-sediment-adsorbent), and has not been truly removed from the water system, there is still a lack of sufficient attention to the long-term stable removal and in-situ control of low-concentration phosphorus in urban waters.

The objectives of this research are:
1) To understand the occurrence and transformation mechanism of difference phosphorus species in a range of small urban water bodies

2) To develop carbon-based and metal-based, robust adsorbents for phosphorus removal and recovery specifically tailored for low phosphorus concentrations in typical urban

Skills required:
Chemical and Materials Engineering UG students.

Project

Excess sludge formation during wastewater treatment poses a challenge to the operation efficiency due to the risk of overflow. Furthermore, sludge disposal is quite costly. Consequently, a new wastewater treatment process has been developed that uses hydrogel beads as a bio-carrier to protect and encourage the growth of bacteria within the gel`s porous network. The network provides a vast surface area, allowing bacteria to grow more efficiently. The high porosity of the gel also allows for favourable permeability of oxygen and nutrients to the bacteria colonised inside the beads. The bacteria in turn break down sludge-producing wastewater via self-oxidation, eliminating Nitrates, Phosphates, and Ammonia. This reduces sludge formation, minimizes the plant's footprint, and promotes sustainable treatment. However, it should be noted the bacteria colonised within the porous beads require an optimal environment for growth and stability to function effectively. Factors including pore size, porosity, pore interconnectivity and mechanical strength of the crosslinked network subjected to hydraulic impact loading require further investigation to optimise bacterial performance within the hydrogel. In this project we will conduct thorough material characterisation to understand the specific role of PVA hydrogel beads in facilitating bacteria growth within hydrogel while preventing the growth of Metazoa or Protozoa. Additionally, we will assess the limitations compared to alternative technologies, establishing a foundation for further hydrogel development research for wastewater treatment applications.

Project

Polyethylene terephthalate (PET) is one of the landfills' largest components of post-consumer plastics. Chemical PET decomposition and conversion into reusable chemical products of added value is one of the vital recycling strategies for this material. Glycolysis is the most widely studied reaction and it can be described as a molecular depolymerisation process by transesterification between PET ester groups and a diol, usually ethylene glycol (EG) in excess, to obtain the monomer bis(2-hydroxyethyl terephthalate) (BHET). The Glycolysis reaction is very slow and performed at a high temperature (180-260 ⁰C) in the presence of a toxic catalyst such as heavy metal salts. To overcome these disadvantages, a catalyst having an environment-friendly nature and high activity in polyester degradation is required. This research will investigate the use of green solvents as catalysts to promote an economical and environmentally friendly technique for the chemical recycling of coloured PET. The main goal of this proposed research is to design and use the different types of green solvents with high catalyst activity in glycolysis reaction to reduce the reaction time and temperature and increase the selectivity of reaction toward the BHET.

Project

Red wine is rich in antioxidants that protect human cells from oxidative damage, but excessive alcohol consumption can lead to chronic diseases. To mitigate these risks, we aim to reduce the alcohol content in wine using membrane technology. We are seeking a Chemical & Materials Engineering student to conduct a literature study on suitable membrane materials and yeast strains for low-alcohol wine production, as well as assist in membrane characterisations and wine sample analysis.

The preferred starting date is Nov 2023. However, not crucial.

Skills required: proficient writing and good experimental skills.

Project

In New Zealand, winery waste has been steadily increasing with the growing demand for New Zealand wine in the global market. Developing a reliable valorization bioprocess of winery waste will save disposal costs for the industry and avoid adverse ecological effects from improper treatments. This summer project focuses on performing a life cycle analysis (LCA) of a newly developed bioprocess that converts winery waste into valuable chemicals like caproate. This bioprocess operates under mild, anaerobic conditions in bioreactors, rendering it scalable with low capital and operation costs. Our research analyzes the environmental performance of this bioprocess under various operational conditions to identify technological bottlenecks affecting its social and environmental impact.

Skills required: Chemical and Materials Engineering Part III or IV UG students.

Project

Rechargeable batteries are very efficient and reliable electrical energy storage devices. Their plays a critical role in transmitting and distributing electrical energy, especially, with the introduction of electrical vehicles in last a few decades. Compared to lithium-ion and other commercial batteries, magnesium-based rechargeable batteries show low cost and high volumetric capacity advantages. However, the unstable solid-electrolyte interphase affects electrochemical charge and discharge performance.

Project Aims: This exploratory research projects aims to design and develop high performance magnesium-based rechargeable batteries, and understand their electrochemical behaviour.

Requirements: The student should be enthusiastic and interested in energy storage area.

Project

Low back pain impacts hugely on the quality of life, and the related socio-economic and medical costs are known to be very high. Arthritic degeneration of the cartilage layer within the lumbar facet joints is a known cause of low back pain. Specifically, this degeneration will involve microstructural breakdown of the cartilage and its integration with the underlying bone, and the inevitable loss of normal biomechanical function. However, there is still little published information concerning the morphology of the bone and cartilage layer in the sheep facet joints and the precise microstructure of the cartilage. This project will investigate unresolved mysteries relating to the morphology of the facet joints and the precise microstructure of the cartilage layer in sheep lumbar spines. The project will involve review of literature, practical laboratory work like microscopy, image and data analysis. The project should appeal to someone with an interest in biological materials.